Role of STING in Cholestatic Liver Injury

STING 在胆汁淤积性肝损伤中的作用

基本信息

批准号：
10637131
负责人：
Burcin Ekser
金额：
$ 50.19万
依托单位：
TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-04-01 至 2027-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10637131
关键词：
Acceleration Adipocytes Adipose tissue Bile Acids Biliary Cells Cholestasis Chronic Clinical Critical Pathways Cyclic GMP Data Development Disease Endothelial Cells Fibrosis Gene Activation Gene Expression Gene Expression Regulation Hepatic Stellate Cell Hepatobiliary Hepatocyte Human Immune Inflammation Inflammatory Injury Knowledge Kupffer Cells Link Liver Liver Fibrosis Liver diseases Macrophage Macrophage Activation Mediator Mitochondria Mitochondrial DNA Molecular Mus Myeloid Cells Natural Immunity Organoids Oxidative Stress Pathogenesis Pathology Pathway interactions Patients Phenotype Play Proliferating Reaction Research Role Secretin Signal Transduction Signaling Protein Stimulator of Interferon Genes Testing Therapeutic Transforming Growth Factor beta autocrine cell type cholangiocyte design ds-DNA experimental study extracellular vesicles innovation insight liver inflammation liver injury mouse model non-alcoholic fatty liver disease novel novel strategies novel therapeutic intervention paracrine primary sclerosing cholangitis response senescence validation studies

项目摘要

Biliary liver diseases, such as primary sclerosing cholangitis (PSC), are characterized by the damage and proliferation of cholangiocytes that are a key link between biliary injury and the subepithelial fibrosis, manifesting chronic hepatobiliary injury that represents a major clinical challenge. Whereas biliary senescence and inflammatory damage are crucial to the pathogenesis of biliary liver injury, there are significant gaps in understanding the precise mechanisms of ductular reaction and liver fibrosis. Recent evidence demonstrates stimulator of interferon genes (STING) as a mediator that promotes macrophage-stimulated liver inflammation and fibrosis. In various cell types, STING is activated by cyclic GMP-AMP (cGAMP), whose synthesis is catalyzed by cGAMP synthase (cGAS) in response to the aberrant cytosolic presence of double-stranded DNA (dsDNA), including mitochondrial DNA (mtDNA). During the preliminary studies, we obtained exciting data suggesting the following novel findings: 1) STING expression is increased in cholangiocytes, liver macrophages, and hepatic stellate cells (HSCs) in livers of PSC patients; 2) cholangiocyte- and/or myeloid cell-specific STING disruption alleviates ductular reaction and liver fibrosis during cholestasis; 3) while mtDNA is increased in cholangiocytes from cholestatic mice, extracellular vesicles (EVs) isolated from human PSC cholangiocytes promote macrophage activation in a manner involving STING; and 4) STING-driven macrophage factors increase cholangiocyte expression of genes related to senescence-associated secretory phonotype (SASP) and fibrosis. These findings point to a critical role for STING in regulating cholangiocyte damage and dysfunctional cell-cell crosstalk during biliary liver injury. Based on these findings, we hypothesize that during cholestatic liver injury, STING expression/activation is stimulated in cholangiocytes, liver macrophages, and HSCs through autocrine and paracrine manners via EVs containing mtDNA cargo, which in turn results in dysfunctional cell- cell crosstalk to enhance cholangiocyte SASP, macrophage/HSC activation, and consequent ductular reaction and liver fibrosis. To test the central hypothesis, two Specific Aims will be persued. For Aim 1, experiments involving novel mouse models have been proposed to determine the extent to which cholangiocyte-specific STING disruption alleviates cholestatic-induced ductular reaction and liver fibrosis. Also, cell experiments will be performed to determine the extent to which STING-driven cholangiocyte factors promote macrophage proinflammatory activation and HSC fibrogenic activation. For Aim 2, experiments have been designed to determine the extent to which myeloid cell-specific STING disruption alleviates cholestasis-induced ductular reaction, cholangiocyte SASP, and liver fibrosis in mice. Also, cell experiments will be performed to evaluate the extent to which STING-driven macrophage factors promote cholangiocyte SASP and HSC fibrogenic activation. Successful completion of this project will fill knowledge gaps in biliary liver injury and provide the experimental basis for innovative therapeutic strategies based on STING inhibition.

胆源性肝病，例如原发性硬化性胆管炎（PSC），其特点是肝损伤和胆管细胞的增殖是胆道损伤和上皮下纤维化之间的关键联系，表现为慢性肝胆损伤是一项重大的临床挑战。而胆道衰老和炎症损伤对于胆汁性肝损伤的发病机制至关重要，但目前在胆汁性肝损伤的研究中存在显着的空白了解导管反应和肝纤维化的确切机制。最近的证据表明干扰素基因刺激剂 (STING) 作为促进巨噬细胞刺激的肝脏炎症的介质和纤维化。在各种细胞类型中，STING 由环 GMP-AMP (cGAMP) 激活，其合成是由 cGAMP 合酶 (cGAS) 催化，响应胞质中异常存在的双链 DNA (dsDNA)，包括线粒体DNA (mtDNA)。在初步研究期间，我们获得了令人兴奋的数据提示以下新发现：1）胆管细胞、肝巨噬细胞中 STING 表达增加， PSC 患者肝脏中的肝星状细胞 (HSC)； 2) 胆管细胞和/或骨髓细胞特异性 STING 破坏可减轻胆汁淤积期间的导管反应和肝纤维化； 3）当mtDNA增加时来自胆汁淤积小鼠的胆管细胞，从人 PSC 胆管细胞分离的细胞外囊泡 (EV) 以涉及 STING 的方式促进巨噬细胞活化； 4) STING驱动的巨噬细胞因子增加胆管细胞与衰老相关的分泌表型（SASP）相关基因的表达纤维化。这些发现表明 STING 在调节胆管细胞损伤和功能失调方面发挥着关键作用。胆汁性肝损伤期间的细胞间串扰。基于这些发现，我们假设胆汁淤积性肝损伤后，胆管细胞、肝巨噬细胞和 HSC 中的 STING 表达/激活通过以下方式受到刺激：通过含有 mtDNA 货物的 EV 进行自分泌和旁分泌方式，这反过来又导致细胞功能失调细胞串扰增强胆管细胞 SASP、巨噬细胞/HSC 激活以及随后的导管反应和肝纤维化。为了检验中心假设，将追求两个具体目标。对于目标 1，实验已提出涉及新型小鼠模型来确定胆管细胞特异性的程度 STING 破坏可减轻胆汁淤积引起的导管反应和肝纤维化。此外，细胞实验将确定 STING 驱动的胆管细胞因子促进巨噬细胞的程度促炎性激活和 HSC 纤维化激活。对于目标 2，实验旨在确定骨髓细胞特异性 STING 破坏减轻胆汁淤积诱导的导管的程度反应、胆管细胞 SASP 和小鼠肝纤维化。此外，还将进行细胞实验来评估 STING 驱动的巨噬细胞因子促进胆管细胞 SASP 和 HSC 纤维化激活的程度。该项目的成功完成将填补胆汁性肝损伤的知识空白，并为胆汁性肝损伤提供实验依据。基于 STING 抑制的创新治疗策略的基础。