四型肽精氨酸转亚胺基酶功能基因多态性及其表达与类风湿关节炎相关性研究

Association of peptidylarginine deiminase Ⅳ gene polymorphisms and its expression with rheumatoid arthritis in Chinese patients

目的探讨四型肽精氨酸转亚胺基酶（PADI4）功能基因多态性及其表达与类风湿关节炎（RA）的相关性。方法采用实时荧光定量反转录-聚合酶链反应（RT—PCR）方法检测70例RA患者、81名健康对照者外周血单个核细胞（PBMC）中PADI4基因的表达水平，采用DNA测序和TA载体克隆方法分析PADI4基因外显子内第89、90、92、104位点单核苷酸多态性（SNPs）。结果4个SNPs中除了PADI4_92位点外，携带PADI4少见等位基因者发生RA的易感性显著高于携带常见等位基因者；在所研究对象中分别由4个位点上的常见等位基因（ACCC）和少见等位基因（GTGT）组成的功能基因型为主要基因型。与ACCC型比较，携带GTGT型者发生RA危险性显著增高（P〈0．01）。RA组PADI4基因表达水平显著高于正常对照组（P〈0．05），并且在RA组和对照组中携带PADI4少见等位基因者PADI4的表达水平显著高于携带常见等位基因者。结论PADI4功能基因多态性及其基因表达与中国人RA易感性相关，PADI4功能基因多态性影响基因表达。

Objective The current study is aimed to investigate the association of single nucleotide polymorphisms and gene expression in peptidylarginine deiminase IV （PADI4） with rheumatoid arthritis （RA）. Methods The gene expression of PADI4 was examined using real-time quantitative reverse transcription- polymerase chain reaction （RT-PCR） in 70 patients with RA and 81 healthy controls. Four exonic SNPs of the PADI4 gene （PADI4_89, _90, _92, _104） were genotyped using DNA sequencing and TA cloning. Results The distribution of PADI4_89, _90, _104 SNPs in RA was different from that of healthy controls. The increased RA susceptibility was significantly associated with minor alleles. When haplotypes were construc -ted with 4 SNPs, two major haplotypes, ACCC and GTGT were found in all samples, and GTGT haplo -type （carrying only the minor alleles） was significantly associated with increased RA susceptibility （P〈0.01） in comparison with the reference haplotype ACCC. There was over expression of PADI4 in RA than controls （P〈0.05）. Genotypes carrying the minor alleles had higher expression level of PADI4 in RA and controls than those with the common alleles. Conclusion PADI4 SNPs and haplotypes are associated with RA susceptibility in Chinese. PADI4 is over-expressed in the blood of RA patients, and there is significant association between the haplotypes and expression level of the PADI4 gene.