Inhibition of proinflammatory tumor necrosis factor-{alpha}-induced inducible nitric-oxide synthase by xanthine-based 7-[2-[4-(2-chlorobenzene)piperazinyl]ethyl]-1,3-dimethylxanthine (KMUP-1) and 7-[2-[4-(4-nitrobenzene)piperazinyl]ethyl]-1, 3-dimethylxanthine (KMUP-3) in rat trachea: The involvement of soluble guanylate cyclase and protein kinase G.
In the study of anti-proinflammation by 7-[2-[4-(2-chlorobenzene)piperazinyl] ethyl]-1,3-dimethylxanthine (KMUP-1) and 7-[2-[4-(4-nitrobenzene)piperazinyl]ethyl]-1,3-dimethylxanthine (KMUP-3), exposure of rat tracheal smooth muscle cells (TSMCs) to tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, increased the expression of inducible nitric-oxide synthase (iNOS) and NO production and decreased the expression of soluble guanylate cyclase alpha1 (sGCalpha1), soluble guanylate cyclase beta1 (sGCbeta1), protein kinase G (PKG), and the release of cGMP in TSMCs. The cell-permeable cGMP analog 8-Br-cGMP, xanthine-based KMUP-1 and KMUP-3, and the phosphodiesterase 5 inhibitor zaprinast all inhibited TNF-alpha-induced increases of iNOS expression and NO levels and reversed TNF-alpha-induced decreases of sGCalpha1, sGCbeta1, and PKG expression. These results imply that cGMP enhancers could have anti-proinflammatory potential in TSMCs. TNF-alpha also increased protein kinase A (PKA) expression and cAMP levels, cyclooxygenase-2 (COX-2) expression, and activated productions of prostaglandin (PG) E2 and 6-keto-PGF1alpha (stable PGI2 metabolite). Dexamethasone and N-[2-(cyclohexyloxyl)-4-nitrophenyl]-methane sulfonamide (NS-398; a selective COX-2 inhibitor) attenuated TNF-alpha-induced expression of COX-2 and activated productions PGE2 and PGI2. However, KMUP-1 and KMUP-3 did not affect COX-2 activities and did not further enhance cAMP levels in the presence of TNF-alpha. It is suggested that TNF-alpha-induced increases of PKA expression and cAMP levels are mediated by releasing PGE2 and PGI2, the activation products of COX-2. In conclusion, xanthine-based KMUP-1 and KMUP-3 inhibit TNF-alpha-induced expression of iNOS in TSMCs, involving the sGC/cGMP/PKG expression pathway but without the involvement of COX-2.
Wu
Bin-Nan
BN
Department and Graduate Institute of Pharmacology, College of Medicine, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan.
Chen
Chien-Wen
CW
Liou
Shu-Fen
SF
Yeh
Jwu-Lai
JL
Chung
Hui-Hsuan
HH
Chen
Ing-Jun
IJ
D000818:Animals; D002478:Cells, Cultured; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000378:metabolism; D006162:Guanylate Cyclase / Q000378:metabolism*; D007249:Inflammation; D008297:Male; D008954:Models, Biological; D032389:Myocytes, Smooth Muscle / Q000187:drug effects; D009566:Nitrates / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D009712:Nucleotides, Cyclic / Q000378:metabolism; D010880:Piperidines / Q000737:chemistry / Q000494:pharmacology*; D011453:Prostaglandins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012995:Solubility; D014132:Trachea / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014970:Xanthines / Q000737:chemistry / Q000494:pharmacology*
C508169:7-(2-(4-(4-nitrobenzene)piperazinyl)ethyl)-1,3-dimethylxanthine; D009566:Nitrates; D009573:Nitrites; D009712:Nucleotides, Cyclic; D010880:Piperidines; D011453:Prostaglandins; D014409:Tumor Necrosis Factor-alpha; D014970:Xanthines; C439304:KMUP 1; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D051546:Cyclooxygenase 2; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases; D017869:Cyclic GMP-Dependent Protein Kinases; D006162:Guanylate Cyclase