Understanding PDI-related neurotoxicity and advancing preventative approaches

 描述（由申请方提供）：蛋白质二硫键异构酶（PDI）是一种内质网（ER）驻留的氧化还原酶伴侣，可催化含二硫键蛋白质的成熟。S-亚硝基化PDI（SNO-PDI）是其催化半胱氨酸响应于亚硝化应激的化学修饰，已在帕金森氏症和阿尔茨海默氏症患者的死后大脑中沿着突触亲蛋白-1：α-突触核蛋白蛋白聚集体（称为路易体）一起发现。细胞中的其他研究表明，SNO-PDI形成的水平与次要但关键的帕金森病生物标志物synphilin-1以NO敏感的方式的聚集和积累直接相关。虽然SNO-PDI形成导致聚泛素化蛋白的积累，但天然PDI（非SNO-PDI）的表达减弱了帕金森病细胞模型中的这些作用。这些数据表明，PDI是神经保护性的，并强调需要功能性保护PDI的催化活性，作为亚硝化应激相关帕金森病发病机制的关键预防方法。这些数据还表明PDI功能障碍参与神经病如阿尔茨海默氏症的路易体变体（LBVAD）和阿尔茨海默氏症的发病机制。 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然存在差距。我们假设SNO-PDI的形成可能引起α-突触核蛋白的聚集，α-突触核蛋白是主要的帕金森病和LBVAD生物标志物蛋白和路易体成分。作为我们假设的一个推论，有可能设计用于 防止SNO-PDI形成对帕金森病具有神经保护和预防作用。将通过在细胞系模型中检查作为亚硝化损伤的函数的α-突触核蛋白的聚集来检验该假设。此外，鞣花酸、β-羟基丁酸钠和铁抑素-1类似物的翻译可行性，我们的实验室已初步证明其具有神经保护作用，将在鱼藤酮大鼠帕金森模型中进行测定。该项目的总体目标是为长期工作奠定基础，这些工作涉及开发通过减轻氧化和亚硝化应激的影响而具有神经保护作用的神经相关小分子疗法。

 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.