Na+/H+ exchange in the nematode intestine

线虫肠道中的Na/H交换

• 批准号: 6556372
• 负责人: Keith Nehrke
• 金额: $ 15.75万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6556372
• 关键词: Caenorhabditis elegans; acidity /alkalinity; bioenergetics; gastrointestinal nutrient absorption; glucose transporter; green fluorescent proteins; helminth genetics; mutant; nutrient intake activity; nutrition related tag; oxygen consumption; protein isoforms; protein localization; protein structure function; protein transport; sodium hydrogen exchanger; superoxides; transposon /insertion element

DESCRIPTION (provided by applicant): Deficiencies in Na+/H+ exchange compromise fluid and electrolyte transport in the mammalian intestine. In addition, nutrient absorption via H+-coupled peptide transporters and Na+-glucose co-transporters is pH dependent, and may depend upon intracellular pH regulation through Na+/H + exchange in order to remain active. Although a great deal is known about the structure and function of several Na+/H+ exchanger proteins, to date little is known about the remaining family members. In this proposal, we intend to develop a physiologically simple model system where the role of individual Na+/H+ exchangers in mediating intestinal function can be assessed on a genome-wide level in an intact animal. Towards this end, we have cloned the cDNAs for nine Na+/H+ exchangers from the nematode C. elegans. Aim 1 of this proposal involves determining the cellular, subcellular and temporal expression patterns of these exchangers. Aim 2 is designed to directly test the physiological role of each exchanger in vivo using double-stranded RNA-mediated gene interference in combination with a novel system to measure intracellular pH in an intact nematode, using GFP as a targetable, non-invasive intracellular pH indicator. Preliminary results suggest that nhx-2, an intestinal Na+/H+ exchanger, is involved in regulating the post-embryonic growth of early larval stage nematodes. Thus, Aim 3 is designed to directly assess the role of this exchanger in mediating nutrient absorption. Using a transposon insertion mutant that lacks nhx-2 gene function, we will examine the uptake of nutrients from a bacterial food source and also assess markers of metabolic potential such as oxygen consumption, superoxide production, and ATP/ADP concentrations. This multidisciplinary approach will help to define the biological role of individual Na+/H+ exchangers in the nematode intestine.

描述（由申请人提供）：Na+/H+交换不足会影响哺乳动物肠道中液体和电解质的运输。此外，通过H+偶联肽转运体和Na+-葡萄糖共转运体的营养吸收是pH依赖性的，并且可能依赖于通过Na+/H +交换来调节细胞内pH以保持活性。虽然对几种Na+/H+交换蛋白的结构和功能了解很多，但迄今为止对其余家族成员知之甚少。在这项提议中，我们打算开发一个生理上简单的模型系统，其中单个Na+/H+交换器在调节肠道功能中的作用可以在完整动物的全基因组水平上进行评估。为此，我们克隆了线虫9个Na+/H+交换体的cdna。本提案的目的1涉及确定这些交换器的细胞、亚细胞和时间表达模式。Aim 2旨在利用双链rna介导的基因干扰，结合一种新的系统，直接测试每种交换器在体内的生理作用，以GFP作为可靶向的、非侵入性的细胞内pH指标，测量完整线虫的细胞内pH。初步结果表明，肠道Na+/H+交换剂nhx-2参与线虫早期幼虫期胚胎后生长的调控。因此，Aim 3旨在直接评估该交换剂在介导营养吸收中的作用。使用缺乏nhx-2基因功能的转座子插入突变体，我们将检查从细菌食物来源摄取营养物质，并评估代谢潜力的标记，如氧气消耗、超氧化物产生和ATP/ADP浓度。这种多学科的方法将有助于确定单个Na+/H+交换器在线虫肠道中的生物学作用。