Figure 1: Increased expression of Tiam1 and Rac1 in murine Th17 cells.

(a) Temporal Tiam1 and Rac1 gene expression in mouse Th17 cells. Naive CD4⁺ T cells were cultured under Th17 cell polarizing conditions with recombinant IL-6 plus TGF-β1 for 0–60 h (h) and Tiam1 and Rac1 mRNA expression was assessed by Taqman PCR. Control Rorc expression is shown. (b) Immunoblots of Tiam1 and Rac1 protein expression in naive CD4⁺ polarized under Th17 conditions for the indicated time points (0–48 h). β-actin was used as internal control for protein loading. (c) Relative mRNA expression of Tiam1 and Rac1 in CD4⁺ T cells isolated from MOG_35–55-immunized IL-17A-GFP knock-in mice. IL-17A-GFP⁺ and IL-17A-GFP⁻ cells were separated by flow cell sorting from spleens of EAE mice 10 days after immunization with MOG_35–55 peptide and Tiam1 and Rac1 mRNA expression was analyzed by quantitative Taqman PCR. Control Il17a expression is shown. (d) STAT3 genetic deficiency suppressed the induction of Tiam1 expression in Th17 cells. CD4⁺ T cells were isolated from spleens of naïve STAT3KO and WT mice, T cells were differentiated under Th1 and Th17 cells for 24 h and Tiam1 mRNA expression was assessed by Taqman PCR. Data represent mean±s.e.m. of a representative experiment each performed in triplicate. *P<0.05; **P<0.01 by Student t-test. Data are representative of 2–3 biological replicates with similar results.