Changes and significances of IL-17-associated histone methylation in the acute phase of Kawasaki dis-ease / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the changes and significances of IL-17-associated histone methylation in the acute phase of Kawasaki disease (KD). Methods Forty-two children with KD and 28 age-matched healthy children were recruited in this study. Co-immunoprecipitation and real-time PCR were performed to detect the IL-17-associated histone methylation in CD4+ T cells. The percentages of CD4+IL-17+ T cells (Th17) and the expression of IL-17 and pSTAT3 at protein level were analyzed by flow cytome-try. Quantitative real-time PCR was used to measure the expression of IL-17, IL-6Rα, gp130, IL-23R, IL-23Rβ1, ETV5, SOCS1, SOCS3, TLR4, MyD88/TRIF, TNFR1 and RIP1 at mRNA level and the expres-sion of miR155 in CD4+ T cells. The levels of IL-6, IL-23 and TNF-αin plasma samples were measured by enzyme-linked immunosorbent assay. Results (1) The children with acute KD showed increased percenta-ges of Th17 cells and enhanced expression of IL-17 and H3K4me3, but inhibited expression of H3K27me3 [H3K4me3(3.79±1. 45)% vs (1. 93±0. 31)%, H3K27me3 (54. 51±13. 60)% vs (73. 96± 22. 32)%;P<0. 05]. Moreover, the three former indexes in KD patients complicated with coronary artery lesions ( KD-CAL+) were higher than those in KD patients without coronary artery lesions ( KD-CAL-) , while the levels of H3K27me3 in KD-CAL+ group were lower than those in KD-CAL- group [ H3K4me3(5. 11±1. 68)% vs (2. 98±0. 99)%, H3K27me3(45. 02±14. 83)% vs (60. 35±12. 51)%;P<0. 05]. A positive correlation was observed between the ratio of H3K4me3/H3K27me3 and IL-17 at transcriptional level in patients with acute KD (r=0. 69, P<0. 05). Treatment with intravenous immunoglobulin (IVIG) restored Th17 cells, expression of IL-17 and methylation levels of H3K4me3 and H3K27me3 to normal levels [H3K4me3(2. 44 ± 0. 77)% vs (3. 79 ± 1. 45)%, H3K27me3 (66. 52 ± 15. 73)% vs (54. 51 ± 13. 60)%;P<0. 05]. (2) The expressions of pSTAT3, ETV5 and miR155 increased significantly in pa-tients with acute KD, while the expressions of negative regulators of pSTAT3 ( SOCS1 and SOCS3 ) were down-regulated. The expressions of pSTAT3, ETV5 and miR155 in KD-CAL+ group were higher than those in KD-CAL- group (P<0. 05), while the levels of SOCS1 and SOCS3 in KD-CAL+ group were lower than those in KD-CAL- group (P<0. 05). IVIG therapy restored the indexes mentioned above to some extent (P<0. 05). (3) Compared with the healthy subjects, the levels of inflammatory cytokines (IL-6, IL-23 and TNF-α) in plasma and the expressions of surface receptors (TLR4, IL-6Rα/gp130, IL-23R/IL-23Rβ1 and TNFR1) and its downstream adaptors (MyD88, TRIF, RIP1) in CD4+T cells were up-regulated in patients with acute KD (P<0. 05), but were down-regulated significantly after IVIG treatment (P<0. 05). Moreo-ver, all of the indexes mentioned above in KD-CAL+ group were found to be higher than those in KD-CAL-group (P<0. 05). Conclusion Aberrant patterns of IL-17-associated histone methylation might be related to the immune dysfunction in patients with KD.