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目的探讨法尼酯X受体(farnesoid X receptor,FXR)在肝细胞中对B类清道夫受体I(scavenger receptor class B type I,SR-BI)表达的影响及可能机制。方法用FXR的特异性激动剂GW4064刺激胚胎肝细胞L02,经RT-PCR检测FXR特异性靶基因SHP(small heterodimer partner)mRNA的表达;经RT-PCR、荧光实时定量PCR和Western blot检测SR-BI的表达;在线分析、预测SR-BI基因启动子区中FXR的可能结合位点;最后经RT-PCR检测FXR的靶基因PPARγ(过氧化物酶体增殖物激活受体γ)mRNA的表达。结果FXR的特异性配体GW4064作用于L02细胞后,SHP mRNA表达明显上调,表明FXR在L02细胞中具有功能活性。FXR活化后可在转录和翻译水平上调SR-BI的表达,同时上调PPARγ的表达。经在线分析,未在SR-BI启动子区域找到FXR的经典结合位点。结论FXR在肝细胞中可上调SR-BI的表达,其机制可能与上调PPARγ有关。
Objective To investigate the effect of farnesoid X receptor (FXR) on the expression of scavenger receptor class B type I (SR-BI) in hepatocytes and its possible mechanism. Methods The L02 cells were stimulated with the specific agonist GW4064 of FXR to detect the mRNA expression of SHR (small heterodimer partner) in FXR. RT-PCR, real-time quantitative PCR and Western blot were used to detect the expression of SR- BI expression was analyzed online to predict the possible binding sites of FXR in SR-BI promoter region. Finally, the expression of FXR target gene PPARγ (peroxisome proliferator-activated receptor γ) mRNA was detected by RT-PCR . Results After FXS-specific ligand GW4064 was administered to L02 cells, the SHP mRNA expression was significantly up-regulated, indicating that FXR has a functional activity in L02 cells. After activation of FXR, the expression of SR-BI can be upregulated and the expression of PPARγ can be up-regulated at the transcriptional and translational level. By online analysis, the classical binding site for FXR was not found in the SR-BI promoter region. Conclusion FXR can upregulate the expression of SR-BI in hepatocytes, which may be related to the up-regulation of PPARγ.