Coordinated SLC12A3/SLC12A6/SL26A4 electroneutral transport pathways maintain K+ homeostasis and acid-base balance

协调的 SLC12A3/SLC12A6/SL26A4 电中性转运途径维持 K 稳态和酸碱平衡

基本信息

批准号：
10735503
负责人：
Eric J Delpire
金额：
$ 78.36万
依托单位：
VANDERBILT UNIVERSITY MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-06-15 至 2027-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10735503
关键词：
Ablation Acid-Base Equilibrium Alkalosis Animals Anions Apical Bicarbonates Cell membrane Cell model Cellular biology Chlorides Consumption Coupling Data Diet Dietary Potassium Distal Distal convoluted renal tubule structure Ensure Equilibrium Excretory function Food Genes Genetic Transcription Genetically Engineered Mouse Gitelman syndrome Homeostasis In Vitro Intake Intercalated Cell Investigation Kidney Knockout Mice Knowledge Link Mediating Metabolic Modeling Molecular Mus Nephrons Pathway interactions Persons Phenotype Phosphorylation Physiological Physiology Potassium Proteins Public Health Publishing Regulation Role SLC12A3 gene Sodium Sodium Chloride Syndrome Testing Textbooks Therapeutic Intervention Translations Variant Vegetarian diet Wild Type Mouse absorption apical membrane chloride-cotransporter potassium clinical care dietary in vitro Model in vivo inhibitor innovation interdisciplinary approach knockout animal mouse model multidisciplinary novel novel therapeutics potassium bicarbonate preservation prevent programs response symporter targeted treatment thiazide urinary wasting

项目摘要

Alkaline diets and alkalemia have a profound impact on potassium homeostasis, but the underlying mechanisms remain poorly understood. Here we propose an innovative plan to close this significant knowledge gap, building on our recent discovery of a long sought-after electroneutral potassium transport pathway. Our data reveal that dietary alkaline loading stimulates the expression of the electroneutral KCl cotransporter, KCC3a (Slc12a6), in parallel with the Cl-/HCO3- exchanger, pendrin (Slc26a4), on the B- type intercalated cell apical membrane and the activation of the thiazide-sensitive sodium-chloride, NCC (Slc12a3), in the Distal Convoluted Tubule. Here we advance the overarching hypothesis that KCC3a is the long sought-after electroneutral potassium secretory pathway and propose the novel idea that coupling between KCC3a, pendrin, and NCC maintains potassium and acid-base balance in response to the consumption of alkaline and potassium-rich foods but drives potassium wasting in alkalosis. This new model will be rigorously tested by a multidisciplinary team of experts, combining state-of-the-art cellular biology and physiological phenotyping in novel genetically engineered mouse models. Aim 1 will test the hypothesis that KCC3a is activated in response to the consumption of alkaline diets and alkalosis to drive urinary potassium excretion. Intercalated-cell-specific KCC3 knockout mice will be investigated to a) test the contribution of KCC3 to potassium balance and b) to pendrin-mediated HCO3- secretion; c) elucidate the molecular mechanisms that underlie the regulation of KCC3 expression; c) test if KCC-specific inhibitors prevent the loss of K+ in alkalemia. Aim 2 will test the hypothesis that pendrin is co-activated with KCC3a to increase KHCO3 secretion. Pendrin knockout mice will be studied to determine: a) the contribution of pendrin to the regulation of KCC3a; and b) the physiologic consequences of uncoupling the transporters. We will also explore if KCC3a regulates pendrin through changes in pendrin transcription that involve changes in intracellular chloride. Aim 3 will test the hypothesis that alkalosis drives WNK-SPAK mediated phospho-activation of NCC to ensure electroneutral potassium bicarbonate secretion prevails over electrogenic potassium secretion. Newly developed DCT-specific loss and gain of SPAK mice and in vitro cell models will be examined to rigorously test this idea and explore the mechanism. In summary, this program of investigation should illuminate a new mechanism to explain how K+ and acid-base balance are preserved with the consumption of alkaline and potassium-rich foods, typical of the paleolithic and vegetarian diets. The investigation is also expected to change the textbook explanation of urinary potassium wasting in alkalosis, opening a new therapeutic horizon.

碱性饮食和碱性对钾稳态有深远的影响，但基础机制仍然很少理解。在这里，我们提出了一个创新计划，以结束这一重要的知识差距，建立在我们最近发现的长期受欢迎的电荷钾运输的基础上路径。我们的数据表明，饮食碱中的载荷刺激了电自动的KCL的表达 cotransporter，KCC3A（SLC12A6），与cl-/hco3-交换器Pendrin（SLC26A4）并行类型的插入细胞顶膜和噻嗪类敏感钠氯化物NCC的激活（SLC12A3），在远端曲折小管中。在这里，我们推进了KCC3A的总体假设长期追捧的电荷钾分泌途径，并提出了耦合的新颖想法在KCC3A，Pendrin和NCC之间，响应于食用碱性和富含钾的食物，但驱动钾盐中的钾浪费。这个新模型将由多学科的专家团队严格测试，结合最先进的蜂窝新型基因工程小鼠模型中的生物学和生理表型。 AIM 1将测试假设KCC3A是响应碱性饮食和碱性驱动而激活的KCC3A 尿钾排泄。将研究插量细胞特异性的KCC3敲除小鼠进行a）测试 KCC3对钾平衡的贡献和b）Pendrin介导的HCO3-分泌； c）阐明 KCC3表达调节的基础的分子机制； c）测试是否特定于KCC 抑制剂可防止碱性血症中K+的损失。 AIM 2将检验pendrin共同激活的假设 KCC3A增加KHCO3分泌。将研究Pendrin敲除小鼠以确定：a） Pendrin对KCC3A的规定的贡献； b）解耦的生理后果运输商。我们还将探索KCC3A是否通过Pendrin转录的变化来调节Pendrin 涉及细胞内氯化物的变化。 AIM 3将检验以下假设：碱性病驱动WNK-Spak NCC的介导的磷酸激活以确保碳酸氢钾分泌占上风促进电钾分泌。新开发的DCT特异性损失和SPAK小鼠的增益以及将检查体外细胞模型以严格测试这一想法并探索机制。总而言之，这调查计划应阐明一种新的机制，以解释K+和酸碱平衡如何保存在碱性和富含钾的食物的食用中，典型的旧石器时代和素食。预计调查还会改变尿的教科书说明碱性病中的钾浪费，打开了新的治疗视野。