Mechanisms and Consequences of Defective Flow-Induced Potassium Secretion in the Metabolic Syndrome

代谢综合征中血流诱导钾分泌缺陷的机制和后果

• 批准号: 10202571
• 负责人: VIVEK BHALLA
• 金额: $ 41.55万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-15 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10202571
• 关键词: Acute; Affect; Aldosterone; American; Arrhythmia; Blood; Calcium; Cardiovascular Diseases; Cardiovascular system; Cell Fractionation; Diet; Dietary Potassium; Disease; Distal; Diuretics; Duct (organ) structure; Equilibrium; Excretory function; Fatty acid glycerol esters; Feedback; Functional disorder; Furosemide; General Population; Goals; Grant; H(+)-K(+)-Exchanging ATPase; High Fat Diet; Immunoblotting; Immunofluorescence Immunologic; Impairment; Incidence; Individual; Insulin; Insulin Receptor; Insulin Resistance; Insulin deficiency; Ion Channel; KCNJ1 gene; Kidney; Knockout Mice; Learning; Life; MAP Kinase Gene; MAPK3 gene; Measures; Mediating; Metabolic syndrome; Methodology; Methods; Modeling; Mus; Nephrons; Neurons; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Outcome; Patients; Pharmacologic Substance; Pharmacology; Phenocopy; Phosphorylation; Phosphotransferases; Plasma; Potassium; Predisposition; Preparation; Prevention; Preventive; Pump; Reagent; Receptor Signaling; Regulation; Research; Research Personnel; Resources; Role; Signal Pathway; Signal Transduction; Signaling Protein; Sodium; Stretching; Sum; Syndrome; Techniques; Testing; Therapeutic; Tubular formation; United States National Institutes of Health; Urine; Vascular Smooth Muscle; Vasopressins; Wild Type Mouse; cell type; collecting tubule structure; dietary; high risk; hyperkalemia; iberiotoxin; in vivo; innovation; insulin secretion; insulin signaling; large-conductance calcium-activated potassium channels; mortality; mouse model; novel; patient subsets; paxilline; protein expression; receptor; response; uptake; voltage

PROJECT SUMMARY / ABSTRACT: The metabolic syndrome affects 50 million Americans, and is associated with obesity and insulin resistance. Hyperkalemia is associated with life-threatening cardiac arrhythmias and increased mortality, and patients with insulin resistance and Type 2 diabetes are susceptible to hyperkalemia. However, potential derangements in renal potassium (K) handling remain unexplored. As part of our ongoing NIH-sponsored studies of ion channel function in insulin resistance, we, the Investigators (PI and Co-I), uncovered that flow-induced K secretion (FIKS) in the distal nephron, mediated by BK channels, and renal K handling is defective. Deletion of BK channels leads to defective renal K handling, and impaired K adaptation. The objective of this proposal is to determine the mechanisms underlying the reduction in BK channel- mediated FIKS in the distal nephron and to determine the consequences for K adaptation and hyperkalemia in the insulin resistance syndrome. The R01 Grant will provide the necessary resources to test the hypothesis that insulin resistance in the distal nephron is a phenocopy for BK channel deficiency with decreased insulin signaling leading to disrupted BK channel activity, and thus, defective FIKS and K adaptation, and predisposition to hyperkalemia. To test this hypothesis, we propose two specific aims. Aim #1 is to determine the cellular mechanisms of distal nephron BK channel dysfunction in a mouse model of insulin resistance. Using control and insulin resistant mice, we will measure expression and subcellular localization of distal nephron BK and Ca2+- channels using two innovative methodologies, and will study the Ca2+ and voltage sensitivity of BK channels. We will also measure the impact of defective BK channels on K adaptation and hyperkalemia in the metabolic syndrome. Aim #2 is to determine whether impaired insulin receptor signaling in the distal nephron is sufficient to phenocopy the BK channel dysfunction of insulin resistance. Using a novel renal tubular insulin receptor knockout mouse, we will measure BK and Ca2+ channel expression, and subcellular localization using similar methods to Aim #1. We will study the Ca2+ and voltage sensitivity of BK channels in control and knockout mice and will measure the effect of deletion of insulin receptor signaling on K adaptation and hyperkalemia. We will also measure cell signaling pathways related to insulin and BK channels. We anticipate that these results will significantly advance the field by identifying appropriate dietary and pharmaceutical targets for the prevention and treatment of hyperkalemia in diseases associated with insulin resistance, such as obesity and Type 2 diabetes mellitus. The proposed research is innovative in that we will directly study the regulation of renal BK channels in insulin resistance and will employ novel reagents and cutting-edge techniques to understand the consequences of defective FIKS for hyperkalemia. Through the proposed studies, we will also learn about mechanisms of insulin signaling in the kidney in the insulin resistance syndrome and the role of diet in determining cardiovascular outcomes in this syndrome.

项目概要/摘要：代谢综合征影响着5000万美国人， 肥胖和胰岛素抵抗。高钾血症与危及生命的心律失常有关， 死亡率增加，胰岛素抵抗和2型糖尿病患者易患高钾血症。 然而，肾钾（K）处理的潜在紊乱仍未探索。作为我们正在进行的 NIH申办的胰岛素抵抗中离子通道功能的研究，我们，研究者（PI和Co-I）， 揭示了由BK通道介导的远端肾单位中的流动诱导的K分泌（FIKS）， 处理有缺陷。BK通道的缺失导致肾K处理缺陷和K适应受损。 本提案的目的是确定BK通道减少的潜在机制- 介导的FIKS在远端肾单位，并确定后果的K适应和高钾血症， 胰岛素抵抗综合征R 01赠款将提供必要的资源来测试假设 远端肾单位的胰岛素抵抗是BK通道缺陷伴胰岛素减少的表型 导致BK通道活性中断的信号传导，从而导致有缺陷的FIKS和K适应，以及 易患高钾血症。为了验证这一假设，我们提出了两个具体目标。目标#1是确定 胰岛素抵抗小鼠模型中远端肾单位BK通道功能障碍的细胞机制。 使用对照和胰岛素抵抗小鼠，我们将测量远端胰岛素受体的表达和亚细胞定位。 肾单位BK和Ca 2+通道使用两种创新的方法，并将研究Ca 2+和电压 BK通道的灵敏度。我们还将测量有缺陷的BK通道对K适应的影响， 代谢综合征中的高钾血症目标2是确定胰岛素受体信号传导是否受损 远端肾单位足以复制胰岛素抵抗的BK通道功能障碍。使用一种新 肾小管胰岛素受体敲除小鼠，我们将测量BK和Ca 2+通道表达， 使用与目标#1类似的方法进行亚细胞定位。我们将研究BK细胞的钙离子敏感性和电压敏感性 在对照和敲除小鼠中检测胰岛素受体通道，并将测量胰岛素受体信号转导缺失对K 适应和高钾血症。我们还将测量与胰岛素和BK通道相关的细胞信号通路。 我们预计，这些结果将显着推进该领域确定适当的饮食和 用于预防和治疗胰岛素相关疾病中的高钾血症的药物靶标 抵抗力，如肥胖和2型糖尿病。这项研究是创新的，我们将 直接研究胰岛素抵抗中肾BK通道的调节，并将采用新的试剂， 尖端技术来了解有缺陷的FIKS对高钾血症的后果。通过 建议的研究，我们还将了解胰岛素信号在肾脏中的机制， 抵抗综合征和饮食在决定该综合征心血管结局中的作用。