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.

胆道肝疾病，例如原发性硬化性胆管炎（PSC），其特征是损害和 胆管细胞的扩散是胆道损伤与上皮纤维化之间的关键联系，表现 代表重大临床挑战的慢性肝损伤。而胆汁衰老和 炎症损伤对于胆道肝损伤的发病机理至关重要，在 了解导管反应和肝纤维化的精确机制。最近的证据表明 干扰素基因（STING）的刺激剂作为促进巨噬细胞刺激的肝脏炎症的介体 和纤维化。在各种细胞类型中，刺激被环状GMP-AMP（CGAMP）激活，其合成为 通过CGAMP合酶（CGA）催化，响应异常胞质的DNA存在 （dsDNA），包括线粒体DNA（mtDNA）。在初步研究中，我们获得了令人兴奋的数据 提出以下新发现：1）胆管细胞，肝巨噬细胞中的刺激表达增加， PSC患者肝脏中的肝星细胞（HSC）； 2）胆管细胞和/或髓样细胞特异性刺激 干扰减轻胆汁淤积过程中的凝性反应和肝纤维化； 3）虽然mtDNA增加 从人PSC胆管细胞分离的胆汁淤积小鼠的胆管细胞，细胞外囊泡（EV） 以涉及刺激的方式促进巨噬细胞激活； 4）刺激驱动的巨噬细胞因子 增加与衰老相关分泌型（SASP）和 纤维化。这些发现表明，在调节胆管细胞损伤和功能失调中刺伤的关键作用 胆道肝损伤期间的细胞细胞串扰。基于这些发现，我们假设在胆固性肝脏中 通过胆管细胞，肝巨噬细胞和HSC刺激损伤，刺激表达/激活 通过含有mtDNA货物的电动汽车的自分泌和旁分泌礼节，这又导致功能失调的细胞 细胞串扰，以增强胆管细胞SASP，巨噬细胞/HSC激活和随之而来的导管反应 和肝纤维化。为了检验中心假设，将实现两个具体的目标。对于目标1，实验 已经提出了涉及新颖的小鼠模型以确定胆管细胞特异性的程度 刺激性减轻胆固醇引起的导管反应和肝纤维化。另外，细胞实验将是 进行的以确定刺激驱动的胆管细胞因子促进巨噬细胞的程度 促炎激活和HSC纤维化激活。对于AIM 2，实验已设计为 确定髓样细胞特异性的刺痛减轻胆汁淤积引起的导管的程度 小鼠的反应，胆管细胞SASP和肝纤维化。此外，将进行细胞实验以评估 刺激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道肝损伤的知识空白，并提供实验 基于抑制的创新治疗策略的基础。