Facilitated insulin secretion via ablation of a compartmentalized pool of PIP2

通过消融 PIP2 区室库促进胰岛素分泌

• 批准号: 7697935
• 负责人: Oladapo O Yeku
• 金额: $ 2.83万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7697935
• 关键词: Ablation; Actins; Acute; Address; Animal Model; Biological Process; Calcium; Calcium Channel Agonists; Calcium Signaling; Cells; Cytoskeletal Modeling; Enzymes; Epidemic; Event; Generations; Glucose; Glucose tolerance test; Goals; Insulin; Islet Cell; Islets of Langerhans; Lipids; Measurement; Methods; Modeling; Mus; National Research Service Awards; Non-Insulin-Dependent Diabetes Mellitus; Pathway interactions; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phosphotransferases; Play; Potassium; Potassium Channel; Process; RNA Interference; Reagent; Research; Resistance; Role; Signal Transduction; Small Interfering RNA; Testing; Therapeutic; Transgenic Mice; United States; channel blockers; diabetic; diabetic patient; expectation; insulin secretion; novel; phosphatidylinositol 4-phosphate; public health relevance; research study; response

DESCRIPTION (provided by applicant): The most common form of Type II diabetes, which is epidemic in the United States, initiates from target cell resistance to insulin combined with inadequate pancreatic islet ¿-cell insulin secretion. Lipid signaling plays key roles in the pathway that controls insulin secretion. My sponsor's lab and I have generated preliminary evidence that the lipid signaling enzyme phosphatidylinositol 4-phosphate 5-Kinase a (PI4P5Ka), which generates phosphatidylinositol 4,5 bisphosphate (PIP2), restricts regulated insulin secretion; hence inhibiting this signaling enzyme may present a potential therapeutic opportunity. PIP2 functions in multiple cell biological processes. The initial goal of this NRSA application is to delineate the mechanisms through which PI4P5Ko>generation of PIP2 inhibits insulin secretion, including examining calcium signaling and actin cytoskeletal reorganization in pancreatic islet cells in response to glucose challenge, since there is precedent for PIP2 involvement in these events, and they are key to the secretory process. In the second goal, I will develop an animal model to test whether acutely decreasing PI4P5Ka in pancreatic islet ¿ -cells using RNAi constitutes a potential approach that could benefit Type II diabetic patients. Aim 1: To establish the mechanism via which PI4P5Ka inhibition leads to increased insulin release. I will explore whether the facilitation of insulin release via PI4P5Ka inhibition is dependent on dynamic changes in the actin cytoskeletal mesh, or whether there is involvement at the level of calcium or potassium signaling. These experiments will be addressed by employing actin stabilizing and destabilizing reagents, calcium channel activators, and K+ channel blockers. Aim 2: To determine if acute elimination of PI4P5Ka ameliorates Type II diabetes. Using a novel method, transgenic mice that can undergo conditional silencing of PI4P5Ka in their pancreatic islets will be generated and crossed with hypoinsulinemic Type ll-predisposed mice. Glucose tolerance tests and insulin measurements will be performed before and after transient or long-term Pl4P5Ka silencing. The results will model the expectations for pharmacological inhibition of PI4P5Ka in type ll-diabetic patients using siRNA approaches. PUBLIC HEALTH RELEVANCE: This research aims to provide an alternative therapeutic approach to the management of Type II diabetes.

描述（由申请人提供）：最常见的 II 型糖尿病在美国流行，起因于靶细胞对胰岛素的抵抗以及胰岛功能不足 ¿脂质信号传导在控制胰岛素分泌的途径中发挥着关键作用，我和资助者的实验室已经获得了脂质信号传导酶磷脂酰肌醇 4-磷酸 5-激酶 a (PI4P5Ka) 的初步证据，该酶可生成磷脂酰肌醇 4,5。双磷酸盐 (PIP2) 限制胰岛素分泌；因此抑制这种信号酶可能提供潜在的治疗机会。该 NRSA 应用的最初目标是描绘 PI4P5Ko> 生成 PIP2 抑制胰岛素分泌的机制，包括检查胰岛细胞响应葡萄糖挑战的钙信号传导和肌动蛋白细胞骨架重组。 PIP2 参与这些事件的先例，它们是分泌过程的关键。在第二个目标中，我将开发一个动物模型来测试 PI4P5Ka 是否急剧减少。胰岛 ¿目标 1：建立 PI4P5Ka 抑制导致胰岛素释放增加的机制，我将探讨通过 PI4P5Ka 抑制促进胰岛素释放是否依赖于动态变化。这些实验将通过使用肌动蛋白稳定和去稳定试剂、钙通道来解决。目标 2：为了确定 PI4P5Ka 的快速消除是否可以改善 II 型糖尿病，将产生能够在胰岛中进行 PI4P5Ka 条件性沉默的转基因小鼠，并与低胰岛素 II 型糖尿病进行杂交。易感小鼠将在短暂或长期 Pl4P5Ka 沉默之前和之后进行葡萄糖耐量测试和胰岛素测量。将使用 siRNA 方法对 II 型糖尿病患者中 PI4P5Ka 的药理学抑制作用进行建模。 公共健康相关性：本研究旨在为 II 型糖尿病的管理提供替代治疗方法。