Changes and significance of ubiquitination of Foxp3 protein during the acute phase of Kawasaki dis-ease

Abstract

Objective To investigate the changes and significance of ubiquitination of Foxp3 protein during the acute phage of Kawasaki disease (KD). Methods Forty-eight children with KD and twenty-eight age-matched healthy children were recruited in this study. Co-immunoprecipitation and Western blot assays were performed to determine the poly-ubiquitination status of Foxp3 in CD4+ T cells. The percentages of CD4+ CD25highFoxp3+ regulatory T cells (Treg) and the levels of IL-10, transforming growth factor-β (TGF-β), cytotoxic T lymphocyte-associated protein-4 (CTLA4), STIP1 homology and U-Box containing protein 1 (STUB1), heat shock protein 70 (HSP70), ubiquitin-specific-processing protease 7 (USP7) and pSTAT3 were analyzed by flow cytometry analysis. Quantitative real-time PCR was used to evaluate the transcription levels of TLR1-10, IL-1R1, IL-1RAP, IL-6Rα, gp130, TNFR1, MyD88 and RIP1 in CD4+ T cells. Plasma concentrations of IL-1β, IL-6 and TNF-α were measured by enzyme-linked immunosorbent assay. Results (1) The percentages of Treg cells and the levels of IL-10, TGF-β, CTLA4 and forkhead box P3 (Foxp3) in patients with acute KD were lower than those of healthy subjects (P 0.05). Conclusion Hyper-ubiquitination of Foxp3 protein might be involved in the immune dysfunction during Kawasaki disease. Key words: Kawasaki disease; Foxp3; Ubiquitination; Regulatory T cells; Immune regulation