Ultraviolet B inhibition of DNMT1 activity via AhR activation dependent SIRT1 suppression in CD4+T cells from systemic lupus erythematosus patients
Ultraviolet B inhibition of DNMT1 activity via AhR activation dependent SIRT1 suppression in CD4+T cells from systemic lupus erythematosus patients
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UltravioletB 通过 AhR 激活依赖性 SIRT1 抑制系统性红斑狼疮患者 CD4 T 细胞中的 DNMT1 活性
DOI：
10.1016/j.jdermsci.2017.03.006
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发表时间：
2017-06-01
影响因子：
4.6
通讯作者：
Shi, Weimin
中科院分区：
文献类型：
--
作者：
Wu, Zhouwei;Mei, Xingyu;Shi, Weimin
背景：之前的研究报道，紫外线 B (UVB) 会抑制系统性红斑狼疮 (SLE) 患者 CD4+ T 细胞中 DNA 甲基转移酶 (DNMT1) 的活性。沉默交配型信息调节 2 同源物 1 (SIRT1) 是一种 III 类组蛋白脱乙酰酶 (HDAC)，据报道在不同自身免疫性疾病的发病机制中发挥作用，并可以调节 DNMT1 活性。此外，据报道，芳烃受体 (AhR) 将 UVB 与 SLE 联系起来。然而，UVB 抑制狼疮 CD4+ T 细胞中 DNMT1 活性的确切机制仍不清楚。 目的：阐明 UVB 抑制狼疮 CD4+ T 细胞中 DNMT1 活性的确切机制。 方法：纳入 22 名新诊断的活动性 SLE 患者和 30 名健康对照者。分离、培养和处理CD4+T细胞。采用 DNMT1 活性测定、定量实时 PCR (qRT-PCR)、Western blotting、使用小干扰 RNA 的 RNA 干扰和染色质免疫沉淀 (ChIP) 测定。结果：在 si-SIRT1 转染的 CD4+ T 细胞中，DNMT1 活性受到抑制，而已建立的 SIRT1 激活剂 SRT1720 则增加了 DNMT1 活性。此外，狼疮 CD4+ T 细胞中 SIRT1 的 mRNA 和蛋白表达受到 UVB 暴露的抑制。在 si-control 转染的狼疮 CD4+ T 细胞中，SRT1720 逆转了 UVB 抑制的 DNMT1 活性，但在 si-SIRT1 转染的狼疮 CD4+ T 细胞中则不然。此外，VAF347 激活 AhR 降低了 SIRT1 的 mRNA 和蛋白表达。在正常 CD4+ T 细胞中使用针对 AhR 的抗体进行 ChIP，显示 SIRT1 启动子翻译起始位点上游约 1.6 kb 处的信号强 16 倍。最后，UVB可以激活AhR并抑制SIRT1的mRNA和蛋白表达。 AhR 敲除消除了对狼疮 CD4+ T 细胞中 UVB 介导的 SIRT1 mRNA 和蛋白表达以及 DNMT1 活性的抑制。结论：UVB 通过激活 AhR 抑制 SIRT1 表达，从而抑制 SLE 患者 CD4+ T 细胞中的 DNMT1 活性。 (C) 2017 年日本皮肤病研究学会。由爱思唯尔爱尔兰有限公司出版。保留所有权利。
Background: Previous studies have reported that ultraviolet B (UVB) inhibits DNA methyltransferasel (DNMT1) activity in CD4+ T cells from systemic lupus erythematosus (SLE) patients. Silent mating type information regulation 2 homolog 1 (SIRT1) is a type of Class III histone deacetylases (HDACs), and has been reported to play roles in the pathogenesis of different autoimmune diseases and can modulate DNMT1 activity. Moreover, aryl hydrocarbon receptor (AhR) has been reported to link UVB with SLE. However, the exact mechanisms by which DNMT1 activity is inhibited by UVB in lupus CD4+ T cells remain largely unknown.Objective: To elucidate the exact mechanisms by which DNMT1 activity is inhibited by UVB in lupus CD4+ T cells.Methods: Twenty-two newly diagnosed active SLE patients and 30 healthy controls were enrolled in the study. CD4+ T cells were isolated, cultured and treated. DNMT1 activity assay, quantitative real-time PCR (qRT-PCR), Western blotting, RNA interference using small interfering RNA and Chromatin Immunoprecipitation (ChIP) assay were employed.Results: DNMT1 activity was inhibited in si-SIRT1-transfected CD4+ T cells, and increased by the established SIRT1 activator, SRT1720. Moreover, the mRNA and protein expression of SIRT1 were suppressed by UVB exposure in lupus CD4+ T cells. UVB-inhibited DNMT1 activity was reversed by SRT1720 in si-control-transfected lupus CD4+ T cells, but not in si-SIRT1-transfected lupus CD4 + T cells. Furthermore, AhR activation by VAF347 reduced the mRNA and protein expression of SIRT1. ChIP using an antibody against AhR in normal CD4+ T cells revealed a 16-fold stronger signal at the site about 1.6 kb upstream from the translation start site of the SIRT1 promoter. Finally, UVB could activate AhR and inhibit the mRNA and protein expression of SIRT1. AhR knockdown abrogated the inhibition of UVB-mediated SIRT1 mRNA and protein expression and DNMT1 activity in lupus CD4+ T cells.Conclusion: UVB suppressed SIRT1 expression via activating AhR, and subsequently inhibited DNMT1 activity in CD4+ T cells from SLE patients. (C) 2017 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.