Department of Biotechnology, Graduate School of Life Sciences and Biotechnology, Korea University, Seoul 136-713, South Korea.
Bioorg Med Chem Lett. 2012 Jun 15;22(12):4094-9. doi: 10.1016/j.bmcl.2012.04.071. Epub 2012 Apr 24.
The present study reports a novel liver X receptor (LXR) activator, ethyl 2,4,6-trihydroxybenzoate (ETB), isolated from Celtis biondii. Using a reporter gene assay, time-resolved fluorescence resonance energy transfer (TR-FRET), and surface plasmon resonance (SPR) analysis, we showed that ETB directly bound to and stimulated the transcriptional activity of LXR-α and LXR-β. In macrophages, hepatocytes, and intestinal cells, ETB suppressed cellular cholesterol accumulation in a dose-dependent manner and induced the transcriptional activation of LXR-α/-β-responsive genes. Notably, ETB did not induce lipogenic gene expression or cellular triglyceride accumulation in hepatocytes. These results suggest that ETB is a dual-LXR modulator that regulates the expression of key genes in cholesterol homeostasis in multiple cells without inducing lipid accumulation in HepG2 cells.
本研究报告了一种新型的肝 X 受体 (LXR) 激活剂,即从朴树中分离得到的 2,4,6-三羟基苯甲酸乙酯 (ETB)。通过报告基因检测、时间分辨荧光共振能量转移 (TR-FRET) 和表面等离子体共振 (SPR) 分析,我们发现 ETB 可直接与 LXR-α 和 LXR-β 结合并刺激其转录活性。在巨噬细胞、肝细胞和肠细胞中,ETB 呈剂量依赖性抑制细胞内胆固醇蓄积,并诱导 LXR-α/-β 反应基因的转录激活。值得注意的是,ETB 不会诱导肝细胞中脂肪生成基因的表达或细胞内三酰甘油的蓄积。这些结果表明,ETB 是一种双重 LXR 调节剂,可调节胆固醇稳态关键基因在多种细胞中的表达,而不会诱导 HepG2 细胞中的脂质蓄积。