Molecular Mechanisms of Extracellular Vesicle Biogenesis and Their Impact on the Design of Custom EVs

Extracellular Vesicles (EVs) are nanosized lipid-bound particles that are pivotal for intercellular communication and actively participate in diverse physiological processes, including immune modulation, proteostasis, and tissue repair. EVs have emerged as promising therapeutic targets and biomarkers because of their significant roles in the pathogenesis of diseases, including cancer, neurodegeneration, and cardiovascular disorders. Despite extensive research on EVs as diagnostic tools and mediators of cellular signaling, the fundamental mechanisms underlying their biogenesis remain unclear. Consequently, this understanding of how the composition of EVs dynamically changes in response to physiological and pathological conditions is often limited, leading to lower diagnostic utility and slower advancements in clinical interventions and EVs engineering. This review explores the intricate mechanisms underlying EVs biogenesis and payload selection, emphasizing how these processes vary across EVs subclasses, thereby underpinning their functional versatility. The biogenetic pathways are highlighted from the ectocytosis-driven generation of microvesicles and apoptotic body (ApoBDs) formation via membrane blebbing to the formation of exosomes within the endosomal compartments and their regulated release via exocytosis.