Oxidative Stress Regulates IL-4 Gene Expression in Mast Cells through the Reduction of Histone Deacetylase

Abstract

Objective Many proinflammatory cytokines are regulated by the acetylation and deacetylation of the core histone. Since dysregulation of T helper 2 cytokine production is a key in the pathogenesis of allergic diseases, we examined the role of histone deacetylase (HDAC) on interleukin (IL)–4 gene expression in mast cells. We also examined whether oxidative stress has any impact on HDAC activity. Study Design In vitro study. Setting Academic research laboratory. Methods An IgE-sensitized mast cell line (RBL-2H3 cells) was treated with varying concentrations of the HDAC inhibitors trichostatin A (TSA) and H2O2 and stimulated with antigens. The amount of IL-4 gene expression was quantified by real-time polymerase chain reaction. Quantitative measurement of IL-4 in the cell supernatant was performed using enzyme-linked immunosorbent assay. Moreover, HDAC activity was measured with the use of a nonisotopic assay that utilized an HDAC Fluorescent Activity Assay Kit. Results IL-4 mRNA expression was induced by antigens in IgE-sensitized RBL-2H3 cells. Pretreatment with TSA and H2O2 enhanced IL-4 mRNA expression up to 5-fold in a dose-dependent manner. Furthermore, HDAC activity in RBL-2H3 cells was reduced after treatment with H2O2. Conclusion Our results suggest that oxidative stress may up-regulate IL-4 gene expression in mast cells via a decrease in HDAC activity.