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    Nanomorphological and mechanical reconstruction of mesenchymal stem cells during early apoptosis detected by atomic force microscopy. Su Xuelian,Zhou Haijing,Bao Guangjie,Wang Jizeng,Liu Lin,Zheng Qian,Guo Manli,Zhang Jinting Biology open Stem cell apoptosis exists widely in embryonic development, tissue regeneration, repair, aging and pathophysiology of disease. The molecular mechanism of stem cell apoptosis has been extensively investigated. However, alterations in biomechanics and nanomorphology have rarely been studied. Therefore, an apoptosis model was established for bone marrow mesenchymal stem cells (BMSCs) and the reconstruction of the mechanical properties and nanomorphology of the cells were investigated in detail. Atomic force microscopy (AFM), scanning electron microscopy (SEM), laser scanning confocal microscopy (LSCM), flow cytometry and Cell Counting Kit-8 analysis were applied to assess the cellular elasticity modulus, geometry, nanomorphology, cell surface ultrastructure, biological viability and early apoptotic signals (phosphatidylserine, PS). The results indicated that the cellular elastic modulus and volume significantly decreased, whereas the cell surface roughness obviously increased during the first 3 h of cytochalasin B (CB) treatment. Moreover, these alterations preceded the exposure of biological apoptotic signal PS. These findings suggested that cellular mechanical damage is connected with the apoptosis of BMSCs, and the alterations in mechanics and nanomorphology may be a sensitive index to detect alterations in cell viability during apoptosis. The results contribute to further understanding of apoptosis from the perspective of cell mechanics. 10.1242/bio.048108
    Functional variations between Mesenchymal Stem Cells of different tissue origins: A comparative gene expression profiling. Sangeetha K N,Vennila Rosy,Secunda R,Sakthivel S,Pathak Surajit,Jeswanth S,Surendran R Biotechnology letters BACKGROUND:Mesenchymal Stem Cells (MSCs), regardless of the tissue sources, are considered as excellent candidates for cellular therapy as they are immune-privileged cells containing a multitude of therapeutic functions that aid in tissue regeneration and repair. For the effective application of these cells in cell therapy, it is important to understand and characterize their biological functions. OBJECTIVES:The present study attempts to characterize the variations in multipotent function such as cell surface antigen levels, proliferation, differentiation and stemness (pluripotency) potential of MSCs isolated from foetal [wharton's jelly (WJ), foetal and maternal side of placenta (PF and PM)] and adult tissue sources [bone marrow (BM) and adipose tissue (AT)] using gene expression by real time PCR (qRT-PCR). RESULTS:Amongst the different tissue sources, PM, PF and AT-MSCs exhibited significant increase (p < 0.001, p < 0.001 and p < 0.01 respectively) in CD 73 expression and therefore could have a role in immunomodulation. WJ-MSCs exhibited superior proliferation potential based on growth curve, PCNA and Wnt gene expression. BM-MSCs were superior in exhibiting trilineage differentiation. Enhanced stemness potential (Oct 4 and Nanog) was observed for both BM and WJ-MSCs. In addition, BM and WJ-MSCs expressed high levels of CD 90 making them suitable in bone repair and regeneration. CONCLUSION:Thus to conclude, out of the five different sources tested, BM an adult source and WJ-MSCs a foetal source were superior in exhibiting most of the biological functions indicating that these sources may be suitable candidates for cell repair and regeneration studies. 10.1007/s10529-020-02898-x
    Pericytes of Multiple Organs Do Not Behave as Mesenchymal Stem Cells In Vivo. Guimarães-Camboa Nuno,Cattaneo Paola,Sun Yunfu,Moore-Morris Thomas,Gu Yusu,Dalton Nancy D,Rockenstein Edward,Masliah Eliezer,Peterson Kirk L,Stallcup William B,Chen Ju,Evans Sylvia M Cell stem cell Pericytes are widely believed to function as mesenchymal stem cells (MSCs), multipotent tissue-resident progenitors with great potential for regenerative medicine. Cultured pericytes isolated from distinct tissues can differentiate into multiple cell types in vitro or following transplantation in vivo. However, the cell fate plasticity of endogenous pericytes in vivo remains unclear. Here, we show that the transcription factor Tbx18 selectively marks pericytes and vascular smooth muscle cells in multiple organs of adult mouse. Fluorescence-activated cell sorting (FACS)-purified Tbx18-expressing cells behaved as MSCs in vitro. However, lineage-tracing experiments using an inducible Tbx18-CreERT2 line revealed that pericytes and vascular smooth muscle cells maintained their identity in aging and diverse pathological settings and did not significantly contribute to other cell lineages. These results challenge the current view of endogenous pericytes as multipotent tissue-resident progenitors and suggest that the plasticity observed in vitro or following transplantation in vivo arises from artificial cell manipulations ex vivo. 10.1016/j.stem.2016.12.006
    Cord-blood engraftment with ex vivo mesenchymal-cell coculture. de Lima Marcos,McNiece Ian,Robinson Simon N,Munsell Mark,Eapen Mary,Horowitz Mary,Alousi Amin,Saliba Rima,McMannis John D,Kaur Indreshpal,Kebriaei Partow,Parmar Simrit,Popat Uday,Hosing Chitra,Champlin Richard,Bollard Catherine,Molldrem Jeffrey J,Jones Roy B,Nieto Yago,Andersson Borje S,Shah Nina,Oran Betul,Cooper Laurence J N,Worth Laura,Qazilbash Muzaffar H,Korbling Martin,Rondon Gabriela,Ciurea Stefan,Bosque Doyle,Maewal Ila,Simmons Paul J,Shpall Elizabeth J The New England journal of medicine BACKGROUND:Poor engraftment due to low cell doses restricts the usefulness of umbilical-cord-blood transplantation. We hypothesized that engraftment would be improved by transplanting cord blood that was expanded ex vivo with mesenchymal stromal cells. METHODS:We studied engraftment results in 31 adults with hematologic cancers who received transplants of 2 cord-blood units, 1 of which contained cord blood that was expanded ex vivo in cocultures with allogeneic mesenchymal stromal cells. The results in these patients were compared with those in 80 historical controls who received 2 units of unmanipulated cord blood. RESULTS:Coculture with mesenchymal stromal cells led to an expansion of total nucleated cells by a median factor of 12.2 and of CD34+ cells by a median factor of 30.1. With transplantation of 1 unit each of expanded and unmanipulated cord blood, patients received a median of 8.34×10(7) total nucleated cells per kilogram of body weight and 1.81×10(6) CD34+ cells per kilogram--doses higher than in our previous transplantations of 2 units of unmanipulated cord blood. In patients in whom engraftment occurred, the median time to neutrophil engraftment was 15 days in the recipients of expanded cord blood, as compared with 24 days in controls who received unmanipulated cord blood only (P<0.001); the median time to platelet engraftment was 42 days and 49 days, respectively (P=0.03). On day 26, the cumulative incidence of neutrophil engraftment was 88% with expansion versus 53% without expansion (P<0.001); on day 60, the cumulative incidence of platelet engraftment was 71% and 31%, respectively (P<0.001). CONCLUSIONS:Transplantation of cord-blood cells expanded with mesenchymal stromal cells appeared to be safe and effective. Expanded cord blood in combination with unmanipulated cord blood significantly improved engraftment, as compared with unmanipulated cord blood only. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT00498316.). 10.1056/NEJMoa1207285
    Mesenchymal stem cell treatment improves outcome of COVID-19 patients via multiple immunomodulatory mechanisms. Cell research The infusion of coronavirus disease 2019 (COVID-19) patients with mesenchymal stem cells (MSCs) potentially improves clinical symptoms, but the underlying mechanism remains unclear. We conducted a randomized, single-blind, placebo-controlled (29 patients/group) phase II clinical trial to validate previous findings and explore the potential mechanisms. Patients treated with umbilical cord-derived MSCs exhibited a shorter hospital stay (P = 0.0198) and less time required for symptoms remission (P = 0.0194) than those who received placebo. Based on chest images, both severe and critical patients treated with MSCs showed improvement by day 7 (P = 0.0099) and day 21 (P = 0.0084). MSC-treated patients had fewer adverse events. MSC infusion reduced the levels of C-reactive protein, proinflammatory cytokines, and neutrophil extracellular traps (NETs) and promoted the maintenance of SARS-CoV-2-specific antibodies. To explore how MSCs modulate the immune system, we employed single-cell RNA sequencing analysis on peripheral blood. Our analysis identified a novel subpopulation of VNN2 hematopoietic stem/progenitor-like (HSPC-like) cells expressing CSF3R and PTPRE that were mobilized following MSC infusion. Genes encoding chemotaxis factors - CX3CR1 and L-selectin - were upregulated in various immune cells. MSC treatment also regulated B cell subsets and increased the expression of costimulatory CD28 in T cells in vivo and in vitro. In addition, an in vivo mouse study confirmed that MSCs suppressed NET release and reduced venous thrombosis by upregulating kindlin-3 signaling. Together, our results underscore the role of MSCs in improving COVID-19 patient outcomes via maintenance of immune homeostasis. 10.1038/s41422-021-00573-y
    Milk Fat Globule-EGF Factor 8, Secreted by Mesenchymal Stem Cells, Protects Against Liver Fibrosis in Mice. An Su Yeon,Jang Yu Jin,Lim Hee-Joung,Han Jiyou,Lee Jaehun,Lee Gyunggyu,Park Ji Young,Park Seo-Young,Kim Ji Hyang,Do Byung-Rok,Han Choongseong,Park Hee-Kyung,Kim Ok-Hee,Song Myeong Jun,Kim Say-June,Kim Jong-Hoon Gastroenterology BACKGROUND & AIMS:Mesenchymal stem cells (MSCs) mediate tissue repair and might be used to prevent or reduce liver fibrosis. However, little is known about the anti-fibrotic factors secreted from MSCs or their mechanisms. METHODS:Umbilical cord-derived MSCs (UCMSCs) were differentiated into hepatocyte-like cells (hpUCMSCs), medium was collected, and secretome proteins were identified and quantified using nanochip-liquid chromatography/quadrupole time-of-flight mass spectrometry. Liver fibrosis was induced in mice by intraperitoneal injection of thioacetamide or CCl; some mice were then given injections of secretomes or proteins. Liver tissues were collected and analyzed by histology or polymerase chain reaction array to analyze changes in gene expression patterns. We analyzed the effects of MSC secretomes and potential anti-fibrotic proteins on transforming growth factor β 1 (TGFβ1)-mediated activation of human hepatic stellate cell (HSC) lines (hTert-HSC and LX2) and human primary HSCs. Liver tissues were collected from 16 patients with liver cirrhosis and 16 individuals without cirrhosis (controls) in Korea and analyzed by immunohistochemistry and immunoblots. RESULTS:In mice with fibrosis, accumulation of extracellular matrix proteins was significantly reduced 3 days after injecting secretomes from UCMSCs, and to a greater extent from hpUCMSCs; numbers of activated HSCs that expressed the myogenic marker α-smooth muscle actin (α-SMA, encoded by ACTA2 [actin, alpha 2, smooth muscle]) were also reduced. Secretomes from UCMSCs, and to a greater extent from hpUCMSCs, reduced liver expression of multiple fibrotic factors, collagens, metalloproteinases, TGFβ, and Smad proteins in the TGFβ signaling pathways. In HSC cell lines and primary HSCs, TGFβ1-stimulated upregulation of α-SMA was significantly inhibited (and SMAD2 phosphorylation reduced) by secretomes from UCMSCs, and to a greater extent from hpUCMSCs. We identified 32 proteins in secretomes of UCMSCs that were more highly concentrated in secretomes from hpUCMSCs and inhibited TGFβ-mediated activation of HSCs. One of these, milk fat globule-EGF factor 8 (MFGE8), was a strong inhibitor of activation of human primary HSCs. We found MFGE8 to down-regulate expression of TGFβ type I receptor by binding to αβ integrin on HSCs and to be secreted by MSCs from umbilical cord, teeth, and bone marrow. In mice, injection of recombinant human MFGE8 had anti-fibrotic effects comparable to those of the hpUCMSC secretome, reducing extracellular matrix deposition and HSC activation. Co-injection of an antibody against MFGE8 reduced the anti-fibrotic effects of the hpUCMSC secretome in mice. Levels of MFGE8 were reduced in cirrhotic liver tissue from patients compared with controls. CONCLUSIONS:MFGE8 is an anti-fibrotic protein in MSC secretomes that strongly inhibits TGFβ signaling and reduces extracellular matrix deposition and liver fibrosis in mice. 10.1053/j.gastro.2016.12.003
    Extracellular vesicles deposit to rejuvenate aged bone marrow-derived mesenchymal stem cells and slow age-related degeneration. Lei Qian,Gao Fei,Liu Teng,Ren Wenxiang,Chen Li,Cao Yulin,Chen Wenlan,Guo Shaojun,Zhang Qiong,Chen Weiqun,Wang Hongxiang,Chen Zhichao,Li Qiubai,Hu Yu,Guo An-Yuan Science translational medicine Stem cell senescence increases alongside the progressive functional declines that characterize aging. The effects of extracellular vesicles (EVs) are now attracting intense interest in the context of aging and age-related diseases. Here, we demonstrate that neonatal umbilical cord (UC) is a source of EVs derived from mesenchymal stem cells (MSC-EVs). These UC-produced MSC-EVs (UC-EVs) contain abundant anti-aging signals and rejuvenate senescing adult bone marrow-derived MSCs (AB-MSCs). UC-EV-rejuvenated AB-MSCs exhibited alleviated aging phenotypes and increased self-renewal capacity and telomere length. Mechanistically, UC-EVs rejuvenate AB-MSCs at least partially by transferring proliferating cell nuclear antigen () into recipient AB-MSCs. When tested in therapeutic context, UC-EV-triggered rejuvenation enhanced the regenerative capacities of AB-MSCs in bone formation, wound healing, and angiogenesis. Intravenously injected UC-EVs conferred anti-aging phenotypes including decreased bone and kidney degeneration in aged mice. Our findings reveal that UC-EVs are of high translational value in anti-aging intervention. 10.1126/scitranslmed.aaz8697
    Melatonin enhances the human mesenchymal stem cells motility via melatonin receptor 2 coupling with Gαq in skin wound healing. Lee Sei-Jung,Jung Young Hyun,Oh Sang Yub,Yun Seung Pil,Han Ho Jae Journal of pineal research Melatonin, a circadian rhythm-promoting molecule, has a variety of biological functions, but the functional role of melatonin in the motility of mesenchymal stem cells (MSCs) has yet to be studied. In a mouse skin excisional wound model, we found that transplantation of umbilical cord blood (UCB)-MSCs pretreated with melatonin enhanced wound closure, granulation, and re-epithelialization at mouse skin wound sites, where relatively more UCB-MSCs which were engrafted onto the wound site were detected. Thus, we identified the signaling pathway of melatonin, which affects the motility of UCB-MSCs. Melatonin (1 μm) significantly increased the motility of UCB-MSCs, which had been inhibited by the knockdown of melatonin receptor 2 (MT2). We found that Gαq coupled with MT2 and that the binding of Gαq to MT2 uniquely stimulated an atypical PKC isoform, PKCζ. Melatonin induced the phosphorylation of FAK and paxillin, which were concurrently downregulated by blocking of the PKC activity. Melatonin increased the levels of active Cdc42 and Arp2/3, and it has the ability to stimulate cytoskeletal reorganization-related proteins such as profilin-1, cofilin-1, and F-actin in UCB-MSCs. Finally, a lack of MT2 expression in UCB-MSCs during a mouse skin transplantation experiment resulted in impaired wound healing and less engraftment of stem cells at the wound site. These results demonstrate that melatonin signaling via MT2 triggers FAK/paxillin phosphorylation to stimulate reorganization of the actin cytoskeleton, which is responsible for Cdc42/Arp2/3 activation to promote UCB-MSCs motility. 10.1111/jpi.12179