目的探讨微小RNA(miR)-155对过氧化氢(H 2O 2)诱导晶状体上皮细胞(LECs)氧化应激损伤的作用及其调控沉默信息调节因子相关酶1(SIRT1)的机制。
方法取对数生长期HLE-B3细胞株，分别于0、50、100、200、400、800 μmol/L H 2O 2条件下培养24 h，采用MTT法检测细胞存活率，筛选构建氧化应激损伤模型的H 2O 2最佳作用浓度。将细胞分为6个组，其中空白对照组不作处理，模型对照组细胞于100 μmol/L H 2O 2条件下培养，miR-155拟似物组、miR-155拟似物对照组、miR-155抑制剂组和miR-155抑制剂对照组细胞分别转染miR-155拟似物、miR-155拟似物对照、miR-155抑制剂、miR-155抑制剂对照并于100 μmol/L H 2O 2条件下培养。各组细胞培养24 h，倒置显微镜下观察细胞形态；采用荧光定量PCR法检测细胞miR-155和SIRT1 mRNA相对表达量；采用流式细胞术检测细胞凋亡率；采用二氯二氢荧光素-乙酰乙酸酯(DCFH-DA)荧光探针法检测活性氧簇(ROS)含量；采用ELISA法检测超氧化物歧化酶(SOD)活性和丙二醛(MDA)浓度；采用双荧光素酶报告基因系统检测miR-155对SIRT1的靶向性；采用Western blot法检测细胞SIRT1、B细胞淋巴瘤/白血病-2基因(bcl-2)、bcl-2相关X蛋白(bax)、活化的半胱氨酸天冬氨酸酶3(cleaved-Caspase-3)蛋白表达。
结果随H 2O 2浓度增加，细胞存活率逐渐降低，各不同浓度间细胞存活率比较差异均有统计学意义(均 P<0.05)，选取100 μmol/L作为H 2O 2的实验浓度。空白对照组细胞贴壁生长良好；模型对照组细胞数量减少，部分存活细胞形态发生改变，边界模糊不清；miR-155拟似物组细胞数量少于模型对照组，细胞固有形态发生改变；miR-155抑制剂组细胞数量多于模型对照组，细胞生长状态良好。与模型对照组比较，miR-155拟似物组细胞miR-155相对表达量明显升高，SIRT1 mRNA相对表达量明显降低，细胞凋亡率、ROS含量和MDA浓度升高，SOD活性降低，SIRT1、bcl-2蛋白相对表达量及bcl-2/bax明显降低、bax、cleaved-Caspase-3蛋白相对表达量明显升高，差异均有统计学意义(均 P<0.05)；miR-155抑制剂组细胞miR-155相对表达量明显降低，SIRT1 mRNA相对表达量明显升高，细胞凋亡率、ROS含量、MDA浓度明显降低，SOD活性明显升高，SIRT1、bcl-2蛋白相对表达量及bcl-2/bax明显升高、bax、cleaved-Caspase-3蛋白相对表达量明显降低，差异均有统计学意义(均 P<0.05)。转染miR-155拟似物细胞的野生型SIRT1相对荧光素酶活性为0.41±0.07，明显低于转染miR-155拟似物对照细胞的1.00±0.11，转染miR-155抑制剂细胞的野生型SIRT1相对荧光素酶活性为1.98±0.17，明显高于转染miR-155抑制剂对照细胞的1.00±0.12，差异均有统计学意义( t＝7.838、8.157，均 P<0.05)；各转染细胞对突变型SIRT1相对荧光素酶活性无明显影响。
结论miR-155参与H 2O 2诱导的LECs氧化损伤，其过表达可靶向抑制SIRT1表达，发挥细胞损伤作用。
ObjectiveTo investigate the role of microRNA (miR)-155 in hydrogen peroxide (H 2O 2)-induced oxidative stress injury in lens epithelial cells (LECs) and its mechanism regulating silent information regulator factor related enzymes 1 (SIRT1).
MethodsThe HLE-B3 at the logarithmic growth phase was taken and cultured for 24 hours under different concentrations of H 2O 2 (0, 50, 100, 200, 400, 800 μmol/L), and the cell viability was detected by MTT assay to determine the optimal concentration of H 2O 2 for establishing an oxidative stress injury model.HLE-B3 cells were divided into 6 groups, untreated blank control group, model control group cultured with 100 μmol/L H 2O 2, miR-155 mimics group transfected with miR-155 mimics, miR-155 mimics negative control group transfected with miR-155 mimics negative control, miR-155 inhibitor group transfected with miR-155 inhibitor, and miR-155 inhibitor negative control group transfected with miR-155 inhibitor negative control.Transfected cells were cultured with 100 μmol/L H 2O 2.Cells in various groups were cultured for 24 hours, and cell morphology was observed under an inverted microscope.The relative expression of miR-155 and SIRT1 mRNA in cells was assayed by fluorescent quantitative PCR.Cell apoptosis rates were detected by flow cytometry.Reactive oxygen species (ROS) content was identified by 2', 7'-dichlorofluorescein diacetate (DCFH-DA) fluorescent probe method.Superoxide dismutase (SOD) activity and malondialdehyde (MDA) concentration were measured by ELISA method.The targeting of SIRT1 by miR-155 was tested by dual luciferase reporter gene system.Expressions of SIRT1, B-cell lymphoma/leukemia-2 gene (bcl-2), bcl-2 associated X protein (bax), cleaved-cysteine aspartase 3 (cleaved-Caspase-3) proteins were determined by Western blot.
ResultsWith the increase of H 2O 2 concentration, the cell viability gradually decreased, and the differences in cell viability among different concentrations were statistically significant (all at P<0.05), and 100 μmol/L was selected as the experimental concentration.Cells in blank control group grew well adherently.The number of cells in model control group decreased, and the morphology of some surviving cells changed, and their boundaries were blurred.There were fewer cells in miR-155 mimics group than model control group, and the cell morphology changed.There were more cells in miR-155 inhibitor group than model control group, and the cells grew well.Compared with model control group, the relative expression level of miR-155, the apoptosis rate, ROS content, MDA concentration, as well as the relative expression levels of bax and cleaved-Caspase-3 proteins were increased, and the relative expression level of SIRT1 mRNA, the SOD activity, the relative expression of SIRT1 and bcl-2 proteins, as well as bcl-2/bax were decreased in miR-155 mimics group, and the differences were statistically significant (all at P<0.05). Compared with model control group, the relative expression of miR-155, the apoptosis rate, ROS content, MDA concentration, as well as the relative expression levels of bax and cleaved-Caspase-3 proteins were decreased, and the relative expression level of SIRT1 mRNA, SOD activity, the relative expression levels of SIRT1 and bcl-2 protein, as well as bcl-2/bax were significantly increased in miR-155 inhibitor group, and the differences were statistically significant (all at P<0.05). The relative luciferase activity of wild-type SIRT1 in cells transfected with miR-155 mimics was 0.41±0.07, which was significantly weaker than 1.00±0.11 in cells transfected with miR-155 mimics negative control, and the relative luciferase activity of wild-type SIRT1 in cells transfected with miR-155 inhibitor was 1.98±0.17, which was significantly higher than 1.00±0.12 in cells transfected with miR-155 inhibitor negative control, showing statistically significant differences ( t=7.838, 8.157; both at P<0.05). No obvious effect on the relative luciferase activity of mutant SIRT1 was found in transfected cells.
ConclusionsmiR-155 is involved in H 2O 2-induced oxidative damage of LECs, and its overexpression can target the expression of SIRT1 and play a role in cell injury.
牛艳桃,张丽,谢文芳. miR-155在过氧化氢诱导晶状体上皮细胞氧化应激损伤中的作用及靶向SIRT1调控机制[J]. 中华实验眼科杂志,2022,40(05)：404-413.
DOI:10.3760/cma.j.cn115989-20201104-00735版权归中华医学会所有。
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牛艳桃：实验设计和实施、文章撰写；张丽：实验设计、文章修改及定稿；谢文芳：实验实施、数据采集及分析
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