Analysis of expression of different histone deacetylases in autoimmune thyroid disease.

Background Histone deacetylases (HDACs) and histone acetyltransferases (HAT) have an important role in the regulation of gene transcription as well as in the development and function of CD4 +Foxp3 + T regulatory (Treg) cells. Since others and we have previously reported that patients with autoimmune thyroid disease (AITD) show abnormalities in the levels and function of different Treg cell subsets, we decided to analyse the levels of expression of several HDACs and the Tip60 HAT in the thyroid gland and immune cells from these patients. Methods The expression of HDAC1-11 and the Tip60 HAT, at RNA and protein levels, were determined in thyroid tissue from 20 patients with AITD and 10 healthy controls and these findings were correlated with clinical data. HDAC9 and Tip60 levels were also analysed in thyroid cell cultures, stimulated or not with pro-inflammatory cytokines as well as in different cell subsets from peripheral blood mononuclear cells. Results An altered expression of different HDACs was observed in thyroid tissue from AITD patients, including a significant increase in HDAC9, at RNA and protein levels. Likewise, HDAC9 expression was increased in peripheral blood mononuclear cells particularly in Treg cells in patients with AITD. In contrast, Tip60 expression was reduced in thyroid gland samples from patients with Hashimoto thyroiditis. Conclusions Our results indicate that HDAC expression is dysregulated in thyroid gland and immune cells from patients with AITD, suggesting their involvement in the pathogenesis of this condition.