The polycomb protein Ezh2 regulates differentiation and plasticity of CD4 T helper type-1 and type-2 cells.. Mus musculus

Following antigen encounter by CD4 T cells, polarizing cytokines induce the expression of master regulators that control differentiation. Inactivation of the histone methyltransferase Ezh2 was found to specifically enhance T-helper (Th)1 and Th2 cell differentiation and plasticity. Ezh2 directly bound and facilitated correct expression of Tbx21 and Gata3 in differentiating Th1 and Th2 cells, accompanied by substantial tri-methylation at lysine 27 of histone 3 (H3K27-Me3). In addition, Ezh2 deficiency resulted in spontaneous generation of discrete IFN-γ and Th2 cytokine-producing populations in non-polarizing cultures, and under these conditions IFN-γ expression was largely dependent on enhanced expression of the transcription factor Eomesodermin. In vivo, Loss of Ezh2 caused increased pathology in a model of allergic asthma and resulted in progressive accumulation of memory phenotype Th2 cells. This study establishes a functional link between Ezh2 and transcriptional regulation of lineage-specifying genes in terminally differentiated CD4 T cells. Overall design: Wild type and Ezh2 knock out unpolarized Th cells, Th1 cells and Th2 cells are profiled for mRNA expression