c-Myc、mTOR、HIF-1α基因启动子区域DNA甲基化与类风湿关节炎的相关性

Correlation of the promoter DNA methylation of c-Myc,mTOR,and HIF-1α genesin and rheumatoid arthritis

目的探讨基因(c-Myc、mTOR、HIF-1α)启动子区甲基化在类风湿关节炎(rheuma-toid arthritis,RA)发病中的作用。方法采集45例RA患者和45例健康对照者的外周血,通过焦磷酸测序技术检测c-Myc,mTOR与HIF-1α基因的甲基化水平。SPSS 20. 0进行统计学分析,并用Medcalc软件进行受试者工作特征曲线(ROC曲线)分析。双侧P值<0. 05认为具有统计学差异。结果 HIF-1α位点1 (position 1,pos1)和c-Myc (pos 2、3、4、5、6)甲基化水平RA组与健康对照组比较均具有统计学差异(P <0. 05),经过Bonferroni校正后,c-Myc (pos 5、6)位点甲基化水平两组仍具有统计学差异(经Bonferroni校正后的P'值分别为0. 028和0. 042,P'值<0. 05)。基因c-Myc (pos 5、6)位点在RA组与健康对照组的甲基化率分别为pos 5:9. 2%(8. 1%,10. 2%),10. 0%(9. 2%,10. 9%),经Bonferroni校正后P'=0. 028; pos 6:7. 5%(6. 4%,8. 2%),8. 3%(7. 5%,9. 0%),经Bonferroni校正后P'=0. 042。ROC曲线显示,c-Myc (pos 5、6)对诊断RA准确性较低(ROC曲线下面积:0. 5～0. 7,P <0. 05),当c-Myc pos 5甲基化率≤9. 48%时,灵敏性(SE)和特异性(SP)值最大(SE为0. 69,SP为0. 67)。血红蛋白(hemoglobin,HB)在c-Myc (pos 2、4、6)位点上具有统计学差异(P<0. 05),其中基因c-Myc各位点的甲基化率与HB的相关系数分别为(pos 2:r=0. 306,P=0. 041;pos 4:r=0. 299,P=0. 046; pos 6:r=0. 334,P=0. 025)。结论结合基因功能分析,c-Myc (pos 5、6)低甲基化水平可能增加类风湿关节炎的发病风险,c-Myc (pos 2、4、6)可能通过调控辅助性T细胞(Thelper cell 17,Th17)/调节性T细胞(regulatory cell,Treg)平衡参与RA伴慢性病性贫血(anemia of chro-nic disease,ACD)的发病过程。

Objective To explore whether promoter DNA methylation of c-Myc, mTOR, and HIF-1α genes contributes to the risk of rheumatoid arthritis(RA). Methods Forty-five patients diagnosed with RA and another forty-five healthy controls were allocated in Ningbo No. 2 Hospital from May 2017 to October 2017. The methylation levels of c-Myc, mTOR, and HIF-1α genes in peripheral blood were measured by pyrophosphate sequencing technology. All analyses were conducted with SPSS Version 20 (IBM Corp, Armonk, NY, USA) at a significance level of 0.05. In the meantime, Receiver Operating Characteristic (ROC) curves were analyzed by Medcalc software. Results The levels of methylation of HIF-1α pos 1( position1, pos1) and c-Myc (pos 2, 3, 4, 5, 6) were statistically significant ( P <0.05). After Bonferroni correction, the levels of methylation of c-Myc (pos 5, 6) were still significantly lower in RA patients (the P values were 0.028 and 0.042, respectively, P ′<0.05). Based on the functional gene analysis, the lower methylation levels of c-Myc (pos 5, 6) might increase the risk of RA. The levels of methylation of gene c-Myc between RA and control group were pos 5:9.2%(8.1%,10.2%) vs. 10.0%(9.2%,10.9%), P ′=0.028;pos 6:7.5%(6.4%,8.2%) vs. 8.3%(7.5%,9.0%), P ′=0.042. ROC curve showed that methylation of c-Myc (pos 5, 6) sites did not predict the diagnosis of RA accurately (area under ROC curve: 0.5-0.7, P <0.05). When the level of methylation gene c-Myc pos 5 was less than 9.48%, the sensitivity (SE) and specificity (SP) reached a maximum (SE=0.69, SP=0.67). The levels of methylation of c-Myc(pos 2, 4, 6) and hemoglobin were statistically significant ( P <0.05). The correlation coefficients between the levels of methylation of gene c-Myc and hemoglobin were(pos 2: r =0.306, P =0.041;pos 4: r =0.299, P =0.046;pos 6: r =0.334, P =0.025). Conclusion Based on the functional gene analysis results, the lower methylation levels of c-Myc(pos 5, 6) might increase the risk of RA. c-Myc (pos 2, 4, 6) might be involved in the pathogenesis of RA with anemia of chronic disease by regulating the balance of Th17 cells/regulatory T-cells.