Fig. 1

Biogenesis of Exosomes: Exosomes are formed through the invagination of the plasma membrane in two phases. a The first phase involves budding formation, which incorporates cell surface proteins, extracellular soluble proteins, and other small molecules, resulting in the formation of early sorting endosomes (ESE). ESEs then mature and convert into late-sorting endosomes (LSE). The second phase involves inward budding of the endosomal limiting membrane, which incorporates constituents from the endoplasmic reticulum (ER), trans-Golgi network (TGN), as well as small biomolecules such as nucleic acids and mitochondria. This process leads to the formation of multivesicular bodies (MVBs). Subsequently, intracellular vesicles (exosomes) are gradually released into the microenvironment after MVBs fuse with the plasma membrane. Additionally, MVBs can fuse with lysosomes or autophagosomes for the degradation of their contents, which can be recycled by the cells. b The structure of exosomes: Exosomes contain a wide range of molecules, including nucleic acids, proteins, metabolites, and lipids. Both the membrane-bound components and the soluble components of exosomes represent the cellular origin from which they were released