Type 2 cytokines trigger eomesodermin-associated pathway conferring robust interferon-g expression in human NK cells

Abstract

Abstract Asthma encompasses a spectrum of chronic respiratory symptoms, generally associated with aberrant expression of type 2 cytokines. As many as 10% of patients are classified as having severe asthma, characterized by poor control of disease symptoms and a paradoxical mixed milieu of both type 2 (IL-4 and IL-33) and type 1 (IFN-γ) cytokines. The source of IFN-g and mechanisms driving expression of this cytokine, which can exacerbate airway hyper-responsiveness, remain poorly defined. Here, we show that in human NK-cell cultures, combined IL-4 and IL-33 stimulation triggers high expression levels of IFN-g, even in the absence of STAT4 activation by prototypical type 1 stimuli like IL-12. At picomolar concentrations, IL-4 enhanced the expression of eomesodermin (Eomes), a critical transcription factor for IFN-γ expression. We performed anti-Eomes ChIP-seq in NK cells, generating a high-quality genome-wide map of Eomes binding with robust peak counts, strong overlap with T cell datasets, and strong enrichment for the Eomes DNA binding motif. These data support a model in which Eomes interacts with the IFNG locus to promote enhanced IFNG expression in NK cells. We also performed ATAC-seq and ChIP-seq following IL-4/IL-33 stimulation to reveal changes in chromatin accessibility and Eomes binding resulting from cytokine exposure. Collectively, our results reveal a novel pathway of IFN-γ induction in type 2 diseases that could contribute to exacerbated pulmonary dysfunction in severe asthma.