Molecular Mechanisms of Liver Fibrosis

肝纤维化的分子机制

• 批准号: 10407227
• 负责人: VIJAY H. SHAH
• 金额: $ 35.78万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2027-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10407227
• 关键词: Alcohol consumption; Alcohols; Attenuated; Binding; Binding Proteins; Biological Assay; Cellular biology; Cirrhosis; Clustered Regularly Interspaced Short Palindromic Repeats; Data; Deposition; Development; EZH2 gene; Endosomes; Enhancers; Epigenetic Process; Etiology; Fibrosis; Gene Activation; Gene Expression; Gene Expression Regulation; Genes; Genetic; Genetic Transcription; Goals; Growth Factor; Hepatic Stellate Cell; Hi-C; Histones; Human; IGFBP3 gene; Image; In Vitro; Instruction; Insulin; Investigation; Knock-out; Lead; Liver; Liver Fibrosis; Lobule; Magnetic Resonance Elastography; Mediating; Modeling; Modification; Molecular; Morbidity - disease rate; Mus; Peptides; Platelet-Derived Growth Factor; Platelet-Derived Growth Factor alpha Receptor; Play; Population; Portal vein structure; Process; Production; Proteins; Receptor Protein-Tyrosine Kinases; Receptor Signaling; Role; Signal Transduction; Signaling Protein; Techniques; Testing; Transferase; Transforming Growth Factor beta; Vesicle; cell motility; chromatin modification; epigenetic regulation; fibrogenesis; gene network; histone methylation; histone methyltransferase; in vivo; innovation; knock-down; liver injury; migration; mortality; mouse model; novel; parent grant; promoter; protein transport; recruit; single-cell RNA sequencing; therapeutic target; trafficking; transcriptome sequencing

Hepatic stellate cell (HSC) activation encompasses aphenotype that includes enhanced migration, proliferation, and matrix deposition. Migration is critical for coordinately situating HSC for matrix deposition and development of cirrhosis. Our Long-Term Objectives are to understand the molecular underpinnings of HSC biology that lead to cirrhosis with the goal of identifying therapeutic targets. Recently,we identified a critical role of synectin in the process of HSC migration and fibrosis. Synectin is a cytosolic protein that mediates signal transduction, vesicle trafficking, and ultimately gene expression. Synectin is chosen for this proposal as a significant protein warranting detailed investigation because, as we demonstrate, it is upregulated in human cirrhosis and is required for murine fibrogenesis. Mechanistically, we implicate synectin inHSC migration through both short term receptor signaling as well as longer term epigenetic regulation of gene expression networks. Our preliminary data show that depletion of HSC synectin reduces migration signaling downstream of the receptor tyrosine kinase, platelet derived growth factor receptor alpha (PDGFRα); attenuates transcription of a set of HSC activation genes including one that encodes the multifunctional signaling protein, IGFBP3 (insulin growth factor binding protein-3); and abrogates murine fibrosis in vivo. These important observations have led us to propose the central hypothesis that synectin increases HSC migration and fibrosis by promoting PDGFRα signaling and by regulating a network of genes that include IGFBP3. This hypothesis leads to the following Specific Aims: 1) Synectin promotes HSC migration by regulating PDGFRα targeting and signal activation. Aim 1a will determine how synectin recruits and binds specific vesicle trafficking proteins that maintain PDGFRα protein levels, target the protein to endosomes and activate migration signaling. Aim 1b will uncover how disruption of synectin function leads to autophagic degradation of PDGFRα and attenuated HSC migration. 2) Synectin epigenetically controls IGFBP3 gene expression to promote HSC migration. Aim 2a will identify how synectin regulates a specific histone methyl transferase, EZH2 and how this governs IGFBP3 gene expressionthrough histone methylation. Aim 2b will determine how IGFBP3 production stimulates HSC migration. 3) Synectin regulates fibrosis in vivo. Aim 3a will use a novel fibrosis regression model in mice with HSC selective modifications to synectin and PDGFRα to further ascertain the proposed role of these proteins in vivo. Aim 3b will use a synectin neutralizing peptide that selectively targets HSC in coordination with magnetic resonance elastography (MRE) imaging, and mice with genetic deletion of IGFBP3 to elucidate how synectin promotes fibrosis in vivo. In total, this proposal will utilize conceptually and technically innovative approaches and concepts to test a novel hypothesis pertaining to synectin as a “master regulator” of HSC signals that lead to migration and fibrosis. RELEVANCE (See instructions): Liver injury from alcohol and other etiologies can culminate in cirrhosis with significant associated morbidity and mortality.

肝星状细胞(HSC)的激活包括表型，包括促进迁移， 增殖和基质沉积。迁移是协调放置HSC以进行基质沉积的关键 和肝硬变的发展。我们的长期目标是了解 导致肝硬变的HSC生物学，目的是确定治疗靶点。最近，我们发现了一个 粘附素在HSC迁移和纤维化过程中的关键作用。聚合素是一种胞质蛋白， 介导信号转导，囊泡运输，最终基因表达。赛诺克汀就是为此被选中的 作为一种重要的蛋白质，需要进行详细的研究，因为正如我们所证明的，它是 在人类肝硬变中上调，是小鼠纤维化所必需的。从机制上讲，我们认为联结 通过短期受体信号转导和长期表观遗传调控的HSC迁移 基因表达网络。我们的初步数据显示，HSC连接素的耗尽减少了迁移 受体酪氨酸激酶的下游信号，血小板衍生生长因子受体α (PDGFRα)；减弱一组肝星状细胞激活基因的转录，包括编码 多功能信号蛋白IGFBP3(胰岛素生长因子结合蛋白-3)； 体内纤维化。这些重要的观察结果使我们提出了联结蛋白的中心假说 通过促进血小板衍生生长因子受体α信号转导和调节基因网络促进造血干细胞迁移和纤维化 这包括IGFBP3。这一假说的具体目的如下：1)聚合素促进肝星状细胞 通过调节PDGFRα靶向和信号激活进行迁移。Aim 1a将决定Sycertin如何招募员工 并结合特定的囊泡运输蛋白，维持PDGFRα蛋白水平，靶向该蛋白 内体和激活迁移信号。目标1b将揭示连接蛋白功能中断是如何导致 血小板衍生生长因子受体α的自噬降解和减弱的造血干细胞迁移。2)聚合素表观遗传调控 IGFBP3基因表达促进HSC迁移。目标2a将确定联结蛋白如何调节特定的 组蛋白甲基转移酶EZH2及其通过组蛋白调控IGFBP3基因表达的研究 甲基化。Aim 2b将确定IGFBP3的产生如何刺激HSC迁移。3)聚合素调节 体内纤维化。Aim 3a将在HSC选择性修饰的小鼠中使用一种新的纤维化回归模型 以进一步确定这些蛋白在体内的拟议作用。Aim 3b将使用 结合核磁共振选择性靶向HSC的粘附素中和肽 弹性成像(MRE)成像，以及IGFBP3基因缺失的小鼠以阐明连接蛋白如何促进 体内纤维化。总而言之，这项提案将利用概念和技术上的创新方法和 测试一种新的假说的概念，该假说认为联结蛋白是HSC信号的“主调节器”，导致 迁移和纤维化。 相关性(请参阅说明)： 酒精和其他原因造成的肝损伤可最终导致肝硬变，并伴有显著的相关发病率。 和死亡率。