Bioactive Extracellular Nanovesicles
The living cells of animals, plants and micro-organisms including bacteria and fungi produce extracellular vesicles (EVs) such as microvesicles, exosomes and exomeres through endosomal pathways and derived from the plasma membrane. During EV biogenesis, cells selectively assemble lipid, protein and nucleic acid contents within the nascent nanovesicles. The bioactivity of EVs depends on their protein and nucleic acid contents. The lipid content constitutes the bilayer membrane that protects protein and RNA molecules from degradation in transit and facilitates biodistribution across tissue barriers such as the blood-brain barrier and into
solid tissue masses like tumors. The specific lipid, protein and nucleic acid content of EVs depends on the parent cell type and tissue environment, which correspondingly defines their biological effects. Localization to specific tissues and endocytosis of EVs by specific cell types is determined in part by the composition of the EV membrane and its associated proteins. Each of these intrinsic biological characteristics of EVs can be further developed into enhanced cellular targeting and bioactivity in drug development. Analytical methods that precisely identify EV contents can also provide the framework for more sensitive and accurate diagnostic tests.