title: Sodium nitroprusside augments human lung fibroblast collagen gel contraction independently of NO-cGMP pathway.
abstract: Nitric oxide (NO) relaxes vascular smooth muscle in part through an accumulation of cGMP in the target cells. We hypothesized that a similar effect may also exist on collagen gel contraction mediated by human fetal lung (HFL1) fibroblasts, a model of wound contraction. To evaluate this, HFL1 cells were cultured in three-dimensional type I collagen gels and floated in serum-free DMEM with and without various NO donors. Gel size was measured with an image analyzer. Sodium nitroprusside (SNP, 100 microM) significantly augmented collagen gel contraction by HFL1 cells (78.5 +/- 0.8 vs. 58.3 +/- 2. 1, P < 0.01), whereas S-nitroso-N-acetylpenicillamine, 5-amino-3-(4-morpholinyl)-1,2,3-oxadiazolium chloride, NONOate, and N(G)-monomethyl-L-arginine did not affect the contraction. Sodium ferricyanide, sodium nitrate, or sodium nitrite was not active. The augmentory effect of SNP could not be blocked by 1H-[1,2, 4]-oxadiazolo-[4,3-a]-quinoxalin-1-one, whereas it was partially reversed by 8-(4-chlorophenylthio) (CPT)-cGMP. To further explore the mechanisms by which SNP acted, fibronectin and PGE(2) production were measured by immunoassay after 2 days of gel contraction. SNP inhibited PGE(2) production and increased fibronectin production by HFL1 cells in a concentration-dependent manner. CPT-cGMP had opposite effects on fibronectin and PGE(2) production. Addition of exogenous PGE(2) blocked SNP-augmented contraction and fibronectin production by HFL1 cells. Therefore, SNP was able to augment human lung fibroblast-mediated collagen gel contraction, an effect that appears to be independent of NO production and not mediated through cGMP. Decreased PGE(2) production and augmented fibronectin production may have a role in this effect. These data suggest that human lung fibroblasts in three-dimensional type I collagen gels respond distinctly to SNP by mechanisms unrelated to the NO-cGMP pathway.
authors.affiliation: Pulmonary and Critical Care Medicine Section, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198-5300, USA.
authors.forename: X D
authors.initials: XD
authors.lastname: Liu
authors.forename: C M
authors.initials: CM
authors.lastname: Skold
authors.forename: T
authors.initials: T
authors.lastname: Umino
authors.forename: J R
authors.initials: JR
authors.lastname: Spurzem
authors.forename: D J
authors.initials: DJ
authors.lastname: Romberger
authors.forename: S I
authors.initials: SI
authors.lastname: Rennard
mesh_terms: D000818:Animals; D002460:Cell Line; D003094:Collagen / Q000378:metabolism*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D015232:Dinoprostone / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005333:Fetus / Q000166:cytology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D005782:Gels; D006801:Humans; D008168:Lung / Q000166:cytology*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology*; D009603:Nitroso Compounds / Q000494:pharmacology; D010069:Oxadiazoles / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D013873:Thionucleotides / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D004791:Enzyme Inhibitors; D005353:Fibronectins; D005782:Gels; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D010069:Oxadiazoles; D010975:Platelet Aggregation Inhibitors; D011810:Quinoxalines; C110881:S-nitro-N-acetylpenicillamine; D013873:Thionucleotides; D014665:Vasodilator Agents; C094210:2,2'-(hydroxynitrosohydrazono)bis-ethanamine; D009599:Nitroprusside; D009569:Nitric Oxide; C055656:8-((4-chlorophenyl)thio)cyclic-3',5'-GMP; D003094:Collagen; D010396:Penicillamine; D006152:Cyclic GMP; D015232:Dinoprostone