Two-Pore Domain Potassium Channels and Aldosterone Secretion

双孔域钾通道和醛固酮分泌

• 批准号: 7464697
• 负责人: PAULA Q BARRETT
• 金额: $ 45.84万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-03 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7464697
• 关键词: Acids; Adrenal Glands; Aldosterone; Aldosterone Receptors; Angiotensin II; Animal Experimentation; Bathing; Calcium; Cardiovascular system; Cells; Cellular biology; Chronic Kidney Failure; Condition; Data; Diet; Disease; Disease Progression; Electrophysiology (science); Equilibrium; Excretory function; Family; Financial compensation; Generations; Genetic; Heart failure; Homeostasis; Hormonal; Hypertension; Immunohistochemistry; In Situ Hybridization; In Vitro; Infusion procedures; Kidney; Knock-out; Knockout Mice; Mediating; Membrane; Membrane Potentials; Membrane Proteins; Metabolic; Mineralocorticoid Receptor; Molecular; Mus; Patients; Physiological; Potassium; Potassium Channel; Primary Hyperaldosteronism; Production; Property; Pump; Regulation; Renin; Research; Resistance; Rest; Role; Serum; Slice; Sodium Chloride; Stimulus; System; T-Type Calcium Channels; Testing; Tissues; Water; Work; Zona Glomerulosa; candesartan; congenic; deprivation; early onset; extracellular; in vivo; mature animal; mouse model; novel; patch clamp; receptor; response; salt balance; steroid hormone; therapeutic target; tool; urinary; voltage

DESCRIPTION (provided by applicant): Aldosterone is an early-onset pathogenic stimulus that adversely influences cardiovascular and renal homeostasis. It is elevated in heart failure, chronic kidney disease and some forms of hypertension. Although the production of aldosterone in vivo has long been known to be regulated by Ang I and potassium, the contribution of K channel regulation to the physiological actions of Ang II, though hypothesized, has remained unproven. The recent generation of TASK-1, TASK-3, and TASK-1/TASK-3 knockout mice offers the exciting possibility to establish the functional importance of TASK channel regulation to the physiological control of aldosterone production in vivo. Our hypothesis that TASK subunits contribute to background K currents and the control of membrane potential by Ang II and acidification in the aldosterone secreting adrenal zona glomerulosa (ZG) cells is tested in vitro. Moreover, the hypothesis that these channels are important in the regulation of aldosterone production and salt/water balance in vivo is determined under basal conditions and during hormonal and metabolic challenge (i.e., AngII infusion, Na loading and deprivation). We pursue the following specific aims: Aim 1: Generate and validate novel conventional and conditional TASK channel subunit knockout mouse lines using qRT-PCR, in situ hybridization, and immunohistochemistry; Aim 2: Determine membrane properties of ZG cells in control and TASK channel knockout mice, characterizing background K channel currents and their modulation by AngII, extracellular K and bath pH, and evaluating the role of these channels in setting membrane voltage and supporting ZG cell excitability; Aim 3: Evaluate the importance of TASK channel expression to the control of aldosterone production in vivo in control and TASK channel knockout mice determining: the steady-state aldosterone secretory response to RAAS suppression caused by dietary manipulation of salt balance, and the aldosterone secretory response to the delivery of exogenous AngII or acid loading in vivo. The strength of this proposal lies in the combined use of molecular and cell biology, electrophysiology and whole animal experimentation. Minimally, our efforts will clarify the role of TASK channels in the production of aldosterone. Optimally, our work will identify a new target for the therapy of patients with heart failure, chronic kidney disease and resistant hypertension. Project Narrative: Idiopathic primary hyperaldosteronism (IHA) is present in 13% of non-selected hypertensive patients and rises to 20% among those that have resistant hypertension. Using a combination of cellular and in vivo approaches our studies identify TASK K channels as critical membrane proteins that control the production of aldosterone, the steroid hormone that is elevated in IHA. The identification of this target can be used to generate a useful therapy for patients with IHA but also for patients with heart failure and chronic kidney disease where elevated aldosterone also hastens disease progression.

描述（由申请人提供）：醛固酮是一种早期发作的致病性刺激，对心血管和肾稳态产生不利影响。它的心力衰竭，慢性肾脏疾病和某些形式的高血压升高。尽管长期以来，众所周知，醛固酮在体内的生产受ANG I和钾的调节，但K通道调节对ANG II的生理作用的贡献虽然假设，但仍未得到证实。最近一代任务1，Task-3和Task-1/Task-1/Task-3淘汰赛小鼠提供了令人兴奋的可能性，以确立任务渠道调节对体内醛固酮产生的生理控制的功能重要性。我们的假设是，任务亚基有助于背景K电流以及ANG II的膜电位以及分泌肾上腺Zona glomerulosa（ZG）细胞的酸化的控制。此外，在基础条件下以及激素和代谢挑战期间（即Angii输注，NA载荷和剥夺）确定了这些通道在体内醛固酮产生和盐/水平平衡中至关重要的假设。我们追求以下特定目的：目标1：使用QRT-PCR，原位杂交和免疫组织化学生成并验证新型的常规和条件任务通道亚基敲除小鼠线； AIM 2：确定ZG细胞在对照和任务通道敲除小鼠中的膜特性，表征背景K通道电流及其通过ANGII，细胞外K和BATH pH的调节，并评估这些通道在设置膜电压和支持ZG细胞兴奋性方面的作用；目标3：评估任务渠道表达对控制和任务通道敲除小鼠体内醛固酮产生的重要性的重要性：稳态醛固酮分泌的反应对RAAS抑制盐平衡引起的RAAS抑制，以及醛固酮分泌对外源性Angii Angii或Invivo的降解的反应。该建议的强度在于分子和细胞生物学，电生理学和整个动物实验的联合使用。最少的努力将阐明任务渠道在醛固酮生产中的作用。最佳地，我们的工作将确定对心力衰竭，慢性肾脏疾病和耐药性高血压治疗的新目标。 项目叙事：特发性原发性催眠醛酸（IHA）存在于13％的非选拔高血压患者中，并且患有耐药性高血压的患者中升至20％。通过结合细胞和体内方法，我们的研究将任务K通道确定为关键的膜蛋白，可控制醛固酮的产生，醛固酮是IHA中升高的类固醇激素。该靶标的鉴定可用于为IHA患者以及心力衰竭和慢性肾脏疾病的患者产生有用的疗法，升高的醛固酮也会加速疾病的进展。