Metformin inhibits hepatic gluconeogenesis through AMP-activated protein kinase-dependent regulation of the orphan nuclear receptor SHP
Metformin inhibits hepatic gluconeogenesis through AMP-activated protein kinase-dependent regulation of the orphan nuclear receptor SHP
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DOI：
10.2337/db07-0381
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发表时间：
2008-02-01
期刊：
影响因子：
7.7
通讯作者：
Choi, Hueng-Sik
中科院分区：
文献类型：
--
作者：
Kim, Yong Deuk;Park, Keun-Gyu;Choi, Hueng-Sik
目的：二甲双胍是一种常用于治疗2型糖尿病的抗糖尿病药物。本研究的目的是确定二甲双胍是否通过孤儿核受体小异二聚体配对(SHP，NR0B2)调节肝脏糖异生。研究设计与方法：我们通过Northern印迹分析二甲双胍和含有AMPK构成形式的腺病毒(Ad-AMPK)对肝脏SHP基因表达的调节，并通过肝细胞瞬时转染法评价SHP、PEPCK和G6Pase启动子的活性。在B6-LEP(ob/ob)小鼠中检测二甲双胍和腺病毒SHP(Ad-SHP)对肝细胞糖异生基因表达的影响。结果二甲双胍、5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside(AICAR)和Ad-AMPK均可诱导肝细胞SHP基因的表达。含有AMPK显性阴性形式的腺病毒(Ad-dN-AMPK)和化合物G均可阻断二甲双胍诱导的SHP基因表达，并能抑制肝细胞核因子4α或FOXA2介导的PEPCK和G6Pase启动子活性，并被siRNA SHP阻断。此外，携带siRNA SHP的腺病毒敲除SHP可抑制二甲双胍对cAMP/地塞米松诱导的肝糖异生基因表达的抑制作用。此外，口服二甲双胍可增加B6-LEP(ob/ob)小鼠的SHP mRNA水平。Ad-SHP过表达SHP可降低B6-Lep(ob/ob)小鼠的血糖水平和肝糖异生基因的表达。结论二甲双胍通过AMPK依赖性调节SHP抑制肝糖异生。
OBJECTIVE-Metformin is an antidiabetic drug commonly used to treat type 2 diabetes. The aim of the study was to determine whether metformin regulates hepatic gluconeogenesis through the orphan nuclear receptor small heterodimer partner (SHP, NR0B2).RESEARCH DESIGN AND METHODS-We assessed the regulation of hepatic SHP gene expression by Northern blot analysis with metformin and adenovirus containing a constitutive active form of AMP-activated protein kinase (AMPK) (Ad-AMPK) and evaluated SHP, PEPCK, and G6Pase promoter activities via transient transfection assays in hepatocytes. Knockdown of SHP using siRNA SHP was conducted to characterize the metformin-induced inhibition of hepatic gluconeogenic gene expression in hepatocytes, and metformin- and adenovirus SHP (Ad-SHP) mediated hepatic glucose production was measured in B6-Lep (ob/ob) mice.RESULTS-Hepatic SHP gene expression was induced by metformin, 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR), and Ad-AMPK. Metformin-induced SHP gene expression was abolished by adenovirus containing the dominant negative form of AMPK (Ad-DN-AMPK), as well as by compound G. Metformin inhibited hepatocyte nuclear factor-4 alpha- or FoxA2-mediated promoter activity of PEPCK and G6Pase, and the inhibition was blocked with siRNA SHP. Additionally, SHP knockdown by adenovirus containing siRNA SHP inhibited metformin-mediated repression of cAMP/dexamethasone-induced hepatic gluconeogenic gene expression. Furthermore, oral administration of metformin increased SHP mRNA levels in B6-Lep (ob/ob) mice. Overexpression of SHP by Ad-SHP decreased blood glucose levels and hepatic gluconeogenic gene expression in B6-Lep(ob/ob) mice.CONCLUSIONS-We have concluded that metformin inhibits hepatic gluconeogenesis through AMPK-dependent regulation of SHP.