Cholangiocyte-Derived Endothelin Signaling Mediates Biliary Injury and Liver Fibrosis

胆管细胞衍生的内皮素信号传导介导胆道损伤和肝纤维化

• 批准号: 10341130
• 负责人: Lindsey Kennedy
• 金额: --
• 依托单位: RLR VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10341130
• 关键词: Angiogenic Factor; Angiopoietin-2; Architecture; Automobile Driving; Biliary; Biology; Blood; Blood Vessels; Blood capillaries; Cell Proliferation; Cell Separation; Cellular biology; Cholangiocarcinoma; Cholestasis; Chronic; Cirrhosis; Collagen; Complex; Corrosion Casting; Coupled; Data; Deposition; Development; Disease Progression; Down-Regulation; Duct (organ) structure; Endothelin; Endothelin-1; Endothelin-2; Endothelin-3; Epithelial Cells; FDA approved; Feedback; Goals; Growth; HIF1A gene; Hepatic; Hepatic Stellate Cell; Human; Incidence; Inflammation; Injections; Injury; Ink; Knock-out; Lead; Ligation; Liver; Liver Cirrhosis; Liver Fibrosis; Liver diseases; Malignant neoplasm of liver; Mediating; Mentors; Mentorship; MicroRNAs; Modeling; Morbidity - disease rate; Multi-Drug Resistance; Mus; Nutrient; Patients; Pharmaceutical Preparations; Pharmacotherapy; Phenotype; Portal Hypertension; Portal Pressure; Proliferating; Pulmonary Hypertension; Research; Research Proposals; Risk; Role; Safety; Signal Transduction; Techniques; Therapeutic; Tissues; Training; Transforming Growth Factors; VEGFA gene; Vascular Endothelial Cell; Vasoconstrictor Agents; Veterans; Work; ambrisentan; angiogenesis; antagonist; autocrine; base; bile duct; bile stricture; blood vessel development; career; cell growth; cholangiocyte; hypoxia inducible factor 1; in vivo; liver inflammation; liver injury; liver transplantation; mortality; mortality risk; mouse model; novel; novel therapeutics; paracrine; primary sclerosing cholangitis; restoration; senescence; symposium; therapeutically effective; vascular bed

The main goal of this application is to clarify the signaling mechanisms mediating biliary senescence and angiogenesis during primary sclerosing cholangitis (PSC). It is known that (i) endothelin (ET)-1 signaling is enhanced in the bile duct ligation (BDL) model of obstructive cholestasis, (ii) it is primarily upregulated in cholangiocytes and (iii) enhances liver fibrosis via hepatic stellate cell (HSC) activation. Outside of the liver, ET-1 is a potent vasoconstrictor and enhances transforming growth factor-β1 (TGF-β1, pro-angiogenic factor) expression in vascular endothelial cells (VECs). Overall, it is unknown how ET signaling (including ET-2 and ET- 3) mediate biliary senescence and VEC proliferation/angiogenesis during PSC. Additionally, changes in the vascular bed and VEC proliferation during PSC is unknown. We found that ET-1, ET-2, ET-3 and ET-A and ET-B are increased, particularly in cholangiocytes and VECs, in human PSC and the multidrug resistance-2 knockout (Mdr2-/-) mouse model of PSC. Furthermore, we have novel preliminary data showing increased VEC proliferation and angiogenesis in both human PSC and in Mdr2-/- mice. Changes in angiogenesis versus vasopenia during cholestasis is controversial, but considering PSC patients with portal hypertension have an increased morbidity and mortality, there is likely some underlying VEC-mediated changes occurring. Therefore, our novel findings are the first to indicate liver VEC proliferation and angiogenesis during PSC. Additionally, these findings are the first to delve into ET signaling in cholangiocytes and VECs during PSC. We provide data indicating a feedback loop, whereby ET signaling promotes TGF-β1 expression, which can in turn increase miR- 125b/HIF-1α expression, which is known to increase ET expression. These are the first data demonstrating a positive feedback loop between ET/TGF-β1/miR-125b/HIF-1α that can perpetuate biliary senescence and liver fibrosis in autocrine and paracrine manners. Furthermore, we found that inhibition of ET-A or ET-B in Mdr2-/- mice using currently FDA-approved drugs (for the treatment of pulmonary hypertension) reduces biliary senescence and liver fibrosis when compared to controls. Our overall hypothesis is that cholangiocytes and liver VEC communicate with one another via endothelin ET/TGF-β1 signaling that increases biliary senescence and VEC angiogenesis through autocrine and paracrine mechanisms. Our findings may lead to the identification of new, effective therapeutics for the treatment of PSC. This application proposal is the first step to developing independence for the PI, Dr. Lindsey Kennedy. This proposal elegantly marries the background work of her mentors on cholangiocyte biology, microRNA signaling and angiogenesis with new techniques and concepts that further delve into vascular biology during cholestasis. Following successful completion of this application, Dr. Kennedy will have a better understanding of angiogenesis/vasopenia, VEC biology and vascular interactions with the bile ducts, and this can develop into independent studies. The KEY ELEMENTS of this research proposal are the (i) strong mentoring team developed, who will provide top-tier training for the applicant, (ii) introduction of new techniques (ink injection, corrosion casting, VEC isolation, human primary cell isolation) and concepts (vascular biology in cholestasis), (iii) comprehensive mentoring and career plan, including one-on-one training, conference attendance, presentation opportunities and development of grantsmanship, and (iv) opportunity for the applicant to develop her own independent, successful research lab.

本应用的主要目的是阐明介导胆道衰老的信号机制