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: 6110574
• 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: 1999
• 资助国家: 美国
• 起止时间: 1999-02-01 至 2000-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6110574
• 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.

这个项目描述了设计用来测试假设的实验 硫氮化物敏感的钠-氯共转运蛋白基因突变 是戈登综合征(GS)的分子基础。戈登综合征是一种 常染色体显性高血压伴高钾血症， 肾小管性酸中毒，肾功能正常。香贝兰假设 这种综合征是由远端肾单位的“氯化物分流”引起的。 根据这一假说，远端肾单位将从 重吸收钠以换取K和H为一的一段 Na主要与氯离子发生重吸收。主要的钠和氯的再吸收 哺乳动物远端小管的通路是一种对噻嗪敏感的钠-氯 辅助传送器。有趣的是，大多数GS星座的迹象对 用小剂量的噻嗪类利尿剂治疗。因此，硫氮化物- 敏感的钠氯共转运蛋白基因是GS的一个很好的候选基因。一个 硫氮化物敏感的钠-氯转运体突变会导致GS 结构性地激活运输蛋白。这种转运蛋白是 最近从冬季比目鱼和哺乳动物的膀胱中克隆出来的。 该蛋白的信息在远端曲管中表达 人类的细胞和连接小管细胞。对噻嗪的上调调控- 连接小管中敏感的Na-Cl共转运可以解释所有 戈登综合征的临床特点。我们已经筛选出一颗宇宙星 含有哺乳动物噻嗪敏感转运蛋白克隆的文库，已鉴定 四个克隆，并在该序列中鉴定出一个多态的GT重复序列 16号染色体上的区域。 这个项目的目的是，L)澄清肾单位的分布 硫氮化物敏感的钠-氯共转运体，布美他尼敏感的钠-钾转运体- 哺乳动物的2Cl共转运蛋白与阿米洛利敏感的钠通道 远端肾单位，2)确定噻嗪敏感的钠离子的特异性调节因子 CL体外共转运，3)检验戈登综合征是 与噻嗪敏感的钠氯共转运蛋白基因连锁，4)鉴定 戈登综合征的特定突变，5)表达正常 和突变的离子转运蛋白在非洲爪哇卵母细胞和哺乳动物细胞系中的表达 筛选转运蛋白活动的功能差异和 监管控制。这些研究的结果将确定基因 一种重要的孟德尔形式的基础和分子生理学 高血压，并导致筛查和治疗的工具。这个 研究结果也应该为特发性脑脊髓炎的发病机制提供线索 高血压，尤其是容量依赖型患者。