摘要:
目的 探讨特异性蛋白1(SP-1)通过miR-135b/HIF-1α轴对缺氧诱导的心肌细胞损伤的作用.方法 H9c2细胞进行缺氧处理后,转染si-SP-1,miR-135b mimic,anti-miR-135b和CoCl2(HIF-1α激活剂).采用蛋白质印迹(Western Blot,WB)法检测细胞SP-1和HIF-1α蛋白表达,实时荧光定量聚合酶链式反应(PCR)法检测miR-135b表达,CCK-8法检测细胞增殖,流式细胞术检测细胞凋亡和活性氧簇(ROS)含量,酶联免疫吸附(ELISA)试剂盒检测肿瘤坏死因子-α(TNF-α)、白细胞介素1β(IL-1β)、白细胞介素6(IL-6)的含量,生物信息学软件分析预测并通过荧光素酶报告基因实验验证miR-135b与HIF-1α间的靶向结合作用.结果 缺氧后,H9c2细胞内SP-1蛋白表达呈时间依赖性显著升高(P<0.05),miR-135b表达呈时间依赖性显著降低(P<0.05).与对照组(A组)相比,缺氧组(B组)H9c2细胞中SP-1和HIF-1α蛋白表达分别为1.467±0.055,1.437±0.082(P=0.014,0.017),细胞凋亡率[(14.591±1.863)%,P=0.000]、细胞上清液中TNF-α[(5.270±0.359)pg/mL,P=0.012]、IL-1β[(25.060±1.212)pg/mL,P=0.000]、IL-6[(82.707±4.550)pg/mL,P=0.000]和ROS(1.239±0.075,P=0.021)含量均显著升高(P<0.05),miR-135b表达(0.466±0.071,P=0.001)和细胞增殖能力[(67.242±3.490)%,P=0.008]均显著降低(P<0.05);与缺氧+siRNA组(C组)相比,缺氧+si-SP-1组(D组)H9c2细胞中SP-1(0.238±0.039,P=0.001)和HIF-1α的蛋白表达(1.126±0.100,P=0.032)、细胞凋亡率[(4.668±0.731)%,P=0.000]、细胞上清液中TNF-α[(3.901±0.354)pg/mL,P=0.022]、IL-1β[(17.198±1.216)pg/mL,P=0.002]、IL-6[(56.742±4.081)pg/mL,P=0.017]和ROS(1.086±0.090,P=0.028)含量均显著降低,miR-135b表达(0.752±0.094,P=0.015)和细胞增殖能力[(83.550±2.933)%,P=0.016]均显著升高.miR-135b靶向调控HIF-1α.CoCl2或anti-miR-135b会导致低表达SP-1的缺氧H9c2细胞增殖能力显著降低[(48.470±2.831)%比(63.728±4.192)%,P=0.000,0.021],细胞凋亡率[(41.076±1.117)%比(35.935±1.776)%,P=0.000,0.010]和细胞上清液中TNF-α[(6.211±0.408)pg/mL比(5.250±0.325)pg/mL,P=0.019,0.033]、IL-1β[(43.417±2.561)pg/mL比(38.675±1.956)pg/mL,P=0.013,0.021]、IL-6[(110.440±7.446)pg/mL比(108.767±6.589)pg/mL,P=0.026,0.031]和ROS[(1.351±0.073)比(1.327±0.041),P=0.073,0.035]的含量显著升高.结论 SP-1低表达通过miR-135b/HIF-1α轴发挥对缺氧诱导的心肌细胞损伤的保护作用.