Two-Pore-Domain Potassium Channels as Novel Targets for Modulating Islet Hormone Secretion

双孔域钾通道作为调节胰岛激素分泌的新靶点

基本信息

批准号：
10408705
负责人：
David Aaron Jacobson
金额：
$ 39.58万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-08-01 至 2023-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10408705
关键词：
Ablation Alpha Cell Animal Disease Models Beta Cell Cell physiology Cells Cellular Stress Charge Code Coupled Coupling Data Diabetes Mellitus Disease Dominant-Negative Mutation Endoplasmic Reticulum Failure Functional disorder Genes Genetic Polymorphism Glucagon Glucose Goals Hand Health Heterodimerization Homeostasis Hormone secretion Human Hyperglycemia Hypoglycemia In Vitro Insulin Insulin-Dependent Diabetes Mellitus Ion Channel Islet Cell Islets of Langerhans Knowledge Measures Membrane Mitochondria Molecular Monitor Mus Non-Insulin-Dependent Diabetes Mellitus Pancreas Pathogenesis Patients Pharmacology Phenotype Physiological Play Potassium Channel Predisposition Proteins Regulation Research Research Project Grants Risk Rodent Role Stress Testing Therapeutic Time Transgenic Mice Work biological adaptation to stress blood glucose regulation controlled release diabetes pathogenesis diabetic driving force endoplasmic reticulum stress gain of function in vivo insight insulin secretion islet knock-down new therapeutic target novel prevent response small hairpin RNA therapeutic target voltage

项目摘要

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 Ca2+ homeostasis. While two-pore- domain K+ (K2P) channels are key regulators of pancreatic islet-cell Ca2+ handling and hormone secretion, there is a gap in our understanding of how these channels control human islet function and dysfunction under diabetic conditions. The long term goal of this research is to determine the therapeutic potential of targeting K2P channels for treating diabetes and preventing -cell destruction. The overall objective of this project is to elucidate molecular mechanisms regulating secretagogue dependent modulation of islet Ca2+ influx and hor- mone secretion via K2P channels. This project will test the central hypothesis that human islet K2P channels modulate cytoplasmic and endoplasmic reticulum Ca2+ handling, thus, regulating hormone secretion as well as the -cell ER-stress response under diabetic conditions. This project is supported by strong preliminary data that has identified TALK-1 as an important determinant of human and rodent -cell ER Ca2+ handling, mito- chondrial function, and insulin secretion. Further data that has determined that the TALK-1 related channel TALK-2 also controls ER Ca2+ homeostasis and is highly expressed in human islets. Finally, preliminary data finds that the K2P channels, TASK-1 and TALK-2, control -cell ER Ca2+ storage and glucagon secretion. The rationale that underlies the proposed research is that understanding how islet hormone secretion is influenced by K2P channel activity will expose novel therapeutic targets for reducing -cell failure and hyperglycemia dur- ing the pathogenesis of T2DM. This project will be accomplished with the following two specific aims: 1) De- termine how TALK-1 and TALK-2 channels modulate -cell function and dysfunction over time and under stress; and 2) Determine how TASK-1 and TALK-2 channels control of pancreatic -cell glucagon secretion. Under the first aim, the function of human-cell TALK channels will be assessed with a dominant negative (D/N) and ShRNA approach, which have been established as feasible in the applicants’ hands. Moreover, mice with inducible -cell ablation of TALK-1 will be utilized to test the influences of these channels on glucose ho- meostasis. The roles of -cell TALK channels will be assessed under physiological conditions as well as under the stressful conditions associated with diabetes in vivo and/or in vitro. Under the second aim, transgenic mice deficient for TASK-1 as well as a -cell specific D/N and ShRNA approaches will be utilized to assess the roles of TASK-1 during human and mouse -cell Ca2+ handling and glucagon secretion. Finally, TALK-2 channel control of human -cell function will be determined with islet-cell selective D/N and knockdown to monitor their impact on Ca2+ homeostasis and glucagon secretion. This project is significant because it is expected to illumi- nate pharmacological strategies for regulating insulin and glucagon secretion as well as reducing -cell ER- stress; it is essential for uncovering therapies for treating dysglycemia and reducing -cell failure in T2DM.

2 型糖尿病 (T2DM) 患者和动物的胰岛素和胰高血糖素分泌受到干扰该疾病的模型，部分原因是胰岛细胞 Ca2+ 稳态的扰动。结构域 K+ (K2P) 通道是胰岛细胞 Ca2+ 处理和激素分泌的关键调节因子，我们对这些通道如何控制人类胰岛功能和功能障碍的理解存在差距这项研究的长期目标是确定靶向治疗的潜力。用于治疗糖尿病和预防  细胞破坏的 K2P 通道该项目的总体目标是阐明调节胰岛 Ca2+ 流入和激素依赖促分泌素调节的分子机制通过 K2P 通道分泌胰岛素该项目将测试人类胰岛 K2P 通道的中心假设。调节细胞质和内质网 Ca2+ 处理，从而调节激素分泌以及糖尿病条件下  细胞 ER 应激反应该项目得到了强有力的初步数据的支持。已确定 TALK-1 是人类和啮齿动物  细胞 ER Ca2+ 处理、线粒体的重要决定因素进一步的数据已确定TALK-1相关通道。 TALK-2 还控制 ER Ca2+ 稳态，并在人类胰岛中高度表达。最后，初步数据。发现 K2P 通道 TASK-1 和 TALK-2 控制 α 细胞 ER Ca2+ 储存和胰高血糖素分泌。拟议研究的基本原理是了解胰岛激素分泌是如何受到影响的 K2P 通道活性将揭示减少  细胞衰竭和高血糖的新治疗靶点该项目将通过以下两个具体目标来完成：1) De- 确定 TALK-1 和 TALK-2 通道如何随着时间和时间的推移调节  细胞功能和功能障碍压力；和 2) 确定 TASK-1 和 TALK-2 如何控制胰腺 α 细胞胰高血糖素的分泌。在第一个目标下，人类  细胞 TALK 通道的功能将通过显性负性评估 (D/N) 和 ShRNA 方法，这些方法在申请人手中已被确定为可行。 TALK-1 的诱导型  细胞消融将用于测试这些通道对葡萄糖的影响细胞转移中的作用将在生理条件下以及在第二个目标是转基因小鼠体内和/或体外与糖尿病相关的应激条件。 TASK-1 缺陷以及 α 细胞特异性 D/N 和 ShRNA 方法将用于评估作用 TASK-1 在人和小鼠 α 细胞 Ca2+ 处理和胰高血糖素分泌过程中的作用最后，TALK-2 通道。人类α细胞功能的控制将通过胰岛细胞选择性D/N和敲低来确定，以监测其对 Ca2+ 稳态和胰高血糖素分泌的影响该项目意义重大，因为它有望阐明。调节胰岛素和胰高血糖素分泌以及减少  细胞 ER- 的天然药理学策略压力；这对于发现治疗血糖异常和减少 T2DM 中  细胞衰竭的疗法至关重要。