The Transcription Factor ELF4 Restrains the Inflammatory Potential of CD4+ T Cells

Abstract ELF4 is a member of the ETS family of transcription factors, known to be involved in the regulation and development of immune cells. Yet, the primary function of ELF4 was unknown prior to our discovery of patients with loss-of-function mutations in ELF4 that cause the monogenic autoinflammatory disease Deficiency in ELF4, X-linked (DEX), driven by aberrant inflammation. While it has been demonstrated by our lab that global loss of ELF4 results in hyper-cytokine release in macrophages and restrains Th17 differentiation in mice, the breadth and mechanisms of CD4+ T cell regulation by ELF4 remain enigmatic. Here, we show that loss of T cell-intrinsic ELF4 leads to enhanced interferon gamma and IL-17A production upon activation of naïve CD4+ T cells and demonstrate modulation of CD4+ T cell cytokine production by ELF4 is independent of its presence during T cell development as well as extrinsic signaling in vivo. Further, absence of T cell-intrinsic ELF4 leads to decreased expression of ATF4, a master regulator of the integrated stress response demonstrated to be crucial in restraining cytokine release upon initial activation of naïve T cells. Notably, we found ELF4 binds to the promoter region of ATF4, and expression of ATF4-induced genes is significantly reduced in CD4+ T cells in the absence of ELF4 post-activation. Thus, we elucidate an essential mechanism for restraining CD4+ T cell inflammatory potential dependent on regulation of the integrated stress response by ELF4.