MOLECULAR MECHANISMS OF BETA CELL DYFUNCTION IN DIABETES

本计划项目申请的重点是分子 与胰岛素分泌相关的机制。特别强调的是 在确定与分子缺陷相关的 慢性阻塞性肺疾病患者β细胞功能异常的认识和治疗 早期IDDM。该方案由4个项目和2个核心组成，将进行 对胰岛素分泌过程的多学科研究 包括基因的基本分子生物学在内的许多观点 他们的产品在胰岛素分泌中起着重要作用，为了研究 正常和糖尿病动物中β细胞基因表达的调节， 与β细胞分泌功能障碍的电生理学相关性 小分子GTP结合蛋白在脑缺血再灌注损伤中作用的研究 胰岛素分泌的调节。项目1旨在克隆和表征 在β细胞中表达的参与调节的基因 胰岛素分泌对细胞内钙离子浓度的影响 K+包括β细胞钙通道、电压和ATP敏感性K+ 通道和IP3受体。项目2旨在研究分子 胰岛素分泌生理及其在糖尿病中的病理生理学 调查引起正常振荡模式的因素 胰岛素分泌。胰岛β细胞基因表达的调控 将在正常和糖尿病的比率以及在β细胞 大剂量葡萄糖输注可引起机体功能障碍。这个 胰岛素分泌的药理控制将在一个模型中进行研究 BetaTC3细胞系，已经证明 在低浓度孵育后，提高其对葡萄糖的胰岛素反应性 当与高糖相比时，葡萄糖。项目3旨在研究 糖尿病患者胰岛β细胞功能降低的电生理学相关性 通过研究正常和糖尿病或糖尿病前期动物的β细胞 用全细胞和单通道膜片钳技术和Fura-2 用数字成像荧光法研究钙、钾离子的形态 发信号。项目4旨在定义小GTP结合的作用 引导细胞内交通的蛋白质(包括Rab 1、2、6和3) 被包装在贝塔颗粒中的蛋白质。这将是 通过研究这些蛋白质在细胞内的定位来完成 以及它们的过度生产和功能改变对胰岛素原的影响 β细胞系的生物合成、加工和分泌。《野兽》 细胞培养核心公司将为研究人员提供完整的动物模型 糖尿病和β细胞功能障碍，孤立的胰岛和分散的β细胞 细胞、模型β细胞系和异源系统表达 克隆基因。

The focus of this Program Project Application is on the molecular mechanisms associated with insulin secretion. Particular emphasis will be upon the identification of the molecular defects relevant to the understanding and treatment of abnormal beta cell function in patients with early IDDM. The Program consists of 4 projects and 2 cores and will carry out a multidisciplinary investigation of the insulin secretory process from a number of standpoints including the basic molecular biology of genes whose products play an important role in insulin secretion, to the study of the regulation of beta cell gene expression in normal and diabetic animals, to the electrophysiologic correlates of beta cell secretory dysfunction and an investigation of the role of the small GTP-binding proteins in the regulation of insulin secretion. Project 1 aims to clone and characterize genes expressed in the beta cell which are involved in the regulation of insulin secretion through effects on intracellular concentrations of Ca2+ and K+ including beta cell calcium channels, voltage and ATP-sensitive K+ channels and the IP3 receptors. Project 2 aims to study the molecular physiology of insulin secretion and its pathophysiology in diabetes by investigating factors responsible for the normal oscillatory pattern of insulin secretion. The regulation of pancreatic beta cell gene expression will be studied in normal and diabetic rates and in rats in which beta cell dysfunction has been induced by high dose glucose infusion. The pharmacologic control of insulin secretion will be investigated in a model beta cell line, the betaTC3 cell line which has been demonstrated to increase its insulin responsiveness to glucose, after incubation in low glucose when compared to high glucose. Project 3 aims to study the electrophysiologic correlates of the reduced beta cell function in diabetes by investigating beta cells from normal and diabetic or prediabetic animals with the whole cell and single channel patch clamp techniques and fura-2 fluorimetry with digital imaging to study patterns of Ca2+ and K+ signalling. Project 4 aims to define the role of small GTP-binding proteins (including Rab 1,2,6 and 3) in directing the intracellular traffic of proteins destined for packaging in beta granules. This will be accomplished by studying the intracellular localization of these proteins and the effects of their overproduction and altered function on proinsulin biosynthesis, processing and secretion from beta cell lines. The Animal and Cell Culture Core will provide investigators with whole animal models of diabetes and beta cell dysfunction, isolated islets and dispersed beta cells, model beta cell lines and heterologous systems for expression of cloned genes.