Identifying targetable mechanisms of TMEM38B/TRIC-B in liver fibrosis

鉴定 TMEM38B/TRIC-B 在肝纤维化中的靶向机制

• 批准号: 10216441
• 负责人: Jessica L Maiers
• 金额: $ 15.85万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-15 至 2022-05-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10216441
• 关键词: Apoptosis; Area; C-terminal; Cations; Cell Survival; Cells; Cicatrix; Cirrhosis; Clinic; Collagen; Collagen Type I; Communities; Complex; Cytoplasmic Tail; Data; Deposition; Endoplasmic Reticulum; Engineering; Enhancers; Extracellular Matrix; Fibrosis; Genes; Genome; Goals; Hepatic Stellate Cell; Hepatocyte; Human; Impairment; In Vitro; Ion Channel; Liver; Liver Failure; Liver Fibrosis; Mediating; Methyltransferase; Mission; Morphology; Mus; Mutate; Mutation; Nucleic Acid Regulatory Sequences; Osteoblasts; Osteogenesis Imperfecta; Pathologic; Pathway interactions; Patients; Pharmaceutical Preparations; Pharmacology; Physiological; Polycomb; Post-Translational Protein Processing; Post-Translational Regulation; Process; Procollagen; Production; Proteins; Reagent; Regulation; Repressor Proteins; Research; Role; Site-Directed Mutagenesis; Stimulus; System; Tissues; Transforming Growth Factor beta; Up-Regulation; Viral Vector; bone; chronic liver injury; cytokine; endoplasmic reticulum stress; experimental study; fibrogenesis; global health; histone methyltransferase; in vivo; insight; liver injury; liver transplantation; mouse model; mutant; novel; novel therapeutic intervention; prevent; protein transport; response; single-cell RNA sequencing; trafficking

ABSTRACT: Liver fibrosis impacts millions of people globally, with no pharmacologic therapies available to limit fibrosis progression or promote fibrosis regression. The major fibrogenic cells in the liver are Hepatic Stellate Cells (HSCs). Upon liver injury, activated HSCs produce and secrete fibrogenic proteins, including collagen Iα1 and 1α2, which are major component of fibrotic scarring in the liver. Several therapies have aimed to target HSCs to limit fibrogenesis by preventing HSC activation or promoting HSC apoptosis; however these strategies have not been successful in the clinic. We propose that understand the procollagen I trafficking machinery would provide a unique and viable strategy for limiting fibrosis. We performed single cell RNA sequencing on fibrogenic HSCs from mice and found upregulation of the understudied gene TMEM38B in fibrogenic HSCs. TMEM38B is implicated in procollagen I trafficking in bone-producing osteoblasts, and mutations in TMEM38B leads to brittle bones in mice and humans. We hypothesize that TMEM38B is critical for fibrogenesis through mediating procollagen I trafficking and HSC survival, and that targeting TMEM38B could serve as a viable anti- fibrotic strategy. Our preliminary data highlights a key role for TMEM38B in fibrogenesis. TMEM38B expression is increased in patients where liver fibrosis has progressed to cirrhosis, as well as in murine models of liver fibrosis. Secondly, TMEM38B is increased in primary human and mouse HSCs following activation with the pro-fibrotic cytokine TGFβ. Finally, we show that TMEM38B is negatively regulated by the Polycomb Repressor Complex 2 (PRC), a histone methyltransferase complex dysregulated in fibrosis. Disruption of the PRC2 complex leads to increased TMEM38B expression in HSCs, and increased procollagen I deposition in a murine model where key components of the PRC2 complex are deleted from osteoblasts. The experiments proposed here will increase our understanding of TMEM38B in 3 critical areas: 1) Elucidating the critical contribution of TMEM38B to fibrogenic processes, including procollagen I secretion and HSC survival, 2) interrogating the critical domains and post-translational regulation of TMEM38B channel activity, and 3) revealing mechanisms that regulate TMEM38B expression. Completion of the proposed research will provide crucial insight into TMEM38B function and regulation under both physiological and pathophysiological conditions as well as provide novel reagents to share with the research community, with the long term goal of targeting TMEM38B as an anti-fibrotic strategy.

抽象的： 肝纤维化会影响全球数百万的人，没有可限制纤维化的药理疗法 进展或促进纤维化消退。肝脏中的主要纤维化细胞是肝星状细胞 （HSC）。肝损伤后，活化的HSC产生和秘密纤维蛋白，包括胶原蛋白Iα1和 1α2，是肝脏纤维化疤痕的主要成分。几种旨在针对HSC的疗法 通过防止HSC激活或促进HSC凋亡来限制纤维发生；但是这些策略有 在诊所没有成功。我们建议了解我贩运机械的Procolagen 为限制纤维化提供了独特而可行的策略。我们在 来自小鼠的纤维化HSC，并在纤维元素HSC中发现了知识的基因TMEM38B的上调。 TMEM38B在产生骨成骨细胞中的procollagen I运输中暗示，TMEM38B中的突变 导致老鼠和人类的骨骼脆弱。我们假设TMEM38B对于通过 介导procollagen I运输和HSC生存，靶向TMEM38B可以作为可行的反抗 纤维化策略。我们的初步数据突出了TMEM38B在纤维发生中的关键作用。 TMEM38B表达 肝纤维化已发展为肝硬化的患者以及肝脏模型的患者增加 纤维化。其次，在激活后，原代人和小鼠HSC中TMEM38B增加了 促纤维化细胞因子TGFβ。最后，我们表明TMEM38B受多孔负面调节 抑制剂复合物2（PRC），一种组蛋白甲基转移酶复合物在纤维化中失调。破坏 PRC2复合物导致HSC中TMEM38B表达增加，并增加了procollagen I沉积在A中 鼠模型中，PRC2复合物的关键成分被从成骨细胞中删除。实验 这里提出的将在3个关键领域增加我们对TMEM38B的理解：1）阐明关键 TMEM38B对纤维化过程的贡献，包括Procollagen I分泌和HSC存活，2） 询问TMEM38B通道活动的关键域和翻译后调节，3） 揭示调节TMEM38b表达的机制。拟议研究的完成将提供 在生理和病理生理学下，对TMEM38B功能和调节的关键见解 条件以及提供与研究界共享的新颖试剂，其长期目标的 以抗纤维化策略为目标。