HMGB1 promotes ductular reaction and tumorigenesis in autophagy-deficient livers. Khambu Bilon,Huda Nazmul,Chen Xiaoyun,Antoine Daniel J,Li Yong,Dai Guoli,Köhler Ulrike A,Zong Wei-Xing,Waguri Satoshi,Werner Sabine,Oury Tim D,Dong Zheng,Yin Xiao-Ming The Journal of clinical investigation Autophagy is important for liver homeostasis, and the deficiency leads to injury, inflammation, ductular reaction (DR), fibrosis, and tumorigenesis. It is not clear how these events are mechanistically linked to autophagy deficiency. Here, we reveal the role of high-mobility group box 1 (HMGB1) in two of these processes. First, HMGB1 was required for DR, which represents the expansion of hepatic progenitor cells (HPCs) implicated in liver repair and regeneration. DR caused by hepatotoxic diets (3,5-diethoxycarbonyl-1,4-dihydrocollidine [DDC] or choline-deficient, ethionine-supplemented [CDE]) also depended on HMGB1, indicating that HMGB1 may be generally required for DR in various injury scenarios. Second, HMGB1 promoted tumor progression in autophagy-deficient livers. Receptor for advanced glycation end product (RAGE), a receptor for HMGB1, was required in the same two processes and could mediate the proliferative effects of HMBG1 in isolated HPCs. HMGB1 was released from autophagy-deficient hepatocytes independently of cellular injury but depended on NRF2 and the inflammasome, which was activated by NRF2. Pharmacological or genetic activation of NRF2 alone, without disabling autophagy or causing injury, was sufficient to cause inflammasome-dependent HMGB1 release. In conclusion, HMGB1 release is a critical mechanism in hepatic pathogenesis under autophagy-deficient conditions and leads to HPC expansion as well as tumor progression. 10.1172/JCI91814
    Signalling via the osteopontin and high mobility group box-1 axis drives the fibrogenic response to liver injury. Arriazu Elena,Ge Xiaodong,Leung Tung-Ming,Magdaleno Fernando,Lopategi Aritz,Lu Yongke,Kitamura Naoto,Urtasun Raquel,Theise Neil,Antoine Daniel J,Nieto Natalia Gut OBJECTIVE:Liver fibrosis is associated with significant collagen-I deposition largely produced by activated hepatic stellate cells (HSCs); yet, the link between hepatocyte damage and the HSC profibrogenic response remains unclear. Here we show significant induction of osteopontin (OPN) and high-mobility group box-1 (HMGB1) in liver fibrosis. Since OPN was identified as upstream of HMGB1, we hypothesised that OPN could participate in the pathogenesis of liver fibrosis by increasing HMGB1 to upregulate collagen-I expression. DESIGN AND RESULTS:Patients with long-term hepatitis C virus (HCV) progressing in disease stage displayed enhanced hepatic OPN and HMGB1 immunostaining, which correlated with fibrosis stage, whereas it remained similar in non-progressors. Hepatocyte cytoplasmic OPN and HMGB1 expression was significant while loss of nuclear HMGB1 occurred in patients with HCV-induced fibrosis compared with healthy explants. Well-established liver fibrosis along with marked induction of HMGB1 occurred in CCl-injected transgenic yet it was less in wild type and almost absent in mice. ablation in hepatocytes () protected mice from CCl-induced liver fibrosis. Coculture with hepatocytes that secrete OPN plus HMGB1 and challenge with recombinant OPN (rOPN) or HMGB1 (rHMGB1) enhanced collagen-I expression in HSCs, which was blunted by neutralising antibodies (Abs) and by or ablation. rOPN induced acetylation of HMGB1 in HSCs due to increased NADPH oxidase activity and the associated decrease in histone deacetylases 1/2 leading to upregulation of collagen-I. Last, rHMGB1 signalled via receptor for advanced glycation end-products and activated the PI3K-pAkt1/2/3 pathway to upregulate collagen-I. CONCLUSIONS:During liver fibrosis, the increase in OPN induces HMGB1, which acts as a downstream alarmin driving collagen-I synthesis in HSCs. 10.1136/gutjnl-2015-310752
    Melatonin attenuates D-galactose-induced memory impairment, neuroinflammation and neurodegeneration via RAGE/NF-K B/JNK signaling pathway in aging mouse model. Ali Tahir,Badshah Haroon,Kim Tae Hyun,Kim Myeong Ok Journal of pineal research Melatonin acts as a pleiotropic agent in various age-related neurodegenerative diseases. In this study, we examined the underlying neuroprotective mechanism of melatonin against D-galactose-induced memory and synaptic dysfunction, elevated reactive oxygen species (ROS), neuroinflammation and neurodegeneration. D-galactose was administered (100 mg/kg intraperitoneally (i.p.)) for 60 days. After 30 days of D-galactose administration, vehicle (same volume) or melatonin (10 mg/kg, i.p.) was administered for 30 days. Our behavioral (Morris water maze and Y-maze test) results revealed that chronic melatonin treatment alleviated D-galactose-induced memory impairment. Additionally, melatonin treatment reversed D-galactose-induced synaptic disorder via increasing the level of memory-related pre-and postsynaptic protein markers. We also determined that melatonin enhances memory function in the D-galactose-treated mice possibly via reduction of elevated ROS and receptor for advanced glycation end products (RAGE). Furthermore, Western blot and morphological results showed that melatonin treatment significantly reduced D-galactose-induced neuroinflammation through inhibition of microgliosis (Iba-1) and astrocytosis (GFAP), and downregulating other inflammatory mediators such as p-IKKβ, p-NF-K B65, COX2, NOS2, IL-1β, and TNFα. Moreover, melatonin lowered the oxidative stress kinase p-JNK which suppressed various apoptotic markers, that is, cytochrome C, caspase-9, caspase-3 and PARP-1, and prevent neurodegeneration. Hence, melatonin attenuated the D-galactose-induced memory impairment, neuroinflammation and neurodegeneration possibly through RAGE/NF-K B/JNK pathway. Taken together, our data suggest that melatonin could be a promising, safe and endogenous compatible antioxidant candidate for age-related neurodegenerative diseases such as Alzheimer's disease (AD). 10.1111/jpi.12194
    Neutrophil-derived S100 calcium-binding proteins A8/A9 promote reticulated thrombocytosis and atherogenesis in diabetes. Kraakman Michael J,Lee Man Ks,Al-Sharea Annas,Dragoljevic Dragana,Barrett Tessa J,Montenont Emilie,Basu Debapriya,Heywood Sarah,Kammoun Helene L,Flynn Michelle,Whillas Alexandra,Hanssen Nordin Mj,Febbraio Mark A,Westein Erik,Fisher Edward A,Chin-Dusting Jaye,Cooper Mark E,Berger Jeffrey S,Goldberg Ira J,Nagareddy Prabhakara R,Murphy Andrew J The Journal of clinical investigation Platelets play a critical role in atherogenesis and thrombosis-mediated myocardial ischemia, processes that are accelerated in diabetes. Whether hyperglycemia promotes platelet production and whether enhanced platelet production contributes to enhanced atherothrombosis remains unknown. Here we found that in response to hyperglycemia, neutrophil-derived S100 calcium-binding proteins A8/A9 (S100A8/A9) interact with the receptor for advanced glycation end products (RAGE) on hepatic Kupffer cells, resulting in increased production of IL-6, a pleiotropic cytokine that is implicated in inflammatory thrombocytosis. IL-6 acts on hepatocytes to enhance the production of thrombopoietin, which in turn interacts with its cognate receptor c-MPL on megakaryocytes and bone marrow progenitor cells to promote their expansion and proliferation, resulting in reticulated thrombocytosis. Lowering blood glucose using a sodium-glucose cotransporter 2 inhibitor (dapagliflozin), depleting neutrophils or Kupffer cells, or inhibiting S100A8/A9 binding to RAGE (using paquinimod), all reduced diabetes-induced thrombocytosis. Inhibiting S100A8/A9 also decreased atherogenesis in diabetic mice. Finally, we found that patients with type 2 diabetes have reticulated thrombocytosis that correlates with glycated hemoglobin as well as increased plasma S100A8/A9 levels. These studies provide insights into the mechanisms that regulate platelet production and may aid in the development of strategies to improve on current antiplatelet therapies and to reduce cardiovascular disease risk in diabetes. 10.1172/JCI92450
    The HMGB1-RAGE axis mediates traumatic brain injury-induced pulmonary dysfunction in lung transplantation. Weber Daniel J,Gracon Adam S A,Ripsch Matthew S,Fisher Amanda J,Cheon Bo M,Pandya Pankita H,Vittal Ragini,Capitano Maegan L,Kim Youngsong,Allette Yohance M,Riley Amanda A,McCarthy Brian P,Territo Paul R,Hutchins Gary D,Broxmeyer Hal E,Sandusky George E,White Fletcher A,Wilkes David S Science translational medicine Traumatic brain injury (TBI) results in systemic inflammatory responses that affect the lung. This is especially critical in the setting of lung transplantation, where more than half of donor allografts are obtained postmortem from individuals with TBI. The mechanism by which TBI causes pulmonary dysfunction remains unclear but may involve the interaction of high-mobility group box-1 (HMGB1) protein with the receptor for advanced glycation end products (RAGE). To investigate the role of HMGB1 and RAGE in TBI-induced lung dysfunction, RAGE-sufficient (wild-type) or RAGE-deficient (RAGE(-/-)) C57BL/6 mice were subjected to TBI through controlled cortical impact and studied for cardiopulmonary injury. Compared to control animals, TBI induced systemic hypoxia, acute lung injury, pulmonary neutrophilia, and decreased compliance (a measure of the lungs' ability to expand), all of which were attenuated in RAGE(-/-) mice. Neutralizing systemic HMGB1 induced by TBI reversed hypoxia and improved lung compliance. Compared to wild-type donors, lungs from RAGE(-/-) TBI donors did not develop acute lung injury after transplantation. In a study of clinical transplantation, elevated systemic HMGB1 in donors correlated with impaired systemic oxygenation of the donor lung before transplantation and predicted impaired oxygenation after transplantation. These data suggest that the HMGB1-RAGE axis plays a role in the mechanism by which TBI induces lung dysfunction and that targeting this pathway before transplant may improve recipient outcomes after lung transplantation. 10.1126/scitranslmed.3009443
    Extracellular HMGB1 promotes differentiation of nurse-like cells in chronic lymphocytic leukemia. Jia Li,Clear Andrew,Liu Feng-Ting,Matthews Janet,Uddin Nadiha,McCarthy Aine,Hoxha Elena,Durance Catherine,Iqbal Sameena,Gribben John G Blood Chronic lymphocytic leukemia (CLL) is a disease of an accumulation of mature B cells that are highly dependent on the microenvironment for maintenance and expansion. However, little is known regarding the mechanisms whereby CLL cells create their favorable microenvironment for survival. High-mobility group protein B-1 (HMGB1) is a highly conserved nuclear protein that can be actively secreted by innate immune cells and passively released by injured or dying cells. We found significantly increased HMGB1 levels in the plasma of CLL patients compared with healthy controls, and HMGB1 concentration is associated with absolute lymphocyte count. We therefore sought to determine potential roles of HMGB1 in modulating the CLL microenvironment. CLL cells passively released HMGB1, and the timing and concentrations of HMGB1 in the medium were associated with differentiation of nurse-like cells (NLCs). Higher CD68 expression in CLL lymph nodes, one of the markers for NLCs, was associated with shorter overall survival of CLL patients. HMGB1-mediated NLC differentiation involved internalization of both receptor for advanced glycation end products (RAGE) and Toll-like receptor-9 (TLR9). Differentiation of NLCs can be prevented by blocking the HMGB1-RAGE-TLR9 pathway. In conclusion, this study demonstrates for the first time that CLL cells might modulate their microenvironment by releasing HMGB1. 10.1182/blood-2013-10-529610
    The HMGB1/RAGE axis triggers neutrophil-mediated injury amplification following necrosis. Huebener Peter,Pradere Jean-Philippe,Hernandez Celine,Gwak Geum-Youn,Caviglia Jorge Matias,Mu Xueru,Loike John D,Schwabe Robert F The Journal of clinical investigation In contrast to microbially triggered inflammation, mechanisms promoting sterile inflammation remain poorly understood. Damage-associated molecular patterns (DAMPs) are considered key inducers of sterile inflammation following cell death, but the relative contribution of specific DAMPs, including high-mobility group box 1 (HMGB1), is ill defined. Due to the postnatal lethality of Hmgb1-knockout mice, the role of HMGB1 in sterile inflammation and disease processes in vivo remains controversial. Here, using conditional ablation strategies, we have demonstrated that epithelial, but not bone marrow-derived, HMGB1 is required for sterile inflammation following injury. Epithelial HMGB1, through its receptor RAGE, triggered recruitment of neutrophils, but not macrophages, toward necrosis. In clinically relevant models of necrosis, HMGB1/RAGE-induced neutrophil recruitment mediated subsequent amplification of injury, depending on the presence of neutrophil elastase. Notably, hepatocyte-specific HMGB1 ablation resulted in 100% survival following lethal acetaminophen intoxication. In contrast to necrosis, HMGB1 ablation did not alter inflammation or mortality in response to TNF- or FAS-mediated apoptosis. In LPS-induced shock, in which HMGB1 was considered a key mediator, HMGB1 ablation did not ameliorate inflammation or lethality, despite efficient reduction of HMGB1 serum levels. Our study establishes HMGB1 as a bona fide and targetable DAMP that selectively triggers a neutrophil-mediated injury amplification loop in the setting of necrosis. 10.1172/JCI76887
    Higher levels of advanced glycation endproducts in human carotid atherosclerotic plaques are associated with a rupture-prone phenotype. Hanssen Nordin M J,Wouters Kristiaan,Huijberts Maya S,Gijbels Marion J,Sluimer Judith C,Scheijen Jean L J M,Heeneman Sylvia,Biessen Erik A L,Daemen Mat J A P,Brownlee Michael,de Kleijn Dominique P,Stehouwer Coen D A,Pasterkamp Gerard,Schalkwijk Casper G European heart journal AIMS:Rupture-prone atherosclerotic plaques are characterized by inflammation and a large necrotic core. Inflammation is linked to high metabolic activity. Advanced glycation endproducts (AGEs) and their major precursor methylglyoxal are formed during high metabolic activity and can have detrimental effects on cellular function and may induce cell death. Therefore, we investigated whether plaque AGEs are increased in human carotid rupture-prone plaques and are associated with plaque inflammation and necrotic core formation. METHODS AND RESULTS:The protein-bound major methylglyoxal-derived AGE 5-hydro-5-methylimidazolone (MG-H1) and N(ε)-(carboxymethyl)lysine (CML) were measured in human carotid endarterectomy specimens (n = 75) with tandem mass spectrometry. MG-H1 and CML levels were associated with rupture-prone plaques, increased protein levels of the inflammatory mediators IL-8 and MCP-1 and with higher MMP-9 activity. Immunohistochemistry showed that AGEs accumulated predominantly in macrophages surrounding the necrotic core and co-localized with cleaved caspase-3. Intra-plaque comparison revealed that glyoxalase-1 (GLO-1), the major methylglyoxal-detoxifying enzyme, mRNA was decreased (-13%, P < 0.05) in ruptured compared with stable plaque segments. In line, in U937 monoctyes, we found reduced (GLO-1) activity (-38%, P < 0.05) and increased MGO (346%, P < 0.05) production after stimulation with the inflammatory mediator TNF. Direct incubation with methylglyoxal increased apoptosis up to two-fold. CONCLUSION:This is the first study showing that AGEs are associated with human rupture-prone plaques. Furthermore, this study suggests a cascade linking inflammation, reduced GLO-1, methylglyoxal- and AGE-accumulation, and subsequent apoptosis. Thereby, AGEs may act as mediators of the progression of stable to rupture-prone plaques, opening a window towards novel treatments and biomarkers to treat cardiovascular diseases. 10.1093/eurheartj/eht402
    Diabetes, aging, and their tissue complications. Bucala Rick The Journal of clinical investigation The inactivation of NO by advanced glycation endproducts (AGEs), which accumulate on tissue proteins as a function of age and hyperglycemia, focused attention on the role of these ubiquitous posttranslational modifications in acquired impairments of vascular reactivity and other signaling processes. This observation occurred during a watershed period of basic and translational research in glycation that encompassed new pathologic phenomena and novel intervention strategies. How has the AGE paradigm for the tissue complications of aging and diabetes fared since the identification of the link between these glycation products and NO inactivation, and what lessons may be offered for future investigations? 10.1172/JCI75224
    Dietary advanced glycation end products and their relevance for human health. Nowotny Kerstin,Schröter David,Schreiner Monika,Grune Tilman Ageing research reviews Due to their bioactivity and harmful potential, advanced glycation end products (AGEs) are discussed to affect human health. AGEs are compounds formed endogenously in the human body andexogenously, especially, in foods while thermal processing. In contrast to endogenous AGEs, dietary AGEs are formed in much higher extent. However, their risk potential is also depending on absorption, distribution, metabolism and elimination. For over 10 years an intense debate on the risk of dietary AGEs on human health is going on. On the one hand, studies provided evidence that dietary AGEs contribute to clinical outcomes. On the other hand, human studies failed to observe any association. Because it was not possible to draw a final conclusion, the call for new interdisciplinary approaches arose. In this review, we will give an overview on the current state of scientific knowledge in this field. In particular, we focus on (I) the occurrence of AGEs in foods and the daily uptake of AGEs, (II) contribution to endogenous levels and (III) the effect on health-/disease-related biomarkers in humans. 10.1016/j.arr.2018.06.005
    Plasma sRAGE is independently associated with increased mortality in ARDS: a meta-analysis of individual patient data. Jabaudon Matthieu,Blondonnet Raiko,Pereira Bruno,Cartin-Ceba Rodrigo,Lichtenstern Christoph,Mauri Tommaso,Determann Rogier M,Drabek Tomas,Hubmayr Rolf D,Gajic Ognjen,Uhle Florian,Coppadoro Andrea,Pesenti Antonio,Schultz Marcus J,Ranieri Marco V,Brodska Helena,Mrozek Ségolène,Sapin Vincent,Matthay Michael A,Constantin Jean-Michel,Calfee Carolyn S Intensive care medicine PURPOSE:The soluble receptor for advanced glycation end-products (sRAGE) is a marker of lung epithelial injury and alveolar fluid clearance (AFC), with promising values for assessing prognosis and lung injury severity in acute respiratory distress syndrome (ARDS). Because AFC is impaired in most patients with ARDS and is associated with higher mortality, we hypothesized that baseline plasma sRAGE would predict mortality, independently of two key mediators of ventilator-induced lung injury. METHODS:We conducted a meta-analysis of individual data from 746 patients enrolled in eight prospective randomized and observational studies in which plasma sRAGE was measured in ARDS articles published through March 2016. The primary outcome was 90-day mortality. Using multivariate and mediation analyses, we tested the association between baseline plasma sRAGE and mortality, independently of driving pressure and tidal volume. RESULTS:Higher baseline plasma sRAGE [odds ratio (OR) for each one-log increment, 1.18; 95% confidence interval (CI) 1.01-1.38; P = 0.04], driving pressure (OR for each one-point increment, 1.04; 95% CI 1.02-1.07; P = 0.002), and tidal volume (OR for each one-log increment, 1.98; 95% CI 1.07-3.64; P = 0.03) were independently associated with higher 90-day mortality in multivariate analysis. Baseline plasma sRAGE mediated a small fraction of the effect of higher ΔP on mortality but not that of higher V. CONCLUSIONS:Higher baseline plasma sRAGE was associated with higher 90-day mortality in patients with ARDS, independently of driving pressure and tidal volume, thus reinforcing the likely contribution of alveolar epithelial injury as an important prognostic factor in ARDS. Registration: PROSPERO (ID: CRD42018100241). 10.1007/s00134-018-5327-1
    Dietary glycotoxins exacerbate progression of experimental fatty liver disease. Leung Christopher,Herath Chandana B,Jia Zhiyuan,Goodwin Michelle,Mak Kai Yan,Watt Matthew J,Forbes Josephine M,Angus Peter W Journal of hepatology BACKGROUND & AIMS:Advanced glycation end-products (AGEs) levels are high in western diets and contribute to tissue injury via activation of RAGE (receptor for AGEs) and generation of reactive oxygen species (ROS). Here, we determined if high dietary AGE intake worsens progression of non-alcoholic fatty liver disease (NAFLD). METHODS:Male Sprague Dawley rats were fed a methionine choline deficient (MCD) diet for 6 weeks before 6 weeks of a high AGE MCD diet through baking. They were compared with animals on MCD diet or a methionine choline replete (MCR) diet alone for 12 weeks. Hepatic ROS, triglycerides, biochemistry, picro-sirius morphometry, hepatic mRNA expression and immunohistochemistry were determined. Primary hepatic stellate cells (HSCs) from both MCR and MCD animals were exposed to AGEs. ROS, proliferation and mRNA expression were determined. RESULTS:The high AGE MCD diet increased hepatic AGE content and elevated triglycerides, NADPH dependent superoxide production, HNE adducts, steatosis, steatohepatitis (CD43, IL-6, TNF-α) and fibrosis (α-SMA, CTGF, COL1A, picrosirius) compared to MCD alone. In HSCs, AGEs significantly increased ROS production, bromodeoxyuridine proliferation and MCP-1, IL-6, α-SMA, and RAGE expression in HSCs from MCD but not MCR animals. These effects were abrogated by RAGE or NADPH oxidase blockade. CONCLUSIONS:In the MCD model of NAFLD, high dietary AGEs increases hepatic AGE content and exacerbates liver injury, inflammation, and liver fibrosis via oxidative stress and RAGE dependent profibrotic effects of AGEs on activated HSCs. This suggests that pharmacological and dietary strategies targeting the AGE/RAGE pathway could slow the progression of NAFLD. 10.1016/j.jhep.2013.11.033
    Receptor for advanced glycation end products and its ligand high-mobility group box-1 mediate allergic airway sensitization and airway inflammation. Ullah Md Ashik,Loh Zhixuan,Gan Wan Jun,Zhang Vivian,Yang Huan,Li Jian Hua,Yamamoto Yasuhiko,Schmidt Ann Marie,Armour Carol L,Hughes J Margaret,Phipps Simon,Sukkar Maria B The Journal of allergy and clinical immunology BACKGROUND:The receptor for advanced glycation end products (RAGE) shares common ligands and signaling pathways with TLR4, a key mediator of house dust mite (Dermatophagoides pteronyssinus) (HDM) sensitization. We hypothesized that RAGE and its ligand high-mobility group box-1 (HMGB1) cooperate with TLR4 to mediate HDM sensitization. OBJECTIVES:To determine the requirement for HMGB1 and RAGE, and their relationship with TLR4, in airway sensitization. METHODS:TLR4(-/-), RAGE(-/-), and RAGE-TLR4(-/-) mice were intranasally exposed to HDM or cockroach (Blatella germanica) extracts, and features of allergic inflammation were measured during the sensitization or challenge phase. Anti-HMGB1 antibody and the IL-1 receptor antagonist Anakinra were used to inhibit HMGB1 and the IL-1 receptor, respectively. RESULTS:The magnitude of allergic airway inflammation in response to either HDM or cockroach sensitization and/or challenge was significantly reduced in the absence of RAGE but not further diminished in the absence of both RAGE and TLR4. HDM sensitization induced the release of HMGB1 from the airway epithelium in a biphasic manner, which corresponded to the sequential activation of TLR4 then RAGE. Release of HMGB1 in response to cockroach sensitization also was RAGE dependent. Significantly, HMGB1 release occurred downstream of TLR4-induced IL-1α, and upstream of IL-25 and IL-33 production. Adoptive transfer of HDM-pulsed RAGE(+/+)dendritic cells to RAGE(-/-) mice recapitulated the allergic responses after HDM challenge. Immunoneutralization of HMGB1 attenuated HDM-induced allergic airway inflammation. CONCLUSION:The HMGB1-RAGE axis mediates allergic airway sensitization and airway inflammation. Activation of this axis in response to different allergens acts to amplify the allergic inflammatory response, which exposes it as an attractive target for therapeutic intervention. 10.1016/j.jaci.2013.12.1035
    Polyphosphate amplifies proinflammatory responses of nuclear proteins through interaction with receptor for advanced glycation end products and P2Y1 purinergic receptor. Dinarvand Peyman,Hassanian Seyed Mahdi,Qureshi Shabir H,Manithody Chandrashekhara,Eissenberg Joel C,Yang Likui,Rezaie Alireza R Blood The extracellular nuclear proteins, histone H4 (H4) and high mobility group box 1 (HMGB1), released by injured cells during the activation of inflammation and coagulation pathways provoke potent inflammatory responses through interaction with pathogen-related pattern recognition receptors (ie, Toll-like receptors [TLRs] and receptor for advanced glycation end products [RAGE]) present on vascular and innate immune cells. Inorganic polyphosphate (polyP) has emerged as a key modulator of coagulation and inflammation. Here, we demonstrate that polyP binds to both H4 and HMGB1 with high affinity, thereby dramatically potentiating their proinflammatory properties in cellular and in vivo models. By using small interfering RNA knockdowns, pharmacologic inhibitors and extracellular domains of the receptors TLR2, TLR4, RAGE, and P2Y1 as competitive inhibitors, we demonstrate that polyP amplifies H4- and HMGB1-mediated inflammatory signaling in human umbilical vein endothelial cells specifically through interaction with the RAGE and P2Y1 receptors, thereby eliciting intracellular Ca(2+) release. Finally, we demonstrate that the natural anticoagulant protease, activated protein C, potently inhibits polyP-mediated proinflammatory effects of both nuclear proteins in cellular and in vivo systems. 10.1182/blood-2013-09-529602
    Restriction of advanced glycation end products improves insulin resistance in human type 2 diabetes: potential role of AGER1 and SIRT1. Uribarri Jaime,Cai Weijing,Ramdas Maya,Goodman Susan,Pyzik Renata,Chen Xue,Zhu Li,Striker Gary E,Vlassara Helen Diabetes care OBJECTIVE:Increased oxidative stress (OS) and impaired anti-OS defenses are important in the development and persistence of insulin resistance (IR). Several anti-inflammatory and cell-protective mechanisms, including advanced glycation end product (AGE) receptor-1 (AGER1) and sirtuin (silent mating-type information regulation 2 homolog) 1 (SIRT1) are suppressed in diabetes. Because basal OS in type 2 diabetic patients is influenced by the consumption of AGEs, we examined whether AGE consumption also affects IR and whether AGER1 and SIRT1 are involved. RESEARCH DESIGN AND METHODS:The study randomly assigned 36 subjects, 18 type 2 diabetic patients (age 61±4 years) and 18 healthy subjects (age 67±1.4 years), to a standard diet (>20 AGE equivalents [Eq]/day) or an isocaloric AGE-restricted diet (<10 AGE Eq/day) for 4 months. Circulating metabolic and inflammatory markers were assessed. Expression and activities of AGER1 and SIRT1 were examined in patients' peripheral blood mononuclear cells (PMNC) and in AGE-stimulated, AGER1-transduced (AGER1+), or AGER1-silenced human monocyte-like THP-1 cells. RESULTS:Insulin and homeostasis model assessment, leptin, tumor necrosis factor-α and nuclear factor-κB p65 acetylation, serum AGEs, and 8-isoprostanes decreased in AGE-restricted type 2 diabetic patients, whereas PMNC AGER1 and SIRT1 mRNA, and protein levels normalized and adiponectin markedly increased. AGEs suppressed AGER1, SIRT-1, and NAD+ levels in THP-1 cells. These effects were inhibited in AGER1+ but were enhanced in AGER1-silenced cells. CONCLUSIONS:Food-derived pro-oxidant AGEs may contribute to IR in clinical type 2 diabetes and suppress protective mechanisms, AGER1 and SIRT1. AGE restriction may preserve native defenses and insulin sensitivity by maintaining lower basal OS. 10.2337/dc11-0091
    Circulating soluble receptor for advanced glycation end products (sRAGE) as a biomarker of emphysema and the RAGE axis in the lung. Yonchuk John G,Silverman Edwin K,Bowler Russell P,Agustí Alvar,Lomas David A,Miller Bruce E,Tal-Singer Ruth,Mayer Ruth J American journal of respiratory and critical care medicine Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous disease that has been traditionally characterized by incompletely reversible airflow limitation. Yet, the latter is poorly correlated with many other clinically relevant characteristics of the disease. Thus, the identification of biomarkers to more accurately assess this heterogeneity and disease severity may facilitate the discovery and development of new treatments and better management of patients with COPD. One molecule that has attracted attention as a potentially useful biomarker specifically for the emphysema subpopulation is the soluble receptor for advanced glycation end products (sRAGE). As the soluble isoform of a key proinflammatory signaling receptor, sRAGE acts as a "decoy" for RAGE ligands and prevents their interaction with the receptor. Multiple reports have now linked sRAGE to COPD, and more specifically to emphysema, and evidence is accumulating that this link is likely mechanistic in nature. Here we review the current state of knowledge about sRAGE biology, the mechanistic links to COPD, and the evidence for using it as a biomarker for emphysema. We also discuss sRAGE as a potential target for therapeutic intervention in COPD. 10.1164/rccm.201501-0137PP
    Advanced glycation end products induce a prothrombotic phenotype in mice via interaction with platelet CD36. Zhu Weifei,Li Wei,Silverstein Roy L Blood Diabetes mellitus has been associated with platelet hyperreactivity, which plays a central role in the hyperglycemia-related prothrombotic phenotype. The mechanisms responsible for this phenomenon are not established. In the present study, we investigated the role of CD36, a class-B scavenger receptor, in this process. Using both in vitro and in vivo mouse models, we demonstrated direct and specific interactions of platelet CD36 with advanced glycation end products (AGEs) generated under hyperglycemic conditions. AGEs bound to platelet CD36 in a specific and dose-dependent manner, and binding was inhibited by the high-affinity CD36 ligand NO(2)LDL. Cd36-null platelets did not bind AGE. Using diet- and drug-induced mouse models of diabetes, we have shown that cd36-null mice had a delayed time to the formation of occlusive thrombi compared with wild-type (WT) in a FeCl(3)-induced carotid artery injury model. Cd36-null mice had a similar level of hyperglycemia and a similar level of plasma AGEs compared with WT mice under this condition, but WT mice had more AGEs incorporated into thrombi. Mechanistic studies revealed that CD36-dependent JNK2 activation is involved in this prothrombotic pathway. Therefore, the results of the present study couple vascular complications in diabetes mellitus with AGE-CD36-mediated platelet signaling and hyperreactivity. 10.1182/blood-2011-10-387506
    Consumption of a diet low in advanced glycation end products for 4 weeks improves insulin sensitivity in overweight women. Mark Alicja Budek,Poulsen Malene Wibe,Andersen Stine,Andersen Jeanette Marker,Bak Monika Judyta,Ritz Christian,Holst Jens Juul,Nielsen John,de Courten Barbora,Dragsted Lars Ove,Bügel Susanne Gjedsted Diabetes care OBJECTIVE High-heat cooking of food induces the formation of advanced glycation end products (AGEs), which are thought to impair glucose metabolism in type 2 diabetic patients. High intake of fructose might additionally affect endogenous formation of AGEs. This parallel intervention study investigated whether the addition of fructose or cooking methods influencing the AGE content of food affect insulin sensitivity in overweight individuals. RESEARCH DESIGN AND METHODS Seventy-four overweight women were randomized to follow either a high- or low-AGE diet for 4 weeks, together with consumption of either fructose or glucose drinks. Glucose and insulin concentrations-after fasting and 2 h after an oral glucose tolerance test-were measured before and after the intervention. Homeostasis model assessment of insulin resistance (HOMA-IR) and insulin sensitivity index were calculated. Dietary and urinary AGE concentrations were measured (liquid chromatography tandem mass spectrometry) to estimate AGE intake and excretion. RESULTS When adjusted for changes in anthropometric measures during the intervention, the low-AGE diet decreased urinary AGEs, fasting insulin concentrations, and HOMA-IR, compared with the high-AGE diet. Addition of fructose did not affect any outcomes. CONCLUSIONS Diets with high AGE content may increase the development of insulin resistance. AGEs can be reduced by modulation of cooking methods but is unaffected by moderate fructose intake. 10.2337/dc13-0842
    Soluble receptor for advanced glycation end products and risk of liver cancer. Moy Kristin A,Jiao Li,Freedman Neal D,Weinstein Stephanie J,Sinha Rashmi,Virtamo Jarmo,Albanes Demetrius,Stolzenberg-Solomon Rachael Z Hepatology (Baltimore, Md.) UNLABELLED:Binding of advanced glycation end products (AGEs) to their receptor (RAGE) increases oxidative stress and inflammation and may be involved in liver injury and subsequent carcinogenesis. Soluble RAGE (sRAGE) may neutralize the effects mediated by the AGE/RAGE complex. Epidemiologic studies examining sRAGE or AGEs in association with liver cancer are lacking. We examined the associations between prediagnostic serum concentrations of sRAGE or Nϵ-(carboxymethyl)-lysine (CML)-AGE and hepatocellular carcinoma in a case-cohort study within a cohort of 29,133 Finnish male smokers who completed questionnaires and provided a fasting blood sample between 1985 and 1988. During follow-up beginning 5 years after enrollment through April 2006, 145 liver cancers occurred. Serum concentrations of sRAGE, CML-AGE, glucose, and insulin were measured in case subjects and 485 randomly sampled cohort participants. Chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) were available in most cases and in a subset of the study population. Weighted Cox proportional hazards regression was used to calculate relative risks (RR) and 95% confidence intervals (CI) adjusted for age, years of smoking, and body mass index. sRAGE and CML-AGE concentrations were inversely associated with liver cancer. Further adjustment for glucose and insulin or exclusion of case subjects with chronic HBV or HCV did not change the associations. CONCLUSION:Our results support the hypothesis that sRAGE is inversely associated with liver cancer. The findings need confirmation, particularly in populations that include women and nonsmokers. (HEPATOLOGY 2013 ). 10.1002/hep.26264
    Ratio of serum levels of AGEs to soluble form of RAGE is a predictor of endothelial function. Kajikawa Masato,Nakashima Ayumu,Fujimura Noritaka,Maruhashi Tatsuya,Iwamoto Yumiko,Iwamoto Akimichi,Matsumoto Takeshi,Oda Nozomu,Hidaka Takayuki,Kihara Yasuki,Chayama Kazuaki,Goto Chikara,Aibara Yoshiki,Noma Kensuke,Takeuchi Masayoshi,Matsui Takanori,Yamagishi Sho-Ichi,Higashi Yukihito Diabetes care OBJECTIVE:Advanced glycation end products (AGEs) and their specific receptor, the receptor for AGEs (RAGE), play an important role in atherosclerosis. Recently, a soluble form of RAGE (sRAGE) has been identified in human serum. However, the role of sRAGE in cardiovascular disease is still controversial. There is no information on the association between simultaneous measurements of AGEs and sRAGE and vascular function. In this study, we evaluated the associations between serum levels of AGEs and sRAGE, ratio of AGEs to sRAGE, and vascular function. RESEARCH DESIGN AND METHODS:We measured serum levels of AGEs and sRAGE and assessed vascular function by measurement of flow-mediated vasodilation (FMD) and nitroglycerine-induced vasodilation in 110 subjects who underwent health examinations. Multivariate regression analyses were performed to identify factors associated with vascular function. RESULTS:Univariate regression analysis revealed that FMD correlated with age, BMI, systolic blood pressure, diastolic blood pressure, heart rate, triglycerides, HDL cholesterol, glucose, smoking pack-years, nitroglycerine-induced vasodilation, serum levels of AGEs and sRAGE, and ratio of AGEs to sRAGE. Multivariate analysis revealed that the ratio of AGEs to sRAGE remained an independent predictor of FMD, while serum level of AGEs alone or sRAGE alone was not associated with FMD. CONCLUSIONS:These findings suggest that sRAGE may have a counterregulatory mechanism that is activated to counteract the vasotoxic effect of the AGE-RAGE axis. The ratio of AGEs to sRAGE may be a new chemical biomarker of endothelial function. 10.2337/dc14-1435
    Decrease in circulating concentrations of soluble receptors for advanced glycation end products at the time of seroconversion to autoantibody positivity in children with prediabetes. Salonen Kirsi M,Ryhänen Samppa J,Forbes Josephine M,Borg Danielle J,Härkönen Taina,Ilonen Jorma,Simell Olli,Veijola Riitta,Groop Per-Henrik,Knip Mikael Diabetes care OBJECTIVE:Dietary advanced glycation end products (AGEs) and their interactions with the receptor for AGEs (RAGE) may play a role in the pathogenesis of type 1 diabetes. This study set out to assess whether there is any association of circulating concentrations of soluble RAGE (sRAGE), AGEs, and their ratio with the appearance of diabetes-associated autoantibodies in children progressing to clinical diabetes. RESEARCH DESIGN AND METHODS:Serum concentrations of sRAGE, N-ε(carboxymethyl)lysine (CML) adducts, and the sRAGE/CML ratio were analyzed in children who progressed to type 1 diabetes. The samples were taken at four time points: before seroconversion, at the time of the first autoantibody-positive sample, at the time of the first sample positive for multiple (>2) autoantibodies, and close to the disease diagnosis. Samples of autoantibody-negative controls matched for age, sex, and HLA-conferred diabetes risk were analyzed at corresponding time points. RESULTS:The prediabetic children had higher sRAGE concentrations before seroconversion (Pc = 0.03), at the appearance of multiple autoantibodies (Pc = 0.008), and close to diagnosis (Pc = 0.04). Close to diagnosis, the cases had lower CML concentrations than the controls (Pc = 0.004). Prediabetic children had a higher sRAGE/CML ratio than the controls before seroconversion (Pc = 0.008) and at diagnosis (Pc < 0.001). CONCLUSIONS:Prediabetic children have higher concentrations of sRAGE and a higher sRAGE/CML ratio than healthy controls. Circulating sRAGE concentrations seem to decline with the appearance of diabetes-predictive autoantibodies in children progressing to type 1 diabetes. The higher sRAGE/CML ratio in prediabetic children may reflect a higher AGE scavenger capacity. 10.2337/dc14-1186
    Advanced glycation end-products (AGEs) and heart failure: pathophysiology and clinical implications. Hartog Jasper W L,Voors Adriaan A,Bakker Stephan J L,Smit Andries J,van Veldhuisen Dirk J European journal of heart failure Advanced glycation end-products (AGEs) are molecules formed during a non-enzymatic reaction between proteins and sugar residues, called the Maillard reaction. AGEs accumulate in the human body with age, and accumulation is accelerated in the presence of diabetes mellitus. In patients with diabetes, AGE accumulation is associated with the development of cardiac dysfunction. Enhanced AGE accumulation is not restricted to patients with diabetes, but can also occur in renal failure, enhanced states of oxidative stress, and by an increased intake of AGEs. Several lines of evidence suggest that AGEs are related to the development and progression of heart failure in non-diabetic patients as well. Preliminary small intervention studies with AGE cross-link breakers in heart failure patients have shown promising results. In this review, the role of AGEs in the development of heart failure and the role of AGE intervention as a possible treatment for heart failure are discussed. 10.1016/j.ejheart.2007.09.009
    Pulmonary receptor for advanced glycation end-products promotes asthma pathogenesis through IL-33 and accumulation of group 2 innate lymphoid cells. Oczypok Elizabeth A,Milutinovic Pavle S,Alcorn John F,Khare Anupriya,Crum Lauren T,Manni Michelle L,Epperly Michael W,Pawluk Adriane M,Ray Anuradha,Oury Tim D The Journal of allergy and clinical immunology BACKGROUND:Single nucleotide polymorphisms in the human gene for the receptor for advanced glycation end-products (RAGE) are associated with an increased incidence of asthma. RAGE is highly expressed in the lung and has been reported to play a vital role in the pathogenesis of murine models of asthma/allergic airway inflammation (AAI) by promoting expression of the type 2 cytokines IL-5 and IL-13. IL-5 and IL-13 are prominently secreted by group 2 innate lymphoid cells (ILC2s), which are stimulated by the proallergic cytokine IL-33. OBJECTIVE:We sought to test the hypothesis that pulmonary RAGE is necessary for allergen-induced ILC2 accumulation in the lung. METHODS:AAI was induced in wild-type and RAGE knockout mice by using IL-33, house dust mite extract, or Alternaria alternata extract. RAGE's lung-specific role in type 2 responses was explored with bone marrow chimeras and induction of gastrointestinal type 2 immune responses. RESULTS:RAGE was found to drive AAI by promoting IL-33 expression in response to allergen and by coordinating the inflammatory response downstream of IL-33. Absence of RAGE impedes pulmonary accumulation of ILC2s in models of AAI. Bone marrow chimera studies suggest that pulmonary parenchymal, but not hematopoietic, RAGE has a central role in promoting AAI. In contrast to the lung, the absence of RAGE does not affect IL-33-induced ILC2 influx in the spleen, type 2 cytokine production in the peritoneum, or mucus hypersecretion in the gastrointestinal tract. CONCLUSIONS:For the first time, this study demonstrates that a parenchymal factor, RAGE, mediates lung-specific accumulation of ILC2s. 10.1016/j.jaci.2015.03.011
    RAGE-induced asthma: A role for the receptor for advanced glycation end-products in promoting allergic airway disease. Brandt Eric B,Lewkowich Ian P The Journal of allergy and clinical immunology 10.1016/j.jaci.2019.06.012
    The receptor for advanced glycation end products is a critical mediator of type 2 cytokine signaling in the lungs. Perkins Timothy N,Oczypok Elizabeth A,Dutz Regina E,Donnell Mason L,Myerburg Michael M,Oury Tim D The Journal of allergy and clinical immunology BACKGROUND:Asthma is estimated to effect more than 300 million persons worldwide, leading to nearly 250,000 deaths annually. The majority of patients with mild-to-severe asthma have what is deemed "type-2 high" asthma, which is driven by the prototypical type 2 cytokines IL-4, IL-5, and IL-13. Studies have indicated that the receptor for advanced glycation end products (RAGE) is a critical molecule in the pathogenesis of experimental asthma/allergic airway inflammation. More specifically, RAGE expressed on stromal cells, rather than hematopoietic cells, is critical to induction of asthma/allergic airway inflammation by driving type 2 inflammatory responses. However, the role of RAGE in directly mediating type 2 cytokine signaling has never been investigated. OBJECTIVE:The goal of this study was to test the hypothesis that RAGE mediates type 2 cytokine-induced signal transduction, airway inflammation, and mucus metaplasia in the lungs. METHODS:Wild-type (WT) and RAGE knockout (RAGE) mice, were intranasally administered rIL-5/rIL-13 or rIL-4 alone, and signal transducer and activator of transcription 6 (STAT6) signaling, airway inflammation, and mucus metaplasia were assessed. A RAGE small-molecule antagonist was used to determine the effects of pharmacologically inhibiting RAGE on type 2 cytokine-induced effects. RESULTS:Administration of type 2 cytokines induced pronounced airway inflammation and mucus metaplasia in WT mice, which was nearly completely abrogated in RAGE mice. In addition, treatment with a RAGE-specific antagonist diminished the effects of type 2 cytokines in WT mice and in primary human bronchial epithelial cell cultures. Genetic ablation or pharmacologic inhibition of RAGE blocks the effects of IL-13 and IL-4 by inhibiting sustained STAT6 activation and downstream target gene expression in mice and in human bronchial epithelial cells. CONCLUSIONS:This study is the first to indicate that RAGE is a critical component of type 2 cytokine signal transduction mechanisms, which is a driving force behind type 2-high asthma. 10.1016/j.jaci.2019.03.019
    The Role of Advanced Glycation End Products in Aging and Metabolic Diseases: Bridging Association and Causality. Chaudhuri Jyotiska,Bains Yasmin,Guha Sanjib,Kahn Arnold,Hall David,Bose Neelanjan,Gugliucci Alejandro,Kapahi Pankaj Cell metabolism Accumulation of advanced glycation end products (AGEs) on nucleotides, lipids, and peptides/proteins are an inevitable component of the aging process in all eukaryotic organisms, including humans. To date, a substantial body of evidence shows that AGEs and their functionally compromised adducts are linked to and perhaps responsible for changes seen during aging and for the development of many age-related morbidities. However, much remains to be learned about the biology of AGE formation, causal nature of these associations, and whether new interventions might be developed that will prevent or reduce the negative impact of AGEs-related damage. To facilitate achieving these latter ends, we show how invertebrate models, notably Drosophila melanogaster and Caenorhabditis elegans, can be used to explore AGE-related pathways in depth and to identify and assess drugs that will mitigate against the detrimental effects of AGE-adduct development. 10.1016/j.cmet.2018.08.014
    Emerging role of advanced glycation-end products (AGEs) in the pathobiology of eye diseases. Kandarakis Stylianos A,Piperi Christina,Topouzis Fotis,Papavassiliou Athanasios G Progress in retinal and eye research Advanced glycation end products (AGEs) have been implicated in vision loss associated with macula degeneration, cataract formation, diabetic retinopathy and glaucoma. This pathogenic potential is mainly attributed to their accumulation in ocular tissues where they mediate aberrant crosslinking of extracellular matrix proteins and disruption of endothelial junctional complexes that affects cell permeability, mediates angiogenesis and breakdown of the inner blood-retinal barrier. Furthermore, AGEs severely affect cellular metabolism by disrupting ATP production, enhancing oxidative stress and modulating gene expression of anti-angiogenic and anti-inflammatory genes. Elucidation of AGE-induced mechanisms of action in different eye compartments will help in the understanding of the complex cellular and molecular processes associated with eye diseases. Several pharmaceutical agents with anti-glycating and anti-oxidant properties as well as AGE crosslink 'breakers' have been currently applied to eye diseases. The role of diet and the beneficial effects of certain nutriceuticals provide an alternative way to manage chronic visual disorders that affect the quality of life of millions of people. 10.1016/j.preteyeres.2014.05.002
    Transactivation of RAGE mediates angiotensin-induced inflammation and atherogenesis. Pickering Raelene J,Tikellis Christos,Rosado Carlos J,Tsorotes Despina,Dimitropoulos Alexandra,Smith Monique,Huet Olivier,Seeber Ruth M,Abhayawardana Rekhati,Johnstone Elizabeth Km,Golledge Jonathan,Wang Yutang,Jandeleit-Dahm Karin A,Cooper Mark E,Pfleger Kevin Dg,Thomas Merlin C The Journal of clinical investigation Activation of the type 1 angiotensin II receptor (AT1) triggers proinflammatory signaling through pathways independent of classical Gq signaling that regulate vascular homeostasis. Here, we report that the AT1 receptor preformed a heteromeric complex with the receptor for advanced glycation endproducts (RAGE). Activation of the AT1 receptor by angiotensin II (Ang II) triggered transactivation of the cytosolic tail of RAGE and NF-κB-driven proinflammatory gene expression independently of the liberation of RAGE ligands or the ligand-binding ectodomain of RAGE. The importance of this transactivation pathway was demonstrated by our finding that adverse proinflammatory signaling events induced by AT1 receptor activation were attenuated when RAGE was deleted or transactivation of its cytosolic tail was inhibited. At the same time, classical homeostatic Gq signaling pathways were unaffected by RAGE deletion or inhibition. These data position RAGE transactivation by the AT1 receptor as a target for vasculoprotective interventions. As proof of concept, we showed that treatment with the mutant RAGE peptide S391A-RAGE362-404 was able to inhibit transactivation of RAGE and attenuate Ang II-dependent inflammation and atherogenesis. Furthermore, treatment with WT RAGE362-404 restored Ang II-dependent atherogenesis in Ager/Apoe-KO mice, without restoring ligand-mediated signaling via RAGE, suggesting that the major effector of RAGE activation was its transactivation. 10.1172/JCI99987
    Targeting adaptor protein SLP76 of RAGE as a therapeutic approach for lethal sepsis. Yan Zhengzheng,Luo Haihua,Xie Bingyao,Tian Tian,Li Shan,Chen Zhixia,Liu Jinghua,Zhao Xuwen,Zhang Liyong,Deng Yongqiang,Billiar Timothy R,Jiang Yong Nature communications Accumulating evidence shows that RAGE has an important function in the pathogenesis of sepsis. However, the mechanisms by which RAGE transduces signals to downstream kinase cascades during septic shock are not clear. Here, we identify SLP76 as a binding partner for the cytosolic tail of RAGE both in vitro and in vivo and demonstrate that SLP76 binds RAGE through its sterile α motif (SAM) to mediate downstream signaling. Genetic deficiency of RAGE or SLP76 reduces AGE-induced phosphorylation of p38 MAPK, ERK1/2 and IKKα/β, as well as cytokine release. Delivery of the SAM domain into macrophages via the TAT cell-penetrating peptide blocks proinflammatory cytokine production. Furthermore, administration of TAT-SAM attenuates inflammatory cytokine release and tissue damage in mice subjected to cecal ligation and puncture (CLP) and protects these mice from the lethality of sepsis. These findings reveal an important function for SLP76 in RAGE-mediated pro-inflammatory signaling and shed light on the development of SLP76-targeted therapeutics for sepsis. 10.1038/s41467-020-20577-3