Morphine reprograms brain-derived extracellular vesicle cargo associated with synaptic remodeling in the prefrontal cortex.

Extracellular vesicles (EVs) released by neurons and glia mediate intercellular communication and regulate synaptic and stress-related signaling in the brain. While chronic opioid exposure induces extensive neuroadaptations, the contribution of brain-derived EVs (BDEVs) remains poorly understood. Here, we isolated BDEVs from the prefrontal cortex of rats chronically exposed to morphine and performed integrated transcriptomic and proteomic profiling of EV cargo. Total RNA sequencing and unbiased proteomics identified morphine-associated changes enriched for pathways related to synaptic plasticity, endoplasmic reticulum stress, mitochondrial function, and neurodegeneration. Notably, the synaptic plasticity regulator Arc was increased at the mRNA level, and the ER stress marker Hspa5 was upregulated at both transcript and protein levels. Morphine-derived BDEVs induced transcriptional alterations in naïve cortical neurons, including changes in genes linked to synaptic remodeling and excitability. These findings suggest that BDEVs may contribute to opioid-induced neuroadaptations.