Chen Hongbo, Fan Junfen, Shou Qiyang, Zhang Lizong, Ma Hongzhen, Fan Yongsheng
Department of Nephrology, First Affiliated Hospital, Zhejiang Chinese Medicine University, Hangzhou, People's Republic of China.
Rheumatol Int. 2015 Aug;35(8):1335-42. doi: 10.1007/s00296-015-3266-5. Epub 2015 Apr 22.
Our aim was to investigate the relationship between the DNA methylation status of glucocorticoid receptor (GR) gene promoter and mRNA expression level of GRα gene of peripheral blood mononuclear cells (PBMCs) in patients with systemic lupus erythematosus (SLE). Fifteen newly emerging SLE patients and fifteen healthy controls were enrolled in this study. DNA and total RNA were extracted from the PBMCs of the SLE patients and healthy controls. The DNA methylation status of GR gene promoter 1 of PBMCs was detected through bisulfite-sequencing PCR. The mRNA expression of GRα, DNA methyltransferases (DNMT1, DNMT3a, DNMT3b) and growth arrest, and DNA damage-induced 45α (GADD45α) of PBMCs was detected using the quantitative real-time polymerase chain reaction method. The mRNA expression of GRα was significantly declined in SLE patients, and the mRNA expression of DNMT1 and GADD45α was significantly elevated in SLE patients. The global methylation status of PBMCs in SLE patients was obviously lower than healthy controls. There were 38, 25, 30, and 49 CpG islands in amplified fragment of GR promoter 1D, 1E, 1F, and 1H, respectively. The overall mean methylation status of the 152 CpG islands of the four promoters was significantly elevated in SLE patients. There was a negative correlation between hypermethylation of GR promoter and GRα mRNA expression in SLE patients. This study demonstrated that hypermethylation of GRα promoter may result in GRα gene low expression in PBMCs of patients with SLE. This study also found that the global methylation status of PBMCs in SLE patients was obviously lower than healthy controls, and it was related to the elevated GADD45α mRNA expression in SLE patients. These conclusions have to be certified by larger-scale clinical studies.
我们的目的是研究系统性红斑狼疮（SLE）患者外周血单个核细胞（PBMC）中糖皮质激素受体（GR）基因启动子的DNA甲基化状态与GRα基因mRNA表达水平之间的关系。本研究纳入了15例新确诊的SLE患者和15名健康对照。从SLE患者和健康对照的PBMC中提取DNA和总RNA。通过亚硫酸氢盐测序PCR检测PBMC中GR基因启动子1的DNA甲基化状态。采用定量实时聚合酶链反应法检测PBMC中GRα、DNA甲基转移酶（DNMT1、DNMT3a、DNMT3b）以及生长停滞和DNA损伤诱导蛋白45α（GADD45α）的mRNA表达。SLE患者中GRα的mRNA表达显著下降，而DNMT1和GADD45α的mRNA表达显著升高。SLE患者PBMC的整体甲基化状态明显低于健康对照。GR启动子1D、1E、1F和1H的扩增片段中分别有38、25、30和49个CpG岛。SLE患者中四个启动子的152个CpG岛的总体平均甲基化状态显著升高。SLE患者中GR启动子的高甲基化与GRα mRNA表达呈负相关。本研究表明，GRα启动子的高甲基化可能导致SLE患者PBMC中GRα基因低表达。本研究还发现，SLE患者PBMC的整体甲基化状态明显低于健康对照，且这与SLE患者中GADD45α mRNA表达升高有关。这些结论有待大规模临床研究证实。
