非诺贝特与过氧化体增殖物激活型受体α对人肝瘤细胞1型纤溶酶原激活物抑制剂表达的影响

Effects of fenofibrate and peroxisome proliferator-activated receptor α on the expression of plasminogen activator inhibitor type-1 in HepG2 cells

目的探讨非诺贝特对人肝瘤细胞株(HepG2)细胞1型纤维酶原激活物抑制剂(PAI-1)表达的影响及机制。方法用不同浓度非诺贝特刺激HepG2细胞,采用半定量逆转录聚合酶链反应(RT-PCR)法检测PAI-1mRNA水平,发色底物法检测PAI-1的活性变化。构建4个荧光素酶报告基因质粒,分别由PAI-1启动子序列从-804至+17间不同长度片段驱动,体外转染HepG2细胞,检测荧光素酶的活性。结果非诺贝特能使HepG2细胞PAI-1mRNA表达及蛋白活性显著降低,且呈一定剂量依赖性;还可使PAI-1转录活性显著降低;当转染质粒含有PAI-1启动子序列-636^+17、-449^+17-、276^+17 bp 3个片段时,荧光素酶活性显著增高;共转染过氧化体增殖物激活型受体α(PPARα)表达质粒(PPAR-αpSG5)的细胞在非诺贝特诱导下PAI-1转录活性显著降低。结论非诺贝特可以抑制HepG2细胞PAI-1mRNA表达及其活性,调节PAI-1的基因转录,PPARα参与非诺贝特对PAI-1基因的表达调控。

Objective To investigate the effect and mechanisms of fenofibrate on PAI-1 expression in HepG2 cells. Methods HepG2 cells were exposed to fenofibrate at various concentrations. RT-PCR and ELISA were used to determine the expression of PAI-1. Four lucifemse reporter gene plasmids containing different human PAI-1 gene promoter from - 804 to ＋ 17 were constructed and tmnsfected into HepG2 cells. The transcriptional activity of PAI-1 was demonstrated by the luciferase activity. Results Fenofibrate could remarkably depress PAI-1 mRNA expression and protein activity in a concentration-dependent manner, and depress the level of PAI-1 transcription significantly. When the plasmids containing PAI-1 gene promoter -636 ～ ＋ 17, -449 ～ ＋ 17, -276 ～ ＋ 17 bp were transfected, fenofibrate increased the luciferase activity remarkably. When cotraxtsfected with PPARα-pSG5, fenofibrate could depress the level of PAI-1 transcription further more. Conclusions Fenofibrate could regulate PAI-1 mRNA expression and gene transcription. PPARα was involved in the regulation of PAI-1 gene expression.