Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.5.1.19 (NOS)
 7,285 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activity of inducible nitric oxide synthase (iNOS) enzyme was quantified in chicken macrophages. Macrophages from Cornell K-strain (B15B15), GB1 (B13B13), and GB2 (B6B6) chickens and a transformed cell line (MQ-NCSU) were incubated with or without varying concentrations of bacterial lipopolysaccharide (LPS). The culture supernatants were tested for the presence of nitrite. Macrophages from either source produced minimal nitrite (< 4.4 microM/1 x 10(6) cells) levels without LPS stimulation. However, nitrite levels produced by K-strain (42 microM) and MQ-NCSU (41 microM) macrophages were higher (P < 0.05) than those produced by the GB1 (14 microM) and GB2 (14 microM) per 1 x 10(6) macrophages with optimum LPS concentration range of 50 ng to 1 microgram/mL. The addition of an L-arginine analog, NGMMLA, at a concentration of 200 microM completely abolished nitrite production. The addition of 10% vol/vol lymphokines exhibited an additive effect on nitrite production in conjunction with LPS. The increased nitrite production by the K-strain and MQ-NCSU macrophages corresponded to an increased expression of iNOS mRNA as compared to the mRNA produced by GB1 and GB2 macrophages. The iNOS mRNA kinetics study revealed that mRNA levels peaked between 6 to 12 h. The cells from avian lymphoid lineage failed to produce any detectable iNOS activity. These studies showed that macrophages from varying sources differ in NOS activity and implied that genetic background may dictate the extent of arginine-mediated contribution in various biological and immunological functions.
 ...
PMID:Nitric oxide synthase activity and mRNA expression in chicken macrophages. 935 46

Macrophages from Cornell K-strain chickens (B(15)B(15)) are hyper and from GB2 chickens (B(6)B(6)) are hypo-responders to LPS-mediated inducible NOS (iNOS) expression and activity. The molecular mechanism(s) responsible for this differential expression is not yet fully understood. We have previously reported that macrophages from K (iNOS hyper-responder) and GB2 (iNOS hypo-responder) chickens differ in constitutive expression of TLR4 but not in CD14 molecules. The objectives of the current study was to determine if the iNOS differences between K and GB2 macrophages are possibly due to differential expression of LPS-induced TLR4, CD14 and/or nuclear factor kappa B (NF kappa B). The results showed that Sephadex-elicited, adherence purified K macrophages expressed more inducible TLR4 and CD14 receptors (P<0.05) at 6 and 12h post-LPS stimulation than GB2 macrophages as measured by flow cytometry. In addition, pre-incubation of macrophages from a transformed chicken macrophage cell line, MQ-NCSU, with 50 microg/ml anti-CD14 and anti-TLR4 antibodies significantly reduced where as pre-incubation with 100 microg/ml completely blocked LPS-mediated iNOS activity as measured by nitrite levels. Furthermore, the amount of nuclear bound NF kappa B was found to be significantly greater in K than in GB2 macrophages at 3 min post-LPS stimulation. This nuclear localization of NF kappa B as well as iNOS activity was completely inhibited by pretreatment of macrophages with 50 micro M MG132, a proteosome inhibitor, both in K and GB2 macrophages. Taken together, these findings suggest that a differential and perhaps more stronger LPS-mediated signaling via CD14, TLR4 and NF kappa B is responsible for the heightened iNOS gene induction in K-strain (hyper-responder) macrophages than in GB2 (hypo-responder) chickens.
 ...
PMID:Involvement of lipopolysaccharide related receptors and nuclear factor kappa B in differential expression of inducible nitric oxide synthase in chicken macrophages from different genetic backgrounds. 1212 13