THE RELAXIN RECEPTOR GR/RXFP1 SIGNALING IN LIVER TRANSPLANT ISCHEMIA-REPERFUSION INJURY AND THE INFLAMMATION RESOLUTION

松弛素受体 GR/RXFP1 信号在肝移植缺血再灌注损伤和炎症消退中的作用

• 批准号: 10268216
• 负责人: Jerzy W Kupiec-Weglinski
• 金额: $ 39万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-22 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10268216
• 关键词: Acute; Affect; Agonist; Anti-Inflammatory Agents; Antiinflammatory Effect; Attenuated; Autophagocytosis; Binding; Biological; Cell physiology; Cells; Chronic; Clinical; Epidemic; Formulation; Genes; Glucocorticoid Receptor; Glucocorticoids; Goals; Gold; Heart failure; Hepatic; Hepatic Tissue; Hepatocyte; Hepatology; Homeostasis; Human; Immune; Inflammation; Inflammatory; Intervention; Knock-in Mouse; Link; Liver; Liver Fibrosis; Liver diseases; Liver neoplasms; Macrophage Activation; Molecular; Mus; Organ; Organ Donor; Organ Transplantation; Outcome; Pathology; Pathway interactions; Patients; Perfusion; Pharmacology; Phase; Phase III Clinical Trials; Phenotype; Pilot Projects; Primary carcinoma of the liver cells; Property; Publishing; Receptor Signaling; Recombinants; Regulation; Rejuvenation; Relaxin; Reperfusion Injury; Resistance; Resolution; Role; SIRT1 gene; Severities; Signal Transduction; Solid; Somatomedins; Stress; System; T-Lymphocyte; Testing; Tissues; Transplant Recipients; Transplantation; alternative treatment; chronic liver disease; editorial; experimental study; glucocorticoid-induced orphan receptor; immunoregulation; improved; innovation; insight; liver ischemia; liver transplantation; macrophage; mimetics; non-alcoholic fatty liver disease; nonalcoholic steatohepatitis; novel; peptide hormone; preservation; prevent; receptor; regeneration function; relating to nervous system; relaxin receptor; response; side effect; small molecule; standard of care; success; tissue injury; tool; transplant model

PROJECT SUMMARY/ABSTRACT Hepatic ischemia/reperfusion injury (IRI), an innate immune-driven inflammation response, is a major obstacle limiting the success of orthotopic liver transplantation (OLT) in patients with end-stage liver disease and those with tumors of hepatic origin. Although significant progress has been made in better appreciation of the liver inflammatory cascade by IR-stress, much less is known about its resolution, which may affect not only the severity of tissue injury itself but also, more importantly, the long-term outcomes. Recent studies document striking cytoprotective functions of hrRLX (recombinant human relaxin-2) against IR-stress in mouse OLT models via hepatocyte glucocorticoid receptor (GR) signaling; while polarizing macrophage activation via Notch1 promoted IRI-OLT resistance. These experimental findings, supported by a clinical evidence of enhanced GR/Notch1 phenotype needed for IRI resistance in human OLT, prompted to propose that rhRLX may function as a novel GR agonist and glucocorticoid (GC) mimetic in liver transplantation. Pilot studies also point to anti- fibrotic functions of the cognate RXFP1 receptor, a GR-independent RLX-2 binding partner. As the conventional murine OLT model offers a limited translational utility, this project will be dissecting GR – RXFP1 molecular interplay in mice expressing human RXFP1 gene; as well as testing new concepts of RXFP1-driven hepatic rejuvenation of discarded human livers during hypothermic machine preservation. A newly discovered divergent role of GR–RXFP1 signaling axis in the “acute” and “resolution” phase of IRI-OLT inflammation, has prompted to put forth a novel and heretofore untested overall hypothesis, that: 1/ pharmacological rhRLX-induced GR enhancement will rescue OLT from acute IR-insult; while 2/ harnessing GR-independent rhRLX signaling via its cognate receptor, RXFP1, will promote homeostatic/anti-fibrotic functions in the inflammation resolution phase. Two interlocked aims explore this hypothesis: Aim 1: Delineate molecular mechanisms of rhRLX – GR hepatocellular protection in OLT (acute IRI-inflammation phase). Aim 1.1: Test hypothesis that hepatocellular Keap1-dependent Nrf2 signaling is indispensable for rhRLX – GR axis to prevent DAMPs release and innate inflammation in cold-stored donor livers. Aim 1.2: Test hypothesis that SIRT1 enhances GR-induced hepatocyte regenerative functions/autophagy in IR-stressed OLT. Aim 2. Delineate molecular mechanisms of Notch1 / RXFP1 anti-fibrotic functions in OLT (IRI-inflammation “resolution” phase). Aim 2.1: Test hypothesis that Notch1 (macrophage) – RXFP1 (T cell) cross-regulation is essential in the resolution of IRI – OLT inflammation. Aim 2.2: Test hypothesis that the activation of human RLX receptor exerts anti-fibrotic functions in the resolution of IRI-OLT inflammation in humanized RXFP1 “knockin” mouse system. Aim 2.3: Test hypothesis that activation of RXFP1 receptor during hypothermic machine preservation attenuates inflammation and rejuvenates discarded human donor livers.

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