Targeting the ARRDC3–DRP1 Axis via hUMSC‐Derived Exosomal CRYAB for Neuroprotection in Cerebral Ischemia/Reperfusion Injury

Cerebral ischemia/reperfusion injury (CIRI) remains a major clinical challenge due to the lack of effective neuroprotective strategies. Here, hUMSC-derived exosomes (H-Exo) were isolated and administered intranasally (15 µg/mouse/day for 3 days) in a mouse middle cerebral artery occlusion/reperfusion (MCAO/R) model. Animals were randomly assigned to three groups: Sham, MCAO/R, and H-Exo-treated MCAO/R mice. H-Exo efficiently penetrated the blood-brain barrier, accumulated within the ischemic penumbra, and was internalized by neurons and glial cells. Treatment with H-Exo markedly improved neurological function both in vivo and in vitro. Mechanistically, H-Exo inhibits neuronal ferroptosis by preserving mitochondrial dynamics and alleviating oxidative stress. Transcriptomic analysis identified ARRDC3 as a previously unrecognized ferroptosis-associated gene that was upregulated after ischemia but suppressed by H-Exo treatment. ARRDC3 exacerbates neuronal ferroptosis by promoting Drp1-dependent mitochondrial fragmentation. Proteomic profiling further identified CRYAB as an abundant exosomal cargo mediating the neuroprotective effects of H-Exo. Pharmacological inhibition of CRYAB with NCI-41356 partially reversed the anti-ferroptotic effects of H-Exo, confirming its essential role. Collectively, this study reveals the CRYAB-ARRDC3-Drp1 axis as a key regulator linking mitochondrial dynamics to ferroptosis and highlights H-Exo as a promising non-invasive therapeutic approach for ischemic stroke.