MPO/HOCl upregulates gene expression of mitophagy in murine macrophages

HOCl, the main product of myeloperoxidase in vivo, could induce extensive cell damage, however, how HOCl regulates gene transcription remains unclear. In this study, we treated murine macrophage cell line with different concentrations of HOCl to clarify the regulatory role of MPO on inflammatory environment. Results showed that HOCl could induce the upregulation of autophagy-related genes and extensive changes on mitochondria-related gene expression. These results were validated by other experiments, like RT-qPCR and WB. And we also observed that HOCl could induce colocalization of autophagosomes and mitochondria in confocal images, showing mitophagy. These results were consistent with in vivo experiments showing that macrophage mitophagy was MPO-dependent. One interesting result in our study was that the vehicle of HOCl treatment, HBSS, and the sublethal HOCl could also regulate macrophage function, which was mostly ignored by HOCl-related studies.