LOX-1在ox-LDL诱导人肾小球系膜细胞TGF-β1表达的作用

Role of LOX-1 in oxidized low-density lipoprotein-induced expression of transforming growth factor-β1 in human glomerular mesangial cells

目的:探讨血凝素样氧化低密度脂蛋白受体1(LOX-1)在氧化低密度脂蛋白(ox-LDL)诱导人肾小球系膜细胞(HGMC)表达转化生长因子(TGF-β1)中的作用。方法:体外培养HGMC,在不同时间加入不同浓度的ox-LDL及LOX-1阻滞性抗体JTX92,用半定量RT-PCR法检测细胞LOX-1和TGF-β1mRNA表达,用Westernblot法检测细胞LOX-1蛋白合成,用酶联免疫吸附法(ELISA)检测细胞培养液中TGF-β1浓度。结果:ox-LDL以时间和浓度依赖的方式增加LOX-1mRNA和蛋白表达的同时,也以时间和浓度依赖的方式增加细胞内TGF-β1mRNA表达和培养液中TGFβ1蛋白的含量,JTX92(10μg/ml)可以明显抑制LOX-1和TGF-β1的表达(P<0.01)。结论:ox-LDL通过激活LOX-1调节HGMCTGF-β1基因表达、蛋白合成与分泌。

Objective：To study the role of lectin-like oxidized low-density lipoprotein receptor-1 （LOX-1）, the specific scavenger receptor for oxidized low-density hpoprotein （ox-LDL）,in the expression of transforming growth factor-β1 （TGF-β1） induced by ox-LDL in human glomerular mesangial cells. Methods：Human glomerular mesangial cells were incubated with ox-LDL （10 to 80 μg/ml） for 6 to 24 hours and then pretreated with JTX92 （10 μg/ml）,a blocking antibody to LOX-1 ,before exposed to ox-LDL. The expressions of LOX-1 and TGF- β1 mRNA and the expression of LOX-1 protein were detennined by reverse transcriptase polymerase chain reaction and Western blot, respectively. The level of TGF-β1 protein was measured by enzyme-linked immunosorbent assay.Results： ox-LDL increased the expressions of both LOX-1 and TGF-β1 mRNA and protein in a concentration-and time-dependent manner,which was inhibited by JTX92. The effect of ox-LDL was mediated by its scavenger receptor LOX-1 ,because the pretreatment of HGMC with a blocking antibody to LOX-1 prevented the expression of TGF β1 in response to ox-LDL （P 〈 0.01 ）.Conclusion：ox-LDL may regulate the expression of TGF-β1 mRNA and the synthesis and secretion of TGF-β1 protein via activating LOX-1 in human glomerular mesangial cells.