Gu Ming, Zhang Yu, Liu Chuhe, Wang Dongshan, Feng Li, Fan Shengjie, Yang Baican, Tong Qingchun, Ji Guang, Huang Cheng
School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
School of Life Science and Technology, Shanghai Tech University, Shanghai, China.
Br J Pharmacol. 2017 Sep;174(18):3032-3044. doi: 10.1111/bph.13933. Epub 2017 Aug 11.
Morin is a natural occurring flavonoid in many dietary plants and has a wide range of beneficial effects on metabolism; however, the mechanism underlying its action remains elusive.
A reporter assay and the time-resolved FRET assay were used to identify morin as a dual antagonist of liver X receptor (LXR)-α and -β. Morin (100 mg 100 g diet) was administered to high-fat diet-induced obese or LXRβ mice. The pharmacological effects and mechanism of action of morin were evaluated by Western blot and RT-PCR analyses.
From the in vitro assays, morin was shown to be a dual antagonist of LXRα and LXRβ. In vivo, morin blunted the development of liver hepatic steatosis, reduced body weight gains, lowered triglyceride levels and improved glucose and insulin tolerance in mice fed a high-fat diet. Mechanistically, morin inhibited 3T3-L1 adipocyte differentiation and lipid formation in human hepatic HepG2 cells and suppressed the mRNA expression of genes downstream of LXR. Consistently, the effects of morin on metabolic disorders were attenuated in LXRβ mice.
Our data reveal that morin is a dual antagonist of LXRα and LXRβ and suggest that morin may alleviate hepatic steatosis and other associated metabolic disorders via the suppression of LXR signalling and, therefore, shows promise as a novel therapy or nutraceutical for nonalcoholic fatty liver disease.
桑色素是许多食用植物中天然存在的黄酮类化合物,对新陈代谢具有广泛的有益作用;然而,其作用的潜在机制仍不清楚。
采用报告基因检测法和时间分辨荧光共振能量转移检测法确定桑色素为肝脏X受体(LXR)-α和-β的双重拮抗剂。将桑色素(100毫克/100克饮食)给予高脂饮食诱导的肥胖小鼠或LXRβ小鼠。通过蛋白质免疫印迹法和逆转录-聚合酶链反应分析评估桑色素的药理作用和作用机制。
体外实验表明,桑色素是LXRα和LXRβ的双重拮抗剂。在体内,桑色素可抑制高脂饮食喂养小鼠肝脏肝脂肪变性的发展,减少体重增加,降低甘油三酯水平,并改善葡萄糖和胰岛素耐受性。机制上,桑色素抑制3T3-L1脂肪细胞分化和人肝脏HepG2细胞中的脂质形成,并抑制LXR下游基因的mRNA表达。同样,在LXRβ小鼠中,桑色素对代谢紊乱的作用减弱。
我们的数据表明,桑色素是LXRα和LXRβ的双重拮抗剂,并提示桑色素可能通过抑制LXR信号通路减轻肝脂肪变性和其他相关代谢紊乱,因此有望成为治疗非酒精性脂肪性肝病的新型疗法或营养保健品。