Memory T cells provide long-lasting protective immunity, and distinct subpopulations of memory T cells drive chronic inflammatory diseases such as asthma. Asthma is a chronic allergic inflammatory disease with airway remodeling including fibrotic changes. The immunological mechanisms that induce airway fibrotic changes remain unknown. We found that interleukin-33 (IL-33) enhanced amphiregulin production by the IL-33 receptor, ST2 memory T helper 2 (Th2) cells. Amphiregulin-epidermal growth factor receptor (EGFR)-mediated signaling directly reprogramed eosinophils to an inflammatory state with enhanced production of osteopontin, a key profibrotic immunomodulatory protein. IL-5-producing memory Th2 cells and amphiregulin-producing memory Th2 cells appeared to cooperate to establish lung fibrosis. The analysis of polyps from patients with eosinophilic chronic rhinosinusitis revealed fibrosis with accumulation of amphiregulin-producing CRTH2CD161CD45ROCD4 Th2 cells and osteopontin-producing eosinophils. Thus, the IL-33-amphiregulin-osteopontin axis directs fibrotic responses in eosinophilic airway inflammation and is a potential target for the treatment of fibrosis induced by chronic allergic disorders.

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ST2hi memory-type Th2 cells are identified as a pathogenic subpopulation in eosinophilic airway inflammation. These ST2hi pathogenic Th2 cells produce large amount of IL-5 upon T cell receptor stimulation, but not in response to IL-33 treatment. By contrast, IL-33 alone induces cytokine production in ST2+ group 2 innate lymphoid cells (ILC2). Here we show that a MAPK phosphatase Dusp10 is a key negative regulator of IL-33-induced cytokine production in Th2 cells. In this regard, Dusp10 is expressed by ST2hi pathogenic Th2 cells but not by ILC2, and Dusp10 expression inhibits IL-33-induced cytokine production. Mechanistically, this inhibition is mediated by DUSP10-mediated dephosphorylation and inactivation of p38 MAPK, resulting in reduced GATA3 activity. The deletion of Dusp10 renders ST2hi Th2 cells capable of producing IL-5 by IL-33 stimulation. Our data thus suggest that DUSP10 restricts IL-33-induced cytokine production in ST2hi pathogenic Th2 cells by controlling p38-GATA3 activity.

Host lipid metabolism and viral responses are intimately connected. However, the process by which the acquired immune systems adapts lipid metabolism to meet demands, and whether or not the metabolic rewiring confers a selective advantage to host immunity, remains unclear. Here we show that viral infection attenuates the expression of genes related to lipid metabolism in murine CD4+ T cells, which in turn increases the expression of antiviral genes. Inhibition of the fatty acid synthesis pathway substantially increases the basal expression of antiviral genes via the spontaneous production of type I interferon (IFN). Using a combination of CRISPR/Cas9-mediated genome editing technology and a global lipidomics analysis, we found that the decrease in monounsaturated fatty acid caused by genetic deletion of Scd2 in mice was crucial for the induction of an antiviral response through activation of the cGAS-STING pathway. These findings demonstrate the important relationship between fatty acid biosynthesis and type I IFN responses that enhances the antiviral response.