Protein radicals in microglia: environmental mechanisms of chronic neurotoxicity

描述（由申请人提供）：帕金森病（PD）的病因目前尚不清楚，治疗无法阻止疾病进展。小胶质细胞是大脑的先天免疫细胞，与PD的进展有关，但驱动持续和病理激活的小胶质细胞的机制尚不清楚。环境因素与PD病因有关，可慢性激活小胶质细胞导致多巴胺能（DA）神经元损伤。小胶质细胞NADPH氧化酶和活性氧被认为是毒性小胶质细胞活化的关键因素，但它们如何调节小胶质细胞的功能在很大程度上是未知的。我们的首要假设是，环境损伤通过改变小胶质蛋白自由基生物化学导致慢性神经炎症和随后的进行性DA神经元损伤。因此，从NF: 2p50自由基开始，我们将测试特定的假设，即百草枯、LPS和MPTP/MPP+引起小胶质蛋白自由基，通过以下方式驱动进行性神经炎症和DA神经毒性：A)增强神经毒性促炎因子（小胶质启动）的产生；B)介导小胶质细胞解决促炎反应的失败。初步数据表明，小胶质细胞对促炎毒素（LPS）、直接神经毒物（MPTP/MPP+、反应性小胶质细胞增生）和双模毒物（百草枯）的反应是通过改变它们的蛋白自由基谱和增加细胞内NF:ss p50自由基的表达来实现的。因此，从NF:ss p50自由基开始，具体目的是：1)鉴定体外小胶质蛋白自由基（NF:ss p50自由基）的促炎和启动特性；2)表征NF: ssp50自由基在体内进行性DA神经元损伤中的作用；3)确定抑制NF:ss p50自由基形成的神经保护和抗炎作用。我们希望首次系统地证明NF:ss p50自由基是环境诱导的有害小胶质细胞激活的共同机制，从而促进进行性DA神经毒性。这些研究将为帕金森病的发病机制、ros信号以及环境诱导的氧化应激在神经退行性疾病中的作用的研究开辟新的途径。最后，这项工作将为能够减缓PD进展的新治疗靶点的识别和时机提供有价值的见解。

DESCRIPTION (provided by applicant): The etiology of Parkinson's disease (PD) is currently unknown and treatment is unable to halt disease progression. Microglias, the innate immune cells of the brain, are implicated in PD progression, but the mechanisms driving continuous and pathologically activated microglia are poorly understood. Environmental factors are associated with PD etiology and can chronically activate microglia to cause dopaminergic (DA) neuron damage. Microglial NADPH oxidase and reactive oxygen species have been strongly been implicated as key elements of toxic microglial activation, but how they regulate microglial function is largely unknown. Our overarching hypothesis is that environmental insult causes chronic neuroinflammation and consequent progressive DA neuron damage through changes in microglial protein radical biochemistry. Thus, beginning with the NF:2 p50 radical, we will test the specific hypothesis that paraquat, LPS, and MPTP/MPP+ cause microglial protein radicals that drive progressive neuroinflammation and DA neurotoxicity by: A) enhancing the production of neurotoxic pro- inflammatory factors (microglial priming); B) mediating the failure of microglia to resolve the pro- inflammatory response. Preliminary data indicate that microglia respond to pro-inflammatory toxins (LPS), direct neurotoxicants (MPTP/MPP+, reactive microgliosis), and dual-mode toxicants (paraquat) by changing their protein radical profile and increasing expression of the cytosolic NF:ss p50 radical. Thus, beginning with the NF:ss p50 radical, the specific aims are to: 1) identify the pro-inflammatory and priming characteristics of microglial protein radicals in vitro (NF:ss p50 radical); 2) characterize the role of the NF:ss p50 radical in progressive DA neuron damage in vivo; 3) determine the neuroprotective and anti-inflammatory effect of inhibiting NF:ss p50 radical formation. 1We expect to systematically demonstrate for the first time that the NF:ss p50 radical is a common mechanism of environmentally- induced deleterious microglial activation that fuels progressive DA neurotoxicity. These studies will define a new avenue of research in PD pathogenesis, ROS-signaling, and the role of environmentally-induced oxidative stress in neurodegenerative disease. Finally, this work will provide valuable insight into the identification and timing of novel therapeutic targets capable of slowing PD progression. PUBLIC HEALTH RELEVANCE These studies will define a new avenue of research in Parkinson's disease pathogenesis and the role of environmentally-induced oxidative stress in neurodegenerative disease. Finally, this work will provide valuable insight into the identification and timing of novel therapeutic targets capable of slowing Parkinson's disease progression.