RhoA expression is controlled by nitric oxide through cGMP-dependent protein kinase activation.
The small G protein RhoA is a convergence point for multiple signals that regulate smooth muscle cell functions. NO plays a major role in the structure and function of the normal adult vessel wall, mainly through modulation of gene transcription. This study was thus performed to analyze in vitro and in vivo the effect of NO signaling on RhoA expression in arterial smooth muscle cells. In rat or human artery smooth muscle cells, sodium nitroprusside or 8-(2-chlorophenylthio)-cGMP induced a rise in RhoA mRNA and protein expression, which was inhibited by the cGMP-dependent protein kinase (PKG) inhibitor (R(p))-8-bromo-beta-phenyl-1,N(2)-ethenoguanosine 3':5'-phosphorothioate. The NO/PKG stimulation of RhoA expression involved both an increase in RhoA protein stability and stimulation of rhoA gene transcription. Cloning and functional analysis of the human rhoA promoter revealed that the effect of NO/PKG involved phosphorylation of ATF-1 and subsequent binding to the cAMP-response element. Chronic inhibition of NO synthesis in N(omega)-nitro-l-arginine-treated rats induced a strong decrease in RhoA mRNA and protein expression in aorta and pulmonary artery associated with inhibition of RhoA-mediated Ca(2+) sensitization. These effects were prevented by oral administration of the cGMP phosphodiesterase inhibitor sildenafil. These results show that NO/PKG signaling positively controls RhoA expression and suggest that the basal release of NO is necessary to maintain RhoA expression and RhoA-dependent functions in vascular smooth muscle cells.
Sauzeau
Vincent
V
INSERM U-533, Faculté des Sciences, 44322 Nantes Cedex 3, France.
Rolli-Derkinderen
Malvyne
M
Marionneau
Céline
C
Loirand
Gervaise
G
Pacaud
Pierre
P
D016475:3T3 Cells; D000818:Animals; D001011:Aorta / Q000378:metabolism; D001158:Arteries / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000378:metabolism; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D051379:Mice; D016297:Mutagenesis, Site-Directed; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013873:Thionucleotides / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection; D020742:rhoA GTP-Binding Protein / Q000737:chemistry*
D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D013873:Thionucleotides; D009569:Nitric Oxide; C055656:8-((4-chlorophenyl)thio)cyclic-3',5'-GMP; D003513:Cycloheximide; D017869:Cyclic GMP-Dependent Protein Kinases; D020742:rhoA GTP-Binding Protein; D006152:Cyclic GMP