AMPK phosphorylates and inhibits SREBP activity to attenuate hepatic steatosis and atherosclerosis in diet-induced insulin-resistant mice.

Abstract

AMPK has emerged as a critical mechanism for salutary effects of polyphenols on lipid metabolic disorders in type 1 and type 2 diabetes. Here we demonstrate that AMPK interacts with and directly phosphorylates sterol regulatory element binding proteins (SREBP-1c and -2). Ser372 phosphorylation of SREBP-1c by AMPK is necessary for inhibition of proteolytic processing and transcriptional activity of SREBP-1c in response to polyphenols and metformin. AMPK stimulates Ser372 phosphorylation, suppresses SREBP-1c cleavage and nuclear translocation, and represses SREBP-1c target gene expression in hepatocytes exposed to high glucose, leading to reduced lipogenesis and lipid accumulation. Hepatic activation of AMPK by the synthetic polyphenol S17834 protects against hepatic steatosis, hyperlipidemia, and accelerated atherosclerosis in diet-induced insulin-resistant LDL receptor-deficient mice in part through phosphorylation of SREBP-1c Ser372 and suppression of SREBP-1c- and -2-dependent lipogenesis. AMPK-dependent phosphorylation of SREBP may offer therapeutic strategies to combat insulin resistance, dyslipidemia, and atherosclerosis.

• Authors: Yu Li, Shanqin Xu, Maria M Mihaylova, Bin Zheng, Xiuyun Hou, Bingbing Jiang, Ogyi Park, Zhijun Luo, Etienne Lefai, John Y-J Shyy, Bin Gao, Michel Wierzbicki, Tony J Verbeuren, Reuben J Shaw, Richard A Cohen, Mengwei Zang
• Journal: Cell metabolism (Cell Metab) Vol. 13 Issue 4 Pg. 376-388 (Apr 06 2011) ISSN: 1932-7420 [Electronic] United States
• PMID: 21459323 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 Elsevier Inc. All rights reserved.

Chemical References

• 6,8-diallyl 5,7-dihydroxy 2-(2-allyl 3-hydroxy 4-methoxyphenyl)1-H benzo(b)pyran-4-one
• Benzopyrans
• Dietary Fats
• Receptors, LDL
• Sterol Regulatory Element Binding Protein 1
• Sterol Regulatory Element Binding Protein 2
• Metformin
• AMP-Activated Protein Kinases

Topics

• AMP-Activated Protein Kinases (metabolism)
• Animals
• Atherosclerosis (drug therapy)
• Benzopyrans (therapeutic use)
• Dietary Fats (pharmacology)
• Disease Models, Animal
• Fatty Liver (drug therapy)
• Humans
• Insulin Resistance
• Lipogenesis
• Male
• Metformin (therapeutic use)
• Mice
• Phosphorylation
• Receptors, LDL (genetics, metabolism)
• Sterol Regulatory Element Binding Protein 1 (antagonists & inhibitors, genetics, metabolism)
• Sterol Regulatory Element Binding Protein 2 (antagonists & inhibitors, genetics, metabolism)
• Transcription, Genetic