Gata3 regulates the pathogenicity of Tbet-expressing Th17 cells in EAE

Abstract

Abstract Tbet+RORgt+ Th17 cells are thought to be key players in the pathology of experimental autoimmune encephalomyelitis (EAE) and GM-CSF production has been proposed to be one mechanism through which Th17 are encephalitic. However, the mechanisms through which Csf2 expression is regulated are unclear. Based on prior work highlighting a regulatory role for Gata3 in NKp46+ ILC3s, we hypothesized that Gata3 might play an analogous role in Tbet+ Th17 cells during EAE. Profiling Gata3 expression in MOG-immunized mice revealed that Th17 cells dynamically express Gata3 during their differentiation and maintain low levels thereafter. Therefore to determine how Gata3 might affect the pathogenicity of Tbet+ Th17 cells, we utilized tamoxifen inducible Gata3 knockout (Cre-ERT2 Gata3Fl/Fl) mice as donors in a transfer EAE model. In this model, a post-immunization deletion of Gata3 resulted in a failure to generate EAE symptoms due to a five-fold reduction in GM-CSF production, despite a normal Th17 and Tbet+ Th17 cell responses. To assess how Gata3 might affect the expression of Csf2 in a cell-intrinsic manner, we isolated Cd45.1/Cd45.2 and Cre-ERT2 Gata3Fl/Fl CD4+ effector T cells from the CNS of tamoxifen or vehicle treated co-transfer recipient mice for RNAseq. Interestingly, Gata3-deficient CD4+ T cells displayed stark reductions in Bhlhe40, Egr2, and Csf2 expression in a cell-intrinsic manner, which was confirmed in follow-up experiments. Taken together, our data suggests that Gata3 promotes the pathogenicity of Tbet+ Th17 cells in EAE, possibly via regulation of Bhlhe40 and GM-CSF expression. This research was supported by the Intramural Research Program of NIAID, NIH.