Brain-targeted heptapeptide-loaded exosomes attenuated ischemia–reperfusion injury by promoting the transfer of healthy mitochondria from astrocytes to neurons

BACKGROUND: The exchange of mitochondria reportedly plays an important role in cell–cell communication in the central nervous system (CNS). The transfer of fragmented and dysfunctional astrocytic mitochondria into neurons and subsequent mitochondrial fusion often cause serious neuronal damage and cerebral ischaemic injury. METHODS: In this study, we prepared macrophage-derived exosomes laden with heptapeptide (Hep) as a dynamin-related protein-1 (Drp1)–fission 1 (Fis1) peptide inhibitor P110 to alleviate cerebral ischemia–reperfusion injury by reducing mitochondrial Drp1/Fis1 interaction-mediated astrocytic mitochondrial disorder and promoting the transfer of astrocyte-derived healthy mitochondria into neurons. RESULTS: The results demonstrated that Hep-loaded macrophage-derived exosomes (EXO-Hep) reduced mitochondrial damage in astrocytes by inhibiting the Drp1/Fis1 interaction after ischemia–reperfusion, ensuring the release of heathy astrocytic mitochondria and their subsequent transmission to neurons, alleviating mitochondria-mediated neuronal damage. CONCLUSION: EXO-Hep significantly mitigated ischemic injury in a model of transient middle cerebral artery occlusion (tMCAO) by reducing the infarct area and improving neurological performance during the process of cerebral ischemia–reperfusion. GRAPHICAL ABSTRACT: [Image: see text]