系统性红斑狼疮患者CD4^(+)T细胞碱基切除修复蛋白水平  

Levels of base excision repair proteins in CD4^(+)T cells in patients with systemic lupus erythematosus

作　　者：周星雨 武潇琪 邓敏 邱月棨 周胜男 李亚萍[1] ZHOU Xingyu;WU Xiaoqi;DENG Min;QIU Yueqi;ZHOU Shengnan;LI Yaping(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)

机构地区：[1]中南大学湘雅二医院皮肤科,湖南省医学表观基因组学湖南省重点实验室,长沙410011 [2]南华大学长沙市中心医院皮肤科,长沙410000

出　　处：《中南大学学报（医学版）》2022年第12期1655-1662,共8页Journal of Central South University ：Medical Science

基　　金：supported by the National Natural Science Foundation of China(81472881).

摘　　要：目的:系统性红斑狼疮(systemic lupus erythematosus,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SLE的发病机制,生长停滞和DNA损伤诱导型45α(Gadd45a)参与DNA的去甲基化过程。Gadd45a是一种DNA修复相关蛋白,因此,本研究旨在分析参与碱基切除修复(base excision repair,BER)过程的一些蛋白质,包括活化诱导胞嘧啶脱氨基化酶(activation-induced cytidine deaminase,AID)、胸腺嘧啶DNA糖基化酶(thymine DNA glycosylase,TDG)和甲基CpG结合蛋白4(methyl-CpG-binding domain protein 4,MBD4)在SLE患者CD4^(+)T细胞中的表达,并分析这些BER蛋白与SLE活动之间的相关性。方法:2019年1月至2020年9月中南大学湘雅二医院收集12例SLE患者和12例健康体检者(对照组)。采用Ficoll-Hypaque密度梯度离心法分离外周血单个核细胞(peripheral blood mononuclear cells,PBMCs),CD4免疫磁珠分离外周血CD4^(+)T细胞。通过实时反转录聚合酶链反应(real-time RTPCR)和蛋白质印迹法检测AID、TDG和MBD4信使RNA(mRNA)和蛋白质的表达水平。结果:与对照组相比,SLE患者CD4^(+)T细胞中AID mRNA和蛋白质表达升高(P=0.003,P=0.022)。SLE患者的CD4^(+)T细胞中TDG蛋白表达升高(P=0.017),MBD4蛋白质表达降低(P<0.001)。两组之间TDG和MBD4 mRNA表达水平没有明显差异(均P>0.05)。AID mRNA和蛋白水平及TDG蛋白水平与系统性红斑狼疮疾病活动度(SLE disease activity index,SLEDAI)呈正相关,MBD4 mRNA和蛋白水平与SLEDAI呈负相关。结论:SLE患者CD4^(+)T细胞中AID和TDG表达增加,MBD4表达降低,它们可能参与了SLE的发病机制。Objective: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.Conclusion:In SLE CD4^(+)T cells,the increased expressions of AID and TDG and the decreased MBD4 expression may participate in SLE pathogenic mechanism.

关 键 词：碱基切除修复 DNA低甲基化 系统性红斑狼疮 

分 类 号：R593.241[医药卫生—内科学]