Understanding PDI-related neurotoxicity and advancing preventative approaches

 描述(申请人提供)：蛋白质二硫键异构酶(PDI)是内质网(ER)驻留的氧化还原酶伴侣，催化含有二硫键的蛋白质的成熟。在帕金森氏症和阿尔茨海默病患者的尸检脑中，发现了一种由其催化的半胱氨酸对亚硝化应激做出的化学修饰--S-亚硝酸盐PDI(SNO-PDI)，以及SynPhilin-1：α-突触核蛋白聚集体(称为路易体)。在细胞中的进一步研究表明，SNO-PDI的形成水平与帕金森病次要但关键的生物标记物SynPhilin-1以不敏感的方式聚集和积累直接相关。虽然SNO-PDI的形成导致多泛素化蛋白的积累，但在帕金森细胞模型中，天然PDI(非SNO-PDI)的表达减弱了这些影响。这些数据表明，PDI具有神经保护作用，并强调有必要保留PDI的催化活性，以此作为亚硝酸盐应激相关帕金森病发病的关键预防方法。这些数据还表明，PDI功能障碍参与了阿尔茨海默氏路易体变异型(LBVAD)和阿尔茨海默氏症等神经疾病的发病机制。然而，在旨在确定其他神经毒性相关生物标志物是否作为SNO-PDI形成的函数积累的研究中仍存在空白。我们推测，SNO-PDI的形成可能会引起α-突触核蛋白的聚集，α-突触核蛋白是帕金森病和LBVAD的主要生物标志物蛋白和路易体成分。作为我们假设的推论，有可能旨在 防止SNO-PDI的形成对帕金森氏症具有神经保护和预防作用。这一假说将通过在细胞系模型中检验α-突触核蛋白的聚集作为亚硝化性侮辱的函数来检验。此外，我们的实验室已经初步证明具有神经保护作用的鞣花酸、β-羟基丁酸钠和铁抑素-1类似物的翻译可行性将在鱼藤酮大鼠帕金森模型中进行测试。该项目的总体目标是为长期工作奠定基础，这些工作涉及开发药理上相关的小分子疗法，这些疗法通过减轻氧化和亚硝化应激的影响来保护神经。

 DESCRIPTION (provided by applicant): Protein disulfide isomerase (PDI) is an endoplasmic reticulum (ER)-resident oxidoreductase chaperone that catalyzes the maturation of disulfide-bond-containing proteins. S-nitrosylated PDI (SNO-PDI), which is the chemical modification of its catalytic cysteine in response to nitrosative stress, has been found in post-mortem brains of Parkinson's and Alzheimer's disease victims along with synphilin-1:alpha-synuclein protein aggregates (called Lewy Bodies). Additional studies in cells revealed that levels of SNO-PDI formation directly co-related with the aggregation and accumulation of the minor but critical Parkinsonian biomarker synphilin-1 in a NO-sensitive manner. While SNO-PDI formation leads to the accumulation of polyubiquitinated proteins, expression of native PDI (non-SNO-PDI) attenuates these effects in a Parkinsonian cell model. These data show that PDI is neuroprotective and underscore the need for functional preservation of PDI's catalytic activity as a key preventative approach to pathogenesis of nitrosative-stress-related Parkinson's. The data also suggest the involvement of PDI dysfunction in the pathogenesis of neuropathies such as the Lewy Body Variant of Alzheimer's (LBVAD) and Alzheimer's. However, there is still a gap in studies designed to determine whether other neurotoxicity-related biomarkers accumulate as a function of SNO-PDI formation. We hypothesize that SNO-PDI formation may provoke aggregation of alpha-synuclein, the major Parkinsonian and LBVAD biomarker protein and Lewy-body constituent. As a corollary to our hypothesis, it is possible that strategies designed to prevent SNO-PDI formation are neuroprotective and prophylactic to Parkinson's. The hypothesis will be tested by examining the aggregation of alpha-synuclein as a function of nitrosative insult in a cell line model. Furthermore, the translational feasibility of ellagic acid, Na-betahydroxybutyrate and Ferrostatin-1 analogs, which our lab has preliminarily demonstrated as being neuroprotective, will be assayed in a rotenone rat Parkinson model. The overall objective of this project it to lay the foundation for long-term work involving the development of pharmacologically relevant small molecule therapies that are neuroprotective by mitigating the effects of oxidative and nitrosative stress.