2-pore-domain K+ channels as novel targets for modulating islet hormone secretion

2孔域K通道作为调节胰岛激素分泌的新靶点

• 批准号: 9112994
• 负责人: David Aaron Jacobson
• 金额: $ 35.8万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9112994
• 关键词: Ablation; Accounting; Action Potentials; Alpha Cell; Animal Disease Models; Animals; Blood Glucose; Cell membrane; Cell physiology; Cells; Coupled; Coupling; Data; Diabetes Mellitus; Disease; Dominant-Negative Mutation; Fire - disasters; Glucagon; Glucose; Goals; Hand; Health; High Fat Diet; Hormones; Human; Hyperglycemia; Hyperinsulinism; Insulin; Ion Channel; Islet Cell; Islets of Langerhans; Knowledge; Lead; Medical; Membrane Potentials; Mission; Molecular; Mus; Non-Insulin-Dependent Diabetes Mellitus; Pathogenesis; Patients; Pharmacology; Physiological; Play; Population; Potassium; Potassium Channel; Proteins; Public Health; Research; Role; Stress; Testing; Therapeutic; Transgenic Mice; Work; base; blood glucose regulation; insight; insulin secretion; islet; mouse model; new therapeutic target; novel; therapeutic target; voltage

DESCRIPTION (provided by applicant): Insulin and glucagon secretion are disrupted in patients with type-2 diabetes mellitus (T2DM) and in animal models of the disease, which is due in part to perturbations in islet-cell membrane potential (�?p) and Ca2+ entry. While ion channels that regulate excitability are key regulators of Ca2+ influx, there is a gap in our understanding of the background potassium currents that stabilize the �?p from where action potentials fire during glucose stimulation. Existence of this gap represents an important problem because, until it is filled, our understanding of glucagon and insulin secretion is incomplete, which limits the therapeutic targets that can be utilized for treating dysglycemia. The long term goal of this research is to understand physiological and pathophysiological islet hormone secretion in the context of "leak" two-pore-domain (K2P) potassium channel activity. The overall objective of this proposal, which is the next step toward attainment of the long term goal, is to elucidate molecular mechanisms regulating secretagogue dependent modulation of islet Ca2+ influx and hormone secretion via K2P channels. This project will test the central hypothesis that K2P channels modulate the islet-cell membrane potential (�?p), thus, regulating Ca2+ influx and hormone secretion. This hypothesis has been formulated from preliminary data that finds that the K2P channels TASK-1 and TASK-3 regulate glucose stimulated �-cell �?p, Ca2+ influx, and insulin secretion. Further data find that the K2P channel TREK-2 is expressed in islet �-cells where it modulates electrical activity and glucagon secretion. The rationale that underlies the proposed research is that understanding how blood glucose is influenced by islet-cell K2P channel activity will expose new therapeutic targets for treating diabetes. Guided by strong preliminary data, this hypothesis will be tested by pursuing two specific aims: 1) Determine the influence of K2P channels on islet �-cell insulin secretion; and 2) Determine the role that K2P channels play in limiting islet �-cell excitability and glucagon secretion. Under the first aim, mie with inducible �-cell ablation of TASK-1 andTASK-3, which are already on hand, will be utilized to test the influences of these channels on mouse glucose homeostasis. The function of human �-cell TASK channels will also be assessed with specific and potent pharmacology and a dominant negative (D/N) approach, which have been established as feasible in the applicants' hands. Finally, the influence of TASK channels on �-cell function under stress will be assessed in animals treated with a high fat diet. Under the second aim, transgenic mice with fluorescent protein expressing �-cells that are deficient for TREK- 2, which are on hand, will be utilized to assess the roles of these channels during �-cell glucagon secretion. An �-cell specific D/N approach, which has been validated, will also be utilized to assess the function of human �- cell TREK-2 channels. The proposed research is significant because it is the first step in a continuum of research that is expected to lead to pharmacological strategies for regulating insulin and glucagon secretion; it is essential for uncovering therapies for treating dysglycemia in diseases such as T2DM and hyperinsulinemia.

描述（由适用提供）：2型糖尿病（T2DM）和该疾病的动物模型中，胰岛素和胰高血糖素的分泌受到破坏，这部分归因于胰岛细胞膜电位（�？P）和Ca2+进入的扰动。虽然调节兴奋性的离子通道是CA2+影响的关键调节剂，但我们对背景钾电流的理解存在差距，这些钾电流从葡萄糖刺激期间动作电位发射的地方稳定了降低。这种差距的存在代表了一个重要的问题，因为在填补之前，我们对胰高血糖素和胰岛素分泌的理解是不完整的，这限制了可用于治疗血糖症的治疗靶标。这项研究的长期目标是在“泄漏”两孔域（K2P）钾通道活动的背景下了解生理和病理生理胰岛分泌。该提案的总体目的是迈向长期目标的下一步，是阐明通过K2P通道对胰岛CA2+影响和Horsene分泌的分子机制。该项目将测试中心假设，即K2P通道调节胰岛膜电位（�？P），因此调节Ca2+影响力和horsene分泌。该假设是从初步数据提出的，该数据发现K2P通道任务1和Task-3调节葡萄糖刺激了``细胞''？p，Ca2+影响和胰岛素分泌。进一步的数据发现，K2P通道TREK-2在调节电活动和臀部分泌的胰岛中表达。拟议的研究基础的基本原理是，了解血糖如何受到胰岛K2P通道活动的影响将暴露于治疗糖尿病的新疗法靶标。在强大的初步数据的指导下，将通过追求两个具体目的来检验该假设：1）确定K2P渠道对胰岛胰岛素分泌的影响； 2）确定K2P通道在限制胰岛中的作用 - 令人兴奋和臀部分泌。在第一个目的下，将使用诱导型``task-1 andTask-3）的MIE（现有的）将其用于测试这些通道对小鼠葡萄糖稳态的影响。人类 - 细胞任务渠道的功能也将通过特定和潜在的药理学以及主要的负面（D/N）方法进行评估，这些方法已确定为申请人手中可行的。最后，将在用高脂肪饮食治疗的动物中评估任务通道对压力下的细胞功能的影响。在第二个目标下，将使用表达荧光蛋白表达的荧光蛋白的转基因小鼠在手头的TREK-2中，将用于评估这些通道在 - 细胞胰高血糖素分泌过程中的作用。经过验证的细胞特异性D/N方法也将用于评估人类Trek-2通道的功能。拟议的研究之所以重要，是因为它是一项连续研究的第一步，预计会导致控制胰岛素和亚麻分泌的药物策略。这对于发现在T2DM和高胰岛素血症等疾病中治疗血糖治疗糖血糖的疗法至关重要。