Objective: To investigate the effects of miRNA-130a-3p on autophagy and apoptosis induced by LPS in myocardial cells and its molecular mechanisms. Methods: H9C2 cells were divided into five groups: normal control group, LPS model group, miRNA negative control group miRNA-130a-3p mimics group(overexpression of miRNA-130a-3p) and miRNA-130a-3p mimics + LY294002 group(overexpression of miRNA-130a-3p + PI3K inhibitor). The LPS model group was induced by LPS at a final concentration of 10 μg/ml for 24 h. In the miRNA negative control group and miRNA-130a-3p mimics group, negative contro miRNA or miRNA-130a-3p mimics were transfected into H9C2 cells by lipo3000. After 24 h of culture, LPS was added into the medium for 24 hours. In the miRNA -130A-3P mimics + LY294002 group, miRNA -130A-3P mimics was transfected into H9C2 cells by using lipo3000, and LY294002 at a final concentration of 10 μmol/L was added to the culture medium for 24 h, followed by LPS at a concentration of 10 μg/ml for 24 h. The expression of miRNA-130a-3p mRNA in cells was detected by RT-qPCR. The CCK-8 assay was used to detect the cell viability. The contents of TNF-α, IL-6 and IL-1β were detected by ELISA assay. The contents of SOD and LDH in cell culture medium were detected by colorimetry. Western blot was used to detect the protein expressions of p-PI3K, p-AKT, Bax, Bcl-2, cleaved-caspase-3, LC3 and p62. Results: The results showed that the levels of miRNA-130a-3p mRNA, p-PI3K protein and p-AKT protein in LPS model cells were significantly lower than those in normal control group(P<0.01), and the expressions of p-PI3K, p-AKT protein in miRNA-130a-3p mimics group were increased significantly compared with LPS group(P<0.01,P<0.05). Compared with normal control group, the cell viability was decreased significantly and the contents of TNF-α, IL-6, IL-1β and LDH were increased significantly(P<0.01), the contents of SOD was decreased significantly in LPS group(P<0.01). The protein expression levels of Bax, cleaved-caspase-3 and p62 were increased significantly, while the expression level of Bcl-2 and LC3II/I ratio were decreased significantly in LPS group(P<0.01). miRNA-130a-3p mimics could increase the cell viability, decrease the contents of TNF-α, IL-6, IL-1β and LDH(P<0.01,P<0.05), increase the contents of SOD(P<0.05), decrease the expressions of Bax, cleaved caspase-3, p62(P<0.01), promote the expression of Bcl-2(P<0.01) and increase the ratio of LC3II/I(P<0.05). Compared with miRNA-130a-3p mimics group, LY294002 reversed the effects of miRNA-130a-3p mimics on cells. Conclusion: Overexpression miRNA-130a-3p could partly promote autophagy and inhibit cell apoptosis by activating PI3K/AKT signaling pathway to alleviate LPS-induced myocardial injury.
目的: 探讨miRNA-130a-3p对脂多糖(LPS)诱导的心肌细胞自噬与凋亡的影响及分子机制。方法: H9C2心肌细胞随机分为5组,即正常对照组,LPS模型组,miRNA阴性对照组(miRNA-negative control组),miRNA-130a-3p mimics组(过表达miRNA-130a-3p),miRNA-130a-3p mimics+LY294002组(过表达miRNA-130a-3p + PI3K抑制)。LPS模型组即终浓度为10 μg/ml的LPS诱导24 h,miRNA阴性对照组与miRNA-130a-3p mimics组是利用lipo3000将阴性对照miRNA及miRNA-130a-3p mimics转染至H9C2细胞,培养24 h后,再将LPS加入培养基中培养24 h。miRNA-130a-3p mimics + LY294002组是利用lipo3000将miRNA-130a-3p mimics转染至H9C2细胞,同时在培养基中加入10 μmol/L(终浓度)的LY294002,培养24 h后,再将浓度为10 μg/ml的LPS加入培养基中培养24 h。所有实验均重复5次以上。利用RT-qPCR检测细胞中miRNA-130a-3p mRNA的表达水平,利用CCK-8实验检测细胞活性,利用ELISA实验检测细胞培养液中肿瘤坏死因子-α(TNF-α),白细胞介素-6(IL-6),白细胞介素-1β (IL-1β)的含量,利用比色法检测细胞培养液中超氧化物歧化酶(SOD)、乳酸脱氢酶(LDH)的含量;利用Western blot检测细胞中p-PI3K蛋白,p-AKT蛋白,Bax蛋白,Bcl-2蛋白,cleaved-caspase-3蛋白,LC3蛋白,p62蛋白的表达水平。结果: 结果显示,与正常组相比较,LPS模型细胞中miRNA-130a-3p mRNA水平,p-PI3K蛋白与p-AKT蛋白的水平显著低于正常对照组(P<0.01);与LPS组相比较,miRNA-130a-3p mimics组细胞中p-PI3K,p-AKT蛋白的表达显著升高(P<0.01,P<0.05);与正常对照组相比较,LPS组细胞活性显著降低,细胞培养液中TNF-α,IL-6,IL-1β及 LDH的含量显著升高(P<0.01), SOD的含量显著降低(P<0.01),细胞中Bax蛋白,cleaved caspase-3蛋白,p62蛋白的表达显著升高(P<0.01),Bcl-2蛋白的表达和LC3II/I的比率显著降低(P<0.01);与LPS组相比较,miRNA-130a-3p mimics可提高细胞活性,降低细胞培养液中TNF-α,IL-6,IL-1β及LDH的含量(P<0.01,P<0.05),提高SOD的含量(P<0.05),降低细胞中Bax蛋白,cleaved caspase-3蛋白,p62蛋白的表达(P<0.01),促进Bcl-2蛋白的表达(P<0.01),提高LC3II/I的比率(P<0.05);与miRNA-130a-3p mimics组相比较,miRNA-130a-3p mimics+LY294002组,可部分逆转miRNA-130a-3p mimics对细胞的作用。结论: 过表达miRNA-130a-3p可部分通过激活PI3K/AKT信号通路促进细胞的自噬与抑制细胞凋亡,减轻LPS诱导的心肌细胞损伤。.
Keywords: PI3K/AKT signaling pathway; apoptosis; autophagy; cell injury; miRNA-130a-3p.