ERK等激酶途径介导五味子提取物激活Nrf2信号通路的研究

摘要

目的考察细胞外信号调节激酶（ERK）、 p38丝裂原活化蛋白激酶（p38MAPK）等不同激酶途径在五味子提取物（FSE）激活核因子相关因子（Nrf2）信号通路中的作用。方法给予不同的蛋白酶抑制剂预处理2 h后再以FSE干扰24 h；采用逆转录—聚合酶链反应（RT－PCR）法检测Nrf2及下游靶基因HO－1、 NQO1、 P－gp、 MRP2 mRNA的表达； Western blotting法检测蛋白水平及Nrf2核转位。结果 RT－PCR结果显示： PD98059、 SB203580、 Rottlerin处理可抑制FSE对HO－1、NQO1、 P－gp、 MRP2 mRNA的诱导作用，但仅SB203580、 Rottlerin处理可抑制FSE对Nrf2 mRNA的表达。 Western blotting结果显示： PD98059、 SB203580、 Rottlerin处理可抑制FSE对HO－1、 P－gp蛋白的诱导作用；各抑制剂处理后均能诱导胞浆中Nrf2蛋白的表达，但PD98059、 SB203580处理可抑制Nrf2核转位。结论 FSE激活Nrf2信号通路机制可能与ERK、p38MAPK直接磷酸化Nrf2，促进Nrf2入核增加其核聚积有关。%Objective To observe the influence of several kinase pathways such as extracellular signal-regulated kinase ( ERK) , and mitogen-activated protein kinase p38 ( p38MAPK) on nuclear factor erythroid 2-related factor 2 (Nrf2) pathway activated by Fructus Schisandrae extracts (FSE) . Methods HepG2 cells were treated by FSE for 24 hours after pretreatment with protein kinase inhibitors for 2 hours. The mRNA expression levels of Nrf2 and downstream target genes heme oxygenase-1 (HO-1), NAD (P) H quinine oxidoreductase 1(NQO1), P-glycoprotein ( P-gp) and multidrug resistance-associated protein 2 ( MRP2) were detected by real-time polymerase chain reaction ( RT-PCR) , and their protein expression levels and Nrf2 nuclear translocation were measured by Western blotting method. Results RT-PCR results showed that the mRNA expression levels of HO-1, NQO1, P-gp and MRP2 activated by FSE in HepG2 cells were inhibited by PD98059, SB203580 and Rottlerin, and the mRNA expression of Nrf2 was suppressed only by SB203580 and Rottlerin. Western blotting results showed that the mRNA expression levels of HO-1 and P-gp activated by SCE in HepG2 cells were inhibited by PD98059, SB203580 and Rottlerin. In addition, the protein expression of Nrf2 in HepG2 cytoplasm was increased by the above three inhibitors, and nuclear translocation of Nrf2 was inhibited by PD98059 and SB203580. Conclusion The mechanism of FSE activating Nrf2 pathway may be associated with the increase of Nrf2 nuclear translocation through the direct phosphorylation of Nrf2 induced by ERK and p38MAPK.