权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Inactivation of Hepatic Stellate Cells During Reversal of Liver Fibrosis

肝纤维化逆转过程中肝星状细胞失活

基本信息

批准号：
9271180
负责人：
Tatiana Kisseleva
金额：
$ 33.71万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-05-15 至 2019-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9271180
关键词：
Acetylation Adult Affect Binding Sites Biochemical Biology Cell model Cells ChIP-seq Chronic Cirrhosis Collagen Collagen Type I DNA Binding Data Deposition Detection Development Epigenetic Process Event Extracellular Matrix Proteins Flow Cytometry Gene Activation Gene Chips Gene Expression Gene Expression Profile Gene Targeting Genes Genetic Transcription Goals Healthcare Hepatic Stellate Cell Hepatotoxicity Human Human Genome In Vitro Injury to Liver Investigation Knockout Mice Label Link Liver Liver Fibrosis Liver diseases Location LoxP-flanked allele Maintenance Mediating Messenger RNA Molecular Mus Myofibroblast PPAR gamma Pathway interactions Patients Phenotype Population Production Recovery Regulation Regulator Genes Repression Reverse Transcriptase Polymerase Chain Reaction Role Signal Transduction Site Small Interfering RNA Source Stimulus System TIMP1 gene Tamoxifen Testing Time Translating Transplantation Up-Regulation base blocking factor care burden genome wide methylation genome-wide histone modification in vitro testing in vivo injured insight interest intrahepatic knock-down liver injury mRNA Expression mouse genome mouse model novel overexpression prevent public health relevance pup response therapeutic target transcription factor transcriptome sequencing

项目摘要

DESCRIPTION (provided by applicant): Chronic liver injury results in hepatic fibrosis, in which quiescent hepatic stellate cells (qHSCs) activate into myofibroblasts, depositing extensive extracellular matrix (ECM) proteins. Cessation of fibrogenic stimuli often results in regression of liver fibrosis and is associated with the disappearance of activated HSCs (aHSCs)/myofibroblasts. We have recently demonstrated that some aHSCs apoptose, while other aHSCs inactivate (iHSCs) into a quiescent-like phenotype. The overall goals of this Project are to identify the molecular factors that may prevent HSC activation into myofibroblasts, or that revert aHSC into an inactivated state. Our central hypothesis is that genome wide epigenetic changes regulate HSC phenotype by activation (or suppression) of transcriptional activity in HSCs. We also hypothesize that activation of PPARγ-target genes regulates quiescent and inactivated HSC phenotypes. AIM1: We will assess the genome wide methylation and acetylation sites using ChIP-Seq in qHSCs, aHSCs and iHSCs in order to identify motifs and transcription factors critical for HSC inactivation. Using in vitro systems, we will determine f siRNA knock-down or overexpression of these factors blocks HSC activation, or triggers HSC inactivation. AIM2: We have demonstrated that PPARγ is re-expressed in HSCs during inactivation. To gain a greater insight into the mechanisms of HSC inactivation, we will conduct a broad investigation of the epigenetic changes that regulate PPARγ-target genes in distinct HSC phenotypes (qHSCs, aHSCs and iHSCs). We will test if functional inhibition of these genes affects the qHSC and iHSC phenotypes. AIM3: We will assess the role of PPARγ and PPARγ target genes in HSC biology in vivo using knockout mice, in which PPARγ is constitutively or inducibly deleted specifically in HSCs. A specific role of PPARγ in the maintenance of quiescent HSC phenotype and inactivation of aHSCs will be assessed in PPARγ-deficient HSCs versus wild type HSCs. We anticipate that the collective results obtained in AIMs 1-3 will identify specific factors that can revert aHSCs into an inactivated quiescent-like state. AIM4: Our findings in mice must be translated to patients with fibrotic liver disease. To examine how human HSCs inactivate, quiescent human HSCs will be engrafted into livers of Rag2-/-γc-/- mice, and their activation will be induced in vivo by CCl4 followed by recovery. Human qHSCs, aHSCs and iHSCs will be isolated at each time point and analyzed by RT-PCR, Human genome microarray and flow cytometry. Next, human iHSCs will be subjected to ChIP-Seq analysis, and inactivation-specific targets will be identified (and compared to that in mouse iHSCs). The ability of these targets to inactivate human aHSCs into a quiescent-like state will be tested in vitro and in vivo using siRNA knock-down or intrahepatic transplantation of human HSCs into Rag2-/-γc-/- mice. The results of our studies will give new insight into mechanisms underlying HSC inactivation in mice and patients, identifying potential therapeutic targets that can induce inactivation of activated HSCs/myofibroblasts in fibrotic liver.

描述（由申请人提供）：慢性肝损伤导致肝纤维化，其中静止的肝星状细胞（qhsc）激活成肌成纤维细胞，沉积大量细胞外基质（ECM）蛋白。停止纤维原性刺激通常会导致退化