Endogenous Engineering Reprograms Extracellular Vesicles for Enhanced Therapeutic Function.

Extracellular vesicles (EVs) have emerged as versatile biological carriers capable of transporting diverse therapeutic cargos. Their endogenous biogenesis pathways provide unique opportunities to regulate cargo selection through both environmental modulation and genetic programming. This review outlines how EV-producing cells can be reprogrammed to load functional proteins and nucleic acids by combining environmental cues with genetic modifications that leverage intrinsic sorting machinery and engineered molecular interactions. For protein cargo, we outline strategies that reshape EV composition through physiological stimuli, as well as genetically encoded systems designed to recruit proteins via scaffold fusion, peptide tags, or fusion-independent mechanisms. For nucleic acid cargo, we highlight approaches that leverage environment-driven alterations in RNA abundance, together with targeted loading methods that rely on scaffold-RNA-binding proteins (RBPs) fusion constructs, natural sorting motifs, and sorting-related RBPs to enrich miRNAs, mRNAs, and ribonucleoprotein complexes. We further summarize recent therapeutic applications of these endogenous engineering strategies in cardiovascular, hepatic, neurological diseases, and cancer. Finally, we discuss future directions, including high-throughput discovery of sorting elements, scalable biomanufacturing, and improved standardization, which together will advance the development of programmable and clinically translatable EVs-based therapeutics.