Role of PON3 in regulating renal Na+ and K+ homeostasis

PON3 在调节肾钠钾稳态中的作用

• 批准号: 10693407
• 负责人: Shujie Shi
• 金额: $ 31.8万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-15 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10693407
• 关键词: Address; Affect; Aldosterone; Amiloride; Apical; Arylesterase; Biological Models; Biotinylation; Blood; Blood Pressure; Caenorhabditis elegans; Cell Line; Cells; Data; Diet; Dietary Potassium; Distal; Distal convoluted renal tubule structure; Duct (organ) structure; Endoplasmic Reticulum; Extracellular Fluid; Family; Genetic Transcription; Homeostasis; Hypertension; Hypokalemia; Hypotensives; Immunofluorescence Immunologic; Intake; Intercalated Cell; Ion Channel; Kidney; Knockout Mice; Measures; Mediating; Metabolic; Molecular Chaperones; Monitor; Mus; Natriuresis; Nephrons; Neurons; Patch-Clamp Techniques; Pathway interactions; Pattern; Phosphorylation; Physiological; Potassium; Potassium Channel; Property; Proteins; Publishing; Radio; Rattus; Regional Perfusion; Regulation; Renal function; Role; SLC12A3 gene; Side; Sodium; Sodium Chloride; Stains; Substrate Specificity; Surface; Telemetry; Tissues; Touch sensation; Ubiquitination; Water; Western Blotting; Work; absorption; aryldialkylphosphatase; blood pressure control; blood pressure regulation; cell type; dietary salt; differential expression; driving force; epithelial Na+ channel; extracellular; hyperkalemia; in vivo; large-conductance calcium-activated potassium channels; member; multicatalytic endopeptidase complex; new therapeutic target; novel; receptor; symporter

ABSTRACT The mammalian paraoxonase (PON) family consists of three highly conserved members (PON1, PON2 and PON3) with unique anti-oxidative and anti-atherosclerotic properties. PON1 and 2 have been implicated in blood pressure (BP) regulation. While the role of PON3 in regulating BP has not been investigated, it is expressed in the aldosterone-sensitive distal nephron where the fine tuning of Na+ absorption and K+ secretion occurs. PONs share key structural and functional features with MEC-6, an endoplasmic reticulum-resident chaperone of C. elegans. MEC-6 is required for proper folding, assembly, and surface expression of the mechanosensitive degenerin channel in touch receptor neurons. The chaperon function is conserved between mammalian PONs and C. elegans MEC-6. We have previously shown that both PON2 and PON3 regulate functional expression of the epithelial Na+ channel (ENaC), a member of the ENaC/degenerin family of ion channels. ENaC mediates the rate-limiting step of Na+ reabsorption in distal nephron and has a key role in volume and BP control. While the constitutive K+ secretion is conducted by the renal outer medullary K+ (ROMK) channels, ENaC-dependent and flow-induced K+ secretion is mediated by the large conductance K+ (BK) channels. In the preliminary studies, we found that Pon3 KO mice have higher ENaC activity and enhanced amiloride-sensitive natriuresis, suggesting ENaC functional expression is upregulated in the absence of PON3. In addition, we have identified BK channel as a novel target of PON3. When expressed in HEK293 cells, PON3 interacted with BK α subunit to reduce its surface expression and channel activity. Our proposed studies will define mechanisms by which PON3 functions as a chaperone in the regulation of ENaC and BK expression. We will determine the consequences of deleting PON3 in renal Na+ and K+ handling and BP control in mice. Successful completion our proposed studies will enhance our understanding of the mechanisms by which PONs function as chaperones and their physiological roles in kidney function and BP control.

摘要 哺乳动物对氧磷酶（PON）家族由三个高度保守的成员（PON 1， PON 2和PON 3）具有独特的抗氧化和抗动脉粥样硬化特性。PON 1和2 与血压（BP）调节有关。而PON 3在调节血压中的作用 尚未研究过，它表达在醛固酮敏感的远端肾单位中，其中 发生Na+吸收和K+分泌的微调。脑桥共享关键的结构和功能 MEC-6是C.优雅的MEC-6是 机械敏感性变性蛋白的正确折叠、组装和表面表达所需的 触觉感受器神经元中的通道。伴侣蛋白功能在哺乳动物之间是保守的， 脑桥和C. elegans MEC-6.我们以前已经表明，PON 2和PON 3都调节 上皮Na+通道（ENaC）的功能表达，ENaC/变性蛋白 离子通道家族ENaC介导远端肾单位Na+重吸收的限速步骤 并在容量和BP控制中起关键作用。而组成型K+分泌是由 肾外髓K+（ROMK）通道，ENaC依赖性和流量诱导的K+分泌 由大电导K+（BK）通道介导。在初步研究中，我们发现， Pon 3 KO小鼠具有更高的ENaC活性和增强的阿米洛利敏感性尿钠排泄， 表明ENaC功能表达在PON 3不存在下上调。另外我们 已经确定BK通道是PON 3的新靶点。当在HEK 293细胞中表达时，PON 3 与BK α亚基相互作用，降低其表面表达和通道活性。我们提出的 研究将确定PON 3作为伴侣蛋白在调节 ENaC和BK表达。我们将确定在肾Na+中删除PON 3的后果。 以及小鼠中K+处理和BP控制。我们建议的研究若能顺利完成， 我们对脑桥作为分子伴侣的作用机制及其 在肾功能和血压控制中的生理作用。