title: The selective inhibition of nitric oxide production in the avian macrophage cell line HD11.
abstract: The production of reactive nitrogen, nitric oxide (NO), has previously been demonstrated to be a major mechanism by which the innate immune system defends against microbial invasion. The induction of many antimicrobial mechanisms is regulated by numerous components during the transduction of the signal from the cell surface to the cell nucleus where response genes are upregulated. Toll-like cell surface receptor activation often leads to sequential modulation of protein tyrosine kinases (PTK), mitogen activated protein kinases (MAPK), degradation of I kappa B (IkappaB) regulatory molecules which, in turn, release the nuclear factor-kappa B (NF-kappaB) family proteins for translocation into the nucleus and subsequent gene transcription. The purpose of this study was to investigate components of the upstream signal transduction pathway induced by bacterial and viral-like stimulation of NO for antimicrobial defense by the transformed chicken macrophage cell line, HD11. We quantified the production of nitrite by chicken macrophages after exposure to selective pharmacological inhibitors of specific signal transduction components prior to stimulation by polyinosinic polycytidylic acid (poly I:C), formalin-fixed Enterococcus gallinarum (EG) or formalin-fixed Klebsiella pneumoniae (KP). We found that NO production induced by dsRNA or bacteria was reduced in a dose dependent manner by specific inhibitors of PTK, p38 MAPK, IkappaB, and NF-kappaB. Inhibition efficacy varied dependent on stimulation by bacterial or viral-like ligands. In general, NO production induced by bacterial stimulation was most effectively reduced by inhibition of p38 MAPK and least effectively reduced by inhibition of IkappaB. NF-kappaB and IkappaB inhibition affected NO production induced by dsRNA more than that induced by bacterial stimulation.
authors.affiliation: Southern Plains Area Research Center, Agricultural Research Service, United States Department of Agriculture, 2881 FandB Road, College Station, TX 77845, USA. crippen@ffsru.tamu.edu
authors.forename: Tawni L
authors.initials: TL
authors.lastname: Crippen
mesh_terms: D000818:Animals; D002109:Caffeic Acids / Q000494:pharmacology; D002460:Cell Line; D002645:Chickens / Q000276:immunology* / Q000378:metabolism*; D016983:Enterococcus / Q000276:immunology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D020672:I-kappa B Proteins / Q000037:antagonists & inhibitors / Q000276:immunology; D007711:Klebsiella pneumoniae / Q000276:immunology; D007976:Leupeptins / Q000494:pharmacology; D008262:Macrophage Activation / Q000187:drug effects / Q000276:immunology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000276:immunology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000276:immunology; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives / Q000494:pharmacology; D011070:Poly I-C / Q000276:immunology; D011201:Poultry Diseases / Q000276:immunology / Q000382:microbiology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000276:immunology; D012330:RNA, Double-Stranded / Q000276:immunology; D015398:Signal Transduction; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000276:immunology
chemical_list: D002109:Caffeic Acids; D004791:Enzyme Inhibitors; D020672:I-kappa B Proteins; D007976:Leupeptins; D016328:NF-kappa B; D012330:RNA, Double-Stranded; C063261:acetylleucyl-leucyl-norleucinal; D009569:Nitric Oxide; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C055494:caffeic acid phenethyl ester; D010626:Phenylethyl Alcohol; D011070:Poly I-C