title: Inhibition of superoxide anion generation by YC-1 in rat neutrophils through cyclic GMP-dependent and -independent mechanisms.
abstract: 3-(5'-Hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1), a soluble guanylyl cyclase (sGC) activator, inhibited formyl-methionyl-leucyl-phenylalanine (fMLP)-induced superoxide anion (O(2)*(-)) generation and O(2) consumption in rat neutrophils (IC(50) values of 12.7+/-3.1 and 17.7+/-6.9 microM, respectively). Inhibition of O(2)*(-) generation by YC-1 was partially reversed by the cyclic GMP-lowering agent 6-anilinoquinoline-5,8-quinone (LY83583) and by the Rp isomer of 8-(4-chlorophenylthio)guanosine-3',5'-monophosphorothioate (Rp-8-pCPT-cGMPS), a cyclic GMP-dependent protein kinase inhibitor. In cell-free systems, YC-1 failed to alter O(2)*(-) generation during dihydroxyfumaric acid autoxidation, phorbol 12-myristate 13-acetate (PMA)-activated neutrophil particulate NADPH oxidase preparation, and arachidonic acid-induced NADPH oxidase activation. YC-1 increased cellular cyclic GMP levels through the activation of sGC and the inhibition of cyclic GMP-hydrolyzing phosphodiesterase activity. The plateau phase, but not the initial spike, of fMLP-induced [Ca(2+)](i) changes was inhibited by YC-1 (IC(50) about 15 microM). fMLP- but not PMA-induced phospholipase D activation was inhibited by YC-1 (IC(50) about 28 microM). Membrane-associated ADP-ribosylation factor and Rho A in cell activation was also reduced by YC-1 at a similar concentration range. Neither cytosolic protein kinase C (PKC) activity nor PKC membrane translocation was altered by YC-1. YC-1 did not affect either fMLP-induced phosphatidylinositol 3-kinase activation or p38 mitogen-activated protein kinase phosphorylation, but slightly attenuated the phosphorylation of extracellular signal-regulated kinase. Collectively, these results indicate that the inhibition of the fMLP-induced respiratory burst by YC-1 is mediated by cyclic GMP-dependent and -independent signaling mechanisms.
authors: Department of Education and Research, Taichung Veterans General Hospital, 160 Chung Kang Road, Sec. 3, 407, ROC, Taichung, Taiwan. w1994@vghtc.gov.tw
authors: Jih Pyang
authors: JP
authors: Wang
authors: Ling Chu
authors: LC
authors: Chang
authors: Shue Ling
authors: SL
authors: Raung
authors: Mei Feng
authors: MF
authors: Hsu
authors: Li Jiau
authors: LJ
authors: Huang
authors: Sheng Chu
authors: SC
authors: Kuo
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002474:Cell-Free System / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism*; D020536:Enzyme Activators / Q000494:pharmacology; D066298:In Vitro Techniques; D007191:Indazoles / Q000494:pharmacology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D016897:Respiratory Burst / Q000187:drug effects; D013481:Superoxides / Q000378:metabolism*
chemical_list: D020536:Enzyme Activators; D007191:Indazoles; D013481:Superoxides; C090937:3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole; D019869:Phosphatidylinositol 3-Kinases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D010739:Phospholipase D; D006152:Cyclic GMP; D002118:Calcium