GORDON'S SYNDROME AND THE GENETICS OF SODIUM CHLORIDE TRANSPORT

戈登综合征和氯化钠转运的遗传学

• 批准号: 6302411
• 负责人: DAVID H ELLISON
• 金额: $ 10.91万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-16 至 2001-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6302411
• 关键词: Xenopus oocyte; aldosterone; amiloride; autosomal dominant trait; clinical research; familial hypertension; family genetics; gene mutation; hormone regulation /control mechanism; human subject; immunocytochemistry; in situ hybridization; ion transport; laboratory mouse; linkage mapping; mineralocorticoids; molecular cloning; molecular genetics; northern blottings; polymerase chain reaction; protein kinase C; renal tubular transport; sodium channel; sodium chloride; thiazide

This project describes experiments designed to test the hypothesis that a mutation in the gene encoding the thiazide-sensitive Na-Cl cotransporter is the molecular basis of Gordon's syndrome (GS). Gordon's syndrome is an autosomal dominant form of hypertension associated with hyperkalemia, renal tubular acidosis, and normal renal function. Shambelan postulated that this syndrome was caused by a "chloride shunt" in the distal nephron. According to this hypothesis, the distal nephron would be transformed from a segment that reabsorbed Na in exchange for K and H to one that reabsorbed Na primarily with Cl. The predominant Na and Cl reabsorptive pathway of the mammalian distal tubule is a thiazide-sensitive Na-Cl cotransporter. Interestingly, most signs of GS are remarkably sensitive to treatment with low doses of thiazide diuretics. Thus, the thiazide- sensitive Na-Cl cotransporter is an excellent candidate gene for GS. A mutation in the thiazide-sensitive Na-Cl transporter causing GS would constitutively activate the transport protein. This transport protein was recently cloned from the bladder of the Winter Flounder and from mammals. The message for this protein is expressed in distal convoluted tubule cells and connecting tubule cells in humans. Up regulation of thiazide- sensitive Na-Cl cotransport in the connecting tubule could explain all of the clinical features of Gordon's syndrome. We have screened a cosmid library with a mammalian thiazide-sensitive transporter clone, identified four clones, and identified a polymorphic GT repeat motif within this region on chromosome 16. The aims of this project are to, l) clarify the nephron distribution of the thiazide-sensitive Na-Cl cotransporter, the bumetanide-sensitive Na-K- 2Cl cotransporter and the amiloride-sensitive Na channel in the mammalian distal nephron, 2) identify specific regulators of thiazide-sensitive Na- Cl cotransport in vitro, 3) test the hypothesis that Gordon's syndrome is linked to the thiazide-sensitive Na-Cl cotransporter gene, 4) identify the specific mutation responsible for Gordon's syndrome, and 5) express normal and mutated ion transporters in Xenopus oocytes and mammalian cell lines to screen for functional differences in transporter activity and regulatory control. The results of these studies will identify the genetic basis and the molecular physiology of an important Mendelian form of hypertension and lead to tools for both screening and treatment. The results should also provide clues to the pathogenesis of essential hypertension especially in volume dependent patients.

该项目描述了旨在检验假设的实验 编码噻嗪类敏感的Na-Cl共转运蛋白的基因突变 是戈登综合征（GS）的分子基础。戈登综合症是 与高钾血症相关的高血压的常染色体显性形式， 肾小管酸中毒和正常的肾功能。 Shambelan假设 该综合征是由远端肾单位中的“氯化物分流器”引起的。 根据这一假设，远端肾单位将从 一个重新吸收Na以换取K和H的部分 主要用Cl重新吸收Na。主要的NA和CL重吸收性 哺乳动物远端小管的途径是对噻嗪类敏感的Na-Cl 共转运者。有趣的是，大多数GS的迹象对 低剂量的噻嗪类利尿剂治疗。因此，噻嗪 敏感的Na-Cl共转运蛋白是GS的出色候选基因。一个 噻嗪类敏感的Na-Cl转运蛋白引起GS的突变会 组成性激活转运蛋白。该转运蛋白是 最近从冬季比目鱼和哺乳动物的膀胱克隆。 该蛋白质的消息以远端曲折小管表示 细胞和连接人类中的小管细胞。提高噻嗪类的调节 连接小管中敏感的Na-Cl共同运动可以解释所有 戈登综合征的临床特征。我们已经筛选了一个宇宙 带有哺乳动物硫嗪敏感转运蛋白克隆的库，已鉴定 四个克隆，并在此内鉴定出一个多态性GT重复基序 染色体16的区域。 该项目的目的是，l）阐明 噻嗪类敏感的Na-Cl共转运蛋白，对木甲化的Na-k- 2Cl共转运蛋白和哺乳动物中对艾米洛德敏感的Na通道 远端肾单位，2）确定对噻嗪敏感的Na-的特定调节剂 体外Cl Cotransport，3）检验戈登综合征的假设 与噻嗪类敏感的Na-Cl共转运蛋白基因相关，4）确定 负责戈登综合征的特定突变，5）表达正常 异爪蟾卵母细胞和哺乳动物细胞系中的突变离子转运蛋白 筛选转运蛋白活性的功能差异和 监管控制。这些研究的结果将确定遗传 重要的孟德尔形式的基础和分子生理 高血压并导致用于筛查和治疗的工具。这 结果还应为必需的发病机理提供线索 高血压，尤其是在体积依赖患者中。