Uncovering the dynamics of extracellular vesicle microRNA trafficking in multiple sclerosis: delivery, diversion and retention.

Extracellular vesicles (EVs) are phospholipid-bound structures that carry a distinct repertoire of short, non-coding microRNAs (miRNAs). EV miRNA content differs across various diseases, including multiple sclerosis (MS). These observations may indicate a functional role for EV miRNAs in disease pathology. However, the role of EVs in miRNA trafficking remains a subject of debate. This review proposes a theoretical framework to understand the dynamics of EV miRNA trafficking in MS. Three modes of EV miRNA trafficking are presented: (i) delivery of miRNA to target cells; (ii) diversion of miRNA away from its target; or (iii) retention of the miRNA in the parent cell. This model accounts for the heterogeneity and functional diversity of EVs and may facilitate the identification of physicochemically distinct subpopulations with selective roles in miRNA transfer.