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。该项目涉及胰岛淀粉样蛋白多肽（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。胰岛淀粉样蛋白对2型糖尿病的病理有重要影响，也是胰岛细胞移植的一个主要问题。尽管IAPP具有明显的重要性，但对其淀粉样蛋白形成的了解相对较少，而且胰岛淀粉样蛋白形成的机制尚不清楚。这里概述的研究将；(1)通过IAPP确定淀粉样蛋白的形成机制；(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)通过IAPP和proIAPP开发淀粉样蛋白形成抑制剂；(4)测试改进现有淀粉样蛋白形成抑制剂的一般策略。从中吸取的经验教训将为2型糖尿病的治疗和预防策略提供见解，并有望帮助更好地控制其他疾病的病理性淀粉样蛋白形成。实验生物物理学、细胞生物学和分子动力学模拟的跨学科结合将用于解决这些问题。将实现三个具体目标。第一个涉及IAPP淀粉样蛋白形成机制的研究，由四个协同子目标组成：A)将确定调节单体IAPP的构象集合对纤维形成动力学的影响；B)将验证螺旋中间体在IAPP淀粉样蛋白形成中起关键作用的假设；C) IAPP原纤维形成过程中二级结构的变化将用残基比分辨率来定义；D)将定义IAPP中单个侧链在淀粉样蛋白形成中的作用。第二个目标将确定亲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目标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.