TRANSCRIPTIONAL REGULATION OF BILE SALT EXPORT PUMP BY ENDOBIOTICS AND XENOBIOTI

Endobiotics 和 Xenobioti 对胆盐输出泵的转录调控

• 批准号: 7609971
• 负责人: Ruitang Deng
• 金额: $ 1.28万
• 依托单位: UNIVERSITY OF RHODE ISLAND
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7609971
• 关键词: Bile Acids; Bile fluid; Binding; Binding Sites; Biochemical Genetics; Cholestasis; Cholesterol; Computer Retrieval of Information on Scientific Projects Database; Electrophoretic Mobility Shift Assay; Elements; FOS gene; Funding; Grant; Hand; Impairment; In Vitro; Indium; Injury; Institution; JUN gene; Lead; Liver; Mediating; Molecular; Nuclear Receptors; Pathway interactions; Physiological; Pilot Projects; Pump; RNA Interference; Recruitment Activity; Regulation; Research; Research Personnel; Resources; Site; Source; Therapeutic; Therapeutic Effect; Transcriptional Regulation; United States National Institutes of Health; Xenobiotics; bile salts; chromatin immunoprecipitation; hypercholesterolemia; in vivo; pregna-4,17-diene-3,16-dione; promoter; receptor

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Conversion of cholesterol to bile acids and subsequent secretion into bile represents a major pathway in the elimination of excessive cholesterol. Genetic and biochemical studies have established that the bile salt export pump (BSEP) is responsible for the secretion. Impairment of BSEP function or expression by endobiotics and xenobiotics lead to cholestatic liver injury. On the other hand, enhancement of BSEP expression by endobiotics and xenobiotics has therapeutic effect on cholestasis and hypercholesterolemia. Elucidation of the molecular mechanism for the regulation of BSEP expression will have physiological, toxicological and therapeutic significance. The long-term objective of the proposed project is to elucidate the molecular mechanism by which the expression of BSEP is coordinately regulated by endobiotics and xenobiotics through distinct but functionally related pathways. The specific aims of this pilot project are: specific aim #1 to determine whether hypolipidemic guggulsterone-mediated induction of BSEP expression is achieved through the c-Jun/c-fos activation pathway and specific aim #2 to determine whether nuclear receptor liver homology receptor 1 (LRH-1) transcriptionally regulates BSEP expression. Two experimental approaches are proposed for specific aim #1: (a) super electrophoretic mobility shift assay will be performed to determine whether c-Jun/c-fos binds to the guggulsterone responsive element (GuRE) in the BSEP promoter in vitro; (b) chromatin immunoprecipitation will be performed to determine whether c-Jun/c-fos is recruited to the GuRE in vivo. Two experimental approaches are proposed for specific aim #2: (a) LRH-1 expression will be specifically silenced by RNAi and the effect of LRH-1 knockdown on BSEP expression will be determined; (b) mutational analysis of the potential LRH-1 binding sites in the BSEP promoter will be performed to identify the functional LRH-1 site(s).

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 胆固醇转化为胆汁酸并随后分泌到胆汁中代表了消除过量胆固醇的主要途径。遗传和生化研究已经确定，胆盐输出泵（BSEP）负责分泌。内源性和外源性物质对BSEP功能或表达的损害导致胆汁淤积性肝损伤。另一方面，通过内源性和外源性物质增强BSEP表达对胆汁淤积和高胆固醇血症具有治疗作用。阐明BSEP表达调控的分子机制将具有生理、毒理和治疗意义。该项目的长期目标是阐明BSEP的表达通过不同但功能相关的途径由内源性和外源性物质协调调节的分子机制。该试点项目的具体目标是：具体目标#1，以确定是否通过c-Jun/c-fos激活途径实现降血脂guggulsterone介导的BSEP表达诱导，具体目标#2，以确定核受体肝脏同源受体1（LRH-1）是否转录调节BSEP表达。针对特定目标#1提出了两种实验方法：（a）进行超电泳迁移率变动测定，以确定c-Jun/c-fos是否在体外与BSEP启动子中的Gugulsterone反应元件（GuRE）结合;（B）进行染色质免疫沉淀，以确定c-Jun/c-fos是否在体内被募集至GuRE。针对特定目标#2提出了两种实验方法：（a）通过RNAi特异性沉默LRH-1表达，并确定LRH-1敲低对BSEP表达的影响;（B）对BSEP启动子中潜在的LRH-1结合位点进行突变分析，以鉴定功能性LRH-1位点。