Effects of p300/CBP on histone acetylation of Foxp3 gene in children with Kawasaki disease

Objective To investigate the effects of p300/CBP on histone acetylation of Foxp3 gene and its roles in the immunological pathogenesis of Kawasaki disease (KD). Methods Forty-six children with KD and twenty-eight age-matched health children were consented to participate in this study. Co-immunoprecipitation and real-time PCR were performed to detect Foxp3-associated acetylation levels of histone H4 and binding abilities of p300, CBP, pSmad3 (phosphorylated mothers against decapentaplegic homolog 3) and NF-AT (nuclear factor of activated T cells) with Foxp3 gene in CD4+ T cells. The percentages of CD4+ CD25high Foxp3+ cells (Treg) and the expression of Foxp3, CTLA4 (cytotoxic T-lymphocyte-associated protein 4), p300, CBP, TGF-βRⅡ (transforming growth factor β receptor Ⅱ) and pLAT1 at protein level were analyzed by flow cytometry. Quantitative real-time PCR was used to measure the expression of Foxp3, IL-10, TGF-β, TGF-βRⅠ, Egr-1 (early growth response protein 1), RARα (retinoic acid receptor α) and PLCγ1 (phospholipase C-γ1) in Treg cells at mRNA level. Plasma concentrations of TGF-β and retinol acid (RA) were measured by enzyme-linked immunosorbent assay. Results (1) The percentages of Treg cells, levels of Foxp3 and molecules associated with suppressive function of Treg cells (TGF-β, IL-10 and CTLA4), acetylation levels of histone H4 associated with promoter, conserved non-coding DNA sequence 1 (CNS1) and CNS2 of Foxp3 gene decreased remarkably during acute KD (P 0.05). (2) The levels of p300 and CBP in Treg cells and their binding abilities with Foxp3 gene were down-regulated significantly during acute KD (P 0.05). Conclusion Hypoacetylation of histone H4 associated with Foxp3 gene caused by insufficient expression of p300/CBP and their impaired binding abilities might be involved with immune dysfunction in KD. IVIG therapy regulates the expression of p300/CBP and their binding abilities with Foxp3 gene through up-regulating TGF-β signal. Key words: Kawasaki disease; Foxp3; Histone acetylation; Regulatory T cell; Immunity