ATF-1 mediates protease-activated receptor-1 but not receptor tyrosine kinase-induced DNA synthesis in vascular smooth muscle cells.
Previously we have demonstrated that activation of p38 mitogen-activated protein kinase (MAPK) and induction of DNA synthesis in response to receptor tyrosine kinase (RTK) and G protein-coupled receptor (GPCR) agonists require NADH/NADPH-like oxidase activity in vascular smooth muscle cells (VSMC). Here we tested the role of p38 MAPK in RTK and GPCR agonist-induced DNA synthesis in VSMC. Platelet-derived growth factor (PDGF)-BB and thrombin (RTK and GPCR agonists, respectively) activated p38 MAPK in a time-dependent manner in VSMC. Inhibition of p38 MAPK led to a 50% decrease in the DNA synthesis induced by thrombin but not PDGF-BB. ATF-1 was found to be the predominant member of the cyclic AMP response element (CRE)-DNA complex formed in VSMC in response to PDGF-BB and thrombin, and both agonists induced its phosphorylation. Regardless of this, inhibition of p38 MAPK reduced only thrombin- but not PDGF-BB-induced ATF-1 phosphorylation. Similarly, inhibition of p38 MAPK caused a 50% decrease in thrombin- but not PDGF-BB-induced CRE promoter-dependent transcription. Ectopic expression of an inhibitory anti-ATF-1 single-chain antibody fragment, ScFv, significantly interfered with DNA synthesis induced by thrombin but not PDGF-BB. Together, these results suggest the following conclusions. 1) Both RTK and GPCR agonists activate p38 MAPK and induce CRE promoter-dependent transcription; 2) both RTK and GPCR agonists induce ATF-1 phosphorylation, and ATF-1 is a predominant member in the CRE-DNA complexes formed in response to these agents; and 3) p38 MAPK-dependent ATF-1 phosphorylation and CRE promoter-mediated transcription are associated with GPCR agonist-induced VSMC growth.
Ghosh
Salil K
SK
Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA.
Gadiparthi
Laxmisilpa
L
Zeng
Zhao-Zhu
ZZ
Bhanoori
Manjula
M
Tellez
Carmen
C
Bar-Eli
Menashe
M
Rao
Gadiparthi N
GN
D051697:Activating Transcription Factor 1; D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology; D000077214:Becaplermin; D015153:Blotting, Western; D002455:Cell Division; D002701:Chloramphenicol / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis* / Q000378:metabolism; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017930:Genes, Reporter; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D020574:Proto-Oncogene Proteins c-sis; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin / Q000378:metabolism*; D013917:Thrombin / Q000378:metabolism / Q000494:pharmacology; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases
D051697:Activating Transcription Factor 1; D000925:Anticoagulants; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007093:Imidazoles; D010982:Platelet-Derived Growth Factor; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D020574:Proto-Oncogene Proteins c-sis; D011725:Pyridines; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin; D014157:Transcription Factors; D000077214:Becaplermin; D002701:Chloramphenicol; D004247:DNA; D011505:Protein-Tyrosine Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D013917:Thrombin; C093642:SB 203580