Berberrubine and its analog, hydroxypropyl-berberrubine, regulate LDLR and PCSK9 expression via the ERK signal pathway to exert cholesterol-lowering effects in human hepatoma HepG2 cells
Berberrubine and its analog, hydroxypropyl-berberrubine, regulate LDLR and PCSK9 expression via the ERK signal pathway to exert cholesterol-lowering effects in human hepatoma HepG2 cells
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DOI：
10.1002/jcb.27102
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发表时间：
2019-02-01
影响因子：
4
通讯作者：
Kang, Ning
中科院分区：
文献类型：
--
作者：
Cao, Shijie;Xu, Peixiang;Kang, Ning
小檗碱（BBR）是中药黄连中主要的异喹啉类生物碱，通过上调肝脏低密度脂蛋白受体（LDLR）的表达而具有显著的降脂作用。在先前的研究中，我们已经表明，小檗红碱（M3），BBR在体内的主要代谢产物，显示最潜在的降血脂作用，通过上调LDLR表达在人肝癌细胞（HepG 2）相比，BBR和其他3种代谢产物。因此，9个M3类似物（A1-A9）在C9位置被修饰。本研究旨在通过评价其降胆固醇作用，阐明其降胆固醇作用的分子机制，寻找一种新的具有应用前景的药物。在本研究中，细胞胆固醇含量测定与商业胆固醇测定试剂盒。采用实时荧光定量聚合酶链反应（PCR）和蛋白质印迹法（Western blot）研究M3及其类似物降血脂作用的分子机制。在M3及其类似物中，羟丙基小檗红碱（A8）对LDLR表达的上调表现出最高的潜在作用，伴随着前蛋白转化酶枯草杆菌蛋白酶/kexin 9型（PCSK 9）信使RNA和蛋白水平的稳定下降。此外，用PD 98059抑制细胞外信号调节激酶（ERK）活性可阻止A8诱导的LDLR上调和PCSK 9下调。目前的研究表明，M3及其结构修饰类似物A8可以通过ERK信号通路调节肝脏LDLR和PCSK 9的表达，发挥降脂作用，而A8显示出更强的作用，可能是一种有希望的抗高脂血症候选药物。
Berberine (BBR), the major isoquinoline alkaloid in Chinese herb Rhizoma coptidis, has significant lipid-lowering effect by upregulating hepatic low-density lipoprotein receptor (LDLR) expression. In a previous study, we have indicated that berberrubine (M3), a major metabolite of BBR in vivo, displays the most potential hypolipidemic effects via upregulating LDLR expression in human hepatoma (HepG2) cells compared with BBR and 3 other metabolites. Accordingly,9 M3 analogs (A1-A9) were modified at the C9 position. We aimed to find a new promising agent by evaluating the cholesterol-lowering effect and clarifying the related molecular mechanism. In the current study, the cellular cholesterol content was assayed with a commercial cholesterol assay kit. Real-time polymerase chain reaction and Western blot assay were used to explore the molecular mechanism of M3 and its analogs on the hypolipidemic effect. Among M3 and its analogs, hydroxypropyl-berberrubine (A8) exhibited the highest potential effects on the upregulation of LDLR expression, which was accompanied by a steady decline of proprotein convertase subtilisin/kexin type 9 (PCSK9) messenger RNA and protein levels. Furthermore, inhibition of extracellular signal-regulated kinase (ERK) activity with PD98059 prevented the upregulation of LDLR and downregulation of PCSK9 induced by A8. The current study revealed that M3 and its structurally modified analog, A8, could regulate hepatic LDLR and PCSK9 expression to exert lipid-lowering effects via the ERK signal pathway, while A8 showed a stronger effect and might be a promising drug candidate against hyperlipidemia.