title: Inhibition of LPS-induced NFkappaB activation by a glucan ligand involves down-regulation of IKKbeta kinase activity and altered phosphorylation and degradation of IkappaBalpha.
abstract: Growing evidence supports the role of transcription factor activation in the pathophysiology of inflammatory disorders, sepsis, ARDS, SIRS, and shock. Kinase mediated phosphorylation of IkappaBalpha is a crucial step in the NFkappaB activation pathway. We investigated IKBalpha phosphorylation in murine liver and lung extracts after cecal ligation and puncture (CLP) in the presence and absence of a glucan ligand. ICR mice were subjected to CLP. Unoperated and sham-operated mice served as the controls. Glucan phosphate (50 mg/kg) was administered 1 h before or 15 min after CLP. CLP increased hepatic and pulmonary levels of phospho-IkappaBalpha by 48-192%. Pre- or post-treatment with glucan phosphate decreased (P < 0.05) tissue phospho-IkappaBalpha levels in CLP mice. Phospho-IkappaBalpha in the glucan-CLP group were not significantly different from the unoperated controls. To investigate mechanisms we examined IKKbeta kinase activity, IkappaBalpha phosphorylation and degradation, and NFkappaB activity in a murine macrophage cell line, J774a.1, treated with LPS (1 microg/mL) and/or glucan phosphate (1 microg/mL) for up to 120 min. The glucan ligand blunted LPS-induced IKKbeta kinase activity, phosphorylation and degradation of IkappaBalpha, and NFkappaB nuclear binding activity. The data indicate that one mechanism by which (1-->3)-beta-D-glucan may alter the response to endotoxin or polymicrobial sepsis involves modulation of IKK3 kinase activity with subsequent decreases in IkappaBalpha phosphorylation and NFkappaB activation.
authors.affiliation: Department of Surgery, James H. Quillen College of Medicine, East Tennessee State University, Johnson City 37604-0575, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Williams
authors.forename: T
authors.initials: T
authors.lastname: Ha
authors.forename: C
authors.initials: C
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Laffan
authors.forename: J
authors.initials: J
authors.lastname: Kalbfleisch
authors.forename: W
authors.initials: W
authors.lastname: Browder
mesh_terms: D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D005936:Glucans / Q000494:pharmacology* / Q000627:therapeutic use; D051550:I-kappa B Kinase; D020672:I-kappa B Proteins; D007416:Intestinal Perforation / Q000150:complications; D008024:Ligands; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors*; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008264:Macrophages; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D018805:Sepsis / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism*; D012772:Shock, Septic / Q000378:metabolism; D047071:beta-Glucans
chemical_list: D004268:DNA-Binding Proteins; D005936:Glucans; D020672:I-kappa B Proteins; D008024:Ligands; D008070:Lipopolysaccharides; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D047071:beta-Glucans; D000072000:NF-KappaB Inhibitor alpha; C033363:beta-1,3-glucan; D017346:Protein Serine-Threonine Kinases; C496564:Chuk protein, mouse; D051550:I-kappa B Kinase; C496562:Ikbkb protein, mouse; C496566:Ikbke protein, mouse