The NLRP3 inflammasome signaling pathway is a major contributor to the neuroinflammatory process in the central nervous system. Oxidative stress and mitochondrial dysfunction are key pathophysiological processes of many chronic neurodegenerative diseases, including Parkinson's disease (PD). However, the inter-relationship between mitochondrial defects and neuroinflammation is not well understood. In the present study, we show that impaired mitochondrial function can augment the NLRP3 inflammasome-driven proinflammatory cascade in microglia. Primary mouse microglia treated with the common inflammogen LPS increased NLRP3 and pro-IL-1β expression. Interestingly, exposure of LPS-primed microglial cells to the mitochondrial complex-I inhibitory pesticides rotenone and tebufenpyrad specifically potentiated the NLRP3 induction, ASC speck formation and pro-IL-1β processing to IL-1β in a dose-dependent manner, indicating that mitochondrial impairment heightened the NLRP3 inflammasome-mediated proinflammatory response in microglia. The neurotoxic pesticide-induced NLRP3 inflammasome activation was accompanied by bioenergetic defects and lysosomal dysfunction in microglia. Furthermore, the pesticides enhanced mitochondrial ROS generation in primary microglia, while amelioration of mitochondria-derived ROS by the mitochondria-targeted antioxidant mito-apocynin completely abolished IL-1β release, indicating mitochondrial ROS drives potentiation of the NLRP3 inflammasome in microglia. Exposure to conditioned media obtained from mitochondrial inhibitor-treated, LPS-primed microglial cells, but not unprimed cells, induced dopaminergic neurodegeneration in cultured primary mesencephalic and human dopaminergic neuronal cells (LUHMES). Notably, our in vivo results with chronic rotenone rodent models of PD further support the activation of proinflammatory NLRP3 inflammasome signaling due to mitochondrial dysfunction. Collectively, our results demonstrate that mitochondrial impairment in microglia can amplify NLRP3 inflammasome signaling, which augments the dopaminergic neurodegenerative process.

中文翻译：

---

小胶质细胞的线粒体损伤在帕金森氏病的细胞培养和动物模型中放大了NLRP3炎性体促炎信号。

NLRP3炎性体信号通路是中枢神经系统神经炎过程的主要贡献者。氧化应激和线粒体功能障碍是许多慢性神经退行性疾病（包括帕金森氏病（PD））的关键病理生理过程。然而，线粒体缺损与神经炎症之间的相互关系还没有被很好地理解。在本研究中，我们表明受损的线粒体功能可以增强小胶质细胞中NLRP3炎性体驱动的促炎级联反应。用常见的炎症原LPS处理的原发小鼠小胶质细胞增加了NLRP3和IL-1β的表达。有趣的是，将LPS引发的小胶质细胞暴露于线粒体复合物-I抑制性农药鱼藤酮和tebufenpyrad，可特异性增强NLRP3的诱导作用，ASC斑点形成和IL-1β的前IL-1β加工呈剂量依赖性，表明线粒体损伤增强了小胶质细胞中NLRP3炎性体介导的促炎反应。神经毒性农药诱导的NLRP3炎性小体活化伴随着小胶质细胞的生物能缺陷和溶酶体功能障碍。此外，该农药增强了原发性小胶质细胞中线粒体ROS的产生，而线粒体靶向抗氧化剂线粒体丝胶蛋白改善了线粒体衍生的ROS，从而完全消除了IL-1β的释放，表明线粒体ROS驱动了小胶质细胞中NLRP3炎性体的增强。暴露于从线粒体抑制剂处理的LPS引发的小神经胶质细胞获得的条件培养基，而非未引发的细胞，在培养的原发性中脑和人多巴胺能神经元细胞（LUHMES）中诱导多巴胺能神经变性。值得注意的是，我们的PD慢性鱼藤酮啮齿动物模型的体内结果进一步支持了由于线粒体功能障碍而促炎性NLRP3炎性体信号的激活。总的来说，我们的结果表明，小胶质细胞中的线粒体损伤可以放大NLRP3炎性体信号传导，从而增强了多巴胺能神经退行性过程。