锌指蛋白A20对抑制ox-LDL诱导的平滑肌细胞LOX-1、TLR-4表达的作用

目的 探讨锌指蛋白A20对氧化性低密度脂蛋白（ox-LDL）诱导的血管平滑肌细胞血凝素样氧化低密度脂蛋白受体（LOX-1）和toll样受体-4（TLR-4）表达的作用.方法 体外培养SD大鼠主动脉血管平滑肌细胞（VSMC）,简单随机化分成4组：A组（对照组）;B组（OX-LDL组）;C组（A20组）;D组（ox-LDL＋A20组）.收集以上各组细胞,用RT-PCR检测LOX-1mRNA和TLR-4 mRNA的表达;提取核蛋白,并用western blot的方法检测NF-κ B核易位的量.结果 ox-LDL刺激大鼠主动脉平滑肌细胞后LOX-1mRNA和TLR-4 mRNA的表达明显增加及核因子κ B（NF-κ B）的活化均明显增加.转染含A20基因质粒的平滑肌细胞TLR-4 mRNA的表达达到正常水平,LOX-1 mRNA的表达及NF-κ B的核移位的量甚至降低到正常水平以下.结论 ox-LDL诱导的平滑肌细胞LOX-1mRNA和TLR-4 mRNA表达增加,可能由此激活TLR-4/NF-κB信号系统,启动动脉壁的炎症反应,触发动脉粥样硬化发生.A20明显抑制了ox-LDL对平滑肌细胞的上述诱导作用,可能由此阻断了ox-LDL引发的不断级联扩大的正反馈效应.阻止了动脉粥样硬化的发展.

Zinc finger protein A20 inhibits expression of LOX-1 and TLR-4 in smooth muscle cells induced by oxidized low density lipoprotein

Objective To investigate the effect of zinc finger protein A20 on the expression of LOX- 1 and TLR-4 induced by oxidized low density lipoprotein （ox-LDL） in vascular smooth muscle cells （VSMC）. Methods Rat thoracic aorta VSMCs were primarily cultured and randomly divided into 4 groups： group A （control group, VSMCs were cultured with normal DMEM medium with 10% fetal bovine serum for 48 hours）; group B （ox-LDL group, VSMCs were cultured in normal DMEM medium with 10% fetal bovine serum for 24h, and then incubated with 50 μ g/ml ox-LDL for 24h）; group C （A20 group, VSMCs were transfectecl with plamid containing A20 gene and cultured for 48h） and group D （ox-LDL＋A20 group, VSMCs were transfected with plamid containing A20 gene and were cultured for 24 h, then incubated with 50μ g/ml ox-LDL for 24h）. TLR4 and LOX-1 mRNA expression were measured by RT-PCR. The nuclear translocation of NF- κB was measured by Western blot analysis. Results After VSMCs incubated with ox-LDL, the expression of LOX-1 and TLR-4 mRNA reached a higher level and NF-κB was markedly activated. When VSMCs were transfected with plamid containing A20 gene, the expression of TLR-4 mRNA returned to normal levels; the expression of LOX-1 mRNA and the NF- κB nuclear translocation were even lower than normal level. Conclusion ox-LDL can induce the expression of LQX-1 and TLR-4 mRNA, which may activate TLR-4/NF- κB signaling system inducing the inflammatory response in arterial wall, and triggering the process of atherosclerosis. A20 can inhibit LOX-1 and TLR-4 mRNA expression and may prevent the development of atherosclerosis.