丝裂原活化蛋白磷酸酶1调控法尼醇X受体转录活性的研究

Study on regulation of transcription activity of farnesoid X receptor by mitogen activated protein kinase phosphatase-1

目的:探讨丝裂原活化蛋白磷酸酶1(mitogen activated protein kinase phosphatase-1,MKP-1)调控法尼醇X受体(farnesoid X receptor,FXR)转录活性的作用。方法:采用实时定量PCR和蛋白印迹法,检测肥胖小鼠模型肝脏FXR和MKP-1的mRNA和蛋白表达;采用免疫共沉淀和荧光素酶报告基因实验,探讨MKP-1调控FXR转录活性的作用。结果:肥胖小鼠的肝脏组织中,FXR的表达显著下调(P<0.05),而MKP-1的表达则显著增加(P<0.05);免疫共沉淀和荧光素酶报告基因实验结果显示,MKP-1与FXR间存在蛋白-蛋白相互作用。MKP-1过表达后,可抑制FXR的转录活性(P<0.05),而干扰MKP-1的表达则可上调其转录活性(P<0.05)。结论:MKP-1可能作为FXR的辅抑制因子,从而参与肝脏糖脂代谢的调控。

Objective： To investigate the role of mitogen activated protein kinase phosphatase-l（MKP-1） in regulation of transcription activity of farnesoid X receptor. Methods： Expression levels of FXR and MKP-1 mRNA and protein in liver specimens of obese mice were measured by real-time quantitative PCR and Western blot, respectively. The effect of MKP-1 on regulating transcription activity of FXR was determined by co-immunoprecipitaion and luciferase reporter assays. Results： FXR expression was down-regulated and MKP-1 expression was up-regulated in liver of obese mice （P〈 0.05）. The protein-protein interaction of MKP-1 and FXR was confirmed by coimmunoprecipitation and lueiferase reporter assays. Overexpression of MKP-1 could inhibit FXR transcription activity, while MKP-1 silencing could promote transcription activity of FXR. Conclusions： MKP-1 might be a co-repressor for FXR and play a role in the regulation of hepatic glucose and lipid metabolism.