TRANSGENIC MOUSE MODEL FOR FAMILIAL HYPERINSULINISM

家族性高胰岛素血症转基因小鼠模型

• 批准号: 6358711
• 负责人: Joseph Bryan
• 金额: $ 5.23万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-30 至 2002-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6358711
• 关键词: B lymphocyte; calcium channel; diabetes mellitus genetics; disease /disorder model; drug receptors; electrophysiology; gene mutation; gene targeting; genetic disorder; genetically modified animals; glucagon; glucose metabolism; hyperinsulinism; hypoglycemia; insulin; laboratory mouse; membrane potentials; neurons; noninsulin dependent diabetes mellitus; pancreatic islet function; pancreatic islets; potassium channel; somatostatin; sulfonylurea; tissue /cell culture

The objective of this proposal is to understand how beta-cells couple metabolism to membrane activity using SUR1 null mice. We have reconstituted the beta-cell ATP-sensitive K+ channel, KATP, from the high affinity sulfonylurea receptor (SUR1) and a silent member of the small inward rectifier family (KIR6.2). KATP is the target for the sulfonylureas used to treat non-insulin dependent diabetes mellitus, NIDDM, and for K+ channel openers (KCOs) used to treat hyperinsulinism. SUR1 is a member of the ATP-binding cassette superfamily with multiple transmembrane domains and two nucleotide binding folds (NBFs). KATP channels play a key role in regulating insulin secretion. Glucose metabolism alters the ATP/ADP ratio in beta-cells, particularly MgADP levels that stimulate openings of KATP, which set the beta-cell resting membrane potential. SUR1 senses changes in nucleotide levels and reduces K+ flux through KATP thus depolarizing the beta-cell membrane. Depolarization activates voltage-gated Ca2+ channels; the resulting Ca2+ transients trigger insulin exocytosis. Mutations in SUR1 that inactivate KATP, or affect its regulation by MgADP, cause persistent hyperinsulinemic hypoglycemia of infancy (PHHI), an autosomal recessive disease of newborns characterized by high insulin levels despite severe hypoglycemia. We have made SUR1 null mice in order to characterize the PHHI phenotype and study the functions of KATP channels in insulin secretion. We propose to characterize these animals, specifically, the levels of glucose, insulin, glucagon and somatostatin will be assayed to determine if homozygotic SUR1 null mice are hyperinsulinemic and hypoglycemic and to characterize heterozygotic animals. Pancreatic islets will be cultured and used for electrophysiological characterization of KATP. These mice will provide research material for the study of the most common cause of persistent hypoglycemia in newborns, and will provide insight into the physiology and pathology of insulin secretion. We will correct the pancreatic defect by expressing SUR1 cDNA in the pancreas under control of the rat insulin II promoter. The resulting animals will be used to study extra-pancreatic functions of the SUR/KIR6.2 ATP-sensitive potassium channels, particularly in neurons.

这项提议的目的是了解β细胞是如何结合的 利用SUR1缺失小鼠代谢到细胞膜活性。我们有 重组β细胞ATP敏感性K+通道KATP 高亲和力磺脲受体(SUR1)和沉默的成员 小型内向整流器系列(KIR6.2)。KATP是 磺脲类药物用于治疗非胰岛素依赖型糖尿病， NIDDM，以及用于治疗高胰岛素血症的K+通道开放剂(KCO)。 SUR1是ATP结合盒超家族的成员，具有多个 跨膜区和两个核苷酸结合折叠(NBF)。KATP 通道在调节胰岛素分泌方面起着关键作用。葡萄糖 代谢改变β细胞中的ATP/ADP比率，尤其是镁ADP 刺激KATP开放的水平，从而使β细胞处于休息状态 膜电位。SUR1感知核苷酸水平的变化并降低 K+流经KATP，从而使β细胞膜去极化。 去极化激活电压门控钙离子通道；由此产生的钙离子 瞬间会触发胰岛素的胞吐作用。SUR1基因突变 使KATP失活，或影响其由镁ADP调节，导致持久 常染色体隐性遗传性婴儿期高胰岛素血症 新生儿的疾病，以高胰岛素水平为特征，尽管严重 低血糖症。我们已经制作了SUR1缺失的小鼠，以表征 胰岛素中KATP通道的PHHI表型及功能研究 分泌物。我们建议将这些动物的特征，特别是 测定血糖、胰岛素、胰高血糖素和生长抑素水平 为了确定纯合子SUR1缺失小鼠是否存在高胰岛素血症和 降血糖和确定杂合子动物的特征。胰腺 胰岛将被培养并用于电生理 KATP的表征。这些小鼠将为以下研究提供材料 持续性低血糖最常见原因的研究 新生儿，并将提供对生理学和病理学的洞察 胰岛素分泌。我们将通过表达来纠正胰腺缺陷 大鼠胰岛素II启动子调控下胰腺中的SUR1基因。 由此产生的动物将被用于研究胰腺外功能。 SUR/KIR6.2对ATP敏感的钾通道，尤其在 神经元。