Stimulation by endothelin-1 of mitogen-activated protein kinases and DNA synthesis in bovine tracheal smooth muscle cells.
1. In cultures of bovine tracheal smooth muscle cells, platelet-derived growth factor-BB (PDGF), bradykinin (BK) and endothelin-1 (ET-1) stimulated the tyrosine phosphorylation and activation of both pp42 and pp44 kDa forms of mitogen-activated protein (MAP) kinase. 2. Both ET-1 and PDGF stimulated a sustained activation of MAP kinase whilst the response to BK was transient. 3. Activation of MAP kinase occurred in a concentration-dependent manner (EC50 values: ET-1, 2.3 +/- 1.3 nM; BK, 8.7 +/- 4.1 nM, PDGF, 9.7 +/- 3.2 ng ml-1). 4. Pretreatment with the protein kinase C (PKC) inhibitor Ro-318220, significantly reduced ET-1 activation of MAP kinase at 2 and 5 min but enhanced MAP kinase activation at 60 min. 5. Following chronic phorbol ester pretreatment, BK-stimulated activation of MAP kinase was abolished whilst the responses to PDGF and ET-1 were only partly reduced (80 and 45% inhibition respectively). 6. Pretreatment with pertussis toxin reduced ET-1 stimulated activation of MAP kinase particularly at later times (60 min), but left the responses to both PDGF and BK unaffected. 7. ET-1 also stimulated a 3 fold increase in [3H]-thymidine incorporation which was abolished by pertussis toxin pretreatment. In contrast, PDGF stimulated a 131 fold increase in [3H]-thymidine incorporation which was not affected by pertussis toxin. 8. These results suggest that a pertussis toxin-sensitive activation of MAP kinase may play an important role in ET-1-stimulated DNA synthesis but that activation of MAP kinase alone is not sufficient to induce the magnitude of DNA synthesis observed in response to PDGF.
Malarkey
K
K
Department of Physiology & Pharmacology, University of Strathclyde, Royal College, Glasgow.
Chilvers
E R
ER
Lawson
M F
MF
Plevin
R
R
D000818:Animals; D000077214:Becaplermin; D001920:Bradykinin / Q000378:metabolism / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000819:agonists / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis*; D016232:Endothelins / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D015151:Immunoblotting; D007295:Inositol Phosphates / Q000378:metabolism; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D037342:Pertussis Toxin; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D020574:Proto-Oncogene Proteins c-sis; D013268:Stimulation, Chemical; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism; D014132:Trachea / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D016232:Endothelins; D007295:Inositol Phosphates; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D010566:Virulence Factors, Bordetella; D000077214:Becaplermin; D004247:DNA; D037342:Pertussis Toxin; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D013755:Tetradecanoylphorbol Acetate; D001920:Bradykinin; D013936:Thymidine