Phenotypical and functional evaluation of dendritic cells after exosomal delivery of miRNA-155

Aims: The clinical efficiency of dendritic cell (DC) therapy needs to be improved. Exosomes, as membrane nano-vesicles, carry bio-macromolecules and play essential roles in intercellular crosstalk. Here, it is proposed that tumor cell-derived exosomes could function as vehicles to deliver exogenous miRNA-155 into DCs, for simultaneous miRNA delivery and antigen priming of DCs. Following optimization of the miRNA-155 delivery, the effect of exogenous miRNA-155 overexpression on DCs is evaluated. Main methods: For this purpose, exogenous miRNA-155 was electroporated with various voltages (0.100, 0.200, and 0.300 kV) into tumor cell-derived exosomes with various concentrations, and then DCs were treated with miRNA-155 loaded exosomes. To assess the effect of miRNA-155 loaded exosomes on DCs, the expression levels of IL12p70, IFN-gamma, and IL10 in culture supernatants were measured by ELISA. Then, the expression profiles of DC surface markers, including CD11C, MHCII (I/A-I/E), CD86, CD40, and CD83 were investigated by flow cytometry. Key findings: Concerning the results, exogenous miRNA-155 can be successfully inserted into tumor cell derived exosomes. Loading conditions for tumor cell-derived exosomes were enhanced for utilization as vehicles to deliver miRNA-155 into DCs. Analysis of the surface molecule revealed that miRNA-155 can increase the expression levels of MHCII (I/A-I/E), CD86, CD40, and CD83. ELISA analysis indicates that miRNA-155 can significantly increase, the levels of IL12p70, IFN-gamma, and IL10. Significance: Finally, it can be stated that miRNA-155 could be a candidate for dendritic cell maturation. This method can be applied in the modification of target cells in in vitro studies.