Basic fibroblast growth factor protects cardiac myocytes from iNOS-mediated apoptosis.
Basic fibroblast growth factor (bFGF) is an important angiogenic factor produced by hearts subjected to ischemia. However, the direct effects of bFGF on myocardial cells are unknown. Primary cultured cardiac myocytes from neonatal rats were stimulated with lipopolysaccharide (LPS), a potent inducer of inducible nitric oxide synthase (iNOS), in the presence or the absence of bFGF. LPS induced the expression of iNOS in cardiac myocytes, demonstrated at both mRNA and protein levels. We showed that LPS activated the apoptotic pathway, evidenced by TUNEL staining, DNA ladder formation, and morphologic features. LPS-induced apoptosis was blocked by the administration of L-NAME, an inhibitor of NOS. This indicates that LPS induces apoptosis via an iNOS-dependent pathway. Administration of bFGF completely inhibited myocardial cell apoptosis induced by hydrogen peroxide or acidic medium as well as LPS. To determine signaling pathways for this inhibitory effect, we utilized PD098059, an MEK-1-specific inhibitor. PD098059 blocked bFGF-induced activation of ERK (extracellularly responsive kinase)-1/2 and neutralized the apoptotic inhibitory effect of bFGF. These findings demonstrate that LPS induces myocardial cell apoptosis in an iNOS-dependent manner. The results also suggest that bFGF is a protective factor against myocardial cell apoptosis and that this protection requires the MEK-1-ERK pathway.
Iwai-Kanai
Eri
E
Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, 54 Kawara-cho, Shogoin Sakyo-ku, Kyoto 606-8507, Japan.
Hasegawa
Koji
K
Fujita
Masatoshi
M
Araki
Makoto
M
Yanazume
Tetsuhiko
T
Adachi
Souichi
S
Sasayama
Shigetake
S
D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D019610:Cytoprotection / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D020287:In Situ Nick-End Labeling; D008070:Lipopolysaccharides / Q000633:toxicity; D048369:MAP Kinase Kinase 1; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009206:Myocardium / Q000166:cytology / Q000201:enzymology*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
D004791:Enzyme Inhibitors; D005419:Flavonoids; D008070:Lipopolysaccharides; D016222:Fibroblast Growth Factor 2; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one