Objective: To explore the impact of oxidative insults on mitochondrial dynamics. In mammalian cells, oxidative insults activate stress response pathways including inflammation, cytokine secretion, and apoptosis. Intriguingly, mitochondria are emerging as a sensitive network that may function as an early indicator of subsequent cellular stress responses. Mitochondria form a dynamic network, balancing fusion, mediated by optic atrophy-1 (OPA1), and fission events, mediated by dynamin-related protein-1 (DRP1), to maintain homeostasis.

Methods: Here, we examine the impact of oxidative insults on mitochondrial dynamics in 143B osteosarcoma and H9c2 cardiomyoblast cell lines via confocal microscopy, flow cytometry, and protein-based analyses.

Results: When challenged with hydrogen peroxide (H₂O₂), a ROS donor, both cell lines display fragmentation of the mitochondrial network and loss of fusion-active OPA1 isoforms, indicating that OPA1-mediated mitochondrial fusion is disrupted by oxidative damage in mammalian cells. Consistent with this, cells lacking OMA1, a key protease responsible for cleavage of OPA1, are protected against OPA1 cleavage and mitochondrial fragmentation in response to H₂O₂ challenge.

Discussion: Taken together, these findings indicate that oxidative insults damage OPA1-mediated mitochondrial dynamics in mammalian cells via activation of OMA1, consistent with an emerging role for mitochondrial dynamics as an early indicator of cellular stress signaling.

Abbreviations: Δψ_m: transmembrane potential; ROS: reactive oxygen species; H₂O₂: hydrogen peroxide; OPA1: optic atrophy-1; MFN1: mitofusin1; DRP1: dynamin-related protein 1; DMEM: Dulbecco’s Modified Eagle’s Medium; PBS: phosphate buffer saline; TOM20: translocase of the outer mitochondrial membrane-20; DAPI: diaminophenylindole; TMRE: tetramethylrhodamine ethyl ester; TBST: Tris-Buffered Saline Tween-20; MEF: mouse embryonic fibroblast.

目的：探讨氧化损伤对线粒体动力学的影响。在哺乳动物细胞中，氧化损伤激活了应激反应途径，包括炎症，细胞因子分泌和细胞凋亡。有趣的是，线粒体已成为一种敏感的网络，可作为后续细胞应激反应的早期指标。线粒体形成一个动态网络，平衡由视神经萎缩1（OPA1）介导的融合和由动力相关蛋白1（DRP1）介导的裂变事件，以维持体内平衡。

方法：在这里，我们通过共聚焦显微镜，流式细胞术和基于蛋白质的分析，研究了氧化损伤对143B骨肉瘤和H9c2心肌细胞系中线粒体动力学的影响。

结果：当用过氧化氢（H ₂ O ₂），ROS供体攻击时，两种细胞系均显示线粒体网络的碎片和融合活性OPA1亚型的丢失，表明OPA1介导的线粒体融合被哺乳动物的氧化损伤所破坏。细胞。与此相一致，缺少对OMA1（负责OPA1裂解的关键蛋白酶）的细胞的保护，使其免受H ₂ O ₂攻击而导致的OPA1裂解和线粒体断裂。

讨论：总而言之，这些发现表明，氧化损伤通过激活OMA1破坏了哺乳动物细胞中OPA1介导的线粒体动力学，这与线粒体动力学作为细胞应激信号的早期指标的新兴作用相一致。

缩写：Δψ_米：跨膜电位; ROS：活性氧；H ₂ O ₂：过氧化氢；OPA1：视神经萎缩1；MFN1：mitofusin1；DRP1：动力蛋白相关蛋白1；DMEM：Dulbecco的改良版Eagle媒介；PBS：磷酸盐缓冲液；TOM20：线粒体外膜20的转位酶；DAPI：二氨基苯基吲哚；TMRE：四甲基若丹明乙酯；TBST：Tris缓冲盐水Tween-20；MEF：小鼠胚胎成纤维细胞。