Aslani Saeed, Mahmoudi Mahdi, Garshasbi Masoud, Jamshidi Ahmad Reza, Karami Jafar, Nicknam Mohammad Hossein
Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Clin Rheumatol. 2016 Nov;35(11):2723-2731. doi: 10.1007/s10067-016-3403-x. Epub 2016 Sep 16.
Ankylosing spondylitis (AS) is an autoimmune disease with a chronic inflammatory arthritis. The critical role of methylation in the biology of immunocytes has increasingly been surveyed to discover disease etiology. DNA methyltransferase 1 (DNMT1) is an enzyme, which establishes and regulates patterns of methylated cytosine residues. The aim of the current investigation was to unveil if methylation circumstances of CpG sites in DNMT1 promoter could affect the mRNA expression level of this gene in peripheral blood mononuclear cells (PBMCs) from AS patients. PBMCs were isolated from whole blood of 40 AS patients and 40 healthy individuals. Total RNA and DNA contents of leukocytes were extracted. Afterward, quantitative analysis was carried out by real-time PCR using the SYBR Green PCR Master Mix. Finally, to determine the methylation level, PCR products of bisulfite-treated DNA from patients and controls were sequenced. Compared with healthy controls, expression level of DNMT1 in AS patients was significantly downregulated. Methylation of DNMT1 promoter was significantly higher in AS patients in comparison to controls. While a negative correlation between methylation and expression level of DNMT1 was observed in AS patients, both methylation and expression level of DNMT1 did not correlate with clinical manifestations. Considering the observation that decreased expression level of DNMT1 was associated with hypermethylation of DNMT1 promoter in PBMCs from AS patients, this survey suggests that dysregulation of DNMT1 expression through altered methylation level of other target genes would probably contribute to AS development.
强直性脊柱炎（AS）是一种伴有慢性炎症性关节炎的自身免疫性疾病。甲基化在免疫细胞生物学中的关键作用已越来越多地被研究以发现疾病病因。DNA甲基转移酶1（DNMT1）是一种建立和调节甲基化胞嘧啶残基模式的酶。本研究的目的是揭示DNMT1启动子中CpG位点的甲基化情况是否会影响AS患者外周血单个核细胞（PBMCs）中该基因的mRNA表达水平。从40例AS患者和40例健康个体的全血中分离出PBMCs。提取白细胞的总RNA和DNA含量。随后，使用SYBR Green PCR Master Mix通过实时PCR进行定量分析。最后，为了确定甲基化水平，对患者和对照经亚硫酸氢盐处理的DNA的PCR产物进行测序。与健康对照相比，AS患者中DNMT1的表达水平显著下调。与对照相比，AS患者中DNMT1启动子的甲基化显著更高。虽然在AS患者中观察到DNMT1的甲基化与表达水平呈负相关，但DNMT1的甲基化和表达水平均与临床表现无关。鉴于观察到AS患者PBMCs中DNMT1表达水平降低与DNMT1启动子的高甲基化有关，本研究表明通过改变其他靶基因的甲基化水平导致的DNMT1表达失调可能有助于AS的发展。
