Elucidating the epigenetic regulation of extracellular matrix and virus-induced fibroblast activation

阐明细胞外基质和病毒诱导的成纤维细胞活化的表观遗传调控

• 批准号: 10572863
• 负责人: Jaye C Gardiner
• 金额: $ 12.5万
• 依托单位: RESEARCH INST OF FOX CHASE CAN CTR
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10572863
• 关键词: 2019-nCoV; ATAC-seq; Affect; Applied Skills; Bacterial Infections; Binding; Binding Proteins; Biological Markers; Categories; Cells; Cellular biology; ChIP-seq; Chemicals; Chromatin; Chronic Obstructive Pulmonary Disease; Communication; Complex; Connective Tissue; Coxsackie B Viruses; Cues; DNA-Directed RNA Polymerase; Data; Deposition; Development; Disease; Environment; Epigenetic Process; Excision; Extracellular Matrix; Failure; Fibroblasts; Fibrosis; Future; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Goals; Grant; Growth Factor; Hepatitis B Virus; Histone Acetylation; Human; In Vitro; Infection; Inflammatory Response; Influenza A virus; Knockout Mice; Lead; Link; Liver Fibrosis; Malignant Neoplasms; Mediating; Mesenchymal; Molecular; Myofibroblast; Nucleosomes; Organ; Organ failure; Pancreas; Pancreatitis; Pathologic; Patient Isolation; Phenotype; Play; Predisposition; Process; Pulmonary Fibrosis; Regulation; Reporting; Research; Resolution; Respiratory Tract Infections; Respiratory syncytial virus; Role; Signal Transduction; Simplexvirus; Specificity; Stimulus; Testing; Time; Tissue Sample; Tissues; Transcription Coactivator; Transcription Initiation; Transforming Growth Factor beta; Tropism; Viral; Virus; Virus Diseases; Work; brahma; chromatin remodeling; clinically relevant; cytokine; epigenetic memory; epigenetic regulation; experimental study; extracellular; falls; human pathogen; idiopathic pulmonary fibrosis; in vivo; innovation; insight; interstitial; memory acquisition; mouse model; netrin-G1; novel; pancreatic cancer patients; programs; recruit; repaired; response; skill acquisition; small molecule inhibitor; therapeutic target; tissue repair; transcriptome sequencing; virology; wound healing

PROJECT SUMMARY While wound healing processes are vital for successful organismal tissue repair, failure to turn off these mechanisms lead to the excessive accumulation of the extracellular matrix (ECM) and the development of fibrosis. Although recent research is beginning to illuminate the circumstances that allow for fibrosis resolution, most fibrotic conditions remain unresolved; resulting in organ failure or a predisposition to cancer. While the triggers for fibrotic diseases fall within a handful of categories, including viral/bacterial infection, tissue damage, and chemical insults, all induce the sustained activation of mesenchymal cells into myofibroblasts. Besides transforming growth factor β (TGF-β), which is a major activator of fibroblasts, the ECM also has the ability to alter a fibroblast’s activation state. We and others have demonstrated that this activated phenotype can persist despite the cell’s removal from fibrotic tissues, suggesting that fibroblasts have an “epigenetic memory” acquired during activation and retained thereafter. However, the molecular details underlying epigenetic regulation during myofibroblastic activation and whether these details are universal despite the activation trigger is unknown. One potential mechanism of myofibroblast regulation is through the ECM-dependent expression of pro- fibrotic genes. Gene expression is a tightly regulated process that requires chromatin remodeling, binding of transcriptional activators, and recruitment of RNA polymerase to initiate transcription. As such, the structural reorganization of the chromatin plays a large role in the temporal regulation and tissue specificity of gene expression. Brahma-related gene 1 (BRG1) is a central catalytic ATP-subunit of the BAF (BRG1/BRM1- associated factor) complex which works to drive chromatin accessibility via nucleosome eviction. BRG1 has also been shown to regulate ECM gene expression in both healthy and virally-induced fibrotic contexts. Moreover, preliminary data found that BRG1-deficient pancreatic fibroblasts lost the expression of a key functional regulator, Netrin G1. Taken together, this suggests a role of BRG1 in regulating myofibroblast pro-fibrotic genes. The overarching goal of this proposal is to test the hypothesis that the ECM and fibrosis-inducing viruses alter fibroblasts’ chromatin landscape in a BRG1-dependent manner and contribute to the epigenetic memory that underlies myofibroblastic function. To test this hypothesis, Aim 1 will first investigate BRG1’s involvement in pancreatic fibroblast activation in vitro and whether this is regulated by ECM-mediated signaling. In Aim 2, experiments will focus on the role of BRG1 in regulating disease formation by using an in vivo pancreatitis mouse model. Finally, Aim 3 will build on these lessons and investigate the mechanisms by which fibrosis-inducing viruses cause myofibroblast activation, beginning with the frequent human pathogen, Influenza A virus. By using a novel perspective to understanding fibrosis, this research provides insights that will advance cell biology, epigenetics, and virology, as well as reveal how the ECM/viruses create a pro-fibrotic state.

项目概要 虽然伤口愈合过程对于成功的有机组织修复至关重要，但未能关闭这些过程 机制导致细胞外基质（ECM）过度积累并发展 纤维化。尽管最近的研究开始阐明纤维化消退的环境， 大多数纤维化病症仍未得到解决；导致器官衰竭或易患癌症。虽然 纤维化疾病的诱因分为几类，包括病毒/细菌感染、组织损伤、 和化学损伤，都会诱导间充质细胞持续活化为肌成纤维细胞。除了 转化生长因子 β (TGF-β) 是成纤维细胞的主要激活剂，ECM 还能够 改变成纤维细胞的激活状态。我们和其他人已经证明这种激活的表型可以持续存在 尽管细胞从纤维化组织中去除，这表明成纤维细胞具有获得的“表观遗传记忆” 激活期间并在激活后保留。然而，表观遗传调控的分子细节 肌成纤维细胞激活以及尽管激活触发因素这些细节是否具有普遍性尚不清楚。 肌成纤维细胞调节的一种潜在机制是通过 ECM 依赖性表达 纤维化基因。基因表达是一个严格调控的过程，需要染色质重塑、结合 转录激活剂，以及招募 RNA 聚合酶来启动转录。因此，结构 染色质重组在基因的时间调控和组织特异性中发挥着重要作用 表达。 Brahma 相关基因 1 (BRG1) 是 BAF 的中心催化 ATP 亚基 (BRG1/BRM1- 相关因子）复合物，通过核小体驱逐来驱动染色质可及性。 BRG1也有 已被证明可以在健康和病毒诱导的纤维化环境中调节 ECM 基因表达。而且， 初步数据发现，BRG1缺陷的胰腺成纤维细胞失去了关键功能的表达 调节剂，Netrin G1。综上所述，这表明 BRG1 在调节肌成纤维细胞促纤维化基因中发挥作用。 该提案的总体目标是检验 ECM 和纤维化诱导病毒改变的假设 以 BRG1 依赖性方式改变成纤维细胞的染色质景观，并有助于表观遗传记忆 是肌成纤维细胞功能的基础。 为了检验这一假设，目标 1 将首先研究 BRG1 在胰腺成纤维细胞激活中的作用 体外以及这是否受到 ECM 介导的信号传导的调节。在目标 2 中，实验将重点关注 BRG1 通过体内胰腺炎小鼠模型调节疾病形成。最后，Aim 3 将建立在 这些教训并研究纤维化诱导病毒引起肌成纤维细胞激活的机制， 首先是常见的人类病原体甲型流感病毒。通过使用新颖的视角来理解 纤维化，这项研究提供了一些见解，将推动细胞生物学、表观遗传学和病毒学的发展，并揭示 ECM/病毒如何产生促纤维化状态。