Molecular mechanism of Sickle Cell Hepatic Crisis

镰状细胞性肝危象的分子机制

• 批准号: 10614998
• 负责人: Tirthadipa Pradhan-Sundd
• 金额: $ 7.21万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-15 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10614998
• 关键词: Affect; Age; Agonist; American; Apical; Area; Award; Bile Acids; Bile fluid; Biochemical; Biochemistry; Cholestasis; Chronic; Complement; Experimental Models; Future; Genes; Genetic; Genetic Diseases; Goals; Hematology; Hemoglobin; Hemolysis; Hemolysis Induction; Hepatic; Hepatobiliary; Hepatocyte; Hepatomegaly; Hospitalization; Human; Hyperbilirubinemia; Immunohistochemistry; Impairment; In Vitro; Incidence; Inflammation; Inflammatory; Injury; Institution; Intrahepatic Cholestasis; Ischemia; Liver; Liver Failure; Liver Fibrosis; Liver diseases; Longevity; Mendelian disorder; Mentors; Mentorship; Modeling; Molecular; Mus; NF-kappa B; Nuclear Receptors; Oncology; Outcome; Oxidative Stress; Pathway interactions; Patients; Persons; Preventive therapy; Proteins; Reperfusion Injury; Reporting; Research; Research Personnel; Research Training; Role; Sampling; Scientist; Secondary to; Serum; Sickle Cell; Sickle Cell Anemia; Signal Pathway; Signal Transduction; Sterility; Testing; Therapeutic; Time; Tissues; Toxic effect; Training; Transgenic Organisms; United States National Institutes of Health; Universities; apical membrane; autosome; bile acid transporter; career; chronic liver injury; faculty research; human disease; humanized mouse; improved; in vivo; in vivo imaging; liver biopsy; liver injury; medical schools; meetings; mouse model; multi-photon; novel; prognostic; recessive genetic trait; sex; sickling; therapeutic target; tissue injury; transcriptome sequencing

Project Summary/Abstract The goal of this proposal is to extend my training as an independent scientist in the field of hepatic manifestations of Sickle cell disease (SCD). To this end, I have selected the division of Hematology-Oncology at University of Pittsburgh to continue my transition to become an independent investigator at an academic institution. This proposal outlines an extensive Research Strategy that is complemented by several areas of training, which includes several courses directly related to my studies in Specific Aims, meeting with my junior faculty research committee, and attendance and participation of multiple seminars throughout the University Of Pittsburgh Medical School. My Research Strategy will determine the molecular mechanisms of SCD induced hepatic crisis. SCD is an autosomal-recessive monogenic disorder that affects approximately 100,000 Americans and millions of people worldwide. Sinusoidal vaso-occlusion and hemolysis are considered as chief contributors of sickle hepatic crisis. Hepatic crisis affects 10-40% of hospitalized SCD patients which is characterized by liver injury and sickle cell intrahepatic cholestasis (SCIC) that can progress to fatal liver failure. The current treatment for hepatic crisis is primarily supportive, and the molecular mechanism is unknown, suggesting that preventive therapies based on the improved understanding of the molecular pathways that enable SCIC are needed. In this study, we have used a transgenic, humanized mouse model of SCD that exclusively expresses sickle human hemoglobin. Preliminary findings reveal that SCD mice developed chronic liver injury with age, which was manifested by sustained inflammation, hyperbilirubinemia and cholestasis. Using our recently developed real-time in vivo imaging of the intact liver of live mice, we discovered the presence of sinusoidal ischemia and impaired bile transport across the apical membrane of hepatocytes in SCD mice. The impaired bile transport was associated with loss of apical bile transporters (BSEP, ABCG5 and ABCG8) from hepatocytes. RNA-seq analysis identified dysregulation of genes encoding proteins responsible for inflammation and bile secretion in the liver of SCD mice. Furthermore, we observed NF-κB activation in the liver of SCD mice inhibited FXR signaling and its downstream targets, leading to impaired bile secretion. These findings form the basis for my overarching hypothesis that ischemia and hemolysis induced inflammation, tissue injury and oxidative stress promotes NF-kB activation in sickle hepatocytes which inhibits FXR signaling leading to impaired bile secretion in SCD, and activating FXR or rescuing bile secretion can ameliorate SCIC. This hypothesis will be tested in the following aims: 1) To determine whether ischemia-reperfusion injury and hemolysis promotes hepatocyte specific activation of NF-kB in SCD and 2) To determine whether hepatocyte-specific activation of NF-kB promotes loss of FXR-signaling leading to impaired bile secretion and cholestasis in SCD. The successful completion of this NIH-K01 training award will set the stage for an RO1 proposal aimed at elucidating how the manipulation of inflammatory pathways, FXR signalling and bile secretion can rescue SCIC and progressive liver injury in SCD.

项目摘要/摘要 该提案的目的是扩展我作为肝表现形式领域的独立科学家的培训 镰状细胞疾病（SCD）。为此，我选择了大学的血液肿瘤学系 匹兹堡继续过渡，成为学术机构的独立调查员。这 提案概述了一项广泛的研究策略，该策略由多个培训领域完成，这是 包括与我的特定目标研究直接相关的几门课程，与我的初级教师研究会面 委员会，匹兹堡大学多个半小伙子的出席和参与 医学院。我的研究策略将确定SCD引起的肝危机的分子机制。 SCD是一种常染色体不必要的单基因障碍，影响约100,000美国人和数百万 全世界的人。正弦的血管牙合和溶血被认为是镰刀的主要贡献者 肝危机。肝危机影响10-40％的住院SCD患者，其特征是肝损伤 和镰状细胞腹膜内胆汁淤积（SCIC），可以发展为致命的肝衰竭。当前的治疗方法 肝炎危机主要得到支持，分子机制尚不清楚，表明预防性 基于对启用SCIC的分子途径的理解的改进的疗法。 在这项研究中，我们使用了独家表达镰刀的转基因，人源化的小鼠模型 人血红蛋白。初步发现表明，SCD小鼠随着年龄的增长而出现慢性肝损伤， 由持续注射，高胆红素血症和胆汁淤积表现出来。使用我们最近开发的 实时在活体小鼠完整肝脏的体内成像，我们发现正弦缺血的存在和 SCD小鼠中肝细胞的顶膜的胆汁运输受损。胆汁运输受损 与肝细胞中根顶胆汁转运蛋白（BSEP，ABCG5和ABCG8）的损失有关。 RNA-seq 分析确定了编码负责注射和胆汁分泌蛋白质的基因失调 SCD小鼠的肝脏。此外，我们观察到SCD小鼠肝脏中的NF-κB激活抑制了FXR 信号及其下游目标，导致胆汁分泌受损。这些发现构成了我的基础 总体假设是缺血和溶血诱导的注射，组织损伤和氧化应激 促进镰状肝细胞中的NF-KB激活，该肝细胞抑制FXR信号传导导致胆汁分泌受损 在SCD中，激活FXR或营救胆汁分泌可以改善SCIC。该假设将在 以下目的：1）确定缺血 - 再灌注损伤和溶血是否促进肝细胞特异性 NF-KB在SCD中的激活和2）确定NF-KB的肝细胞特异性激活是否会促进损失 FXR信号导致SCD中的胆汁分泌和胆汁淤积受损。成功完成 NIH-K01培训奖将为RO1提案奠定基础，旨在阐明如何操纵 炎症途径，FXR信号传导和胆汁分泌可以挽救SCD中的SCIC和进行性肝损伤。