title: Activation of AMP-activated protein kinase enhances angiotensin ii-induced proliferation in cardiac fibroblasts.
abstract: AMP-activated kinase (AMPK) is a highly conserved heterotrimeric kinase that functions as a metabolic regulator of cellular enzymes involved in carbohydrate and fat metabolism, which regulate ATP conservation and synthesis. Here, we investigated whether AMPK signaling has a role in the regulation of angiotensin II (Ang II)-induced proliferation in rat cardiac fibroblasts. Aminoimidazole-4-carboxamide-1-beta-ribofuranoside (AICAR) activated AMPK in rat cardiac fibroblasts and increased Ang II-induced extracellular signal-regulated kinase 1/2 phosphorylation and activity. AICAR also increased Ang II-induced c-fos mRNA expression in the cells. [3H]-thymidine and [3H]-proline incorporation by cardiac fibroblasts treated with Ang II was enhanced when the cells were pretreated with AICAR. Inhibition of AMPK by small interfering RNA for AMPKalpha1 suppressed Ang II-induced extracellular signal-regulated kinase activity, c-fos mRNA expression, and cell proliferation. Treatment of rats with AICAR (1 mg/g body weight per day) for 1 week significantly enhanced Ang II-induced hypertrophy of the myocardium. Our findings indicate that AMPK works as a stimulator of the Ang II-induced proliferative pathway in cardiac fibroblasts. Inhibition of AMPK signaling might serve as a new therapeutic target of remodeling of the hypertrophic myocardium.
authors.affiliation: Department of Endocrinology and Metabolism, Dokkyo University School of Medicine, Mibu, Tochigi 321-0293, Japan. yhattori@dokkyomed.ac.jp
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Hattori
authors.forename: Kazumi
authors.initials: K
authors.lastname: Akimoto
authors.forename: Toshio
authors.initials: T
authors.lastname: Nishikimi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Matsuoka
authors.forename: Kikuo
authors.initials: K
authors.lastname: Kasai
mesh_terms: D055372:AMP-Activated Protein Kinases; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D006332:Cardiomegaly / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D004357:Drug Synergism; D004789:Enzyme Activation / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology* / Q000378:metabolism; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D009206:Myocardium / Q000166:cytology*; D009929:Organ Size / Q000187:drug effects; D011392:Proline / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012265:Ribonucleotides / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology; D013936:Thymidine / Q000378:metabolism
chemical_list: D009097:Multienzyme Complexes; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D012265:Ribonucleotides; D000804:Angiotensin II; D000620:Aminoimidazole Carboxamide; D011392:Proline; D017346:Protein Serine-Threonine Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D055372:AMP-Activated Protein Kinases; C031143:AICA ribonucleotide; D013936:Thymidine