Insulin Secretion in Hyperinsulinism Human Islets

高胰岛素血症人类胰岛的胰岛素分泌

• 批准号: 10348708
• 负责人: Diva D. De Leon
• 金额: $ 63.25万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-15 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10348708
• 关键词: Address; Affect; Beckwith-Wiedemann Syndrome; Beta Cell; Calcium; Child; Chronic; Complex; Defect; Disease; Electrophysiology (science); Failure; Functional disorder; Funding; Gene Expression; Genetic; Genetic Diseases; Genomics; Health; Human; Human Genetics; Hyperinsulinism; Infant; Insulin; Ion Channel; Knock-in; Knock-out; Long QT Syndrome; Membrane Potentials; Metabolism; Modeling; Molecular; Mus; Mutation; Neurodevelopmental Impairment; Non-Insulin-Dependent Diabetes Mellitus; Outcome Study; Pancreas; Pathway interactions; Persistent Hyperinsulinemia Hypoglycemia of Infancy; Pharmacology; Phenotype; Physiological; Play; Potassium Channel; Rest; Risk; Role; Secondary to; Stimulus; Testing; Up-Regulation; Variant; Withdrawal; basal insulin; blood glucose regulation; differential expression; genetic approach; genetic manipulation; improved; in vivo; insulin regulation; insulin secretion; interest; islet; metabolomics; mouse model; new therapeutic target; novel; response

PROJECT SUMMARY The study of human islets isolated from the pancreas of infants with congenital hyperinsulinism (HI) during the previous funding cycle has afforded us the unique opportunity to examine the islet phenotype in KATPHI integrating function, metabolomics, and genomics. Our findings revealed a complex pathophysiology in which the primary KATP channel defect leads to secondary consequences affecting gene expression, fuel metabolism, and both the triggering and amplifying pathways of insulin secretion. However, many critical questions for addressing unmet needs for the treatment of HI and for the understanding of normal physiological mechanisms of insulin secretion remain unanswered. We are particularly interested in examining the role of two ion channels that are differentially expressed in HI islets in the normal regulation of insulin secretion and their potential role in the pathophysiology of HI: TMEM16A, a Ca2+-activated Cl– channel encoded by ANO1 which is markedly upregulated in KATPHI islets, and Kv7.1, encoded by KCNQ1, whose expression is markedly decreased in islets isolated from the pancreases of children with Beckwith Wiedemann syndrome and HI. In preliminary studies we found that pharmacological modulation of these channels alters insulin secretion. Our overall hypothesis is that both Kv7.1 and TMEM16A play critical roles in the termination of insulin secretion by keeping β-cell Vm hyperpolarized at rest and facilitating β-cell Vm repolarization after stimulation. To test this hypothesis, we propose two aims to examine the role of Kv7.1 and TMEM16A in the regulation of insulin secretion in normal and HI islets. To accomplish these aims we will use genetic and pharmacological approaches to modulate the activity of these channels in normal and HI human and mouse islets. We will examine: 1) the contribution of TMEM16A and Kv7.1 to β-cell Vm at resting and stimulated states; 2) the effect of TMEM16A and Kv7.1 activation and inhibition on cytosolic calcium and insulin secretion in normal human and mouse islets; 3) the effect of genetic inactivation of TMEM16A and Kv7.1 on glucose homeostasis in vivo and fuel-stimulated insulin secretion in vivo and in isolated islets using genetically modified mouse models. This study will expand our understanding of the pathophysiology of HI and will facilitate the identification of new genetic causes and potential new therapeutic targets for this devastating disease. The study may also have implications for the understanding of the mechanisms implicated in the progressive β-cell failure that leads to type 2 diabetes.

项目概要 从先天性高胰岛素血症 (HI) 婴儿胰腺中分离的人类胰岛的研究 之前的资助周期为我们提供了独特的机会来检查 KATPHI 中的胰岛表型 我们的研究结果揭示了复杂的病理生理学，其中包括功能、代谢组学和基因组学。 主要的 KATP 通道缺陷会导致影响基因表达、燃料代谢、 然而，胰岛素分泌的触发和放大途径仍存在许多关键问题。 解决 HI 治疗和理解正常生理机制方面未满足的需求 我们对研究两种离子的作用特别感兴趣。 HI胰岛中差异表达的通道在胰岛素分泌的正常调节中及其作用 HI 病理生理学中的潜在作用：TMEM16A，一种由 ANO1 编码的 Ca2+ 激活的 Cl- 通道， KATPHI 胰岛和 Kv7.1（由 KCNQ1 编码）中显着上调，其表达显着上调 从患有 Beckwith Wiedemann 综合征和 HI 的儿童的胰腺中分离出的胰岛减少。 初步研究我们发现这些通道的药理调节会改变我们的胰岛素分泌。 总体假设是 Kv7.1 和 TMEM16A 在胰岛素终止中发挥关键作用 通过在静息时保持 β 细胞 Vm 超极化并在静息后促进 β 细胞 Vm 复极化来分泌 为了检验这一假设，我们提出了两个目标来检验 Kv7.1 和 TMEM16A 在 正常和 HI 胰岛中胰岛素分泌的调节为了实现这些目标，我们将使用遗传和 在正常和HI人类和小鼠中调节这些通道活性的药理学方法 我们将检查：1) TMEM16A 和 Kv7.1 对静息和刺激时 β 细胞 Vm 的贡献。 指出；2) TMEM16A 和 Kv7.1 激活和抑制对细胞质钙和胰岛素分泌的影响 在正常人和小鼠胰岛中；3) TMEM16A 和 Kv7.1 基因失活对葡萄糖的影响 使用转基因技术实现体内稳态，并在体内和分离的胰岛中刺激胰岛素分泌 这项研究将扩大我们对 HI 病理生理学的理解，并促进 确定这种毁灭性疾病的新遗传原因和潜在的新治疗靶点。 研究还可能对理解进行性 β 细胞相关机制有影响 导致 2 型糖尿病的失败。