Exosome is a cell-derived extracellular vesicle that contains membrane and cytoplasmic proteins, lipids, and nucleic acids. It is involved in various biological processes, including cell-to-cell communication, intercellular signaling, and waste removal. Exosomes are released from all types of cells under both normal and pathological conditions. Due to their small size (30-100 nm), exosomes can be taken up by other cells, where they deliver their contents and modulate recipient cell behavior. In recent years, exosomes have attracted considerable attention as potential diagnostic and therapeutic agents for various diseases.
The first exosomes were discovered in the late 1970s by researchers who were studying multivesicular endocytosis, a process by which large molecules are internalized into cells via membrane-bound vesicles. However, it was not until the early 2000s that exosomes were shown to be released from cells into the extracellular environment. Since then, much progress has been made in our understanding of exosome biogenesis, secretion, uptake, cargo sorting/selection mechanisms, and functions. Exosomes are now known to play important roles in diverse biological processes such as tissue homeostasis, immune response/regulation, cancer progression/metastasis etc. Given their pleiotropic effects on target cells/tissues , it is not surprising that dysregulated exosome release has been implicated in the pathogenesis of many human diseases . Elucidating the molecular mechanisms underlying these disease states will undoubtedly lead to the development of novel diagnostics and therapeutics targeting aberrant exosome function .