Biophysical Studies of Amyloid Formation by Polypeptide Hormones

描述（由申请人提供）：淀粉样蛋白沉积发生在至少25种不同的人类疾病中。该项目的重点是淀粉样蛋白形成的胰岛淀粉样多肽（IAPP，淀粉不溶素），激素负责胰岛淀粉样蛋白在2型糖尿病。IAPP通常作为可溶性多肽与胰岛素一起分泌，但在2型糖尿病中通过未知机制聚集形成细胞外胰岛淀粉样蛋白。胰岛淀粉样蛋白或其形成过程对胰岛细胞有毒，并导致2型糖尿病的病理学。最近已经证明，由IAPP形成的淀粉样蛋白是胰岛细胞移植中的主要并发症因素。糖尿病在美国已达到流行病的程度，并正在成为发展中国家的主要健康威胁。关于IAPP形成淀粉样蛋白的机制或其形成过程中产生的有毒物质的性质，我们知之甚少。该研究将（I）确定IAPP形成淀粉样蛋白的机制;（II）检查IAPP突变的影响，该突变已被提出与早发性糖尿病有关;（III）定义淀粉样蛋白组装过程中最具毒性的物种并定义其构象特性;（IV）严格测试加速淀粉样蛋白形成减少IAPP诱导的细胞毒性的假设。这项研究将为治疗2型糖尿病和预防移植后胰岛移植失败提供深入的了解。这些经验教训也将有助于设计更可溶的IAPP变体来治疗1型糖尿病。实验生物物理学，生物化学和细胞生物学的跨学科组合将用于解决这些问题。正在开发的方法预计将广泛适用，并将有助于更好地控制其他疾病中淀粉样蛋白的形成。将实现五个具体目标。第一个涉及通过IAPP研究淀粉样蛋白形成的机制。第二个目标将研究增强淀粉样蛋白形成的基础上，由人类IAPP的天然突变体。第三个目标将使用高分辨率方法询问IAPP在淀粉样蛋白形成过程中聚集的有毒中间体的构象特性，而第四个目标将对有毒和无毒IAPP抑制剂复合物进行比较研究。最终的目标是测试一种预防IAPP毒性的新策略。

DESCRIPTION (provided by applicant): Amyloid deposition occurs in at least twenty five different human diseases. This project is focused on amyloid formation by Islet Amyloid Polypeptide (IAPP, Amylin), the hormone responsible for pancreatic islet amyloid in type 2 diabetes. IAPP is normally secreted as a soluble polypeptide together with insulin, but aggregates via an unknown mechanism in type 2 diabetes to form extracellular islet amyloid. Islet amyloid, or the process of its formation, is toxic to ¿-cells and contributes to the patholog of type 2 diabetes. Amyloid formation by IAPP has been recently shown to be a major complicating factor in islet cell transplantation. Diabetes has reached epidemic proportions in the United States and is emerging as a major health threat in the developing world. Relatively little is known about the mechanism of amyloid formation by IAPP or about the nature of the toxic species generated during its formation. The research will (I) determine the mechanism of amyloid formation by IAPP; (II) examine the effects of a mutation in IAPP which has been proposed to be linked to early onset diabetes; (III) define the most toxic species populated during amyloid assembly and define their conformational properties; (IV) critically test the hypotheses that accelerating amyloid formation reduces IAPP induced cytotoxicity. The research will provide insight into strategies for the treatment of type 2 diabetes and for the prevention of islet graft failure after transplantation. The lessons learned will also aid in the design of more soluble variants of IAPP to treat type 1 diabetes. An interdisciplinary combination of experimental biophysics, biochemistry and cell biology will be used to address these issues. The methods being developed are expected to be broadly applicable and will aid efforts to better control amyloid formation in other diseases. Five specific aims will be carried out. The first involves studies of the mechanism of amyloid formation by IAPP. The second aim will examine the basis for enhanced amyloid formation by a natural mutant of human IAPP. The third aim will interrogate the conformational properties of toxic intermediates populated during amyloid formation by IAPP using high resolution methods, while the fourth aim will conduct comparative studies of toxic and non-toxic IAPP inhibitor complexes. The final aim will test a new strategy for preventing IAPP toxicity.