Objective: To investigate the mechanism of immunomodulatory effects of umbilical cord mesenchymal stem cells (UC-MSCs) modified by miR-125b-5p on systemic lupus erythematosus (SLE).
Methods: The expression level of miR-125b-5p was detected by real-time fluorescence quantitative PCR in UC-MSCs and peripheral blood mononuclear cells (PBMCs) from SLE patients and health checkers. Annexin V-FITC/PI apoptosis detection kit was used to detect the effect of miR-125b-5p on apoptosis of UC-MSCs. MRL/lpr mice in each group were injected with UC-MSCs via tail vein, and T-lymphocyte subsets in the spleen of the MRL/lpr mice were detected by flow cytometry after 5 weeks. The expression levels of interleukin (IL)-4 and IL-17A in serum of MRL/lpr mice were detected by ELISA. Hematoxylin-eosin staining was used to observe the pathological manifestations of the lungs and kidneys of the MRL/lpr mice.
Results: miR-125b-5p was significantly down-regulated in PBMCs of SLE patients compared with healthy controls (P < 0.01). Compared with the UC-MSCs group, the expression of miR- 125b-5p in UC-MSCs modified by miR-125b-5p group was increased (P < 0.01). The survival rate of UC-MSCs was significantly increased by miR-125b-5p (P < 0.01). Compared with the untreated group of MRL/lpr mice, the expression level of IL-4 in serum was increased (P < 0.05); the expression level of IL-17A was decreased (P < 0.05); the proportion of Th17 cells in the spleen of MRL/lpr mice was decreased (P < 0.05); the inflammatory cells infiltration and micro-thrombosis of lungs and kidneys of MRL/lpr mice were significantly reduced in the UC-MSCs modified by miR-125b-5p treatment group.
Conclusion: UC-MSCs modified by miR-125b-5p have immunomodulatory effects on systemic lupus erythematosus.
目的: 研究miR-125b-5p修饰脐带间充质干细胞(umbilical cord mesenchymal stem cells，UC-MSCs)对系统性红斑狼疮(systemic lupus erythematosus，SLE)的免疫调控作用机制。
方法: 实时荧光定量PCR检测miR-125b-5p在UC-MSCs和SLE患者、健康体检者外周血单个核细胞中的表达水平；Annexin V-FITC/PI凋亡检测试剂盒检测miR-125b-5p对UC-MSCs的凋亡影响；每周对MRL/lpr小鼠进行尾静脉注射UC-MSCs，5周后流式细胞术检测各组小鼠脾细胞T淋巴细胞亚群分化情况；ELISA法检测各组MRL/lpr小鼠血清中白细胞介素(interleukin，IL)-4和IL-17A表达水平；苏木精-伊红染色法观察MRL/lpr小鼠肺和肾组织病理变化。
结果: 与健康对照组相比，SLE患者外周血单个核细胞中miR-125b-5p的表达水平显著下调(P < 0.01)；与UC-MSCs相比，miR-125b-5p转染UC-MSCs组miR-125b-5p的表达水平显著上调(P < 0.01)。miR-125b-5p转染UC-MSCs 48 h可显著提高细胞存活率(P < 0.01)；与未处理的MRL/lpr小鼠组相比，miR-125b-5p修饰UC-MSCs对MRL/lpr小鼠脾脏Th17细胞分化具有明显的下调作用(P < 0.05)，且在小鼠血清中IL-4表达水平明显升高(P < 0.05)，IL-17A表达水平明显减低(P < 0.05)。经miR-125b-5p修饰的UC-MSCs治疗后，MRL/lpr小鼠肺和肾组织内炎性细胞浸润和微血栓减少。
结论: miR-125b-5p修饰UC-MSCs对SLE具有免疫调控作用。
Keywords: Gene modification; Immunomo-dulation; Mesenchymal stem cells; Systemic lupus erythematosus; Umbilical cord.