Demethylation of ITGAL (CD11a) regulatory sequences in systemic lupus erythematosus
Demethylation of ITGAL (CD11a) regulatory sequences in systemic lupus erythematosus
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DOI：
10.1002/art.10234
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发表时间：
2002-05-01
影响因子：
--
通讯作者：
Richardson, B
中科院分区：
文献类型：
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作者：
Lu, QJ;Kaplan, M;Richardson, B
客观的。 T 细胞 DNA 甲基化的抑制会导致体外自身反应性和体内狼疮样疾病，表明 T 细胞 DNA 低甲基化可能导致自身免疫。低甲基化效应部分归因于淋巴细胞功能相关抗原 1 (LFA-1) (CD11a/CD18) 的过度表达。重要的是，来自活动性狼疮患者的 T 细胞具有低甲基化 DNA，并在自身反应亚群上过度表达 LFA-1，这表明相同的机制可能导致人类狼疮。本研究调查了影响体外和人类狼疮中 LFA-1 表达的甲基化变化的性质。方法。使用亚硫酸氢盐测序来确定狼疮患者和健康受试者的 T 细胞以及用 DNA 甲基化抑制剂处理的 T 细胞中 ITGAL 启动子和侧翼区域的甲基化状态。报告构建体中启动子序列的“补丁”甲基化用于确定甲基化变化的功能意义。结果。在活动性狼疮患者的 T 细胞以及用 5-氮杂胞苷和普鲁卡因酰胺处理的 T 细胞中，发现 ITGAL 启动子侧翼特定序列的低甲基化。该区域的补丁甲基化抑制了 ITGAL 启动子功能。结论。 DNA 甲基化变化发生在调节狼疮 T 细胞和低甲基化模型中 LFA-1 表达的特定序列中，表明特定基因的甲基化改变可能在狼疮的发病机制中发挥作用。
Objective. Inhibition of T cell DNA methylation causes autoreactivity in vitro and a lupus-like disease in vivo, suggesting that T cell DNA hypomethylation may contribute to autoimmunity. The hypomethylation effects are due, in part, to overexpression of lymphocyte function-associated antigen 1 (LFA-1) (CD11a/CD18). Importantly, T cells from patients with active lupus have hypomethylated DNA and overexpress LFA-1 on an autoreactive subset, suggesting that the same mechanism could contribute to human lupus. The present study investigated the nature of the methylation change that affects LFA-1 expression in vitro and in human lupus.Methods. Bisulfite sequencing was used to determine the methylation status of the ITGAL promoter and flanking regions in T cells from lupus patients and healthy subjects, and in T cells treated with DNA methylation inhibitors. "Patch" methylation of promoter sequences in reporter constructs was used to determine the functional significance of the methylation changes.Results. Hypomethylation of specific sequences flanking the ITGAL promoter was seen in T cells from patients with active lupus and in T cells treated with 5-azacytidine and procainamide. Patch methylation of this region suppressed ITGAL promoter function.Conclusion. DNA methylation changes occur in specific sequences that regulate LFA-1 expression in lupus T cells and in the hypomethylation model, indicating that altered methylation of specific genes may play a role in the pathogenesis of lupus.