微小RNA-126基因在CD4+T细胞介导小鼠自身免疫性肠炎中的作用

目的 研究微小RNA-126(microRNA-126,miR-126)基因敲减(knock down,KD)对CD4+T细胞介导的自身免疫性结肠炎模型的影响并探讨其意义.方法 常规利用DSS溶液喂养野生型(WT)和miR-126基因敲减(miR-126KD)小鼠,诱导急性自身免疫性结肠炎模型.HE染色观察小鼠结肠组织病理变化;FACS检测CD4+T细胞的比例变化及其表面活化分子CD62L、CD44的表达;MACS分选出WT和miR-126KD小鼠脾脏中CD4+ CD62L+T细胞,CFSE染色标记后,分别经尾静脉转输给WT小鼠,再诱导自身免疫性结肠炎模型;HE染色观察结肠组织病理变化;FACS检测CFSE阳性CD4+T细胞表面活化分子CD62L、CD44的表达变化.结果 与对照组相比,miR-126KD小鼠肠组织绒毛缺失不完整,黏膜上皮出现较大溃疡,炎性细胞浸润增加;FACS结果显示,miR-126KD组小鼠CD4+T细胞比例和总数显著上调(P＜0.01);且高表达CD44,低表达CD62L;过继转输实验结果显示,miR-126KD小鼠CD4+T细胞转输组结肠组织损伤加重;同时,CFSE+细胞高表达CD44,低表达CD62L.结论 miR-126基因敲减加重葡聚糖硫酸钠所致肠炎的病变程度.

Role of microRNA-126 in CD4+ T cell-mediated autoimmune colitis in mice

Objective To study the effect of microRNA-126 knockdown on CD4 + T cell-mediated autoimmune colitis in mice.Methods Wild-type mice and mice with microRNA-126 knockdown (miR-126KD) were fed with dextran sulfate sodium (DSS) solution for 7 d to induce acute autoimmune colitis.The pathological changes of the intestinal tissues were observed with HE staining,and the changes in CD4 + T cell percentage and expression levels of CD62L and CD44 molecules in CD4 + T cells were analyzed with fluorescence-activated cell sorting (FACS).CD4 + CD62L+ T cells purified from the spleen of miR-126 KD mice using magnetic activated cell sorting were stained with carboxyfluorescein diacetate,succinimidyl ester (CFSE) and adoptively transferred into the wild-type mice,which were then exposed to DSS in drinking water to induce autoimmune colitis.The intestinal pathologies and changes of CD62L and CD44 expression in CFSE-positive cells of the recipient mice were analyzed with FACS.Results Compared with the normal control mice,miR-126KD mice with DSS-induced acute autoimmune colitis presented with obvious losses of intestinal villi,extensive ulcers in the mucosal epithelium and obvious infiltration of inflammatory cells in the intestinal tissues.FACS results showed that the percentage and total number of CD4 + T cells were increased significantly in miR-126KD mice with a high expression of CD44 and a low expression of CD62L in CD4 + T cells (P ＜ 0.01).Adoptive transfer experiments showed that miR-126KD CD4+ T cell transfer aggravated intestinal tissue damage in wild-type mice with acute autoimmune colitis,and CFSE + cells from the wild-type mice showed an increased CD44 expression and a decreased CD62L expression.Conclusion miR-126 knockdown aggravates the pathological changes of CD4 +T cell-mediated inflammatory bowel disease in mice induced by DSS.