Biophysical Studies of Amyloid Formation by Polypeptide Hormones

淀粉样蛋白沉积发生在二十多种不同的人类疾病中。本项目涉及胰岛淀粉样多肽（IAPP）的淀粉样蛋白形成，IAPP是2型糖尿病中负责胰岛淀粉样蛋白的内分泌激素。胰岛淀粉样蛋白在2型糖尿病的发病中起重要作用，也是胰岛细胞移植中的一个主要问题。尽管IAPP具有明显的重要性，但对它的淀粉样蛋白形成知之甚少，而且胰岛淀粉样蛋白形成的机制也不清楚。本文概述的研究将：（1）确定IAPP形成淀粉样蛋白的机制;（2）推断proIAPP加工中间体在淀粉样蛋白形成中的作用，这是去年出现的一个关键问题;（3）开发IAPP和proIAPP形成淀粉样蛋白的抑制剂;（4）测试改善现有淀粉样蛋白形成抑制剂的一般策略。这些经验教训将为2型糖尿病的治疗和预防策略提供深入了解，并有望帮助更好地控制其他疾病中病理性淀粉样蛋白的形成。实验生物物理学，细胞生物学和分子动力学模拟的跨学科组合将被用来解决这些问题。将实现三个具体目标。第一部分涉及IAPP形成淀粉样蛋白的机制的研究，由四个协同子目标组成：A）调节单体IAPP的构象集合对原纤维形成动力学的影响将被确定; B）螺旋中间体在IAPP形成淀粉样蛋白中起关键作用的假设将被检验; C）在IAPP原纤维形成期间发生的二级结构的变化将用残基特异性分辨率来定义; D）将定义单个侧链在IAPP形成淀粉样蛋白中的作用。第二个目标是确定前IAPP加工中间体在淀粉样蛋白形成中的作用。第三个目标是通过IAPP开发新的淀粉样蛋白形成抑制剂，并测试它们抑制细胞死亡的能力。改进现有抑制剂的一般方法将作为aim-3的一部分进行测试。

Amyloid deposition occurs in more than twenty different human diseases. This project is concerned with amyloid formation by Islet Amyloid Polypeptide (IAPP), the endocrine hormone responsible for pancreatic islet amyloid in type 2 diabetes. Islet amyloid significantly contributes to the pathology of type 2 diabetes and is also a major problem in islet cell transplantation. Comparatively little is known about amyloid formation by IAPP despite its obvious importance and the mechanism underlying islet amyloid formation is not understood. The studies outlined here will; (1) determine the mechanism of amyloid formation by IAPP; (2) deduce the role of proIAPP processing intermediates in amyloid formation, a topic which has emerged as a critical issue in the last year (3) develop inhibitors of amyloid formation by IAPP and proIAPP and (4) test a general strategy for improving existing inhibitors of amyloid formation. The lessons learned will provide insight into strategies for the treatment and prevention of type 2 diabetes, and are expected to aid efforts to better control pathological amyloid formation in other diseases. An interdisciplinary combination of experimental biophysics, cell biology, and molecular dynamics simulations will be used to address these issues. Three specific aims will be carried out. The first involves studies of the mechanism of amyloid formation by IAPP and is made up of four synergistic sub aims: A) The effects of modulating the conformational ensemble of monomeric IAPP on the kinetics of fibril formation will be determined; B) The hypothesis that a helical intermediate plays a critical role in amyloid formation by IAPP will be tested; C) The changes in secondary structure that occur during IAPP fibril formation will be defined with residue specific resolution; D) The role individual side chains play in amyloid formation by IAPP will be defined. The second aim will define the role of pro-IAPP processing intermediates in amyloid formation. The third aim will lead to the development of new inhibitors of amyloid formation by IAPP and test their ability to inhibit cell death. A general methodology for improving existing inhibitors will be tested as part of aim-3.