Neuron-Enriched Extracellular Vesicle MicroRNAs Reflect Hormone-Sensitive Neural Pathway Changes from Early to Late...

The menopausal transition represents a major neuroendocrine shift marked by declining estradiol and progesterone, rising follicle-stimulating hormone, and increased vulnerability to cognitive and affective symptoms. Despite extensive evidence of hormone-related neural changes, few biomarkers directly index hormone-sensitive neuronal adaptations in vivo. Neuron-enriched extracellular vesicles (nEVs) isolated from blood provide a minimally invasive window into central nervous system (CNS) biology by carrying microRNAs (miRNAs) linked to neuronal regulatory processes. This pilot study tested whether L1 cell adhesion molecule (L1CAM)-positive nEV miRNA profiles differ between early (STRAW stage -2; n = 22) and late (STRAW stage -1; n = 24) perimenopause. A pooled discovery screen of 179 miRNAs identified 10 candidates with substantial fold-change differences between groups; these were then quantified at the individual level using qPCR. Linear mixed-effects models showed a significant main effect of STRAW stage, with late perimenopause associated with higher ΔCq values (lower overall expression) across the miRNA panel. The miRNA × STRAW stage interaction was not significant, indicating a coordinated shift across the measured miRNAs rather than miRNA-specific regulation. No evidence of an association between nEV miRNA expression and current estradiol levels or menopausal symptom severity was observed. Bioinformatic analysis of predicted mRNA targets identified significant enrichment of the gonadotropin-releasing hormone (GnRH) receptor pathway, along with related growth factor, immune, and intracellular signaling pathways, with preferential expression in brain-relevant tissues. These findings are consistent with stage-related differences in hormone-sensitive neuronal regulatory processes across the transition.