Abstract
Chronic hypoperfusion-induced neuronal damage is the pathological basis of vascular dementia (VD). Hypoxia enhances the paracrine effects of neural stem cells (NSCs) by promoting neuroprotection and synaptic plasticity, which may be mediated by extracellular vehicles (EVs) secretion. In this study, we aimed to investigate the therapeutic effects and underlying mechanisms of hypoxic NSC-derived EVs (hypoxic NSC-EVs) in VD. Using Co-IP and Nanoparticle Tracking Analysis (NTA), we identified HIF-1α as a hypoxic adaptor protein that binds to RAB27A, promoting the localization of RAB27A with multivesicular bodies (MVBs). This interaction enhances the secretion of NSC-EVs under hypoxic condition. By miRNA sequencing, we observed that hypoxia increased the secretion of NSC-EVs and their enrichment of miR-210. Through a series of in vivo and in vitro gain- and loss-of-function experiments, we demonstrated that hypoxic NSC-EVs were more effective than normoxic NSC-EVs in improving cognitive function, increasing neuronal survival, enhancing synaptic plasticity and dendritic spine density, and reducing neuronal ROS production and apoptosis in the cortex and hippocampus of VD mice. Additionally, hypoxic NSC-EVs promoted neuronal viability, neurite elongation, and branching in oxygen-glucose-deprived (OGD) neurons by transferring miR-210. Rescue experiments revealed that silencing SPRED1, a target gene of miR-210, restored the diminished neuroprotective effects of miR-210 knockout NSC-EVs. Our findings suggest that the HIF-1α/RAB27A axis mediates the generation of hypoxic NSC-EVs, which amplifying their effects in promoting cognitive recovery after VD through the transfer of miR-210.