Regulation of ENaC in salt-sensitive hypertension via inflammation-induced ROS pr

描述（由申请人提供）：上皮钠通道（ENaC）是控制体液容量和血压的醛固酮敏感性远端肾单位（ASDN）中钠稳态的关键调节剂。ENaC的功能障碍和异常调节导致一系列与异常钠处理相关的疾病，范围从分别具有钠潴留和消耗的低血压到高血压，到呼吸综合征。研究ENaC在正常和病理生理中的作用可以转化为临床实践，实现NHLBI改善患者健康的使命。钠负荷与血压正常和高血压个体的血压升高相关。本提案中使用的Dahl盐敏感（SS）大鼠在高盐饮食下发生严重的高血压。我们的初步数据表明，ENaC介导的钠离子重吸收的ASDN有助于盐敏感性高血压在SS大鼠品系，我在这里假设，过量的H2 O2生产介导这种效果。与喂食低盐饮食的SS大鼠和喂食高盐饮食的consomic SS-13 BN大鼠相比，喂食高盐饮食的SS大鼠中ENaC亚基表达不适当地上调。用ENaC抑制剂苯扎明治疗减弱SS大鼠的血压升高。肾脏浸润的T淋巴细胞增加氧化应激并参与SS大鼠盐敏感性高血压的发展。此外，我们的初步结果表明，ENaC活性上调过氧化氢的生产。我推测，ENaC介导的钠离子重吸收在ASDN盐敏感性高血压的发展中发挥作用，免疫细胞的激活增加了H2 O2的产生，从而相应地激活ENaC并参与盐敏感性高血压的发展。进一步假设H2 O2产生的增加导致肌动蛋白细胞骨架的变化，并且皮质粘附素和MIM蛋白参与了这一机制。建立在我们的初步数据和以前发表的研究结果，本建议的具体目标是确定是否渗透增加H2 O2的生产在肾皮质，从而上调ENaC介导的钠重吸收在ASDN和定义H2 O2介导的ENaC活性的变化的精确机制。各种方法的组合将被用于本提案中，以提供ENaC如何被H2 O2调节的机制见解，以及该途径的变化如何导致盐诱导的高血压。这些研究将解决两个具体目的：1）确定SS大鼠中T细胞浸润和连续H2 O2产生是否增加ENaC活性; 2）确定H2 O2调节ENaC活性的细胞和分子机制。我的长期职业目标是继续我在生物医学研究领域的学术生涯，研究在细胞，器官和系统水平上参与盐和水平衡调节的离子通道。K99/R 00补助金符合我的职业目标，提供了极好的机会，帮助我过渡到 拥有NIH或其他独立研究基金的稳定的独立研究职位。

DESCRIPTION (provided by applicant): Epithelial sodium channel (ENaC) is a key regulator of sodium homeostasis in aldosterone-sensitive distal nephron (ASDN) controlling body liquid volume and blood pressure. Dysfunction and aberrant regulation of ENaC lead to a spectrum of diseases associated with abnormal sodium handling, ranging from hypo- to hypertension with sodium retention and wasting, respectively, to respiratory syndromes. The studies focused on the role of ENaC in normal and pathological physiology can be translated into clinical practice and fulfill the mission of NHLBI to improve health of the patients. Sodium loading is associated with an increase in blood pressure in normotensive and hypertensive individuals. Dahl salt-sensitive (SS) rats used in this proposal develop severe hypertension on high-salt diet. Our preliminary data indicate that ENaC-mediated Na+ reabsorption in the ASDN contributes to salt-sensitive hypertension in SS rat strain and I hypothesize here that excessive H2O2 production mediates this effect. ENaC subunits expression is inappropriately upregulated in SS rats fed a high salt diet compared to SS rats fed a low salt diet and consomic SS-13BN rats fed a high salt diet. Treatment with ENaC inhibitor benzamil attenuates increase in blood pressure in SS rats. Infiltrating T lymphocytes in the kidney increase oxidative stress and participate in the development of salt-sensitive hypertension in SS rats. Moreover, our preliminary results demonstrate that ENaC activity is upregulated by H2O2 production. I hypothesize that ENaC-mediated Na+ reabsorption in the ASDN plays a role in the development of salt-sensitive hypertension and that activation of immune cells increases generation of H2O2, which correspondingly activates ENaC and participates in the development of salt-sensitive hypertension. It is further hypothesized that increased H2O2 production results in changes of the actin cytoskeleton and that cortactin and MIM proteins are involved in this mechanism. Built upon our preliminary data and previously published findings, the specific objectives of this proposal are to determine whether infiltration increases H2O2 production in the kidney cortex and consequently upregulates ENaC-mediated sodium reabsorption in the ASDN and define the precise mechanisms of H2O2-mediated changes in ENaC activity. A combination of variety approaches will be used in this proposal to provide mechanistic insights on how ENaC is regulated by H2O2 and how changes in this pathway contribute to salt-induced hypertension. These studies will address two Specific Aims: 1) To determine if infiltration of T cells and consecutive H2O2 production in SS rats increases ENaC activity; 2) To define the cellular and molecular mechanism by which H2O2 modulates ENaC activity. My long-term professional goal is to continue my academic career in the field of biomedical research to study ion channels involved in regulation of salt and water balance at the cellular, organ and systemic levels. The K99/R00 grant fits to my career goals providing excellent opportunity to assist in transitioning to a stable independent research position with NIH or other independent research funding.