Role of STING in Cholestatic Liver Injury

STING 在胆汁淤积性肝损伤中的作用

• 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
• 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

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.

胆汁性肝病，如原发性硬化性胆管炎(PSC)，其特点是损害和 胆管细胞的增殖是胆管损伤和上皮下纤维化的关键环节，表现为 慢性肝胆损伤是一个重大的临床挑战。而胆汁衰老和 炎性损伤在胆汁性肝损伤的发病机制中起着至关重要的作用，在 了解导管反应和肝纤维化的确切机制。最近的证据表明 干扰素基因刺激物(STING)作为促进巨噬细胞刺激的肝脏炎症的介质 和纤维化症。在不同类型的细胞中，STING由环状GMP-AMP(CGAMP)激活，其合成是 由cGAMP合成酶(CGAS)催化，以响应胞浆中双链DNA的异常存在 (DsDNA)，包括线粒体DNA(MtDNA)。在初步研究中，我们获得了令人振奋的数据 提示以下新发现：1)STING在胆管细胞、肝巨噬细胞、 和PSC患者肝脏中的肝星状细胞(HSCs)；2)胆管细胞和/或髓系细胞特异性刺痛 阻断可减轻胆汁淤积期的胆管反应和肝纤维化；3)而线粒体DNA在 胆汁淤积症小鼠的胆管细胞、人PSC胆管细胞的细胞外小泡(EV) 以刺痛的方式促进巨噬细胞活化；以及4)刺痛驱动的巨噬细胞因子 增加胆管细胞衰老相关分泌音型(SASP)相关基因表达 纤维化症。这些发现指出了刺痛在调节胆管细胞损伤和功能障碍中的关键作用。 胆汁性肝损伤时的细胞-细胞串扰。基于这些发现，我们假设在胆汁淤积期肝脏 在胆管细胞、肝巨噬细胞和肝星状细胞中，损伤、刺激性蛋白表达/激活通过 通过含有mtDNA货物的电动汽车以自分泌和旁分泌的方式，进而导致细胞功能障碍- 细胞串扰增强胆管细胞SASP、巨噬细胞/HSC活化及随后的导管反应 和肝纤维化。为了检验这一中心假设，我们将提出两个具体目标。对于目标1，实验 已经提出了涉及新的小鼠模型来确定胆管细胞特异性的程度 止痛可减轻由胆汁淤积引起的胆管反应和肝纤维化。此外，细胞实验将是 以确定刺痛驱动的胆管细胞因子促进巨噬细胞的程度 促炎症激活和HSC纤维化激活。对于目标2，实验被设计为 确定髓系细胞特异性刺伤可在多大程度上减轻胆汁淤积症引起的胆管狭窄 小鼠的反应、胆管细胞SASP和肝纤维化。此外，还将进行细胞实验来评估 刺痛驱动的巨噬细胞因子促进胆管细胞SASP和HSC纤维化活化的程度。 该项目的成功完成将填补胆汁性肝损伤方面的知识空白，并提供实验 基于刺痛抑制的创新治疗策略的基础。