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Pathogenesis of NASH Cirrhosis

NASH 肝硬化的发病机制

基本信息

批准号：
9131857
负责人：
ANNA MAE ELIZABETH DIEHL
金额：
$ 27.83万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-09-15 至 2016-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9131857
关键词：
Adherens Junction Area Automobile Driving Back Cell Nucleus Cells Cirrhosis Coculture Techniques Data Disease Duct (organ) structure Early Diagnosis Epidemic Erinaceidae Fibrosis Gene Expression Gene Targeting Goals Growth Growth Factor Health Hepatic Stellate Cell Human Knockout Mice Knowledge Life Ligands Liver Liver Fibrosis Liver Regeneration Mediating Modeling Molecular Target Morbidity - disease rate Mus Myofibroblast Natural regeneration Nuclear Pathogenesis Pathway interactions Patients Peptide Signal Sequences Peptides Phenotype Phosphoric Monoester Hydrolases Phosphorylation Phosphotransferases Prevention Production Proteins Reaction Recovery Regulation Research Rodent Severities Signal Transduction Work base feeding fibrogenesis human PTPRT protein improved inhibitor/antagonist injured insight liver injury mortality new therapeutic target nonalcoholic steatohepatitis novel novel diagnostics novel therapeutic intervention pleiotrophin prevent programs receptor repaired smoothened signaling pathway stellate cell success transcription factor

项目摘要

DESCRIPTION (provided by applicant): Cirrhosis caused by nonalcoholic steatohepatitis (NASH) is common and life threatening. Gaps in knowledge about myofibroblasts, the fibrogenic cells that drive cirrhosis pathogenesis styme treatment of NASH-cirrhosis. In NASH-cirrhosis, myofibroblasts derive from resident stellate cells. We discovered that: 1) stellate cells must induce and maintain Hedgehog signaling to be myofibroblastic, 2) persistent Hedgehog activity causes progressive fibrosis, and 3) transient Hedgehog activation is necessary for liver regeneration. Hedgehog must be induced, and then suppressed, for recovery from NASH. Identifying the mechanisms which regulate Hedgehog signaling is imperative for defining novel therapeutic targets to reverse hepatic fibrosis. Herein, we evaluate a novel HYPOTHESIS that interaction of pleiotrophin (a myofibroblast-derived factor that promotes regeneration) and its receptor, protein tyrosine phosphatase receptor zeta-1 (PTPRZ1), prevents NASH- cirrhosis by antagonizing Hedgehog's pro-fibrogenic actions in myofibroblasts. Recently, we discovered that "degregulation" of pleiotrophin-Hedgehog signaling in PTPRZ1-expressing stellate cells might contribute to cirrhosis pathogenesis in NASH. Specifically, we found that livers with NASH are enriched with PTPRZ1(+) cells and showed that pleiotrophin antagonizes key actions of Hedgehog by studying pleiotrophin- and PTPRZ1-knockout mice. Studies in cultured stellate cells indicated that the mechanism is indirect and involves pleiotrophin-dependent inhibition of PTPRZ1's phosphatase activity, alteration of the phosphoproteome, and consequent changes in the cellular localization of Yes-activated peptide (YAP), a Hippo kinase-regulated transcriptional co-activator that controls liver growth. We propose a novel paradigm whereby myofibroblast fate is controlled by factors, such as Hedgehog and pleiotrophin, that modulate activation/inactivation of YAP. Our SPECIFIC AIMS are to: 1) determine how pleiotrophin inhibits Hedgehog activity in myofibroblasts and 2) determine how pleiotrophin-mediated inhibition of Hedgehog in myofibroblasts inhibits NASH cirrhosis. Successful completion of this proposal will identify new therapeutic targets for NASH cirrhosis and fill a gap in knowledge about the regulation of fibrotic liver injury.