Background MiR-155, an essential molecule in normal immune function, which is known to be a central regulator in the immune system, plays an important role in the development and differentiation of Th17 in recent studies. Ets-1 is a significant negative regulative factor of IL-17 generated by Th17 subset. Bioinformatics analysis and experiments as well verify that Ets-1 is also the target gene of miR-155.
Objectives To elucidate the function way of miR-155 in the differentiation of Th17 cells.
Methods CD4+T cells were separated from mice spleens and cultured with interleukins which can induce CD4+T cells differentiate into Th17 cells. IL-17 was detected by flow cytometry and ELISA after transfected with miR-155 mimics or inhibitor lentviral vectors. The expression levels of miR-155, IL-17A mRNA and Ets-1 mRNA were detected using quantitative reverse transcription PCR (qRT-PCR). The effect of si-Ets and miR-155 co-function for Th17 differentiation was analyzed.
Results The CD4+T cells were divided into four groups (control untreat group, control treat group, miR-155 minics group and miR-155 inhibitor group). IL-17 was scarcely expressed and secreted in the control untreat group. IL-17 was expressed and secreted higher in the miR-155 minics group than that in the miR-155 inhibitor group and in the control treat group(P<0.01). The expression of miR-155 and IL-17A mRNA was significantly higher than that in the other three groups(P<0.05),while the expression of Ets-1 mRNA was significantly lower (P<0.05). si-Ets-2# was screened because it markedly inhibited the expression of Ets-1 mRNA among the three designed siRNAs. The expression of IL-17A mRNA was higher and the expression of Ets-1 mRNA was lower in si-Ets-2# group than that in si-Con group when si-Ets-2# or si-Con was co-transfected with miR-155 mimics or inhibitor lentiviral vectors. The expression of Ets-1 protein was lower in si-Ets-2# group than that in si-Con group by Western blot and the decrease was markedly obvious in the miR-155 minics group.
Conclusions miR-155 can induce CD4+T cells differentiate into Th17 cells by inhibiting the gene expression of Ets-1.
Disclosure of Interest None declared