The involvement of secondary signaling molecules in cytochrome P-450 1A1-mediated inducible nitric oxide synthase expression in benzo(a)pyrene-treated rat polymorphonuclear leukocytes.
Benzo(a)pyrene induces cytochrome P-450 1A1 (CYP1A1) expression in rat polymorphonuclear leukocytes (PMNs) that upregulates expression of inducible nitric oxide synthase (iNOS). In the present study, the involvement of secondary signaling molecules in CYP1A1-mediated augmentation of iNOS expression in benzo(a)pyrene-treated rat PMNs was investigated. PMNs were isolated from the peripheral blood of controls and benzo(a)pyrene-treated rats. The expression and/or activity of CYP1A1, iNOS, tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1beta), and intracellular calcium ([Ca(2+)]i) concentrations were measured in control and benzo(a)pyrene-treated rat PMNs with and without alpha-naphthoflavone, aminoguanidine, genistein, pyrrolidine dithiocarbamate (PDTC), felodipine, or SB202190 pre-treatment. A significant elevation in CYP1A1 and [Ca(2+)]i was observed in benzo(a)pyrene-treated rat PMNs, which was significantly restored by alpha-naphthoflavone or genistein. Neither PDTC, SB202190, nor aminoguanidine altered the benzo(a)pyrene-mediated increase in [Ca(2+)]i. Although felodipine reduced the benzo(a)pyrene-mediated increase in [Ca(2+)]i, no significant change was observed in CYP1A1 expression and activity. Benzo(a)pyrene-augmented iNOS expression and activity in PMNs were significantly reverse by felodipine, genistein, or PDTC. Benzo(a)pyrene also induced TNF-alpha and IL-1beta production in PMNs, which was significantly reversed by genistein. The results demonstrated the involvement of [Ca(2+)]i, tyrosine kinase, inflammatory cytokines, and NF-kappaB in CYP1A1-mediated iNOS expression in benzo(a)pyrene-treated rat PMNs.
Kumar
Abhai
A
Environmental Biotechnology Division, Industrial Toxicology Research Centre (ITRC), Lucknow-226 001, India.
Upadhyay
Ghanshyam
G
Modi
Dinesh Raj
DR
Singh
Mahendra Pratap
MP
D000818:Animals; D001564:Benzo(a)pyrene / Q000633:toxicity*; D002118:Calcium / Q000378:metabolism; D002384:Catalysis; D019363:Cytochrome P-450 CYP1A1 / Q000037:antagonists & inhibitors / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D053583:Interleukin-1beta / Q000032:analysis / Q000096:biosynthesis; D008297:Male; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology*; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D009573:Nitrites / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000096:biosynthesis
D004791:Enzyme Inhibitors; D053583:Interleukin-1beta; D009573:Nitrites; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D001564:Benzo(a)pyrene; D052247:Nitric Oxide Synthase Type II; D019363:Cytochrome P-450 CYP1A1; D002118:Calcium