Activation of AMPK inhibits cardiomyocyte hypertrophy by modulating of the FOXO1/MuRF1 signaling pathway in vitro  

作　　者：Bao-lin CHEN Yue-dong MA Rong-sen MENG Zhao-jun XIONG Hai-ning WANG Jun-yi ZENG Chen LIU Yu-gang DONG 

机构地区：[1]Department of Cardiology, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China [2]Department of Cardiology, the People's Hospital of Guizhou Province, Guiyang 550002, China [3]Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China

出　　处：《Acta Pharmacologica Sinica》2010年第7期798-804,共7页中国药理学报（英文版）

基　　金：Acknowledgements This study was supported by research grants from the National Natural Science Foundation of China （30770898 and 30971260） and the Natural Science Foundation of Guangdong Province （8251008901000013）.

摘　　要：Aim： To examine the inhibitory effects of adenosine monophosphate-activated protein kinase （AMPK） activation on cardiac hypertrophy in vitro and to investigate the underlying molecular mechanisms. Methods： Cultured neonatal rat cardiomyocytes were treated with the specific AMPK activator 5-aminoimidazole-4-carboxamide ribonucleoside （AICAR） and the specific AMPK antagonist Compound C, and then stimulated with phenylephrine （PE）. The Muscle RING finger 1 （MuRF1）-small interfering RNA （siRNA） was transfected into cardiomyocytes using Lipofectamine 2000. The surface area of cultured cardiomyocytes was measured using planimetry. The protein degradation was determined using high performance liquid chromatograPhY （HPLC）. The expression of β-myosin heavy chain （13-MHC） and MuRF1, as well as the phosphorylation levels of AMPK and Forkhead box O 1 （FOXO1）, were separately measured using Western blot or real-time polymerase chain reaction. Results： Activation of AMPK by AICAR 0.5 mmol/L inhibited PE-induced increase in cardiomyocyte area and β-MHC protein expression and PE-induced decrease in protein degradation. Furthermore, AMPK activation increased the activity of transcription factor FOXO1 and up-regulated downstream atrogene MuRF1 mRNA and protein expression. Treatment of hypertrophied cardiomyocytes with Compound C I pmol/L blunted the effects of AMPK on cardiomyocyte hypertrophy and changes to the FOXO1/MuRF1 pathway. The effects of AICAR on cardiomyocyte hypertrophy were also blocked after MuRF1 was silenced by transfection of cardiomyocytes with MuRF1- siRNA. Conclusion： The present study demonstrates that AMPK activation attenuates cardiomyocyte hypertrophy by modulating the atrophy- related FOXO1/MuRF1 signaling pathway in vitro.Aim： To examine the inhibitory effects of adenosine monophosphate-activated protein kinase （AMPK） activation on cardiac hypertrophy in vitro and to investigate the underlying molecular mechanisms. Methods： Cultured neonatal rat cardiomyocytes were treated with the specific AMPK activator 5-aminoimidazole-4-carboxamide ribonucleoside （AICAR） and the specific AMPK antagonist Compound C, and then stimulated with phenylephrine （PE）. The Muscle RING finger 1 （MuRF1）-small interfering RNA （siRNA） was transfected into cardiomyocytes using Lipofectamine 2000. The surface area of cultured cardiomyocytes was measured using planimetry. The protein degradation was determined using high performance liquid chromatograPhY （HPLC）. The expression of β-myosin heavy chain （13-MHC） and MuRF1, as well as the phosphorylation levels of AMPK and Forkhead box O 1 （FOXO1）, were separately measured using Western blot or real-time polymerase chain reaction. Results： Activation of AMPK by AICAR 0.5 mmol/L inhibited PE-induced increase in cardiomyocyte area and β-MHC protein expression and PE-induced decrease in protein degradation. Furthermore, AMPK activation increased the activity of transcription factor FOXO1 and up-regulated downstream atrogene MuRF1 mRNA and protein expression. Treatment of hypertrophied cardiomyocytes with Compound C I pmol/L blunted the effects of AMPK on cardiomyocyte hypertrophy and changes to the FOXO1/MuRF1 pathway. The effects of AICAR on cardiomyocyte hypertrophy were also blocked after MuRF1 was silenced by transfection of cardiomyocytes with MuRF1- siRNA. Conclusion： The present study demonstrates that AMPK activation attenuates cardiomyocyte hypertrophy by modulating the atrophy- related FOXO1/MuRF1 signaling pathway in vitro.

关 键 词：monophosphate-activated protein kinase （AMPK） Forkhead box 01 （FOX01） cardiac hypertrophy MuRF1 ubiquitin-proteasome system RNA interference 5-aminoimidazole-4-carboxamide ribonucleoside （AICAR） PHENYLEPHRINE 

分 类 号：Q463[生物学—生理学] S831.1[农业科学—畜牧学]