Study of new molecular mechanism for Th9 differentiation

ABSTRACT: Th9 cells are differentiated from naïve CD4+ T cells by T cell receptor (TCR) stimulation in the presence of the cytokines transforming growth factor-beta (TGF-b) and IL-4, but the molecular mechanisms by which signaling via these two cytokines control Il9 gene expression remain incompletely understood. We show here opposing functions of albumin site D-binding protein (DBP) and E2F8, an atypical member of the E2F family member of transcription factors , in controlling Th9 cell differentiation. Specifically, TGF-b and IL-4 signaling induced phosphorylation of the Serine 213 site in the linker region of the Smad3 protein (pSmad3L-Ser213) via the activation of phosphorylated MAPK p38 (p-p38). pSmad3L-Ser213, but not the phosphorylation of the C-terminal of SMAD3 (pSmad3C), was necessary and sufficient for Il9 gene transcription. We identified DBP and E2F8 as a potential activator and repressor, respectively, for Il9 gene transcription by analyzing the global chromatin accessibility and transcriptomes and discovered that pSmad3L-Ser213 was required for the increase in DBP expression but decreased E2F8 expressions during Th9 cell differentiation. We found that while DBP and E2F8 directly bound to the promoters of Il9 gene, DBP enhanced, but E2F8 suppressed, Il9 gene transcription in CD4+ T cells in response to TGF-b and IL-4 signaling, as revealed by functional gene loss- and gain-of-function studies. Notably, the Dbp-deficient and E2f8-deficient Th9 cells promoted and suppressed tumor growth, respectively, in experimental tumor models of melanoma and fibrosarcoma in mice. Importantly, DBP and E2F8 also exhibited opposing roles in regulating human TH9 differentiation in vitro. Thus, we have revealed a previously unrecognized molecular mechanism of Smad3 linker region-mediated opposing functions of DBP and E2F8 in Th9 differentiation.

ORGANISM(S): Mus musculus

PROVIDER: GSE182472 | GEO | 2022/08/09

REPOSITORIES: GEO