JunB is essential for IL-23-dependent pathogenicity of Th17 cells.

Hasan, Zafrul; Koizumi, Shin-Ichi; Sasaki, Daiki; Yamada, Hayato; Arakaki, Nana; Fujihara, Yoshitaka; Okitsu, Shiho; Shirahata, Hiroki et al. · Nat Commun · 2017

basic_science · Level V

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Abstract

CD4<sup>+</sup> T-helper cells producing interleukin-17 (IL-17), known as T-helper 17 (T<sub>H</sub>17) cells, comprise heterogeneous subsets that exhibit distinct pathogenicity. Although pathogenic and non-pathogenic T<sub>H</sub>17 subsets share a common RORγt-dependent T<sub>H</sub>17 transcriptional programme, transcriptional regulatory mechanisms specific to each of these subsets are mostly unknown. Here we show that the AP-1 transcription factor JunB is critical for T<sub>H</sub>17 pathogenicity. JunB, which is induced by IL-6, is essential for expression of RORγt and IL-23 receptor by facilitating DNA binding of BATF at the Rorc locus in IL-23-dependent pathogenic T<sub>H</sub>17 cells, but not in TGF-β1-dependent non-pathogenic T<sub>H</sub>17 cells. Junb-deficient T cells fail to induce T<sub>H</sub>17-mediated autoimmune encephalomyelitis and colitis. However, JunB deficiency does not affect the abundance of gut-resident non-pathogenic T<sub>H</sub>17 cells. The selective requirement of JunB for IL-23-dependent T<sub>H</sub>17 pathogenicity suggests that the JunB-dependent pathway may be a therapeutic target for autoimmune diseases.

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