Figure 1.

Mechanism of exosomal miRNA secretion. Pri-miRNA is initially transcribed from the genome, processed by Drosha to pre-miRNA, and is then transported into cytoplasm via Exportin-5 where mature miRNA is formed. Mature miRNA is integrated into the miRISC complex and therefore targets mRNA. The P-body fuses with late endosomes and releases miRNA-containing exosomes. Exosomes are further taken up by the receptor-ligand interaction, regulating a series of gene expressions in recipient cells.