Exercise-induced plasma-derived extracellular vesicles increase adult hippocampal neurogenesis

Aerobic exercise enhances cognition in part by increasing adult hippocampal neurogenesis, angiogenesis, and astrogliogenesis. Since hippocampal atrophy is a hallmark of several neurological and psychiatric conditions—including depression, PTSD, Alzheimer’s disease, and aging—understanding the mechanisms by which exercise increases neurogenesis has broad therapeutic relevance. One potential mechanism involves extracellular vesicles (EVs), lipid bilayer-enclosed particles released by multiple tissues during exercise that transport bioactive molecular cargo to distant organs, including the brain. In this study, we tested whether plasma-derived EVs from exercising mice (ExerVs) are sufficient to promote hippocampal neurogenesis, astrogliogenesis, and vascular density in sedentary mice. EVs were isolated from the plasma of sedentary or exercising C57BL/6J mice and injected intraperitoneally into sedentary recipients twice weekly for four weeks. To evaluate reproducibility, the study was conducted across two independent cohorts using identical procedures. ExerV-treated mice showed a significant increase in BrdU-positive cells in the granule cell layer compared to both PBS- and SedV-treated controls in both cohorts. Approximately 90% of these cells co-expressed NeuN, indicating neuronal differentiation, while 6% co-expressed S100β, indicating astrocyte generation. No changes were observed in vascular density across groups. These findings provide initial evidence that systemically delivered exercise-derived EVs can enhance hippocampal neurogenesis and astrogliogenesis in sedentary mice. This proof-of-concept work supports further investigation into ExerVs as a potential therapeutic strategy for conditions associated with hippocampal atrophy.