title: Inhibition of LPS-induced cytokines by Bcl-xL in a murine macrophage cell line.
abstract: The antiapoptotic molecule Bcl-xL has been implicated in the differentiation and survival of activated macrophages in inflammatory conditions. In this report, the role of Bcl-xL in LPS-induced cytokine gene expression and secretion was studied. Bcl-xL-transfected RAW 264 macrophages were protected from gliotoxin-induced apoptosis, indicating the presence of functional Bcl-xL. Overexpression of Bcl-xL in this macrophage cell line was also associated with a marked inhibition of LPS-induced TNF-alpha, JE/monocyte chemoattractant protein 1, and macrophage inflammatory protein 2 secretion. Inhibition of LPS-induced cytokine secretion was paralleled by a decrease in levels of steady-state mRNA for the above cytokines and for IL-1beta. Decreased production of TNF-alpha in Bcl-xL transfectants was not due to increased mRNA degradation, as the mRNA half-lives were the same in Bcl-xL transfectants and control macrophages. Although the composition of NF-kappaB complexes detected by EMSA and supershift analysis in nuclear lysates derived from Bcl-xL transfectants and control cells was indistinguishable, LPS-induced inhibitory kappaBalpha degradation, as well as NF-kappaB binding and AP-1 activation, were slightly decreased by ectopic expression of Bcl-xL. More strikingly, LPS-induced phosphorylation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase was strongly repressed by Bcl-xL overexpression, offering a possible mechanism for the inhibition of LPS-induced cytokine production. These data provide the first evidence for a novel role for Bcl-xL as an anti-inflammatory mediator in macrophages.
authors.affiliation: Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
authors.forename: V
authors.initials: V
authors.lastname: Lakics
authors.forename: A E
authors.initials: AE
authors.lastname: Medvedev
authors.forename: S
authors.initials: S
authors.lastname: Okada
authors.forename: S N
authors.initials: SN
authors.lastname: Vogel
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology; D001692:Biological Transport / Q000276:immunology; D002460:Cell Line; D002999:Clone Cells; D016207:Cytokines / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D005912:Gliotoxin / Q000494:pharmacology; D020672:I-kappa B Proteins; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008264:Macrophages / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational / Q000276:immunology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D015533:Transcriptional Activation / Q000276:immunology; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D051020:bcl-X Protein; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: C494812:Bcl2l1 protein, mouse; D016207:Cytokines; D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D007166:Immunosuppressive Agents; D008070:Lipopolysaccharides; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D051020:bcl-X Protein; D000072000:NF-KappaB Inhibitor alpha; D005912:Gliotoxin; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases