miR-26a在动脉粥样硬化发生中的作用

Study on the role of miR-26a in the development of atherosclerosis

目的 MicroRNAs通过调节血管平滑肌细胞(VSMCs)表型转化、增殖、迁移来影响动脉粥样硬化斑块形成,本文探讨miR-26a在动脉粥样硬化发生过程中的作用。方法采用终浓度为50 mg/L的氧化型低密度脂蛋白(ox LDL)诱导VSMCs构建动脉粥样硬化模型;采用real-time PCR检测VSMCs中miR-26a表达;运用western blot检测平滑肌α-肌动蛋白(SMα-actin)和平滑肌肌球蛋白重链(MYH11)蛋白表达;流式细胞仪、Brd U和transwell迁移实验检测VSMCs凋亡、增殖和迁移能力变化。结果 ox LDL诱导VSMCs中miR-26a表达显著升高(3.22±0.21 vs 1.03±0.03,t=10.56,P<0.001),anti-miR-26a转染VSMCs能显著减少ox LDL诱导的miR-26a表达(P<0.05)。功能学实验发现ox LDL显著下调VSMCs分化标志物SMα-actin和MYH11蛋白表达、抑制细胞凋亡、促进细胞增殖和迁移(P<0.05),而anti-miR-26a能够逆转ox LDL对VSMCs的作用(P<0.05)。结论 oxLDL处理的VSMCs中miR-26a异常升高,miR-26a促进VSMCs增殖和迁移并抑制细胞凋亡和分化,提示miR-26a在动脉粥样硬化过程中可能发挥关键作用。

Objective MicroRNAs affect atherosclerosis by regulating phenotype transformation, proliferation and migra- tion of vascular smooth muscle cells（VSMCs）. Our studies investigate the role of miR-26a in the development of athero- sclerosis. Methods VSMCs were treated with oxidized low density lipoprotein（oxLDL,50 mg/L） to generate atheroscle- rosis model. The expression of miR-26a was detected by real-time PCR. Western blot was used to determine the expression of smooth muscle α-actin（ SM ot-actin） and smooth muscle myosin heavy chain （MYH11 ） protein. Flow cytometry, BrdU and transwell migration assays were used to test apoptosis, proliferation and migration of VSMCs. Results oxLDL led to upregulation of miR-26a expression in VSMCs（3.22 ±0.21 vs. 1.03±0.03 ,t = 10.56 ,P 〈0.05 ）. However, anti-miR- 26a significantly reduced oxLDL-mediated upregulation of miR-26a in VSMCs（ P 〈 0.05 ）. Functional studies found that oxLDL significantly decreased the level of SM α-actin and MYHI 1 proteins,inhibited apoptosis and promoted cell proliferation and migration in VSMCs（ P 〈 0.05, respectively）. However, the effect of oxLDL on VSMCs were inverted by antimiR-26a（P 〈 0.05, respectively）. Conclusion VSMCs that are treated with oxLDL show aberrant upregulation of miR- 26a. MiR-26a promoted cell proliferation and migration of VSMCs. Furthermore, miR-26a inhibited apoptosis and cell differentiation in VSMCs, suggesting that miR-26a may play a critical role in the development of atherosclerosis.