目的:通过在人小梁网细胞(human trabecular meshwork cell,HTMC)中过表达沉默信息调节因子2相关酶1(silent information regulator 1,SIRT1),探讨SIRT1对氧化应激下HTMC功能的影响。方法:将SIRT1过表达慢病毒和GFP阴性对照慢病毒按照最佳(multiplicity of infection,MOI)分别转染入HTMC,并用实时定量PCR法对SIRT1是否在细胞中过表达进行验证。实验分为以下4组:正常组、H2O2组、H2O2+Lv-SIRT1-OE(过表达)组、H2O2+Lv-GFP组,分别采用Transwell法和CCK8法检测氧化应激下HTMC的迁移能力和活性。两组间比较采用独立样本t检验。结果:在正常组、H2O2组、H2O2+Lv-SIRT1-OE组、H2O2+Lv-GFP组这4组中,Transwel l实验结果分别为436±73、254±25、510±51、327±46,H2O2+Lv-SIRT1-OE组分别与H2O2组和H2O2+Lv-GFP组差异均有统计学意义(P<0.01)。CCK8法结果显示,H2O2+Lv-SIRT1-OE组分别与H2O2组和H2O2+Lv-GFP组相比差异均有统计学意义(P<0.01)。H2O2+Lv-SIRT1-OE组分别与H2O2组和阴性对照组(H2O2+Lv-GFP)相比,Bax表达水平明显下降,Bcl-2表达水平明显提高,差异均有统计学意义(P<0.01)。ROS活性氧测定显示H2O2+Lv-SIRT1-OE组比H2O2组的细胞活性氧水平显著降低(P<0.05)。结论:在HTMC中过表达SIRT1能有效降低氧化应激对HTMC迁移能力和活性的影响,从而对HTMC起到一定的保护作用,为后续研究SIRT1保护氧化应激下HTMC的调控机制打下基础。
(A) HTMC was observed under the optical microscope after GFP-negative control lentivirus transfection for 48 hours (100 μm);(B) HTMC was observed under the fluorescence microscope after GFP-negative control lentivirus transfection for 48 hours (100 μm);(C) HTMC was observed under the optical microscope after SIRT1-ovexpressed lentivirus transfection for 48 hours (100 μm); (D) HTMCwas observed under the fluorescence microscope after SIRT1-ovexpressed lentivirus transfection for 48 hours (100 μm).
2.2 SIRT1在转染后HTMC的表达水平明显提高
分别提取感染了SIRT1过表达慢病毒或GFP阴性对照慢病毒的HTMC的总RNA,反转录后进行Real-time PCR实验,检测两组中SIRT1的表达水平差异,使用2???Ct法计算基因的相对表达倍数变化,结果显示:与GFP阴性对照组相比,SIRT1过表达组中SIRT1的表达水平明显高于对照组(1.000±0.056 vs 0.095±0.005,P<0.0001);同样地,SIRT1过表达组中SIRT1的蛋白表达水平也明显高于对照组(图2)。
图2 SIRT1过表达组与GFP阴性对照组中SIRT1在mRNA水平和蛋白水平的比较
Figure 2 Comparison of SIRT1 mRNA and protein levels between SIRT1 overexpression group and GFP negative control group
(A) View of normal HTMC; (B) View of HTMC treated by H2O2 for 2 hours; (C) View of HTMC transfected by SIRT1-ovexpressed lentivirus under 2-hour-H2O2 treatment; (D) View of HTMC transfected by GFP-negative control lentivirus under 2-hour-H2O2 treatment;(E) View of the number of HTMC migration after different treatments detected by transwell assay (F=19.600, P<0.001). *P<0.05, **P<0.01,***P<0.001, ****P<0.0001.
2.4 SIRT1过表达能有效降低氧化应激对HTMC细胞活性的影响
CCK8增殖实验结果显示: H2O2刺激组与正常对照组在细胞活性上,差异有统计学意义( P < 0.01)。同时,H2O2+Lv-SIRT1-OE组分别与H2O2组和阴性对照组(H2O2+Lv-GFP)相比差异均有统计学意义(P <0.01),且与正常组的差异没有统计学意义(P>0.05),表明SIRT1过表达能有效降低氧化应激对HTMC细胞活性的影响(图4 )。同时检测凋亡标志蛋白Bax和Bcl-2,H2O2+Lv-SIRT1-OE组分别与H2O2组和阴性对照组( H2O2+Lv-GFP)相比,Bax表达水平明显下降,Bcl-2表达水平明显提高,差异均有统计学意义(P<0.01,图5)。此外,通过ROS活性氧测定,笔者发现H2O2+Lv-SIRT1-OE组比H2O2组的细胞活性氧水平显著地降低(P <0.05),表明SIRT1过表达能有效降低氧化应激状态下HTMC的活性氧水平(表2)。
图4 SIRT1过表达对氧化应激下HTMC细胞活性的影响
Figure 4 Effect of SIRT1 overexpression on cell viability of HTMC under oxidative stress
(A) Comparison of mRNA expression levels of Bax between each group; (B) Comparison of mRNA expression levels of Bcl-2 between each group; (C) Comparison of protein levels of Bax and Bcl-2 between each group. Compared with the Normal group, **P<0.01;compared with the H2O2 group, ##P<0.01.
表2 SIRT1过表达对氧化应激下HTMC活性氧水平的影响
Table 2 Effffects of SIRT1 overexpression on reactive oxygen species of HTMC under oxidative stress
1、国家自然科学基金 (82070961);深圳市三名工程项目 (SZSM201812091);深圳市科创委国际合作项目
(GJHZ20190929145402153)。 This work was supported by the National Natural Science Foundation (82070961), Sanming Project of Medicine in Shenzhen
(SZSM201812091) and the International Science and Technology Cooperation Research Project of Shenzhen Science and Technology Innovation Committee
(GJHZ20190929145402153), China.
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