长链非编码RNA母系表达基因3调控miR-34a对糖尿病视网膜病变Müller细胞活化及炎症因子分泌的影响

Effect of lncRNA MEG3 regulating miR-34a on the activation of Müller cells and the secretion of inflammatory cytokines in diabetic retinopathy

目的探讨母系表达基因3(maternally expressed gene 3,MEG3)对糖尿病视网膜病变(DR)Müller细胞的活化及炎症因子分泌的影响及机制。方法高脂饮食联合链脲佐菌素腹腔注射构建小鼠DR体内模型。高糖刺激人视网膜Müller细胞株MIO-M1构建DR体外模型。免疫荧光化学染色及Western blot检测小鼠视网膜及Müller细胞中胶质纤维酸性蛋白(GFAP)的表达。Western blot及酶联免疫吸附实验(ELISA)检测小鼠视网膜及细胞培养基上清中血管内皮生长因子(VEGF)蛋白的表达。ELISA检测小鼠视网膜及细胞培养基上清中IL-1β蛋白的表达。分别或同时向Müller细胞中转染pcDNA-MEG3及miR-34a mimic对其表达进行干预。qRT-PCR检测MEG3 mRNA及miR-34a表达。结果与正常对照组小鼠比较,DR组小鼠视网膜中GFAP、VEGF及IL-1β蛋白表达均增多(均为P<0.05),MEG3 mRNA表达降低(P<0.01)。与对照组比较,高糖组Müller细胞中MEG3 mRNA表达降低(P<0.01),而GFAP、VEGF及IL-1β蛋白表达均升高(均为P<0.05)。与高糖组比较,高糖+pcDNA-MEG3组中GFAP、VEGF及IL-1β蛋白表达均降低(均为P<0.05)。与正常对照组比较,DR组小鼠视网膜及高糖刺激的Müller细胞中miR-34a表达均升高(均为P<0.05)。与pcDNA组比较,pcDNA-MEG3组中miR-34a表达减少(P<0.01)。与pcDNA+NC mimic组比较,pcDNA+miR-34a mimic组中GFAP、VEGF及IL-1β蛋白表达均升高(均为P<0.05),而pcDNA-MEG3+NC mimic组中GFAP、VEGF及IL-1β蛋白表达均减少(均为P<0.05)。与pcDNA-MEG3+miR-34a mimic组比较,GFAP、VEGF及IL-1β蛋白表达水平均升高(均为P<0.05)。结论MEG3在DR小鼠视网膜及高糖刺激的Müller细胞中表达均降低,其可通过负向调控miR-34a抑制Müller细胞活化及炎症因子的分泌。过表达MEG3可能成为DR治疗的新靶点。

Objective To investigate the effect and mechanism of maternally expressed gene 3(MEG3)on the activation of diabetic retinopathy Müller cells and the secretion of inflammatory cytokines.Methods A High-fat diet combined with intraperitoneal injection of streptozotocin(STZ)was used to construct an in vivo model of diabetic retinopathy(DR)in mice.High glucose stimulated human retinal Müller cell line MIO-M1 to construct DR in vitro model.Immunofluorescence and Western blot were used to detect the expression of glial fibrillary acidic protein(GFAP)in mouse retina and Müller cells.Western blot and enzyme linked immunosorbent assay(ELISA)were used to detect the expression of vascular endothelial growth factor(VEGF)in mouse retina and cell culture supernatant.ELISA was used to detect the expression of IL-1βin mouse retina and cell culture supernatant.We interfered the expression of MEG3 and miR-34a through transfecting pcDNA-MEG3 and miR-34a mimic to Müller cells separately or simultaneously.qRT-PCR was used to detect MEG3 and miR-34a expression.Results Compared with the normal control group,the expression levels of GFAP,VEGF and IL-1βprotein in the retina of the DR group increased(all P<0.05),and the expression of MEG3 mRNA decreased(P<0.01).Compared with the control group,the expression level of MEG3 mRNA in Müller cells of the high glucose group decreased(P<0.01),while the expression levels of GFAP,VEGF and IL-1βprotein increased(all P<0.05).Compared with the high glucose group,the expression levels of GFAP,VEGF and IL-1βprotein in the high glucose+pcDNA-MEG3 group were all decreased(all P<0.05).Compared with the normal control group,the expression levels of miR-34a in the retina of DR mice and Müller cells stimulated by high glucose increased(both P<0.05).Compared with the pcDNA group,the expression level of miR-34a in the pcDNA-MEG3 group was reduced(P<0.01).Compared with the pcDNA+NC mimic group,the expression levels of GFAP,VEGF and IL-1βprotein increased in the pcDNA+miR-34a mimic group(all P<0.05),while the pcDNA-MEG3+NC mimic group decreased(all P<0.05).Compared with the pcDNA-MEG3+miR-34a mimic group,the expression levels of GFAP,VEGF and IL-1βprotein increased(all P<0.05).Conclusion MEG3 expression level is decreased in the retina of DR mice and high glucose-stimulated Müller cells,and it can inhibit miR-34a by inhibiting Müller cells activation and inflammatory factors secretion.Overexpression of MEG3 may become a new target for DR therapy.