Fig. 1

Biogenesis of mesenchymal stem cell-derived exosomes and potentially therapeutic functions of non-coding RNAs they carry. The process of exosome biogenesis involves a double invagination of the plasma membrane and the formation of intracellular multivesicular bodies (MVBs). The plasma membrane invaginates for the first time and undergoes endocytosis, generating early sorting endosomes in the cytoplasm. Early sorting endosomes can mature into late sorting endosomes, which further generate MVBs. MVBs are formed by the second invagination of the plasma membrane which can either fuse with lysosomes or autophagosomes to be degraded or fuse with the plasma membrane to release intraluminal vesicles (i.e., exosomes). CircRNA, circular RNA; LncRNA, long non-coding RNA; miRNA, microRNA; ncRNA, non-coding RNA; ROS, reactive oxygen species, TSG101, Tumor susceptibility gene 101