miR-150-3p enhances neuroprotective effects of neural stem cell exosomes after hypoxic-ischemic brain injury by targeting CASP2.

Brains are vulnerable to ischemic/hypoxic damage, which are directly caused by stroke, hypoxic-ischemic encephalopathy and other cerebral diseases. Currently, therapeutic strategies against cerebral ischemia and hypoxia are extremely limited. Recent studies have indicated that stem cell-derived exosomes play a neuroprotective role in hypoxic-ischemic brain injury. However, the treatment mechanism remains unclear. In this study, we cultured neural stem cells (NSCs) in vitro successfully. Exosomes isolated from NSCs (NSCs-Ex) inhibited the apoptosis while promoting the proliferation of SH-SY5Y cells both in normal and oxygen-glucose deprivation (OGD) culture conditions. Moreover, in vivo studies demonstrated that NSCs-Ex significantly reduced the infarction area in the middle cerebral artery occlusion (MCAO) model and suppressed the apoptosis of neurons. Furthermore, miR-150-3p was identified as the most abundantly expressed miRNA in exosomes compared to their parent NSCs. The miR-150-3p mimic displayed neuroprotective effects while miR-150-3p inhibitor exacerbated nerve injury both in vivo and in vitro. We further identified CASP2 as a miR-150-3p target. Thus, our data indicate that NSC-Ex facilitate the neuroprotective effects via transfer of miR-150-3p which targets CASP2, thus suppressing neuronal apoptosis after brain injury. Our results suggest that NSCs-Ex prevent cerebral injury by transferring miR-150-3p which promotes neurons proliferation by inhibiting CASP2 signaling pathway.