系统性红斑狼疮患者 CD4 T 细胞中碱基切除修复蛋白的水平。
Levels of base excision repair proteins in CD4 T cells in patients with systemic lupus erythematosus.
机构信息
Department of Dermatology, Hunan Key Laboratory of Medical Epigenomics; Second Xiangya Hospital, Central South University, Changsha 410011.
Department of Dermatology, Changsha Central Hospital, University of South China, Changsha 410000, China.
出版信息
Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2022 Dec 28;47(12):1655-1662. doi: 10.11817/j.issn.1672-7347.2022.210485.
OBJECTIVES
Systemic lupus erythematosus (SLE) is a multi-systemic disease with the unknown pathogenic mechanism. DNA demethylation is involved in SLE pathogenesis. Growth arrest and DNA damage inducible 45 alpha (Gadd45a) takes part in the process of DNA demethylation. Gadd45a is a DNA repair-related protein. This study aims to investigate the expressions of some proteins [including activation-induced cytidine deaminase (AID), thymine DNA glycosylase (TDG), and methyl-CpG-binding domain protein 4 (MBD4)] involving in base excision repair (BER) process in CD4 T cells in patients with SLE, and to analyze the correlations between the above BER proteins and lupus disease.
METHODS
From January 2019 to September 2020, 12 SLE patients and 12 healthy controls were recruited from Second Xiangya Hospital of Central South University. Peripheral blood mononuclear cells (PBMCs) were separated by Ficoll-Hypaque density gradient centrifugation and then CD4+ T cells were isolated via positive selection using Miltenyi beads. We measured the messenger RNA (mRNA) and protein expressions of AID, TDG, and MBD4 by real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting, respectively.
RESULTS
In contrast to controls, in SLE CD4+ T cells, the mRNA and protein expressions of AID were elevated (P=0.003, P=0.022, respectively); TDG protein expression was increased (P=0.017); and MBD4 protein level was reduced (P<0.001). No visible distinctions was found in the mRNA expressions of either TDG or MBD4 between the 2 groups (both P>0.05). The mRNA and protein expressions of AID and the protein levels of TDG were positively correlated with SLE disease activity index (SLEDAI). And the mRNA and protein expressions of MBD4 were negatively correlated with SLEDAI.
CONCLUSIONS
In SLE CD4+ T cells, the increased expressions of AID and TDG and the decreased MBD4 expression may participate in SLE pathogenic mechanism.
目的
系统性红斑狼疮（SLE）是一种多系统疾病，其发病机制尚不清楚。DNA 去甲基化参与了 SLE 的发病机制。生长停滞和 DNA 损伤诱导 45 阿尔法（Gadd45a）参与了 DNA 去甲基化过程。Gadd45a 是一种与 DNA 修复相关的蛋白质。本研究旨在探讨 SLE 患者 CD4+T 细胞中参与碱基切除修复（BER）过程的一些蛋白质[包括激活诱导胞嘧啶脱氨酶（AID）、胸腺嘧啶 DNA 糖基化酶（TDG）和甲基-CpG 结合域蛋白 4（MBD4）]的表达，并分析上述 BER 蛋白与狼疮疾病的相关性。
方法
本研究于 2019 年 1 月至 2020 年 9 月期间，选取 12 例 SLE 患者和 12 名健康对照者，均来自中南大学湘雅二医院。采用 Ficoll-Hypaque 密度梯度离心法分离外周血单个核细胞（PBMCs），然后通过 Miltenyi 珠阳性选择法分离 CD4+T 细胞。采用实时逆转录聚合酶链反应（RT-PCR）和 Western 印迹法分别检测 AID、TDG 和 MBD4 的信使 RNA（mRNA）和蛋白表达。
结果
与对照组相比，SLE CD4+T 细胞中 AID 的 mRNA 和蛋白表达升高（P=0.003，P=0.022）；TDG 蛋白表达增加（P=0.017）；MBD4 蛋白水平降低（P<0.001）。两组间 TDG 或 MBD4 的 mRNA 表达无明显差异（均 P>0.05）。AID 的 mRNA 和蛋白表达以及 TDG 蛋白水平与 SLE 疾病活动指数（SLEDAI）呈正相关。而 MBD4 的 mRNA 和蛋白表达与 SLEDAI 呈负相关。
结论
在 SLE CD4+T 细胞中，AID 和 TDG 的表达增加，MBD4 表达减少，可能参与了 SLE 的发病机制。
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