PATHOGENESIS OF AL AMYLOIDOSIS

免疫球蛋白（AL）淀粉样变性的特征是细胞外 由单克隆免疫球蛋白轻链组成的纤维复合物的沉积 链（LC）。 这是系统性淀粉样变性最常见的形式， 任何系统性疾病的最坏预后。 中位寿命 组织活检证实的诊断是大约20个月。 虽然一些 对化疗的临床反应已在轶事病例中记录 对这种疾病没有特效疗法。 的总体目标 该建议旨在了解AL淀粉样变性的发病机制， 可以测试治疗策略。 有待检验的假设是， 单克隆免疫球蛋白轻链蛋白的结构 对于淀粉样蛋白的β-原纤维来说是原纤维形成过程中的关键因素。 这一假设的基础是有据可查的观察， 已经发现某些轻链蛋白质结构与 淀粉样纤维形成。 这些意见包括： 与κ淀粉样蛋白轻链蛋白相比， λ VI亚群蛋白质的深刻的淀粉样蛋白形成潜力， κ轻链内κ I淀粉样蛋白占优势 系列和体外研究显示， 免疫球蛋白轻链结构。 尽管这些发现是 都是基于蛋白质的一级结构，没有统一的假设， 被证实蛋白质结构参与淀粉样蛋白的发病机制。 的 本项目旨在调查第三和第四纪 淀粉样蛋白轻链蛋白的结构在淀粉样蛋白发病中的作用 原纤维形成。 为了实现这一目标， 免疫球蛋白轻链蛋白，其已被证明是 与淀粉样蛋白原纤维形成相关的蛋白质将由重组 技术. 然后这些重组蛋白将被结晶， 用X射线衍射法测定了它们的结构。 初步数据 已经证明了这种方法的可行性。 免疫球蛋白轻 链蛋白质已生产与此协议和晶体 一个这样的蛋白质的结构确定。 一旦有足够的结构 淀粉样蛋白轻链蛋白的测定，将它们与 与淀粉样蛋白无关的轻链蛋白结构 阵 分析应揭示那些结构性因素， 体内原纤维形成所必需的。 这些蛋白质也将作为 用于体外酶降解研究的底物。 这些研究和 体外原纤维形成潜力应该揭示更多关于 导致淀粉样纤维形成的蛋白质加工所必需的因子 阵 最终目标将是确定干扰的方法 从而改善或预防 这种情况。

Immunoglobulin (AL) amyloidosis is characterized by extracellular deposition of fibril complexes composed of monoclonal immunoglobulin light chains (LC). This is the most common form of systemic amyloidosis and has the worst prognosis of any of the systemic forms. Median life span after tissue biopsy proven diagnosis is approximately 20 months. While some clinical response to chemotherapy has been documented in anecdotal cases there is not specific therapy for this disease. The overall objective of this proposal is to understand the pathogenesis of AL amyloidosis so that therapeutic strategies can be tested. The hypothesis to be tested is that the structure of the monoclonal immunoglobulin light chain proteins which for beta-fibrils of amyloid is a key factor in the fibril forming process. The basis for this hypothesis is the well documented observation that only certain light chain protein structures have been found to be associated with amyloid fibril formation. These observations include the predominance of lambda compared to kappa amyloid light chain proteins, the profound amyloid forming potential of lambda VI subgroup proteins, predominance of kappa I amyloid proteins within the kappa light chain series, and in vitro studies showing fibril formation from specific immunoglobulin light chain structures. Despite these findings which are all based on primary protein structure, no unifying hypothesis has been proven for involvement of protein structure in amyloid pathogenesis. The present project is designed to investigate the tertiary and quaternary structure of amyloid light chain proteins in the pathogenesis of amyloid fibril formation. To achieve this goal the variable segments of immunoglobulin light chain proteins which have been proven to be associated with amyloid fibril formation will be produced by recombinant techniques. These recombinant proteins will then be crystallized and their structures determined by X-ray diffraction. Preliminary data have already proven the feasibility of this approach. Immunoglobulin light chain proteins have been produced with this protocol and the crystal structure of one such protein determined. Once sufficient structures of amyloid light chain proteins are determined, they will be compared to structures of light chain proteins which are not associated with amyloid formation. Analysis should reveal those structural factors which are necessary for fibril formation in vivo. These proteins will also serve as substrates for enzymatic degradation studies in vitro. These studies and in vitro fibril forming potential should reveal more information on factors necessary for protein processing which leads to amyloid fibril formation. The ultimate goal will be to identify methods of interfering with amyloid fibril formation and, therefore, amelioration or prevention of this condition.