Immunoglobulin A coating identifies colitogenic bacteria in inflammatory bowel disease.
Palm Noah W,de Zoete Marcel R,Cullen Thomas W,Barry Natasha A,Stefanowski Jonathan,Hao Liming,Degnan Patrick H,Hu Jianzhong,Peter Inga,Zhang Wei,Ruggiero Elizabeth,Cho Judy H,Goodman Andrew L,Flavell Richard A
Specific members of the intestinal microbiota dramatically affect inflammatory bowel disease (IBD) in mice. In humans, however, identifying bacteria that preferentially affect disease susceptibility and severity remains a major challenge. Here, we used flow-cytometry-based bacterial cell sorting and 16S sequencing to characterize taxa-specific coating of the intestinal microbiota with immunoglobulin A (IgA-SEQ) and show that high IgA coating uniquely identifies colitogenic intestinal bacteria in a mouse model of microbiota-driven colitis. We then used IgA-SEQ and extensive anaerobic culturing of fecal bacteria from IBD patients to create personalized disease-associated gut microbiota culture collections with predefined levels of IgA coating. Using these collections, we found that intestinal bacteria selected on the basis of high coating with IgA conferred dramatic susceptibility to colitis in germ-free mice. Thus, our studies suggest that IgA coating identifies inflammatory commensals that preferentially drive intestinal disease. Targeted elimination of such bacteria may reduce, reverse, or even prevent disease development.
Molecular antagonism and plasticity of regulatory and inflammatory T cell programs.
Yang Xuexian O,Nurieva Roza,Martinez Gustavo J,Kang Hong Soon,Chung Yeonseok,Pappu Bhanu P,Shah Bhavin,Chang Seon Hee,Schluns Kimberly S,Watowich Stephanie S,Feng Xin-Hua,Jetten Anton M,Dong Chen
Regulatory T (Treg) and T helper 17 (Th17) cells were recently proposed to be reciprocally regulated during differentiation. To understand the underlying mechanisms, we utilized a Th17 reporter mouse with a red fluorescent protein (RFP) sequence inserted into the interleukin-17F (IL-17F) gene. Using IL-17F-RFP together with a Foxp3 reporter, we found that the development of Th17 and Foxp3(+) Treg cells was associated in immune responses. Although TGF-beta receptor I signaling was required for both Foxp3 and IL-17 induction, SMAD4 was only involved in Foxp3 upregulation. Foxp3 inhibited Th17 differentiation by antagonizing the function of the transcription factors RORgammat and ROR*. In contrast, IL-6 overcame this suppressive effect of Foxp3 and, together with IL-1, induced genetic reprogramming in Foxp3(+) Treg cells. STAT3 regulated Foxp3 downregulation, whereas STAT3, RORgamma, and ROR* were required for IL-17 expression in Treg cells. Our data demonstrate molecular antagonism and plasticity of Treg and Th17 cell programs.
Generation of T follicular helper cells is mediated by interleukin-21 but independent of T helper 1, 2, or 17 cell lineages.
Nurieva Roza I,Chung Yeonseok,Hwang Daehee,Yang Xuexian O,Kang Hong Soon,Ma Li,Wang Yi-hong,Watowich Stephanie S,Jetten Anton M,Tian Qiang,Dong Chen
After activation, CD4(+) helper T (Th) cells differentiate into distinct effector subsets. Although chemokine (C-X-C motif) receptor 5-expressing T follicular helper (Tfh) cells are important in humoral immunity, their developmental regulation is unclear. Here we show that Tfh cells had a distinct gene expression profile and developed in vivo independently of the Th1 or Th2 cell lineages. Tfh cell generation was regulated by ICOS ligand (ICOSL) expressed on B cells and was dependent on interleukin-21 (IL-21), IL-6, and signal transducer and activator of transcription 3 (STAT3). However, unlike Th17 cells, differentiation of Tfh cells did not require transforming growth factor beta (TGF-beta) or Th17-specific orphan nuclear receptors RORalpha and RORgamma in vivo. Finally, naive T cells activated in vitro in the presence of IL-21 but not TGF-beta signaling preferentially acquired Tfh gene expression and promoted germinal-center reactions in vivo. This study thus demonstrates that Tfh is a distinct Th cell lineage.
The signaling protein Wnt4 enhances thymopoiesis and expands multipotent hematopoietic progenitors through beta-catenin-independent signaling.
Louis Isabelle,Heinonen Krista M,Chagraoui Jalila,Vainio Seppo,Sauvageau Guy,Perreault Claude
Despite studies based on deletion or activation of intracellular components of the canonical Wingless related (Wnt) pathway, the role of Wnts in hematolymphopoiesis remains controversial. Using gain-of-function and loss-of-function models, we found that Wnt4 differentially affected diverse subsets of hematopoietic stem and progenitor cells. Bone-marrow and thymic Lin(-)Sca1(+)Kit(hi) cells (LSKs) were the key targets of Wnt4. In adult mice, Wnt4-induced expansion of Flt3(+) bone-marrow LSKs (lymphoid-primed multipotent progenitors) led to a sizeable accumulation of the most immature thymocyte subsets (upstream of beta-selection) and a major increase in thymopoiesis. Conversely, Wnt4(-/-) neonates showed low frequencies of bone-marrow LSKs and thymic hypocellularity. We provide compelling evidence that Wnt4 activates noncanonical (beta-catenin-independent) signaling and that its effects on hematopoietic cells are mainly non-cell-autonomous. Our work shows that Wnt4 overexpression has a unique ability to expand Flt3(+) LSKs in adults and demonstrates that noncanonical Wnt signaling regulates thymopoiesis.
The chemokine receptor CCR5 plays a key role in the early memory CD8+ T cell response to respiratory virus infections.
Kohlmeier Jacob E,Miller Shannon C,Smith Joanna,Lu Bao,Gerard Craig,Cookenham Tres,Roberts Alan D,Woodland David L
Innate recognition of invading pathogens in peripheral tissues results in the recruitment of circulating memory CD8(+) T cells to sites of localized inflammation during the early phase of a recall response. However, the mechanisms that control the rapid recruitment of these cells to peripheral sites are poorly understood, particularly in relation to influenza and parainfluenza infections of the respiratory tract. In this study, we demonstrate a crucial role for C-C chemokine receptor 5 (CCR5) in the accelerated recruitment of memory CD8(+) T cells to the lung airways during virus challenge. Most importantly, CCR5 deficiency resulted in decreased recruitment of memory T cells expressing key effector molecules and impaired control of virus replication during the initial stages of a secondary response. These data highlight the critical importance of early memory T cell recruitment for the efficacy of cellular immunity in the lung.
Engagement of the type I interferon receptor on dendritic cells inhibits T helper 17 cell development: role of intracellular osteopontin.
Shinohara Mari L,Kim June-Ho,Garcia Virgilio A,Cantor Harvey
Mechanisms that prevent inappropriate or excessive interleukin-17-producing T helper (Th17) cell responses after microbial infection may be necessary to avoid autoimmunity. Here, we define a pathway initiated by engagement of type I IFN receptor (IFNAR) expressed by dendritic cells (DC) that culminated in suppression of Th17 cell differentiation. IFNAR-dependent inhibition of an intracellular translational isoform of Osteopontin, termed Opn-i, derepressed interleukin-27 (IL-27) secretion and prevented efficient Th17 responses. Moreover, Opn-i expression in DC and microglia regulated the type and intensity of experimental autoimmune encephalomyelitis (EAE). Mice containing DC deficient in Opn-i produced excessive amounts of IL-27 and developed a delayed disease characterized by an enhanced Th1 response compared with the dominant Th17 response of Opn-sufficient mice. Definition of the IFNAR-Opn-i axis that controls Th17 development provides insight into regulation of Th cell sublineage development and the molecular basis of type I interferon therapy for MS and other autoimmune diseases.
Thymic selection determines gammadelta T cell effector fate: antigen-naive cells make interleukin-17 and antigen-experienced cells make interferon gamma.
Jensen Kirk D C,Su Xiaoqin,Shin Sunny,Li Luke,Youssef Sawsan,Yamasaki Sho,Steinman Lawrence,Saito Takashi,Locksley Richard M,Davis Mark M,Baumgarth Nicole,Chien Yueh-hsiu
gammadelta T cells uniquely contribute to host immune defense, but how this is accomplished remains unclear. Here, we analyzed the nonclassical major histocompatibility complex class I T10 and T22-specific gammadelta T cells in mice and found that encountering antigen in the thymus was neither required nor inhibitory for their development. But when triggered through the T cell receptor, ligand-naive lymphoid-gammadelta T cells produced IL-17, whereas ligand-experienced cells made IFN-gamma. Immediately after immunization, a large fraction of IL-17(+) gammadelta T cells were found in the draining lymph nodes days before the appearance of antigen-specific IL-17(+) *beta T cells. Thus, thymic selection determines the effector fate of gammadelta T cells rather than constrains their antigen specificities. The swift IL-17 response mounted by antigen-naive gammadelta T cells suggests a critical role for these cells at the onset of an acute inflammatory response to novel antigens.
A fundamental role for interleukin-21 in the generation of T follicular helper cells.
Vogelzang Alexis,McGuire Helen M,Yu Di,Sprent Jonathan,Mackay Charles R,King Cecile
T cell help to B cells is a fundamental property of adaptive immunity, yet only recently have many of the cellular and molecular mechanisms of T cell help emerged. T follicular helper (Tfh) cells are the CD4(+) T helper cells that provide cognate help to B cells for high-affinity antibody production in germinal centers (GC). Tfh cells produce interleukin-21 (IL-21), and we show that IL-21 was necessary for GC formation. However, the central role of IL-21 in GC formation reflected its effects on Tfh cell generation rather than on B cells. Expression of the inducible costimulator (ICOS) was necessary for optimal production of IL-21, indicative of interplay between these two Tfh cell-expressed molecules. Finally, we demonstrate that IL-21's costimulatory capacity for T helper cell differentiation operated at the level of the T cell receptor signalosome through Vav1, a signaling molecule that controls T cell helper function. This study reveals a previously unappreciated role for Tfh cells in the formation of the GC and isotype switching through a CD4(+) T cell-intrinsic requirement for IL-21.
Adaptive Foxp3+ regulatory T cell-dependent and -independent control of allergic inflammation.
Curotto de Lafaille Maria A,Kutchukhidze Nino,Shen Shiqian,Ding Yi,Yee Herman,Lafaille Juan J
Adaptive Foxp3(+) regulatory T (Treg) cells develop during induction of mucosal tolerance and after immunization. Large numbers of Foxp3(+) T cells have been found in inflamed tissues. We investigated the role of adaptive Foxp3(+) Treg cells in mucosal tolerance and in chronic allergic lung inflammation. We used two strains of mice that are devoid of naturally occurring Treg cells; one is capable of generating adaptive Foxp3(+) Treg cells upon exposure to antigen, whereas the other is deficient in both naturally occurring and adaptive Foxp3(+) Treg cells. We found that adaptive Foxp3(+) Treg cells were essential for establishing mucosal tolerance and for suppressing IL-4 production and lymphoid neogenesis in chronic inflammation, whereas IL-5 production and eosinophilia could be controlled by Foxp3-independent, IFN-gamma-dependent mechanisms. Thus, whereas adaptive Foxp3(+) Treg cells regulate sensitization to allergens and the severity of chronic inflammation, IFN-gamma-producing cells can play a beneficial role in inflammatory conditions involving eosinophils.
A lysosomal protein negatively regulates surface T cell antigen receptor expression by promoting CD3zeta-chain degradation.
Ouchida Rika,Yamasaki Sho,Hikida Masaki,Masuda Keiji,Kawamura Kiyoko,Wada Akihiko,Mochizuki Shigenobu,Tagawa Masatoshi,Sakamoto Akemi,Hatano Masahiko,Tokuhisa Takeshi,Koseki Haruhiko,Saito Takashi,Kurosaki Tomohiro,Wang Ji-Yang
Modulation of surface T cell antigen receptor (TCR) expression is an important mechanism for the regulation of immune responses and the prevention of T cell hyperactivation and autoimmunity. The TCR is rapidly internalized after antigen stimulation and then degraded in lysosomes. However, few of the molecules involved in this process have been identified. We demonstrate that the lysosomal protein LAPTM5 negatively regulated surface TCR expression by specifically interacting with the invariant signal-transducing CD3zeta chain and promoting its degradation without affecting other CD3 proteins, CD3epsilon, CD3delta, or CD3gamma. TCR downmodulation required the polyproline-tyrosine motifs and the ubiquitin-interacting motif of LAPTM5. LAPTM5 deficiency resulted in elevated TCR expression on both CD4(+)CD8(+) thymocytes and spleen T cells after CD3 stimulation, as well as enhanced T cell responses in vitro and in vivo. These results identify a lysosomal protein important for CD3zeta degradation and illustrate a unique mechanism for the control of surface TCR expression and T cell activation.
Enhanced recruitment of CX3CR1+ T cells by mucosal endothelial cell-derived fractalkine in inflammatory bowel disease.
Sans Miquel,Danese Silvio,de la Motte Carol,de Souza Heitor S P,Rivera-Reyes Brenda M,West Gail A,Phillips Manijeh,Katz Jeffry A,Fiocchi Claudio
BACKGROUND & AIMS:Fractalkine (FKN/CX3CL1) is a unique chemokine combining adhesive and chemotactic properties. We investigated FKN production by the mucosal microvasculature in inflammatory bowel disease (IBD), its capacity for leukocyte recruitment into the gut, and the number of CX3CR1+ cells in the circulation and mucosa of IBD patients. METHODS:The expression of FKN by human intestinal microvascular endothelial cells (HIMECs) and CX3CR1 by circulating cells was evaluated by flow cytometry, and mucosal CX3CR1+ cells were enumerated by immunohistochemistry. The capacity of FKN to mediate leukocyte binding to HIMECs was assessed by immunoblockade, and to induce HIMEC transmigration by a Transwell system. RESULTS:The spontaneously low HIMEC FKN expression was enhanced markedly by tumor necrosis factor-alpha plus interferon-gamma stimulation, or direct leukocyte contact. This effect was significantly stronger in IBD than control HIMECs. Up-regulation of HIMEC FKN expression was dependent on p38 and extracellular signal-regulated kinase phosphorylation, as was abrogated by selective mitogen-activated protein kinase inhibitors. Circulating T cells contained significantly higher numbers of CX3CR1+ cells in active IBD than inactive IBD or healthy subjects, and IBD mucosa contained significantly more CX3CR1+ cells than control mucosa. Antibody-blocking experiments showed that FKN was a major contributor to T- and monocytic-cell adhesion to HIMECs. Finally, FKN enhanced the expression of active beta1 integrin on leukocytes and mediated leukocyte HIMEC transmigration. CONCLUSIONS:In view of the capacity of FKN to mediate leukocyte adhesion, chemoattraction, and transmigration, its increased production by mucosal microvascular cells and increased numbers of circulating and mucosal CX3CR1+ cells in IBD point to a significant role of FKN in disease pathogenesis.
An extra dose of rituximab improves clinical response in rheumatoid arthritis patients with initial incomplete B cell depletion: a randomised controlled trial.
Vital Edward M,Dass Shouvik,Buch Maya H,Rawstron Andrew C,Emery Paul
Annals of the rheumatic diseases
OBJECTIVES:Since clinical non-response to 2×1000 mg rituximab has previously been found to be associated with incomplete B cell depletion, we determined, in a randomised controlled proof of concept study, whether patients with initial incomplete B cell depletion would benefit from an additional infusion of rituximab at week 4. METHODS:Patients with active rheumatoid arthritis despite methotrexate received a first infusion of rituximab 1000 mg and were tested for persistent B cells using highly sensitive flow cytometry on day 15. All received a second infusion of 1 g (according to license), but patients with persistent B cells were subsequently randomised double-blind to receive, 2 weeks later, either a third infusion of 1000 mg rituximab or placebo. Clinical response was determined by European League Against Rheumatism (EULAR) and American College of Rheumatology (ACR) criteria. RESULTS:Baseline characteristics were balanced between groups. Treatment with 3×1000 mg rituximab resulted in significantly greater depletion (lower B cell and plasmablast numbers between 8 and 28 weeks) paralleled by significantly better EULAR and ACR20 response rates at 40 weeks (p=0.035 and p=0.027, respectively) and 52 weeks (p=0.021 and p=0.043, respectively) compared with 2×1000 mg. Immunoglobulin titres remained stable in both arms, and adverse event rates were balanced. CONCLUSIONS:In rituximab-treated patients with incomplete B cell depletion (predictive of poor response), an extra 1000 mg infusion of rituximab at 4 weeks produced both better depletion and clinical responses than placebo with no worsening of safety. Degree of depletion is an important, but modifiable, determinant of response.
Eosinophil-mediated signalling attenuates inflammatory responses in experimental colitis.
Masterson Joanne C,McNamee Eóin N,Fillon Sophie A,Hosford Lindsay,Harris Rachel,Fernando Shahan D,Jedlicka Paul,Iwamoto Ryo,Jacobsen Elizabeth,Protheroe Cheryl,Eltzschig Holger K,Colgan Sean P,Arita Makoto,Lee James J,Furuta Glenn T
OBJECTIVE:Eosinophils reside in the colonic mucosa and increase significantly during disease. Although a number of studies have suggested that eosinophils contribute to the pathogenesis of GI inflammation, the expanding scope of eosinophil-mediated activities indicate that they also regulate local immune responses and modulate tissue inflammation. We sought to define the impact of eosinophils that respond to acute phases of colitis in mice. DESIGN:Acute colitis was induced in mice by administration of dextran sulfate sodium, 2,4,6-trinitrobenzenesulfonic acid or oxazolone to C57BL/6J (control) or eosinophil deficient (PHIL) mice. Eosinophils were also depleted from mice using antibodies against interleukin (IL)-5 or by grafting bone marrow from PHIL mice into control mice. Colon tissues were collected and analysed by immunohistochemistry, flow cytometry and reverse transcription PCR; lipids were analysed by mass spectroscopy. RESULTS:Eosinophil-deficient mice developed significantly more severe colitis, and their colon tissues contained a greater number of neutrophils, than controls. This compensatory increase in neutrophils was accompanied by increased levels of the chemokines CXCL1 and CXCL2, which attract neutrophils. Lipidomic analyses of colonic tissue from eosinophil-deficient mice identified a deficiency in the docosahexaenoic acid-derived anti-inflammatory mediator 10, 17- dihydroxydocosahexaenoic acid (diHDoHE), namely protectin D1 (PD1). Administration of an exogenous PD1-isomer (10S, 17S-DiHDoHE) reduced the severity of colitis in eosinophil-deficient mice. The PD1-isomer also attenuated neutrophil infiltration and reduced levels of tumour necrosis factor-α, IL-1β, IL-6 and inducible NO-synthase in colons of mice. Finally, in vitro assays identified a direct inhibitory effect of PD1-isomer on neutrophil transepithelial migration. CONCLUSIONS:Eosinophils exert a protective effect in acute mouse colitis, via production of anti-inflammatory lipid mediators.
Ischemic Cerebroprotection Conferred by Myeloid Lineage-Restricted or Global CD39 Transgene Expression.
Baek Amy E,Sutton Nadia R,Petrovic-Djergovic Danica,Liao Hui,Ray Jessica J,Park Joan,Kanthi Yogendra,Pinsky David J
BACKGROUND:Cerebral tissue damage after an ischemic event can be exacerbated by inflammation and thrombosis. Elevated extracellular ATP and ADP levels are associated with cellular injury, inflammation, and thrombosis. Ectonucleoside triphosphate diphosphohydrolase-1 (CD39), an enzyme expressed on the plasmalemma of leukocytes and endothelial cells, suppresses platelet activation and leukocyte infiltration by phosphohydrolyzing ATP/ADP. To investigate the effects of increased CD39 in an in vivo cerebral ischemia model, we developed a transgenic mouse expressing human CD39 (hCD39). METHODS:A floxed-stop sequence was inserted between the promoter and the hCD39 transcriptional start site, generating a mouse in which the expression of hCD39 can be controlled tissue-specifically using Cre recombinase mice. We generated mice that express hCD39 globally or in myeloid-lineage cells only. Cerebral ischemia was induced by middle cerebral artery occlusion. Infarct volumes were quantified by MRI after 48 hours. RESULTS:Both global and transgenic hCD39- and myeloid lineage CD39-overexpressing mice (transgenic, n=9; myeloid lineage, n=6) demonstrated significantly smaller cerebral infarct volumes compared with wild-type mice. Leukocytes from ischemic and contralateral hemispheres were analyzed by flow cytometry. Although contralateral hemispheres had equal numbers of macrophages and neutrophils, ischemic hemispheres from transgenic mice had less infiltration (n=4). Transgenic mice showed less neurological deficit compared with wild-type mice (n=6). CONCLUSIONS:This is the first report of transgenic overexpression of CD39 in mice imparting a protective phenotype after stroke, with reduced leukocyte infiltration, smaller infarct volumes, and decreased neurological deficit. CD39 overexpression, either globally or in myeloid lineage cells, quenches postischemic leukosequestration and reduces stroke-induced neurological injury.
Beta1 integrin deletion from the basal compartment of the mammary epithelium affects stem cells.
Taddei Ilaria,Deugnier Marie-Ange,Faraldo Marisa M,Petit Valérie,Bouvard Daniel,Medina Daniel,Fässler Reinhard,Thiery Jean Paul,Glukhova Marina A
Nature cell biology
The mammary gland epithelium comprises two major cell types: basal and luminal. Basal cells interact directly with the extracellular matrix (ECM) and express higher levels of the ECM receptors, integrins, than luminal cells. We show that deletion of beta1 integrin from basal cells abolishes the regenerative potential of the mammary epithelium and affects mammary gland development. The mutant epithelium was characterized by an abnormal ductal branching pattern and aberrant morphogenesis in pregnancy, although at the end of gestation, the secretory alveoli developed from beta1 integrin-positive progenitors. Lack of beta1 integrin altered the orientation of the basal-cell division axis and in mutant epithelium, in contrast to control tissue, the progeny of beta1 integrin-null basal cells, identified by a genetic marker, was found in the luminal compartment. These results reveal, for the first time, the essential role of the basal mammary epithelial cell-ECM interactions mediated by beta1 integrins in the maintenance of a functional stem cell population, mammary morphogenesis and segregation of the two major mammary cell lineages.
Measuring elastase, proteinase 3 and cathepsin G activities at the surface of human neutrophils with fluorescence resonance energy transfer substrates.
Korkmaz Brice,Attucci Sylvie,Juliano Maria Aparecida,Kalupov Timofey,Jourdan Marie-Lise,Juliano Luiz,Gauthier Francis
The neutrophil serine proteases (NSPs) elastase, proteinase 3 and cathepsin G are multifunctional proteases involved in pathogen destruction and the modulation of inflammatory processes. A fraction of secreted NSPs remains bound to the external plasma membrane, where they remain enzymatically active. This protocol describes the spectrofluorometric measurement of NSP activities on neutrophil surfaces using highly sensitive Abz-peptidyl-EDDnp fluorescence resonance energy transfer (FRET) substrates that fully discriminate between the three human NSPs. We describe FRET substrate synthesis, neutrophil purification and handling, and kinetic experiments on quiescent and activated cells. These are used to measure subnanomolar concentrations of membrane-bound or free NSPs in low-binding microplates and to quantify the activities of individual proteases in biological fluids like expectorations and bronchoalveolar lavages. The whole procedure, including neutrophil purification and kinetic measurements, can be done in 4-5 h and should not be longer because of the lifetime of neutrophils. Using this protocol will help identify the contributions of individual NSPs to the development of inflammatory diseases and may reveal these proteases to be targets for therapeutic inhibitors.
Substrate-induced gene expression (SIGEX) screening of metagenome libraries.
Uchiyama Taku,Watanabe Kazuya
Substrate-induced gene-expression screening (SIGEX) has been developed for isolating novel catabolic genes from environmental metagenomes, particularly genes that are difficult to obtain using conventional gene-cloning methods. In SIGEX, restriction enzyme-digested metagenome fragments are ligated into an operon-trap vector (e.g., p18GFP), and a library is constructed in a liquid culture by transforming a cloning host (e.g., Escherichia coli). The library is subjected to a substrate-dependent gene-induction assay, and positive cells are selected by detecting activity of a co-expressed marker (e.g., GFP) encoded in the vector. High-throughput screening is possible if fluorescence-activated cell sorting (FACS) is used to select GFP-expressing cells. The abovementioned SIGEX procedure requires approximately 17 d. In this protocol, a widely applicable SIGEX scheme is presented along with typical experimental results.
Purification and culture of nerve growth factor receptor (p75)-expressing basal forebrain cholinergic neurons.
Schnitzler Aletta C,Lopez-Coviella Ignacio,Blusztajn Jan Krzysztof
The activity of the basal forebrain cholinergic neurons (BFCNs) that innervate the cerebral cortex and hippocampus is essential for normal learning and memory. Here, we present a method to isolate and culture BFCNs from the embryonic murine septum that takes advantage of their restricted expression of the nerve growth factor receptor (p75) in conjunction with fluorescence-activated cell sorting. The septal region dissection, cell dissociation and staining process, and cell sorting parameters are described in detail. Sufficient cell yield and optimized cell culture conditions make this protocol suitable for multiple assays including immunocytochemistry, reverse transcriptase PCR, microarray profiling, acetylcholine measurements and electrophysiological assessment. The study of these neurons as a purified population will greatly advance our understanding of factors that influence their development and maintenance.
Culture of embryonic-like stem cells from human umbilical cord blood and onward differentiation to neural cells in vitro.
McGuckin Colin,Jurga Marcin,Ali Hamad,Strbad Marko,Forraz Nicolas
This 3-week protocol produces embryonic-like stem cells from human umbilical cord blood (CBEs) for neural differentiation using a three-step system (cell isolation/expansion/differentiation). The CBE isolation produces a highly purified fraction (CD45-, CD33-, CD7-, CD235a-) of small pluripotent stem cells (2-3 microm in diameter) coexpressing embryonic stem cell markers including Oct4 and Sox2. Initial CBE expansion is performed in high density (5-10 millions per ml) in the presence of extracellular matrix proteins and epidermal growth factor. Subsequent neural differentiation of CBEs requires sequential introduction of morphogenes, retinoic acid, brain-derived neurotrophic factor and cyclic AMP. Described methods emphasize defined media and reagents at all stages of the experiment comparable to protocols described for culturing human embryonic stem cells and cells from other somatic stem cell sources. Neural progenitor and cells generated from CBEs may be used for in vitro drug testing and cell-based assays and potentially for clinical transplantation.
Isolation of endothelial cells from fresh tissues.
van Beijnum Judy R,Rousch Mat,Castermans Karolien,van der Linden Edith,Griffioen Arjan W
Here, we present a protocol for the isolation of endothelial cells (ECs) from tissues. ECs make up a minor population of cells in a tissue, but play a major role in tissue homeostasis, as well as in diverse pathologies. To understand the biology of ECs, characterization of this cell population is highly desirable, but requires the availability of purified cells. For this purpose, tissues are mechanically minced and subsequently digested enzymatically with collagenase and dispase. ECs in the resulting single-cell suspension are labeled with Abs against EC surface antigens and separated from the remainder of the cells and debris by capture with magnetic beads or by high-speed cell sorting. Purified ECs are viable and suitable for characterization of diverse cellular properties. This protocol is optimized for human tissues but can also be adapted for use with other species. Depending on the tissue, the procedure can be completed in approximately 6 h.
Flow cytometry in tumours of the brain.
Frederiksen P,Reske-Nielsen E,Bichel P
Flow cytometry was used for studying the distribution of single cell DNA content in biopsy material from 85 patients with benign and malignant lesions of the brain and spinal cord. In inflammatory lesions and in most benign tumours, cells with diploid DNA values were observed, sometimes with additional smaller amounts of tetraploid DNA. Cells from malignant tumours were characterized by marked hyperploid DNA values. Flow cytometry is found a rapid and valuable method adding important information to the biological nature of tumours of the central nervous system.
A microengraving method for rapid selection of single cells producing antigen-specific antibodies.
Love J Christopher,Ronan Jehnna L,Grotenbreg Gijsbert M,van der Veen Annemarthe G,Ploegh Hidde L
Monoclonal antibodies that recognize specific antigens of interest are used as therapeutic agents and as tools for biomedical research. Discovering a single monoclonal antibody requires retrieval of an individual hybridoma from polyclonal mixtures of cells producing antibodies with a variety of specificities. The time required to isolate hybridomas by a limiting serial-dilution, however, has restricted the diversity and breadth of available antibodies. Here we present a soft lithographic method based on intaglio printing to generate microarrays comprising the secreted products of single cells. These engraved arrays enable a rapid (<12 h) and high-throughput (>100,000 individual cells) system for identification, recovery and clonal expansion of cells producing antigen-specific antibodies. This method can be adapted, in principle, to detect any secreted product in a multiplexed manner.
Loss of Junctional Adhesion Molecule A Promotes Severe Steatohepatitis in Mice on a Diet High in Saturated Fat, Fructose, and Cholesterol.
Rahman Khalidur,Desai Chirayu,Iyer Smita S,Thorn Natalie E,Kumar Pradeep,Liu Yunshan,Smith Tekla,Neish Andrew S,Li Hongliang,Tan Shiyun,Wu Pengbo,Liu Xiaoxiong,Yu Yuanjie,Farris Alton B,Nusrat Asma,Parkos Charles A,Anania Frank A
BACKGROUND & AIMS:There is evidence from clinical studies that compromised intestinal epithelial permeability contributes to the development of nonalcoholic steatohepatitis (NASH), but the exact mechanisms are not clear. Mice with disruption of the gene (F11r) encoding junctional adhesion molecule A (JAM-A) have defects in intestinal epithelial permeability. We used these mice to study how disruption of the intestinal epithelial barrier contributes to NASH. METHODS:Male C57BL/6 (control) or F11r(-/-) mice were fed a normal diet or a diet high in saturated fat, fructose, and cholesterol (HFCD) for 8 weeks. Liver and intestinal tissues were collected and analyzed by histology, quantitative reverse-transcription polymerase chain reaction, and flow cytometry. Intestinal epithelial permeability was assessed in mice by measuring permeability to fluorescently labeled dextran. The intestinal microbiota were analyzed using 16S ribosomal RNA sequencing. We also analyzed biopsy specimens from proximal colons of 30 patients with nonalcoholic fatty liver disease (NAFLD) and 19 subjects without NAFLD (controls) undergoing surveillance colonoscopy. RESULTS:F11r(-/-) mice fed a HFCD, but not a normal diet, developed histologic and pathologic features of severe NASH including steatosis, lobular inflammation, hepatocellular ballooning, and fibrosis, whereas control mice fed a HFCD developed only modest steatosis. Interestingly, there were no differences in body weight, ratio of liver weight:body weight, or glucose homeostasis between control and F11r(-/-) mice fed a HFCD. In these mice, liver injury was associated with significant increases in mucosal inflammation, tight junction disruption, and intestinal epithelial permeability to bacterial endotoxins, compared with control mice or F11r(-/-) mice fed a normal diet. The HFCD led to a significant increase in inflammatory microbial taxa in F11r(-/-) mice, compared with control mice. Administration of oral antibiotics or sequestration of bacterial endotoxins with sevelamer hydrochloride reduced mucosal inflammation and restored normal liver histology in F11r(-/-) mice fed a HFCD. Protein and transcript levels of JAM-A were significantly lower in the intestinal mucosa of patients with NAFLD than without NAFLD; decreased expression of JAM-A correlated with increased mucosal inflammation. CONCLUSIONS:Mice with defects in intestinal epithelial permeability develop more severe steatohepatitis after a HFCD than control mice, and colon tissues from patients with NAFLD have lower levels of JAM-A and higher levels of inflammation than subjects without NAFLD. These findings indicate that intestinal epithelial barrier function and microbial dysbiosis contribute to the development of NASH. Restoration of intestinal barrier integrity and manipulation of gut microbiota might be developed as therapeutic strategies for patients with NASH.
Expression of platelet collagen receptor glycoprotein VI is associated with acute coronary syndrome.
Bigalke Boris,Lindemann Stephan,Ehlers Raila,Seizer Peter,Daub Karin,Langer Harald,Schonberger Tanja,Kremmer Elisabeth,Siegel-Axel Dorothea,May Andreas E,Gawaz Meinrad
European heart journal
AIMS:Platelet collagen receptor glycoprotein VI (GPVI) is critical for the formation of arterial thrombosis. In this observational study, we examined the platelet surface expression of GPVI in patients with symptomatic coronary artery disease (CAD). METHODS AND RESULTS:We evaluated a consecutive cohort of 367 patients with symptomatic CAD, who underwent coronary angiography. The surface expression of platelet activation markers (GPVI, CD62P, and CD42b) was determined by flow cytometry. Patients with acute coronary syndrome (ACS) showed a significantly enhanced GPVI expression on admission when compared with patients with stable angina pectoris (SAP) (ACS: 21.4+/-9.7; SAP: 18.6+/-7.1 mean fluorescence intensity+/-SD; P=0.004). The expression of GPVI correlated with CD62P (r=0.702; P=0.001). Logistic regression analysis demonstrated that on admission, elevated platelet GPVI expression was associated with ACS, independent of markers of myocardial necrosis such as troponin and creatine kinase. CONCLUSION:Platelet GPVI surface expression is elevated in patients with ACS and is associated with imminent acute coronary events. The determination of the platelet-specific thrombotic marker GPVI may help to identify patients at risk before myocardial ischaemia is evident.
Comparison of Immature Platelet Count to Established Predictors of Platelet Reactivity During Thienopyridine Therapy.
Stratz Christian,Bömicke Timo,Younas Iris,Kittel Anja,Amann Michael,Valina Christian M,Nührenberg Thomas,Trenk Dietmar,Neumann Franz-Josef,Hochholzer Willibald
Journal of the American College of Cardiology
BACKGROUND:Previous data suggest that reticulated platelets significantly affect antiplatelet response to thienopyridines. It is unknown whether parameters describing reticulated platelets can predict antiplatelet response to thienopyridines. OBJECTIVES:The authors sought to determine the extent to which parameters describing reticulated platelets can predict antiplatelet response to thienopyridine loading compared with established predictors. METHODS:This study randomized 300 patients undergoing elective coronary stenting to loading with clopidogrel 600 mg, prasugrel 30 mg, or prasugrel 60 mg. Adenosine diphosphate (ADP)-induced platelet reactivity was assessed by impedance aggregometry before loading (intrinsic platelet reactivity) and again on day 1 after loading. Multiple parameters of reticulated platelets were assessed by automated whole blood flow cytometry: absolute immature platelet count (IPC), immature platelet fraction, and highly fluorescent immature platelet fraction. RESULTS:Each parameter of reticulated platelets correlated significantly with ADP-induced platelet reactivity (p < 0.01 for all 3 parameters). In a multivariable model including all 3 parameters, only IPC remained a significant predictor of platelet reactivity (p < 0.001). In models adjusting each of the 3 parameters for known predictors of on-treatment platelet reactivity including cytochrome P450 2C19 (CYP2C19) polymorphisms, age, body mass index, diabetes, and intrinsic platelet reactivity, only IPC prevailed as an independent predictor (p = 0.001). In this model, IPC was the strongest predictor of on-treatment platelet reactivity followed by intrinsic platelet reactivity. CONCLUSIONS:IPC is the strongest independent platelet count-derived predictor of antiplatelet response to thienopyridine treatment. Given its easy availability, together with its even stronger association with on-treatment platelet reactivity compared with known predictors, including the CYP2C19*2 polymorphism, IPC may become the preferred predictor of antiplatelet response to thienopyridine treatment. (Impact of Extent of Clopidogrel-Induced Platelet Inhibition During Elective Stent Implantation on Clinical Event Rate-Advanced Loading Strategies [ExcelsiorLOAD]; DRKS00006102).
A key role for Fut1-regulated angiogenesis and ICAM-1 expression in K/BxN arthritis.
Amin Mohammad A,Campbell Phillip L,Ruth Jeffrey H,Isozaki Takeo,Rabquer Bradley J,Alex Stinson W,O'Brien Martin,Edhayan Gautam,Ohara Ray A,Vargo Jonathon,Domino Steven E,Koch Alisa E
Annals of the rheumatic diseases
OBJECTIVES:Angiogenesis contributes to the pathogenesis of rheumatoid arthritis. Fucosyltransferases (Futs) are involved in angiogenesis and tumour growth. Here, we examined the role of Fut1 in angiogenesis and K/BxN serum transfer arthritis. METHODS:We examined Fut1 expression in human dermal microvascular endothelial cells (HMVECs) by quantitative PCR. We performed a number of angiogenesis assays to determine the role of Fut1 using HMVECs, Fut1 null (Fut1(-/-)), and wild type (wt) endothelial cells (ECs) and mice. K/BxN serum transfer arthritis was performed to determine the contribution of Fut1-mediated angiogenesis in Fut1(-/-) and wt mice. A static adhesion assay was implemented with RAW264.7 (mouse macrophage cell line) and mouse ECs. Quantitative PCR, immunofluorescence and flow cytometry were performed with Fut1(-/-) and wt ECs for adhesion molecule expression. RESULTS:Tumour necrosis factor-α induced Fut1 mRNA and protein expression in HMVECs. HMVECs transfected with Fut1 antisense oligodeoxynucleotide and Fut1(-/-) ECs formed significantly fewer tubes on Matrigel. Fut1(-/-) mice had reduced angiogenesis in Matrigel plug and sponge granuloma angiogenesis assays compared with wt mice. Fut1(-/-) mice were resistant to K/BxN serum transfer arthritis and had decreased angiogenesis and leucocyte ingress into inflamed joints. Adhesion of RAW264.7 cells to wt mouse ECs was significantly reduced when Fut1 was lacking. Fut1(-/-) ECs had decreased intercellular adhesion molecule-1 (ICAM-1) expression at mRNA and protein levels compared with wt ECs. ICAM-1 was also decreased in Fut1(-/-) arthritic ankle cryosections compared with wt ankles. CONCLUSIONS:Fut1 plays an important role in regulating angiogenesis and ICAM-1 expression in inflammatory arthritis.
Granulocyte colony-stimulating factor (G-CSF) treatment of childhood acute myeloid leukemias that overexpress the differentiation-defective G-CSF receptor isoform IV is associated with a higher incidence of relapse.
Ehlers Stephanie,Herbst Christin,Zimmermann Martin,Scharn Nicole,Germeshausen Manuela,von Neuhoff Nils,Zwaan Christian Michel,Reinhardt Katarina,Hollink Iris H,Klusmann Jan-Henning,Lehrnbecher Thomas,Roettgers Silja,Stary Jan,Dworzak Michael,Welte Karl,Creutzig Ursula,Reinhardt Dirk
Journal of clinical oncology : official journal of the American Society of Clinical Oncology
PURPOSE:This prospective, multicenter Acute Myeloid Leukemia Berlin-Frankfurt-Muenster (AML-BFM) 98 study randomly tested the ability of granulocyte colony-stimulating factor (G-CSF) to reduce infectious complications and to improve outcomes in children and adolescents with acute myeloid leukemia (AML). However, a trend toward an increased incidence of relapses in the standard-risk (SR) group after G-CSF treatment was observed. PATIENTS AND METHODS:Of 154 SR patients in the AML-BFM 98 cohort, 50 patients were tested for G-CSF receptor (G-CSFR) RNA isoform I and IV expression, G-CSFR cell surface expression, and acquired mutations in the G-CSFR gene. RESULTS:In patients randomly assigned to receive G-CSF after induction, 16 patients overexpressing the G-CSFR isoform IV showed an increased 5-year cumulative incidence of relapse (50% +/- 13%) compared with 14 patients with low-level isoform IV expression (14% +/- 10%; log-rank P = .04). The level of G-CSFR isoform IV had no significant effect in patients not receiving G-CSF (P = .19). Multivariate analyses of the G-CSF-treated subgroup, including the parameters G-CSFR isoform IV overexpression, sex, and favorable cytogenetics as covariables, revealed the prognostic relevance of G-CSFR isoform IV overexpression for 5-year event-free survival (P = .031) and the 5-year cumulative incidence of relapse (P = .049). CONCLUSION:Our results demonstrate that children and adolescents with AMLs that overexpress the differentiation-defective G-CSFR isoform IV respond to G-CSF administration after induction, but with a significantly higher incidence of relapse.
Follistatin-like protein 1 regulates chondrocyte proliferation and chondrogenic differentiation of mesenchymal stem cells.
Chaly Yury,Blair Harry C,Smith Sonja M,Bushnell Daniel S,Marinov Anthony D,Campfield Brian T,Hirsch Raphael
Annals of the rheumatic diseases
OBJECTIVES:Chondrocytes, the only cells in the articular cartilage, play a pivotal role in osteoarthritis (OA) because they are responsible for maintenance of the extracellular matrix (ECM). Follistatin-like protein 1 (FSTL1) is a secreted protein found in mesenchymal stem cells (MSCs) and cartilage but whose function is unclear. FSTL1 has been shown to modify cell growth and survival. In this work, we sought to determine whether FSTL1 could regulate chondrogenesis and chondrogenic differentiation of MSCs. METHODS:To study the role of FSTL1 in chondrogenesis, we used FSTL1 knockout (KO) mice generated in our laboratory. Proliferative capacity of MSCs, obtained from skulls of E18.5 embryos, was analysed by flow cytometry. Chondrogenic differentiation of MSCs was carried out in a pellet culture system. Gene expression differences were assessed by microarray analysis and real-time PCR. Phosphorylation of Smad3, p38 MAPK and Akt was analysed by western blotting. RESULTS:The homozygous FSTL1 KO embryos showed extensive skeletal defects and decreased cellularity in the vertebral cartilage. Cell proliferation of FSTL1-deficient MSCs was reduced. Gene expression analysis in FSTL1 KO MSCs revealed dysregulation of multiple genes important for chondrogenesis. Production of ECM proteoglycans and collagen II expression were decreased in FSTL1-deficient MSCs differentiated into chondrocytes. Transforming growth factor β signalling in FSTL1 KO cells was significantly suppressed. CONCLUSIONS:FSTL1 is a potent regulator of chondrocyte proliferation, differentiation and expression of ECM molecules. Our findings may lead to the development of novel strategies for cartilage repair and provide new disease-modifying treatments for OA.
The proteasome inhibitior bortezomib depletes plasma cells and ameliorates clinical manifestations of refractory systemic lupus erythematosus.
Alexander Tobias,Sarfert Ramona,Klotsche Jens,Kühl Anja A,Rubbert-Roth Andrea,Lorenz Hannes-Martin,Rech Jürgen,Hoyer Bimba F,Cheng Qingyu,Waka Aderajew,Taddeo Adriano,Wiesener Michael,Schett Georg,Burmester Gerd-Rüdiger,Radbruch Andreas,Hiepe Falk,Voll Reinhard E
Annals of the rheumatic diseases
OBJECTIVES:To investigate whether bortezomib, a proteasome inhibitor approved for treatment of multiple myeloma, induces clinically relevant plasma cell (PC) depletion in patients with active, refractory systemic lupus erythematosus (SLE). METHODS:Twelve patients received a median of two (range 1-4) 21-day cycles of intravenous bortezomib (1.3 mg/m(2)) with the coadministration of dexamethasone (20 mg) for active SLE. Disease activity was assessed using the SLEDAI-2K score. Serum concentrations of anti-double-stranded DNA (anti-dsDNA) and vaccine-induced protective antibodies were monitored. Flow cytometry was performed to analyse peripheral blood B-cells, PCs and Siglec-1 expression on monocytes as surrogate marker for type-I interferon (IFN) activity. RESULTS:Upon proteasome inhibition, disease activity significantly declined and remained stable for 6 months on maintenance therapies. Nineteen treatment-emergent adverse events occurred and, although mostly mild to moderate, resulted in treatment discontinuation in seven patients. Serum antibody levels significantly declined, with greater reductions in anti-dsDNA (∼60%) than vaccine-induced protective antibody titres (∼30%). Bortezomib significantly reduced the numbers of peripheral blood and bone marrow PCs (∼50%), but their numbers increased between cycles. Siglec-1 expression on monocytes significantly declined. CONCLUSIONS:These findings identify proteasome inhibitors as a putative therapeutic option for patients with refractory SLE by targeting PCs and type-I IFN activity, but our results must be confirmed in controlled trials.
A pro-inflammatory role for Th22 cells in Helicobacter pylori-associated gastritis.
Zhuang Yuan,Cheng Ping,Liu Xiao-fei,Peng Liu-sheng,Li Bo-sheng,Wang Ting-ting,Chen Na,Li Wen-hua,Shi Yun,Chen Weisan,Pang Ken C,Zeng Ming,Mao Xu-hu,Yang Shi-ming,Guo Hong,Guo Gang,Liu Tao,Zuo Qian-fei,Yang Hui-jie,Yang Liu-yang,Mao Fang-yuan,Lv Yi-pin,Zou Quan-ming
OBJECTIVE:Helper T (Th) cell responses are critical for the pathogenesis of Helicobacter pylori-induced gastritis. Th22 cells represent a newly discovered Th cell subset, but their relevance to H. pylori-induced gastritis is unknown. DESIGN:Flow cytometry, real-time PCR and ELISA analyses were performed to examine cell, protein and transcript levels in gastric samples from patients and mice infected with H. pylori. Gastric tissues from interleukin (IL)-22-deficient and wild-type (control) mice were also examined. Tissue inflammation was determined for pro-inflammatory cell infiltration and pro-inflammatory protein production. Gastric epithelial cells and myeloid-derived suppressor cells (MDSC) were isolated, stimulated and/or cultured for Th22 cell function assays. RESULTS:Th22 cells accumulated in gastric mucosa of both patients and mice infected with H. pylori. Th22 cell polarisation was promoted via the production of IL-23 by dendritic cells (DC) during H. pylori infection, and resulted in increased inflammation within the gastric mucosa. This inflammation was characterised by the CXCR2-dependent influx of MDSCs, whose migration was induced via the IL-22-dependent production of CXCL2 by gastric epithelial cells. Under the influence of IL-22, MDSCs, in turn, produced pro-inflammatory proteins, such as S100A8 and S100A9, and suppressed Th1 cell responses, thereby contributing to the development of H. pylori-associated gastritis. CONCLUSIONS:This study, therefore, identifies a novel regulatory network involving H. pylori, DCs, Th22 cells, gastric epithelial cells and MDSCs, which collectively exert a pro-inflammatory effect within the gastric microenvironment. Efforts to inhibit this Th22-dependent pathway may therefore prove a valuable strategy in the therapy of H. pylori-associated gastritis.
The transcription factor Erg is essential for definitive hematopoiesis and the function of adult hematopoietic stem cells.
Loughran Stephen J,Kruse Elizabeth A,Hacking Douglas F,de Graaf Carolyn A,Hyland Craig D,Willson Tracy A,Henley Katya J,Ellis Sarah,Voss Anne K,Metcalf Donald,Hilton Douglas J,Alexander Warren S,Kile Benjamin T
Ets-related gene (ERG), which encodes a member of the Ets family of transcription factors, is a potent oncogene. Chromosomal rearrangements involving ERG are found in acute myeloid leukemia, acute lymphoblastic leukemia, Ewing's sarcoma and more than half of all prostate cancers; however, the normal physiological function of Erg is unknown. We did a sensitized genetic screen of the mouse for regulators of hematopoietic stem cell function and report here a germline mutation of Erg. We show that Erg is required for definitive hematopoiesis, adult hematopoietic stem cell function and the maintenance of normal peripheral blood platelet numbers.
Regulation of humoral and cellular gut immunity by lamina propria dendritic cells expressing Toll-like receptor 5.
Uematsu Satoshi,Fujimoto Kosuke,Jang Myoung Ho,Yang Bo-Gie,Jung Yun-Jae,Nishiyama Mika,Sato Shintaro,Tsujimura Tohru,Yamamoto Masafumi,Yokota Yoshifumi,Kiyono Hiroshi,Miyasaka Masayuki,Ishii Ken J,Akira Shizuo
The intestinal cell types responsible for defense against pathogenic organisms remain incompletely characterized. Here we identify a subset of CD11c(hi)CD11b(hi) lamina propria dendritic cells (LPDCs) that expressed Toll-like receptor 5 (TLR5) in the small intestine. When stimulated by the TLR5 ligand flagellin, TLR5(+) LPDCs induced the differentiation of naive B cells into immunoglobulin A-producing plasma cells by a mechanism independent of gut-associated lymphoid tissue. In addition, by a mechanism dependent on TLR5 stimulation, these LPDCs promoted the differentiation of antigen-specific interleukin 17-producing T helper cells and type 1 T helper cells. Unlike spleen DCs, the LPDCs specifically produced retinoic acid, which, in a dose-dependent way, supported the generation and retention of immunoglobulin A-producing cells in the lamina propria and positively regulated the differentiation interleukin 17-producing T helper cells. Our findings demonstrate unique properties of LPDCs and the importance of TLR5 for adaptive immunity in the intestine.
Selective Photoaffinity Probe That Enables Assessment of Cannabinoid CB Receptor Expression and Ligand Engagement in Human Cells.
Soethoudt Marjolein,Stolze Sara C,Westphal Matthias V,van Stralen Luuk,Martella Andrea,van Rooden Eva J,Guba Wolfgang,Varga Zoltan V,Deng Hui,van Kasteren Sander I,Grether Uwe,IJzerman Adriaan P,Pacher Pal,Carreira Erick M,Overkleeft Herman S,Ioan-Facsinay Andreea,Heitman Laura H,van der Stelt Mario
Journal of the American Chemical Society
Chemical tools and methods that report on G protein-coupled receptor (GPCR) expression levels and receptor occupancy by small molecules are highly desirable. We report the development of LEI121 as a photoreactive probe to study the type 2 cannabinoid receptor (CBR), a promising GPCR to treat tissue injury and inflammatory diseases. LEI121 is the first CBR-selective bifunctional probe that covalently captures CBR upon photoactivation. An incorporated alkyne serves as ligation handle for the introduction of reporter groups. LEI121 enables target engagement studies and visualization of endogenously expressed CBR in HL-60 as well as primary human immune cells using flow cytometry. Our findings show that strategically functionalized probes allow monitoring of endogenous GPCR expression and engagement in human cells using tandem photoclick chemistry and hold promise as biomarkers in translational drug discovery.
Bad targets the permeability transition pore independent of Bax or Bak to switch between Ca2+-dependent cell survival and death.
Roy Soumya Sinha,Madesh Muniswamy,Davies Erika,Antonsson Bruno,Danial Nika,Hajnóczky György
Calcium oscillations exert physiological control on mitochondrial energy metabolism and can also lead to mitochondrial membrane permeabilization and cell death. The outcome of the mitochondrial calcium signaling is altered by stress factors such as ceramide or staurosporine. However, the mechanism of this proapoptotic switch remains unclear. Using genetic, biochemical, pharmacological, and functional approaches, we here show that ceramide and staurosporine target PP2A and protein kinases A and C, respectively, in a mitochondria-associated signaling complex to induce dephosphorylation of the BH3-only protein Bad. Dephosphorylated Bad sensitizes the mitochondrial permeability transition pore (PTP) to Ca2+ through a Bcl-xL-sensitive and VDAC-mediated process. Furthermore, the Bad-induced sensitization of the PTP to Ca2+ does not require Bax or Bak. Thus, phospho-regulatory mechanisms converge on Bad to switch between the survival and apoptotic functions of mitochondrial calcium signaling by activating a mechanism whereby a BH3-only protein bypasses Bax/Bak and engages the PTP.
Regulation of Tcrb recombination ordering by c-Fos-dependent RAG deposition.
Wang Xiaoming,Xiao Gang,Zhang Yafeng,Wen Xiaomin,Gao Xiang,Okada Seiji,Liu Xiaolong
Antigen receptor variable-(diversity)-joining (V(D)J) recombination at the locus encoding the T cell antigen receptor-beta (Tcrb) is ordered, with D(beta)-to-J(beta) assembly preceding V(beta)-to-DJ(beta) joining. The molecular mechanism underlying this 'preferred' order of rearrangement remains unclear. Here we show that the D(beta) 23-base pair recombination signal sequence (D(beta) 23-RSS) contains a specific AP-1 transcription factor-binding site bound by AP-1 and its component c-Fos expressed at a specific stage. Cell-based recombination assays suggested that c-Fos interacted directly with the RAG recombinase and enhanced its deposition to D(beta) 23-RSSs, thus conferring the priority of DJ(beta) recombination. Loss of c-Fos decreased Tcrb recombination efficiency and disrupted recombination ordering in vivo. Our results show an unexpected function for c-Fos as a direct regulator of Tcrb recombination, rather than its usual function as a transcription regulator, and provide new insight into the mechanisms of recombination ordering.
Basophils enhance immunological memory responses.
Denzel Andrea,Maus Ulrich A,Rodriguez Gomez Manuel,Moll Cordula,Niedermeier Marianne,Winter Christine,Maus Regina,Hollingshead Susan,Briles David E,Kunz-Schughart Leoni A,Talke Yvonne,Mack Matthias
The cellular basis of immunological memory remains a controversial issue. Here we show that basophils bound large amounts of intact antigens on their surface and were the main source of interleukins 6 and 4 in the spleen and bone marrow after restimulation with a soluble antigen. Depletion of basophils resulted in a much lower humoral memory response and greater susceptibility of immunized mice to sepsis induced by Streptococcus pneumoniae. Adoptive transfer of antigen-reactive basophils significantly increased specific antibody production, and activated basophils, together with CD4(+) T cells, profoundly enhanced B cell proliferation and immunoglobulin production. These basophil-dependent effects on B cells required interleukins 6 and 4 and increased the capacity of CD4(+) T cells to provide B cell help. Thus, basophils are important contributors to humoral memory immune responses.
Tumour evolution inferred by single-cell sequencing.
Navin Nicholas,Kendall Jude,Troge Jennifer,Andrews Peter,Rodgers Linda,McIndoo Jeanne,Cook Kerry,Stepansky Asya,Levy Dan,Esposito Diane,Muthuswamy Lakshmi,Krasnitz Alex,McCombie W Richard,Hicks James,Wigler Michael
Genomic analysis provides insights into the role of copy number variation in disease, but most methods are not designed to resolve mixed populations of cells. In tumours, where genetic heterogeneity is common, very important information may be lost that would be useful for reconstructing evolutionary history. Here we show that with flow-sorted nuclei, whole genome amplification and next generation sequencing we can accurately quantify genomic copy number within an individual nucleus. We apply single-nucleus sequencing to investigate tumour population structure and evolution in two human breast cancer cases. Analysis of 100 single cells from a polygenomic tumour revealed three distinct clonal subpopulations that probably represent sequential clonal expansions. Additional analysis of 100 single cells from a monogenomic primary tumour and its liver metastasis indicated that a single clonal expansion formed the primary tumour and seeded the metastasis. In both primary tumours, we also identified an unexpectedly abundant subpopulation of genetically diverse 'pseudodiploid' cells that do not travel to the metastatic site. In contrast to gradual models of tumour progression, our data indicate that tumours grow by punctuated clonal expansions with few persistent intermediates.
HIV-1 infection impairs the bronchoalveolar T-cell response to mycobacteria.
Kalsdorf Barbara,Scriba Thomas J,Wood Kathryn,Day Cheryl L,Dheda Keertan,Dawson Rodney,Hanekom Willem A,Lange Christoph,Wilkinson Robert J
American journal of respiratory and critical care medicine
RATIONALE:The risk of developing active tuberculosis in persons with latent Mycobacterium tuberculosis infection is substantially increased shortly after HIV-1 seroconversion. Immune responses in the lung are important to restrict the growth of M. tuberculosis to prevent the development of disease. OBJECTIVES:To investigate innate and adaptive immune responses to M. tuberculosis in bronchoalveolar lavage from HIV-1-infected persons without active tuberculosis. METHODS:Peripheral blood was drawn and bronchoalveolar lavage (BAL) performed on healthy, HIV-1-uninfected (n = 21) and HIV-1-infected (n = 15) adults. Growth of M. tuberculosis was assessed in monocytes and alveolar macrophages. Cytokine expression by mycobacteria-specific CD4 and CD8 T cells was measured by intracellular cytokine staining or IFN-gamma ELISpot. MEASUREMENTS AND MAIN RESULTS:Mycobacterial growth in monocytes or alveolar macrophages from HIV-1-infected and -uninfected persons did not differ. Total CD4 T-cell frequencies in BAL were lower in HIV-1-infected than in HIV-1-uninfected persons (P < 0.001). Mycobacteria (bacillus Calmette-Guérin)-specific CD4 T-cell responses in BAL were severely impaired: Frequencies of cells expressing IFN-gamma or tumor necrosis factor (TNF)-alpha, as well as polyfunctional cells, expressing IFN-gamma, TNF-alpha, and IL-2 together, were lower in HIV-1-infected persons than in uninfected controls (P < 0.01 for all). CONCLUSIONS:In addition to a total CD4 T-cell deficit, the function of mycobacteria-specific CD4 T cells is significantly impaired in the lung of HIV-1-infected persons, which may account for the HIV-1-associated elevated risk for developing tuberculosis.
Osteoclastogenesis during infective exacerbations in patients with cystic fibrosis.
Shead Elizabeth F,Haworth Charles S,Gunn Elaine,Bilton Diana,Scott Mike A,Compston Juliet E
American journal of respiratory and critical care medicine
RATIONALE:Adults with cystic fibrosis (CF) are at increased risk of developing osteoporosis. During infective exacerbations, increased production of proinflammatory cytokines and markers of bone resorption have been reported. OBJECTIVE:The aim of this study is to investigate the growth and proliferation of potential osteoclast precursor cells before, during, and after intravenous antibiotic treatment of infective exacerbations in patients with CF. METHODS:Hematopoietic precursor cell growth was examined using colony formation assays using Methocult culture medium. Circulating potential osteoclast precursors were identified using four-color flow cytometry by CD14, CD33, CD34, and CD45 expression. RESULTS:At the start of an infective exacerbation increases in hematopoietic precursor colony formation (15.42 colonies/10(5) cells plated, p = 0.025), proliferation (28.5%, p < 0.001), and the numbers of circulating potential osteoclast precursors (6.5%, p < 0.001) were seen in comparison with baseline levels. These increases declined after treatment with intravenous antibiotics to a level close to baseline. CONCLUSIONS:The results demonstrate an increase in the production of potential osteoclast precursors in the peripheral blood during CF infective exacerbations. This may result in increased bone resorption and contribute to bone loss in patients with CF.
Global protein stability profiling in mammalian cells.
Yen Hsueh-Chi Sherry,Xu Qikai,Chou Danny M,Zhao Zhenming,Elledge Stephen J
Science (New York, N.Y.)
The abundance of cellular proteins is determined largely by the rate of transcription and translation coupled with the stability of individual proteins. Although we know a great deal about global transcript abundance, little is known about global protein stability. We present a highly parallel multiplexing strategy to monitor protein turnover on a global scale by coupling flow cytometry with microarray technology to track the stability of individual proteins within a complex mixture. We demonstrated the feasibility of this approach by measuring the stability of approximately 8000 human proteins and identifying proteasome substrates. The technology provides a general platform for proteome-scale analysis of protein turnover under various physiological and disease conditions.
Globally distributed uncultivated oceanic N2-fixing cyanobacteria lack oxygenic photosystem II.
Zehr Jonathan P,Bench Shellie R,Carter Brandon J,Hewson Ian,Niazi Faheem,Shi Tuo,Tripp H James,Affourtit Jason P
Science (New York, N.Y.)
Biological nitrogen (N2) fixation is important in controlling biological productivity and carbon flux in the oceans. Unicellular N2-fixing cyanobacteria have only recently been discovered and are widely distributed in tropical and subtropical seas. Metagenomic analysis of flow cytometry-sorted cells shows that unicellular N2-fixing cyanobacteria in "group A" (UCYN-A) lack genes for the oxygen-evolving photosystem II and for carbon fixation, which has implications for oceanic carbon and nitrogen cycling and raises questions regarding the evolution of photosynthesis and N2 fixation on Earth.
The p47 GTPase Lrg-47 (Irgm1) links host defense and hematopoietic stem cell proliferation.
Feng Carl G,Weksberg David C,Taylor Gregory A,Sher Alan,Goodell Margaret A
Cell stem cell
Hematopoietic stem cells (HSCs) are self-renewing bone marrow cells that give rise to all blood lineages and retain a remarkable capacity to proliferate in response to insult. Although some controls on HSC activation are known, little is understood about how this process is linked to natural signals. We report that the interferon-inducible GTPase Lrg-47 (Irgm1), previously shown to play a critical role in host defense, inhibits baseline HSC proliferation and is required for a normal HSC response to chemical and infectious stimuli. Overproliferating Lrg-47(-/-) HSCs are severely impaired in functional repopulation assays, and when challenged with hematopoietic ablation by 5-fluorouracil or infection with Mycobacterium avium, Lrg-47(-/-) mice fail to achieve the expected expansion response in stem and progenitor cell populations. Our results establish a link between the response to infection and HSC activation and demonstrate a novel function for a member of the p47 GTPase family.
Antibodies to surface dopamine-2 receptor and N-methyl-D-aspartate receptor in the first episode of acute psychosis in children.
Pathmanandavel Karrnan,Starling Jean,Merheb Vera,Ramanathan Sudarshini,Sinmaz Nese,Dale Russell C,Brilot Fabienne
BACKGROUND:The dopamine and glutamate hypotheses are well known in psychosis. Recently, the detection of autoantibodies against proteins expressed on the surface of cells in the central nervous system has raised the possibility that specific immune-mediated mechanisms may define a biological subgroup within psychosis, although no cohort of a first episode of psychosis in children has been investigated. METHODS:Serum taken during the acute presentation of 43 children with first episode of psychosis and serum from 43 pediatric control subjects was assessed for the presence of immunoglobulin (Ig)G, IgM, or IgA antibodies to dopamine-2 receptor (D2R) and NR1 subunit of the N-methyl-D-aspartate receptor using a flow cytometry live cell-based assay and immunolabeling of murine primary neurons. RESULTS:Using a cutoff of three SD above the control mean, serum antibodies to D2R or NR1 were detected in 8 of 43 psychotic patients but not detected in any of 43 control subjects (p < .001). Positive immunoglobulin binding to D2R was found in 3 of 43 psychosis patients (3 IgG, 1 IgM, 0 IgA) and to N-methyl-D-aspartate receptor in 6 of 43 patients (5 IgG, 1 IgM, 1 IgA). Specificity of antibody was confirmed by immunoaffinity purification and immunoabsorption. Significant differences in antibody binding to live, fixed, and fixed and permeabilized neurons were observed, confirming that only live cells can define surface epitope immunolabeling. CONCLUSIONS:This is the first report of serum antibodies to surface D2R and NR1 in pediatric patients with isolated psychosis, which supports the hypothesis that a subgroup of patients may be immune-mediated.
Chemical Control over Cellular Uptake of Organic Nanoparticles by Fine Tuning Surface Functional Groups.
Bai Yugang,Xing Hang,Wu Peiwen,Feng Xinxin,Hwang Kevin,Lee Jennifer M,Phang Xin Yi,Lu Yi,Zimmerman Steven C
The functional groups displayed on the surface of nanoparticles (NP) are known to play an important role in NP cellular uptake. However, only a few systematic studies have been reported to address their role, in large part because of the difficulty in regularly varying the number and structure of the functional groups on the NP surface. We employ a bottom-up strategy for the synthesis of water-soluble organic nanoparticles (ONPs) with different sizes and functional groups, using readily available monomers. Utilizing flow cytometry, we measured the HeLa cell uptake efficiency of ONPs that contain side-chains with a different (a) length, (b) number of hydroxyl groups, and (c) number of methyl groups. We have also investigated ONPs with the same functional groups but different sizes. The potential formation and influence of protein corona was examined using the same approach but in the presence of serum. The results demonstrate that under both serum and serum-free conditions the surface-exposed functional groups determine the efficiency of cellular uptake of the particles, and that the trend can be partially predicted by the lipophilicity of the polymeric ONP's repeating units. Also, by using a "masking" strategy, these particles' cellular uptake behavior could be altered conveniently.
Extracellular matrix scaffold for cardiac repair.
Robinson Keith A,Li Jinshen,Mathison Megumi,Redkar Alka,Cui Jianhua,Chronos Nicolas A F,Matheny Robert G,Badylak Stephen F
BACKGROUND:Heart failure remains a significant problem. Tissue-engineered cardiac patches offer potential to treat severe heart failure. We studied an extracellular matrix scaffold for repairing the infarcted left ventricle. METHODS AND RESULTS:Pigs (n=42) underwent left ventricular (LV) infarction. At 6 to 8 weeks, either 4-layer multilaminate urinary bladder-derived extracellular matrix or expanded polytetrafluoroethlyene (ePTFE) was implanted as full-thickness LV wall patch replacement. At 1-week, 1-month, or 3-month intervals, pigs were terminated. After macroscopic examination, samples of tissue were prepared for histology, immunocytochemistry, and analysis of cell proportions by flow cytometry. One-week and 1-month patches were intact with thrombus and inflammation; at 1 month, there was also tissue with spindle-shaped cells in proteoglycan-rich and collagenous matrix. More alpha-smooth muscle actin-positive cells were present in urinary bladder matrix (UBM) than in ePTFE (22.2+/-3.3% versus 8.4+/-2.7%; P=0.04). At 3 months, UBM was bioresorbed, and a collagen-rich vascularized tissue with numerous myofibroblasts was present. Isolated regions of alpha-sarcomeric actin-positive, intensely alpha-smooth muscle actin-immunopositive, and striated cells were observed. ePTFE at 3 months had foreign-body response with necrosis and calcification. Flow cytometry showed similarities of cells from UBM to normal myocardium, whereas ePTFE had limited cardiomyocyte markers. CONCLUSIONS:Appearance of a fibrocellular tissue that included contractile cells accompanied biodegradation of UBM when implanted as an LV-free wall infarction patch. UBM appears superior to synthetic material for cardiac patching and trends toward myocardial replacement at 3 months.
Efficient siRNA delivery into primary cells by a peptide transduction domain-dsRNA binding domain fusion protein.
Eguchi Akiko,Meade Bryan R,Chang Yung-Chi,Fredrickson Craig T,Willert Karl,Puri Nitin,Dowdy Steven F
RNA interference (RNAi) induced by short interfering RNA (siRNA) allows for discovery research and large-scale screening; however, owing to their size and anionic charge, siRNAs do not readily enter cells. Current approaches do not deliver siRNAs into a high percentage of primary cells without cytotoxicity. Here we report an efficient siRNA delivery approach that uses a peptide transduction domain-double-stranded RNA-binding domain (PTD-DRBD) fusion protein. DRBDs bind to siRNAs with high avidity, masking the siRNA's negative charge and allowing PTD-mediated cellular uptake. PTD-DRBD-delivered siRNA induced rapid RNAi in a large percentage of various primary and transformed cells, including T cells, human umbilical vein endothelial cells and human embryonic stem cells. We observed no cytotoxicity, minimal off-target transcriptional changes and no induction of innate immune responses. Thus, PTD-DRBD-mediated siRNA delivery allows efficient gene silencing in difficult-to-transfect primary cell types.
Thymus-derived leukemia-lymphoma in mice transgenic for the Tax gene of human T-lymphotropic virus type I.
Hasegawa Hideki,Sawa Hirofumi,Lewis Martha J,Orba Yasuko,Sheehy Noreen,Yamamoto Yoshie,Ichinohe Takeshi,Tsunetsugu-Yokota Yasuko,Katano Harutaka,Takahashi Hidehiro,Matsuda Junichiro,Sata Tetsutaro,Kurata Takeshi,Nagashima Kazuo,Hall William W
Adult T-cell leukemia-lymphoma (ATLL) is a group of T-cell malignancies caused by infection with human T-lymphotropic virus type I (HTLV-I). Although the pathogenesis of ATLL remains incompletely understood, the viral regulatory protein Tax is centrally involved in cellular transformation. Here we describe the generation of HTLV-I Tax transgenic mice using the Lck proximal promoter to restrict transgene expression to developing thymocytes. After prolonged latency periods, transgenic mice developed diffuse large-cell lymphomas and leukemia with clinical, pathological and immunological features characteristic of acute ATLL. Transgenic mice were functionally immunocompromised and they developed opportunistic infections. Fulminant disease also developed rapidly in SCID mice after engraftment of lymphomatous cells from transgenic mice. Flow cytometry showed that the cells were CD4(-) and CD8(-), but CD44(+), CD25(+) and cytoplasmic CD3(+). This phenotype is indicative of a thymus-derived pre-T-cell phenotype, and disease development was associated with the constitutive activation of NF-kappaB. Our model accurately reproduces human disease and will provide a tool for analysis of the molecular events in transformation and for the development of new therapeutics.
Specific CD8 T cells in IgE-mediated allergy correlate with allergen dose and allergic phenotype.
Aguilar-Pimentel Juan A,Alessandrini Francesca,Huster Katharina M,Jakob Thilo,Schulz Holger,Behrendt Heidrun,Ring Johannes,de Angelis Martin Hrabé,Busch Dirk H,Mempel Martin,Ollert Markus
American journal of respiratory and critical care medicine
RATIONALE:Studies in humans and rodents have indicated a causative role for CD8(+) T cells in IgE-mediated allergic inflammation, but their function is still controversial. OBJECTIVES:To analyze the role of allergen-specific CD8(+) T cells during the development of allergic airway inflammation in two parallel but diverging outcome models. METHODS:We used H2-Kb SIINFEKL (OVA(257-264)) multimers to analyze induction, natural distribution, and phenotype of allergen-specific CD8(+) T cells in a murine C57BL/6 model of ovalbumin (OVA)-induced allergic airway inflammation using low-dose or high-dose OVA sensitization. MEASUREMENTS AND MAIN RESULTS:The low-dose protocol was characterized by a significant induction of total and OVA-specific IgE, eosinophilic airway inflammation, IL-4 levels in bronchoalveolar lavage fluid. And significant alterations in lung function. The high dose protocol was characterized by a significant reduction of the allergic phenotype. Using OVA(257-264) H2-Kb multimers, we observed lung and airway infiltrating OVA-specific CD8(+) T cells showing an effector/effector-memory phenotype. The high-dose protocol caused significantly higher infiltration of allergen-specific CD8(+) cells to the airways and enhanced their cytotoxicity. Adoptive transfer with CD8(+) T cells from transgenic OT-I mice to TAP1(-/-) or wild-type mice showed their migration to the lungs and TAP1-dependent proliferation after OVA-aerosol exposure. TAP1(-/-) mice defective in CD8(+) T cells showed exacerbated symptoms in the low-dose sensitization model. CONCLUSIONS:Allergen-specific CD8(+) T cells seem to protect from allergic inflammation in the lungs. Their number, which is dependent on the sensitization dose, appears to be a critical predictor for the severity of the allergic phenotype.
Monolayered mesenchymal stem cells repair scarred myocardium after myocardial infarction.
Miyahara Yoshinori,Nagaya Noritoshi,Kataoka Masaharu,Yanagawa Bobby,Tanaka Koichi,Hao Hiroyuki,Ishino Kozo,Ishida Hideyuki,Shimizu Tatsuya,Kangawa Kenji,Sano Shunji,Okano Teruo,Kitamura Soichiro,Mori Hidezo
Mesenchymal stem cells are multipotent cells that can differentiate into cardiomyocytes and vascular endothelial cells. Here we show, using cell sheet technology, that monolayered mesenchymal stem cells have multipotent and self-propagating properties after transplantation into infarcted rat hearts. We cultured adipose tissue-derived mesenchymal stem cells characterized by flow cytometry using temperature-responsive culture dishes. Four weeks after coronary ligation, we transplanted the monolayered mesenchymal stem cells onto the scarred myocardium. After transplantation, the engrafted sheet gradually grew to form a thick stratum that included newly formed vessels, undifferentiated cells and few cardiomyocytes. The mesenchymal stem cell sheet also acted through paracrine pathways to trigger angiogenesis. Unlike a fibroblast cell sheet, the monolayered mesenchymal stem cells reversed wall thinning in the scar area and improved cardiac function in rats with myocardial infarction. Thus, transplantation of monolayered mesenchymal stem cells may be a new therapeutic strategy for cardiac tissue regeneration.
KIR3DL1 Allelic Polymorphism and HLA-B Epitopes Modulate Response to Anti-GD2 Monoclonal Antibody in Patients With Neuroblastoma.
Forlenza Christopher J,Boudreau Jeanette E,Zheng Junting,Le Luduec Jean-Benoît,Chamberlain Elizabeth,Heller Glenn,Cheung Nai-Kong V,Hsu Katharine C
Journal of clinical oncology : official journal of the American Society of Clinical Oncology
PURPOSE:In patients with neuroblastoma (NB), treatment with anti-GD2 monoclonal antibody (mAb) directs natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity (ADCC) against tumor cells. However, tumor cytotoxicity is attenuated by ligation of inhibitory killer immunoglobulin-like receptors (KIRs) by HLA class I molecules. KIR3DL1 polymorphism influences its ability to engage HLA-Bw4 ligands. We tested the hypothesis that poorly interacting combinations of KIR3DL1 and HLA ligands are more permissive of mAb-mediated antitumor effect. METHODS:KIR3DL1 and HLA-B subtyping were performed with a multiplex intermediate-resolution polymerase chain reaction assay for a cohort of 245 patients who were treated with antibody 3F8 for high-risk NB. Patient outcomes were analyzed according to expected degree of interaction between KIR3DL1 and HLA-B subtypes and grouped as strong, weak, or noninteractors. A comparison of NK response to 3F8 mAb opsonized NB cells between strong- and noninteracting donors was performed by flow cytometry. RESULTS:KIR3DL1 and HLA-B subtype combinations associated with noninteraction as a result of lack of receptor expression [KIR3DL1(-)], failure of interaction with inhibitory ligands [KIR3DS1(+)], or absence of KIR ligands resulted in significantly improved overall and progression-free survival. Patients with KIR3DL1 and HLA-B subtype combinations that were predictive of weak interaction had superior outcomes compared with those that were predictive of strong interaction; however, both groups were inferior to those with noninteracting subtype combinations. In vitro analysis of 3F8-mediated ADCC showed that KIR3DL1(-) and 3DS1(+) NK cells were insensitive to inhibition by HLA-Bw4-expressing NB targets. CONCLUSION:We conclude that KIR3LD1 and HLA-B allele combinations can have a prognostic impact on patient survival after treatment with anti-GD2 mAb that relies on NK-ADCC. The survival advantage seen in noninteracting combinations supports the therapeutic disinhibition of individuals with strongly interacting KIR and ligand pairs.
Type 3 innate lymphoid cells producing IL-17 and IL-22 are expanded in the gut, in the peripheral blood, synovial fluid and bone marrow of patients with ankylosing spondylitis.
Ciccia Francesco,Guggino Giuliana,Rizzo Aroldo,Saieva Laura,Peralta Sergio,Giardina AnnaRita,Cannizzaro Alessandra,Sireci Guido,De Leo Giacomo,Alessandro Riccardo,Triolo Giovanni
Annals of the rheumatic diseases
BACKGROUND:The aim of the study was to better characterise the immunological origin and the behaviour of interleukin (IL)-23-responsive innate lymphoid cells (ILCs) in the gut, synovial fluid (SF) and bone marrow (BM) of patients with ankylosing spondylitis (AS). METHODS:ILC1, ILC2 and ILC3 cells were determined and characterised by confocal microscopy and flow cytometry in ileal and BM biopsies, in peripheral blood (PB) and SF mononuclear cells obtained from patients with AS and controls. Mucosal vascular addressin cell adhesion molecule 1 (MADCAM-1), IL-7, IL-15 and aggregates of lymphoid tissue inducer cells (LTi) were evaluated by immunohistochemistry. The in vitro ability of epithelial cells in driving the differentiation of ILC3 and the effect of tumour necrosis factor inhibitors (TNFi) on the frequency of ILC3 and the expression of MADCAM1 were also assessed. RESULTS:ILC3 characterised as Lyn(-)RORc(-)Tbet(+) NKp44(+) cells were significantly expanded in the gut, SF and BM of patients with AS compared with controls, produced high levels of IL-17 and IL-22 and expressed α4β7. MADcAM1 was overexpressed in BM and ileal high endothelial venules. IL-7 was significantly increased in AS gut, especially in the context of Paneth cells, and accompanied by the presence of aggregates of c-kit/IL-7R(+) cells (LTi). In in vitro experiments, epithelial cells from patients with AS actively induced differentiation of ILC3 from LTi. TNFi efficacy was accompanied by a significant decrease in the percentage of intestinal and circulating ILC3 and in the expression of MADCAM1. CONCLUSIONS:Gut-derived IL-17(+) and IL-22(+)ILC3 are expanded in the peripheral blood, SF and inflamed BM of patients with AS, suggesting the presence of an active homing axis between the gut and the inflamed sacroiliac joints.
Repeat cycles of rituximab on clinical relapse in ANCA-associated vasculitis: identifying B cell biomarkers for relapse to guide retreatment decisions.
Md Yusof Md Yuzaiful,Vital Edward M,Das Sudipto,Dass Shouvik,Arumugakani Gururaj,Savic Sinisa,Rawstron Andrew C,Emery Paul
Annals of the rheumatic diseases
OBJECTIVE:To assess clinical and B cell biomarkers to predict relapse after rituximab in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) using retreatment on clinical relapse strategy. METHODS:35 patients with AAV received treatment with 2×1000 mg rituximab, repeated on clinical relapse (up to 5 cycles). Disease activity was assessed by Birmingham Vasculitis Activity Score (BVAS) and peripheral B cell subsets using highly sensitive flow cytometry (HSFC) as previously described; both performed at baseline and every 3 months. RESULTS:Response rates were high: >83%, with median time-to-relapse of 82 weeks for cycle 1 (C1) and >54 weeks for all cycles. Prior to rituximab, AAV was characterised by naïve B-lymphopenia compared to healthy controls. This dysregulation was more marked in patients with raised C-reactive protein (CRP) (p<0.05). In C1, no clinical feature predicted relapse. However, repopulation of naïve B cell at 6 months was associated with a reduced risk of relapse (HR: 0.326, 95% 0.114 to 0.930, p=0.036). Relapse rates at 12 and 18 months were 0% and 14% with naïve repopulation at 6 months, and 31% and 54% without naïve repopulation. CONCLUSIONS:Responses to B cell depletion therapy are long-lasting and relapse post-treatment may be predicted by absence of naïve B cell repopulation at 6 months. Naïve B-lymphopenia may be a biomarker of disease activity in AAV.
Live cell imaging to understand monocyte, macrophage, and dendritic cell function in atherosclerosis.
McArdle Sara,Mikulski Zbigniew,Ley Klaus
The Journal of experimental medicine
Intravital imaging is an invaluable tool for understanding the function of cells in healthy and diseased tissues. It provides a window into dynamic processes that cannot be studied by other techniques. This review will cover the benefits and limitations of various techniques for labeling and imaging myeloid cells, with a special focus on imaging cells in atherosclerotic arteries. Although intravital imaging is a powerful tool for understanding cell function, it alone does not provide a complete picture of the cell. Other techniques, such as flow cytometry and transcriptomics, must be combined with intravital imaging to fully understand a cell's phenotype, lineage, and function.
Proinflammatory modulation of the surface and cytokine phenotype of monocytes in patients with acute Charcot foot.
Uccioli Luigi,Sinistro Anna,Almerighi Cristiana,Ciaprini Chiara,Cavazza Antonella,Giurato Laura,Ruotolo Valeria,Spasaro Francesca,Vainieri Erika,Rocchi Giovanni,Bergamini Alberto
OBJECTIVE:Despite increased information on the importance of an inappropriate inflammatory response in the acute Charcot process, there has been no previous attempt to define the specific pathways that mediate its pathogenesis. Here, the role played by monocytes was analyzed. RESEARCH DESIGN AND METHODS:The immune phenotype of peripheral monocytes was studied by fluorescence-activated cell sorter analysis comparing patients with acute Charcot (n = 10) in both the active and recovered phase, diabetic patients with neuropathy (with or without osteomyelitis), and normal control subjects. RESULTS:When compared with diabetic control subjects and healthy subjects, monocytes from acute Charcot patients showed a proinflammatory immune phenotype characterized by increased production of proinflammatory cytokines, reduced secretion of anti-inflammatory cytokines, increased expression of surface costimulatory molecules, and increased resistance to serum withdrawal-induced apoptosis. In addition, the pattern of circulating cytokines confirmed activation of proinflammatory cytokines. No modulation of the monocyte phenotype was documented in diabetic control subjects and healthy subjects, thus indicating that the proinflammatory alterations of monocytes are specific and causative of acute Charcot. CONCLUSIONS:Together, these data provide evidence for the role of proinflammatory changes in the immune phenotype of monocytes in the pathogenesis of acute Charcot. These alterations may explain the abnormally intense and prolonged inflammatory response that characterizes this disorder and may represent a potential therapeutic target for specific pharmacological interventions.
A comprehensive strategy enabling high-resolution functional analysis of the yeast genome.
Breslow David K,Cameron Dale M,Collins Sean R,Schuldiner Maya,Stewart-Ornstein Jacob,Newman Heather W,Braun Sigurd,Madhani Hiten D,Krogan Nevan J,Weissman Jonathan S
Functional genomic studies in Saccharomyces cerevisiae have contributed enormously to our understanding of cellular processes. Their full potential, however, has been hampered by the limited availability of reagents to systematically study essential genes and the inability to quantify the small effects of most gene deletions on growth. Here we describe the construction of a library of hypomorphic alleles of essential genes and a high-throughput growth competition assay to measure fitness with unprecedented sensitivity. These tools dramatically increase the breadth and precision with which quantitative genetic analysis can be performed in yeast. We illustrate the value of these approaches by using genetic interactions to reveal new relationships between chromatin-modifying factors and to create a functional map of the proteasome. Finally, by measuring the fitness of strains in the yeast deletion library, we addressed an enigma regarding the apparent prevalence of gene dispensability and found that most genes do contribute to growth.
Transparent adult zebrafish as a tool for in vivo transplantation analysis.
White Richard Mark,Sessa Anna,Burke Christopher,Bowman Teresa,LeBlanc Jocelyn,Ceol Craig,Bourque Caitlin,Dovey Michael,Goessling Wolfram,Burns Caroline Erter,Zon Leonard I
Cell stem cell
The zebrafish is a useful model for understanding normal and cancer stem cells, but analysis has been limited to embryogenesis due to the opacity of the adult fish. To address this, we have created a transparent adult zebrafish in which we transplanted either hematopoietic stem/progenitor cells or tumor cells. In a hematopoiesis radiation recovery assay, transplantation of GFP-labeled marrow cells allowed for striking in vivo visual assessment of engraftment from 2 hr-5 weeks posttransplant. Using FACS analysis, both transparent and wild-type fish had equal engraftment, but this could only be visualized in the transparent recipient. In a tumor engraftment model, transplantation of RAS-melanoma cells allowed for visualization of tumor engraftment, proliferation, and distant metastases in as little as 5 days, which is not seen in wild-type recipients until 3 to 4 weeks. This transparent adult zebrafish serves as the ideal combination of both sensitivity and resolution for in vivo stem cell analyses.
Infection of Hepatocytes With HCV Increases Cell Surface Levels of Heparan Sulfate Proteoglycans, Uptake of Cholesterol and Lipoprotein, and Virus Entry by Up-regulating SMAD6 and SMAD7.
Zhang Fang,Sodroski Catherine,Cha Helen,Li Qisheng,Liang T Jake
BACKGROUND & AIMS:The signaling molecule and transcriptional regulator SMAD6, which inhibits the transforming growth factor β signaling pathway, is required for infection of hepatocytes by hepatitis C virus (HCV). We investigated the mechanisms by which SMAD6 and another inhibitory SMAD (SMAD7) promote HCV infection in human hepatoma cells and hepatocytes. METHODS:We infected Huh7 and Huh7.5.1 cells and primary human hepatocytes with Japanese fulminant hepatitis-1 (JFH1) HCV cell culture system (HCVcc). We then measured HCV binding, intracellular levels of HCV RNA, and expression of target genes. We examined HCV entry in HepG2/microRNA (miR) 122/CD81 cells, which support entry and replication of HCV, were transfected these cells with small interfering RNAs targeting inhibitory SMADs to analyze gene expression profiles. Uptake of labeled low-density lipoprotein (LDL) and cholesterol was measured. Cell surface proteins were quantified by flow cytometry. We obtained liver biopsy samples from 69 patients with chronic HCV infection and 19 uninfected individuals (controls) and measured levels of syndecan 1 (SDC1), SMAD7, and SMAD6 messenger RNAs (mRNAs). RESULTS:Small interfering RNA knockdown of SMAD6 blocked the binding and infection of hepatoma cell lines and primary human hepatocytes by HCV, whereas SMAD6 overexpression increased HCV infection. We found levels of mRNAs encoding heparan sulfate proteoglycans (HSPGs), particularly SDC1 mRNA, and cell surface levels of heparan sulfate to be reduced in cells after SMAD6 knockdown. SMAD6 knockdown also reduced transcription of genes encoding lipoprotein and cholesterol uptake receptors, including the LDL receptor (LDLR), the very LDLR, and the scavenger receptor class B member 1 in hepatocytes; knockdown of SMAD6 also inhibited cell uptake of cholesterol and lipoprotein. Overexpression of SMAD6 increased the expression of these genes. Similar effects were observed with knockdown and overexpression of SMAD7. In addition, HCV infection of cells increased the expression of SMAD6, which required the activity of nuclear factor-κB, but not transforming growth factor β. Liver tissues from patients with chronic HCV infection had significantly higher levels of SMAD6, SMAD7, and HSPG mRNAs than controls. CONCLUSIONS:In studies of hepatoma cell lines and primary human hepatocytes, we found that infection with HCV leads to activation of nuclear factor-κB, resulting in increased expression of SMAD6 and SMAD7. Up-regulation of SMAD6 and SMAD7 induces the expression of HSPGs, such as SDC1, as well as LDLR, very LDLR, and the scavenger receptor class B member 1, which promote HCV entry and propagation, as well as cellular uptake of cholesterol and lipoprotein.
Rectal Delivery of a DNAzyme That Specifically Blocks the Transcription Factor GATA3 and Reduces Colitis in Mice.
Popp Vanessa,Gerlach Katharina,Mott Stefanie,Turowska Agnieszka,Garn Holger,Atreya Raja,Lehr Hans-Anton,Ho I-Cheng,Renz Harald,Weigmann Benno,Neurath Markus F
BACKGROUND & AIMS:GATA3 is a transcription factor that regulates T-cell production of cytokines. We investigated the role of GATA3 in development of colitis in mice. METHODS:We performed quantitative polymerase chain reaction and immunofluorescence analyses of colon tissues from patients with Crohn's disease (n = 61) or ulcerative colitis (UC, n = 74) or from patients without inflammatory bowel diseases (n = 22), to measure levels of GATA3. Colitis was induced by administration of oxazolone or 2,4,6-trinitrobenzenesulfonic acid to control mice, mice with T-cell-specific deletion of GATA3, and mice with deletion of tumor necrosis factor receptor (TNFR) 1 and TNFR2 (TNFR double knockouts); some mice were given a GATA3-specific DNAzyme (hgd40) or a control DNAzyme via intrarectal administration, or systemic injections of an antibody to TNF before or during sensitization and challenge phase of colitis induction. Colon tissues were collected and immunofluorescence and histochemical analyses were performed. Lamina propria mononuclear cells and T cells were isolated and analyzed by flow cytometry or cytokine assays. Colonic distribution of labeled DNAzyme and inflammation were monitored by in vivo imaging (endoscopy) of mice. RESULTS:Levels of GATA3 messenger RNA were higher in colon tissues from patients with UC, but not ileal Crohn's disease, than control tissues; levels of GATA3 correlated with levels of inflammatory cytokines (interleukin [IL] 9, IL17A, IL6, IL5, IL4, IL13, and TNF). We observed increased expression of GATA3 by lamina propria T cells from mice with colitis compared with controls. Mice with T-cell-specific deletion of GATA3 did not develop colitis and their colonic tissues did not produce inflammatory cytokines (IL6, IL9, or IL13). The DNAzyme hgd40 inhibited expression of GATA3 messenger RNA by unstimulated and stimulated T cells, and distributed throughout the inflamed colons of mice with colitis. Colon tissues from mice given hgd40 had reduced expression of GATA3 messenger RNA, compared with mice given a control DNAzyme. Mice given hgd40 did not develop colitis after administration of oxazolone or 2,4,6-trinitrobenzenesulfonic acid; lamina propria cells from these mice expressed lower levels of IL6, IL9, and IL13 than cells from mice given the control DNAzyme. Mini-endoscopic images revealed that hgd40 and anti-TNF reduced colon inflammation over 3 days; hgd40 reduced colitis in TNFR double-knockout mice. CONCLUSIONS:Levels of GATA3 are increased in patients with UC and correlate with production of inflammatory cytokines in mice and humans. A DNAzyme that prevents expression of GATA3 reduces colitis in mice, independently of TNF, and reduces levels of cytokines in the colon. This DNAzyme might be developed for treatment of patients with UC.
Carbamylated Low-Density Lipoproteins Induce a Prothrombotic State Via LOX-1: Impact on Arterial Thrombus Formation In Vivo.
Holy Erik W,Akhmedov Alexander,Speer Thimoteus,Camici Giovanni G,Zewinger Stephen,Bonetti Nicole,Beer Jürg H,Lüscher Thomas F,Tanner Felix C
Journal of the American College of Cardiology
BACKGROUND:Carbamylation alters low-density lipoprotein (LDL) structure and is thought to promote vascular inflammation and dysfunction in patients with chronic kidney disease (CKD). OBJECTIVES:This study sought to determine whether carbamylated LDL (cLDL) exerts prothrombotic effects in vascular cells and platelets and whether cLDL enhances arterial thrombus formation in vivo. METHODS:LDL was isolated from healthy subjects or patients with CKD by sequential ultracentrifugation. Ex vivo carbamylation of LDL from healthy subjects was induced with potassium cyanate. Arterial thrombus formation was analyzed in a murine carotid artery photochemical injury model. Protein expression and mRNA levels were analyzed by Western blotting, flow cytometry, and real-time PCR. Platelet aggregation was measured by impedance aggregometry. RESULTS:Intravenous administration of cLDL in mice accelerated arterial thrombus formation compared to treatment with native LDL (nLDL) or vehicle. Tissue lysates of mouse carotid arteries revealed that cLDL induced the expression of TF, PAI-1, and LOX-1 mRNA in vascular cells. In human aortic smooth muscle and endothelial cells, cLDL induced TF and PAI-1 expression. In contrast, nLDL had no effect on either cell type. While nLDL and cLDL had no aggregatory effect on resting platelets, cLDL enhanced platelet aggregation in response to different agonists. This effect was mediated by mitogen-activated protein kinase p38 phosphorylation and LOX-1 translocation to the surface. LDL isolated from patients with CKD mimicked the prothrombotic effects of cLDL on vascular cells, platelets, and thrombus formation in vivo. CONCLUSIONS:We found that cLDL induces prothrombotic effects in vascular cells and platelets by activation of the LOX-1 receptor and enhances thrombus formation in vivo. This observation reveals a new mechanism underlying the increased incidence of acute thrombotic events observed in patients with CKD and may lead to the development of new lipid-targeting therapies in this population.
Monitoring DNA replication in fission yeast by incorporation of 5-ethynyl-2'-deoxyuridine.
Hua Hui,Kearsey Stephen E
Nucleic acids research
We report procedures to allow incorporation and detection of 5-ethynyl-2'-deoxyuridine (EdU) in fission yeast, a thymidine analogue which has some technical advantages over use of bromodeoxyuridine. Low concentrations of EdU (1 µM) are sufficient to allow detection of incorporation in cells expressing thymidine kinase and human equilibrative nucleoside transporter 1 (hENT1). However EdU is toxic and activates the rad3-dependent checkpoint, resulting in cell cycle arrest, potentially limiting its applications for procedures which require labelling over more than one cell cycle. Limited DNA synthesis, when elongation is largely blocked by hydroxyurea, can be readily detected by EdU incorporation using fluorescence microscopy. Thus EdU should be useful for detecting early stages of S phase, or DNA synthesis associated with DNA repair and recombination.
Antisense Bcl-2 oligonucleotide uptake in human transitional cell carcinoma.
Duggan B J,Cotter F E,Kelly J D,Hamilton P W,McCallion K,Harkin D,Gardiner T,Anderson N,Keane P F,Johnston S R,Williamson K E
OBJECTIVES:Antisense oligonucleotides (AO) downregulate Bcl-2 protein expression in various tumours if good target cell uptake is achieved. In this study, uptake of FITC labelled AO (FITC-AO) directed at Bcl-2 was examined in: (1) the RT4 bladder tumour cell line; (2) normal pig urothelium, and (3) human superficial bladder tumours. METHODS:In the RT4 cell line, uptake of FITC-AO, FITC-scrambled and FITC-sense oligonucleotides were quantified by flow cytometry at 4-hour intervals over 24 h. Uptake of FITC-AO was assessed in normal pig urothelium by flow cytometry after FITC-AO was infused for 1 h. Uptake of FITC AO was assessed in samples from 14 human superficial bladder tumours which were maintained in an ex vivo model. In samples from 6 tumours, uptake at 4 h was assessed using fluorescence microscopy. In samples from 8 separate tumours uptake every 4 h within the first 24-hour incubation period was assessed by flow cytometry. RESULTS:In the RT4 cell line the FITC-AO, FITC-scrambled and FITC-sense oligonucleotide uptake was similar. Disaggregated cells from the normal urothelium of the 3 pigs exhibited 33, 46 and 51% of cells staining positively for FITC-AO as determined by flow cytometry. All 6 tumour samples had detectable intracellular FITC-AO by fluorescence microscopy at 4 h. In the 8 tumours examined over the 24-hour incubation period, there was a range of percentages of positively staining cells. However, most tumours had a monotonic increase in intracellular fluorescence intensity that plateaued 16 h post-infusion. CONCLUSION:Antisense Bcl-2 oligonucleotides were readily taken up by superficial bladder cancer cells but the heterogeneous uptake in tumour samples needs to be considered when assessing the bioavailability of these drugs.
Mesalazine and thymoquinone attenuate intestinal tumour development in Msh2(loxP/loxP) Villin-Cre mice.
Kortüm Benedikt,Campregher Christoph,Lang Michaela,Khare Vineeta,Pinter Matthias,Evstatiev Rayko,Schmid Gerald,Mittlböck Martina,Scharl Theresa,Kucherlapati Melanie H,Edelmann Winfried,Gasche Christoph
OBJECTIVE:Lynch syndrome is caused by germline mutations in DNA mismatch repair genes leading to microsatellite instability (MSI) and colorectal cancer. Mesalazine, commonly used for the treatment of UC, reduces MSI in vitro. Here, we tested natural compounds for such activity and applied mesalazine and thymoquinone in a Msh2(loxP/loxP) Villin-Cre mouse model for Lynch syndrome. DESIGN:Flow cytometry was used for quantitation of mutation rates at a CA13 microsatellite in human colon cancer (HCT116) cells that had been stably transfected with pIREShyg2-enhanced green fluorescent protein/CA13, a reporter for frameshift mutations. Mice were treated for 43 weeks with mesalazine, thymoquinone or control chow. Intestines were analysed for tumour incidence, tumour multiplicity and size. MSI testing was performed from microdissected normal intestinal or tumour tissue, compared with mouse tails and quantified by the number of mutations per marker (NMPM). RESULTS:Besides mesalazine, thymoquinone significantly improved replication fidelity at 1.25 and 2.5 µM in HCT116 cells. In Msh2(loxP/loxP) Villin-Cre mice, tumour incidence was reduced by mesalazine from 94% to 69% (p=0.04) and to 56% (p=0.003) by thymoquinone. The mean number of tumours was reduced from 3.1 to 1.4 by mesalazine (p=0.004) and to 1.1 by thymoquinone (p<0.001). Interestingly, MSI was reduced in normal intestinal tissue from 1.5 to 1.2 NMPM (p=0.006) and to 1.1 NMPM (p=0.01) by mesalazine and thymoquinone, respectively. Thymoquinone, but not mesalazine, reduced MSI in tumours. CONCLUSIONS:Mesalazine and thymoquinone reduce tumour incidence and multiplicity in Msh2(loxP/loxP) Villin-Cre mice by reduction of MSI independent of a functional mismatch repair system. Both substances are candidate compounds for chemoprevention in Lynch syndrome mutation carriers.
Recovery of multipotent progenitors from the peripheral blood of patients requiring extracorporeal membrane oxygenation support.
Bui Kim Chi T,Senadheera Dinithi,Wang Xingchao,Hendrickson Benjamin,Friedlich Philippe,Lutzko Carolyn
American journal of respiratory and critical care medicine
RATIONALE:Studies have demonstrated that bone marrow-derived cells can be recruited to injured lungs through an unknown mechanism. We hypothesize that marrow progenitors are mobilized into the circulation of patients with cardiac and/or respiratory failure, and may then traffic to and incorporate into the sites of tissue injury. OBJECTIVES:To determine whether progenitor populations are increased in the blood of patients with severe acute cardiorespiratory failure placed on extracorporeal membrane oxygenation (ECMO). METHODS:Mononuclear cells from ECMO, umbilical cord, and control blood samples were evaluated in colony-forming assays for hematopoietic, mesenchymal, and epithelial cells. Progenitors were identified by proliferative and differentiative capacities, and confirmed by the expression of lineage-specific markers. MEASUREMENTS AND MAIN RESULTS:Significantly higher levels of hematopoietic progenitors were observed in ECMO (n = 41) samples than neonatal intensive care unit (n = 16) or pediatric intensive care unit controls (n = 14). Hematopoietic progenitor mobilization increased with time on ECMO support. Mesenchymal progenitors (MSC) were recovered from 18/58 ECMO samples with rapid sample processing (< 4 h) critical to their recovery. MSC were not recovered from normal controls. ECMO-derived MSC had osteogenic, chondrogenic, and adipogenic differentiation potential. The recovery of MSC did not influence survival outcome (61%). Epithelial progenitors were observed in eight ECMO samples but not in control samples. Their presence was associated with a lower survival trend (38%). CONCLUSIONS:Hematopoietic, mesenchymal, and epithelial progenitors were mobilized into the circulation of patients on ECMO. This may reflect a response to severe cardiopulmonary injury, blood-foreign surface interactions with the ECMO circuit, and/or hemodilution.
Serum amyloid A regulates granulomatous inflammation in sarcoidosis through Toll-like receptor-2.
Chen Edward S,Song Zhimin,Willett Matthew H,Heine Shannon,Yung Rex C,Liu Mark C,Groshong Steve D,Zhang Ying,Tuder Rubin M,Moller David R
American journal of respiratory and critical care medicine
RATIONALE:The critical innate immune mechanisms that regulate granulomatous inflammation in sarcoidosis are unknown. Because the granuloma-inducing component of sarcoidosis tissues has physicochemical properties similar to those of amyloid fibrils, we hypothesized that host proteins capable of forming poorly soluble aggregates or amyloid regulate inflammation in sarcoidosis. OBJECTIVES:To determine the role of the amyloid precursor protein, serum amyloid A, as an innate regulator of granulomatous inflammation in sarcoidosis. METHODS:Serum amyloid A expression was determined by immunohistochemistry in sarcoidosis and control tissues and by ELISA. The effect of serum amyloid A on nuclear factor (NF)-kappaB induction, cytokine expression, and Toll-like receptor-2 stimulation was determined with transformed human cell lines and bronchoalveolar lavage cells from patients with sarcoidosis. The effects of serum amyloid A on regulating helper T cell type 1 (Th1) granulomatous inflammation were determined in experimental models of sarcoidosis, using Mycobacterium tuberculosis catalase-peroxidase. MEASUREMENTS AND MAIN RESULTS:We found that the intensity of expression and distribution of serum amyloid A within sarcoidosis granulomas was unlike that in many other granulomatous diseases. Serum amyloid A localized to macrophages and giant cells within sarcoidosis granulomas but correlated with CD3(+) lymphocytes, linking expression to local Th1 responses. Serum amyloid A activated NF-kappaB in Toll-like receptor-2-expressing human cell lines; regulated experimental Th1-mediated granulomatous inflammation through IFN-gamma, tumor necrosis factor, IL-10, and Toll-like receptor-2; and stimulated production of tumor necrosis factor, IL-10, and IL-18 in lung cells from patients with sarcoidosis, effects inhibited by blocking Toll-like receptor-2. CONCLUSIONS:Serum amyloid A is a constituent and innate regulator of granulomatous inflammation in sarcoidosis through Toll-like receptor-2, providing a mechanism for chronic disease and new therapeutic targets.
Toll-like receptor triggering augments activation of human mast cells by anti-citrullinated protein antibodies.
Suurmond J,Rivellese F,Dorjée A L,Bakker A M,Rombouts Y J P C,Rispens T,Wolbink G,Zaldumbide A,Hoeben R C,Huizinga T W J,Toes R E M
Annals of the rheumatic diseases
OBJECTIVE:Mast cells may play a role in rheumatoid arthritis (RA), but activation of human mast cells in autoimmune settings has been little studied. Toll-like receptors (TLR) and Fcγ receptors (FcγR) are important receptors for cellular activation in the joint, but expression and stimulation of these receptors in human mast cells or the functional interplay between these pathways is poorly understood. Here, we analysed triggering of human mast cells via these receptors in the context of anti-citrullinated protein antibody-positive (ACPA+) RA. METHODS:RNA and protein expression of TLRs and FcγR was quantified using PCR and flow cytometry, respectively. Mast cells were stimulated with TLR ligands (including HSP70) combined with IgG immune complexes and IgG-ACPA. RESULTS:Human mast cells expressed TLRs and produced cytokines in response to TLR ligands. Both cultured and synovial mast cells expressed FcγRIIA, and triggering of this receptor by IgG immune complexes synergised with activation by TLR ligands, leading to two- to fivefold increased cytokine levels. Mast cells produced cytokines in response to ACPA immune complexes in a citrulline-specific manner, which synergised in the presence of HSP70. CONCLUSIONS:Our data show that synovial mast cells express FcγRIIA and that mast cells can be activated by IgG-ACPA and TLR ligands. Importantly, combined stimulation via TLRs and immune complexes leads to synergy in cytokine production. These findings suggest mast cells are important targets for TLR ligands and immune complexes, and that combined activation of mast cells via these pathways greatly enhances inflammation in synovial tissue of RA patients.
Molecular profiling of cytomegalovirus-induced human CD8+ T cell differentiation.
Hertoghs Kirsten M L,Moerland Perry D,van Stijn Amber,Remmerswaal Ester B M,Yong Sila L,van de Berg Pablo J E J,van Ham S Marieke,Baas Frank,ten Berge Ineke J M,van Lier René A W
The Journal of clinical investigation
CD8+ T cells play a critical role in the immune response to viral pathogens. Persistent human cytomegalovirus (HCMV) infection results in a strong increase in the number of virus-specific, quiescent effector-type CD8+ T cells with constitutive cytolytic activity, but the molecular pathways involved in the induction and maintenance of these cells are unknown. We show here that HCMV infection induced acute and lasting changes in the transcriptomes of virus-reactive T cells collected from HCMV-seropositive patients at distinct stages of infection. Enhanced cell cycle and metabolic activity was restricted to the acute phase of the response, but at all stages, HCMV-specific CD8+ T cells expressed the Th1-associated transcription factors T-bet (TBX21) and eomesodermin (EOMES), in parallel with continuous expression of IFNG mRNA and IFN-γ-regulated genes. The cytolytic proteins granzyme B and perforin as well as the fractalkine-binding chemokine receptor CX3CR1 were found in virus-reactive cells throughout the response. During HCMV latency, virus-specific CD8+ T cells lacked the typical features of exhausted cells found in other chronic infections. Persistent effector cell traits together with the permanent changes in chemokine receptor usage of virus-specific, nonexhausted, long-lived CD8+ T cells may be crucial to maintain lifelong protection from HCMV reactivation.
Automated analysis of cellular signals from large-scale calcium imaging data.
Mukamel Eran A,Nimmerjahn Axel,Schnitzer Mark J
Recent advances in fluorescence imaging permit studies of Ca(2+) dynamics in large numbers of cells, in anesthetized and awake behaving animals. However, unlike for electrophysiological signals, standardized algorithms for assigning optically recorded signals to individual cells have not yet emerged. Here, we describe an automated sorting procedure that combines independent component analysis and image segmentation for extracting cells' locations and their dynamics with minimal human supervision. In validation studies using simulated data, automated sorting significantly improved estimation of cellular signals compared to conventional analysis based on image regions of interest. We used automated procedures to analyze data recorded by two-photon Ca(2+) imaging in the cerebellar vermis of awake behaving mice. Our analysis yielded simultaneous Ca(2+) activity traces for up to >100 Purkinje cells and Bergmann glia from single recordings. Using this approach, we found microzones of Purkinje cells that were stable across behavioral states and in which synchronous Ca(2+) spiking rose significantly during locomotion.
Minimal disseminated disease in childhood T-cell lymphoblastic lymphoma: a report from the children's oncology group.
Coustan-Smith Elaine,Sandlund John T,Perkins Sherrie L,Chen Helen,Chang Myron,Abromowitch Minnie,Campana Dario
Journal of clinical oncology : official journal of the American Society of Clinical Oncology
PURPOSE Disease dissemination to the bone marrow is detected at diagnosis in approximately 15% of children with T-cell lymphoblastic lymphoma (T-LL). It is unclear whether the remaining patients have submicroscopic systemic disease and, if so, what is the clinical significance of this finding. PATIENTS AND METHODS Using a flow cytometric method that can detect one T-LL cell among 10,000 normal cells, we examined bone marrow and peripheral-blood samples collected from 99 children with T-LL at diagnosis, as well as blood samples collected from 42 patients during treatment. Results In 71 (71.7%) of the 99 marrow samples obtained at diagnosis, T-LL cells represented 0.01% to 31.6% (median, 0.22%) of mononuclear cells; 57 of the 71 T-LL-positive samples were from patients with stage II/III disease. Results of studies in bilateral marrow aspirates were highly concordant. Two-year event-free survival (EFS) was 68.1% +/- 11.1% (SE) for patients with > or = 1% T-LL cells in bone marrow versus 90.7% +/- 4.4% for those with lower levels of marrow involvement (P = .031); EFS for patients with > or = 5% lymphoblasts was 51.9% +/- 18.0% (P = .009). T-LL cells were as prevalent in blood as in marrow; monitoring residual T-LL cells in blood during remission induction therapy identified patients with slower disease clearance. CONCLUSION More than two thirds of children with T-LL have disseminated disease at diagnosis, a proportion much higher than previously demonstrated. Measurements of disease dissemination at diagnosis might provide useful prognostic information, which can be further refined by monitoring response to therapy through blood testing.
Highly active and selective endopeptidases with programmed substrate specificities.
Varadarajan Navin,Rodriguez Sarah,Hwang Bum-Yeol,Georgiou George,Iverson Brent L
Nature chemical biology
A family of engineered endopeptidases has been created that is capable of cleaving a diverse array of peptide sequences with high selectivity and catalytic efficiency (kcat/KM > 10(40 M(- 1) s(- 1)). By screening libraries with a selection-counterselection substrate method, protease variants were programmed to recognize amino acids having altered charge, size and hydrophobicity properties adjacent to the scissile bond of the substrate, including GluArg, a specificity that to our knowledge has not been observed among natural proteases. Members of this artificial protease family resulted from a relatively small number of amino acid substitutions that (at least in one case) proved to be epistatic.
Inhibition of translation by small RNA-stabilized mRNA structures in human cells.
Ito Kenichiro,Go Sou,Komiyama Makoto,Xu Yan
Journal of the American Chemical Society
RNA-mediated gene regulation and expression are critically dependent on both nucleic acid architecture and recognition. We present a novel mechanism for the regulation of gene expression through direct RNA-RNA interactions between small RNA and mRNA in human cells. Using mRNA reporters containing G-rich sequences in the 5'-untranslated region (5'-UTR), in the coding region, or both, we showed that G-rich small RNAs bind to the reporter mRNAs and form an intermolecular RNA G-quadruplex that can inhibit gene translation in living cells. Using a combination of circular dichroism (CD) and RNase footprinting in vitro, we found that the intermolecular G-quadruplexes show a parallel G-quadruplex structure. We next investigated whether the intermolecular G-quadruplex is present in living cells. Employing the fluorophore-labeled probes, we found that two G-rich RNA molecules form an intermolecular G-quadruplex structure in living cells. These results extend the concept of small RNA-mediated expression and suggest an important role for such RNA structures in the inhibition of mRNA translation.
PCR amplification from single DNA molecules on magnetic beads in emulsion: application for high-throughput screening of transcription factor targets.
Kojima Takaaki,Takei Yoshiaki,Ohtsuka Miharu,Kawarasaki Yasuaki,Yamane Tsuneo,Nakano Hideo
Nucleic acids research
We have developed a novel method of genetic library construction on magnetic microbeads based on solid-phase single-molecule PCR in a fine and robust water-phase compartment formed in water-in-oil (w/o) emulsions. In this method, critically diluted DNA fragments were distributed over the emulsion as templates, where beads crosslinked with multiple primers and other PCR components were encapsulated to form multiple reaction compartments. The delivered DNA was then amplified and covalently immobilized on the beads in parallel, within individual compartments, to construct a genetic library on beads (GLOBE), which was readily applicable to a genomewide global scanning of genetic elements recognized by a defined DNA-binding protein. We constructed a GLOBE of Paracoccus denitrificans and selected gene beads that were bound to the His-tagged transcription factor PhaR by flow cytometry. As a result of flow cytometry screening with an anti-His fluorescent antibody, the PhaR target fragments were enriched 1200-fold from this library with this system. Therefore, this system is a powerful tool for analyzing the transcription network on a genomewide scale.
Exhaustion of CD39-Expressing CD8 T Cells in Crohn's Disease Is Linked to Clinical Outcome.
BACKGROUND & AIMS:Exhaustion of CD8 T cells has been suggested to inform different clinical outcomes in Crohn's disease, but detailed analyses are lacking. This study aimed to identify the role of exhaustion on a single-cell level and identify relevant CD8 T cell populations in Crohn's disease. METHODS:Blood and intestinal tissue from 58 patients with Crohn's disease (active disease or remission) were assessed for CD8 T cell expression of exhaustion markers and their cytokine profile by highly multiplexed flow and mass cytometry. Key disease-associated subsets were sorted and analyzed by RNA sequencing. CD39 inhibition assays were performed in vitro. RESULTS:Activated CD39 and CD39PD-1 CD8 T cell subsets expressing multiple exhaustion markers were enriched at low frequency in active Crohn's disease. Their cytokine production capacity was inversely linked to the Harvey-Bradshaw Index. Subset-level protein and transcriptome profiling revealed co-existence of effector and exhaustion programs in CD39 and CD39 PD-1CD8 T cells, with CD39 cells likely originating from the intestine. CD39 enzymatic activity controlled T cell cytokine production. Importantly, transcriptional exhaustion signatures were enriched in remission in CD39-expressing subsets with up-regulation of TOX. Subset-level transcriptomics revealed a CD39-related gene module that is associated with the clinical course. CONCLUSIONS:These data showed a role for the exhaustion of peripheral CD39-expressing CD8 T cell subsets in Crohn's disease. Their low frequency illustrated the utility of single-cell cytometry methods for identification of relevant immune populations. Importantly, the link of their exhaustion status to the clinical activity and their specific gene signatures have implications for exhaustion-based personalized medicine approaches.
The aged niche disrupts muscle stem cell quiescence.
Chakkalakal Joe V,Jones Kieran M,Basson M Albert,Brack Andrew S
The niche is a conserved regulator of stem cell quiescence and function. During ageing, stem cell function declines. To what extent and by what means age-related changes within the niche contribute to this phenomenon are unknown. Here we demonstrate that the aged muscle stem cell niche, the muscle fibre, expresses Fgf2 under homeostatic conditions, driving a subset of satellite cells to break quiescence and lose their self-renewing capacity. We show in mice that relatively dormant aged satellite cells robustly express sprouty 1 (Spry1), an inhibitor of fibroblast growth factor (FGF) signalling. Increasing FGF signalling in aged satellite cells under homeostatic conditions by removing Spry1 results in the loss of quiescence, satellite cell depletion and diminished regenerative capacity. Conversely, reducing niche-derived FGF activity through inhibition of Fgfr1 signalling or overexpression of Spry1 in satellite cells prevents their depletion. These experiments identify an age-dependent change in the stem cell niche that directly influences stem cell quiescence and function.
Aptamer-based tumor-targeted drug delivery for photodynamic therapy.
Shieh Yen-An,Yang Shu-Jyuan,Wei Ming-Feng,Shieh Ming-Jium
A specialized G-rich DNA structure, G-quadruplex, has been studied for its special physical characteristics and biological effects. Herein we report a novel strategy of using G-quadruplex as a drug carrier to target cancer cells for photodynamic therapy (PDT). A G-quadruplex forming AS1411 aptamer could be physically conjugated with six molecules of porphyrin derivative, 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP4), to fabricate the apt-TMP complex. The TMPyP4 molecules in the complex were identified to bind tightly to the aptamer by intercalation and outside binding. Because the G-quadruplex structure is known to target the overexpressed nucleolin in cancer cells, in this study, the effect of the G-quadruplex structure as a carrier for the delivery of TMPyP4 into cancer cells by nucleolin-mediated internalization was investigated. The results showed that the apt-TMP complex exhibited a higher TMPyP4 accumulation in MCF7 breast cancer cells than in M10 normal epithelium cells. After treated with light for 180 s, the photodamage in MCF7 cells was larger than in M10 cells. These results indicated that the TMPyP4 delivery and uptake were mediated by the specific interaction of the apt-TMP complex with nucleolin on the cellular surface and that the use of the AS1411 aptamer as a drug carrier may be a potential tactic in cancer therapy.
The calcium-activated nonselective cation channel TRPM4 is essential for the migration but not the maturation of dendritic cells.
Barbet Gaëtan,Demion Marie,Moura Ivan C,Serafini Nicolas,Léger Thibaut,Vrtovsnik François,Monteiro Renato C,Guinamard Romain,Kinet Jean-Pierre,Launay Pierre
Dendritic cell (DC) maturation and migration are events critical for the initiation of immune responses. After encountering pathogens, DCs upregulate the expression of costimulatory molecules and subsequently migrate to secondary lymphoid organs. Calcium (Ca(2+)) entry governs the functions of many hematopoietic cell types, but the role of Ca(2+) entry in DC biology remains unclear. Here we report that the Ca(2+)-activated nonselective cation channel TRPM4 was expressed in and controlled the Ca(2+) homeostasis of mouse DCs. The absence of TRPM4, which elicited Ca(2+) overload, did not influence DC maturation but did considerably impair chemokine-dependent DC migration. Our results establish TRPM4-regulated Ca(2+) homeostasis as crucial for DC mobility but not maturation and emphasize that DC maturation and migration are independently regulated.
ThPOK acts late in specification of the helper T cell lineage and suppresses Runx-mediated commitment to the cytotoxic T cell lineage.
Egawa Takeshi,Littman Dan R
The transcription factor ThPOK is required and sufficient for the generation of CD4(+)CD8(-) thymocytes, yet the mechanism by which ThPOK orchestrates differentiation into the CD4(+) helper T cell lineage remains unclear. Here we used reporter mice to track the expression of transcription factors in developing thymocytes. Distal promoter-driven expression of the gene encoding the transcription factor Runx3 was restricted to major histocompatibility complex (MHC) class I-selected thymocytes. In ThPOK-deficient mice, such expression was derepressed in MHC class II-selected thymocytes, which contributed to their redirection to the CD8(+) T cell lineage. In the absence of both ThPOK and Runx, redirection was prevented and cells potentially belonging to the CD4(+) lineage, presumably specified independently of ThPOK, were generated. Our results suggest that MHC class II-selected thymocytes are directed toward the CD4(+) lineage independently of ThPOK but require ThPOK to prevent Runx-dependent differentiation toward the CD8(+) lineage.
Cascading suppression of transcriptional silencers by ThPOK seals helper T cell fate.
Muroi Sawako,Naoe Yoshinori,Miyamoto Chizuko,Akiyama Kaori,Ikawa Tomokatsu,Masuda Kyoko,Kawamoto Hiroshi,Taniuchi Ichiro
CD4 and the transcription factor ThPOK are essential for the differentiation of major histocompatibility complex class II-restricted thymocytes into the helper T cell lineage; their genes (Cd4 and Zbtb7b (called 'ThPOK' here)) are repressed by transcriptional silencer elements in cytotoxic T cells. The molecular mechanisms regulating expression of these genes during helper T cell lineage differentiation remain unknown. Here we showed that inefficient upregulation of ThPOK, induced by removal of the proximal enhancer from the ThPOK locus, resulted in the transdifferentiation of helper lineage-specified cells into the cytotoxic T cell lineage. Furthermore, direct antagonism by ThPOK of the Cd4 and ThPOK silencers generated two regulatory loops that initially inhibited Cd4 downregulation and later stabilized ThPOK expression. Our results show how an initial lineage-specification signal can be amplified and stabilized during the lineage-commitment process.
Fluorescence activated cell sorting as a general ultra-high-throughput screening method for directed evolution of glycosyltransferases.
Yang Guangyu,Rich Jamie R,Gilbert Michel,Wakarchuk Warren W,Feng Yan,Withers Stephen G
Journal of the American Chemical Society
Glycosyltransferases (GTs) offer very attractive approaches to the synthesis of complex oligosaccharides. However, the limited number of available GTs, together with their instability and strict substrate specificity, have severely hampered the broad application of these enzymes. Previous attempts to broaden the range of substrate scope and to increase the activity of GTs via protein engineering have met with limited success, partially because of the lack of effective high-throughput screening methods. Recently, we reported an ultra-high-throughput screening method for sialyltransferases based on fluorescence-activated cell sorting (Aharoni et al. Nat. Methods 2006, 3, 609-614). Here, we considerably improve this method via the introduction of a two-color screening protocol to minimize the probability of false positive mutants and demonstrate its generality through directed evolution of a neutral sugar transferase, beta-1,3-galactosyltransferase CgtB. A variant with broader substrate tolerance than the wild-type enzyme and 300-fold higher activity was identified rapidly from a library of >10(7) CgtB mutants. Importantly, the variant effected much more efficient synthesis of G(M1a) and asialo G(M1) oligosaccharides, the building blocks of important therapeutic glycosphingolipids, than did the parent enzyme. This work not only establishes a new methodology for the directed evolution of galactosyltransferases, but also suggests a powerful strategy for the screening of almost all GT activities, thereby facilitating the engineering of glycosyltransferases.
Latent herpesvirus infection augments experimental pulmonary fibrosis.
Vannella Kevin M,Luckhardt Tracy R,Wilke Carol A,van Dyk Linda F,Toews Galen B,Moore Bethany B
American journal of respiratory and critical care medicine
RATIONALE:No effective treatment exists for idiopathic pulmonary fibrosis, and its pathogenesis remains unclear. Accumulating evidence implicates herpesviruses as cofactors (either initiating or exacerbating agents) of fibrotic lung disease, but a role for latent herpesvirus infection has not been studied. OBJECTIVES:To develop a murine model to determine whether latent herpesvirus infection can augment fibrotic responses and to gain insight into potential mechanisms of enhanced fibrogenesis. METHODS:Mice were infected with murine gammaherpesvirus 14 to 70 days before a fibrotic challenge with fluorescein isothiocyanate or bleomycin so that the virus was latent at the time of fibrotic challenge. Measurements were made after viral infection alone or after the establishment of fibrosis. MEASUREMENTS AND MAIN RESULTS:gammaHerpesvirus is latent by 14 days post infection, and infection 14 to 70 days before fibrotic challenge augmented fibrosis. Fibrotic augmentation was not dependent on reactivation of the latent virus to a lytic state. Total cell numbers and fibrocyte numbers were increased in the lungs of latently infected mice administered fibrotic challenge compared with mock-infected mice that received fibrotic challenge. Latent infection up-regulates expression of proinflammatory chemokines, transforming growth factor-beta1, and cysteinyl leukotrienes in alveolar epithelial cells. CONCLUSIONS:Latent gammaherpesvirus infection augments subsequent fibrotic responses in mice. Enhanced fibrosis is associated with the induction of profibrotic factors and the recruitment of fibrocytes. Our data complement existing human and animal data supporting the hypothesis that gammaherpesviruses can serve as initiating cofactors in the pathogenesis of pulmonary fibrosis.
Nanoparticle-mediated cytoplasmic delivery of proteins to target cellular machinery.
Bale Shyam Sundhar,Kwon Seok Joon,Shah Dhiral A,Banerjee Akhilesh,Dordick Jonathan S,Kane Ravi S
Despite recent advances in nanomaterial-based delivery systems, their applicability as carriers of cargo, especially proteins for targeting cellular components and manipulating cell function, is not well-understood. Herein, we demonstrate the ability of hydrophobic silica nanoparticles to deliver proteins, including enzymes and antibodies, to a diverse set of mammalian cells, including human cancer cells and rat stem cells, while preserving the activity of the biomolecule post-delivery. Specifically, we have explored the delivery and cytosolic activity of hydrophobically functionalized silica nanoparticle-protein conjugates in a human breast cancer cell line (MCF-7) and rat neural stem cells (NSCs) and elucidated the mechanism of cytosolic transport. Importantly, the proteins were delivered to the cytosol without extended entrapment in the endosomes, which facilitated the retention of biological activity of the delivered proteins. As a result, delivery of ribonuclease A (RNase A) and the antibody to phospho-Akt (pAkt) resulted in the initiation of cell death. Delivery of control protein conjugates (e.g., those containing green fluorescent protein or goat antirabbit IgG) resulted in minimal cell death, indicating that the carrier-mediated toxicity was low. The results presented here provide insight into the design of nanomaterials as protein carriers that enable control of cell function.
Human adult vena saphena contains perivascular progenitor cells endowed with clonogenic and proangiogenic potential.
Campagnolo Paola,Cesselli Daniela,Al Haj Zen Ayman,Beltrami Antonio Paolo,Kränkel Nicolle,Katare Rajesh,Angelini Gianni,Emanueli Costanza,Madeddu Paolo
BACKGROUND:Clinical trials in ischemic patients showed the safety and benefit of autologous bone marrow progenitor cell transplantation. Non-bone marrow progenitor cells with proangiogenic capacities have been described, yet they remain clinically unexploited owing to their scarcity, difficulty of access, and low ex vivo expansibility. We investigated the presence, antigenic profile, expansion capacity, and proangiogenic potential of progenitor cells from the saphenous vein of patients undergoing coronary artery bypass surgery. METHODS AND RESULTS:CD34-positive cells, negative for the endothelial marker von Willebrand factor, were localized around adventitial vasa vasorum. After dissection of the vein from surrounding tissues and enzymatic digestion, CD34-positive/CD31-negative cells were isolated by selective culture, immunomagnetic beads, or fluorescence-assisted cell sorting. In the presence of serum, CD34-positive/CD31-negative cells gave rise to a highly proliferative population that expressed pericyte/mesenchymal antigens together with the stem cell marker Sox2 and showed clonogenic and multilineage differentiation capacities. We called this population "saphenous vein-derived progenitor cells" (SVPs). In culture, SVPs integrated into networks formed by endothelial cells and supported angiogenesis through paracrine mechanisms. Reciprocally, endothelial cell-released factors facilitated SVP migration. These interactive responses were inhibited by Tie-2 or platelet-derived growth factor-BB blockade. Intramuscular injection of SVPs in ischemic limbs of immunodeficient mice improved neovascularization and blood flow recovery. At 14 days after transplantation, proliferating SVPs were still detectable in the recipient muscles, where they established N-cadherin-mediated physical contact with the capillary endothelium. CONCLUSIONS:SVPs generated from human vein CD34-positive/CD31-negative progenitor cells might represent a new therapeutic tool for angiogenic therapy in ischemic patients.
Toll-like receptor-mediated induction of type I interferon in plasmacytoid dendritic cells requires the rapamycin-sensitive PI(3)K-mTOR-p70S6K pathway.
Cao Weiping,Manicassamy Santhakumar,Tang Hua,Kasturi Sudhir Pai,Pirani Ali,Murthy Niren,Pulendran Bali
Robust production of type I interferon (IFN-alpha/beta) in plasmacytoid dendritic cells (pDCs) is crucial for antiviral immunity. Here we show involvement of the mammalian target of rapamycin (mTOR) pathway in regulating interferon production by pDCs. Inhibition of mTOR or its 'downstream' mediators, the p70 ribosomal S6 protein kinases p70S6K1 and p70S6K2, during pDC activation by Toll-like receptor 9 (TLR9) blocked the interaction of TLR9 with the adaptor MyD88 and subsequent activation of the interferon-regulatory factor IRF7, which resulted in impaired IFN-alpha/beta production. Microarray analysis confirmed that inhibition of mTOR by the immunosuppressive drug rapamycin suppressed antiviral and anti-inflammatory gene expression. Consistent with this, targeting rapamycin-encapsulated microparticles to antigen-presenting cells in vivo resulted in less IFN-alpha/beta production in response to CpG DNA or the yellow fever vaccine virus strain 17D. Thus, mTOR signaling is crucial in TLR-mediated IFN-alpha/beta responses by pDCs.
Distinct functions for the transcription factors GATA-3 and ThPOK during intrathymic differentiation of CD4(+) T cells.
Wang Lie,Wildt Kathryn F,Zhu Jinfang,Zhang Xianyu,Feigenbaum Lionel,Tessarollo Lino,Paul William E,Fowlkes B J,Bosselut Rémy
The transcription factors GATA-3 and ThPOK are required for intrathymic differentiation of CD4(+) T cells, but their precise functions in this process remain unclear. Here we show that, contrary to previous findings, Gata3 disruption blocked differentiation into the CD4(+) T cell lineage before commitment to the CD4(+) lineage and in some contexts permitted the 'redirection' of major histocompatibility complex class II-restricted thymocytes into the CD8(+) lineage. GATA-3 promoted ThPOK expression and bound to a region of the locus encoding ThPOK established as being critical for ThPOK expression. Finally, ThPOK promoted differentiation into the CD4(+) lineage in a way dependent on GATA-3 but inhibited differentiation into the CD8(+) lineage independently of GATA-3. We propose that GATA-3 acts as a specification factor for the CD4(+) lineage 'upstream' of the ThPOK-controlled CD4(+) commitment checkpoint.
Mincle is an ITAM-coupled activating receptor that senses damaged cells.
Yamasaki Sho,Ishikawa Eri,Sakuma Machie,Hara Hiromitsu,Ogata Koji,Saito Takashi
Macrophage-inducible C-type lectin (Mincle) is expressed mainly in macrophages and is induced after exposure to various stimuli and stresses. Here we show that Mincle selectively associated with the Fc receptor common gamma-chain and activated macrophages to produce inflammatory cytokines and chemokines. Mincle-expressing cells were activated in the presence of dead cells, and we identified SAP130, a component of small nuclear ribonucloprotein, as a Mincle ligand that is released from dead cells. To investigate whether Mincle is required for normal responses to cell death in vivo, we induced thymocyte death by irradiating mice and found that transient infiltration of neutrophils into the thymus could be blocked by injection of Mincle-specific antibody. Our results suggest that Mincle is a receptor that senses nonhomeostatic cell death and thereby induces the production of inflammatory cytokines to drive the infiltration of neutrophils into damaged tissue.
Regulatory T cells attenuate mycobacterial stasis in alveolar and blood-derived macrophages from patients with tuberculosis.
Semple Patricia L,Binder Anke B,Davids Malika,Maredza Alice,van Zyl-Smit Richard N,Dheda Keertan
American journal of respiratory and critical care medicine
RATIONALE:There are hardly any data about the frequency of CD4(+)CD25(+)Foxp3(+) regulatory T cells (T-Regs) in the lungs of patients with active tuberculosis (TB). OBJECTIVES:To obtain data about the frequency of CD4(+)CD25(+)Foxp3(+) T-Regs, and their impact on mycobacterial containment, in the lungs of patients with active TB. METHODS:Patients with pulmonary TB (n = 49) and healthy volunteers with presumed latent TB infection (LTBI; n = 38) donated blood and/or bronchoalveolar lavage (BAL) cells obtained by bronchoscopy. T-cell phenotype (Th1/Th2/Th17/T-Reg) and functional status was evaluated using flow-cytometry and (3)H-thymidine proliferation assays, respectively. H37Rv-infected alveolar and monocyte-derived macrophages were cocultured with autologous T-Regs and purified protein derivative (PPD) preprimed T-Reg-depleted effector cells. Mycobacterial containment was evaluated by counting CFUs. MEASUREMENTS AND MAIN RESULTS:In blood and BAL T-Reg levels were higher in TB versus LTBI (P < 0.04), and in TB the frequency of T-Regs was significantly higher in BAL versus blood (P < 0.001). T-Reg-mediated suppression of T-cell proliferation in blood and BAL was concentration-dependent. Restriction of mycobacterial growth in infected alveolar and monocyte-derived macrophages was significantly diminished, and by up to 50%, when T-Regs were cocultured with PPD-primed CD4(+) effector T cells. The levels of CD8(+) T-Regs (CD8(+)CD25(+)Foxp3(+)), IL-17-producing T-Regs (IL-17(+)CD4(+)CD25(+)Foxp3(+)), and IL-17-producing T cells were similar in BAL-TB versus BAL-LTBI. Within the TB group compartmentalization of responses was prominent (T-Reg, IFN-γ, tumor necrosis factor-α, IL-17, and IL-22 significantly higher in BAL vs. blood). CONCLUSIONS:In patients with TB the alveolar compartment is enriched for CD4(+) T-Regs. Peripheral blood-derived T-Regs decrease the ability of alveolar and monocyte-derived macrophages to restrict the growth of Mycobacterium tuberculosis in the presence of effector cells. Collectively, these data suggest that CD4(+)CD25(+)FoxP3(+) T-Regs subvert antimycobacterial immunity in human TB.
Transcriptional Profiling of Cutaneous MRGPRD Free Nerve Endings and C-LTMRs.
Reynders Ana,Mantilleri Annabelle,Malapert Pascale,Rialle Stéphanie,Nidelet Sabine,Laffray Sophie,Beurrier Corinne,Bourinet Emmanuel,Moqrich Aziz
Cutaneous C-unmyelinated MRGPRD free nerve endings and C-LTMRs innervating hair follicles convey two opposite aspects of touch sensation: a sensation of pain and a sensation of pleasant touch. The molecular mechanisms underlying these diametrically opposite functions are unknown. Here, we used a mouse model that genetically marks C-LTMRs and MRGPRD neurons in combination with fluorescent cell surface labeling, flow cytometry, and RNA deep-sequencing technology (RNA-seq). Cluster analysis of RNA-seq profiles of the purified neuronal subsets revealed 486 and 549 genes differentially expressed in MRGPRD-expressing neurons and C-LTMRs, respectively. We validated 48 MRGPD- and 68 C-LTMRs-enriched genes using a triple-staining approach, and the Ca3.3 channel, found to be exclusively expressed in C-LTMRs, was validated using electrophysiology. Our study greatly expands the molecular characterization of C-LTMRs and suggests that this particular population of neurons shares some molecular features with Aβ and Aδ low-threshold mechanoreceptors.
An autistic endophenotype results in complex immune dysfunction in healthy siblings of autistic children.
Saresella Marina,Marventano Ivana,Guerini Franca Rosa,Mancuso Roberta,Ceresa Lara,Zanzottera Milena,Rusconi Beatrice,Maggioni Emanuela,Tinelli Carmine,Clerici Mario
BACKGROUND:Endophenotypes are simple biological aspects of a disease that can be observed in unaffected relatives at a higher rate than in the general population; an "autism endophenotype" justifies the observation that a mild reduction in ideational fluency and nonverbal generativity might be observed in healthy, unaffected relatives of children with autism. Because it is becoming apparent that autism is associated with given alleles encoding within the human leukocyte antigens region, a region of pivotal importance in immunity, we examined whether the "autism endophenotype" would extend its effects on the immune system. METHODS:Multiple immune parameters were analyzed in autistic children (AC) (n = 20), their siblings (HSAC) (n = 15), and age- and gender-comparable healthy control subjects (HC) (n = 20) without any familiarity for autism. RESULTS:The immune profiles of HSAC were significantly more similar to those of their autistic siblings than to what was observed in HC. Thus, in AC and HSAC compared with HC: 1) proinflammatory and interleukin-10-producing immune cells were augmented (p < .01 in both comparisons); 2) CD8(+) naïve (CD45RA(+)/CCR7+) T lymphocytes were increased (p < .0001 and p = .001); and 3) CD8(+) effector memory (CD45RA(-)/CCR7-) (p < .0001 and p = .03) as well as CD4(+) terminally differentiated (CD45RA(-)/CCR7+) (p < .05 in both comparisons) lymphocytes were diminished. Serum autoantibodies (GM1) could be detected in 10% of AC children alone. CONCLUSIONS:Results of this pilot study indicate that a complex immune dysfunction is present both in autistic children and in their non-autistic siblings and show the presence of an "autism endophenotype" that expands its effects on immunologic functions.
Radiation-Induced DNA Damage in Operators Performing Endovascular Aortic Repair.
El-Sayed Tamer,Patel Ashish S,Cho Jun S,Kelly James A,Ludwinski Francesca E,Saha Prakash,Lyons Oliver T,Smith Alberto,Modarai Bijan,
BACKGROUND:Radiation exposure during fluoroscopically guided interventions such as endovascular aortic repair (EVAR) is a growing concern for operators. This study aimed to measure DNA damage/repair markers in operators perfoming EVAR. METHODS:Expression of the DNA damage/repair marker, γ-H2AX and DNA damage response marker, phosphorylated ataxia telangiectasia mutated (pATM), were quantified in circulating lymphocytes in operators during the peri-operative period of endovascular (infrarenal, branched, and fenestrated) and open aortic repair using flow cytometry. These markers were separately measured in the same operators but this time wearing leg lead shielding in addition to upper body protection and compared with those operating with unprotected legs. Susceptibility to radiation damage was determined by irradiating operators' blood in vitro. RESULTS:γ-H2AX and pATM levels increased significantly in operators immediately after branched endovascular aortic repair/fenestrated endovascular aortic repair (<0.0003 for both). Only pATM levels increased after infrarenal endovascular aortic repair (<0.04). Expression of both markers fell to baseline in operators after 24 hours (<0.003 for both). There was no change in γ-H2AX or pATM expression after open repair. Leg protection abrogated γ-H2AX and pATM response after branched endovascular aortic repair/fenestrated endovascular aortic repair. The expression of γ-H2AX varied significantly when operators' blood was exposed to the same radiation dose in vitro (<0.0001). CONCLUSIONS:This is the first study to detect an acute DNA damage response in operators performing fluoroscopically guided aortic procedures and highlights the protective effect of leg shielding. Defining the relationship between this response and cancer risk may better inform safe levels of chronic low-dose radiation exposure.
FACS-assisted microarray profiling implicates novel genes and pathways in zebrafish gastrointestinal tract development.
Stuckenholz Carsten,Lu Lili,Thakur Prakash,Kaminski Naftali,Bahary Nathan
BACKGROUND & AIMS:The zebrafish Danio rerio is an excellent model system for mammalian gastrointestinal development. To identify differentially regulated genes important in gastrointestinal organogenesis, we profiled the transcriptome of the zebrafish developing gastrointestinal tract. METHODS:Embryos from a transgenic zebrafish line expressing green fluorescent protein (GFP) in the developing intestine, liver, and pancreas were dissociated at 4 developmental time points, their cells sorted based on GFP expression with fluorescence-activated cell sorting (FACS), and analyzed with microarrays. To improve our analysis, we annotated the Affymetrix Zebrafish GeneChip with human orthologs. RESULTS:Transcriptional profiling showed significant differences between GFP(+) and GFP(-) cells. Up-regulated genes and pathways were consistent with mammalian gastrointestinal development, such as hepatic nuclear factor gene networks and cancer. We implicate the phosphatidylinositol 3 kinase (PI3K) pathway and show that inhibition with LY294002 causes gastrointestinal defects in zebrafish. We identified novel genes, such as the microRNAs miR-217 and miR-122, the tight junction protein claudin c, the gene fam136a, and a zebrafish tetraspanin. Novel pathways include genes containing a putative transcription factor binding sequence, GGAANCGGAANY, and a nucleolar gene network. The zebrafish microarrays also identify a set of 32 genes that may mediate the effects of gain of chromosome arm 8q in human colon, liver, and pancreatic cancers. CONCLUSIONS:We successfully combine FACS and microarray profiling to follow organogenesis throughout development. These experiments identify novel genes and pathways that probably play a role in mammalian gastrointestinal development and are potential targets for therapeutic intervention in the management of gastrointestinal disease and cancer.
Automated screening for mutants affecting dopaminergic-neuron specification in C. elegans.
Doitsidou Maria,Flames Nuria,Lee Albert C,Boyanov Alexander,Hobert Oliver
We describe an automated method to isolate mutant Caenorhabditis elegans that do not appropriately execute cellular differentiation programs. We used a fluorescence-activated sorting mechanism implemented in the COPAS Biosort machine to isolate mutants with subtle alterations in the cellular specificity of GFP expression. This methodology is considerably more efficient than comparable manual screens and enabled us to isolate mutants in which dopamine neurons do not differentiate appropriately.
Trophoblast differentiation defect in human embryonic stem cells lacking PIG-A and GPI-anchored cell-surface proteins.
Chen Guibin,Ye Zhaohui,Yu Xiaobing,Zou Jizhong,Mali Prashant,Brodsky Robert A,Cheng Linzhao
Cell stem cell
Pluripotent human embryonic stem (hES) cells can differentiate into various cell types derived from the three embryonic germ layers and extraembryonic tissues such as trophoblasts. The mechanisms governing lineage choices of hES cells are largely unknown. Here, we report that we established two independent hES cell clones lacking a group of cell surface molecules, glycosyl-phosphatidyl-inositol-anchored proteins (GPI-APs). The GPI-AP deficiency in these two hES clones is due to the deficiency in the gene expression of PIG-A (phosphatidyl-inositol-glycan class A), which is required for the first step of GPI synthesis. GPI-AP-deficient hES cells were capable of forming embryoid bodies and initiating cell differentiation into the three embryonic germ layers. However, GPI-AP-deficient hES cells failed to form trophoblasts after differentiation induction by embryoid body formation or by adding exogenous BMP4. The defect in trophoblast formation was due to the lack of GPI-anchored BMP coreceptors, resulting in the impairment of full BMP4 signaling activation in the GPI-AP-deficient hES cells. These data reveal that GPI-AP-enhanced full activation of BMP signaling is required for human trophoblast formation.
N-cadherin expression level distinguishes reserved versus primed states of hematopoietic stem cells.
Haug Jeffrey S,He Xi C,Grindley Justin C,Wunderlich Joshua P,Gaudenz Karin,Ross Jason T,Paulson Ariel,Wagner Kathryn P,Xie Yucai,Zhu Ruihong,Yin Tong,Perry John M,Hembree Mark J,Redenbaugh Erin P,Radice Glenn L,Seidel Christopher,Li Linheng
Cell stem cell
Osteoblasts expressing the homophilic adhesion molecule N-cadherin form a hematopoietic stem cell (HSC) niche. Therefore, we examined how N-cadherin expression in HSCs relates to their function. We found that bone marrow (BM) cells highly expressing N-cadherin (N-cadherin(hi)) are not stem cells, being largely devoid of a Lineage(-)Sca1(+)cKit(+) population and unable to reconstitute hematopoietic lineages in irradiated recipient mice. Instead, long-term HSCs form distinct populations expressing N-cadherin at intermediate (N-cadherin(int)) or low (N-cadherin(lo)) levels. The minority N-cadherin(lo) population can robustly reconstitute the hematopoietic system, express genes that may prime them to mobilize, and predominate among HSCs mobilized from BM to spleen. The larger N-cadherin(int) population performs poorly in reconstitution assays when freshly isolated but improves in response to overnight in vitro culture. Their expression profile and lower cell-cycle entry rate suggest N-cadherin(int) cells are being held in reserve. Thus, differential N-cadherin expression reflects functional distinctions between two HSC subpopulations.
Ontogeny and multipotency of neural crest-derived stem cells in mouse bone marrow, dorsal root ganglia, and whisker pad.
Nagoshi Narihito,Shibata Shinsuke,Kubota Yoshiaki,Nakamura Masaya,Nagai Yasuo,Satoh Etsuko,Morikawa Satoru,Okada Yohei,Mabuchi Yo,Katoh Hiroyuki,Okada Seiji,Fukuda Keiichi,Suda Toshio,Matsuzaki Yumi,Toyama Yoshiaki,Okano Hideyuki
Cell stem cell
Although recent reports have described multipotent, self-renewing, neural crest-derived stem cells (NCSCs), the NCSCs in various adult rodent tissues have not been well characterized or compared. Here we identified NCSCs in the bone marrow (BM), dorsal root ganglia, and whisker pad and prospectively isolated them from adult transgenic mice encoding neural crest-specific P0-Cre/Floxed-EGFP and Wnt1-Cre/Floxed-EGFP. Cultured EGFP-positive cells formed neurosphere-like structures that expressed NCSC genes and could differentiate into neurons, glial cells, and myofibroblasts, but the frequency of the cell types was tissue source dependent. Interestingly, we observed NCSCs in the aorta-gonad-mesonephros region, circulating blood, and liver at the embryonic stage, suggesting that NCSCs migrate through the bloodstream to the BM and providing an explanation for how neural cells are generated from the BM. The identification of NCSCs in accessible adult tissue provides a new potential source for autologous cell therapy after nerve injury or disease.
Canonical notch signaling is dispensable for the maintenance of adult hematopoietic stem cells.
Maillard Ivan,Koch Ute,Dumortier Alexis,Shestova Olga,Xu Lanwei,Sai Hong,Pross Seth E,Aster Jon C,Bhandoola Avinash,Radtke Freddy,Pear Warren S
Cell stem cell
Gain-of-function experiments have demonstrated the potential of Notch signals to expand primitive hematopoietic progenitors, but whether Notch physiologically regulates hematopoietic stem cell (HSC) homeostasis in vivo is unclear. To answer this question, we evaluated the effect of global deficiencies of canonical Notch signaling in rigorous HSC assays. Hematopoietic progenitors expressing dominant-negative Mastermind-like1 (DNMAML), a potent inhibitor of Notch-mediated transcriptional activation, achieved stable long-term reconstitution of irradiated hosts and showed a normal frequency of progenitor fractions enriched for long-term HSCs. Similar results were observed with cells lacking CSL/RBPJ, a DNA-binding factor that is required for canonical Notch signaling. Notch-deprived progenitors provided normal long-term reconstitution after secondary competitive transplantation. Furthermore, Notch target genes were expressed at low levels in primitive hematopoietic progenitors. Taken together, these results rule out an essential physiological role for cell-autonomous canonical Notch signals in HSC maintenance.
The transcription factor EGR1 controls both the proliferation and localization of hematopoietic stem cells.
Min Irene M,Pietramaggiori Giorgio,Kim Francis S,Passegué Emmanuelle,Stevenson Kristen E,Wagers Amy J
Cell stem cell
EGR1 is a member of the immediate early response transcription factor family and functions in cell growth, development, and stress responses in many tissues. Here we report an additional role for EGR1 in regulating homeostasis of hematopoietic stem cells (HSCs). HSCs normally express Egr1 at high levels, but dramatically downregulate its expression when induced to divide and migrate. Consistent with this finding, mice lacking Egr1 exhibit significant increases in steady-state levels of dividing HSCs in the bone marrow (BM), and a striking spontaneous mobilization of HSCs into the peripheral blood. These data identify EGR1 as a transcriptional regulator of stem cell migration that normally functions to promote HSC quiescence and retention in the niche. The ability of this single factor to regulate both proliferation and mobilization of HSCs suggests that EGR1 commands a genetic program that coordinates stem cell division and migration to maintain appropriate HSC number and function.
Self-Assembled Gold Nanoclusters for Bright Fluorescence Imaging and Enhanced Drug Delivery.
Yahia-Ammar Akram,Sierra Daniel,Mérola Fabienne,Hildebrandt Niko,Le Guével Xavier
Nanoparticles combining enhanced cellular drug delivery with efficient fluorescence detection are important tools for the development of theranostic agents. Here, we demonstrate this concept by a simple, fast, and robust protocol of cationic polymer-mediated gold nanocluster (Au NCs) self-assembly into nanoparticles (NPs) of ca. 120 nm diameter. An extensive characterization of the monodisperse and positively charged NPs revealed pH-dependent swelling properties, strong fluorescence enhancement, and excellent colloidal and photostability in water, buffer, and culture medium. The versatility of the preparation is demonstrated by using different Au NC surface ligands and cationic polymers. Steady-state and time-resolved fluorescence measurements give insight into the aggregation-induced emission phenomenon (AIE) by tuning the Au NC interactions in the self-assembled nanoparticles using the pH-dependent swelling. In vitro studies in human monocytic cells indicate strongly enhanced uptake of the NPs compared to free Au NCs in endocytic compartments. The NPs keep their assembly structure with quite low cytotoxicity up to 500 μg Au/mL. Enhanced drug delivery is demonstrated by loading peptides or antibodies in the NPs using a one-pot synthesis. Fluorescence microscopy and flow cytometry confirmed intracellular colocalization of the biomolecules and the NP carriers with a respective 1.7-fold and 6.5-fold enhanced cellular uptake of peptides and antibodies compared to the free biomolecules.
Altered Peripheral B-Lymphocyte Subsets in Type 1 Diabetes and Latent Autoimmune Diabetes in Adults.
Deng Chao,Xiang Yufei,Tan Tingting,Ren Zhihui,Cao Chuqing,Huang Gan,Wen Li,Zhou Zhiguang
OBJECTIVE:B lymphocytes play an important role in the immunopathogenesis of autoimmune diabetes. We hypothesized that the altered B-cell subset phenotype is associated with autoimmune diabetes. RESEARCH DESIGN AND METHODS:Patients with type 1 diabetes (T1D) (n = 81), latent autoimmune diabetes in adults (LADA) (n = 82), or type 2 diabetes (T2D) (n = 95) and healthy control subjects (n = 218) with normal glucose tolerance (NGT) were recruited. We determined the percentage of circulating B-lymphocyte subsets, including CD19(+)CD23(-)CD21(+) (marginal zone B [MZB]), CD19(+)CD23(+)CD21(-) (follicular B [FoB]), and CD19(+)CD5(+)CD1d(hi) (interleukin-10-producing regulatory B [B10]) cells by flow cytometry. RESULTS:Patients with T1D or LADA had increased percentages of MZB cells and decreased percentages of FoB cells compared with healthy control subjects with NGT and patients with T2D. Moreover, patients with T1D showed the lowest frequency of B10 cells compared with patients with LADA or T2D, whereas healthy control subjects expressed the highest frequency of B10 cells. Of note, the frequency of MZB cells was negatively associated and the frequency of FoB cells was positively associated with fasting C-peptide (FCP). The frequency of B10 cells was positively correlated with FCP and negatively correlated with hemoglobin A(1c). CONCLUSIONS:The data show that patients with T1D or LADA express an altered frequency of B-cell subsets, which is associated with islet function and glycemia. These findings suggest that B lymphocytes may be involved in loss of self-tolerance and β-cell destruction and could be used as a biomarker and potential target for immunological intervention.
Increased number and function of endothelial progenitor cells stimulate angiogenesis by resident liver sinusoidal endothelial cells (SECs) in cirrhosis through paracrine factors.
Kaur Savneet,Tripathi Dinesh,Dongre Ketki,Garg Vishal,Rooge Sheetalnath,Mukopadhyay Asok,Sakhuja Puja,Sarin Shiv K
Journal of hepatology
BACKGROUND & AIMS:Recent studies have shown a pathological role of angiogenesis in the progression of chronic liver diseases (CLDs). The present study focused on numbers and angiogenic functions of circulating endothelial progenitor cells (EPCs) in patients with cirrhosis. METHODS:Circulating EPCs were counted by flow-cytometry, and correlated with different parameters of liver disease. They were cultured in patients and controls to compare colony-formation, proliferation and tube formation. Interactions of EPCs with hepatic stellate cells (HSCs) and sinusoidal endothelial cells (SECs) were examined by indirect and direct co-cultures in presence of EPCs and EPC-conditioned medium, respectively. ELISA and inhibition assays were performed to assess the role of EPC-derived angiogenic factors. RESULTS:The number of circulating EPCs was substantially higher in cirrhotic patients compared to controls (p<0.05), and showed good correlation with hepatic disease severity. Functional assays revealed that colonies and proliferation of EPCs were significantly increased in patients compared to controls (p<0.05). Direct and indirect co-cultures of patients' EPCs showed an increase in tube formation by SECs as compared to that observed with control EPCs (p<0.05). There was, however, no tube formation in HSC-EPC co-cultures. Levels of PDGF-BB and VEGF were substantially increased in patients' EPC media and inhibition of these factors by neutralizing antibodies led to a significant reduction in SECs proliferation. CONCLUSIONS:Mobilization and proliferation of EPCs are significantly enhanced in cirrhotic patients in comparison to controls. EPCs may play an important paracrine role in liver angiogenesis by stimulating resident SECs in cirrhosis.
Mst1 controls lymphocyte trafficking and interstitial motility within lymph nodes.
Katagiri Koko,Katakai Tomoya,Ebisuno Yukihiko,Ueda Yoshihiro,Okada Takaharu,Kinashi Tatsuo
The EMBO journal
The regulation of lymphocyte adhesion and migration plays crucial roles in lymphocyte trafficking during immunosurveillance. However, our understanding of the intracellular signalling that regulates these processes is still limited. Here, we show that the Ste20-like kinase Mst1 plays crucial roles in lymphocyte trafficking in vivo. Mst1(-/-) lymphocytes exhibited an impairment of firm adhesion to high endothelial venules, resulting in an inefficient homing capacity. In vitro lymphocyte adhesion cascade assays under physiological shear flow revealed that the stopping time of Mst1(-/-) lymphocytes on endothelium was markedly reduced, whereas their L-selectin-dependent rolling/tethering and transition to LFA-1-mediated arrest were not affected. Mst1(-/-) lymphocytes were also defective in the stabilization of adhesion through alpha4 integrins. Consequently, Mst1(-/-) mice had hypotrophic peripheral lymphoid tissues and reduced marginal zone B cells and dendritic cells in the spleen, and defective emigration of single positive thymocytes. Furthermore, Mst1(-/-) lymphocytes had impaired motility over lymph node-derived stromal cells and within lymph nodes. Thus, our data indicate that Mst1 is a key enzyme involved in lymphocyte entry and interstitial migration.
Preferential association of a functional variant in complement receptor 2 with antibodies to double-stranded DNA.
Zhao Jian,Giles Brendan M,Taylor Rhonda L,Yette Gabriel A,Lough Kara M,Ng Han Leng,Abraham Lawrence J,Wu Hui,Kelly Jennifer A,Glenn Stuart B,Adler Adam J,Williams Adrienne H,Comeau Mary E,Ziegler Julie T,Marion Miranda,Alarcón-Riquelme Marta E, ,Alarcón Graciela S,Anaya Juan-Manuel,Bae Sang-Cheol,Kim Dam,Lee Hye-Soon,Criswell Lindsey A,Freedman Barry I,Gilkeson Gary S,Guthridge Joel M,Jacob Chaim O,James Judith A,Kamen Diane L,Merrill Joan T,Sivils Kathy Moser,Niewold Timothy B,Petri Michelle A,Ramsey-Goldman Rosalind,Reveille John D,Scofield R Hal,Stevens Anne M,Vilá Luis M,Vyse Timothy J,Kaufman Kenneth M,Harley John B,Langefeld Carl D,Gaffney Patrick M,Brown Elizabeth E,Edberg Jeffrey C,Kimberly Robert P,Ulgiati Daniela,Tsao Betty P,Boackle Susan A
Annals of the rheumatic diseases
OBJECTIVES:Systemic lupus erythematosus (SLE; OMIM 152700) is characterised by the production of antibodies to nuclear antigens. We previously identified variants in complement receptor 2 (CR2/CD21) that were associated with decreased risk of SLE. This study aimed to identify the causal variant for this association. METHODS:Genotyped and imputed genetic variants spanning CR2 were assessed for association with SLE in 15 750 case-control subjects from four ancestral groups. Allele-specific functional effects of associated variants were determined using quantitative real-time PCR, quantitative flow cytometry, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP)-PCR. RESULTS:The strongest association signal was detected at rs1876453 in intron 1 of CR2 (pmeta=4.2×10(-4), OR 0.85), specifically when subjects were stratified based on the presence of dsDNA autoantibodies (case-control pmeta=7.6×10(-7), OR 0.71; case-only pmeta=1.9×10(-4), OR 0.75). Although allele-specific effects on B cell CR2 mRNA or protein levels were not identified, levels of complement receptor 1 (CR1/CD35) mRNA and protein were significantly higher on B cells of subjects harbouring the minor allele (p=0.0248 and p=0.0006, respectively). The minor allele altered the formation of several DNA protein complexes by EMSA, including one containing CCCTC-binding factor (CTCF), an effect that was confirmed by ChIP-PCR. CONCLUSIONS:These data suggest that rs1876453 in CR2 has long-range effects on gene regulation that decrease susceptibility to lupus. Since the minor allele at rs1876453 is preferentially associated with reduced risk of the highly specific dsDNA autoantibodies that are present in preclinical, active and severe lupus, understanding its mechanisms will have important therapeutic implications.
Ibrutinib and Venetoclax for First-Line Treatment of CLL.
Jain Nitin,Keating Michael,Thompson Philip,Ferrajoli Alessandra,Burger Jan,Borthakur Gautam,Takahashi Koichi,Estrov Zeev,Fowler Nathan,Kadia Tapan,Konopleva Marina,Alvarado Yesid,Yilmaz Musa,DiNardo Courtney,Bose Prithviraj,Ohanian Maro,Pemmaraju Naveen,Jabbour Elias,Sasaki Koji,Kanagal-Shamanna Rashmi,Patel Keyur,Jorgensen Jeffrey,Garg Naveen,Wang Xuemei,Sondermann Katrina,Cruz Nichole,Wei Chongjuan,Ayala Ana,Plunkett William,Kantarjian Hagop,Gandhi Varsha,Wierda William
The New England journal of medicine
BACKGROUND:Ibrutinib, an inhibitor of Bruton's tyrosine kinase, and venetoclax, an inhibitor of B-cell lymphoma 2 protein, have been approved for patients with chronic lymphocytic leukemia (CLL). Preclinical investigations have indicated potential synergistic interaction of their combination. METHODS:We conducted an investigator-initiated phase 2 study of combined ibrutinib and venetoclax involving previously untreated high-risk and older patients with CLL. All patients had at least one of the following features: chromosome 17p deletion, mutated , chromosome 11q deletion, unmutated , or an age of 65 years or older. Patients received ibrutinib monotherapy (420 mg once daily) for 3 cycles, followed by the addition of venetoclax (weekly dose escalation to 400 mg once daily). Combined therapy was administered for 24 cycles. Response assessments were performed according to International Workshop on Chronic Lymphocytic Leukemia 2008 criteria. Minimal residual disease was assessed by means of multicolor flow cytometry in bone marrow (sensitivity, 10). RESULTS:A total of 80 patients were treated. The median age was 65 years (range, 26 to 83). A total of 30% of the patients were 70 years of age or older. Overall, 92% of the patients had unmutated , aberration, or chromosome 11q deletion. With combined treatment, the proportions of patients who had complete remission (with or without normal blood count recovery) and remission with undetectable minimal residual disease increased over time. After 12 cycles of combined treatment, 88% of the patients had complete remission or complete remission with incomplete count recovery, and 61% had remission with undetectable minimal residual disease. Responses were noted in older adults and across all high-risk subgroups. Three patients had laboratory evidence of tumor lysis syndrome. The adverse-event profile was similar to what has been reported with ibrutinib and venetoclax. CONCLUSIONS:In this study, combined venetoclax and ibrutinib was an effective oral regimen for high-risk and older patients with CLL. (Funded by AbbVie and others; ClinicalTrials.gov number, NCT02756897.).
Detection of promoter activity by flow cytometric analysis of GFP reporter expression.
Ducrest Anne-Lyse,Amacker Mario,Lingner Joachim,Nabholz Markus
Nucleic acids research
Low efficiency of transfection is often the limiting factor for acquiring conclusive data in reporter assays. It is especially difficult to efficiently transfect and characterize promoters in primary human cells. To overcome this problem we have developed a system in which reporter gene expression is quantified by flow cytometry. In this system, green fluorescent protein (GFP) reporter constructs are co-transfected with a reference plasmid that codes for the mouse cell surface antigen Thy-1.1 and serves to determine transfection efficiency. Comparison of mean GFP expression of the total transfected cell population with the activity of an analogous luciferase reporter showed that the sensitivity of the two reporter systems is similar. However, because GFP expression can be analyzed at the single-cell level and in the same cells the expression of the reference plasmid can be monitored by two-color fluorescence, the GFP reporter system is in fact more sensitive, particularly in cells which can only be transfected with a low efficiency.
Increase of CD4+ CD25+ regulatory T-cells in the liver of patients with hepatocellular carcinoma.
Yang Xiu Hua,Yamagiwa Satoshi,Ichida Takafumi,Matsuda Yasunobu,Sugahara Satoshi,Watanabe Hisami,Sato Yoshinobu,Abo Toru,Horwitz David A,Aoyagi Yutaka
Journal of hepatology
BACKGROUND/AIMS:The immune response to tumor-specific antigens is typically unable to control the growth and spread of malignant cells. Accumulating evidence indicates that the suppressive effects of CD4+ CD25+ regulatory T-cells are at least partially responsible for the failure of immune-mediated elimination of tumor cells. METHODS:We have studied 25 patients with hepatocellular carcinoma (HCC). The liver tissues with HCC were separated into the marginal region of tumor (peri-tumor region) and the non-tumor region distant from the tumor. CD4+ CD25+ T-cells were quantified in the blood and the liver by flow cytometry and immunohistochemistry, and their effect on T-cell proliferation and activation was determined. RESULTS:We found a significant increase in both the proportion and absolute numbers of CD4+ CD25+ T-cells in the peri-tumor regions, but not in unaffected areas (9.5 +/- 4.5 vs. 4.6 +/- 2.8%, P = 0.011). CD4+ CD25+ T-cells isolated from peri-tumor regions displayed phenotype markers characteristic of regulatory T-cells, and expressed Foxp3 mRNA. CD8+ T-cells in peri-tumor regions were inversely proportional to CD4+ CD25+ T-cells in the same region (P < 0.001). Moreover, isolated CD4+ CD25+ T-cells inhibited autologous CD8+ T-cell proliferation. CONCLUSIONS:Our results suggest that CD4+ CD25+ T-cells in the marginal region of HCC may play a critical role in controlling CD8+ cytotoxic T-cell activity and, thereby, contribute to the progression of HCC.
Deletion of Notch1 converts pro-T cells to dendritic cells and promotes thymic B cells by cell-extrinsic and cell-intrinsic mechanisms.
Feyerabend Thorsten B,Terszowski Grzegorz,Tietz Annette,Blum Carmen,Luche Hervé,Gossler Achim,Gale Nicholas W,Radtke Freddy,Fehling Hans Jörg,Rodewald Hans-Reimer
Notch1 signaling is required for T cell development and has been implicated in fate decisions in the thymus. We showed that Notch1 deletion in progenitor T cells (pro-T cells) revealed their latent developmental potential toward becoming conventional and plasmacytoid dendritic cells. In addition, Notch1 deletion in pro-T cells resulted in large numbers of thymic B cells, previously explained by T-to-B cell fate conversion. Single-cell genotyping showed, however, that the majority of these thymic B cells arose from Notch1-sufficient cells by a cell-extrinsic pathway. Fate switching nevertheless exists for a subset of thymic B cells originating from Notch1-deleted pro-T cells. Chimeric mice lacking the Notch ligand delta-like 4 (Dll4) in thymus epithelium revealed an essential role for Dll4 in T cell development. Thus, Notch1-Dll4 signaling fortifies T cell commitment by suppressing non-T cell lineage potential in pro-T cells, and normal Notch1-driven T cell development repels excessive B cells in the thymus.
Foxp3-dependent microRNA155 confers competitive fitness to regulatory T cells by targeting SOCS1 protein.
Lu Li-Fan,Thai To-Ha,Calado Dinis Pedro,Chaudhry Ashutosh,Kubo Masato,Tanaka Kentaro,Loeb Gabriel B,Lee Hana,Yoshimura Akihiko,Rajewsky Klaus,Rudensky Alexander Y
Foxp3(+) regulatory T (Treg) cells limit pathogenic immune responses to self-antigens and foreign antigens. An essential role for microRNA (miRNA) in the maintenance and function of Treg cells, revealed by the Treg cell-specific Dicer ablation, raised a question as to a specific miRNA contribution. We found that Foxp3 controlled the elevated miR155 expression required for maintaining Treg cell proliferative activity and numbers under nonlymphopenic conditions. Moreover, miR155 deficiency in Treg cells resulted in increased suppressor of cytokine signaling 1 (SOCS1) expression accompanied by impaired activation of signal transducer and activator of transcription 5 (STAT5) transcription factor in response to limiting amounts of interleukin-2. Our studies suggest that Foxp3-dependent regulation of miR155 maintains competitive fitness of Treg cell subsets by targeting SOCS1, and they provide experimental support for a proposed role for miRNAs in ensuring the robustness of cellular phenotypes.
MicroRNA 301A Promotes Intestinal Inflammation and Colitis-Associated Cancer Development by Inhibiting BTG1.
He Chong,Yu Tianming,Shi Yan,Ma Caiyun,Yang Wenjing,Fang Leilei,Sun Mingming,Wu Wei,Xiao Fei,Guo Feifan,Chen Minhu,Yang Hong,Qian Jiaming,Cong Yingzi,Liu Zhanju
BACKGROUND & AIMS:Intestinal tissues from patients with inflammatory bowel disease (IBD) and colorectal cancer have increased expression of microRNA-301a (MIR301A) compared with tissues from patients without IBD. We studied the mechanisms of MIR301A in the progression of IBD in human tissues and mice. METHODS:We isolated intestinal epithelial cells (IECs) from biopsy samples of the colon from 153 patients with different stages of IBD activity, 6 patients with colitis-associated cancer (CAC), and 35 healthy individuals (controls), enrolled in the study in Shanghai, China. We measured expression of MIR301A and BTG anti-proliferation factor 1 (BTG1) by IECs using quantitative reverse-transcription polymerase chain reaction. Human colon cancer cell lines (HCT-116 and SW480) were transfected with a lentivirus that expresses MIR301A; expression of cytokines and tight junction proteins were measured by quantitative reverse transcription polymerase chain reaction, flow cytometry, and immunofluorescence staining. We generated mice with disruption of the microRNA-301A gene (MIR301A-knockout mice), and also studied mice that express a transgene-encoding BTG1. Colitis was induced in knockout, transgenic, and control (C57BL/B6) mice by administration of dextran sulfate sodium (DSS), and mice were given azoxymethane to induce colorectal carcinogenesis. Colons were collected and analyzed histologically and by immunohistochemistry; tumor nodules were counted and tumor size was measured. SW480 cells expressing the MIR301A transgene were grown as xenograft tumors in nude mice. RESULTS:Expression of MIR301A increased in IECs from patients with IBD and CAC compared with controls. MIR301A-knockout mice were resistant to the development of colitis following administration of DSS; their colon tissues expressed lower levels of interleukin 1β (IL1β), IL6, IL8, and tumor necrosis factor than colons of control mice. Colon tissues from MIR301A-knockout mice had increased epithelial barrier integrity and formed fewer tumors following administration of azoxymethane than control mice. Human IECs expressing transgenic MIR301A down-regulated expression of cadherin 1 (also called E-cadherin or CDH1). We identified BTG1 mRNA as a target of MIR301A; levels of BTG1 mRNA were reduced in inflamed mucosa from patients with active IBD compared with controls. There was an inverse correlation between levels of BTG1 mRNA and levels of MIR301A in inflamed mucosal tissues from patients with active IBD. Human colon cancer cell lines that expressed a MIR301A transgene increased proliferation; they had increased permeability and decreased expression of CDH1 compared with cells transfected with a control vector, indicating reduced intestinal barrier function. BTG1 transgenic mice developed less severe colitis than control mice following administration of DSS. SW480 cells expressing anti-MIR301A formed fewer xenograft tumors in nude mice than cells expressing a control vector. CONCLUSIONS:Levels of MIR301A are increased in IECs from patients with active IBD. MIR301A reduces expression of BTG1 to reduce epithelial integrity and promote inflammation in mouse colon and promotes tumorigenesis. Strategies to decrease levels of MIR301A in colon tissues might be developed to treat patients with IBD and CAC.
Pericardial Adipose Tissue Regulates Granulopoiesis, Fibrosis, and Cardiac Function After Myocardial Infarction.
Horckmans Michael,Bianchini Mariaelvy,Santovito Donato,Megens Remco T A,Springael Jean-Yves,Negri Irene,Vacca Michele,Di Eusanio Marco,Moschetta Antonio,Weber Christian,Duchene Johan,Steffens Sabine
BACKGROUND:The pericardial adipose tissue (AT) contains a high density of lymphoid clusters. It is unknown whether these clusters play a role in post-myocardial infarction (MI) inflammatory responses and cardiac outcome. METHODS:Lymphoid clusters were examined in epicardial AT of humans with or without coronary artery disease. Murine pericardial lymphoid clusters were visualized in mice subjected to coronary artery ligation. To study the relevance of pericardial clusters during inflammatory responses after MI, we surgically removed the pericardial AT and performed B-cell depletion and granulocyte-macrophage colony-stimulating factor blockade. Leukocytes in murine hearts, pericardial AT, spleen, mediastinal lymph nodes, and bone marrow were quantified by flow cytometry. Cannabinoid receptor CB2 (CB2) mice were used as a model for enhanced B-cell responses. The effect of impaired dendritic cell (DC) trafficking on pericardial AT inflammatory responses was tested in CCR7 mice subjected to MI. Cardiac fibrosis and ventricular function were assessed by histology and echocardiography. RESULTS:We identified larger B-cell clusters in epicardial AT of human patients with coronary artery disease in comparison with controls without coronary artery disease. Infarcted mice also had larger pericardial clusters and 3-fold upregulated numbers of granulocyte-macrophage colony-stimulating factor-producing B cells within pericardial AT, but not spleen or lymph nodes. This was associated with higher DC and T-cell counts in pericardial AT, which outnumbered DCs and T cells in lymph nodes. Analysis of DC maturation markers, tracking experiments with fluorescently labeled cells, and use of CCR7-deficient mice suggested that activated DCs migrate from infarcts into pericardial AT via CCR7. B-cell depletion or granulocyte-macrophage colony-stimulating factor neutralization inhibited DC and T-cell expansion within pericardial AT, and translated into reduced bone marrow granulopoiesis and cardiac neutrophil infiltration 3 days after MI. The relevance of the pericardial AT in mediating all these effects was confirmed by removal of pericardial AT and ex vivo coculture with pericardial AT and granulocyte progenitors. Finally, enhanced fibrosis and worsened ejection fraction in CB2 mice were limited by pericardial AT removal. CONCLUSIONS:Our findings unveil a new mechanism by which the pericardial AT coordinates immune cell activation, granulopoiesis, and outcome after MI.
Late developmental plasticity in the T helper 17 lineage.
Lee Yun Kyung,Turner Henrietta,Maynard Craig L,Oliver James R,Chen Dongquan,Elson Charles O,Weaver Casey T
Development of T helper (Th) 17 cells requires transforming growth factor (TGF)-beta and interleukin (IL)-6 and is independent of the Th1 pathway. Although T cells that produce interferon (IFN)-gamma are a recognized feature of Th17 cell responses, mice deficient for STAT4 and T-bet-two prototypical Th1 transcription factors-are protected from autoimmunity associated with Th17 pathogenesis. To examine the fate and pathogenic potential of Th17 cells and origin of IFN-gamma-producing T cells that emerge during Th17 immunity, we developed IL-17F reporter mice that identify cells committed to expression of IL-17F and IL-17A. Th17 cells required TGF-beta for sustained expression of IL-17F and IL-17A. In the absence of TGF-beta, both IL-23 and IL-12 acted to suppress IL-17 and enhance IFN-gamma production in a STAT4- and T-bet-dependent manner, albeit with distinct efficiencies. These results support a model of late Th17 developmental plasticity with implications for autoimmunity and host defense.
Differential roles of interleukin-17A and -17F in host defense against mucoepithelial bacterial infection and allergic responses.
Ishigame Harumichi,Kakuta Shigeru,Nagai Takeshi,Kadoki Motohiko,Nambu Aya,Komiyama Yutaka,Fujikado Noriyuki,Tanahashi Yuko,Akitsu Aoi,Kotaki Hayato,Sudo Katsuko,Nakae Susumu,Sasakawa Chihiro,Iwakura Yoichiro
Interleukin-17A (IL-17A) is a cytokine produced by T helper 17 (Th17) cells and plays important roles in the development of inflammatory diseases. Although IL-17F is highly homologous to IL-17A and binds the same receptor, the functional roles of this molecule remain largely unknown. Here, we demonstrated with Il17a(-/-), Il17f(-/-), and Il17a(-/-)Il17f(-/-) mice that IL-17F played only marginal roles, if at all, in the development of delayed-type and contact hypersensitivities, autoimmune encephalomyelitis, collagen-induced arthritis, and arthritis in Il1rn(-/-) mice. In contrast, both IL-17F and IL-17A were involved in host defense against mucoepithelial infection by Staphylococcus aureus and Citrobacter rodentium. IL-17A was produced mainly in T cells, whereas IL-17F was produced in T cells, innate immune cells, and epithelial cells. Although only IL-17A efficiently induced cytokines in macrophages, both cytokines activated epithelial innate immune responses. These observations indicate that IL-17A and IL-17F have overlapping yet distinct roles in host immune and defense mechanisms.
In vivo delivery of siRNA to immune cells by conjugation to a TLR9 agonist enhances antitumor immune responses.
Kortylewski Marcin,Swiderski Piotr,Herrmann Andreas,Wang Lin,Kowolik Claudia,Kujawski Maciej,Lee Heehyoung,Scuto Anna,Liu Yong,Yang Chunmei,Deng Jiehui,Soifer Harris S,Raubitschek Andrew,Forman Stephen,Rossi John J,Pardoll Drew M,Jove Richard,Yu Hua
Efficient delivery of small interfering (si)RNA to specific cell populations in vivo remains a formidable challenge to its successful therapeutic application. We show that siRNA synthetically linked to a CpG oligonucleotide agonist of toll-like receptor (TLR)9 targets and silences genes in TLR9(+) myeloid cells and B cells, both of which are key components of the tumor microenvironment. When a CpG-conjugated siRNA that targets the immune suppressor gene Stat3 is injected in mice either locally at the tumor site or intravenously, it enters tumor-associated dendritic cells, macrophages and B cells. Silencing of Stat3 leads to activation of tumor-associated immune cells and ultimately to potent antitumor immune responses. Our findings demonstrate the potential of TLR agonist-siRNA conjugates for targeted gene silencing coupled with TLR stimulation and immune activation in the tumor microenvironment.
Transcriptome analysis of functional differentiation between haploid and diploid cells of Emiliania huxleyi, a globally significant photosynthetic calcifying cell.
von Dassow Peter,Ogata Hiroyuki,Probert Ian,Wincker Patrick,Da Silva Corinne,Audic Stéphane,Claverie Jean-Michel,de Vargas Colomban
BACKGROUND:Eukaryotes are classified as either haplontic, diplontic, or haplo-diplontic, depending on which ploidy levels undergo mitotic cell division in the life cycle. Emiliania huxleyi is one of the most abundant phytoplankton species in the ocean, playing an important role in global carbon fluxes, and represents haptophytes, an enigmatic group of unicellular organisms that diverged early in eukaryotic evolution. This species is haplo-diplontic. Little is known about the haploid cells, but they have been hypothesized to allow persistence of the species between the yearly blooms of diploid cells. We sequenced over 38,000 expressed sequence tags from haploid and diploid E. huxleyi normalized cDNA libraries to identify genes involved in important processes specific to each life phase (2N calcification or 1N motility), and to better understand the haploid phase of this prominent haplo-diplontic organism. RESULTS:The haploid and diploid transcriptomes showed a dramatic differentiation, with approximately 20% greater transcriptome richness in diploid cells than in haploid cells and only <or= 50% of transcripts estimated to be common between the two phases. The major functional category of transcripts differentiating haploids included signal transduction and motility genes. Diploid-specific transcripts included Ca2+, H+, and HCO3- pumps. Potential factors differentiating the transcriptomes included haploid-specific Myb transcription factor homologs and an unusual diploid-specific histone H4 homolog. CONCLUSIONS:This study permitted the identification of genes likely involved in diploid-specific biomineralization, haploid-specific motility, and transcriptional control. Greater transcriptome richness in diploid cells suggests they may be more versatile for exploiting a diversity of rich environments whereas haploid cells are intrinsically more streamlined.
Proteolytic cleavage in an endolysosomal compartment is required for activation of Toll-like receptor 9.
Park Boyoun,Brinkmann Melanie M,Spooner Eric,Lee Clarissa C,Kim You-Me,Ploegh Hidde L
Toll-like receptors (TLRs) activate the innate immune system in response to pathogens. Here we show that TLR9 proteolytic cleavage is a prerequisite for TLR9 signaling. Inhibition of lysosomal proteolysis rendered TLR9 inactive. The carboxy-terminal fragment of TLR9 thus generated included a portion of the TLR9 ectodomain, as well as the transmembrane and cytoplasmic domains. This cleavage fragment bound to the TLR9 ligand CpG DNA and, when expressed in Tlr9(-/-) dendritic cells, restored CpG DNA-induced cytokine production. Although cathepsin L generated the requisite TLR9 cleavage products in a cell-free in vitro system, several proteases influenced TLR9 cleavage in intact cells. Lysosomal proteolysis thus contributes to innate immunity by facilitating specific cleavage of TLR9.
Tonic B cell antigen receptor signals supply an NF-kappaB substrate for prosurvival BLyS signaling.
Stadanlick Jason E,Kaileh Mary,Karnell Fredrick G,Scholz Jean L,Miller Juli P,Quinn William J,Brezski Randall J,Treml Laura S,Jordan Kimberly A,Monroe John G,Sen Ranjan,Cancro Michael P
The survival of transitional and mature B cells requires both the B cell antigen receptor (BCR) and BLyS receptor 3 (BR3), which suggests that these receptors send signals that are nonredundant or that engage in crosstalk with each other. Here we show that BCR signaling induced production of the nonclassical transcription factor NF-kappaB pathway substrate p100, which is required for transmission of BR3 signals and thus B cell survival. The capacity for sustained p100 production emerged during transitional B cell differentiation, the stage at which BCR signals begin to mediate survival rather than negative selection. Our findings identify a molecular mechanism for the reliance of primary B cells on continuous BR3 and BCR signaling, as well as for the gradual resistance to negative selection that is acquired during B cell maturation.
Nonredundant and complementary functions of TRAF2 and TRAF3 in a ubiquitination cascade that activates NIK-dependent alternative NF-kappaB signaling.
Vallabhapurapu Sivakumar,Matsuzawa Atsushi,Zhang Weizhou,Tseng Ping-Hui,Keats Jonathan J,Wang Haopeng,Vignali Dario A A,Bergsagel P Leif,Karin Michael
The adaptor and signaling proteins TRAF2, TRAF3, cIAP1 and cIAP2 may inhibit alternative nuclear factor-kappaB (NF-kappaB) signaling in resting cells by targeting NF-kappaB-inducing kinase (NIK) for ubiquitin-dependent degradation, thus preventing processing of the NF-kappaB2 precursor protein p100 to release p52. However, the respective functions of TRAF2 and TRAF3 in NIK degradation and activation of alternative NF-kappaB signaling have remained elusive. We now show that CD40 or BAFF receptor activation result in TRAF3 degradation in a cIAP1-cIAP2- and TRAF2-dependent way owing to enhanced cIAP1, cIAP2 TRAF3-directed ubiquitin ligase activity. Receptor-induced activation of cIAP1 and cIAP2 correlated with their K63-linked ubiquitination by TRAF2. Degradation of TRAF3 prevented association of NIK with the cIAP1-cIAP2-TRAF2 ubiquitin ligase complex, which resulted in NIK stabilization and NF-kappaB2-p100 processing. Constitutive activation of this pathway causes perinatal lethality and lymphoid defects.
Poor allostimulatory function of liver plasmacytoid DC is associated with pro-apoptotic activity, dependent on regulatory T cells.
Tokita Daisuke,Sumpter Tina L,Raimondi Giorgio,Zahorchak Alan F,Wang Zhiliang,Nakao Atsunori,Mazariegos George V,Abe Masanori,Thomson Angus W
Journal of hepatology
BACKGROUND/AIMS:The liver is comparatively rich in plasmacytoid (p) dendritic cells (DC), - innate immune effector cells that are also thought to play key roles in the induction and regulation of adaptive immunity. METHODS:Liver and spleen pDC were purified from fms-like tyrosine kinase ligand-treated control or lipopolysaccharide-injected C57BL/10 mice. Flow cytometric and molecular biologic assays were used to characterize their function and interaction with naturally occurring regulatory T cells (Treg). RESULTS:While IL-10 production was greater for freshly isolated liver compared with splenic pDC, the former produced less bioactive IL-12p70. Moreover, liver pDC expressed a low Delta4/Jagged1 Notch ligand ratio, skewed towards T helper 2 cell differentiation/cytokine production, and promoted allogeneic CD4(+)T cell apoptosis. T cell proliferation in response to liver pDC was, however, enhanced by blocking IL-10 function at the initiation of cultures. In the absence of naturally occurring CD4(+)CD25(+) regulatory T cells, similar levels of T cell proliferation were induced by liver and spleen pDC and the pro-apoptotic activity of liver pDC was reversed. CONCLUSIONS:The inferior T cell allostimulatory activity of in vivo-stimulated liver pDC may depend on the presence and function of Treg, a property that may contribute to inherent liver tolerogenicity.
Nedd4 augments the adaptive immune response by promoting ubiquitin-mediated degradation of Cbl-b in activated T cells.
Yang Baoli,Gay Denise L,MacLeod Megan K L,Cao Xiao,Hala Tamara,Sweezer Eileen M,Kappler John,Marrack Philippa,Oliver Paula M
Nedd4 and Itch are E3 ubiquitin ligases that ubiquitinate similar targets in vitro and thus are thought to function similarly. T cells lacking Itch show spontaneous activation and T helper type 2 polarization. To test whether loss of Nedd4 affects T cells in the same way, we generated Nedd4(+/+) and Nedd4(-/-) fetal liver chimeras. Nedd4(-/-) T cells developed normally but proliferated less, produced less interleukin 2 and provided inadequate help to B cells. Nedd4(-/-) T cells contained more of the E3 ubiquitin ligase Cbl-b, and Nedd4 was required for polyubiquitination of Cbl-b induced by CD28 costimulation. Our data demonstrate that Nedd4 promotes the conversion of naive T cells into activated T cells. We propose that Nedd4 and Itch ubiquitinate distinct target proteins in vivo.
Distinct functions for the transcription factor Foxo1 at various stages of B cell differentiation.
Dengler Hart S,Baracho Gisele V,Omori Sidne A,Bruckner Shane,Arden Karen C,Castrillon Diego H,DePinho Ronald A,Rickert Robert C
The transcription factors Foxo1, Foxo3 and Foxo4 modulate cell fate 'decisions' in diverse systems. Here we show that Foxo1-dependent gene expression was critical at many stages of B cell differentiation. Early deletion of Foxo1 caused a substantial block at the pro-B cell stage due to a failure to express interleukin 7 receptor-alpha. Foxo1 inactivation in late pro-B cells resulted in an arrest at the pre-B cell stage due to lower expression of the recombination-activating genes Rag1 and Rag2. Deletion of Foxo1 in peripheral B cells led to fewer lymph node B cells due to lower expression of L-selectin and failed class-switch recombination due to impaired upregulation of the gene encoding activation-induced cytidine deaminase. Thus, Foxo1 regulates a transcriptional program that is essential for early B cell development and peripheral B cell function.
Autophagy variation within a cell population determines cell fate through selective degradation of Fap-1.
Gump Jacob M,Staskiewicz Leah,Morgan Michael J,Bamberg Alison,Riches David W H,Thorburn Andrew
Nature cell biology
Autophagy regulates cell death both positively and negatively, but the molecular basis for this paradox remains inadequately characterized. We demonstrate here that transient cell-to-cell variations in autophagy can promote either cell death or survival depending on the stimulus and cell type. By separating cells with high and low basal autophagy using flow cytometry, we demonstrate that autophagy determines which cells live or die in response to death receptor activation. We have determined that selective autophagic degradation of the phosphatase Fap-1 promotes Fas apoptosis in Type I cells, which do not require mitochondrial permeabilization for efficient apoptosis. Conversely, autophagy inhibits apoptosis in Type II cells (which require mitochondrial involvement) or on treatment with TRAIL in either Type I or II cells. These data illustrate that differences in autophagy in a cell population determine cell fate in a stimulus- and cell-type-specific manner. This example of selective autophagy of an apoptosis regulator may represent a general mechanism for context-specific regulation of cell fate by autophagy.
Dual roles for hepatic lectin receptors in the clearance of chilled platelets.
Rumjantseva Viktoria,Grewal Prabhjit K,Wandall Hans H,Josefsson Emma C,Sørensen Anne Louise,Larson Göran,Marth Jamey D,Hartwig John H,Hoffmeister Karin M
Rapid chilling causes glycoprotein-Ib (GPIb) receptors to cluster on blood platelets. Hepatic macrophage beta(2) integrin binding to beta-N-acetylglucosamine (beta-GlcNAc) residues in the clusters leads to rapid clearance of acutely chilled platelets after transfusion. Although capping the beta-GlcNAc moieties by galactosylation prevents clearance of short-term-cooled platelets, this strategy is ineffective after prolonged refrigeration. We report here that prolonged refrigeration increased the density and concentration of exposed galactose residues on platelets such that hepatocytes, through Ashwell-Morell receptor binding, become increasingly involved in platelet removal. Macrophages rapidly removed a large fraction of transfused platelets independent of their storage conditions. With prolonged platelet chilling, hepatocyte-dependent clearance further diminishes platelet recovery and survival after transfusion. Inhibition of chilled platelet clearance by both beta(2) integrin and Ashwell-Morell receptors may afford a potentially simple method for storing platelets in the cold.
Extracellular histones are major mediators of death in sepsis.
Xu Jun,Zhang Xiaomei,Pelayo Rosana,Monestier Marc,Ammollo Concetta T,Semeraro Fabrizio,Taylor Fletcher B,Esmon Naomi L,Lupu Florea,Esmon Charles T
Hyperinflammatory responses can lead to a variety of diseases, including sepsis. We now report that extracellular histones released in response to inflammatory challenge contribute to endothelial dysfunction, organ failure and death during sepsis. They can be targeted pharmacologically by antibody to histone or by activated protein C (APC). Antibody to histone reduced the mortality of mice in lipopolysaccharide (LPS), tumor necrosis factor (TNF) or cecal ligation and puncture models of sepsis. Extracellular histones are cytotoxic toward endothelium in vitro and are lethal in mice. In vivo, histone administration resulted in neutrophil margination, vacuolated endothelium, intra-alveolar hemorrhage and macro- and microvascular thrombosis. We detected histone in the circulation of baboons challenged with Escherichia coli, and the increase in histone levels was accompanied by the onset of renal dysfunction. APC cleaves histones and reduces their cytotoxicity. Co-infusion of APC with E. coli in baboons or histones in mice prevented lethality. Blockade of protein C activation exacerbated sublethal LPS challenge into lethality, which was reversed by treatment with antibody to histone. We conclude that extracellular histones are potential molecular targets for therapeutics for sepsis and other inflammatory diseases.
In childhood acute lymphoblastic leukemia, blasts at different stages of immunophenotypic maturation have stem cell properties.
le Viseur Christoph,Hotfilder Marc,Bomken Simon,Wilson Kerrie,Röttgers Silja,Schrauder André,Rosemann Annegret,Irving Julie,Stam Ronald W,Shultz Leonard D,Harbott Jochen,Jürgens Heribert,Schrappe Martin,Pieters Rob,Vormoor Josef
We examined the leukemic stem cell potential of blasts at different stages of maturation in childhood acute lymphoblastic leukemia (ALL). Human leukemic bone marrow was transplanted intrafemorally into NOD/scid mice. Cells sorted using the B precursor differentiation markers CD19, CD20, and CD34 were isolated from patient samples and engrafted mice before serial transplantation into primary or subsequent (up to quaternary) recipients. Surprisingly, blasts representative of all of the different maturational stages were able to reconstitute and reestablish the complete leukemic phenotype in vivo. Sorted blast populations mirrored normal B precursor cells with transcription of a number of stage-appropriate genes. These observations inform a model for leukemia-propagating stem cells in childhood ALL.
Hyperglycemia-induced platelet activation in type 2 diabetes is resistant to aspirin but not to a nitric oxide-donating agent.
Gresele Paolo,Marzotti Stefania,Guglielmini Giuseppe,Momi Stefania,Giannini Silvia,Minuz Pietro,Lucidi Paola,Bolli Geremia B
OBJECTIVE:Acute, short-term hyperglycemia enhances high shear stress-induced platelet activation in type 2 diabetes. Several observations suggest that platelets in type 2 diabetes are resistant to inhibition by aspirin. Our aim was to assess comparatively the effect of aspirin, a nitric oxide-donating agent (NCX 4016), their combination, or placebo on platelet activation induced by acute hyperglycemia in type 2 diabetes. RESEARCH DESIGN AND METHODS:In a double-blind, placebo-controlled, randomized trial, 40 type 2 diabetic patients were allocated to 100 mg aspirin once daily, 800 mg NCX 4016 b.i.d., both of them, or placebo for 15 days. On day 15, 1 h after the morning dose, a 4-h hyperglycemic clamp (plasma glucose 13.9 mmol/l) was performed, and blood samples were collected before and immediately after it for platelet activation and cyclooxygenase-1 (COX-1) inhibition studies. RESULTS Acute hyperglycemia enhanced shear stress-induced platelet activation in placebo-treated patients (basal closure time 63 +/- 7.1 s, after hyperglycemia 49.5 +/- 1.4 s, -13.5 +/- 6.3 s, P < 0.048). Pretreatment with aspirin, despite full inhibition of platelet COX-1, did not prevent it (-12.7 +/- 6.9 s, NS vs. placebo). On the contrary, pretreatment with the NO donor NCX 4016, alone or in combination with aspirin, suppressed platelet activation induced by acute hyperglycemia (NCX 4016 +10.5 +/- 8.3 s; NCX 4016 plus aspirin: +12.0 +/- 10.7 s, P < 0.05 vs. placebo for both). Other parameters of shear stress-dependent platelet activation were also more inhibited by NCX 4016 than by aspirin, despite lesser inhibition of COX-1. CONCLUSIONS:Acute hyperglycemia-induced enhancement of platelet activation is resistant to aspirin; a NO-donating agent suppresses it. Therapeutic approaches aiming at a wider platelet inhibitory action than that exerted by aspirin may prove useful in patients with type 2 diabetes.
Small Molecule T315 Promotes Casitas B-Lineage Lymphoma-Dependent Degradation of Epidermal Growth Factor Receptor via Y1045 Autophosphorylation.
Huang Kuo-Yen,Kao Shih-Han,Wang Wen-Lung,Chen Chi-Yuan,Hsiao Tzu-Hung,Salunke Santosh B,Chen Jeremy J W,Su Kang-Yi,Yang Shuenn-Chen,Hong Tse-Ming,Chen Ching-Shih,Yang Pan-Chyr
American journal of respiratory and critical care medicine
RATIONALE:Despite the fact that tyrosine kinase inhibitors (TKIs) have been found effective in treating patients harboring activating mutations of epidermal growth factor receptor (EGFR), an acquired secondary mutation, T790M, which lowers the affinity to TKIs, can lead to EGFR TKI resistance after this standard treatment. OBJECTIVES:To evaluate the effect of small molecule T315 on EGFR degradation and its therapeutic efficacy in vitro and in vivo. METHODS:Lung adenocarcinoma cells were treated with T315, and cell proliferation and apoptotic proportion were determined by the CellTiter 96 AQueous MTS (3-[4,5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H-tetrazolium, inner salt) assay and flow cytometry. The effects of T315 on EGFR mRNA and protein levels, autophosphorylation, ubiquitination, and degradation were evaluated by real-time polymerase chain reaction and Western blot, respectively. Direct targeting of T315 to EGFR was confirmed by the in vitro kinase assay and mass spectrometry. Finally, the preclinical effect of T315 was validated in the murine xenograft model in combination with a second-generation TKI, afatinib. MEASUREMENTS AND MAIN RESULTS:We identified T315 as a novel, potent small molecule for suppressing cancer cell proliferation in vitro and in vivo. The therapeutic effect was verified after T315 was combined with a second-generation TKI, afatinib, compared with a single drug administration. We found a new mechanism of action, in that T315 appears to directly bind EGFR and triggers EGFR-Y1045 autophosphorylation, whereby its degradation is triggered through the ubiquitin-proteasome pathway. CONCLUSIONS:Our evidence suggests that T315 is a novel class of anticancer drug that is able to inhibit the growth of EGFR-TKI-resistant lung adenocarcinoma cells by inducing the degradation of EGFR.
Gut-Specific Delivery of T-Helper 17 Cells Reduces Obesity and Insulin Resistance in Mice.
Hong Chun-Pyo,Park Areum,Yang Bo-Gie,Yun Chang Ho,Kwak Min-Jung,Lee Gil-Woo,Kim Jung-Hwan,Jang Min Seong,Lee Eun-Jung,Jeun Eun-Ji,You Gihoon,Kim Kwang Soon,Choi Youngwoo,Park Ji-Hwan,Hwang Daehee,Im Sin-Hyeog,Kim Jihyun F,Kim Yoon-Keun,Seoh Ju-Young,Surh Charles D,Kim You-Me,Jang Myoung Ho
BACKGROUND & AIMS:Obesity and metabolic syndrome have been associated with alterations to the intestinal microbiota. However, few studies examined the effects of obesity on the intestinal immune system. We investigated changes in subsets of intestinal CD4 T-helper (T) cells with obesity and the effects of gut-tropic T17 cells in mice on a high-fat diet (HFD). METHODS:We isolated immune cells from small intestine and adipose tissue of C57BL/6 mice fed a normal chow diet or a HFD for 10 weeks and analyzed the cells by flow cytometry. Mice fed a vitamin A-deficient HFD were compared with mice fed a vitamin A-sufficient HFD. Obese RAG1-deficient mice were given injections of only regulatory T cells or a combination of regulatory T cells and T17 cells (wild type or deficient in integrin β7 subunit or interleukin 17 [IL17]). Mice were examined for weight gain, fat mass, fatty liver, glucose tolerance, and insulin resistance. Fecal samples were collected before and after T cell transfer and analyzed for microbiota composition by metagenomic DNA sequencing and quantitative polymerase chain reaction. RESULTS:Mice placed on a HFD became obese, which affected the distribution of small intestinal CD4 T cells. Intestinal tissues from obese mice had significant reductions in the proportion of T17 cells but increased proportion of T1 cells, compared with intestinal tissues from nonobese mice. Depletion of vitamin A in obese mice further reduced the proportion of T17 cells in small intestine; this reduction correlated with more weight gain and worsening of glucose intolerance and insulin resistance. Adoptive transfer of in vitro-differentiated gut-tropic T17 cells to obese mice reduced these metabolic defects, which required the integrin β7 subunit and IL17. Delivery of T17 cells to intestines of mice led to expansion of commensal microbes associated with leanness. CONCLUSIONS:In mice, intestinal T17 cells contribute to development of a microbiota that maintains metabolic homeostasis, via IL17. Gut-homing T17 cells might be used to reduce metabolic disorders in obese individuals.
Direct-Acting Antiviral Therapy Restores Immune Tolerance to Patients With Hepatitis C Virus-Induced Cryoglobulinemia Vasculitis.
Comarmond Cloé,Garrido Marlène,Pol Stanislas,Desbois Anne-Claire,Costopoulos Myrto,Le Garff-Tavernier Magali,Si Ahmed Si Nafa,Alric Laurent,Fontaine Hélène,Bellier Bertrand,Maciejewski Anna,Rosenzwajg Michelle,Klatzmann David,Musset Lucile,Poynard Thierry,Cacoub Patrice,Saadoun David
BACKGROUND & AIMS:Interferon-free direct-acting antiviral (DAA) therapies are effective in patients with hepatitis C virus-induced cryoglobulinemia vasculitis (HCV-CV). We analyzed blood samples from patients with HCV-CV before and after DAA therapy to determine mechanisms of these drugs and their effects on cellular immunity. METHODS:We performed a prospective study of 27 consecutive patients with HCV-CV (median age, 59 y) treated with DAA therapy (21 patients received sofosbuvir plus ribavirin for 24 weeks, 4 patients received sofosbuvir plus daclatasvir for 12 weeks, and 2 patients received sofosbuvir plus simeprevir for 12 weeks) in Paris, France. Blood samples were collected from these patients before and after DAA therapy, and also from 12 healthy donors and 12 individuals with HCV infection without CV. HCV load, cryoglobulins, and cytokines were quantified by flow cytometry, cytokine multiplex assays, and enzyme-linked immunosorbent assay. RESULTS:Twenty-four patients (88.9%) had a complete clinical response of CV to DAA therapy at week 24, defined by improvement of all the affected organs and the absence of relapse. Compared with healthy donors and patients with HCV infection without CV, patients with HCV-CV, before DAA therapy, had a lower percentage of CD4+CD25hiFoxP3+ regulatory T cells (P < .01), but higher proportions of IgM+CD21-/low memory B cells (P < .05), CD4+IFNγ+ cells (P < .01), CD4+IL17A+ cells (P < .01), and CD4+CXCR5+interleukin 21+ follicular T-helper (Tfh) cells (P < .01). In patients with HCV-CV, there was a negative correlation between numbers of IgM+CD21-/low memory B cells and T-regulatory cells (P = .03), and positive correlations with numbers of Tfh cells (P = .03) and serum levels of cryoglobulin (P = .01). DAA therapy increased patients' numbers of T-regulatory cells (1.5% ± 0.18% before therapy vs 2.1% ± 0.18% after therapy), decreased percentages of IgM+CD21-/low memory B cells (35.7% ± 6.1% before therapy vs 14.9% ± 3.8% after therapy), and decreased numbers of Tfh cells (12% ± 1.3% before therapy vs 8% ± 0.9% after therapy). Expression levels of B lymphocyte stimulator receptor 3 and programmed cell death 1 on B cells increased in patients with HCV-CV after DAA-based therapy (mean fluorescence units, 37 ± 2.4 before therapy vs 47 ± 2.6 after therapy, P < .01; and 29 ± 7.3 before therapy vs 48 ± 9.3 after therapy, P < .05, respectively). CONCLUSIONS:In a prospective clinical trial of patients with HCV-CV, DAA-based therapy restored disturbances in peripheral B- and T-cell homeostasis.
Salmonella disrupts lymph node architecture by TLR4-mediated suppression of homeostatic chemokines.
St John Ashley L,Abraham Soman N
We report that infection of draining lymph nodes (DLNs) by Salmonella typhimurium results in the specific downregulation of the homeostatic chemokines CCL21 and CXCL13, which are essential for normal DLN organization and function. Our data reveal that the mechanism of this suppression is dependent on S. typhimurium LPS (sLPS). The decrease in CCL21 expression involves interaction between sLPS and CCL21-producing cells within DLNs, triggering a distinct Toll-like receptor 4 (TLR4)-mediated host signaling response. In this response, suppressor of cytokine signaling-3 (Socs3) is upregulated, which negatively regulates mothers against decapentaplegic homolog-3 (Smad3)-initiated production of CCL21. Disruption of lymph node architecture and cellular trafficking enhances S. typhimurium virulence and could represent a mechanism of immune suppression used by pathogens that primarily target lymphoid tissue.
A novel screening system improves genetic correction by internal exon replacement.
Koller Ulrich,Wally Verena,Mitchell Lloyd G,Klausegger Alfred,Murauer Eva M,Mayr Elisabeth,Gruber Christina,Hainzl Stefan,Hintner Helmut,Bauer Johann W
Nucleic acids research
Trans-splicing is a powerful approach to reprogram the genome. It can be used to replace 5', 3' or internal exons. The latter approach has been characterized by low efficiency, as the requirements to promote internal trans-splicing are largely uncharacterized. The trans-splicing process is induced by engineered 'RNA trans-splicing molecules' (RTMs), which target a selected pre-mRNA to be reprogrammed via two complementary binding domains. To facilitate the development of more efficient RTMs for therapeutic applications we constructed a novel fluorescence based screening system. We incorporated exon 52 of the COL17A1 gene into a GFP-based cassette system as the target exon. This exon is mutated in many patients with the devastating skin blistering disease epidermolysis bullosa. In a double transfection assay we were able to rapidly identify optimal binding domains targeted to sequences in the surrounding introns 51 and 52. The ability to replace exon 52 was then evaluated in a more endogenous context using a target containing COL17A1 exon 51-intron 51-exon 52-intron 52-exon 53. Two selected RTMs produced significantly higher levels of GFP expression in up to 61% assayed cells. This novel approach allows for rapid identification of efficient RTMs for internal exon replacement.
Shape-dependent cellular processing of polyelectrolyte capsules.
Shimoni Olga,Yan Yan,Wang Yajun,Caruso Frank
Particle shape is emerging as a key design parameter for tailoring the interactions between particles and cells. Herein, we report the preparation of rod-shaped layer-by-layer (LbL)-assembled polymer hydrogel capsules with tunable aspect ratios (ARs). By templating spherical and rodlike silica particles, disulfide-stabilized poly(methacrylic acid) hydrogel capsules (PMA HCs) with different ARs (from 1 to 4) are generated. The influence of capsule AR on cellular internalization and intracellular fate was quantitatively investigated by flow cytometry, imaging flow cytometry, and fluorescence deconvolution microscopy. These experiments reveal that the cellular internalization kinetics of PMA HCs are dependent on the AR, with spherical capsules being internalized more rapidly and to a greater extent compared with rod-shaped capsules. In contrast, the capsules with different ARs are colocalized with the lysosomal marker LAMP1, suggesting that the lysosomal compartmentalization is independent of shape for these soft polymer capsules.
miR-124 regulates adult neurogenesis in the subventricular zone stem cell niche.
Cheng Li-Chun,Pastrana Erika,Tavazoie Masoud,Doetsch Fiona
The subventricular zone (SVZ) is the largest neurogenic niche in the adult mammalian brain. We found that the brain-enriched microRNA miR-124 is an important regulator of the temporal progression of adult neurogenesis in mice. Knockdown of endogenous miR-124 maintained purified SVZ stem cells as dividing precursors, whereas ectopic expression led to precocious and increased neuron formation. Furthermore, blocking miR-124 function during regeneration led to hyperplasias, followed by a delayed burst of neurogenesis. We identified the SRY-box transcription factor Sox9 as being a physiological target of miR-124 at the transition from the transit amplifying cell to the neuroblast stage. Sox9 overexpression abolished neuronal differentiation, whereas Sox9 knockdown led to increased neuron formation. Thus miR-124-mediated repression of Sox9 is important for progression along the SVZ stem cell lineage to neurons.
Single cell transcriptional profiling reveals heterogeneity of human induced pluripotent stem cells.
Narsinh Kazim H,Sun Ning,Sanchez-Freire Veronica,Lee Andrew S,Almeida Patricia,Hu Shijun,Jan Taha,Wilson Kitchener D,Leong Denise,Rosenberg Jarrett,Yao Mylene,Robbins Robert C,Wu Joseph C
The Journal of clinical investigation
Human induced pluripotent stem cells (hiPSCs) and human embryonic stem cells (hESCs) are promising candidate cell sources for regenerative medicine. However, despite the common ability of hiPSCs and hESCs to differentiate into all 3 germ layers, their functional equivalence at the single cell level remains to be demonstrated. Moreover, single cell heterogeneity amongst stem cell populations may underlie important cell fate decisions. Here, we used single cell analysis to resolve the gene expression profiles of 362 hiPSCs and hESCs for an array of 42 genes that characterize the pluripotent and differentiated states. Comparison between single hESCs and single hiPSCs revealed markedly more heterogeneity in gene expression levels in the hiPSCs, suggesting that hiPSCs occupy an alternate, less stable pluripotent state. hiPSCs also displayed slower growth kinetics and impaired directed differentiation as compared with hESCs. Our results suggest that caution should be exercised before assuming that hiPSCs occupy a pluripotent state equivalent to that of hESCs, particularly when producing differentiated cells for regenerative medicine aims.
Live cell imaging distinguishes bona fide human iPS cells from partially reprogrammed cells.
Chan Elayne M,Ratanasirintrawoot Sutheera,Park In-Hyun,Manos Philip D,Loh Yuin-Han,Huo Hongguang,Miller Justine D,Hartung Odelya,Rho Junsung,Ince Tan A,Daley George Q,Schlaeger Thorsten M
Somatic cells can be reprogrammed into induced pluripotent stem (iPS) cells by enforced expression of transcription factors. Using serial live imaging of human fibroblasts undergoing reprogramming, we identified distinct colony types that morphologically resemble embryonic stem (ES) cells yet differ in molecular phenotype and differentiation potential. By analyzing expression of pluripotency markers, methylation at the OCT4 and NANOG promoters and differentiation into teratomas, we determined that only one colony type represents true iPS cells, whereas the others represent reprogramming intermediates. Proviral silencing and expression of TRA-1-60, DNMT3B and REX1 can be used to distinguish the fully reprogrammed state, whereas alkaline phosphatase, SSEA-4, GDF3, hTERT and NANOG are insufficient as markers. We also show that reprogramming using chemically defined medium favors formation of fully reprogrammed over partially reprogrammed colonies. Our data define molecular markers of the fully reprogrammed state and highlight the need for rigorous characterization and standardization of putative iPS cells.
Ceramide-CD300f binding suppresses experimental colitis by inhibiting ATP-mediated mast cell activation.
Matsukawa Toshihiro,Izawa Kumi,Isobe Masamichi,Takahashi Mariko,Maehara Akie,Yamanishi Yoshinori,Kaitani Ayako,Okumura Ko,Teshima Takanori,Kitamura Toshio,Kitaura Jiro
OBJECTIVE:Extracellular ATP mediates mast cell-dependent intestinal inflammation via P2X7 purinoceptors. We have previously shown that CD300f (also called the leucocyte mono-immunoglobulin-like receptor 3 (LMIR3)) suppresses immunoglobulin E-dependent and mast cell-dependent allergic responses by binding to ceramide. The aim of the present study was to clarify the role of ceramide-LMIR3 interaction in the development of IBD. DESIGN:The dextran sodium sulfate (DSS)-induced colitis model was used in wild-type (WT), LMIR3(-/-), mast cell-deficient Kit(W-sh/W-sh), Kit(W-sh/W-sh)LMIR3(-/-) or Kit(W-sh/W-sh) mice engrafted with WT or LMIR3(-/-) bone marrow-derived mast cells (BMMCs). The severity of colitis was determined by clinical and histological criteria. Lamina propria cell populations were assessed by flow cytometry. Production of chemical mediators from lamina propria cells was measured by real-time reverse transcription PCR. Production of chemical mediators from ATP-stimulated BMMCs in the presence or absence of ceramide was measured by ELISA. The severity of DSS-induced colitis was assessed in mice given either an Fc fusion protein containing an extracellular domain of LMIR3, and anticeramide antibody, or ceramide liposomes. RESULTS:LMIR3 deficiency exacerbated DSS-induced colitis in mice. Kit(W-sh/W-sh) mice harbouring LMIR3(-/-) mast cells exhibited more severe colitis than those harbouring WT mast cells. Ceramide-LMIR3 interaction inhibited ATP-stimulated activation of BMMCs. DSS-induced colitis was aggravated by disrupting the ceramide-LMIR3 interaction, whereas it was suppressed by treating with ceramide liposomes. CONCLUSIONS:LMIR3-deficient colonic mast cells were pivotal in the exacerbation of DSS-induced colitis in LMIR3(-/-) mice. Ceramide liposomes attenuated DSS-induced colitis by inhibiting ATP-mediated activation of colonic mast cells through ceraimide-LMIR3 binding.
Involvement of X-box binding protein 1 and reactive oxygen species pathways in the pathogenesis of tumour necrosis factor receptor-associated periodic syndrome.
Dickie Laura J,Aziz Azad M,Savic Sinisa,Lucherini Orso M,Cantarini Luca,Geiler Janina,Wong Chi H,Coughlan Robert,Lane Thirusha,Lachmann Helen J,Hawkins Philip N,Robinson Philip A,Emery Paul,McGonagle Dennis,McDermott Michael F
Annals of the rheumatic diseases
OBJECTIVES:To investigate convergence of endoplasmic reticulum stress pathways and enhanced reactive oxygen species (ROS) production, due to intracellular retention of mutant tumour necrosis factor receptor 1 (TNFR1), as a disease mechanism in TNFR-associated periodic syndrome (TRAPS). METHODS:Peripheral blood mononuclear cells from patients with TRAPS (n=16) and healthy controls (HC) (n=22) were studied alongside HEK293T cells expressing wild type-TNFR1 or TRAPS-associated mutations. Unfolded protein response (UPR)-associated proteins (protein kinase-like endoplasmic reticulum kinase, PERK), phosphorylated-PERK (p-PERK), phosphorylated inositol-requiring enzyme 1α (p-IRE1α) and spliced X-box binding protein 1 (sXBP1)) were measured by flow cytometry. XBP1 splicing and UPR-associated transcript expression were assessed by reverse transcription PCR/quantitative real-time PCR. ROS levels were measured using CM-H(2)DCFDA and MitoSOX Red in patients' monocytes or HEK293T cells by flow cytometry. RESULTS:Mutant TNFR1-expressing HEK293T cells had increased TNFR1 expression associated with intracellular aggregation. TRAPS patients had increased sXBP1 transcripts (p<0.01) compared with HC. Raised p-PERK protein was seen, indicative of an UPR, but other UPR-associated transcripts were normal. Increased ROS levels were observed in TRAPS monocytes compared with HCs (p<0.02); these increased further upon IL-6 stimulation (p<0.01). Lipopolysaccharide-stimulated peripheral blood mononuclear cells of patients with TRAPS, but not HCs, demonstrated increased sXBP1 levels (p<0.01), which were reduced by antioxidant treatment (p<0.05). CONCLUSIONS:Patients with TRAPS have evidence of increased sXBP1 and PERK expression but without other signs of classical UPR, and also with high ROS generation that may contribute to the pro-inflammatory state associated with TRAPS. The authors propose a non-traditional XBP1 pathway with enhanced sXBP1 as a novel disease-contributing mechanism in TRAPS.
The metalloprotease-disintegrin ADAM8 is essential for the development of experimental asthma.
Naus Silvia,Blanchet Marie-Renée,Gossens Klaus,Zaph Colby,Bartsch Jörg W,McNagny Kelly M,Ziltener Hermann J
American journal of respiratory and critical care medicine
RATIONALE:Expression of the metalloprotease ADAM8 is increased in patients with asthma, but the functional significance of elevated ADAM8 expression in the context of asthma pathogenesis remains elusive. OBJECTIVES:To study development of asthma in ADAM8-deficient mice. METHODS:Ovalbumin-induced asthma was studied in wild-type, ADAM8-deficient, and ADAM8-chimeric mice. Lung inflammation was assessed by histology, analysis of bronchoalveolar lavage, and airway hyperresponsiveness. MEASUREMENTS AND MAIN RESULTS:ADAM8-deficient mice are highly resistant to the development of ovalbumin-induced airway inflammation and hyperresponsiveness. ADAM8 expression was induced in both hematopoietic cells and the nonhematopoietic microenvironment after induction of asthma, and ADAM8 expression in both cell populations was required for the full manifestation of asthma. Interestingly, loss of ADAM8 on T cells alone was sufficient to significantly decrease the asthma response. The attenuated response was not due to an intrinsic defect in antigen presentation or cytokine production but reflected an impaired migration of T cells, eosinophils, CD11b(+) CD11c(-), and CD11c(+) cells from blood vessels to the lung and alveolar space, suggesting a general hematopoietic cell deficiency in the absence of ADAM8. CONCLUSIONS:The results show that ADAM8 plays a proinflammatory role in airway inflammation. The milder disease outcome in the absence of ADAM8 suggests that this protein might be an interesting new target in treatment of this, and potentially other, inflammatory diseases in which recruitment of inflammatory cells is an essential part of pathogenesis.
Fas/Fas ligand-mediated apoptosis promotes hypersensitivity pneumonitis in mice by enhancing maturation of dendritic cells.
Hwang Su Jin,Kim Hye Sung,Chung Doo Hyun
American journal of respiratory and critical care medicine
RATIONALE:Fas/Fas ligand (FasL)-mediated apoptosis has been implicated in various lung diseases, but whether Fas/FasL-mediated apoptosis in the lungs plays a critical role in the development of hypersensitivity pneumonitis (HP) is unclear. OBJECTIVES:To explore the functional roles of Fas/FasL-mediated apoptosis in HP. METHODS:Fas-deficient (lpr/lpr), FasL-deficient (gld/gld), and B6 mice were challenged with Saccharopolyspora rectivirgula (SR) antigen intranasally. MEASUREMENTS AND MAIN RESULTS:lpr/lpr and gld/gld mice exhibited attenuation of HP in terms of histological alterations, influx of immune cells in bronchoalveolar lavage fluid (BALF), and SR-specific immune responses compared with B6 mice, similar to the effects of SR in B6 mice given a caspase inhibitor. The lungs of lpr/lpr and gld/gld mice showed high IL-4 production and low IFN-gamma, IL-8, macrophage inflammatory protein-2, IL-1beta, and tumor necrosis factor-alpha production compared with those of B6 mice. Moreover, mice with chimeric B6 and lpr/lpr bone marrow revealed that apoptosis of nonhematopoietic and BALF immune cells of the lungs enhanced immune responses against SR antigen. Gr-1(+) granulocytes in BALF expressed annexin V and their depletion in B6 mice attenuated HP. Apoptosis of nonhematopoietic cells and Gr-1(+) granulocytes in the lungs enhanced the maturation of pulmonary CD11c(+) dendritic cells and their production of macrophage inflammatory protein-1alpha and monocyte chemoattractant protein-1, resulting in recruitment of immune cells into the lungs during HP. CONCLUSIONS:These results suggest that apoptosis in nonhematopoietic cells and Gr-1(+) granulocytes of the lungs promotes HP by enhancing maturation and chemokine production of CD11c(+) dendritic cells.
The G-protein-coupled receptor GPR40 directly mediates long-chain fatty acid-induced secretion of cholecystokinin.
Liou Alice P,Lu Xinping,Sei Yoshitatsu,Zhao Xilin,Pechhold Susanne,Carrero Ricardo J,Raybould Helen E,Wank Stephen
BACKGROUND & AIMS:Long-chain fatty acid receptors G-protein-coupled receptor 40 (GPR40) (FFAR1) and GPR120 have been implicated in the chemosensation of dietary fats. I cells in the intestine secrete cholecystokinin (CCK), a peptide hormone that stimulates digestion of fat and protein, but these cells are rare and hard to identify. We sought to determine whether dietary fat-induced secretion of CCK is directly mediated by GPR40 expressed on I cells. METHODS:We used fluorescence-activated cell sorting to isolate a pure population of I cells from duodenal mucosa in transgenic mice that expressed green fluorescent protein under the control of the CCK promoter (CCK-enhanced green fluorescent protein [eGFP] bacterial artificial chromosome mice). CCK-eGFP cells were evaluated for GPR40 expression by quantitative reverse transcription polymerase chain reaction and immunostaining. GPR40(-/-) mice were bred with CCK-eGFP mice to evaluate functional relevance of GPR40 on long-chain fatty acid-stimulated increases in [Ca(2+)]i and CCK secretion in isolated CCK-eGFP cells. Plasma levels of CCK after olive oil gavage were compared between GPR40(+/+) and GPR40(-/-) mice. RESULTS:Cells that expressed eGFP also expressed GPR40; expression of GPR40 was 100-fold greater than that of cells that did not express eGFP. In vitro, linoleic, oleic, and linolenic acids increased [Ca(2+)]i; linolenic acid increased CCK secretion by 53% in isolated GPR40(+/+) cells that expressed eGFP. In contrast, in GPR40(-/-) that expressed eGFP, [Ca(2+)]i response to linoleic acid was reduced by 50% and there was no significant CCK secretion in response to linolenic acid. In mice, olive oil gavage significantly increased plasma levels of CCK compared with pregavage levels: 5.7-fold in GPR40(+/+) mice and 3.1-fold in GPR40(-/-) mice. CONCLUSIONS:Long-chain fatty acid receptor GPR40 induces secretion of CCK by I cells in response to dietary fat.
Activation of Transforming Growth Factor Beta 1 Signaling in Gastric Cancer-associated Fibroblasts Increases Their Motility, via Expression of Rhomboid 5 Homolog 2, and Ability to Induce Invasiveness of Gastric Cancer Cells.
Ishimoto Takatsugu,Miyake Keisuke,Nandi Tannistha,Yashiro Masakazu,Onishi Nobuyuki,Huang Kie Kyon,Lin Suling Joyce,Kalpana Ramnarayanan,Tay Su Ting,Suzuki Yuka,Cho Byoung Chul,Kuroda Daisuke,Arima Kota,Izumi Daisuke,Iwatsuki Masaaki,Baba Yoshifumi,Oki Eiji,Watanabe Masayuki,Saya Hideyuki,Hirakawa Kosei,Baba Hideo,Tan Patrick
BACKGROUND & AIMS:Fibroblasts that interact with cancer cells are called cancer-associated fibroblasts (CAFs), which promote progression of different tumor types. We investigated the characteristics and functions of CAFs in diffuse-type gastric cancers (DGCs) by analyzing features of their genome and gene expression patterns. METHODS:We isolated CAFs and adjacent non-cancer fibroblasts (NFs) from 110 gastric cancer (GC) tissues from patients who underwent gastrectomy in Japan from 2008 through 2016. Cells were identified using specific markers of various cell types by immunoblot and flow cytometry. We selected pairs of CAFs and NFs for whole-exome and RNA sequencing analyses, and compared expression of specific genes using quantitative reverse transcription PCR. Protein levels and phosphorylation were compared by immunoblot and immunofluorescence analyses. Rhomboid 5 homolog 2 (RHBDF2) was overexpressed from a transgene in fibroblasts or knocked down using small interfering RNAs. Motility and invasiveness of isolated fibroblasts and GC cell lines (AGS, KATOIII, MKN45, NUGC3, NUGC4, OCUM-2MD3 and OCUM-12 cell lines) were quantified by real-time imaging analyses. We analyzed 7 independent sets of DNA microarray data from patients with GC and associated expression levels of specific genes with patient survival times. Nude mice were given injections of OCUM-2MD3 in the stomach wall; tumors and metastases were collected and analyzed by immunohistochemistry. RESULTS:Many of the genes with increased expression in CAFs compared with NFs were associated with transforming growth factor beta 1 (TGFB1) activity. When CAFs were cultured in extracellular matrix, they became more motile than NFs; DGC cells incubated with CAFs were also more motile and invasive in vitro than DGC cells not incubated with CAFs. When injected into nude mice, CAF-incubated DGC cells invaded a greater number of lymphatic vessels than NF-incubated DGC cells. We identified RHBDF2 as a gene overexpressed in CAFs compared with NFs. Knockdown of RHBDF2 in CAFs reduced their elongation and motility in response to TGFB1, whereas overexpression of RHBDF2 in NFs increased their motility in extracellular matrix. RHBDF2 appeared to regulate oncogenic and non-canonical TGFB1 signaling. Knockdown of RHBDF2 in CAFs reduced cleavage of the TGFB receptor 1 (TGFBR1) by ADAM metallopeptidase domain 17 (ADAM17 or TACE) and reduced expression of genes that regulate motility. Incubation of NFs with in interleukin 1 alpha (IL1A), IL1B or tumor necrosis factor, secreted by DGCs, increased fibroblast expression of RHBDF2. Simultaneous high expression of these cytokines in GC samples was associated with shorter survival times of patients. CONCLUSIONS:In CAFs isolated from human DGCs, we observed increased expression of RHBDF2, which regulates TGFB1 signaling. Expression of RHBDF2 in fibroblasts is induced by inflammatory cytokines (such as IL1A, IL1B, and tumor necrosis factor) secreted by DGCs. RHBDF2 promotes cleavage of TGFBR1 by activating TACE and motility of CAFs in response to TGFB1. These highly motile CAFs induce DGCs to invade extracellular matrix and lymphatic vessels in nude mice.
Esophageal Adenocarcinoma Cells and Xenograft Tumors Exposed to Erb-b2 Receptor Tyrosine Kinase 2 and 3 Inhibitors Activate Transforming Growth Factor Beta Signaling, Which Induces Epithelial to Mesenchymal Transition.
Ebbing Eva A,Steins Anne,Fessler Evelyn,Stathi Phylicia,Lesterhuis Willem Joost,Krishnadath Kausilia K,Vermeulen Louis,Medema Jan Paul,Bijlsma Maarten F,van Laarhoven Hanneke W M
BACKGROUND & AIMS:Drugs that inhibit the erb-b2 receptor tyrosine kinase 2 (ERBB2 or HER2) are the standard treatment of patients with different types of cancer, including HER2-overexpressing gastroesophageal tumors. Unfortunately, cancer cells become resistant to these drugs, so overall these drugs provide little benefit to patients with these tumors. We investigated mechanisms that mediate resistance of esophageal adenocarcinoma (EAC) cells and patient-derived xenograft tumors to ERBB inhibitors. METHODS:We cultured primary tumor cells, isolated from EAC patient samples, and OE19 and OE33 EAC cell lines with trastuzumab (an inhibitor of HER2), with or without pertuzumab (which inhibits dimerization of HER2 with HER3) or a specific antibody against HER3 (anti-HER3). HER2 was knocked down by expression of small hairpin RNAs. In addition, cells were incubated with NRG1-β, a mediator of HER2-HER3 signaling, or A83-01, an inhibitor of transforming growth factor beta (TGFβ) signaling. Cells were analyzed for markers of the epithelial to mesenchymal transition (EMT) using flow cytometry, immunofluorescence, and quantitative reverse transcription polymerase chain reaction. We performed limiting dilution, transwell, and cell viability assays to study the functional effects of HER2 and HER3 inhibition and reactivation. We analyzed publicly available EAC gene expression datasets to correlate expression of ERBB genes with genes encoding epithelial and mesenchymal proteins. NOD.Cg-PrkdcIl2rg/SzJ (NSG) mice were given subcutaneous injections of AMC-EAC-007B cells and also given injections of single or combined inhibitors; growth of these patient-derived xenograft tumors was quantified. RESULTS:EAC cells incubated with trastuzumab decreased expression of epithelial markers (CD24, CD29, and CDH1) and increased expression of mesenchymal markers (CXCR4, VIM, ZEB1, SNAI2, and CDH2), compared with cells not exposed to trastuzumab, indicating induction of EMT. Addition of NRG1-β to these cells restored their epithelial phenotype. Incubation of EAC cells with trastuzumab and pertuzumab accelerated the expression of EMT markers, compared with cells incubated with trastuzumab alone. EAC cells cultured for 2 months with a combination of trastuzumab and pertuzumab became resistant to chemotherapeutic agents (5-fluoruracil, carboplatin, cisplatin, eribulin, and paclitaxel), based on their continued viability, which was accompanied with an enhanced migratory capacity in transwell assays and clonogenicity in limiting dilution analyses. In comparisons of EAC gene expression patterns, we associated high expression of ERBB3 with an epithelial gene expression signature; expression of TGFβ correlated with expression of EMT-related genes, and we found an inverse correlation between expression of TGFB1 and ERBB3. EAC cells incubated with ERBB inhibitors began to secrete ligands for the TGFβ receptor and underwent EMT. Incubation of EAC cells with trastuzumab, followed by 10 days of incubation with the TGFβ receptor inhibitor in the presence of trastuzumab, caused cells to regain an epithelial phenotype. EAC patient-derived xenograft tumors grew more slowly in mice given the combination of trastuzumab, pertuzumab, and the TGFβ inhibitor than in mice given single agents or a combination of trastuzumab and pertuzumab. Tumors exposed to trastuzumab and pertuzumab expressed EMT markers and were poorly differentiated, whereas tumors exposed to the combination of trastuzumab, pertuzumab, and the TGFβ inhibitor expressed epithelial markers and were more differentiated. CONCLUSIONS:EAC cells become resistant to trastuzumab and pertuzumab by activating TGFβ signaling, which induces EMT. Agents that block TGFβ signaling can increase the anti-tumor efficacies of trastuzumab and pertuzumab.
Efficacy and Safety of Sofosbuvir Plus Daclatasvir for Treatment of HCV-Associated Cryoglobulinemia Vasculitis.
Saadoun David,Pol Stanislas,Ferfar Yasmina,Alric Laurent,Hezode Christophe,Si Ahmed Si Nafa,de Saint Martin Luc,Comarmond Cloé,Bouyer Anne Sophie,Musset Lucile,Poynard Thierry,Resche Rigon Matthieu,Cacoub Patrice
Circulating mixed cryoglobulins are detected in 40%-60% of patients with hepatitis C virus (HCV) infection, and overt cryoglobulinemia vasculitis (CryoVas) develops in approximately 15% of patients. Remission of vasculitis has been associated with viral clearance, but few studies have reported the effectiveness of direct-acting antiviral drugs in these patients. We performed an open-label, prospective, multicenter study of the effectiveness and tolerance of an all-oral, interferon- and ribavirin-free regimen of sofosbuvir plus daclatasvir in patients with HCV-associated CryoVas. Forty-one consecutive patients with active HCV-associated CryoVas (median age, 56 y; 53.6% women) were recruited from hospitals in Paris, France, from 2014 through 2016. They received sofosbuvir (400 mg/day) plus daclatasvir (60 mg/day) for 12 weeks (n = 32) or 24 weeks (n = 9), and were evaluated every 4 weeks until week 24 and at week 36. Blood samples were analyzed for complete blood count, serum chemistry profile, level of alanine aminotransferase, rheumatoid factor activity, C4 fraction of complement, and cryoglobulin; peripheral blood mononuclear cells were isolated for flow cytometry analysis. Thirty-seven patients (90.2%) had a complete clinical response (defined by improvement of all the affected organs involved at baseline and no clinical relapse) after a median time of 12 weeks of therapy; all had a sustained virologic response (no detectable serum HCV RNA 12 weeks after the end of antiviral therapy). Patients' mean cryoglobulin level decreased from 0.56 ± 0.18 at baseline to 0.21 ± 0.14 g/L at week 36, and no cryoglobulin was detected in 50% of patients at this time point. After antiviral therapy, patients had increased numbers of T-regulatory cells, IgM+CD21-/low-memory B cells, CD4+CXCR5+ interleukin 21+ cells, and T-helper 17 cells, compared with before therapy. After a median follow-up period of 26 months (interquartile range, 20-30 mo), no patients had a serious adverse event or relapse of vasculitis.
Increased Expression of Cytotoxic T-Lymphocyte-Associated Protein 4 by T Cells, Induced by B7 in Sera, Reduces Adaptive Immunity in Patients With Acute Liver Failure.
Khamri Wafa,Abeles Robin D,Hou Tie Zheng,Anderson Amy E,El-Masry Ahmed,Triantafyllou Evangelos,Bernsmeier Christine,Larsen Fin S,Singanayagam Arjuna,Kudo Nobuaki,Possamai Lucia A,Lebosse Fanny,Auzinger Georg,Bernal William,Willars Christopher,Weston Christopher J,Lombardi Giovanna,Wendon Julia,Thursz Mark,Antoniades Charalambos G
BACKGROUND & AIMS:Patients with acute liver failure (ALF) have defects in innate immune responses to microbes (immune paresis) and are susceptible to sepsis. Cytotoxic T-lymphocyte-associated protein 4 (CTLA4), which interacts with the membrane receptor B7 (also called CD80 and CD86), is a negative regulator of T-cell activation. We collected T cells from patients with ALF and investigated whether inhibitory signals down-regulate adaptive immune responses in patients with ALF. METHODS:We collected peripheral blood mononuclear cells from patients with ALF and controls from September 2013 through September 2015 (45 patients with ALF, 20 patients with acute-on-chronic liver failure, 15 patients with cirrhosis with no evidence of acute decompensation, 20 patients with septic shock but no cirrhosis or liver disease, and 20 healthy individuals). Circulating CD4 T cells were isolated and analyzed by flow cytometry. CD4 T cells were incubated with antigen, or agonist to CD3 and dendritic cells, with or without antibody against CTLA4; T-cell proliferation and protein expression were quantified. We measured levels of soluble B7 molecules in supernatants of isolated primary hepatocytes, hepatic sinusoidal endothelial cells, and biliary epithelial cells from healthy or diseased liver tissues. We also measured levels of soluble B7 serum samples from patients and controls, and mice with acetaminophen-induced liver injury using enzyme-linked immunosorbent assays. RESULTS:Peripheral blood samples from patients with ALF had a higher proportion of CD4 CTLA4 T cells than controls; patients with infections had the highest proportions. CD4 T cells from patients with ALF had a reduced proliferative response to antigen or CD3 stimulation compared to cells from controls; incubation of CD4 T cells from patients with ALF with an antibody against CTLA4 increased their proliferative response to antigen and to CD3 stimulation, to the same levels as cells from controls. CD4 T cells from controls up-regulated expression of CTLA4 after 24-48 hours culture with sera from patients with ALF; these sera were found to have increased concentrations of soluble B7 compared to sera from controls. Necrotic human primary hepatocytes exposed to acetaminophen, but not hepatic sinusoidal endothelial cells and biliary epithelial cells from patients with ALF, secreted high levels of soluble B7. Sera from mice with acetaminophen-induced liver injury contained high levels of soluble B7 compared to sera from mice without liver injury. Plasma exchange reduced circulating levels of soluble B7 in patients with ALF and expression of CTLA4 on T cells. CONCLUSIONS:Peripheral CD4 T cells from patients with ALF have increased expression of CTLA4 compared to individuals without ALF; these cells have a reduced response to antigen and CD3 stimulation. We found sera of patients with ALF and from mice with liver injury to have high concentrations of soluble B7, which up-regulates CTLA4 expression by T cells and reduces their response to antigen. Plasma exchange reduces levels of B7 in sera from patients with ALF and might be used to restore antimicrobial responses to patients.
EGFR in Tumor-Associated Myeloid Cells Promotes Development of Colorectal Cancer in Mice and Associates With Outcomes of Patients.
Srivatsa Sriram,Paul Mariel C,Cardone Claudia,Holcmann Martin,Amberg Nicole,Pathria Paulina,Diamanti Michaela A,Linder Markus,Timelthaler Gerald,Dienes Hans P,Kenner Lukas,Wrba Fritz,Prager Gerald W,Rose-John Stefan,Eferl Robert,Liguori Giuseppina,Botti Gerardo,Martinelli Erika,Greten Florian R,Ciardiello Fortunato,Sibilia Maria
BACKGROUND & AIMS:Inhibitors of the epidermal growth factor receptor (EGFR) are the first-line therapy for patients with metastatic colorectal tumors without RAS mutations. However, EGFR inhibitors are ineffective in these patients, and tumor level of EGFR does not associate with response to therapy. We screened human colorectal tumors for EGFR-positive myeloid cells and investigated their association with patient outcome. We also performed studies in mice to evaluate how EGFR expression in tumor cells and myeloid cells contributes to development of colitis-associated cancer and Apc-dependent intestinal tumorigenesis. METHODS:We performed immunohistochemical and immunofluorescent analyses of 116 colorectal tumor biopsies to determine levels of EGFR in tumor and stroma; we also collected information on tumor stage and patient features and outcomes. We used the Mann-Whitney U and Kruskal-Wallis tests to correlate tumor levels of EGFR with tumor stage, and the Kaplan-Meier method to estimate patients' median survival time. We performed experiments in mice lacking EGFR in intestinal epithelial cells (Villin-Cre; Egfr and Villin-CreER; Egfr mice) or myeloid cells (LysM-Cre; Egfr mice) on a mixed background. These mice were bred with Apc mice; colitis-associated cancer and colitis were induced by administration of dextran sodium sulfate (DSS), with or without azoxymethane (AOM), respectively. Villin-CreER was activated in developed tumors by administration of tamoxifen to mice. Littermates that expressed full-length EGFR were used as controls. Intestinal tissues were collected; severity of colitis, numbers and size of tumors, and intestinal barrier integrity were assessed by histologic, immunohistochemical, quantitative reverse transcription polymerase chain reaction, and flow cytometry analyses. RESULTS:We detected EGFR in myeloid cells in the stroma of human colorectal tumors; myeloid cell expression of EGFR associated with tumor metastasis and shorter patient survival time. Mice with deletion of EGFR from myeloid cells formed significantly fewer and smaller tumors than the respective EGFR-expressing controls in an Apc background as well as after administration of AOM and DSS. Deletion of EGFR from intestinal epithelial cells did not affect tumor growth. Furthermore, tamoxifen-induced deletion of EGFR from epithelial cells of established intestinal tumors in mice given AOM and DSS did not reduce tumor size. EGFR signaling in myeloid cells promoted activation of STAT3 and expression of survivin in intestinal tumor cells. Mice with deletion of EGFR from myeloid cells developed more severe colitis after DSS administration, characterized by increased intestinal inflammation and intestinal barrier disruption, than control mice or mice with deletion of EGFR from intestinal epithelial cells. EGFR-deficient myeloid cells in the colon of DSS-treated LysM-Cre; Egfr mice had reduced expression of interleukin 6 (IL6), and epithelial STAT3 activation was reduced compared with controls. Administration of recombinant IL6 to LysM-Cre; Egfr mice given DSS protected them from weight loss and restored epithelial proliferation and STAT3 activation, compared with administration of DSS alone to these mice. CONCLUSIONS:Increased expression of EGFR in myeloid cells from the colorectal tumor stroma associates with tumor progression and reduced survival time of patients with metastatic colorectal cancer. Deletion of EGFR from myeloid cells, but not intestinal epithelial cells, protects mice from colitis-induced intestinal cancer and ApcMin-dependent intestinal tumorigenesis. Myeloid cell expression of EGFR increases activation of STAT3 and expression of survivin in intestinal epithelial cells and expression of IL6 in colon tissues. These findings indicate that expression of EGFR by myeloid cells of the colorectal tumor stroma, rather than the cancer cells themselves, contributes to tumor development.
The 'obligate diploid' Candida albicans forms mating-competent haploids.
Hickman Meleah A,Zeng Guisheng,Forche Anja,Hirakawa Matthew P,Abbey Darren,Harrison Benjamin D,Wang Yan-Ming,Su Ching-hua,Bennett Richard J,Wang Yue,Berman Judith
Candida albicans, the most prevalent human fungal pathogen, is considered to be an obligate diploid that carries recessive lethal mutations throughout the genome. Here we demonstrate that C. albicans has a viable haploid state that can be derived from diploid cells under in vitro and in vivo conditions, and that seems to arise through a concerted chromosome loss mechanism. Haploids undergo morphogenetic changes like those of diploids, including the yeast-hyphal transition, chlamydospore formation and a white-opaque switch that facilitates mating. Haploid opaque cells of opposite mating type mate efficiently to regenerate the diploid form, restoring heterozygosity and fitness. Homozygous diploids arise spontaneously by auto-diploidization, and both haploids and auto-diploids show a similar reduction in fitness, in vitro and in vivo, relative to heterozygous diploids, indicating that homozygous cell types are transient in mixed populations. Finally, we constructed stable haploid strains with multiple auxotrophies that will facilitate molecular and genetic analyses of this important pathogen.
Siblings of patients with Crohn's disease exhibit a biologically relevant dysbiosis in mucosal microbial metacommunities.
Hedin Charlotte,van der Gast Christopher J,Rogers Geraint B,Cuthbertson Leah,McCartney Sara,Stagg Andrew J,Lindsay James O,Whelan Kevin
OBJECTIVE:To determine the existence of mucosal dysbiosis in siblings of patients with Crohn's disease (CD) using 454 pyrosequencing and to comprehensively characterise and determine the influence of genotypical and phenotypical factors, on that dysbiosis. Siblings of patients with CD have elevated risk of developing CD and display aspects of disease phenotype, including faecal dysbiosis. Whether the mucosal microbiota is disrupted in these at-risk individuals is unknown. DESIGN:Rectal biopsy DNA was extracted from 21 patients with quiescent CD, 17 of their healthy siblings and 19 unrelated healthy controls. Mucosal microbiota was analysed by 16S rRNA gene pyrosequencing and were classified into core and rare species. Genotypical risk was determined using Illumina Immuno BeadChip, faecal calprotectin by ELISA and blood T-cell phenotype by flow cytometry. RESULTS:Core microbiota of both patients with CD and healthy siblings was significantly less diverse than controls. Metacommunity profiling (Bray-Curtis (SBC) index) showed the sibling core microbial composition to be more similar to CD (SBC=0.70) than to healthy controls, whereas the sibling rare microbiota was more similar to healthy controls (SBC=0.42). Faecalibacterium prausnitzii contributed most to core metacommunity dissimilarity both between siblings and controls, and between patients and controls. Phenotype/genotype markers of CD risk significantly influenced microbiota variation between and within groups, of which genotype had the largest effect. CONCLUSIONS:Individuals with elevated CD-risk display mucosal dysbiosis characterised by reduced diversity of core microbiota and lower abundance of F. prausnitzii. This dysbiosis in healthy people at risk of CD implicates microbiological processes in CD pathogenesis.
A Role for cis Interaction between the Inhibitory Ly49A receptor and MHC class I for natural killer cell education.
Chalifour Anick,Scarpellino Léonardo,Back Jonathan,Brodin Petter,Devèvre Estelle,Gros Frédéric,Lévy Frédéric,Leclercq Georges,Höglund Petter,Beermann Friedrich,Held Werner
Natural killer (NK) cells show enhanced functional competence when they express inhibitory receptors specific for inherited major histocompatibility complex class I (MHC-I) molecules. Current models imply that NK cell education requires an interaction of inhibitory receptors with MHC-I expressed on other cells. However, the inhibitory Ly49A receptor can also bind MHC-I ligand on the NK cell itself (in cis). Here we describe a Ly49A variant, which can engage MHC-I expressed on other cells but not in cis. Even though this variant inhibited NK cell effector function, it failed to educate NK cells. The association with MHC-I in cis sequestered wild-type Ly49A, and this was found to relieve NK cells from a suppressive effect of unengaged Ly49A. These data explain how inhibitory MHC-I receptors can facilitate NK cell activation. They dissociate classical inhibitory from educating functions of Ly49A and suggest that cis interaction of Ly49A is necessary for NK cell education.
Hepatic interleukin-7 expression regulates T cell responses.
Sawa Yukihisa,Arima Yasunobu,Ogura Hideki,Kitabayashi Chika,Jiang Jing-Jing,Fukushima Toru,Kamimura Daisuke,Hirano Toshio,Murakami Masaaki
Systemic cytokine activity in response to Toll-like receptor (TLR) signaling induces the expression of various proteins in the liver after infections. Here we show that Interleukin-7 (IL-7), the production of which was thought to occur at a constant rate in vivo, was a hepatically expressed protein that directly controled T cell responses. Depletion of IL-7 expression in the liver abrogated several TLR-mediated T cell events, including enhanced CD4+ T cell and CD8+ T cell survival, augmented CD8+ T cell cytotoxic activity, and the development of experimental autoimmune encephalitis, a Th17 cell-mediated autoimmune disease. Thus, T cell responses are regulated by hepatocyte-derived IL-7, which is expressed in response to TLR signaling in vivo. We suggested that TLR-induced IL-7 expression in the liver, which is an acute-phase response, may be a good diagnostic and therapeutic target for efficient vaccine developments and for conditions characterized by TLR-mediated T cell dysregulation, including autoimmune diseases.
Uncoupling immune trajectories of response and adverse events from anti-PD-1 immunotherapy in hepatocellular carcinoma.
Journal of hepatology
BACKGROUND & AIMS:While immune checkpoint blockade (ICB) has shown promise in patients with hepatocellular carcinoma (HCC), it is associated with modest response rates and immune-related adverse events (irAEs) are common. In this study, we aimed to decipher immune trajectories and mechanisms of response and/or irAEs in patients with HCC receiving anti-programmed cell death 1 (anti-PD-1) therapy. METHODS:Pre- and on-treatment peripheral blood samples (n = 60) obtained from 32 patients with HCC (Singapore cohort) were analysed by cytometry by time-of-flight and single-cell RNA sequencing, with flow cytometric validation in an independent Korean cohort (n = 29). Mechanistic validation was conducted by bulk RNA sequencing of 20 pre- and on-treatment tumour biopsies and using a murine HCC model treated with different immunotherapeutic combinations. RESULTS:Single-cell analyses identified CXCR3CD8 effector memory T (T) cells and CD11c antigen-presenting cells (APC) as associated with response (p = 0.0004 and 0.0255, respectively), progression-free survival (p = 0.00079 and 0.0015, respectively), and irAEs (p = 0.0034 and 0.0125, respectively) in anti-PD-1-treated patients with HCC. Type-1 conventional dendritic cells were identified as the specific APC associated with response, while 2 immunosuppressive CD14 myeloid clusters were linked to reduced irAEs. Further analyses of CXCR3CD8 T cells showed cell-cell interactions specific to response vs. irAEs, from which the anti-PD-1 and anti-TNFR2 combination was harnessed to uncouple these effects, resulting in enhanced response without increased irAEs in a murine HCC model. CONCLUSIONS:This study identifies early predictors of clinical response to anti-PD-1 ICB in patients with HCC and offers mechanistic insights into the immune trajectories of these immune subsets at the interface between response and toxicity. We also propose a new combination immunotherapy for HCC to enhance response without exacerbating irAEs. CLINICAL TRIAL NUMBER:NCT03695952. LAY SUMMARY:Response rates to immune checkpoint blockade (ICB) treatment in hepatocellular carcinoma (HCC) remain modest and adverse events are common. Herein, we identified early predictors of response and gained an in-depth understanding of the immunological mechanisms behind response and adverse events in patients with HCC treated with ICB. We also proposed a new combination immunotherapy for HCC that enhances response without exacerbating adverse events.
Extensive hematopoietic stem cell generation in the AGM region via maturation of VE-cadherin+CD45+ pre-definitive HSCs.
Taoudi Samir,Gonneau Christèle,Moore Kate,Sheridan Julie M,Blackburn C Clare,Taylor Erin,Medvinsky Alexander
Cell stem cell
Elucidating the mechanisms underlying hematopoietic stem cell (HSC) specification and expansion in the embryo has been hampered by the lack of analytical cell culture systems that recapitulate in vivo development. Here, we describe an ex vivo model that facilitates a rapid and robust emergence of multipotent long-term repopulating HSCs in the embryonic AGM region. Because this method includes a cell dissociation step prior to reconstruction of a three-dimensional functional tissue and preserves both stromal and hematopoietic elements, it allowed us to identify the direct ancestry of the rapidly expanding HSC pool. We demonstrate that extensive generation of definitive HSCs in the AGM occurs predominantly through the acquisition of stem characteristics by the VE-cadherin+CD45+ population.
Labile catalytic packaging of DNA/siRNA: control of gold nanoparticles "out" of DNA/siRNA complexes.
Chen Alex M,Taratula Oleh,Wei Dongguang,Yen Hsin-I,Thomas Thresia,Thomas T J,Minko Tamara,He Huixin
A novel approach was developed to efficiently package and deliver nucleic acids with low generation polypropylenimine (PPI) dendrimers by using Au nanoparticles as a "labile catalytic" packaging agent. The gold nanoparticles (Au NPs) helped low generation dendrimers to package nucleic acids into discrete nanoparticles but are not included in the final DNA/siRNA complexes. Therefore it becomes possible to eliminate the potential toxic problems associated with Au NPs by selectively removing the Au NPs from the resulting nucleic acid complexes before their delivery to targeted cells. This is a new concept in using inorganic engineered nanoparticles in nucleic acid packaging and delivery applications. Furthermore, compared to the siRNA nanostructures (mainly randomly aggregated nanofibers) fabricated by low generation dendrimer alone (Generation 3), the siRNA nanoparticles packaged using this novel approach (by Au NPs modified with G3 PPI) can be internalized by cancer cells and the delivered siRNAs can efficiently silence their target mRNA. The efficiency of mRNA silencing by this novel approach is even superior to higher generation dendrimers (Generation 5).
An essential role of the Forkhead-box transcription factor Foxo1 in control of T cell homeostasis and tolerance.
Ouyang Weiming,Beckett Omar,Flavell Richard A,Li Ming O
Members of the Forkhead box O (Foxo) family of transcription factors are key regulators of cellular responses, but their function in the immune system remains incompletely understood. Here we showed that T cell-specific deletion of Foxo1 gene in mice led to spontaneous T cell activation, effector T cell differentiation, autoantibody production, and the induction of inflammatory bowel disease in a transfer model. In addition, Foxo1 was critical for the maintenance of naive T cells in the peripheral lymphoid organs. Transcriptome analyses of T cells identified Foxo1-regulated genes encoding, among others, cell-surface molecules, signaling proteins, and nuclear factors that control gene expression. Functional studies validated interleukin-7 receptor-alpha as a Foxo1 target gene essential for Foxo1 maintenance of naive T cells. These findings reveal crucial functions of Foxo1-dependent transcription in control of T cell homeostasis and tolerance.
Inhibition of JAK-STAT Signaling Suppresses Pathogenic Immune Responses in Medium and Large Vessel Vasculitis.
Zhang Hui,Watanabe Ryu,Berry Gerald J,Tian Lu,Goronzy Jörg J,Weyand Cornelia M
BACKGROUND:Giant cell arteritis, a chronic autoimmune disease of the aorta and its large branches, is complicated by aneurysm formation, dissection, and arterial occlusions. Arterial wall dendritic cells attract CD4 T cells and macrophages to form prototypic granulomatous infiltrates. Vasculitic lesions contain a diverse array of effector T cells that persist despite corticosteroid therapy and sustain chronic, smoldering vasculitis. Transmural inflammation induces microvascular neoangiogenesis and results in lumen-occlusive intimal hyperplasia. We have examined whether persistent vessel wall inflammation is maintained by lesional T cells, including the newly identified tissue-resident memory T cells, and whether such T cells are sensitive to the cytokine-signaling inhibitor tofacitinib, a Janus kinase (JAK) inhibitor targeting JAK3 and JAK1. METHODS:Vascular inflammation was induced in human arteries engrafted into immunodeficient mice that were reconstituted with T cells and monocytes from patients with giant cell arteritis. Mice carrying inflamed human arteries were treated with tofacitinib or vehicle. Vasculitic arteries were examined for gene expression (reverse transcription polymerase chain reaction), protein expression (immunohistochemistry), and infiltrating cell populations (flow cytometry). RESULTS:Tofacitinib effectively suppressed innate and adaptive immunity in the vessel wall. Lesional T cells responded to tofacitinib with reduced proliferation rates (<10%) and minimal production of the effector molecules interferon-γ, interleukin-17, and interleukin-21. Tofacitinib disrupted adventitial microvascular angiogenesis, reduced outgrowth of hyperplastic intima, and minimized CD4CD103 tissue-resident memory T cells. CONCLUSIONS:Cytokine signaling dependent on JAK3 and JAK1 is critically important in chronic inflammation of medium and large arteries. The JAK inhibitor tofacitinib effectively suppresses tissue-resident memory T cells and inhibits core vasculitogenic effector pathways.
Fc receptor gamma-chain, a constitutive component of the IL-3 receptor, is required for IL-3-induced IL-4 production in basophils.
Hida Shigeaki,Yamasaki Sho,Sakamoto Yuzuru,Takamoto Masaya,Obata Kazushige,Takai Toshiyuki,Karasuyama Hajime,Sugane Kazuo,Saito Takashi,Taki Shinsuke
The Fc receptor common gamma-chain (FcRgamma) is a widely expressed adaptor bearing an immunoreceptor tyrosine-based activation motif (ITAM) that transduces activation signals from various immunoreceptors. We show here that basophils lacking FcRgamma developed normally and proliferated efficiently in response to interleukin 3 (IL-3) but were very impaired in IL-3-induced production of IL-4 and in supporting T helper type 2 differentiation. Through its transmembrane portion, FcRgamma associated constitutively with the common beta-chain of the IL-3 receptor and signaled by recruiting the kinase Syk. Retrovirus-mediated complementation demonstrated the essential function of the ITAM of FcRgamma in IL-3 signal transduction. Our results identify a previously unknown mechanism whereby FcRgamma functions to 'route' selective cytokine-triggered signals into the ITAM-mediated IL-4 production pathway.
Hypoxia-inducible factor-dependent induction of netrin-1 dampens inflammation caused by hypoxia.
Rosenberger Peter,Schwab Jan M,Mirakaj Valbona,Masekowsky Eva,Mager Alice,Morote-Garcia Julio C,Unertl Klaus,Eltzschig Holger K
The neuronal guidance molecule netrin-1 is linked to the coordination of inflammatory responses. Given that mucosal surfaces are particularly prone to hypoxia-elicited inflammation, we sought to determine the function of netrin-1 in hypoxia-induced inflammation. We detected hypoxia-inducible factor 1alpha (HIF-1alpha)-dependent induction of expression of the gene encoding netrin-1 (Ntn1) in hypoxic epithelia. Neutrophil transepithelial migration studies showed that by engaging A2B adenosine receptor (A2BAR) on neutrophils, netrin-1 attenuated neutrophil transmigration. Exogenous netrin-1 suppressed hypoxia-elicited inflammation in wild-type but not in A2BAR-deficient mice, and inflammatory hypoxia was enhanced in Ntn1(+/-) mice relative to that in Ntn1(+/+) mice. Our studies demonstrate that HIF-1alpha-dependent induction of netrin-1 attenuates hypoxia-elicited inflammation at mucosal surfaces.
Identification of a new subset of myeloid suppressor cells in peripheral blood of melanoma patients with modulation by a granulocyte-macrophage colony-stimulation factor-based antitumor vaccine.
Filipazzi Paola,Valenti Roberta,Huber Veronica,Pilla Lorenzo,Canese Paola,Iero Manuela,Castelli Chiara,Mariani Luigi,Parmiani Giorgio,Rivoltini Licia
Journal of clinical oncology : official journal of the American Society of Clinical Oncology
PURPOSE:Phenotypic and functional features of myeloid suppressor cells (MSC), which are known to serve as critical regulators of antitumor T-cell responses in tumor-bearing mice, are still poorly defined in human cancers. Here, we analyzed myeloid subsets with suppressive activity present in peripheral blood of metastatic melanoma patients and evaluated their modulation by a granulocyte-macrophage colony-stimulating factor (GM-CSF)--based antitumor vaccine. PATIENTS AND METHODS:Stage IV metastatic melanoma patients (n = 16) vaccinated with autologous tumor-derived heat shock protein peptide complex gp96 (HSPPC-96) and low-dose GM-CSF provided pre- and post-treatment whole blood specimens. Peripheral-blood mononuclear cells (PBMCs) were analyzed by flow cytometry, separated into cellular subsets, and used for in vitro proliferation assays. PBMCs from stage-matched metastatic melanoma patients (n = 12) treated with non-GM-CSF-based vaccines (ie, HSPPC-96 alone or interferon alfa/melanoma-derived peptides) or sex- and age-matched healthy donors (n = 16) were also analyzed for comparison. RESULTS:The lack of or low HLA-DR expression was found to identify a CD14+ cell subset highly suppressive of lymphocyte functions. CD14+HLA-DR-/lo cells were significantly expanded in all metastatic melanoma patients, whereas they were undetectable in healthy donors. Suppressive activity was mediated by transforming growth factor beta (TGF-beta), whereas no involvement of the arginase and inducible nitric oxide synthase pathways could be detected. CD14+HLA-DR-/lo cells, as well as spontaneous ex vivo release and plasma levels of TGF-beta, were augmented after administration of the HSPPC-96/GM-CSF vaccine. No enhancement of the CD14+-mediated suppressive activity was found in patients receiving non-GM-CSF-based vaccines. CONCLUSION:CD14+HLA-DR-/lo cells exerting TGF-beta-mediated immune suppression represent a new subset of MSC potentially expandable by the administration of GM-CSF-based vaccines in metastatic melanoma patients.
Hyperglycemia Increases Interstitial Cells of Cajal via MAPK1 and MAPK3 Signaling to ETV1 and KIT, Leading to Rapid Gastric Emptying.
Hayashi Yujiro,Toyomasu Yoshitaka,Saravanaperumal Siva Arumugam,Bardsley Michael R,Smestad John A,Lorincz Andrea,Eisenman Seth T,Cipriani Gianluca,Nelson Holte Molly H,Al Khazal Fatimah J,Syed Sabriya A,Gajdos Gabriella B,Choi Kyoung Moo,Stoltz Gary J,Miller Katie E,Kendrick Michael L,Rubin Brian P,Gibbons Simon J,Bharucha Adil E,Linden David R,Maher Louis James,Farrugia Gianrico,Ordog Tamas
BACKGROUND & AIMS:Depletion of interstitial cells of Cajal (ICCs) is common in diabetic gastroparesis. However, in approximately 20% of patients with diabetes, gastric emptying (GE) is accelerated. GE also occurs faster in obese individuals, and is associated with increased blood levels of glucose in patients with type 2 diabetes. To understand the fate of ICCs in hyperinsulinemic, hyperglycemic states characterized by rapid GE, we studied mice with mutation of the leptin receptor (Lepr), which in our colony had accelerated GE. We also investigated hyperglycemia-induced signaling in the ICC lineage and ICC dependence on glucose oxidative metabolism in mice with disruption of the succinate dehydrogenase complex, subunit C gene (Sdhc). METHODS:Mice were given breath tests to analyze GE of solids. ICCs were studied by flow cytometry, intracellular electrophysiology, isometric contractility measurement, reverse-transcription polymerase chain reaction, immunoblot, immunohistochemistry, enzyme-linked immunosorbent assays, and metabolite assays; cells and tissues were manipulated pharmacologically and by RNA interference. Viable cell counts, proliferation, and apoptosis were determined by methyltetrazolium, Ki-67, proliferating cell nuclear antigen, bromodeoxyuridine, and caspase-Glo 3/7 assays. Sdhc was disrupted in 2 different strains of mice via cre recombinase. RESULTS:In obese, hyperglycemic, hyperinsulinemic female Lepr mice, GE was accelerated and gastric ICC and phasic cholinergic responses were increased. Female Kit mice, which have genetically induced hyperplasia of ICCs, also had accelerated GE. In isolated cells of the ICC lineage and gastric organotypic cultures, hyperglycemia stimulated proliferation by mitogen-activated protein kinase 1 (MAPK1)- and MAPK3-dependent stabilization of ets variant 1-a master transcription factor for ICCs-and consequent up-regulation of v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) receptor tyrosine kinase. Opposite changes occurred in mice with disruption of Sdhc. CONCLUSIONS:Hyperglycemia increases ICCs via oxidative metabolism-dependent, MAPK1- and MAPK3-mediated stabilization of ets variant 1 and increased expression of KIT, causing rapid GE. Increases in ICCs might contribute to the acceleration in GE observed in some patients with diabetes.
EpCAM, a new marker for cancer stem cells in hepatocellular carcinoma.
Terris Benoit,Cavard Catherine,Perret Christine
Journal of hepatology
BACKGROUND & AIMS:Cancer progression/metastases and embryonic development share many properties including cellular plasticity, dynamic cell motility, and integral interaction with the microenvironment. We hypothesized that the heterogeneous nature of hepatocellular carcinoma (HCC), in part, may be owing to the presence of hepatic cancer cells with stem/progenitor features. METHODS:Gene expression profiling and immunohistochemistry analyses were used to analyze 235 tumor specimens derived from 2 recently identified HCC subtypes (EpCAM(+) alpha-fetoprotein [AFP(+)] HCC and EpCAM(-) AFP(-) HCC). These subtypes differed in their expression of AFP, a molecule produced in the developing embryo, and EpCAM, a cell surface hepatic stem cell marker. Fluorescence-activated cell sorting was used to isolate EpCAM(+) HCC cells, which were tested for hepatic stem/progenitor cell properties. RESULTS:Gene expression and pathway analyses revealed that the EpCAM(+) AFP(+) HCC subtype had features of hepatic stem/progenitor cells. Indeed, the fluorescence-activated cell sorting-isolated EpCAM(+) HCC cells displayed hepatic cancer stem cell-like traits including the abilities to self-renew and differentiate. Moreover, these cells were capable of initiating highly invasive HCC in nonobese diabetic, severe combined immunodeficient mice. Activation of Wnt/beta-catenin signaling enriched the EpCAM(+) cell population, whereas RNA interference-based blockage of EpCAM, a Wnt/beta-catenin signaling target, attenuated the activities of these cells. CONCLUSIONS:Taken together, our results suggest that HCC growth and invasiveness is dictated by a subset of EpCAM(+) cells, opening a new avenue for HCC cancer cell eradication by targeting Wnt/beta-catenin signaling components such as EpCAM.
Autoimmune skin inflammation is dependent on plasmacytoid dendritic cell activation by nucleic acids via TLR7 and TLR9.
Guiducci Cristiana,Tripodo Claudio,Gong Mei,Sangaletti Sabina,Colombo Mario P,Coffman Robert L,Barrat Franck J
The Journal of experimental medicine
Recognition of endogenous DNA and RNA by cells expressing TLR7 and TLR9 is an important contributor to the pathogenesis of systemic lupus erythematosus and has been suggested to contribute to cutaneous lupus and to a group of related inflammatory skin diseases termed interface dermatitis. We have developed a mouse model of TLR7- and TLR9-dependent skin inflammation using tape stripping. In normal mice, this resulted in a rapid but transient inflammatory cell infiltration accompanied by induction of type I IFN production by plasmacytoid dendritic cells (PDCs) and release of extracellular traps and proinflammatory cytokines by neutrophils. These responses were strongly reduced in MyD88-deficient mice and in mice treated with a bifunctional inhibitor of TLR7 and TLR9. In contrast, in lupus-prone (NZBxNZW)F(1) mice, tape stripping induced the development of chronic lesions characterized by a persistent type I IFN gene signature and many clinical and histological features of cutaneous lupus. Depletion of PDCs before injury prevented the development of skin lesions, whereas treatment with a bifunctional TLR7/9 inhibitor before tape stripping or after the initial lesion was established led to a significant reduction of the disease. These data suggest that inhibitors of TLR7 and TLR9 signaling have potential therapeutic application for the treatment of interface dermatitis.
Chemorepulsion by blood S1P regulates osteoclast precursor mobilization and bone remodeling in vivo.
Ishii Masaru,Kikuta Junichi,Shimazu Yutaka,Meier-Schellersheim Martin,Germain Ronald N
The Journal of experimental medicine
Sphingosine-1-phosphate (S1P), a lipid mediator enriched in blood, controls the dynamic migration of osteoclast (OC) precursors (OPs) between the blood and bone, in part via the S1P receptor 1 (S1PR1) which directs positive chemotaxis toward S1P. We show that OPs also express S1PR2, an S1P receptor which mediates negative chemotaxis (or chemorepulsion). OP-positive chemotaxis is prominent in gradients with low maximal concentrations of S1P, whereas such behavior is minimal in fields with high maximal S1P concentrations. This reverse-directional behavior is caused by S1PR2-mediated chemorepulsion acting to override S1PR1 upgradient motion. S1PR2-deficient mice exhibit moderate osteopetrosis as a result of a decrease in osteoclastic bone resorption, suggesting that S1PR2 contributes to OP localization on the bones mediated by chemorepulsion away from the blood where S1P levels are high. Inhibition of S1PR2 function by the antagonist JTE013 changed the migratory behavior of monocytoid cells, including OPs, and relieved osteoporosis in a mouse model by limiting OP localization and reducing the number of mature OCs attached to the bone surface. Thus, reciprocal regulation of S1P-dependent chemotaxis controls bone remodeling by finely regulating OP localization. This regulatory axis may be promising as a therapeutic target in diseases affecting OC-dependent bone remodeling.
The costimulatory molecule ICOS regulates the expression of c-Maf and IL-21 in the development of follicular T helper cells and TH-17 cells.
Bauquet Aurelie T,Jin Hulin,Paterson Alison M,Mitsdoerffer Meike,Ho I-Cheng,Sharpe Arlene H,Kuchroo Vijay K
The inducible costimulatory molecule ICOS has been suggested to be important in the development of interleukin 17 (IL-17)-producing helper T cells (T(H)-17 cells) and of follicular helper T cells (T(FH) cells). Here we show that ICOS-deficient mice had no defect in T(H)-17 differentiation but had fewer T(H)-17 cells after IL-23 stimulation and fewer T(FH) cells. We also show that T(FH) cells produced IL-17 and that T(FH) cells in ICOS-deficient mice were defective in IL-17 production. Both T(H)-17 and T(FH) cells had higher expression of the transcription factor c-Maf. Genetic loss of c-Maf resulted in a defect in IL-21 production and fewer T(H)-17 and T(FH) cells. Thus our data suggest that ICOS-induced c-Maf regulates IL-21 production that in turn regulates the expansion of T(H)-17 and T(FH) cells.
The kinase PDK1 integrates T cell antigen receptor and CD28 coreceptor signaling to induce NF-kappaB and activate T cells.
Park Sung-Gyoo,Schulze-Luehrman Jan,Hayden Matthew S,Hashimoto Naoko,Ogawa Wataru,Kasuga Masato,Ghosh Sankar
In addition to ligation of the T cell antigen receptor (TCR), activation of the CD28 coreceptor by the costimulatory molecule B7 is required for induction of the transcription factor NF-kappaB and robust T cell activation, although the contribution of CD28 to this process remains incompletely understood. We show here that phosphoinositide-dependent kinase 1 (PDK1) is essential for integrating the TCR and CD28 signals. After we deleted PDK1 from T cells, TCR-CD28 signals were unable to induce activation of NF-kappaB or phosphorylation of protein kinase C-theta, although T cell survival and pathways dependent on the kinases p38 and Jnk or the transcription factor NFAT were unaffected. CD28 facilitated NF-kappaB activation by regulating recruitment and phosphorylation of PDK1, which are necessary for efficient binding of PDK1 to protein kinase C-theta and the adaptor CARMA1 and thus for NF-kappaB induction.
Foxo1 links homing and survival of naive T cells by regulating L-selectin, CCR7 and interleukin 7 receptor.
Kerdiles Yann M,Beisner Daniel R,Tinoco Roberto,Dejean Anne S,Castrillon Diego H,DePinho Ronald A,Hedrick Stephen M
Foxo transcription factors have a conserved role in the adaptation of cells and organisms to nutrient and growth factor availability. Here we show that Foxo1 has a crucial, nonredundant role in T cells. In naive T cells, Foxo1 controlled the expression of the adhesion molecule L-selectin, the chemokine receptor CCR7 and the transcription factor Klf2, and its deletion was sufficient to alter lymphocyte trafficking. Furthermore, Foxo1 deficiency resulted in a severe defect in interleukin 7 receptor alpha-chain (IL-7Ralpha) expression associated with its ability to bind an Il7r enhancer. Finally, growth factor withdrawal induced a Foxo1-dependent increase in Sell, Klf2 and Il7r expression. These data suggest that Foxo1 regulates the homeostasis and life span of naive T cells by sensing growth factor availability and regulating homing and survival signals.
The cell cycle related apoptotic susceptibility to arsenic trioxide is associated with the level of reactive oxygen species.
Gao Fei,Yi Jing,Yuan Jing Qi,Shi Gui Ying,Tang Xue Ming
Double staining flow cytometry was performed using 7-amino actinomycin D and 6-carboxy-2', 7'-dichlorodihydrofluorescein diacetate, to detect the level fluctuation of reactive oxygen species (ROS) during the cell cycle of normal NB4 cells. Our results showed that NB4 cells possessed higher level of ROS in G2/M phase than in G1 and S phases. Double staining flow cytometry, with TdT mediated dUTP nick end labeling (Tunel) and propidium iodide (PI), indicated that As2O3 (2 microM) could induce apoptosis in NB4 cells prevailingly from G2/M phase, and this efficacy was enhanced upon co-administration of 2, 3-dimethoxy-1, 4-naphthoquinone (DMNQ) (2.5 microM) which could produce the endogenous ROS. These results suggested that different ROS level in different cell cycle phases of NB4 cells might determine the selective induction of G2/M apoptosis and the cells' susceptibility to apoptosis by As2O3.
IL-27 supports germinal center function by enhancing IL-21 production and the function of T follicular helper cells.
Batten Marcel,Ramamoorthi Nandhini,Kljavin Noelyn M,Ma Cindy S,Cox Jennifer H,Dengler Hart S,Danilenko Dimitry M,Caplazi Patrick,Wong Melanie,Fulcher David A,Cook Matthew C,King Cecile,Tangye Stuart G,de Sauvage Frederic J,Ghilardi Nico
The Journal of experimental medicine
Maturation and selection of high-affinity B cell clones in the germinal center (GC) relies on support from T follicular helper (T(FH)) cells. T(FH) cells are characterized by their localization to the B cell follicle and their high expression of the costimulatory molecules ICOS and PD1 and the cytokine IL-21, which promotes immunoglobulin (Ig) class switching and production by B cells. We show that the heterodimeric cytokine IL-27 is critical for the function of T(FH) cells and for normal and pathogenic GC responses. IL-27 signaling to T cells results in the production of IL-21, a known autocrine factor for the maintenance of T(FH) cells, in a STAT3-dependent manner. IL-27 also enhances the survival of activated CD4(+) T cells and the expression of T(FH) cell phenotypic markers. In vivo, expression of the IL-27Rα chain is required to support IL-21 production and T(FH) cell survival in a T cell-intrinsic manner. The production of high-affinity antibodies is reduced, and pristane-elicited autoantibodies and glomerulonephritis are significantly diminished, in Il27ra(-/-) mice. Together, our data show a nonredundant role for IL-27 in the development of T cell-dependent antibody responses.
Transient activation of c-MYC expression is critical for efficient platelet generation from human induced pluripotent stem cells.
Takayama Naoya,Nishimura Satoshi,Nakamura Sou,Shimizu Takafumi,Ohnishi Ryoko,Endo Hiroshi,Yamaguchi Tomoyuki,Otsu Makoto,Nishimura Ken,Nakanishi Mahito,Sawaguchi Akira,Nagai Ryozo,Takahashi Kazutoshi,Yamanaka Shinya,Nakauchi Hiromitsu,Eto Koji
The Journal of experimental medicine
Human (h) induced pluripotent stem cells (iPSCs) are a potentially abundant source of blood cells, but how best to select iPSC clones suitable for this purpose from among the many clones that can be simultaneously established from an identical source is not clear. Using an in vitro culture system yielding a hematopoietic niche that concentrates hematopoietic progenitors, we show that the pattern of c-MYC reactivation after reprogramming influences platelet generation from hiPSCs. During differentiation, reduction of c-MYC expression after initial reactivation of c-MYC expression in selected hiPSC clones was associated with more efficient in vitro generation of CD41a(+)CD42b(+) platelets. This effect was recapitulated in virus integration-free hiPSCs using a doxycycline-controlled c-MYC expression vector. In vivo imaging revealed that these CD42b(+) platelets were present in thrombi after laser-induced vessel wall injury. In contrast, sustained and excessive c-MYC expression in megakaryocytes was accompanied by increased p14 (ARF) and p16 (INK4A) expression, decreased GATA1 expression, and impaired production of functional platelets. These findings suggest that the pattern of c-MYC expression, particularly its later decline, is key to producing functional platelets from selected iPSC clones.
Preferential infection and depletion of Mycobacterium tuberculosis-specific CD4 T cells after HIV-1 infection.
Geldmacher Christof,Ngwenyama Njabulo,Schuetz Alexandra,Petrovas Constantinos,Reither Klaus,Heeregrave Edwin J,Casazza Joseph P,Ambrozak David R,Louder Mark,Ampofo William,Pollakis Georgios,Hill Brenna,Sanga Erica,Saathoff Elmar,Maboko Leonard,Roederer Mario,Paxton William A,Hoelscher Michael,Koup Richard A
The Journal of experimental medicine
HIV-1 infection results in the progressive loss of CD4 T cells. In this study, we address how different pathogen-specific CD4 T cells are affected by HIV infection and the cellular parameters involved. We found striking differences in the depletion rates between CD4 T cells to two common opportunistic pathogens, cytomegalovirus (CMV) and Mycobacterium tuberculosis (MTB). CMV-specific CD4 T cells persisted after HIV infection, whereas MTB-specific CD4 T cells were depleted rapidly. CMV-specific CD4 T cells expressed a mature phenotype and produced very little IL-2, but large amounts of MIP-1β. In contrast, MTB-specific CD4 T cells were less mature, and most produced IL-2 but not MIP-1β. Staphylococcal enterotoxin B-stimulated IL-2-producing cells were more susceptible to HIV infection in vitro than MIP-1β-producing cells. Moreover, IL-2 production was associated with expression of CD25, and neutralization of IL-2 completely abrogated productive HIV infection in vitro. HIV DNA was found to be most abundant in IL-2-producing cells, and least abundant in MIP-1β-producing MTB-specific CD4 T cells from HIV-infected subjects with active tuberculosis. These data support the hypothesis that differences in function affect the susceptibility of pathogen-specific CD4 T cells to HIV infection and depletion in vivo, providing a potential mechanism to explain the rapid loss of MTB-specific CD4 T cells after HIV infection.
A peripheral CD4+ T cell precursor for naive, memory, and regulatory T cells.
Zhao Chunfang,Davies Joanna D
The Journal of experimental medicine
Mechanisms that control the size of the T cell pool, the ratio between naive cells and memory cells, the number and frequency of regulatory T cells, and T cell receptor (TCR) diversity are necessary to maintain immune integrity and avoid disease. We have previously shown that a subset of naive CD4(+) T cells, defined by the expression on their surface of a very low density of CD44 (CD44(v.low) cells), can inhibit wasting and wasting-associated lymphopenia in mice with cancer. In this study, we further investigate the properties of CD44(v.low) cells and show that they are significantly more efficient than the remaining naive (CD44(low) or CD44(int)) and memory CD4(+) cell subsets in reconstituting the overall size of the CD4(+) T cell pool, creating a T cell pool with a diverse TCR repertoire, generating regulatory T cells that express forkhead box P3 (FoxP3), and promoting homeostatic equilibrium between naive, memory, and Foxp3(+) regulatory T cell numbers. T cell population reconstitution by CD44(v.low) cells is thymus independent. Compared with CD44(int) cells, a higher percentage of CD44(v.low) cells express B cell leukemia/lymphoma 2, interleukin-7 receptor, and CD5. The data support a key role for CD4(+) CD44(v.low) cells as peripheral precursors that maintain the integrity of the CD4(+) T cell pool.
Deficiency of the oxygen sensor prolyl hydroxylase 1 attenuates hypercholesterolaemia, atherosclerosis, and hyperglycaemia.
Marsch Elke,Demandt Jasper A F,Theelen Thomas L,Tullemans Bibian M E,Wouters Kristiaan,Boon Mariëtte R,van Dijk Theo H,Gijbels Marion J,Dubois Ludwig J,Meex Steven J R,Mazzone Massimiliano,Hung Gene,Fisher Edward A,Biessen Erik A L,Daemen Mat J A P,Rensen Patrick C N,Carmeliet Peter,Groen Albert K,Sluimer Judith C
European heart journal
AIMS:Normalization of hypercholesterolaemia, inflammation, hyperglycaemia, and obesity are main desired targets to prevent cardiovascular clinical events. Here we present a novel regulator of cholesterol metabolism, which simultaneously impacts on glucose intolerance and inflammation. METHODS AND RESULTS:Mice deficient for oxygen sensor HIF-prolyl hydroxylase 1 (PHD1) were backcrossed onto an atherogenic low-density lipoprotein receptor (LDLR) knockout background and atherosclerosis was studied upon 8 weeks of western-type diet. PHD1LDLR mice presented a sharp reduction in VLDL and LDL plasma cholesterol levels. In line, atherosclerotic plaque development, as measured by plaque area, necrotic core expansion and plaque stage was hampered in PHD1LDLR mice. Mechanistically, cholesterol-lowering in PHD1 deficient mice was a result of enhanced cholesterol excretion from blood to intestines and ultimately faeces. Additionally, flow cytometry of whole blood of these mice revealed significantly reduced counts of leucocytes and particularly of Ly6C pro-inflammatory monocytes. In addition, when studying PHD1 in diet-induced obesity (14 weeks high-fat diet) mice were less glucose intolerant when compared with WT littermate controls. CONCLUSION:Overall, PHD1 knockout mice display a metabolic phenotype that generally is deemed protective for cardiovascular disease. Future studies should focus on the efficacy, safety, and gender-specific effects of PHD1 inhibition in humans, and unravel the molecular actors responsible for PHD1-driven, likely intestinal, and regulation of cholesterol metabolism.
Characterization of the human neutrophil alloantigen-3a.
Greinacher Andreas,Wesche Jan,Hammer Elke,Fürll Birgitt,Völker Uwe,Reil Angelika,Bux Jürgen
Transfusion-related acute lung injury (TRALI) is a frequent cause of transfusion-associated morbidity and mortality. Severe TRALI is often due to antibodies in blood components directed against the human neutrophil alloantigen-3a (HNA-3a). We show here that the HNA-3a antigen arises from a nucleotide polymorphism in the choline transporter-like protein-2 gene (SLC44A2), with the resulting variation at amino acid position 154 determining the reactivity of the protein with HNA-3a-specific antibodies; the variant with an arginine at this position, rather than a glutamine, constitutes the HNA-3a antigen. The molecular identification of this antigen should facilitate the development of assays for blood donor screening to lower the risk of TRALI.
Deconstructing pancreas developmental biology.
Benitez Cecil M,Goodyer William R,Kim Seung K
Cold Spring Harbor perspectives in biology
The relentless nature and increasing prevalence of human pancreatic diseases, in particular, diabetes mellitus and adenocarcinoma, has motivated further understanding of pancreas organogenesis. The pancreas is a multifunctional organ whose epithelial cells govern a diversity of physiologically vital endocrine and exocrine functions. The mechanisms governing the birth, differentiation, morphogenesis, growth, maturation, and maintenance of the endocrine and exocrine components in the pancreas have been discovered recently with increasing tempo. This includes recent studies unveiling mechanisms permitting unexpected flexibility in the developmental potential of immature and mature pancreatic cell subsets, including the ability to interconvert fates. In this article, we describe how classical cell biology, genetic analysis, lineage tracing, and embryological investigations are being complemented by powerful modern methods including epigenetic analysis, time-lapse imaging, and flow cytometry-based cell purification to dissect fundamental processes of pancreas development.
Silencing or inhibition of endoplasmic reticulum aminopeptidase 1 (ERAP1) suppresses free heavy chain expression and Th17 responses in ankylosing spondylitis.
Chen Liye,Ridley Anna,Hammitzsch Ariane,Al-Mossawi Mohammad Hussein,Bunting Helen,Georgiadis Dimitris,Chan Antoni,Kollnberger Simon,Bowness Paul
Annals of the rheumatic diseases
OBJECTIVE:Human leucocyte antigen (HLA)-B27 and endoplasmic reticulum aminopeptidase 1 (ERAP1) are strongly associated with ankylosing spondylitis (AS). ERAP1 is a key aminopeptidase in HLA class I presentation and can potentially alter surface expression of HLA-B27 free heavy chains (FHCs). We studied the effects of ERAP1 silencing/inhibition/variations on HLA-B27 FHC expression and Th17 responses in AS. METHODS:Flow cytometry was used to measure surface expression of HLA class I in peripheral blood mononuclear cells (PBMCs) from patients with AS carrying different ERAP1 genotypes (rs2287987, rs30187 and rs27044) and in ERAP1-silenced/inhibited/mutated HLA-B27-expressing antigen presenting cells (APCs). ERAP1-silenced/inhibited APCs were cocultured with KIR3DL2CD3ε-reporter cells or AS CD4+ T cells. Th17 responses of AS CD4+ T cells were measured by interleukin (IL)-17A ELISA and Th17 intracellular cytokine staining. FHC cell surface expression and Th17 responses were also measured in AS PBMCs following ERAP1 inhibition. RESULTS:The AS-protective ERAP1 variants, K528R and Q730E, were associated with reduced surface FHC expression by monocytes from patients with AS and HLA-B27-expressing APCs. ERAP1 silencing or inhibition in APCs downregulated HLA-B27 FHC surface expression, reduced IL-2 production by KIR3DL2CD3ε-reporter cells and suppressed the Th17 expansion and IL-17A secretion by AS CD4+ T cells. ERAP1 inhibition of AS PBMCs reduced HLA class I FHC surface expression by monocytes and B cells, and suppressed Th17 expansion. CONCLUSIONS:ERAP1 activity determines surface expression of HLA-B27 FHCs and potentially promotes Th17 responses in AS through binding of HLA-B27 FHCs to KIR3DL2. Our data suggest that ERAP1 inhibition has potential for AS treatment.
Generation of stable monoclonal antibody-producing B cell receptor-positive human memory B cells by genetic programming.
Kwakkenbos Mark J,Diehl Sean A,Yasuda Etsuko,Bakker Arjen Q,van Geelen Caroline M M,Lukens Michaël V,van Bleek Grada M,Widjojoatmodjo Myra N,Bogers Willy M J M,Mei Henrik,Radbruch Andreas,Scheeren Ferenc A,Spits Hergen,Beaumont Tim
The B cell lymphoma-6 (Bcl-6) and Bcl-xL proteins are expressed in germinal center B cells and enable them to endure the proliferative and mutagenic environment of the germinal center. By introducing these genes into peripheral blood memory B cells and culturing these cells with two factors produced by follicular helper T cells, CD40 ligand (CD40L) and interleukin-21 (IL-21), we convert them to highly proliferating, cell surface B cell receptor (BCR)-positive, immunoglobulin-secreting B cells with features of germinal center B cells, including expression of activation-induced cytidine deaminase (AID). We generated cloned lines of B cells specific for respiratory syncytial virus and used these cells as a source of antibodies that effectively neutralized this virus in vivo. This method provides a new tool to study B cell biology and signal transduction through antigen-specific B cell receptors and for the rapid generation of high-affinity human monoclonal antibodies.
Exercise preconditioning upregulates cerebral integrins and enhances cerebrovascular integrity in ischemic rats.
Ding Y H,Li J,Yao W X,Rafols J A,Clark J C,Ding Y
We hypothesized that exercise preconditioning strengthens brain microvascular integrity against ischemia/reperfusion injury through the tumor necrosis factor (TNF)-integrin signaling pathway. Adult male Sprague Dawley rats (n = 24) were studied in: (1) exercise (the animals run on a treadmill 30 min each day) for 3 weeks, (2) non-exercise. Six animals from each group (n = 12) were subjected to stroke, the remaining animals served as controls (n = 6 x 2). Brain infarction and edema were determined by Nissl staining. Cerebral integrin expression was detected by immunochemistry and stereological methods. In addition, we used flow cytometry to address the causal role of TNF-alpha in inducing the expression of integrins in the human umbilical vein endothelial cells under TNF-alpha or vascular endothelial growth factor (VEGF) pretreatment. Exercise reduces brain infarction and brain edema in stroke. Expressions of integrin subunit alpha(1), alpha(6), beta(1), and beta(4) were increased after exercise. Exercise preconditioning reversed stroke-reduced integrin expression. An in vitro study revealed a causal link between the gradual upregulation of TNF-alpha (rather than VEGF) and cellular expression of integrins. These results demonstrated an increase in cerebral expression of integrins and a decrease in brain injury from stroke after exercise preconditioning. The study suggests that upregulation of integrins during exercise enhances neurovascular integrity after stroke. The changes in integrins might be altered by TNF-alpha.
TIE2-expressing macrophages limit the therapeutic efficacy of the vascular-disrupting agent combretastatin A4 phosphate in mice.
Welford Abigail F,Biziato Daniela,Coffelt Seth B,Nucera Silvia,Fisher Matthew,Pucci Ferdinando,Di Serio Clelia,Naldini Luigi,De Palma Michele,Tozer Gillian M,Lewis Claire E
The Journal of clinical investigation
Vascular-disrupting agents (VDAs) such as combretastatin A4 phosphate (CA4P) selectively disrupt blood vessels in tumors and induce tumor necrosis. However, tumors rapidly repopulate after treatment with such compounds. Here, we show that CA4P-induced vessel narrowing, hypoxia, and hemorrhagic necrosis in murine mammary tumors were accompanied by elevated tumor levels of the chemokine CXCL12 and infiltration by proangiogenic TIE2-expressing macrophages (TEMs). Inhibiting TEM recruitment to CA4P-treated tumors either by interfering pharmacologically with the CXCL12/CXCR4 axis or by genetically depleting TEMs in tumor-bearing mice markedly increased the efficacy of CA4P treatment. These data suggest that TEMs limit VDA-induced tumor injury and represent a potential target for improving the clinical efficacy of VDA-based therapies.
Suppressed monocyte recruitment drives macrophage removal from atherosclerotic plaques of Apoe-/- mice during disease regression.
Potteaux Stephane,Gautier Emmanuel L,Hutchison Susan B,van Rooijen Nico,Rader Daniel J,Thomas Michael J,Sorci-Thomas Mary G,Randolph Gwendalyn J
The Journal of clinical investigation
Experimental models of atherosclerosis suggest that recruitment of monocytes into plaques drives the progression of this chronic inflammatory condition. Cholesterol-lowering therapy leads to plaque stabilization or regression in human atherosclerosis, characterized by reduced macrophage content, but the mechanisms that underlie this reduction are incompletely understood. Mice lacking the gene Apoe (Apoe-/- mice) have high levels of cholesterol and spontaneously develop atherosclerotic lesions. Here, we treated Apoe-/- mice with apoE-encoding adenoviral vectors that induce plaque regression, and investigated whether macrophage removal from plaques during this regression resulted from quantitative alterations in the ability of monocytes to either enter or exit plaques. Within 2 days after apoE complementation, plasma cholesterol was normalized to wild-type levels, and HDL levels were increased 4-fold. Oil red O staining and quantitative mass spectroscopy revealed that esterified cholesterol content was markedly reduced. Plaque macrophage content decreased gradually and was 72% lower than baseline 4 weeks after apoE complementation. Importantly, this reduction in macrophages did not involve migratory egress from plaques or CCR7, a mediator of leukocyte emigration. Instead, marked suppression of monocyte recruitment coupled with a stable rate of apoptosis accounted for loss of plaque macrophages. These data suggest that therapies to inhibit monocyte recruitment to plaques may constitute a more viable strategy to reduce plaque macrophage burden than attempts to promote migratory egress.
ATR and ATM differently regulate WRN to prevent DSBs at stalled replication forks and promote replication fork recovery.
Ammazzalorso Francesca,Pirzio Livia Maria,Bignami Margherita,Franchitto Annapaola,Pichierri Pietro
The EMBO journal
Accurate response to replication arrest is crucial to preserve genome stability and requires both the ATR and ATM functions. The Werner syndrome protein (WRN) is implicated in the recovery of stalled replication forks, and although an ATR/ATM-dependent phosphorylation of WRN was observed after replication arrest, the function of such modifications during the response to perturbed replication is not yet appreciated. Here, we report that WRN is directly phosphorylated by ATR at multiple C-terminal S/TQ residues. Suppression of ATR-mediated phosphorylation of WRN prevents proper accumulation of WRN in nuclear foci, co-localisation with RPA and causes breakage of stalled forks. On the other hand, inhibition of ATM kinase activity or expression of an ATM-unphosphorylable WRN allele leads to retention of WRN in nuclear foci and impaired recruitment of RAD51 recombinase resulting in reduced viability after fork collapse. Altogether, our findings indicate that ATR and ATM promote recovery from perturbed replication by differently regulating WRN at defined moments of the response to replication fork arrest.
Immunization with vaccinia virus induces polyfunctional and phenotypically distinctive CD8(+) T cell responses.
Precopio Melissa L,Betts Michael R,Parrino Janie,Price David A,Gostick Emma,Ambrozak David R,Asher Tedi E,Douek Daniel C,Harari Alexandre,Pantaleo Giuseppe,Bailer Robert,Graham Barney S,Roederer Mario,Koup Richard A
The Journal of experimental medicine
Vaccinia virus immunization provides lifelong protection against smallpox, but the mechanisms of this exquisite protection are unknown. We used polychromatic flow cytometry to characterize the functional and phenotypic profile of CD8(+) T cells induced by vaccinia virus immunization in a comparative vaccine trial of modified vaccinia virus Ankara (MVA) versus Dryvax immunization in which protection was assessed against subsequent Dryvax challenge. Vaccinia virus-specific CD8(+) T cells induced by both MVA and Dryvax were highly polyfunctional; they degranulated and produced interferon gamma, interleukin 2, macrophage inflammatory protein 1beta, and tumor necrosis factor alpha after antigenic stimulation. Responding CD8(+) T cells exhibited an unusual phenotype (CD45RO(-)CD27(intermediate)). The unique phenotype and high degree of polyfunctionality induced by vaccinia virus also extended to inserted HIV gene products of recombinant NYVAC. This quality of the CD8(+) T cell response may be at least partially responsible for the profound efficacy of these vaccines in protection against smallpox and serves as a benchmark against which other vaccines can be evaluated.
CD301b/MGL2 Mononuclear Phagocytes Orchestrate Autoimmune Cardiac Valve Inflammation and Fibrosis.
Meier Lee A,Auger Jennifer L,Engelson Brianna J,Cowan Hannah M,Breed Elise R,Gonzalez-Torres Mayra I,Boyer Joshua D,Verma Mayank,Marath Aubyn,Binstadt Bryce A
BACKGROUND:Valvular heart disease is common and affects the mitral valve (MV) most frequently. Despite the prevalence of MV disease (MVD), the cellular and molecular pathways that initiate and perpetuate it are not well understood. METHODS:K/B.g7 T-cell receptor transgenic mice spontaneously develop systemic autoantibody-associated autoimmunity, leading to fully penetrant fibroinflammatory MVD and arthritis. We used multiparameter flow cytometry, intracellular cytokine staining, and immunofluorescent staining to characterize the cells in inflamed K/B.g7 MVs. We used genetic approaches to study the contribution of mononuclear phagocytes (MNPs) to MVD in this model. Specifically, we generated K/B.g7 mice in which either CX3CR1 or CD301b/macrophage galactose -acetylgalactosamine-specific lectin 2 (MGL2)-expressing MNPs were ablated. Using K/B.g7 mice expressing -Cre, we conditionally deleted critical inflammatory molecules from MNPs, including the Fc-receptor signal-transducing tyrosine kinase Syk and the cell adhesion molecule very late antigen-4. We performed complementary studies using monoclonal antibodies to block key inflammatory molecules. We generated bone marrow chimeric mice to define the origin of the inflammatory cells present in the MV and to determine which valve cells respond to the proinflammatory cytokine tumor necrosis factor (TNF). Finally, we examined specimens from patients with rheumatic heart disease to correlate our findings to human pathology. RESULTS:MNPs comprised the vast majority of MV-infiltrating cells; these MNPs expressed CX3CR1 and CD301b/MGL2. Analogous cells were present in human rheumatic heart disease valves. K/B.g7 mice lacking CX3CR1 or in which CD301b/MGL2-expressing MNPs were ablated were protected from MVD. The valve-infiltrating CD301b/MGL2 MNPs expressed tissue-reparative molecules including arginase-1 and resistin-like molecule α. These MNPs also expressed the proinflammatory cytokines TNF and interleukin-6, and antibody blockade of these cytokines prevented MVD. Deleting Syk from CX3CR1-expressing MNPs reduced their TNF and interleukin-6 production and also prevented MVD. TNF acted through TNF receptor-1 expressed on valve-resident cells to increase the expression of vascular cell adhesion molecule-1. Conditionally deleting the vascular cell adhesion molecule-1 ligand very late antigen-4 from CX3CR1-expressing MNPs prevented MVD. CONCLUSIONS:CD301b/MGL2 MNPs are key drivers of autoimmune MVD in K/B.g7 mice and are also present in human rheumatic heart disease. We define key inflammatory molecules that drive MVD in this model, including Syk, TNF, interleukin-6, very late antigen-4, and vascular cell adhesion molecule-1.
Initial clonal expansion of germinal center B cells takes place at the perimeter of follicles.
Coffey Francis,Alabyev Boris,Manser Tim
Current models of the germinal center (GC) response propose that after stimulation at the edges of T cell zones, pre-GC B cells directly migrate to the center of follicles and proliferate to form GCs. We followed the interrelationship of proliferation, differentiation, and microenvironmental locale in populations of pre-GC B cells responding to antigen. In contrast to the predictions of current models, after accumulation at the T-B interface, these cells appeared at the perimeter of follicles adjacent to the marginal zone. There, they rapidly proliferated for several days but underwent no V gene hypermutation and little heavy-chain class switching. Their chemokine receptor expression pattern indicated that these cells were sessile, yet they had begun to acquire many phenotypic characteristics of GC B cells. The expanded clones were subsequently observed in the center of follicles, suggesting that GCs are created by coalescence of B cells from this follicular perimeter response.
Allergen-induced Changes in Bone Marrow and Airway Dendritic Cells in Subjects with Asthma.
El-Gammal Amani,Oliveria John-Paul,Howie Karen,Watson Richard,Mitchell Patrick,Chen Ruchong,Baatjes Adrian,Smith Steven,Al-Sajee Dhuha,Hawke Thomas J,Killian Kieran J,Gauvreau Gail M,O'Byrne Paul M
American journal of respiratory and critical care medicine
RATIONALE:Dendritic cells (DCs) are antigen-presenting cells essential for the initiation of T-cell responses. Allergen inhalation increases the number of airway DCs and the release of epithelial-derived cytokines, such as IL-33 and thymic stromal lymphopoietin (TSLP), that activate DCs. OBJECTIVES:To examine the effects of inhaled allergen on bone marrow production of DCs and their trafficking into the airways in subjects with allergic asthma, and to examine IL-33 and TSPL receptor expression on DCs. METHODS:Bone marrow, peripheral blood, bronchoalveolar lavage (BAL), and bronchial biopsies were obtained before and after inhalation of diluent and allergen from subjects with asthma that develop allergen-induced dual responses. Classical DCs (cDCs) were cultured from bone marrow CD34(+) cells. cDC1s, cDC2s, and plasmacytoid DCs were measured in bone marrow aspirates, peripheral blood, and BAL by flow cytometry, and cDCs were quantified in bronchial biopsies by immunofluorescence staining. MEASUREMENTS AND MAIN RESULTS:Inhaled allergen increased the number of cDCs grown from bone marrow progenitors, and cDCs and plasmacytoid DCs in bone marrow aspirates 24 hours after allergen. Allergen also increased the expression of the TSLP receptor, but not the IL-33 receptor, on bone marrow DCs. Finally, inhaled allergen increased the percentage of cDC1s and cDC2s in BAL but only cDC2s in bronchial tissues. CONCLUSIONS:Inhaled allergen increases DCs in bone marrow and trafficking of DCs into the airway, which is associated with the development airway inflammation in subjects with allergic asthma. Inhaled allergen challenge also increases expression of TSLP, but not IL-33, receptors on bone marrow DCs.
Differential effect of methotrexate on the increased CCR2 density on circulating CD4 T lymphocytes and monocytes in active chronic rheumatoid arthritis, with a down regulation only on monocytes in responders.
Ellingsen T,Hornung N,Møller B K,Poulsen J H,Stengaard-Pedersen K
Annals of the rheumatic diseases
OBJECTIVES:To evaluate the effect of orally administered methotrexate (MTX) on the density of CC chemokine receptor 2 (CCR2) and CXC chemokine receptor 3 (CXCR3) on circulating monocytes, and the coexpression of CXCR3 and CCR2 on CD4 T lymphocytes in patients with active chronic rheumatoid arthritis. METHODS:All 34 patients with rheumatoid arthritis fulfilled the 1987 American Rheumatism Association criteria and were followed for 16 weeks after starting MTX. Peripheral blood mononuclear cells were analysed for CCR2 and CXCR3 density by three-colour flow cytometry before initiation of MTX and at week 12. RESULTS:22 (65%) patients were non-responders, 12 (35%) patients responded to MTX by American College of Rheumatology (ACR)20% criteria, and 8 (24%) of these patients responded by ACR50%. In patients with active rheumatoid arthritis before starting MTX, CCR2 density on circulating monocytes, CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes was increased compared with controls. During 12 weeks of MTX treatment, the CCR2 density on monocytes decreased significantly in the ACR50% group but not in the ACR20% and non-responder groups. The increased CCR2 density on CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes was unaffected by the reduction in disease activity measured in relation to MTX treatment. The percentage of both monocytes and CD4(+) CXCR3(+) and CD4+ CXCR3(-) T lymphocytes among the peripheral circulating mononuclear cells did not change during MTX treatment. CONCLUSIONS:Active chronic rheumatoid arthritis is characterised by enhanced CCR2 density on circulating monocytes and CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes. During MTX treatment, a decrease in CCR2 density on monocytes in the ACR50% responder group was associated with decreased disease activity. The increased CCR2 density on CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes was uninfluenced by MTX and disease activity.
Th17 cells play a critical role in the development of experimental Sjögren's syndrome.
Lin Xiang,Rui Ke,Deng Jun,Tian Jie,Wang Xiaohui,Wang Shengjun,Ko King-Hung,Jiao Zhijun,Chan Vera Sau-Fong,Lau Chak Sing,Cao Xuetao,Lu Liwei
Annals of the rheumatic diseases
OBJECTIVE:Although Th17 cells have been increasingly recognised as an important effector in various autoimmune diseases, their function in the pathogenesis of Sjögren's syndrome (SS) remains largely uncharacterised. This study aims to determine the role of Th17 cells in the development of experimental SS (ESS). METHODS:The ESS was induced in wildtype and IL-17A knockout (IL-17 KO) C57BL/6 mice immunised with salivary glands (SG) proteins. Phenotypic analysis of immune cells in the draining cervical lymph nodes (CLN) and SG was performed by flow cytometry and immunofluorescence microscopy. To determine the role of Th17 cells in ESS, immunised IL-17 KO mice were adoptively transferred with in vitro-generated Th17 cells and monitored for SS development. The salivary flow rate was measured, whereas inflammatory infiltration and tissue destruction in SG were assessed by histopathology. RESULTS:SG protein-immunised mice developed overt SS symptoms with increased Th17 cells detected in CLN and within lymphocytic foci in inflamed SG. Notably, immunised IL-17 KO mice were completely resistant for SS induction, showing no evidence of disease symptoms and histopathological changes in SG. Adoptive transfer of Th17 cells rapidly induced the onset of ESS in immunised IL-17 KO mice with markedly reduced saliva secretion, elevated autoantibody production and pronounced inflammation and tissue damage in SG. CONCLUSIONS:Our findings have defined a critical role of Th17 cells in the pathogenesis of ESS. Further studies may validate Th17 cell as a potential target for treating SS.
Inhaled vasoactive intestinal peptide exerts immunoregulatory effects in sarcoidosis.
Prasse Antje,Zissel Gernot,Lützen Niklas,Schupp Jonas,Schmiedlin Rene,Gonzalez-Rey Elena,Rensing-Ehl Anne,Bacher Gerald,Cavalli Vera,Bevec Dorian,Delgado Mario,Müller-Quernheim Joachim
American journal of respiratory and critical care medicine
RATIONALE:Previous studies suggest an important immunoregulatory role of vasoactive intestinal peptide (VIP) in experimental models of chronic noninfectious inflammation. Sarcoidosis is characterized by noncaseating epitheloid cell granulomas, where excessive tumor necrosis factor-alpha production by pulmonary macrophages plays a critical role in granuloma formation and disease progression, which may lead to fatal organ dysfunction. OBJECTIVES:To test whether inhaled VIP has an immunoregulatory role. Sarcoid alveolitis was used as a prototype of immune-mediated chronic lung inflammation. METHODS:In an open clinical phase II study, we treated 20 patients with histologically proved sarcoidosis and active disease with nebulized VIP for 4 weeks. MEASUREMENTS AND MAIN RESULTS:VIP inhalation was safe, well-tolerated, and significantly reduced the production of tumor necrosis factor-alpha by cells isolated from bronchoalveolar lavage fluids of these patients. VIP treatment significantly increased the numbers of bronchoalveolar lavage CD4(+)CD127(-)CD25(+) T cells, which showed regulatory activities on conventional effector T cells. In vitro experiments demonstrated the capacity of VIP to convert naive CD4(+)CD25(-) T cells into CD4(+)CD25(+)FoxP3(+) regulatory T cells, suggesting the generation of peripheral regulatory T cells by VIP treatment. CONCLUSIONS:This study is the first to show the immunoregulatory effect of VIP in humans, and supports the notion of inhaled VIP as an attractive future therapy to dampen exaggerated immune responses in lung disorders. Thus, the inhalation of neuropeptides may be developed into a new therapeutic principle for chronic inflammatory lung disorders in humans.
Eosinophils express muscarinic receptors and corticotropin-releasing factor to disrupt the mucosal barrier in ulcerative colitis.
Wallon Conny,Persborn Mats,Jönsson Maria,Wang Arthur,Phan Van,Lampinen Maria,Vicario Maria,Santos Javier,Sherman Philip M,Carlson Marie,Ericson Ann-Charlott,McKay Derek M,Söderholm Johan D
BACKGROUND & AIMS:Altered intestinal barrier function has been implicated in the pathophysiology of ulcerative colitis (UC) in genetic, functional, and epidemiological studies. Mast cells and corticotropin-releasing factor (CRF) regulate the mucosal barrier in human colon. Because eosinophils are often increased in colon tissues of patients with UC, we assessed interactions among mast cells, CRF, and eosinophils in the mucosal barrier of these patients. METHODS:Transmucosal fluxes of protein antigens (horseradish peroxidase) and paracellular markers ((51)Cr-EDTA, fluorescein isothiocyanate-dextran 4000) were studied in noninflamed, colonic mucosal biopsy samples collected from 26 patients with UC and 53 healthy volunteers (controls); samples were mounted in Ussing chambers. We also performed fluorescence and electron microscopy of human tissue samples, assessed isolated eosinophils, and performed mechanistic studies using in vitro cocultured eosinophils (15HL-60), mast cells (HMC-1), and a colonic epithelial cell line (T84). RESULTS:Colon tissues from patients with UC had significant increases in permeability to protein antigens compared with controls. Permeability was blocked by atropine (a muscarinic receptor antagonist), α-helical CRF(9-41) (a CRF receptor antagonist), and lodoxamide (a mast-cell stabilizer). Eosinophils were increased in number in UC tissues (compared with controls), expressed the most M2 and M3 muscarinic receptors of any mucosal cell type, and had immunoreactivity to CRF. In coculture studies, carbachol activation of eosinophils caused production of CRF and activation of mast cells, which increased permeability of T84 epithelial cells to macromolecules. CONCLUSIONS:We identified a neuroimmune intercellular circuit (from cholinergic nerves, via eosinophils to mast cells) that mediates colonic mucosal barrier dysfunction in patients with UC. This circuit might exacerbate mucosal inflammation.
Stepwise activation of enhancer and promoter regions of the B cell commitment gene Pax5 in early lymphopoiesis.
Decker Thorsten,Pasca di Magliano Marina,McManus Shane,Sun Qiong,Bonifer Constanze,Tagoh Hiromi,Busslinger Meinrad
Pax5 is an essential regulator of B cell identity and function. Here, we used transgenesis and deletion mapping to identify a potent enhancer in intron 5 of the Pax5 locus. This enhancer in combination with the promoter region was sufficient to recapitulate the B lymphoid expression of Pax5. The enhancer was silenced by DNA methylation in embryonic stem cells, but became activated in multipotent hematopoietic progenitors. It contained functional binding sites for the transcription factors PU.1, IRF4, IRF8, and NF-kappaB, suggesting that these regulators contribute to sequential enhancer activation in hematopoietic progenitors and during B cell development. In contrast, the promoter region was repressed by Polycomb group proteins in non-B cells and was activated only at the onset of pro-B cell development through induction of chromatin remodeling by the transcription factor EBF1. These experiments demonstrate a stepwise activation of Pax5 in early lymphopoiesis and provide mechanistic insights into the process of B cell commitment.
Lyn kinase controls basophil GATA-3 transcription factor expression and induction of Th2 cell differentiation.
Charles Nicolas,Watford Wendy T,Ramos Haydeé L,Hellman Lars,Oettgen Hans C,Gomez Gregorio,Ryan John J,O'Shea John J,Rivera Juan
T helper 1 (Th1)-Th2 cell balance is key to host defense and its dysregulation has pathophysiological consequences. Basophils are important in Th2 cell differentiation. However, the factors controlling the onset and extent of basophil-mediated Th2 cell differentiation are unknown. Here, we demonstrate that Lyn kinase dampened basophil expression of the transcription factor GATA-3 and the initiation and extent of Th2 cell differentiation. Lyn-deficient mice had a marked basophilia, a constitutive Th2 cell skewing that was exacerbated upon in vivo challenge of basophils, produced antibodies to a normally inert antigen, and failed to appropriately respond to a Th1 cell-inducing pathogen. The Th2 cell skewing was dependent on basophils, immunoglobulin E, and interleukin-4, but was independent of mast cells. Our findings demonstrate that basophil-expressed Lyn kinase exerts regulatory control on Th2 cell differentiation and function.
Cloning of a representative genomic library of the human X chromosome after sorting by flow cytometry.
Davies K E,Young B D,Elles R G,Hill M E,Williamson R
A library of 50,000 recombinants representative of the human X chromosome has been constructed. Human X chromosomes were physically separated using a fluorescence-activated cell sorter. The DNA was purified from the chromosomes, digested to completion with the restriction enzyme EcoRI and cloned into the phage lambda gtWES.lambda B. The X-derived nature of the recombinants was confirmed by hybridization to rodent/human cell line DNA containing only the human X chromosome. Such libraries will be particularly useful for the investigation of genetic diseases such as Duchenne muscular dystrophy, where the basic defect has not been elucidated, and of neoplasia, where several specific chromosomal anomalies, particularly for the leukaemias, have been identified.
Targeting of Cancer Cells Using Quantum Dot-Polypeptide Hybrid Assemblies that Function as Molecular Imaging Agents and Carrier Systems.
Atmaja Bayu,Lui Bertrand H,Hu Yuhua,Beck Stayce E,Frank Curtis W,Cochran Jennifer R
Advanced functional materials
We report a highly tunable quantum dot (QD)-polypeptide hybrid assembly system with potential uses for both molecular imaging and delivery of biomolecular cargo to cancer cells. In this work, we demonstrate the tunability of the assembly system, its application for imaging cancer cells, and its ability to carry a biomolecule. The assemblies are formed through the self-assembly of carboxyl-functionalized QDs and poly(diethylene glycol-L-lysine)-poly(L-lysine) (PEGLL-PLL) diblock copolypeptide molecules, and they are modified with peptide ligands containing a cyclic arginine-glycine-aspartate [c(RGD)] motif that has affinity for αβ and αβ integrins overexpressed on the tumor vasculature. To illustrate the tunability of the QD-polypeptide assembly system, we show that binding to U87MG glioblastoma cells can be modulated and optimized by changing either the conditions under which the assemblies are formed or the relative lengths of the PEGLL and PLL blocks in the PEGLL-PLL molecules. The optimized c(RGD)-modified assemblies bind integrin receptors on U87MG cells and are endocytosed, as demonstrated by flow cytometry and live-cell imaging. Binding specificity is confirmed by competition with an excess of free c(RGD) peptide. Finally, we show that the QD-polypeptide assemblies can be loaded with fluorescently labeled ovalbumin, as a proof-of-concept for their potential use in biomolecule delivery.
Regulation of lymphoid versus myeloid fate 'choice' by the transcription factor Mef2c.
Stehling-Sun Sandra,Dade Jessica,Nutt Stephen L,DeKoter Rodney P,Camargo Fernando D
Despite advances in the identification of lymphoid-restricted progenitor cells, the transcription factors essential for their generation remain to be identified. Here we describe an unexpected function for the myeloid oncogene product Mef2c in lymphoid development. Mef2c deficiency was associated with profound defects in the production of B cells, T cells, natural killer cells and common lymphoid progenitor cells and an enhanced myeloid output. In multipotent progenitors, Mef2c was required for the proper expression of several key lymphoid regulators and restriction of the myeloid fate. Our studies also show that Mef2c was a critical transcriptional target of the transcription factor PU.1 during lymphopoiesis. Thus, Mef2c is a crucial component of the transcriptional network that regulates cell fate 'choice' in multipotent progenitors.
Epigenetic Dysregulation of the Dynamin-Related Protein 1 Binding Partners MiD49 and MiD51 Increases Mitotic Mitochondrial Fission and Promotes Pulmonary Arterial Hypertension: Mechanistic and Therapeutic Implications.
Chen Kuang-Hueih,Dasgupta Asish,Lin Jianhui,Potus François,Bonnet Sébastien,Iremonger James,Fu Jennifer,Mewburn Jeffrey,Wu Danchen,Dunham-Snary Kimberly,Theilmann Anne L,Jing Zhi-Cheng,Hindmarch Charles,Ormiston Mark L,Lawrie Allan,Archer Stephen L
BACKGROUND:Mitotic fission is increased in pulmonary arterial hypertension (PAH), a hyperproliferative, apoptosis-resistant disease. The fission mediator dynamin-related protein 1 (Drp1) must complex with adaptor proteins to cause fission. Drp1-induced fission has been therapeutically targeted in experimental PAH. Here, we examine the role of 2 recently discovered, poorly understood Drp1 adapter proteins, mitochondrial dynamics protein of 49 and 51 kDa (MiD49 and MiD51), in normal vascular cells and explore their dysregulation in PAH. METHODS:Immunoblots of pulmonary artery smooth muscle cells (control, n=6; PAH, n=8) and immunohistochemistry of lung sections (control, n=6; PAH, n=6) were used to assess the expression of MiD49 and MiD51. The effects of manipulating MiDs on cell proliferation, cell cycle, and apoptosis were assessed in human and rodent PAH pulmonary artery smooth muscle cells with flow cytometry. Mitochondrial fission was studied by confocal imaging. A microRNA (miR) involved in the regulation of MiD expression was identified using microarray techniques and in silico analyses. The expression of circulatory miR was assessed with quantitative reverse transcription-polymerase chain reaction in healthy volunteers (HVs) versus patients with PAH from Sheffield, UK (plasma: HV, n=29, PAH, n=27; whole blood: HV, n=11, PAH, n=14) and then confirmed in a cohort from Beijing, China (plasma: HV, n=19, PAH, n=36; whole blood: HV, n=20, PAH, n=39). This work was replicated in monocrotaline and Sugen 5416-hypoxia, preclinical PAH models. Small interfering RNAs targeting MiDs or an miR mimic were nebulized to rats with monocrotaline-induced PAH (n=4-10). RESULTS:MiD expression is increased in PAH pulmonary artery smooth muscle cells, which accelerates Drp1-mediated mitotic fission, increases cell proliferation, and decreases apoptosis. Silencing MiDs (but not other Drp1 binding partners, fission 1 or mitochondrial fission factor) promotes mitochondrial fusion and causes G1-phase cell cycle arrest through extracellular signal-regulated kinases 1/2- and cyclin-dependent kinase 4-dependent mechanisms. Augmenting MiDs in normal cells causes fission and recapitulates the PAH phenotype. MiD upregulation results from decreased miR-34a-3p expression. Circulatory miR-34a-3p expression is decreased in both patients with PAH and preclinical models of PAH. Silencing MiDs or augmenting miR-34a-3p regresses experimental PAH. CONCLUSIONS:In health, MiDs regulate Drp1-mediated fission, whereas in disease, epigenetic upregulation of MiDs increases mitotic fission, which drives pathological proliferation and apoptosis resistance. The miR-34a-3p-MiD pathway offers new therapeutic targets for PAH.
Cardioprotective Role of Myeloid-Derived Suppressor Cells in Heart Failure.
Zhou Ling,Miao Kun,Yin Bingjiao,Li Huaping,Fan Jiahui,Zhu Yazhen,Ba Hongping,Zhang Zunyue,Chen Fang,Wang Jing,Zhao Chunxia,Li Zhuoya,Wang Dao Wen
BACKGROUND:Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of cells that expand in cancer, inflammation, and infection and negatively regulate inflammation and the immune response. Heart failure (HF) is a complex clinical syndrome wherein inflammation induction and incomplete resolution can potentially contribute to HF development and progression. However, the role of MDSCs in HF remains unclear. METHODS:The percentage of MDSCs in patients with HF and in mice with pressure overload-induced HF using isoproterenol infusion or transverse aortic constriction (TAC) was detected by flow cytometry. The effects of MDSCs on isoproterenol- or TAC-induced HF were observed on depleting MDSCs with 5-fluorouracil (50 mg/kg) or gemcitabine (120 mg/kg), transferring purified MDSCs, or enhancing endogenous MDSCs with rapamycin (2 mg·kg·d). Hypertrophic markers and inflammatory factors were detected by ELISA, real-time polymerase chain reaction, or Western blot. Cardiac functions were determined by echocardiography and hemodynamic analysis. RESULTS:The percentage of human leukocyte antigen-D-related (HLA-DR)CD33CD11b MDSCs in the blood of patients with HF was significantly increased and positively correlated with disease severity and increased plasma levels of cytokines, including interleukin-6, interleukin-10, and transforming growth factor-β. Furthermore, MDSCs derived from patients with HF inhibited T-cell proliferation and interferon-γ secretion. Similar results were observed in TAC- and isoproterenol-induced HF in mice. Pharmaceutical depletion of MDSCs significantly exacerbated isoproterenol- and TAC-induced pathological cardiac remodeling and inflammation, whereas adoptive transfer of MDSCs prominently rescued isoproterenol- and TAC-induced HF. Consistently, administration of rapamycin significantly increased endogenous MDSCs by suppressing their differentiation and improved isoproterenol- and TAC-induced HF, but MDSC depletion mostly blocked beneficial rapamycin-mediated effects. Mechanistically, MDSC-secreted molecules suppressed isoproterenol-induced hypertrophy and proinflammatory gene expression in cardiomyocytes in a coculture system. Neutralization of interleukin-10 blunted both monocytic MDSC- and granulocytic MDSC-mediated anti-inflammatory and antihypertrophic effects, but treatment with a nitric oxide inhibitor only partially blocked the antihypertrophic effect of monocytic MDSCs. CONCLUSIONS:Our findings revealed a cardioprotective role of MDSCs in HF by their antihypertrophic effects on cardiomyocytes and anti-inflammatory effects through interleukin-10 and nitric oxide. Pharmacological targeting of MDSCs by rapamycin constitutes a promising therapeutic strategy for HF.
Circulation of CD34+ progenitor cell populations in patients with idiopathic dilated and ischaemic cardiomyopathy (DCM and ICM).
Theiss Hans D,David Robert,Engelmann Markus G,Barth Andreas,Schotten Klaus,Naebauer Michael,Reichart Bruno,Steinbeck Gerhard,Franz Wolfgang-M
European heart journal
AIMS:This study aimed at analysing the endogenous stem cell circulation in patients suffering from idiopathic dilated cardiomyopathy (DCM) and ischaemic cardiomyopathy (ICM). METHODS AND RESULTS:Cytokines in peripheral blood were analysed using enzyme-linked immunosorbent assay and circulating CD34(+) stem cell populations (CD34(+)CD133(+), CD34(+)CD31(+), CD34(+)CXCR-4(+)) were measured by flow cytometry in DCM patients (n = 25), ICM patients (n = 15), and controls (n = 10). Explanted DCM (n = 5), ICM (n = 4) and normal hearts (n = 5) were analysed for the expression of several homing factors [stromal cell-derived factor-1 (SDF-1), Stem cell factor (SCF), HIF-1a, vascular cell adhesion molecule (VCAM), and Hepatocyte growth factor] by quantitative real-time polymerase chain reaction (PCR). SDF-1 was significantly elevated and positively correlated with brain natriuretic peptide (BNP) in peripheral blood of DCM and ICM patients showing the same New York heart association- (NYHA) class. In DCM patients circulating CD34(+) cell populations were significantly increased in comparison to ICM patients and controls. mRNA of SDF-1, SCF, HIF-1a, and VCAM related to glyceraldehyde-3-phosphate dehydrogenase was significantly upregulated in ICM hearts when compared with DCM hearts and controls. CONCLUSION:Myocardial homing factors are upregulated in ICM when compared with DCM hearts. Reduced homing of stem cells might therefore explain the increased number of CD34(+) cells in DCM patients. These findings may open a new insight into the pathology and the treatment of idiopathic DCM.
Antibodies Against Immune Checkpoint Molecules Restore Functions of Tumor-Infiltrating T Cells in Hepatocellular Carcinomas.
Zhou Guoying,Sprengers Dave,Boor Patrick P C,Doukas Michail,Schutz Hannah,Mancham Shanta,Pedroza-Gonzalez Alexander,Polak Wojciech G,de Jonge Jeroen,Gaspersz Marcia,Dong Haidong,Thielemans Kris,Pan Qiuwei,IJzermans Jan N M,Bruno Marco J,Kwekkeboom Jaap
BACKGROUND & AIMS:Ligand binding to inhibitory receptors on immune cells, such as programmed cell death 1 (PD-1) and cytotoxic T-lymphocyte associated protein 4 (CTLA4), down-regulates the T-cell-mediated immune response (called immune checkpoints). Antibodies that block these receptors increase antitumor immunity in patients with melanoma, non-small-cell lung cancer, and renal cell cancer. Tumor-infiltrating CD4 and CD8 T cells in patients with hepatocellular carcinoma (HCC) have been found to be functionally compromised. We analyzed HCC samples from patients to determine if these inhibitory pathways prevent T-cell responses in HCCs and to find ways to restore their antitumor functions. METHODS:We collected HCC samples from 59 patients who underwent surgical resection from November 2013 through May 2017, along with tumor-free liver tissues (control tissues) and peripheral blood samples. We isolated tumor-infiltrating lymphocytes (TIL) and intra-hepatic lymphocytes. We used flow cytometry to quantify expression of the inhibitory receptors PD-1, hepatitis A virus cellular receptor 2 (TIM3), lymphocyte activating 3 (LAG3), and CTLA4 on CD8 and CD4 T cells from tumor, control tissue, and blood; we studied the effects of antibodies that block these pathways in T-cell activation assays. RESULTS:Expression of PD-1, TIM3, LAG3, and CTLA4 was significantly higher on CD8 and CD4 T cells isolated from HCC tissue than control tissue or blood. Dendritic cells, monocytes, and B cells in HCC tumors expressed ligands for these receptors. Expression of PD-1, TIM3, and LAG3 was higher on tumor-associated antigen (TAA)-specific CD8 TIL, compared with other CD8 TIL. Compared with TIL that did not express these inhibitory receptors, CD8 and CD4 TIL that did express these receptors had higher levels of markers of activation, but similar or decreased levels of granzyme B and effector cytokines. Antibodies against CD274 (PD-ligand1 [PD-L1]), TIM3, or LAG3 increased proliferation of CD8 and CD4 TIL and cytokine production in response to stimulation with polyclonal antigens or TAA. Importantly, combining antibody against PD-L1 with antibodies against TIM3, LAG3, or CTLA4 further increased TIL functions. CONCLUSIONS:The immune checkpoint inhibitory molecules PD-1, TIM3, and LAG3 are up-regulated on TAA-specific T cells isolated from human HCC tissues, compared with T cells from tumor-free liver tissues or blood. Antibodies against PD-L1, TIM3, or LAG3 restore responses of HCC-derived T cells to tumor antigens, and combinations of the antibodies have additive effects. Strategies to block PD-L1, TIM3, and LAG3 might be developed for treatment of primary liver cancer.