School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China; State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environment Sciences, Shanghai 200233, China.
School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China.
Sci Total Environ. 2022 Mar 20;813:151899. doi: 10.1016/j.scitotenv.2021.151899. Epub 2021 Nov 24.
Exposure to ambient ultrafine black carbon (uBC, with aerodynamic diameter less than 100 nm) is associated with many neurodegenerative diseases. Oxidative stress is the predominantly reported neurotoxic effects caused by uBC exposure. Mitochondrion is responsible for production of majority of ROS in cells and mitochondrial dysfunction is closely related to adverse nervous outcomes. Mitophagy is an important cellular process to eliminate dysfunctional or damaged mitochondria. However, the mechanisms that modulate mitophagy and mitochondrial dysfunction initiated by uBC remain to be elucidated. The purpose of this study was to investigate how mitochondrial oxidative stress regulated mitochondrial dysfunction and mitophagy in human neuroblastoma cell line (SH-SY5Y) after uBC treatment. RNA interference was further applied to explore the roles of mitophagy in mitochondrial dysfunction. We found uBC triggered cell apoptosis via ROS-mitochondrial apoptotic pathway. The uBC also caused serious mitochondrial damage and respiratory dysfunction, indicated by the abnormalities in mitochondrial division and fusion related proteins, decreased mitochondria number and ATP level. Increased PTEN induced putative kinase 1 (PINK1) and Parkin protein levels and the autolysosome numbers suggested uBC could promote Pink1/Parkin-dependent mitophagy process in SH-SY5Y cells. Mitophagy inhibition could reserve mitochondria number and ATP activity, but not fusion and division related protein levels in SH-SY5Y cells exposed to uBC. Administration of a mitochondria-targeted antioxidant (mitoquinone) significantly eliminated uBC caused apoptosis, mitochondrial dysfunction and mitophagy. Our data suggested mitochondrial oxidative stress regulated uBC induced mitochondrial dysfunction and PINK1/Parkin-dependent mitophagy. PINK1/Parkin-dependent mitophagy probably participated in regulating uBC caused mitochondrial dysfunction but not by controlling mitochondrial fusion and division related proteins. Our results may provide some new insights and evidences to understand the mechanisms of neurotoxicity induced by uBC.
暴露于环境超细黑碳（uBC，空气动力学直径小于 100nm）与许多神经退行性疾病有关。氧化应激是 uBC 暴露引起的主要神经毒性作用。线粒体负责细胞中大部分 ROS 的产生，线粒体功能障碍与不良神经结局密切相关。自噬是消除功能失调或受损线粒体的重要细胞过程。然而，uBC 引发的自噬和线粒体功能障碍的调节机制仍有待阐明。本研究旨在探讨 uBC 处理后人神经母细胞瘤细胞系（SH-SY5Y）中线粒体氧化应激如何调节线粒体功能障碍和自噬。进一步应用 RNA 干扰探讨自噬在线粒体功能障碍中的作用。我们发现 uBC 通过 ROS-线粒体凋亡途径触发细胞凋亡。uBC 还导致严重的线粒体损伤和呼吸功能障碍，表现为线粒体分裂和融合相关蛋白异常、线粒体数量和 ATP 水平下降。PTEN 诱导的假定激酶 1（PINK1）和 Parkin 蛋白水平升高和自噬溶酶体数量增加表明 uBC 可促进 SH-SY5Y 细胞中 Pink1/Parkin 依赖性自噬过程。自噬抑制可保留 uBC 暴露的 SH-SY5Y 细胞中线粒体数量和 ATP 活性，但不能保留融合和分裂相关蛋白水平。线粒体靶向抗氧化剂（mitoquinone）的给药可显著消除 uBC 引起的凋亡、线粒体功能障碍和自噬。我们的数据表明，线粒体氧化应激调节 uBC 诱导的线粒体功能障碍和 PINK1/Parkin 依赖性自噬。PINK1/Parkin 依赖性自噬可能参与调节 uBC 引起的线粒体功能障碍，但不是通过控制线粒体融合和分裂相关蛋白。我们的结果可能为理解 uBC 引起的神经毒性的机制提供一些新的见解和证据。
