Regulation of cGMP-dependent protein kinase expression by soluble guanylyl cyclase in vascular smooth muscle cells.
Vascular smooth muscle cells (VSMC) undergo many phenotypic changes when placed in culture. Several studies have shown that the levels of expression of soluble guanylyl cyclase (sGC) or cGMP-dependent protein kinase (PKG) are altered in cultured VSMC. In this study the mechanisms involved in the coordinated expression of sGC and PKG were examined. Pro-inflammatory cytokines that increase the expression of type II NO synthase (inducible NO synthase, or iNOS) decreased PKG expression in freshly isolated, non-passaged bovine aortic SMC. However, in several passaged VSMC lines (i.e. bovine aortic SMC, human aortic SMC, and A7r5 cells), PKG protein expression was not suppressed by cytokines or NO. sGC was highly expressed in non-passaged bovine aortic SMC but not in passaged cell lines. Restoration of expression of sGC to passaged bovine SMC using adenovirus encoding the alpha1 and beta1 subunits of sGC restored the capacity of the cells to increase cGMP in response to NO. Furthermore, treatment of these sGC-transduced cells with NO donors for 48 h resulted in decreased PKG protein expression. In contrast, passaged rat aortic SMC expressed high levels of NO-responsive sGC but demonstrated reduced expression of PKG. Adenovirus-mediated expression of the PKG catalytically active domain in rat aortic SMC caused a reduction in the expression of sGC in these cells. These results suggest that there is a mechanism for the coordinated expression of sGC and PKG in VSMC and that prolonged activation of sGC down-regulates PKG expression. Likewise, the loss of PKG expression appears to increase sGC expression. These effects may be an adaptive mechanism allowing growth and survival of VSMC in vitro.
Browner
Natasha C
NC
Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
Dey
Nupur B
NB
Bloch
Kenneth D
KD
Lincoln
Thomas M
TM
D000256:Adenoviridae / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002417:Cattle; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000096:biosynthesis*; D016207:Cytokines / Q000096:biosynthesis / Q000378:metabolism; D005786:Gene Expression Regulation; D006162:Guanylate Cyclase / Q000378:metabolism*; D007249:Inflammation; D008070:Lipopolysaccharides / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D010641:Phenotype; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D015398:Signal Transduction; D013997:Time Factors
D016207:Cytokines; D008070:Lipopolysaccharides; D020030:Nitric Oxide Donors; D009569:Nitric Oxide; D012313:RNA; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D017869:Cyclic GMP-Dependent Protein Kinases; D006162:Guanylate Cyclase; D006152:Cyclic GMP