Molecular Regulation of Inducible Nitric Oxide Synthase Gene in Chicken Macrophages

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dc.contributor.advisor J. B. Allen, Committee Member en_US
dc.contributor.advisor P. B. Carter, Committee Member en_US
dc.contributor.advisor F. W. Edens, Committee Member en_US
dc.contributor.advisor M. A. Qureshi, Committee Chair en_US Dil, Nyla en_US 2010-04-02T18:27:51Z 2010-04-02T18:27:51Z 2002-08-19 en_US
dc.identifier.other etd-05212002-100800 en_US
dc.description.abstract Inducible nitric oxide synthase serves as an important mediator of macrophage immunobiology by regulating the biosynthesis of nitric oxide that in turn mediates several immunological and physiological functions. Previous studies have demonstrated that macrophages from Cornell K-strain chickens (B15B15) were hyper-responsive to Escherichia coli LPS whereas macrophages from GB1 (B13B13) and GB2 (B6B6) chickens were hypo-responsive for inducible nitric oxide synthase (iNOS) expression and activity. Furthermore, this differential iNOS induction in response to LPS was transcriptionally regulated. The current study was conducted to explore the molecular basis of strain-based differential iNOS induction in chicken macrophages. In the first study, macrophages from K-strain, GB1, GB2 chickens and MQ-NCSU macrophage cell line were exposed to LPS from three sources other than E.coli and both iNOS activity and expression were studied. iNOS mRNA and nitrite data showed that these strain-based differences are intrinsic in nature and not limited to the bacterial source of LPS. In addition, when surface expression of LPS-related receptors was studied via flow cytometry, macrophages from the K-strain exhibited higher numbers of LPS signal transducing molecule TLR4 constitutively in comparison to GB2 macrophages. In the second study, inducible expression of LPS related receptors as well as NFkappaB activation and the involvement of these proteins in iNOS induction was studied. LPS exposure induced significantly higher numbers of inducible TLR4 and CD14 molecules on K-strain macrophages and a significantly higher corresponding increase in NFkappaB activation as compared with GB2 macrophages. Furthermore, blocking studies revealed that CD14, TLR4 and NFkappaB activation were all involved in LPS mediated iNOS induction in chicken macrophages. The objective of the third study was to examine the expression of IL-1beta and to explore if LPS-mediated induction of IL-1beta modulates iNOS induction in these genetic lines of chickens. Initially GB2 and K strain macrophages produced comparable IL-1beta mRNA soon after LPS stimulation. However, IL-1beta mRNA persisted up to 9 h only on GB2 macrophages and LPS-inducible IL-1 surface receptor expression was also found to be higher in GB2 than on K-strain macrophages. In addition, blocking of IL-1 receptor by the anti-IL-1 receptor antibody inhibited the LPS mediated iNOS induction by 50% both in K and GB2 chickens indicating that IL-1beta does not contribute to differential iNOS induction in these chicken lines. Overall these studies demonstrate that strain based differences in iNOS expression in chickens are mediated via enhanced expression of LPS related receptors. en_US
dc.rights I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. en_US
dc.subject INDUCIBLE en_US
dc.subject NITRIC OXIDE en_US
dc.subject SYNTHASE en_US
dc.subject GENE en_US
dc.subject CHICKEN en_US
dc.subject MACROPHAGES en_US
dc.title Molecular Regulation of Inducible Nitric Oxide Synthase Gene in Chicken Macrophages en_US PhD en_US dissertation en_US Immunology en_US

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