Histone deacetylase inhibitor regulates the balance of Th17/Treg in allergic asthma

Background and Aims The aim of this study is to investigate the expression pattern of histone deacetylase 9 in peripheral blood of patients with allergic asthma and its regulatory effect on the balance of Th17/Treg cells involved in the pathogenesis of asthma. Methods flap-Ub promoter-GFP-WRE vector was used to construct the Jurkat-HA-FOXP3 cell line. After histone deacetylase inhibitor-trichostatin A (TSA) treatment, FOXP3 and RORγt expression were detected by real-time-polymerase chain reaction (RT-PCR). BALB/c mice were randomly assigned to control group, TSA treatment and the asthma group. Serum Immunoglobulin E (IgE) was detected with enzyme-linked immunosorbent assay (ELISA), airway inflammation in lung tissue evaluated by haematoxylin/eosin staining, bronchoalveolar lavage fluid (BALF) cell number and differential counted, interleukin (IL)-17A and TGF-β concentrations in BALF measured with ELISA, and expression of RORγt and FOXP3 messenger RNA (mRNA)measured by RT-PCR. Forty-seven patients with asthma were recruited and assigned to intermittent, mild and moderate–severe group. GATA3, IL-4, histone deacetylases (HDAC) 9 mRNA expression level were measured by RT-PCR. Results After TSA treatment, FOXP3 mRNA level was upregulated, while RORγt mRNA level was downregulated. FOXP3 protein level was also upregulated by TSA. In vivo, TSA treatment can inhibit IL-17 but promote transforming growth factor-beta production in the BALF of asthma mice, and inhibited the expression of Th17 cells and RORγt mRNA in lung; also can promote Foxp3 mRNA expression. GATA3, IL-4 mRNA expression levels were upregulated in patients with asthma than the healthy control. HDAC9 mRNA expression level was associated with the severity of disease. Conclusion The histone deacetylase inhibitor TSA can regulate the balance of Th17/Treg in asthma by regulating the activity of histone deacetylase.