Alteration in protein interactions with proinsulin and insulin in type 2 diabetes

描述（由申请人提供）：2型糖尿病（T2D）是由β细胞无法产生足够的胰岛素以维持正常血糖引起的流行病。由于肥胖，胰岛素抵抗发展，迫使β细胞产生升高的胰岛素水平。虽然β细胞具有通过增加胰岛素产生来补偿的能力，但大多数具有胰岛素抵抗的个体发展为β细胞衰竭并失去β细胞质量。不幸的是，导致β细胞衰竭的机制尚不清楚。我们假设T2D中β细胞衰竭的根本原因是β细胞不能在内质网（ER）内折叠胰岛素原。为了测试β细胞衰竭的这一核心原因，我们召集了一个由研究人员组成的团队，使用最先进的蛋白质组学来确定导致β细胞死亡的分泌途径中的早期变化。为了实现这一目标，我们提出了三个具体目标（SA）。SA 1：开发灵敏的方法来定量β细胞中折叠与错误折叠胰岛素原的百分比。SA 2：建立定量确定分泌途径中与胰岛素原和胰岛素相互作用的整个蛋白质谱的程序。SA 3：设计细胞器分离和定量蛋白质组学，以绘制ER、高尔基体网络和β细胞分泌颗粒内的所有蛋白质。为了实现这些目标，我们将作为一个团队建立一个新的平台，以阐明β细胞分泌途径的蛋白质组学组织，以确定所有有助于胰岛素生物合成的因素。在未来，这种蛋白质组学方法将被应用于识别导致β细胞衰竭的早期预后标志物，并为评估T2D的新治疗方式提供基础。相关性（见说明）：2型糖尿病（T2D）是一种流行病，由于β细胞无法产生胰岛素。最近的研究结果支持这样的观点，即胰岛素原在内质网内的错误折叠可能是导致β细胞衰竭的初始事件。我们建议开发技术来识别促进胰岛素原折叠的蛋白质网络，这可能导致未来的T2D诊断和治疗。

DESCRIPTION (provided by applicant): Type 2 diabetes (T2D) is disease epidemic caused by a failure of beta cells to produce sufficient insulin to maintain euglycemia. As a consequence of obesity, insulin resistance develops that pressures the beta cell to produce elevated levels of insulin. Although beta cells have some capacity to compensate by increasing insulin production, a majority of individuals with insulin resistance develop beta cell failure and lose beta cell mass. Unfortunately the mechanism(s) leading to beta cell failure is not understood. We hypothesize that the fundamental cause of beta cell failure in T2D is an inability of the beta cell to fold pro-insulin within the endoplasmic reticulum (ER). To test this central cause of beta cell failure, we have brought together a team of established investigators to use state-of-the-art proteomics to identify the early changes within the secretory pathway that lead to beta cell demise. To accomplish this goal we propose three specific aims (SA). SA 1: To develop sensitive methods to quantify the percentage of folded versus misfolded pro-insulin in beta cells. SA 2: To establish procedures to quantitatively define the entire spectrum of proteins which interact with pro-insulin and insulin within the secretory pathway. SA 3: To devise organelle isolation and quantitative proteomics to map all the proteins within the ER, the Golgi network, and secretory granules of beta cells. To accomplish these aims we will function as a team to establish a novel platform to elucidate the proteomic organization of the beta cell secretory pathway to identify all the factors that contribute to insulin biogenesis. In the future, this proteomic approach will be applied to identify early prognostic markers that lead to beta cell failure and provide a foundation to evaluate new therapeutic modalities for T2D. RELEVANCE (See instructions): Type 2 diabetes (T2D) is an epidemic that results from an inability of beta cells to produce insulin. Recent findings support the notion that pro-insulin misfolding within the endoplasmic reticulum may be an initial event leading to beta cell failure. We propose to develop technologies to identify the protein network that promotes pro-insulin folding that may lead to future diagnostics and therapeutics for T2D.