Smooth muscle cell expression of type I cyclic GMP-dependent protein kinase is suppressed by continuous exposure to nitrovasodilators, theophylline, cyclic GMP, and cyclic AMP.
A key component of the nitric oxide-cyclic guanosine monophosphate (cGMP) pathway in smooth muscle cells (SMC) is the type I GMP-dependent protein kinase (PK-G I). Activation of PK-G I mediates the reduction of cytoplasmic calcium concentrations and vasorelaxation. In this manuscript, we demonstrate that continuous exposure of SMC in culture to the nitrovasodilators S-nitroso-N-acetylpenicillamine (SNAP) or sodium nitroprusside (SNP) results in approximately 75% suppression of PK-G I mRNA by 48 h. PK-G I mRNA and protein were also suppressed by continuous exposure to cGMP analogues 8-bromo- and 8-(4-chlorophenylthio) guanosine-3,5-monophosphate or the cAMP analogue dibutyryl cAMP. These results suggest that activation of one or both of the cyclic nucleotide-dependent protein kinases mediates PK-G I mRNA suppression. Using isoform-specific cDNA probes, only the PK-G I alpha was detected in SMC, either at baseline or after suppression, while PK-G I beta was not detected, indicating that isoform switch was not contributing to the gene regulation. Using the transcription inhibitor actinomycin D, the PK-G I mRNA half-life in bovine SMC was observed to be 5 h. The half-life was not affected by the addition of SNAP to actinomycin D, indicating no effect on PK-G I mRNA stability. Nuclear runoff studies indicated a suppression of PK-G I gene transcription by SNAP. PK-G I suppression was also observed in vivo in rats given isosorbide dinitrate in the drinking water, with a dose-dependent suppression of PK-G I protein in the aorta. PK-G I antigen in whole rat lung extract was also suppressed by administration of isosorbide or theophylline in the drinking water. These data may contribute to our understanding of nitrovasodilator resistance, a phenomenon resulting from continuous exposure to nitroglycerin or other nitrovasodilators.
Soff
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GA
Department of Medicine, Northwestern University Medical School, Chicago, Illinois 60611, USA. gasoff@merle.acns.nwu.edu
Cornwell
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Cundiff
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Gately
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Lincoln
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D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000201:enzymology; D003994:Bucladesine / Q000494:pharmacology; D002417:Cattle; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D017869:Cyclic GMP-Dependent Protein Kinases / Q000096:biosynthesis*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D007547:Isosorbide / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology*; D009599:Nitroprusside / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D026423:S-Nitroso-N-Acetylpenicillamine; D013806:Theophylline / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D012333:RNA, Messenger; D013873:Thionucleotides; D014665:Vasodilator Agents; D009599:Nitroprusside; D005576:Colforsin; C016276:8-bromocyclic GMP; C055656:8-((4-chlorophenyl)thio)cyclic-3',5'-GMP; D003994:Bucladesine; D026423:S-Nitroso-N-Acetylpenicillamine; D013806:Theophylline; D000242:Cyclic AMP; D017869:Cyclic GMP-Dependent Protein Kinases; D010396:Penicillamine; D006152:Cyclic GMP; D007547:Isosorbide