title: Eicosapentaenoic acid prevents endothelin-1-induced cardiomyocyte hypertrophy in vitro through the suppression of TGF-beta 1 and phosphorylated JNK.
abstract: The cardiovascular benefit of fish oil in humans and experimental animals has been reported. Endothelin (ET)-1 is a well-known cardiac hypertrophic factor. However, although many studies link a fish oil extract, eicosapentaenoic acid (EPA), to cardiac protection, the effects of EPA on cardiac hypertrophy and underlying mechanism(s) are unclear. The present study investigated whether EPA prevents ET-1-induced cardiomyocyte hypertrophy; the potential pathways likely to underlie such an effect were also investigated. Cardiomyocytes were isolated from neonatal rat heart, cultured for 3 days, and then treated for 24 h with vehicle only (control), treated with 0.1 nM ET-1 only, or pretreated with 10 microM EPA and then treated with 0.1 nM ET-1. The cells were harvested, and changes in cell surface area, protein synthesis, expression of a cytoskeletal (alpha-actinin) protein, and cell signaling were analyzed. ET-1 induced a 97% increase in cardiomyocyte surface area, a 72% increase in protein synthesis rate, and an increase in expression of alpha-actinin and signaling molecule [transforming growth factor-beta 1 (TGF-beta 1), c-Jun NH2-terminal kinase (JNK), and c-Jun]. Development of these ET-1-induced cellular changes was attenuated by EPA. Moreover, the hypertrophied cardiomyocytes showed a 1.5- and a 1.7-fold increase in mRNA expression of atrial and brain natriuretic peptides, the classical molecular markers of cardiac hypertrophy, respectively; these changes were also suppressed by EPA. Here we show that ET-1 induces cardiomyocyte hypertrophy and expression of hypertrophic markers, possibly mediated by JNK and TGF-beta 1 signaling pathways. These ET-1-induced effects were blocked by EPA, a major fish oil ingredient, suggesting that fish oil may have beneficial protective effects on cardiac hypertrophy.
authors.affiliation: Cardiovascular Division, Department of Internal Medicine, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan.
authors.forename: Nobutake
authors.initials: N
authors.lastname: Shimojo
authors.forename: Subrina
authors.initials: S
authors.lastname: Jesmin
authors.forename: Sohel
authors.initials: S
authors.lastname: Zaedi
authors.forename: Seiji
authors.initials: S
authors.lastname: Maeda
authors.forename: Masaaki
authors.initials: M
authors.lastname: Soma
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
authors.forename: Iwao
authors.initials: I
authors.lastname: Yamaguchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyauchi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D009320:Atrial Natriuretic Factor / Q000502:physiology; D015415:Biomarkers; D015153:Blotting, Western; D006332:Cardiomegaly / Q000139:chemically induced* / Q000473:pathology / Q000517:prevention & control*; D048429:Cell Size; D002478:Cells, Cultured; D015118:Eicosapentaenoic Acid / Q000494:pharmacology*; D019332:Endothelin-1 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000633:toxicity*; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*; D032383:Myocytes, Cardiac / Q000473:pathology*; D020097:Natriuretic Peptide, Brain / Q000502:physiology; D010766:Phosphorylation; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors*; D053773:Transforming Growth Factor beta1
chemical_list: D015415:Biomarkers; D019332:Endothelin-1; D012333:RNA, Messenger; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor; D015118:Eicosapentaenoic Acid; D048031:JNK Mitogen-Activated Protein Kinases