Open AccessDichotomous response to transforming growth factor β after T cell receptor activation by naive CD4+ T cells from DBA/1 mice: Enhanced retinoic acid receptor–related orphan nuclear receptor γt expression yet reduced FoxP3 expression
Author(s) -
Morita Yoshiaki,
Ismail Doaa M.,
Elkon Keith B.,
Chu CongQiu
Publication year - 2011
Publication title -
arthritis & rheumatism
Language(s) - English
Resource type - Journals
eISSN - 1529-0131
pISSN - 0004-3591
DOI - 10.1002/art.27759
Subject(s) - foxp3 , cd28 , retinoic acid , t cell , t cell receptor , biology , microbiology and biotechnology , il 2 receptor , cytotoxic t cell , cytokine , orphan receptor , cd3 , transcription factor , cd8 , immunology , immune system , cell culture , biochemistry , genetics , gene , in vitro
Objective To investigate the molecular mechanism for biased interleukin‐17 (IL‐17) production by DBA/1 CD4+ T cells upon T cell receptor (TCR) and transforming growth factor β (TGFβ) stimulation. Methods Purified naive CD4+ T cells were stimulated with anti‐CD3/CD28 under Th1, Th2, Th17, and induced T regulatory (iTreg) cell conditions. Cytokine production was assayed by intracellular staining and enzyme‐linked immunosorbent assay. Expression of transcription factors was determined by reverse transcription–polymerase chain reaction, flow cytometry, and immunoblotting techniques. Results Naive CD4+ T cells from DBA/1 mice produced more IL‐17 under Th17 cell polarizing conditions as compared with those from C57BL/6 or BALB/c mice. Further investigation revealed no difference among the strains in terms of CD4+ T cell survival, upstream TCR signaling, or CD69 expression or in the phosphorylation of STAT‐3 and expression of suppressor of cytokine signaling 3 that positively or negatively regulate IL‐17 cell production. However, DBA/1 CD4+ T cells expressed increased levels of retinoic acid–related orphan receptor γt (RORγt). Furthermore, under iTreg cell polarizing conditions, DBA/1 CD4+ T cells showed a strikingly reduced level of FoxP3 expression. When interferon‐γ and IL‐4 were blocked, FoxP3 expression increased but remained lower in DBA/1 CD4+ T cells following exposure to TGFβ as compared with C57BL/6 CD4+ T cells. Moreover, DBA/1 CD4+ T cells showed reduced phosphorylation of Smad2 and Smad3 under both Th17 and iTreg cell polarizing conditions. Conclusion These results indicate that naive CD4+ T cells from DBA/1 mice have a dichotomous response to TGFβ: enhanced RORγt, yet reduced FoxP3, up‐regulation. This observation may help to elucidate the branch point of TGFβ signaling that leads to skewed Th17, but reduced iTreg, cell differentiation.