Jagged-1-HES-1 signaling inhibits the differentiation of TH17 cells via ROR gammat.

Notch signaling plays an important role in differentiation of T cells. However, little is known as to action of it in differentiation of Th17 cell subset. In this study, a soluble Jagged-1/Fc chimera protein (Jagged-1) was directly used to activate Jagged-1-Notch signaling, while Hes-1-targeting siRNA was used to knock down Hes-1 gene to investigate effect of Jagged-1-Hes-1 signaling on the differentiation of CD4+ T cells into Th17 cells. The results showed that Jagged-1 could promote the expression of Hes-1 and Deltex-1 mRNAs and the expression of NICD, Hes-1 and Deltex-1 proteins, which might be significantly blocked by DAPT, a specific inhibitor of Notch signaling. Jagged-1-Hes-1 signaling resulted in the markedly decreased in situ expression of RORgammat in the CD4+ T cells induced by IL-6 plus TGF-ß. Flow cytometric analysis showed the reduction of IL-17 production in CD4+ T cells by Jagged-1, but the enhancement of it by Hes-1-targeting siRNA. The level of IL-10 produced by the treated cells was also enhanced, whereas the expression of IL-17 was prominently attenuated, which could be offset by anti-Jagged-1 antibody or DAPT. The results indicate that Jagged-1-Hes-1 signaling can suppress the skewing of CD4+ T cells toward Th17 cells via RORgammat, for which Hes-1 may be crucial.