title: Activation of mitogen-activated protein kinase pathways by cyclic GMP and cyclic GMP-dependent protein kinase in contractile vascular smooth muscle cells.
abstract: Vascular smooth muscle cells (VSMC) exist in either a contractile or a synthetic phenotype in vitro and in vivo. The molecular mechanisms regulating phenotypic modulation are unknown. Previous studies have suggested that the serine/threonine protein kinase mediator of nitric oxide (NO) and cyclic GMP (cGMP) signaling, the cGMP-dependent protein kinase (PKG) promotes modulation to the contractile phenotype in cultured rat aortic smooth muscle cells (RASMC). Because of the potential importance of the mitogen-activated protein kinase (MAP kinase) pathways in VSMC proliferation and phenotypic modulation, the effects of PKG expression in PKG-deficient and PKG-expressing adult RASMC on MAP kinases were examined. In PKG-expressing adult RASMC, 8-para-chlorophenylthio-cGMP activated extracellular signal- regulated kinases (ERK1/2) and c-Jun N-terminal kinase (JNK). The major effect of PKG activation was increased activation by MAP kinase kinase (MEK). The cAMP analog, 8-Br-cAMP inhibited ERK1/2 activation in PKG-deficient and PKG-expressing RASMC but had no effect on JNK activity. The effects of PKG on ERK and JNK activity were additive with those of platelet-derived growth factor (PDGF), suggesting that PKG activates MEK through a pathway not used by PDGF. The stimulatory effects of cGMP on ERK and JNK activation were also observed in low-passaged, contractile RASMC still expressing endogenous PKG, suggesting that the effects of PKG expression were not artifacts of cell transfections. These results suggest that in contractile adult RASMC, NO-cGMP signaling increases MAP kinase activity. Increased activation of these MAP kinase pathways may be one mechanism by which cGMP and PKG activation mediate c-fos induction and increased proliferation of contractile adult RASMC.
authors.affiliation: Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0019, USA. padmini@path.uab.edu
authors.forename: P
authors.initials: P
authors.lastname: Komalavilas
authors.forename: P K
authors.initials: PK
authors.lastname: Shah
authors.forename: H
authors.initials: H
authors.lastname: Jo
authors.forename: T M
authors.initials: TM
authors.lastname: Lincoln
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D001011:Aorta; D002227:Carbazoles; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology*; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression; D007211:Indoles / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D013873:Thionucleotides / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: C090860:8-(4-chlorophenylthio)guanosine 3',5'-cyclic monophosphorothioate; D000470:Alkaloids; D002227:Carbazoles; D004791:Enzyme Inhibitors; D007211:Indoles; D010982:Platelet-Derived Growth Factor; D011758:Pyrroles; D011993:Recombinant Fusion Proteins; D013873:Thionucleotides; D014409:Tumor Necrosis Factor-alpha; C073601:KT 5823; D015124:8-Bromo Cyclic Adenosine Monophosphate; C057416:KT 5720; D017346:Protein Serine-Threonine Kinases; D017869:Cyclic GMP-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020930:MAP Kinase Kinase Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; D006152:Cyclic GMP