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dc.contributor.advisorRamos, Kennethen_US
dc.creatorWilliams, Edward Spenceren_US
dc.date.accessioned2004-09-30T01:44:50Z
dc.date.available2004-09-30T01:44:50Z
dc.date.created2003-12en_US
dc.date.issued2004-09-30
dc.identifier.urihttp://hdl.handle.net/1969.1/175
dc.description.abstractNF-κB activity is critical in the regulation of atherosclerotic vascular smooth muscle cell (vSMC) phenotypes induced following oxidative injury by allylamine. The present studies were designed to detail dysregulation of NF-κB activity in these altered phenotypes, and to assess the importance of NF-κB in the regulation of osteopontin, a cytokine which modulates atherosclerosis. Increased degradation of IκBα was observed in allylamine-induced atherosclerotic vSMC phenotypes (henceforth referred to as allylamine cells). Enhanced phosphorylation of I-κ-kinases was observed by Western immunoblotting. NF-κB DNA binding activity as assessed by electrophoretic mobility shift assay demonstrated changes in the kinetics and magnitude of induction of binding. Enhancement of NF-κB binding activity was evident in allylamine cells compared to controls when seeded on plastic, fibronectin, and laminin, but not collagen I. Posttranscriptional alterations in Rel protein expression and nuclear localization partly account for changes in NF-κB DNA binding activity. Promoter-specific NF-κB binding profiles suggest altered dimer prevalence as a consequence of the changes in Rel protein expression. The expression of NF-κB regulated genes osteopontin and MMP-2 was enhanced in allylamine-treated aortas, while cyclin D1 and MMP-9 were unchanged. As the importance of osteopontin in atherosclerosis has been described in several models, subsequent studies were designed to assess osteopontin promoter activity. Activity of the osteopontin promoter was significantly reduced in allylamine cells compared to controls as assessed using a luciferase reporter. Deletion analysis suggested the presence of inhibitory cis-acting elements in the regulatory region of the gene. Mutation of these elements, including VDRE, AP-1, NF-κB, and USF1, indicated that NF-κB and USF1 mediate suppression of osteopontin promoter activity in allylamine cells. Decreased serine phosphorylation of immunoprecipitated RelA/p65 was observed in allylamine cells, indicating decreased ability of this protein to transactive gene promoters. NF-κB was found to play a role in suppression of osteopontin promoter activity by collagen I-mediated integrin signaling. These findings suggest that enhancements in NF-κB activity suppress osteopontin promoter activity in oxidant-activated vSMC cultures. Dysregulation of NF-κB activity occurs as a result of altered matrix and intracellular signaling upstream of the nucleus and possibly differential dimer assembly leading to cell-specific profiles of NF-κB-dependent gene regulation.en_US
dc.format.extent4044507 bytes
dc.format.extent134690 bytes
dc.format.mediumelectronicen_US
dc.format.mimetypeapplication/pdf
dc.format.mimetypetext/plain
dc.language.isoen_USen_US
dc.publisherTexas A&M Universityen_US
dc.subjectatherosclerosisen_US
dc.subjectoxidative stressen_US
dc.subjectallylamineen_US
dc.subjectvascular smooth muscle cellsen_US
dc.titleDysregulation of nuclear factor kappa B activity and osteopontin expression in oxidant-induced atherogenesisen_US
dc.typeBooken
dc.typeThesisen
thesis.degree.departmentVeterinary Physiology and Pharmacologyen_US
thesis.degree.disciplineToxicologyen_US
thesis.degree.grantorTexas A&M Universityen_US
thesis.degree.nameDoctor of Philosophyen_US
thesis.degree.levelDoctoralen_US
dc.contributor.committeeMemberSafe, Stephenen_US
dc.contributor.committeeMemberBurghardt, Roberten_US
dc.contributor.committeeMemberWilson, Emilyen_US
dc.type.genreElectronic Dissertationen_US
dc.type.materialtexten_US
dc.format.digitalOriginborn digitalen_US


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