Human umbilical cord mesenchymal stem cell‐derived exosome suppresses programmed cell death in traumatic brain injury via PINK1/Parkin‐mediated mitophagy

Abstract Aims Recently, human umbilical cord mesenchymal stem cell (HucMSC)‐derived exosome is a new focus of research in neurological diseases. The present study was aimed to investigate the protective effects of HucMSC‐derived exosome in both in vivo and in vitro TBI models. Methods We established both mouse and neuron TBI models in our study. After treatment with HucMSC‐derived exosome, the neuroprotection of exosome was investigated by the neurologic severity score (NSS), grip test score, neurological score, brain water content, and cortical lesion volume. Moreover, we determined the biochemical and morphological changes associated with apoptosis, pyroptosis, and ferroptosis after TBI. Results We revealed that treatment of exosome could improve neurological function, decrease cerebral edema, and attenuate brain lesion after TBI. Furthermore, administration of exosome suppressed TBI‐induced cell death, apoptosis, pyroptosis, and ferroptosis. In addition, exosome‐activated phosphatase and tensin homolog‐induced putative kinase protein 1/Parkinson protein 2 E3 ubiquitin–protein ligase (PINK1/Parkin) pathway‐mediated mitophagy after TBI. However, the neuroprotection of exosome was attenuated when mitophagy was inhibited, and PINK1 was knockdown. Importantly, exosome treatment also decreased neuron cell death, suppressed apoptosis, pyroptosis, and ferroptosis and activated the PINK1/Parkin pathway‐mediated mitophagy after TBI in vitro. Conclusion Our results provided the first evidence that exosome treatment played a key role in neuroprotection after TBI through the PINK1/Parkin pathway‐mediated mitophagy.