Regulation of K+ balance by distal nephron TRPV4 channel

远端肾单位 TRPV4 通道对 K 平衡的调节

基本信息

批准号：
10439631
负责人：
Oleh Pochynyuk
金额：
$ 34.65万
依托单位：
UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-18 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10439631
关键词：
Acid-Base Equilibrium Address Animal Model Animals Arrhythmia Cardiovascular system Cells Chronic Kidney Failure Clinical Development Diet Dietary Potassium Distal Duct (organ) structure Electrolytes Electrophysiology (science)Epithelial Cells Equilibrium Excretory function Fruit Functional disorder Genetic H(+)-K(+)-Exchanging ATPase Homeostasis Human Hyperaldosteronism Hypokalemia Image Ingestion Intake Kidney Life Maintenance Measurement Mediating Microscopy Molecular Monitor Mus Muscle Nephrons Neurons Osmolar Concentration Pathology Permeability Pharmacology Physiological Physiology Potassium Process Publishing Regimen Regulation Renal function Rodent Role Scheme Signal Transduction Site Testing Tissues Tubular formation Urine Vanilloid Variant Water base cardiovascular health dietary manipulation extracellular genetic manipulation hyperkalemia knockout animal large-conductance calcium-activated potassium channels novel strategies patch clamp receptor recruit response urinary

项目摘要

SUMMARY Tight regulation of K+ balance is fundamental for normal physiology. Disturbed K+ homeostasis is associated with a wide spectrum of cardiovascular- and kidney-related pathologies. The distal nephron (DN), including the connecting tubule (CNT) and the collecting duct (CD), is the major site of controlled potassium transport in the kidney, which is essential to match urinary K+ excretion to varying dietary K+ intake. In this proposal, we posit that the mechanosensitive Ca2+-permeable TRPV4 channel abundantly expressed in the DN is a critical determinant of renal potassium handling capable of stimulating flow-dependent K+ secretion via maxi-K (BK) channel and inhibiting H+-K+ ATPase-dependent K+ reabsorption. We generated abundant supportive evidence that the TRPV4 activity in the DN is regulated by dietary potassium intake with its dysfunction causing significant distortions of systemic K+ balance. TRPV4 -/- mice have a markedly reduced BK channel activity in the DN and develop hyperkalemia when dietary potassium intake is high. On the contrary, TRPV4 deletion augments H+-K+ ATPase activity and protects against hypokalemia when dietary potassium intake is low. Overall, we hypothesize that TRPV4 serves as a physiologically relevant kaliuretic factor during adaptations to dietary potassium regimen by stimulating BK-mediated K+ secretion and inhibiting H+-K+ ATPase-dependent K+ reabsorption. To address this central hypothesis, we developed three specific aims: SA1: Examine molecular and signaling determinants of TRPV4 regulation in the DN by dietary K+ intake. SA2: Establish the importance of TRPV4 function for BK-mediated K+ secretion in the DN and define pathophysiological ramifications of its disruption on systemic K+ balance. SA3: Explore the mechanism and relevance of regulation of K+ reabsorption in the DN by TRPV4. To bring this project to fruition, we recruit strong collaborative expertise and implement a comprehensive experimental arsenal which involves monitoring TRPV4 and BK channels activity with patch clamp electrophysiology, intracellular Ca2+ and H+-K+ ATPase-mediated pH measurements, confocal immunofluorescent microscopy in native DN cells of rodents and humans, balance studies upon manipulation of dietary K+ intake in conventional and genetically manipulated animals. Overall, we expect to directly demonstrate the physiological relevance of mechanosensitive TRPV4 channel in the DN at the systemic level and will define pathophysiological ramifications of TRPV4 dysfunction on systemic K+ homeostasis. Furthermore, this will urge development of novel strategies based on targeting TRPV4 to manage life-threatening states of hyper- and hypokalemia in clinical setting.

概括严格调节 K+ 平衡是正常生理的基础。 K+ 稳态紊乱与之相关具有广泛的心血管和肾脏相关病理。远端肾单位 (DN)，包括连接小管（CNT）和集合管（CD）是细胞内控制钾转运的主要场所。肾脏，这对于使尿 K+ 排泄与不同的膳食 K+ 摄入量相匹配至关重要。在这个提案中，我们假设 DN 中大量表达的机械敏感性 Ca2+ 渗透性 TRPV4 通道是一个关键肾钾处理的决定因素，能够通过 maxi-K (BK) 刺激流量依赖性 K+ 分泌通道并抑制 H+-K+ ATP 酶依赖性 K+ 重吸收。我们产生了丰富的支持证据 DN 中的 TRPV4 活性受膳食钾摄入量的调节，其功能障碍会导致显着的系统性 K+ 平衡的扭曲。 TRPV4 -/- 小鼠 DN 中的 BK 通道活性显着降低，并且当膳食钾摄入量高时，会出现高钾血症。相反，TRPV4 缺失增强了 H+-K+ 当膳食钾摄入量较低时，ATP 酶活性可防止低钾血症。总的来说，我们假设 TRPV4 在适应饮食钾方案期间充当生理相关的利尿因子通过刺激 BK 介导的 K+ 分泌并抑制 H+-K+ ATP 酶依赖性 K+ 重吸收。为了解决这一中心假设，我们制定了三个具体目标： SA1：检查分子和通过膳食 K+ 摄入来调节 DN 中 TRPV4 的信号决定因素。 SA2：建立 TRPV4 功能对于 DN 中 BK 介导的 K+ 分泌的重要性并定义病理生理学它破坏系统性 K+ 平衡的后果。 SA3：探索机制和相关性 TRPV4 调节 DN 中的 K+ 重吸收。为了使这个项目取得成果，我们招募了强大的协作专业知识并实施全面的实验库，其中包括监测 TRPV4 和 BK 通过膜片钳电生理学、细胞内 Ca2+ 和 H+-K+ ATP 酶介导的 pH 通道活动测量、啮齿动物和人类天然 DN 细胞的共聚焦免疫荧光显微镜、平衡对传统动物和基因改造动物的膳食 K+ 摄入量进行控制的研究。总的来说，我们期望直接证明 DN 中机械敏感 TRPV4 通道的生理相关性系统水平，并将定义 TRPV4 功能障碍对系统 K+ 的病理生理学影响体内平衡。此外，这将促使开发基于针对 TRPV4 的新策略来管理临床环境中危及生命的高钾血症和低钾血症。

项目成果

期刊论文数量（7）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Independent regulation of Piezo1 activity by principal and intercalated cells of the collecting duct.

集合管主细胞和闰细胞对 Piezo1 活性的独立调节。

DOI：
发表时间：
2024-01
期刊：
影响因子：
0
作者：
Pyrshev, Kyrylo;Atamanchuk;Kordysh, Mariya;Zaika, Oleg;Tomilin, Viktor N;Pochynyuk, Oleh
通讯作者：
Pochynyuk, Oleh

Adenosine inhibits the basolateral Cl- ClC-K2/b channel in collecting duct intercalated cells.

腺苷抑制集合管闰细胞中的基底外侧 Cl-ClC-K2/b 通道。

DOI：
发表时间：
2020
期刊：
影响因子：
0
作者：
Zaika, Oleg;Tomilin, Viktor N;Pochynyuk, Oleh
通讯作者：
Pochynyuk, Oleh

A peek into Epac physiology in the kidney.

肾脏 Epac 生理学一瞥。

DOI：
发表时间：
2019
期刊：
影响因子：
0
作者：
Tomilin, Viktor N;Pochynyuk, Oleh
通讯作者：
Pochynyuk, Oleh

Modus operandi of ClC-K2 Cl- Channel in the Collecting Duct Intercalated Cells.

收集管闰细胞中 ClC-K2 Cl- 通道的操作方式。

DOI：
发表时间：
2023-01-14
期刊：
影响因子：
5.5
作者：
Stavniichuk, Anna;Pyrshev, Kyrylo;Tomilin, Viktor N;Kordysh, Mariya;Zaika, Oleg;Pochynyuk, Oleh
通讯作者：
Pochynyuk, Oleh

Polymodal roles of TRPC3 channel in the kidney.

TRPC3 通道在肾脏中的多模式作用。