DEVELOPMENTAL REGULATION OF ENAC EXPRESSION

ENAC 表达的发育调控

• 批准号: 6270839
• 负责人: PAUL B MCCRAY
• 金额: $ 16.01万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-17 至 1999-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6270839
• 关键词: RNase protection assay; angiotensin /renin /aldosterone hypertension; animal genetic material tag; colon; corticotropin releasing factor; developmental genetics; epithelium; gene induction /repression; genetically modified animals; glucocorticoids; kidney; laboratory mouse; laboratory rat; lung; sodium channel; urinary tract

The main objective of this proposal is to determine the ontogeny, localization and regulation of expression by glucocorticoids for the ENaC subunits in the developing kidney, uroepithelium, lung and colon. The recent evidence that hypertension associated with Liddle~s syndrome is due to mutations in the beta and gamma ENaC subunits and the finding that young prehypertensive Dahl salt-sensitive rates have increase Na+ absorption via apical membrane amiloride-sensitive sodium channels int he IMCD epithelia provide the rationale for the further study of EnaC as a potentially important molecule in the pathogenesis of hypertension. there are 2 specific aims. The first specific aim is to determine the ontogeny of expression and cell specific localization of the ENaC subunits in normal and Dahl S & R rats. ENaC plays important functional roles in the developing kidney, lung and colon and may be very important in the transition from intrauterine to extrauterine life. the expression of functional Na+ channels is dependent on the synthesis of at least 3 proteins, thus the regulation of each may be important for the appropriate cell- and organ-specific function. Since ontogeny is organ specific, learning the pattern of mRNA expression is a critical first step in understanding how each subunit is regulated. Knowing the pattern of expression will permit the generation of hypotheses regarding factors influencing regulation. We hypothesize that differences in the ontogeny or level of expression of ENaC subunits in the kidney plan an important role in the development of hypertension in Dahl rats. To test this hypothesis we will compare the ontogeny of expression and localization of ENaC subunit mRNA and protein in Na+ transporting tissues of normal and Dahl S and R rates using ribonuclease protection assays, in situ hybridization, and immunochemistry. The second specific aim is to determine the role of glucocorticoids (GC) in the regulation of ENaC expression in development. In adult animals corticosteroids influence ENaC mRNA and protein expression in kidney, lung and colon. We hypothesize that ENaC expression during development is regulated in part by GC hormones. To test this hypothesis we will use an in vivo model to assess the effects of GC's on expression of ENaC subunit mRNAs and proteins. The corticicotropin releasing hormone (CRH) knockout (KO) mouse, which has a severely impaired ability to secrete GC will serve as a model to study the role of GCs in the regulation of ENaC expression. This will allow us to selectively determine the effect of GCs on ENaC subunit expression in the developing kidney and lung. The ontogeny and localization of ENaC subunit mRNA expression will be determined in wild type mice. CRH KO mice and CRH Ko in which the mothers receive GC replacement. These studies should conclusively determine the importance of glucocorticoids in the regulation of ENaC expression during development.

该提案的主要目的是确定个体发育， 糖皮质激素对表达的定位和调节 发育中的肾脏，肠上皮，肺和发育中的ENAC亚基 冒号。 最近的证据表明高血压与 LIDDLE〜S综合征是由于Beta和Gamma中的突变引起的 ENAC亚基和年轻的型前dahl的发现 盐敏感的速率通过顶端增加了Na+吸收 膜上对艾米洛里德敏感的钠通道 上皮为进一步研究ENAC作为一个的基本原理提供了理由 高血压发病机理中的潜在重要分子。 有2个具体目标。 第一个具体目的是确定 ENAC的表达和细胞特异性定位的个体发育 正常和DAHL S＆R大鼠的亚基。 ENAC发挥重要作用 发育中的肾脏，肺和结肠的功能角色以及可能 在从宫内到外丁的过渡非常重要 生活。 功能性Na+通道的表达取决于 至少3种蛋白质的合成，因此每个蛋白的调节可能是 对于适当的细胞和器官特异性功能很重要。 由于个体发育是特定器官的，因此学习mRNA的模式 表达是理解每个亚基的关键第一步 受监管。 知道表达方式将允许 关于影响调节的因素的产生的假设。 我们假设个体发育或水平的差异 在肾脏中表达ENAC亚基在计划中的重要作用 达尔大鼠高血压的发展。 测试这个 假设我们将比较表达和 ENAC亚基mRNA和Na+中的蛋白质定位 使用正常和DAHL S和R速率的组织运输 核糖核酸酶保护测定，原位杂交和 免疫化学。 第二个具体目的是确定角色 糖皮质激素（GC）的ENAC表达调节 发展。 在成年动物中，皮质类固醇会影响ENAC 肾脏，肺和结肠中的mRNA和蛋白质表达。 我们 假设开发过程中的ENAC表达受到调节 部分由GC激素。 为了检验该假设，我们将使用 体内模型评估GC对ENAC表达的影响 亚基mRNA和蛋白质。 皮质激素释放 激素（CRH）敲除（KO）小鼠，其严重 分泌GC的能力受损将作为研究 GC在ENAC表达调节中的作用。 这将允许 我们有选择地确定GC对ENAC亚基的影响 在发育中的肾脏和肺中表达。 个体发育和 将确定ENAC亚基mRNA表达的定位 在野生型小鼠中。 CRH KO老鼠和CRH KO，其中 母亲将获得GC的更换。 这些研究应该 最终确定糖皮质激素在 在发育过程中调节ENAC表达。