Activation of mitogen-activated protein kinase by hepatocyte growth factor is stimulated by both alpha1- and beta2-adrenergic agonists in primary cultures of adult rat hepatocytes.
We investigated the effects of alpha(1)- and beta(2)-adrenergic agonists on hepatocyte growth factor (HGF)-stimulated mitogen-activated protein kinase (MAPK) isoforms in primary cultures of adult rat hepatocytes. Hepatocytes were isolated and cultured with HGF (5 ng/ml) and/or alpha- and beta-adrenergic agonists. Phosphorylated MAPK isoforms (p42 and p44 MAPK) were detected by Western blotting analysis using anti-phospho-MAPK antibody. The results show that HGF increased phosphorylation of p42 MAPK by 2.2-fold within 3 min. The HGF-induced MAPK activation was abolished by AG1478 treatment (10(-7) M). The MEK (MAPK kinase) inhibitor PD98059 (10(-6) M) completely inhibited the HGF-dependent increase in MAPK activity. Phenylephrine (10(-6) M) and metaproterenol (10(-6) M) alone had no effect in the absence of HGF, but significantly increased p42 MAPK induction by HGF. Moreover, the cell-permeable cAMP analog, 8-bromo cAMP (10(-7) M), and phorbol 12-myristate 13 acetate (10(-7) M) potentiated HGF-induced MAPK phosphorylation. The effects of these analogs were antagonized by the protein kinase A (PKA) inhibitor H-89 (10(-7) M) and the protein kinase C (PKC) inhibitor sphingosine (10(-6) M), respectively. These results suggest that direct or indirect activation of both PKA and PKC represent a positive regulatory mechanism for stimulating MAPK induction by HGF.
Kimura
Mitsutoshi
M
Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Josai University, Keyakidai, Sakado, Saitama, Japan. mkimura@josai.ac.jp
Okamoto
Hiroshi
H
Ogihara
Masahiko
M
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000322:Adrenergic Agonists / Q000494:pharmacology*; D058646:Adrenergic alpha-1 Receptor Agonists; D058666:Adrenergic beta-2 Receptor Agonists; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008954:Models, Biological; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D011799:Quinazolines; D051381:Rats; D017208:Rats, Wistar; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000037:antagonists & inhibitors; D020123:Sirolimus / Q000494:pharmacology; D013110:Sphingosine / Q000494:pharmacology; D020032:Tyrphostins / Q000494:pharmacology; D000077191:Wortmannin
D000322:Adrenergic Agonists; D058646:Adrenergic alpha-1 Receptor Agonists; D058666:Adrenergic beta-2 Receptor Agonists; D000730:Androstadienes; D004791:Enzyme Inhibitors; D005419:Flavonoids; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011799:Quinazolines; D020032:Tyrphostins; C101044:RTKI cpd; D015124:8-Bromo Cyclic Adenosine Monophosphate; D017228:Hepatocyte Growth Factor; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D013110:Sphingosine; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D020123:Sirolimus; D000077191:Wortmannin