Hepatic stellate cell plasticity and maladaptive fibrogenic memory in chronic liver disease

慢性肝病中的肝星细胞可塑性和适应不良纤维化记忆

• 批准号: 10638234
• 负责人: Shuang Wang
• 金额: $ 59.22万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2028-02-29
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10638234
• 关键词: Acute; Affect; Animal Model; Automobile Driving; Behavior; Cells; Cellular biology; Chromatin; DNA; DNA Methylation; Development; Epigenetic Process; Exposure to; Extracellular Matrix; Fibrosis; Gene Expression; Genes; Genetic Transcription; Genomics; Hepatic Stellate Cell; Injury; Liver; Liver Fibrosis; Liver diseases; LoxP-flanked allele; Measures; Memory; Modeling; Molecular; Mus; Paper; Patients; Regulatory Element; Research; Technology; WT1 gene; acute liver injury; chronic liver disease; chronic liver injury; epigenome; epigenomics; in vivo; innovation; insight; liver injury; maladaptive behavior; member; methylation pattern; methylome; mortality; mouse model; novel; response; single cell technology; stellate cell; therapeutic target; tissue injury; tissue repair; transcriptome

PROJECT SUMMARY Hepatic stellate cell plasticity and maladaptive fibrogenic memory in chronic liver disease Fibrosis associated with chronic liver disease affects hundreds of millions of patients worldwide. Hepatic stellate cells (HSCs), in turn, represent the main cellular driver of hepatic fibrosis. A key unanswered question is why HSCs activate to facilitate tissue repair in response to acute liver injury but hyperactivate to produce exuberant extracellular matrix in response to repeated liver injury, leading to fibrosis. Central to this behavior switch is a mechanism for HSCs to remember previous injury episodes in order to respond differently, i.e. hyperactivate, when exposed to re-injury. Recent studies, including ours (Wang et al. Dev Cell 2019), strongly support the epigenome and in particular DNA methylation patterns as the carrier of cell memory in development and in tissue injury. The objective of this research is to clarify how the epigenome and specifically DNA methylation patterns encode this maladaptive cell memory and amplify HSC’s fibrogenic response following re-injury. This proposal builds upon recent advances in single cell technology and low-input chromatin profiling which we optimized extensively to measure HSC gene expression and epigenomic changes in vivo in a novel mouse model of fibrogenic memory. In our fibrogenic memory model, HSCs completely deactivate following fibrosis regression, with their transcriptome indistinguishable from uninjured HSCs, however epigenomic changes persist in the form of chromatin accessibility changes. In response to re-injury, HSCs from regressed liver hyperactivate and are driven by unique transcriptional networks (WT1, TEAD1, TBX20, and PBX1) not found in HSCs undergoing initial injury. Using the Uhrf1 floxed mice generated previously in our Dev Cell paper to specifically remove Uhrf1, a critical component of the DNA methylation machinery, in HSCs, we found that these mice display augmented fibrogenic memory in response to re-injury. Our central hypothesis is that memory of previous injury through epigenetic changes modify HSC plasticity and amplify their activation in response to re-injury. We will address this hypothesis in three interrelated, but distinct specific aims:1) Define the regulatory elements controlling fibrogenic memory in HSCs; 2) Determine how UHRF1 and the DNA methylome control fibrogenic memory in HSCs; 3) Uncover novel regulatory nodes driving HSC’s maladaptive response in re-injury. This innovative approach leveraging cutting-edge genomics technology and unique animal models is significant because it will yield fundamental new insights into stellate cell biology by uncovering the epigenetic basis of fibrogenic memory, the contribution of specific genes and transcriptional networks to fibrogenic memory and hepatic fibrosis, and conserved fibrogenic drivers in liver disease patients that can lead to potential therapeutic targets.

项目概要 慢性肝病中的肝星细胞可塑性和适应不良纤维化记忆 与慢性肝病相关的纤维化影响着全世界数亿患者。 反过来，肝细胞（HSC）代表了肝纤维化的主要细胞驱动因素，一个尚未解答的关键问题是为什么。 HSC 会激活以促进组织修复以应对急性肝损伤，但会过度激活以产生旺盛的 细胞外基质对反复肝损伤的反应，导致纤维化，这种行为转换的核心是一个。 HSC 记住以前的损伤事件以便做出不同反应的机制，即过度激活， 最近的研究，包括我们的研究（Wang et al. Dev Cell 2019），强烈支持 表观基因组，特别是 DNA 甲基化模式作为发育和组织中细胞记忆的载体 本研究的目的是阐明表观基因组，特别是 DNA 甲基化模式。 编码这种适应不良的细胞记忆并放大 HSC 在再次受伤后的纤维化反应。 基于单细胞技术和低输入染色质分析的最新进展，我们对其进行了优化 在新型小鼠模型中广泛测量 HSC 基因表达和体内表观基因组变化 在我们的纤维化记忆模型中，HSC 在纤维化消退后完全失活， 它们的转录组与未受损的 HSC 无法区分，但表观基因组变化以这种形式持续存在 为了应对再次损伤，来自退化肝脏的 HSC 过度激活并发生变化。 由独特的转录网络（WT1、TEAD1、TBX20 和 PBX1）驱动，在进行初始转录的 HSC 中未发现 使用我们之前在 Dev Cell 论文中生成的 Uhrf1 floxed 小鼠来特异性去除 Uhrf1，这是一种 DNA 甲基化机制的关键组成部分，在 HSC 中，我们发现这些小鼠表现出增强的 纤维化记忆对再次受伤的反应我们的中心假设是通过对先前受伤的记忆。 表观遗传变化会改变 HSC 的可塑性并增强其响应再次损伤的活性。 该假设有三个相互关联但又不同的具体目标：1）定义控制的监管要素 HSC 中的纤维化记忆；2) 确定 UHRF1 和 DNA 甲基化如何控制 HSC 中的纤维化记忆 HSC；3) 发现导致 HSC 再次损伤的适应不良反应的新调控节点。 利用尖端基因组学技术和独特的动物模型的方法具有重要意义，因为它将 通过揭示纤维化记忆的表观遗传基础，对星状细胞生物学产生基本的新见解， 特定基因和转录网络对纤维化记忆和肝纤维化的贡献，以及 肝病患者中保守的纤维形成驱动因素可以导致潜在的治疗靶点。