Abstract
Inflammatory reactions reduce the activity of cytochrome P450 isoforms. The aim of the study was to determine the mechanisms underlying the decrease in CYP1A2 and CYP3A6 catalytic activities produced by serum from rabbits with a turpentine-induced inflammatory reaction (STIIR) and interleukin 6 (IL-6). STIIR and IL-6 were incubated with cultured primary hepatocytes from control rabbits (HCONT), and from rabbits with a turpentine-induced inflammatory reaction (HTIIR) in the absence or presence of pyrrolidine dithiocarbamate (PDTC), an antioxidant and inhibitor of nuclear factor κB transcription; 2′-amino-3′-methoxyflavone (PD98059), an inhibitor of extracellular signal-related kinase (Erk1/2); 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole (SB203580), an inhibitor of p38MAPK; Nω-nitro-l-arginine methyl ester, an inhibitor of nitric-oxide synthase 2 (NOS2); the combination of PDTC, PD98059, and SB203580; and genistein, an inhibitor of Janus-associated protein tyrosine kinase (JAK). After 4 and 24 h of incubation of HCONT with STIIR and IL-6, CYP1A2 activity was reduced without changes in expression; the reduction in activity was partially prevented by the inhibition of JAK, Erk1/2, and NOS2. In HCONT, STIIR and IL-6 did not affect CYP3A6 activity; however, PDTC reduced CYP3A6 activity by 40 and 80% after 4 and 24 h of incubation. In HTIIR, STIIR and IL-6 reduced both CYP1A2 and CYP3A6 activities; this decrease is partially prevented by inhibitors of protein tyrosine kinases, Erk1/2, and NOS2. In HTIIR, SB203580 increased CYP3A6 activity in a dose-dependent manner without changes in protein expression. These results show that the signal transduction pathways mediating the decrease in CYP1A2 and 3A6 activity, produced by STIIR and IL-6, involve JAK, Erk1/2, and NOS2.
Footnotes
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This study was supported by the Canadian Institutes of Health Research (MOP-43925).
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Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
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doi:10.1124/dmd.105.006528.
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ABBREVIATIONS: P450, cytochrome P450; LPS, lipopolysaccharide; IL, interleukin; ROS, reactive oxygen species; NO·, nitric oxide; MAPK, mitogen-activated protein kinase; NOS, nitric-oxide synthase; NF-κB, nuclear factor κB; PD98059, 2′-amino-3′-methoxyflavone; SB203580, 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole; PDTC, pyrrolidine dithiocarbamate; SNP, sodium nitroprusside; PAGE, polyacrylamide gel electrophoresis; pTpY Erk1/2, phosphorylated Erk1/2; DFB, 3,4-difluorobenzyloxy-5,5 dimethyl-4-(4-methylsulfonyl phenyl)-(5H)-furan-2-one; DFH, 3-hydroxy-4-(4-methylsulfonyl phenyl)-(5H)-furan-2-one; Erk1/2, extracellular signal-related kinase 1/2; HCONT, hepatocytes from a control rabbit; HTIIR, hepatocytes from rabbits with a turpentine-induced inflammatory reaction; JAK, Janus-associated protein tyrosine kinase; l-NAME, Nω-nitro-l-arginine methyl ester; SCONT, serum from control rabbits; STIIR, serum from rabbits with a turpentine-induced inflammatory reaction; U74389G, 21-[4-(2,6-di-1-pyrrolidinyl-4-pyrimidinyl)-1-(piperazinyl]-pregna-1,4,9(11)-triene-3,20-dione (2)-2-butenedioate.
- Received July 12, 2005.
- Accepted September 29, 2005.
- The American Society for Pharmacology and Experimental Therapeutics
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