immunomodulatory effects of calcitriol through dna methylation alteration of foxp3 in the cd4+ t cells of mice

Vitamin d plays a variety of physiological functions, such as regulating mineral homeostasis. more recently, it has emerged as an immunomodulator player, affecting several types of immune cells, such as regulatory t (treg) cells. it has been reported that vitamin d exerts some mediatory effects through an epigenetic mechanism. in this study, the impacts of calcitriol, the active form of vitamin d, on the methylation of the conserved non-coding sequence 2 (cns2) region of the forkhead box p3 (foxp3) gene promoter, were evaluated. fourteen c57bl/6 mice were recruited in this study and divided into two intervention and control groups. the cd4+ t cells were isolated from mice splenocytes. the expression of foxp3, il-10, and transforming growth factor-beta (tgf-β1) genes were relatively quantified by real-time pcr technique, and the dna methylation percentage of every cpg site in the cns2 region was measured individually by bisulfite-sequencing pcr. vitamin d intervention could significantly (p<0.05) increase the expression of foxp3, il-10, and tgf-β1 genes in the cd4+ t cells of mice comparing with the control group. meanwhile, methylation of the cns2 region of foxp3 promoter was significantly decreased in three of ten cpg sites in the vitamin d group compared to the control group. the results of this study showed that vitamin d can engage the methylation process to induce foxp3 gene expression and probably treg cytokines profile. further researches are needed to discover the precise epigenetic mechanisms by which vitamin d modulates the immune system.