Tumor necrosis factor-alpha decreases pulmonary artery endothelial nitrovasodilator via protein kinase C.
We postulated that tumor necrosis factor-alpha (TNF) decreases endothelium-derived nitrovasodilator(s) via a protein kinase C (PKC)-dependent pathway. Calf pulmonary artery endothelial monolayers (PAEM) were treated with TNF (10, 100, and 1,000 U/ml) for 15 min or 18 h during an 18-h incubation. At the end of the incubation, the cell lysate and supernatant were harvested. Compared with controls, an 18-h incubation with TNF (100 and 1,000 U/ml) resulted in a decrease in NO2- [the oxidation product of nitric oxide (NO)] in PAEM lysate and supernatant. TNF (100 U/ml) treatment for 15 min did not suppress NO2- levels. The decrease in NO2- and the increase in lipid peroxides in response to TNF were prevented by pretreatment (15 min prior to and throughout the incubation) with either calphostin C (1 microM; a specific PKC inhibitor) or the antioxidants N-acetylcysteine (1 mM), 4,5-dihydroxy-1,3-benzene disulfonic acid (Tiron) (10 mM), and superoxide dismutase (10 U/ml). Treatment with phorbol 12-myristate 13-acetate (PMA, 1 microM for 15 min), an activator of PKC, decreased NO2- similarly to TNF. Pretreatment with calphostin C or N-acetylcysteine prior to TNF (10 U/ml) revealed an increase in NO2- levels above control treatment. Treatment with the NO synthase antagonists NG-monomethyl-L-arginine (1 mM) and N-nitroso-L-arginine (1 mM) induced an L-arginine (1 mM)-dependent decrease in NO2- in control but not in TNF-treated PAEM. The induction of NO2- by calcium ionophore (A23187; 500 nM) was not affected by treatment with TNF.(ABSTRACT TRUNCATED AT 250 WORDS)
Johnson
A
A
Research Service, Samuel S. Stratton Veterans Affairs Medical Center, Albany, New York.
Phelps
D T
DT
Ferro
T J
TJ
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002417:Cattle; D004730:Endothelium, Vascular / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D009574:Nitro Compounds / Q000037:antagonists & inhibitors*; D009603:Nitroso Compounds / Q000494:pharmacology; D010545:Peroxides / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D011651:Pulmonary Artery / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000037:antagonists & inhibitors*; D019323:omega-N-Methylarginine
D009573:Nitrites; D009574:Nitro Compounds; D009603:Nitroso Compounds; D010545:Peroxides; D014409:Tumor Necrosis Factor-alpha; D014665:Vasodilator Agents; C084185:N-nitrosoarginine; D019323:omega-N-Methylarginine; D000001:Calcimycin; D001120:Arginine; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate