Figure 2.

Exosomes contain proteins, nucleic acids, and other substances. Their proteins include heat shock proteins (HSP70, HSP90), four-transmembrane protein superfamily proteins (CD9, CD63, CD81, CD82), ESCRT complex-related proteins (Tsg101, Alix), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), lysosomal associated membrane protein (LAMP1, LAMP2) and other proteins. Their nucleic acids include mRNA, miRNA, circRNA, DNA and so on. The other substances include specific components, which are closely related to their progenitor cells, that is, cell-specific molecules, such as MHC-II derived from antigen-presenting cells.