Roles And Mechanisms Of MicroRNA-155 On BMSCs' Capability Of Immune Tolerance Induction

Objective:We aimed to investigate the ability of miR-155 differently expressed in bone marrow derived mesenchymal stem cells(BMSCs)to induce immune tolerance by inducing dendritic cells(DCs).Method:The experiment was divided into Control,miR-155 agomir NC,miR-155 agomir,miR-155 antagmir NC and miR-155 antagomir groups.Part I,the expression of miR-155 was specifically regulated by liposome transfection,and we detected the efficiency of transfection,the expression level of miR-155.Part II,the transfected BMSCs induced DCs for 48 hours in Transwell chamber.We detected the maturation and migration of DCs.Western Blot was used to detect the signal transduction pathways such as AKT and NF-?B(P65)in DCs after induction.Part III,the induced DCs were co-cultured with spleen-derived mononuclear cells for 72 hours in the Transwell chamber.Flow cytometry was used to detect the proliferation of T cells and the proportion of T Cell subsets.Real-time Quantitative PCR was used to detect the expression of cytokines such as IL-12 a.Results:Part ?: The expression of surface markers CD90,CD105,CD73 and CD44 in isolated BMSCs were positive while the expression of CD31 and CD45 were negative.The transfection efficiency of liposome transfected BMSCs was high,miR-155 expression in miR-155 agmimir group was increased 10,000-fold versus control group,while miR-155 antagomir group was significantly lower than that in miR-155 antagomir NC group(P=0.0014,P<0.05).Part ?: After inducing for 48 hours,the expression levels of CD40 and CD86 on the surface of the DCs in the miR-155 agomir group were significantly decreased(P<0.05),and the migration ability was significantly lower than that in the control group(P=0.0054,P<0.05).The expression levels of AKT and NF-?B(P65)signaling pathways were significantly decreased(P<0.05).The migration ability of miR-155 antagomir DCs was slightly increased(P=0.0114,P<0.05).while the AKT and NF-?B signaling pathways had no significant change in protein expression(P>0.05).Part III: After stimulation of T cells for 72 hours,the proliferation ability of T cells in the miR-155 agomir group was significantly lower than that in the control group,the proportion of Th1 cell subsets was significantly lower(P=0.0106,P<0.05),and the proportion of Treg cells was significantly higher(P=0.0005,P<0.05).The expression of IL-12 a associated RNA in T cells was significantly decreased(P=0.0311,P<0.05).Conclusion:The ability of BMSCs inducing immune tolerance may be improved while the expression of micro RNA-155 was increased,by inducing DCs to inhibit the proliferation of T cells and the differentiation of T cells into Th1 subtype.