Intracellular Amyloidogenesis and Apoptosis in NIDDM

NIDDM 中的细胞内淀粉样蛋白生成和细胞凋亡

• 批准号: 6702217
• 负责人: NORMAN L EBERHARDT
• 金额: $ 25.03万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-15 至 2007-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6702217
• 关键词: BCL2 gene /protein; amylin; amyloid proteins; amyloidosis; apoptosis; calcium binding protein; cysteine endopeptidases; electron microscopy; endoplasmic reticulum; gene expression; gene targeting; genetically modified animals; hormone regulation /control mechanism; insulin; laboratory mouse; light microscopy; noninsulin dependent diabetes mellitus; northern blottings; nuclear factor kappa beta; pancreatic islet function; pancreatic islets; pathologic process; protein structure function; terminal nick end labeling; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant) Non-insulin dependent diabetes (NIDDM) is an aging-related disease associated with arnyloid formation in the pancreas and loss of beta cell mass. The mechanism(s) of pancreatic beta cell death in NIDDM are unknown. NIDDM is a major disease that currently affects approximately 7.2 million Americans with annual costs exceeding $100 billion. A mutation (IAPPS20G) in he human wild-type islet amyloid precursor protein (hIAPPWT, amylin) has been associated with premature onset NIDDM in Japanese populations, providing a direct linkage of the IAPP gene with the genesis of NIDDM. IAPP is the major component of islet cell amyloid deposits which are a hallmark of NIDDM, suggesting that islet amyloid may be involved in the pathogenesis of this disease. We demonstrated that hIAPPWT expression in COS-1 and betaTC-3 cells results in the accumulation of intracellular amyloid within the endoplasmic reticulum (ER)/Golgi and induction of apoptosis. The expression of IAPPS2OG in these cells results in increased cytotoxicty and this is correlated with its increased in vitro amyloidogenic character as compared to IAPPWT. Accordingly, we have hypothesized that: (i) intracellular amyloidogenesis is a primary cause of beta cell death, and (ii) protective mechanisms that prevent intracellular amyloidogenesis are compromised by factors predisposing to NIDDM. Our preliminary data indicate that the accumulation of amyloid within he ER/Golgi is associated with an early induction of the molecular chaperone Bip/GRP78, a protein that appears to be signalling intermediate for two ER stress response pathways, unfolded protein response (UPR) and ER overload response (EOR), that are involved in ER quality control. Our data suggest that intracellular amyloid accumulation and subsequent induction of apoptosis may be mediated by one or both of these pathways. In the current studies we will: (1) assess the physiologic relevance of IAPPWT and IAPPS20G expression and amyloid formation and their relative ability to lead to diabetes in mouse knock-in models, (2) establish whether the UPR or EOR stress response is activated by intracellular amyloid accumulation and their role(s) in inducing apoptosis, (3) determine whether changes in ER Ca2+ activate apoptosis. (4) Determine the relative role of mitochondrial proteins in amyloid-induced apoptosis, and (5) define the distal caspase mediated pathways leading to apoptosis. These studies will increase our understanding of the contribution of intracellular amyloid accumulation, induction of apoptosis, and/or interference with ER trafficking to the pathogenesis of NIDDM.

描述（由申请人提供）非胰岛素依赖性糖尿病（NIDDM）为 与胰腺中砷形成相关的与衰老有关的疾病 β细胞量的损失。 NIDDM中胰腺β细胞死亡的机制 是未知的。 NIDDM是一种主要疾病，目前影响约7.2 每年成本超过1000亿美元的美国人。突变 （iApps20g）在人类野生型胰岛淀粉样蛋白蛋白（hiappwt， 氨基蛋白）与日本人群中的过早发作NIDDM有关， 提供IAPP基因与NIDDM的起源的直接联系。 Iapp是 胰岛细胞淀粉样蛋白沉积物的主要组成部分，它是 NIDDM，表明胰岛淀粉样蛋白可能与 这种疾病。我们证明了hiappwt在cos-1和betatc-3中的表达 细胞导致细胞内淀粉样蛋白在 内质网（ER）/高尔基体和凋亡的诱导。表达 这些细胞中的iApps2og导致细胞毒性增加，这是相关的 与IAPPWT相比，其体外淀粉样蛋白生成特征的增加。 因此，我们假设：（i）细胞内淀粉样生成是一种 β细胞死亡的主要原因以及（ii）防止的保护机制 细胞内淀粉样生成受到偏爱NIDDM的因素的损害。 我们的初步数据表明，淀粉样蛋白的积累 ER/Golgi与分子伴侣的早期诱导有关 BIP/GRP78，一种蛋白质，似乎是两个ER的信号传导中间 应力反应途径，展开的蛋白质反应（UPR）和ER超负荷 响应（EOR），与ER质量控制有关。我们的数据表明 细胞内淀粉样蛋白的积累和随后的凋亡诱导可能是 由这一途径之一介导。在当前的研究中，我们将：（1） 评估IAPPWT和IAPPS20G表达和淀粉样蛋白的生理相关性 形成及其相对能够导致糖尿病的相对能力 模型，（2）确定UPR或EOR应力响应是否被激活 细胞内淀粉样蛋白的积累及其在诱导凋亡中的作用，（3） 确定ER Ca2+的变化是否激活凋亡。 （4）确定 线粒体蛋白在淀粉样蛋白诱导的凋亡中的相对作用，（5） 定义导致凋亡的远端caspase介导的途径。这些研究 将增加我们对细胞内淀粉样蛋白的贡献的理解 积累，诱导凋亡和/或干扰ER运输 NIDDM的发病机理。