BIOCHEMICAL MECHANISM OF BETA-CELL DESTRUCTION

描述(改编自申请人的摘要)：这项研究建议于 这份修订后的意见书仍然有一个广泛的目标，即澄清 与胰岛β细胞破坏相关的细胞机制 自身免疫性糖尿病。与绩效相关的重要观察 这项研究的中心是IL-1的典型作用 胰岛β细胞功能。IL-1抑制胰岛素分泌及其靶点 线粒体酶的铁硫中心。一氧化氮是一种效应器分子 由IL-1诱导β细胞表达iNOS产生。Inf伽马降低 胰岛诱导型一氧化氮合酶表达所需的IL-1浓度 并与iNOS mRNA的稳定性增加有关。在缺席时 IL-1干扰素-γ对β细胞功能无调节作用。 具体目标1将阐明所需的细胞信号机制 IL-1诱导β细胞诱导型一氧化氮合酶表达及其机制的研究 其中干扰素-γ启动并增强IL-1诱导的iNOS表达。 这一目的是基于P.I.的观察，即IL-1选择性地 β细胞刺激诱导型一氧化氮合酶(INOS)表达 IL-1诱导的iNOS表达可通过干扰素-γ来启动和增强。 因此，细胞因子诱导了iNOS的表达，从而产生了 高水平的NO是β细胞破坏的一种机制。 特异性目标2将确定IL-1的细胞来源，其亚型 IL-1、控制胰岛内IL-1释放的机制及其作用 胰岛内释放对β细胞功能的影响。这一目标旨在 检验胰岛内巨噬细胞激活介导 导致胰岛β细胞破坏的初始事件。 特殊目标3将确定iNOS和COX-2(COX)的细胞来源 催化生物合成途径中的第一反应，负责 前列腺素的生产。COX-2是可诱导的，IL-1诱导它和iNOS 刺激其活性)，NO是否激活COX-2，以及COX-2和 INOS参与胰岛炎症和胰岛β细胞损伤。一个主要目标 其目的是检验促炎症和破坏性的假设 NO直接参与胰岛炎症和B细胞损伤 在自身免疫性糖尿病的NOD小鼠模型中。

DESCRIPTION (Adapted from applicant's abstract): This research proposed in this revised submission continues to have the broad goal to elucidate the cellular mechanisms associated with pancreatic islet beta cell destruction in autoimmune diabetes. Important observations relevant to the performance of this research are centered around the well characterized effects of IL-1 on islet beta cell function. IL-1 inhibits insulin secretion and targets iron-sulfur centers of mitochondrial enzymes. NO is an effector molecule produced by IL-1 induced iNOS expression by beta cells. INF gamma reduces the concentration of IL-1 required to stimulate iNOS expression by islets and is associated with an increased stability of iNOS mRNA. In the absence of IL-1 IFN gamma does not modulate beta cell function. Specific aim 1 will elucidate the cellular signaling mechanisms required for IL-1 induced iNOS expression by beta cells and determine the mechanism by which IFN gamma primes for and potentiates IL-1 induced iNOS expression. This aim is based on the observations by the P.I. that IL-1 selectively stimulates inducible nitric oxide synthase (iNOS) expression by beta cells and that IFNgamma primes for and potentiates IL-1 induced iNOS expression. Therefore, cytokine induced iNOS expression and consequent production of high levels of NO is one mechanism of beta cell destruction. Specific aim 2 will determine the cellular source of IL-1, the isoforms of IL-1, the mechanisms controlling intra-islet release of IL-1 and the effects of intra-islet release on beta cell function. This aim is directed to testing the hypothesis that intra-islet macrophage activation mediates the initial events leading to islet beta cell destruction. Specific aim 3 will determine the cellular sources of iNOS and COX-2 (COX catalyzes the first reaction in the biosynthetic pathway responsible for the production of prostaglandins. COX 2 is inducible, IL-1 induces it and iNOS stimulates its activity), whether NO activates COX-2 and whether COX-2 and iNOS participate in islet inflammation and beta cell damage. A major goal of this aim is to test the hypothesis that proinflammatory and destructive actions of NO directly participate in islet inflammation and B cell damage in the NOD mouse model of autoimmune diabetes.