Molecular targets in cholestasis caused by bile salt export pump deficiency

胆盐输出泵缺陷引起的胆汁淤积的分子靶点

• 批准号: 10456780
• 负责人: Chunyue Yin
• 金额: $ 32.85万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-20 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10456780
• 关键词: ABCB1 gene; ATP-Binding Cassette Transporters; Accounting; Adult; Age; Alternative Therapies; Animal Model; Animals; Attenuated; Autophagocytosis; Bile Acids; Bile fluid; Child; Cholestasis; Cytoplasm; Data; Excretory function; Exhibits; Genes; Genetic; Goals; Health; Hepatocyte; Heterozygote; Human; Impairment; In Vitro; Knockout Mice; Knowledge; Life; Liver; Liver diseases; Membrane; Mission; Modeling; Molecular; Molecular Target; Mutation; Neonatal; Orthologous Gene; Outcome; Patient-Focused Outcomes; Patients; Phenotype; Primary carcinoma of the liver cells; Progressive intrahepatic cholestasis; Public Health; Pump; Research; Severities; Sirolimus; Testing; Trehalose; United States National Institutes of Health; Vesicle; Zebrafish; base; bile salts; design; disability; early onset; end stage liver disease; experimental study; genome sequencing; hepatocyte injury; improved; in vivo; infancy; innovation; liver injury; liver transplantation; mTOR Inhibitor; mutant; new therapeutic target; novel; novel strategies; novel therapeutics; predictive marker; premature; restoration; targeted treatment; whole genome

PROJECT SUMMARY/ABSTRACT In humans, mutations in the ABCB11 gene impair bile salt export pump (BSEP) function and cause progressive familial intrahepatic cholestasis type II (PFIC2), which is a fast-progressing and often-fatal liver disease in infancy. Liver transplantation remains as the only curable treatment for many PFIC2 patients. The main challenge for developing alternative therapy is that there is no known mechanism allowing restoration of bile excretion in the absence of BSEP. Our long-term goal is to discover molecular targets to treat cholestatic liver diseases. The overall objective for this application is to identify mechanisms that can be activated to restore bile excretion in the context of BSEP deficiency. Based on the preliminary data generated using the abcb11b mutant zebrafish, the central hypothesis is that alternative transporters can be prompted to excrete bile acids in BSEP-deficient hepatocytes. The rationale for the proposed research is that, finding the alternative bile salt transporter and delineating the molecular mechanisms triggering its bile excretion function will facilitate the designing of targeted therapies to treat cholestasis caused by BSEP deficiency. Identifying novel strategies to modulate bile secretion will also benefit the patients with other cholestatic liver diseases. The central hypothesis will be tested by the experiments proposed in three complementary specific aims: 1) Determine the alternative transporter that can be prompted to excrete bile acids in BSEP-deficient hepatocytes; 2) Define the cellular and molecular mechanisms that can be activated to restore bile excretion in BSEP-deficient hepatocytes; and 3) Identify genetic modifiers that restore bile excretion in BSEP-deficient hepatocytes. The first aim will test the hypothesis that recovering the localization of another ABC transporter MDR1 to the bile canaliculus allows it to assume bile excretion function in BSEP-deficient hepatocytes. The second aim will investigate whether augmentation of autophagy represents a novel mechanism to restore bile excretion in hepatocytes with BSEP deficiency. The third aim will utilize an unbiased whole-genome sequencing approach to identify genetic modifiers of BSEP-deficiency phenotype severity. The research proposed in this application is highly innovative, because it uses the zebrafish model that offers unique advantages for studying bile excretion, and abcb11b mutant zebrafish is the first animal model in which loss of BSEP results in severe perturbation of bile excretion as seen in patients with PFIC2. The proposed research is significant, because it is expected to reveal strategies to restore bile excretion in BSEP-deficient hepatocytes and uncover new therapeutic targets for treating cholestatic liver diseases.

项目摘要/摘要 在人类中，ABCB11基因中的突变损害了胆汁盐出口泵（BSEP）功能，并导致 进行性家族性肝内胆汁淤积II型（PFIC2），这是一种快速促进的肝脏 婴儿期。对于许多PFIC2患者，肝移植仍然是唯一可以治愈的治疗方法。 开发替代疗法的主要挑战是没有已知的机制 在没有BSEP的情况下，胆汁排泄的恢复。我们的长期目标是发现分子靶标 治疗胆汁淤积性肝病。该应用程序的总体目标是确定可以 在BSEP缺乏症的背景下，被激活以恢复胆汁的排泄。基于初步数据 使用ABCB11b突变体斑马鱼产生的中心假设是替代转运蛋白可以是 提示在缺乏BSEP的肝细胞中排泄胆汁酸。拟议研究的理由是 那就找到了替代的胆汁盐转运蛋白并描述触发其胆汁的分子机制 排泄功能将促进靶向疗法的设计，以治疗由BSEP引起的胆汁淤积 不足。确定调节胆汁分泌的新型策略也将使患者受益于其他 胆汁淤积性肝病。中央假设将通过提出的三个实验测试 补充特定目的：1）确定可以提示排泄胆汁的替代转运蛋白 BSEP缺陷型肝细胞中的酸； 2）定义可以激活的细胞和分子机制 恢复缺乏BSEP的肝细胞中的胆汁排泄； 3）确定恢复胆汁的遗传修饰符 BSEP缺陷肝细胞的排泄。第一个目的将检验恢复的假设 将另一个ABC转运蛋白MDR1定位到胆管造成的允许胆汁排泄物 在BSEP缺陷型肝细胞中的功能。第二个目标将调查是否增加 自噬代表了一种新型机制，可以恢复BSEP缺乏症中肝细胞中胆汁排泄的机制。 第三个目标将利用公正的全基因组测序方法来识别 BSE不足表型严重程度。本应用程序中提出的研究具有很高的创新性， 因为它使用斑马鱼模型，该模型为研究胆汁排泄提供了独特的优势，而ABCB11b 突变斑马鱼是第一个动物模型，其中BSEP的损失导致严重的胆汁扰动 排泄物如PFIC2患者所见。拟议的研究很重要，因为它有望 揭示恢复BSEP缺乏肝细胞中胆汁排泄的策略，并发现新的治疗 治疗胆固性肝病的靶标。