Effects of SMYD3 and MLL5 on histone methylation of Foxp3 gene in children with Kawasaki disease
10.3760/cma.j.issn.1007-7480.2017.08.004
- VernacularTitle:包含SET和MYND结构域的蛋白3系别混合型白血病基因5对急性期川崎病叉头螺旋翼状转录因子3基因组蛋白甲基化的影响
- Author:
Jiehua MEI
;
Qin WANG
;
Guobing WANG
;
Pengqiang WEN
;
Mingguo XU
;
Gen TANG
;
Dong CUI
;
Cong LIU
;
Dongli MA
;
Chengrong LI
- Keywords:
Mucocutaneous lymph node syndrome;
T-lymphocytes,Regulatory cells;
Transcription factor forkhead box protein 3;
Immune
- From:
Chinese Journal of Rheumatology
2017;21(8):518-523
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the effects of SMYD3 and MLL5 on histone methylation of Transcription factor forkhead box protein 3 (Foxp3) gene and its roles in the immunological pathogenesis of Kawasaki disease (KD). Methods Forty-two children with KD and 26 age-matched healthy children were consented to participate in this study. Co-Immunoprec-ipitation and real-time polymerase chain reaction (PCR) was performed to determine Foxp3-associated histone methylation levels of H3K4me3 and H3K27me3, and binding levels of SMYD3 and MLL5 with Foxp3 gene in CD4+T cells. The proportion of CD4+CD25high Foxp3+cells (Treg) and protein levels of Foxp3, cytotoxic T lymphocyte associated antigen-4 (CTLA4), TGF-βRⅡand pSmad3 were analyzed by flow cytometry. Quantitative real-time PCR was used to evaluate levels of Foxp3, interleukin (IL)-10, GITR, TGF-βRⅠand RARαmRNA in CD4+T cells. Plasma concentrations of TGF-βand retinol acid (RA) were measured by enzyme-linked Immunosorbent assay. Independent-samples t-test was used as the statistical method in this study. Results ① The proportion of Treg, expression levels of Foxp3 and molecules associated with suppressive function of Treg cells(IL-10, GITR and CTLA4), and histone methylation levels of H3K4me3 associating with promoter, conserved non-coding DNA sequence (CNS) 1 and CNS2 of Foxp3 gene decreased remarkably during acute KD [Promoter:(5.4±1.8)%vs (9.1±2.2)%;CNS1:(2.6±0.9)% vs (3.8±1.1)%; CNS2: (2.4±0.8)% vs (4.2±1.0)%; t=5.50, 6.02, 9.56, 7.92, 7.97, 4.76, 7.73, 5.01, 8.66; P<0.05], and restored after intravenous immunoglobulins (IVIG) therapy [Promoter: (7.2 ±2.1)% vs (5.4 ±1.8)%; CNS1:(3.6±1.4)% vs (2.6±0.9)%; CNS2: (3.6±1.4)% vs (2.4±0.8)%; t=5.56, 4.59, 7.01, 6.04, 5.89, 4.83, 4.45, 4.00, 5.12; P<0.05]. Meanwhile, the nine former items in KD patients with coronary artery lesions (KD-CAL+) were lower than those without coronary artery lesions (KD-CAL-) [Promoter: (4.11±1.45)% vs (6.16±1.93)%; CNS1:(1.99±0.87)%vs (2.96±1.10)%;CNS2: (1.75±0.63)%vs (2.72±1.16)%;t=6.28, 3.24, 4.56, 3.69, 3.38, 4.40, 3.65, 3.00, 3.51; P<0.05]. No significant difference of H3K4me3 associated with CNS3 and H3K27me3 were found among the groups (t=1.03, 0.91, 1.48 and 0.79, 0.82, 1.53; P>0.05). ② Binding levels of SMYD3 and MLL5 with Foxp3 gene in CD4+T cells were down-regulated significantly during acute KD (t=6.63, 6.15; P<0.05), and restored to some extent after IVIG treatment (t=5.36, 4.56; P<0.05). Positive correlations between binding levels of SMYD3 and MLL5 and expression level of Foxp3 mRNA were detected in patients with acute KD (r=0.62、0.45, P<0.05). Furthermore, Binding levels of SMYD3 and MLL5 with Foxp3 gene in KD-CAL+group were lower than those in KD-CAL- group (t=4.11, 4.31; P<0.05). ③ Compared with healthy controls, plasma concentration of TGF-β and RA, and expressions of TGF-βRⅡ, TGF-βRⅠ, pSmad3 and RARα were down-regulated during acute KD (t=11.54, 12.81, 7.43, 16.10, 8.25, 12.06; P<0.05), and elevated remarkably after IVIG treatment (t=8.40, 6.24, 5.94, 11.78, 6.27, 8.30; P<0.05). Simultaneously, all the items aforementioned in KD-CAL+ group were found to be lower than those in KD-CAL-group (t=3.58, 3.30, 3.82, 5.27, 4.71, 3.78; P<0.05). Conclusion Hypomethylation of H3K4me3 associated with Foxp3 gene caused by insufficient binding levels of SMYD3/MLL5 may be involved with immune dysfunction in Kawasaki disease.