Biophysical Studies of Amyloid Formation by Polypeptide Hormones

淀粉样蛋白的形成与三十多种不同的人类疾病有关。本申请描述 一个跨学科的计划，旨在确定淀粉样蛋白形成的机制，由人类胰岛淀粉样蛋白 多肽（IAPP，胰淀素），胰岛淀粉样变性的病原体诱导2型β细胞毒性 糖尿病IAPP通常作为可溶性多肽激素与胰岛素一起从胰腺分泌， β-细胞，并在葡萄糖代谢中起适应性作用。然而，IAPP在1型糖尿病中不存在， 在2型糖尿病中形成胰岛淀粉样蛋白。胰岛淀粉样蛋白形成的过程对β细胞是有毒的 并且在疾病进展中起重要作用。胰岛淀粉样蛋白的形成也是一个主要的复杂因素 在胰岛细胞移植和聚集的IAPP有助于下游心血管并发症 糖尿病糖尿病在美国已经达到流行病的程度，临床上没有 批准的胰岛淀粉样蛋白形成或毒性的抑制剂。IAPP在1型糖尿病和可溶性类似物中不存在 作为胰岛素治疗的替代物和潜在地用于治疗肥胖症是令人感兴趣的。一个 实验蛋白质生物物理学、生物化学和细胞生物学的跨学科组合将用于 阐明IAPP诱导淀粉样蛋白形成的机制。将实现三个具体目标。第一个目标 将阐明IAPP的N-末端区域在聚集中的作用。IAPP的N端区域是必需的 了解它在淀粉样蛋白形成中的作用对于开发一种 IAPP淀粉样蛋白形成的全貌以及用于开发可用作淀粉样蛋白的可溶性IAPP类似物 到胰岛素治疗。第二个目标将严格检查早期螺旋中间体在聚集中的作用， 这是药物设计的核心问题。第三个目标将描述最近发现的β片层 含有似乎在IAPP淀粉样蛋白形成中起关键作用的中间体， 导致β细胞死亡的实体这项工作将为2型糖尿病的治疗策略提供深入的见解。 糖尿病和预防移植后胰岛移植失败，并将有助于设计可溶性 IAPP的类似物这些研究将产生的一般原则和正在研究的方法， 该技术的开发将广泛适用于其他蛋白质聚集性疾病。

Amyloid formation has been implicated in more than thirty different human disorders. This application describes an interdisciplinary program designed to define the mechanism of amyloid formation by human islet amyloid polypeptide (IAPP, amylin), the causative agent of islet amyloidosis induced beta-cell toxicity in type-2 diabetes. IAPP is normally secreted as a soluble polypeptide hormone together with insulin from the pancreatic beta-cells and plays an adaptive role in glucose metabolism. However, IAPP is absent in type-1 diabetes, and forms pancreatic islet amyloid in type-2 diabetes. The process of islet amyloid formation is toxic to beta-cells and plays an important role in disease progression. Islet amyloid formation is also a major complicating factor in islet cell transplantation and aggregation of IAPP contributes to cardiovascular complications downstream of diabetes. Diabetes has reached epidemic proportions in the United States and there are no clinically approved inhibitors of islet amyloid formation or toxicity. IAPP is absent in type-1 diabetes and soluble analogs of human IAPP are of interest as adjuncts to insulin therapy and potentially for the treatment of obesity. An interdisciplinary combination of experimental protein biophysics, biochemistry, and cell biology will be used to elucidate the mechanism of amyloid formation by IAPP. Three specific aims will be carried out. The first aim will elucidate the role of the N-terminal region of IAPP in aggregation. The N-terminal region of IAPP is essential for the function of the hormone; understanding the role it plays in amyloid formation is critical for developing a full picture of IAPP amyloid formation and for developing soluble analogs of IAPP that can be used as adjuncts to insulin therapy. The second aim will critically examine the role early helical intermediates play in aggregation, an issue which is central to drug design. The third aim will characterize a recently discovered beta-sheet containing intermediate that appears to play a key role in IAPP amyloid formation and which may be the toxic entity responsible for beta-cell death. The work will offer insight into strategies for the treatment of type-2 diabetes and for the prevention of islet graft failure after transplantation and will aid efforts to design soluble analogs of IAPP. The general principles that will emerge from these studies and the methods which are being developed will be broadly applicable to other protein aggregation diseases.