In Activated Murine Mast Cells, NFATc2 Is Critical for the Production of Autocrine IL-3, Thereby Promoting the Expression of IL-9

Abstract IL-9 has lent its numerical designation to the Th9 subset of CD4+ Th cells, although it is also produced by additional cell types, including mast cells. It is a pleiotropic cytokine involved in allergic reactions, parasitic infections, autoimmune inflammation, and cancer immunity. In this article, we provide evidence that NFATc2 has contradictory functions in the expression of IL-9 in murine Th9 cells and bone marrow–derived mast cells (BMMC). The basis for this is our observation that the production of IL-9 in NFATc2-deficient Th9 cells is increased, whereas it is decreased in BMMC devoid of NFATc2. In addition, NFATc2 deficiency almost completely abrogates the expression of IL-3 …