Exosomal PINK1 from Human Umbilical Cord Mesenchymal Stem Cells Attenuates Neurological Deficits and Inflammatory Responses after Intracerebral Hemorrhage in Mice.

This study investigated the therapeutic potential of exosomes from human umbilical cord mesenchymal stem cells (huMSCs), focusing on PTEN-induced kinase 1 (PINK1) and its impact on exosome efficacy. Postmodification, exosomes were administered to a murine model of intracranial hemorrhage (ICH). Assessments included brain edema, neurological function, anxiety-like behaviors, inflammatory responses, and microglial polarization. We observed that administration of exosomes from control huMSCs significantly reduced brain water content, indicating a reduction in brain edema, as quantitatively assessed through water content analysis. Neurological function, evaluated using a standard scoring system, showed marked improvement in animals treated with control exosomes compared with those receiving PINK1-deficient exosomes, highlighting the importance of PINK1 in mediating neurological recovery. Additionally, control exosomes substantially decreased anxiety-like behaviors in the Open Field Test, demonstrated by reduced immobility times and increased exploratory behavior. Inflammatory response assessments showed a favorable shift with decreased levels of pro-inflammatory cytokines (MCP-1, IL-1β, TNF-α) and increased levels of the anti-inflammatory cytokine IL-10 in the exosome-treated groups. Furthermore, analysis of microglial polarization revealed a shift toward the anti-inflammatory M2 phenotype, evidenced by decreased M1 markers (Cd86, Iba1) and increased M2 markers (Arg1, Cd206) in the control exosome-treated group. Taken together, we found that PINK1-deficient exosomes showed reduced therapeutic efficacy in ICH treatment compared with the exosomes with normal PINK1 expression. Our findings underscore the critical role of PINK1 in enhancing the therapeutic potential of huMSC-derived exosomes in ICH treatment.