Document Detail

Prolonged AMPK activation increases the expression of fatty acid transporters in cardiac myocytes and perfused hearts.
MedLine Citation:
PMID:  16710744     Owner:  NLM     Status:  MEDLINE    
Recently, fatty acid transport across the plasma membrane has been shown to be a key process that contributes to the regulation of fatty acid metabolism in the heart. Since AMP kinase activation by 5-aminoimidazole-4-carboxamide-1-beta-D: -ribofuranoside (AICAR) stimulates fatty acid oxidation, as well as the expression of selected proteins involved with energy provision, we examined (a) whether AICAR induced the expression of the fatty acid transporters FABPpm and FAT/CD36 in cardiac myocytes and in perfused hearts and (b) the signaling pathway involved. Incubation of cardiac myocytes with AICAR increased the protein expression of the fatty acid transporter FABPpm after 90 min (+27%, P < 0.05) and this protein remained stably overexpressed until 180 min. Similarly, FAT/CD36 protein expression was increased after 60 min (+38%, P < 0.05) and remained overexpressed thereafter. Protein overexpression, which occurred via transcriptional mechanisms, was dependent on the AICAR concentration, with optimal induction occurring at AICAR concentrations 1-5 mM for FABPpm and at 2-8 mM for FAT/CD36. The AICAR (2 h, 2 mM AICAR) effects on FABPpm and FAT/CD36 protein expression were similar in perfused hearts and in cardiac myocytes. AICAR also induced the plasmalemmal content of FAT/CD36 (+49%) and FABPpm (+42%) (P < 0.05). This was accompanied by a marked increase in the rate of palmitate transport (2.5 fold) into giant sarcolemmal vesicles, as well as by increased rates of palmitate oxidation in cardiac myocytes. When the AICAR-induced AMPK phosphorylation was blocked, neither FAT/CD36 nor FABPpm were overexpressed, nor were palmitate uptake and oxidation increased. This study has revealed that AMPK activation stimulates the protein expression of both fatty acid transporters, FAT/CD36 and FABPpm in (a) time- and (b) dose-dependent manner via (c) the AMPK signaling pathway. AICAR also (d) increased the plasmalemmal content of FAT/CD36 and FABPm, thereby (e) increasing the rates of fatty acid transport. Thus, activation of AMPK is a key mechanism regulating the expression as well as the plasmalemmal localization of fatty acid transporters.
Adrian Chabowski; Iman Momken; Susan L M Coort; Jorge Calles-Escandon; Narendra N Tandon; Jan F C Glatz; Joost J F P Luiken; Arend Bonen
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-05-19
Journal Detail:
Title:  Molecular and cellular biochemistry     Volume:  288     ISSN:  0300-8177     ISO Abbreviation:  Mol. Cell. Biochem.     Publication Date:  2006 Aug 
Date Detail:
Created Date:  2006-08-31     Completed Date:  2007-01-10     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0364456     Medline TA:  Mol Cell Biochem     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  201-12     Citation Subset:  IM    
Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
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MeSH Terms
AMP-Activated Protein Kinases
Aminoimidazole Carboxamide / analogs & derivatives,  pharmacology
Antigens, CD36 / metabolism*
Dose-Response Relationship, Drug
Fatty Acid-Binding Proteins / metabolism*
Fatty Acids / metabolism
Hypoglycemic Agents / pharmacology
Multienzyme Complexes / metabolism*
Myocardium / enzymology,  metabolism*
Myocytes, Cardiac / drug effects,  enzymology,  metabolism*
Protein-Serine-Threonine Kinases / metabolism*
Rats, Wistar
Ribonucleotides / pharmacology
Signal Transduction
Reg. No./Substance:
0/Antigens, CD36; 0/FABPpm protein, rat; 0/Fatty Acid-Binding Proteins; 0/Fatty Acids; 0/Hypoglycemic Agents; 0/Multienzyme Complexes; 0/Ribonucleotides; 3031-94-5/AICA ribonucleotide; 360-97-4/Aminoimidazole Carboxamide; EC Protein Kinases; EC Kinases

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