Abstract
Intestinal epithelial barrier dysfunction and vitamin D (VitD)-deficiency play a critical role in a large number of diseases. The histone deacetylases (HDAC) are associated with a large number of immune diseases. This study tests a hypothesis that the interaction between VitD and HDAC is associated with the regulation of epithelial barrier functions. In this study, human intestinal epithelial cell line, T84 cells, was cultured into monolayers to be used as a model to test the epithelial barrier functions. We observed that in a VitD-deficient environment, the T84 monolayer barrier function was compromised. Exposure to calcitriol (the active form of VitD3) in the culture increased the expression of VitD receptor (VDR) in T84 cells. In a VitD-sufficient environment, VDR formed a complex with histone deacetylase-11 (HDAC11); the complex was markedly decreased in a VitD-deficient environment. We also observed that significantly more binding of HDAC11 to the promoter of the tight junction proteins inhibit the gene transcription activities of these loci in the VitD-deficient environment, which were abolished by the presence of calcitriol in the culture. In conclusion, the interaction between VDR and HDAC11 plays a crucial role in the maintenance of the epithelial barrier integrity.