Mitochondrial Superoxide is the Key for Promoting Cell Migration in Wound Healing

Introduction: The focus of current study was to investigate the role of mitochondrial superoxide for promoting cell migration in healing responses. Methods: To simulate the skin wound healing process, scratch wound assay in A549 cells was utilized. Subsequently, mitochondrial superoxide and intracellular calcium flux (Ca2+) were measured by MitoSox red reagent and Fluo-4 staining. Paraquat (PQ), N-acetyl cysteine (NAC), superoxide dismutase (SOD) mimics (EUK-134), free radical scavenge (MCI-186), and diphenyliodonium (DPI) were added into medium to evaluate the influences of reactive oxygen species (ROS) and superoxide on cell migration. Results: Compared with before wound (BW), mitochondrial superoxide increased time-dependent manner. Correspondingly, Ca2+ transients was rapidly elevated after scratch wound and gradually declined toward an steady level, as evidenced by Fluo-4 fluorescence intensity. Scratch wound assay displayed that cell migration in PQ 0.1 mM group was stronger than that of Control group, whilst it was restrained after administration of 10 mM NAC. Additionally, cell migration in EUK-134 and MCI-186 group was conspicuously lower than that of Control group and similar with the degree of inhibiting role of DPI, indicating that mitochondrial superoxide served the crux influence on promoting cell migration after scratch. Conclusion: ROS and superoxide production during scratch wound facilitated cell migration. Importantly, mitochondrial superoxide played the positive effects on healing response.