Fig. 1

Sorting process for exosomal miRNAs. MiRNA genes undergo transcription into primary miRNAs (pri-miRNAs) by Pol-II, followed by processing by the DGCR8 and Drosha complex for the formation of precursor miRNAs (pre-miRNAs), which are exported into the cytosol by the exportin 5 complex. Then, pre-miRNAs undergo digestion by the Dicer complex into mature miRNAs, which are sorted into exosomes through five potential pathways: 1. nSMase2-dependent pathway; 2. 3′ miRNA sequence-dependent pathway; 3. miRNA motif and sumoylated hnRNPs-dependent pathway; 4. MiRNAISC-related pathway.5. Ceramide related pathway