Targeting Atf4 for enhanced neuroprotection: Role of quercetin-loaded EVs in ischemic stroke

This study investigates the neuroprotective potential of extracellular vesicles (EVs) delivering quercetin-3-O-β-d-glucuronic acid (QG-EVs) in cerebral ischemia-reperfusion injury (CIRI). Targeted brain delivery of QG-EVs was confirmed, with neuron cells identified as pivotal in modulating CIRI through single-cell RNA sequencing (scRNA-seq). Activating transcription factor 4 (Atf4) was highlighted as a critical regulatory factor, and in vitro studies revealed that silencing Atf4 diminished the neuroprotective effects of QG-EVs, increasing oxidative stress levels and neuronal apoptosis. In a CIRI mouse model, the knockdown of Atf4 attenuated the protective outcomes provided by QG-EVs, further affirming the role of Atf4 in mediating neuroprotection. Behavioral assessments and protein analysis showed that QG-EVs significantly reduced neuronal damage and pro-apoptotic markers, while improving neurological function via Atf4 upregulation. The outcomes hint at the potential of QG-EVs as a beneficial therapeutic modality to mitigate neuronal damage in CIRI by enhancing Atf4 expression, highlighting its potential for improving ischemic stroke outcomes.