miR-155在溃疡性结肠炎患者直肠黏膜和外周血单个核细胞中的表达及意义

Expressions and significance of miR-155 in rectal mucosa and peripheral blood mononuclear cells in patients with ulcerative colitis

目的通过检测微小核糖核酸-155(microRNA-155,miR-155)在溃疡性结肠炎(UC)患者直肠黏膜和外周血单个核细胞(PBMC)中的表达,探讨miR-155在UC中的作用及意义。方法选择2016年3月至9月诊治的25例活动期UC患者(UC组)及同期15例结肠息肉患者(对照组),肠镜下观察患者肠道黏膜炎症表现,并行直肠黏膜活检(其中结肠息肉患者取其正常直肠黏膜)作病理学检查。实时荧光定量PCR(qRT-PCR)检测直肠黏膜中miR-155、白介素(IL)-17 mRNA、IL-6 mRNA及PBMC中miR-155的表达,直肠黏膜中miR-155与IL-17 mRNA、IL-6mRNA表达的关系采用Pearson相关性分析;免疫组织化学方法检测直肠黏膜中IL-17、IL-6蛋白的表达情况并进行表达评分,分析直肠黏膜及PBMC中miR-155的水平与患者临床特征的关系。结果 25例活动期UC患者,其直肠黏膜中miR-155相对表达量明显高于对照组(13.57±2.78 vs 1.02±0.05,P<0.01);PBMC中miR-155相对表达量亦明显高于对照组(23.68±4.23 vs 0.92±0.04,P<0.01);直肠黏膜中IL-17 mRNA(7.79±1.45 vs 1.20±0.05)及IL-6 mRNA(6.10±1.17 vs 1.02±0.03)相对表达量均高于对照组(P均<0.05)。相关性分析显示,直肠黏膜中miR-155与IL-17 mRNA、IL-6 mRNA的表达呈正相关(r=0.934,P<0.01;r=0.909,P<0.01)。活动期UC患者直肠黏膜免疫组化IL-17蛋白表达评分[(3.44±0.25)分vs(1.20±0.18)分]及IL-6蛋白[(3.12±0.28)分vs(0.80±0.17)分]高于对照组(P均<0.01)。相关分析显示,miR-155在活动期UC患者直肠黏膜及PBMC中的相对表达量,与患者疾病活动指数呈正相关(r=0.804,P<0.01;r=0.813,P<0.01);与患者年龄(r=0.067,P>0.05;r=0.006,P>0.05)及性别无关(r=0.151,P>0.05;r=0.202,P>0.05)。结论 miR-155可能参与了UC的发病,其机制可能与促进辅助性T细胞(Th)17分泌的致炎因子IL-17和IL-6的表达有关,可为UC患者病情活动性及严重程度的评价提供参考。

Objective To investigate the expressions of microRNA -155 （miR-155） in rectal mucosa and peripheral blood mononuclear cells （PBMCs） in patients with ulcerative colitis（UC） to explore the role and significance of miR-155 in UC. Methods Twenty-five UC patients in active stage diagnosed and treated from March to September 2016 were selected as UC group,and 15 patients with colon polyps at same time were selected as control group. The inflammatory manifestation of intestinal mucosa was observed under enteroscopy, and then rectal mucosa biopsy was performed for pathological examina- tion. Real time fluorescent quantitative polymerase chain reaction （qRT-PCR） was used to detect the expressions of miR-155 ,interleukin （IL） -17 mRNA,IL-6 mRNA in rectal mucosa and the expression of miR-155 in PBMCs. The rela-tionship between the expression of miR-155 and the expressions of IL-17 mRNA, IL-6 mRNA in rectal mucosa was analyzed by Pearson＇s correlation analysis. The immunohistochemistry method was used to detect the expressions of IL-17 and IL-6 proteins in rectal mucosa, and the expression score was determined. The relationship between the expression levels of miR-155 in rectal mucosa and in PBMCs and the clinical features of UC patients was analyzed. Results The relative ex- pression levels of miR-155 in rectal mucosa （ 13.57 ± 2.78 vs 1.02 ± 0.05, P 〈 0.01 ） and in PBMCs （23.68 ± 4.23 vs 0. 92 ±0.04 ,P 〈0.01 ） were significantly higher in UC group than those in control group. The relative expression levels of IL-17 mRNA（7.79 ± 1. 45 vs 1.20 ± 0.05） and IL-6 mRNA （6.10 -± 1.17 vs 1.02 ± 0.03） in rectal mucosa of UC group were all significantly higher than those in control group （all P 〈 0.05 ）. Correlation analysis showed that miR-155 expres- sion in rectal mucosa was positively correlated with the expressions of IL-17 mRNA and IL-6 mRNA in rectal mucosa （ r = 0. 934, P 〈 0. 01 ; r = 0. 909,P 〈 0.01 ）. Immunohistochemistry showed that the expression scores of IL-17 protein （ 3.44 ± 0. 25 vs 1.20 ± 0.18）and IL-6 protein （3.12 ± 0.28 vs 0. 80 ± 0.17 ）in UC group were significantly higher than those in control group（all P 〈 0.01 ）. Correlation analysis showed that the relative expression levels of miR-155 in rectal mucosa and PBMCs in UC group were positively correlated with severity of the disease （Mayo score） （r = 0. 804, P 〈 0. 01 ;r = 0. 813,P 〈 0. 01 ）, but were not correlated with age （ r = 0. 067, P 〉 0. 05, r = 0. 006, P 〉 0.05 ） and gender （ r = 0. 151, P 〉 0. 05 ;r = 0. 202 ,P 〉 0.05 ）. Conclusions MiR-155 may be involved in the pathogenesis of UC, and the mechanism may be related to its promotion effect on the expression of proinflammatory cytokines IL-17 and IL-6 secreted by helper T cell 17 （Th17）. It can provide reference for the evaluation of disease activity and severity in patients with UC.