Regulation of Pendrin by Angiotensin II

血管紧张素 II 对 Pendrin 的调节

• 批准号: 7988978
• 负责人: SUSAN MARIE WALL
• 金额: $ 10.31万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-12-15 至 2010-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7988978
• 关键词: Aldosterone; Alkalosis; Angiotensin II; Animals; Apical; Attenuated; Bicarbonates; Blood Pressure; Blood Vessels; Carbon Dioxide; Cell membrane; Cells; Chloride Ion; Chlorides; Colon; Deoxycorticosterone; Diet; Distal; Duct (organ) structure; Epithelial; Equilibrium; Genes; Genetic; Hypertension; Immunoblotting; Immunohistochemistry; In Vitro; Intake; Intercalated Cell; Kidney; Knockout Mice; Laboratories; Light; Measurement; Mediating; Metabolic; Microscopic; Mus; Mutant Strains Mice; Process; Production; Proteins; Proton-Translocating ATPases; Regulation; Renal tubule structure; Rodent Model; Sodium; Sodium Channel; Sodium Chloride; Syndrome; Thyroid Gland; Time; Tissues; absorption; analog; carbonate dehydratase; cytochemistry; driving force; epithelial Na+ channel; in vivo; kidney cell; mouse model; protein expression; protein transport; receptor; response; uptake

DESCRIPTION (provided by applicant): Type B intercalated cells secrete HCO3- and absorb Cl- across the apical plasma membrane through the action of the Cl-/HCO3- exchanger, pendrin. Pendrin-mediated Cl-/HCO3- exchange reduces arterial pH and HCO3- concentration, thereby attenuating a metabolic alkalosis. Pendrin-mediated Cl- absorption also contributes to the vascular volume expansion observed in rodent models of NaCl-sensitive hypertension, such as following a high NaCl diet and aldosterone analogues (deoxycorticosterone pivalate, DOCP). We have observed that the hypertension expected with DOCP administration and a high NaCl diet is not observed in mice with genetic disruption of the gene encoding pendrin (Slc26a4). The absence of aldosterone-induced hypertension in Slc26a4 null mice occurs most likely not only from the absence of pendrin-mediated Cl- uptake but also from the reduced epithelial Na+ channel (ENaC) expression observed in the kidneys of these mutant mice. However, pendrin and ENaC are regulated through both aldosterone-dependent and -independent mechanisms. Our laboratory and others have shown that angiotensin II stimulates Na+ and Cl- absorption in the cortical collecting duct (CCD) when perfused in vitro through synergy between pendrin and ENaC. How angiotensin II stimulates pendrin and ENaC expression and function and how pendrin and ENaC interact to promote NaCl absorption is the subject of the present proposal. The aims of this proposal are the following: 1) to determine the mechanism whereby angiotensin II stimulates pendrin-mediated Cl-/HCO3- exchange in vitro and to determine how ENaC and pendrin interact following angiotensin II to increase NaCl absorption, 2) to determine the mechanism of the long-term regulation of pendrin by angiotensin II in vivo and how pendrin modulates ENaC expression in vivo and 3) to determine the mechanism for the interdependency of pendrin and ENaC expression. To accomplish these objectives wild type and genetically modified mice, such as Slc26a4 (-/-), total and cell-specific AT1a (-/-), tissue-specific ENaC (-/-) and mouse models of Liddle's Syndrome, will be studied using quantitative real time PCR, light microscopic immunohistochemistry, immunogold cytochemistry and immunoblots. Transport will be studied in mouse renal tubules perfused in vitro and in cultured mouse principal cells. Whole animal studies will be employed further in balance studies and measurements of blood pressure and GFR.7. Project Narrative: Our laboratory has observed that a protein called pendrin mediates absorption of chloride by the kidney, which increases blood pressure. In addition, pendrin also regulates absorption of sodium by the kidney by changing the amount of a protein that transports sodium within the kidney (i.e. the epithelial sodium channel, ENaC). This proposal will explore how pendrin controls absorption of sodium and chloride by the kidney.

描述（由申请人提供）：B型插入细胞通过Cl-/hco3-Exchanger Pendrin的作用分泌HCO3-，并在顶端质膜上吸收Cl-。 Pendrin介导的CL-/HCO3-交换降低了动脉pH和HCO3-浓度，从而减少了代谢性碱中毒。 Pendrin介导的CL吸收也有助于在NaCl敏感的高血压的啮齿动物模型中观察到的血管体积膨胀，例如遵循高NaCl饮食和醛固酮类似物（Deoxycorticosterone pivalate，DOCP）。我们已经观察到，在遗传破坏pendrin的基因破坏（SLC26A4）的小鼠中，未观察到DOCP给药和高NaCl饮食的高血压（SLC26A4）。 SLC26A4 NULL小鼠中醛固酮诱导的高血压的不存在很可能不仅发生在没有Pendrin介导的cl摄入量，而且还来自这些突变小鼠肾脏中观察到的上皮上皮Na+通道（ENAC）的表达。然而，Pendrin和ENAC通过醛固酮依赖性和非依赖性机制受到调节。我们的实验室和其他实验室表明，血管紧张素II刺激皮质收集管（CCD）中的Na+和Cl吸收，当时通过Pendrin和ENAC之间的协同作用在体外灌注时。血管紧张素II如何刺激Pendrin，ENAC的表达和功能，以及Pendrin和ENAC如何相互作用以促进NaCl吸收是本建议的主题。 The aims of this proposal are the following: 1) to determine the mechanism whereby angiotensin II stimulates pendrin-mediated Cl-/HCO3- exchange in vitro and to determine how ENaC and pendrin interact following angiotensin II to increase NaCl absorption, 2) to determine the mechanism of the long-term regulation of pendrin by angiotensin II in vivo and how pendrin modulates ENaC expression in vivo and 3）确定Pendrin和ENAC表达相互依赖的机制。为了实现这些目标野生类型和遗传修饰的小鼠，例如SLC26A4（ - / - ），总和细胞特异性AT1A（ - / - ），组织特异性ENAC（ - / - ）以及Liddle综合征的小鼠模型，将使用定量的实时PCR，轻微的微观微观免疫组织和Immunobology cyto Cyto Cyto Cyto Cyto Cyto Cyto Cyto Cyto Cyto cy.将在体外和培养的小鼠主要细胞中灌注的小鼠肾小管中进行运输。整个动物研究将进一步用于平衡研究和血压和GFR的测量。7。 项目叙述：我们的实验室观察到一种称为Pendrin的蛋白质介导肾脏吸收氯化物，从而增加血压。此外，Pendrin还通过改变肾脏中运输钠的蛋白质（即上皮钠通道，ENAC）来调节肾脏的吸收。该提案将探讨pendrin如何通过肾脏控制钠和氯化物的吸收。