Rush University Medical Center, Chicago, Illinois.
Albert Szent-Györgyi Clinical Center, Szeged, Hungary.
Arthritis Rheumatol. 2019 Aug;71(8):1265-1275. doi: 10.1002/art.40877. Epub 2019 Jun 18.
Disease-associated, differentially hypermethylated regions have been reported in rheumatoid arthritis (RA), but no DNA methyltransferase inhibitors have been evaluated in either RA or any animal models of RA. The present study was conducted to evaluate the therapeutic potential of 5'-azacytidine (5'-azaC), a DNA methyltransferase inhibitor, and explore the cellular and gene regulatory networks involved in the context of autoimmune arthritis.
A disease-associated genome-wide DNA methylation profile was explored by methylated CpG island recovery assay-chromatin immunoprecipitation (ChIP) in arthritic B cells. Mice with proteoglycan-induced arthritis (PGIA) were treated with 5'-azaC. The effect of 5'-azaC on the pathogenesis of PGIA was explored by measuring serum IgM and IgG1 antibody levels using enzyme-linked immunosorbent assay, investigating the efficiency of class-switch recombination (CSR) and Aicda gene expression using real-time quantitative polymerase chain reaction, monitoring germinal center (GC) formation by immunohistochemistry, and determining alterations in B cell subpopulations by flow cytometry. The 5'-azaC-induced regulation of the Aicda gene was explored using RNA interference, ChIP, and luciferase assays.
We explored arthritis-associated hypermethylated regions in mouse B cells and demonstrated that DNA demethylation had a beneficial effect on autoimmune arthritis. The 5'-azaC-mediated demethylation of the epigenetically inactivated Ahr gene resulted in suppressed expression of the Aicda gene, reduced CSR, and compromised GC formation. Ultimately, this process led to diminished IgG1 antibody production and amelioration of autoimmune arthritis in mice.
DNA hypermethylation plays a leading role in the pathogenesis of autoimmune arthritis and its targeted inhibition has therapeutic potential in arthritis management.
在类风湿关节炎（RA）中已报道了与疾病相关的、差异超甲基化区域，但尚未在 RA 或任何 RA 动物模型中评估任何 DNA 甲基转移酶抑制剂。本研究旨在评估 5'-氮杂胞苷（5'-azaC），一种 DNA 甲基转移酶抑制剂的治疗潜力，并探索与自身免疫性关节炎相关的细胞和基因调控网络。
通过甲基化 CpG 岛回收分析 - 染色质免疫沉淀（ChIP）在关节炎 B 细胞中探索与疾病相关的全基因组 DNA 甲基化谱。用蛋白聚糖诱导性关节炎（PGIA）治疗 5'-azaC。通过酶联免疫吸附试验测量血清 IgM 和 IgG1 抗体水平，实时定量聚合酶链反应研究 5'-azaC 对 PGIA 发病机制的影响，探讨 CSR 和 Aicda 基因表达的效率，通过免疫组织化学监测生发中心（GC）的形成，并通过流式细胞术确定 B 细胞亚群的变化。使用 RNA 干扰、ChIP 和荧光素酶测定探索 5'-azaC 诱导的 Aicda 基因调节。
我们探索了小鼠 B 细胞中与关节炎相关的高甲基化区域，并证明 DNA 去甲基化对自身免疫性关节炎有有益的影响。5'-azaC 介导的 Ahr 基因表观遗传失活的去甲基化导致 Aicda 基因表达受到抑制，CSR 减少，GC 形成受损。最终，这一过程导致 IgG1 抗体产生减少，改善了小鼠的自身免疫性关节炎。
DNA 高甲基化在自身免疫性关节炎的发病机制中起主导作用，其靶向抑制在关节炎管理中具有治疗潜力。
