title: Induction of in vitro reprogramming by Toll-like receptor (TLR)2 and TLR4 agonists in murine macrophages: effects of TLR "homotolerance" versus "heterotolerance" on NF-kappa B signaling pathway components.
abstract: In this study, tolerance induction by preexposure of murine macrophages to Toll-like receptor (TLR)2 and TLR4 agonists was revisited, focusing on the major signaling components associated with NF-kappaB activation. Pretreatment of macrophages with a pure TLR4 agonist (protein-free Escherichia coli (Ec) LPS) or with TLR2 agonists (Porphyromonas gingivalis LPS or synthetic lipoprotein Pam3Cys) led to suppression of TNF-alpha secretion, IL-1R-associated kinase-1, and IkappaB kinase (IKK) kinase activities, c-jun N-terminal kinase, and extracellular signal-regulated kinase phosphorylation, and to suppression of NF-kappaB DNA binding and transactivation upon challenge with the same agonist (TLR4 or TLR2 "homotolerance," respectively). Despite inhibited NF-kappaB DNA binding, increased levels of nuclear NF-kappaB were detected in agonist-pretreated macrophages. For all the intermediate signaling elements, heterotolerance was weaker than TLR4 or TLR2 homotolerance with the exception of IKK kinase activity. IKK kinase activity was unperturbed in heterotolerance. TNF-alpha secretion was also suppressed in P. gingivalis LPS-pretreated, Ec LPS-challenged cells, but not vice versa, while Pam3Cys and Ec LPS did not induce a state of cross-tolerance at the level of TNF-alpha. Experiments designed to elucidate novel mechanisms of NF-kappaB inhibition in tolerized cells revealed the potential contribution of IkappaBepsilon and IkappaBxi inhibitory proteins and the necessity of TLR4 engagement for induction of tolerance to Toll receptor-IL-1R domain-containing adapter protein/MyD88-adapter-like-dependent gene expression. Collectively, these data demonstrate that induction of homotolerance affects a broader spectrum of signaling components than in heterotolerance, with selective modulation of specific elements within the NF-kappaB signaling pathway.
authors.affiliation: Department of Microbiology and Immunology, University of Maryland, Baltimore, MD 21201, USA.
authors.forename: Marina A
authors.initials: MA
authors.lastname: Dobrovolskaia
authors.forename: Andrei E
authors.initials: AE
authors.lastname: Medvedev
authors.forename: Karen E
authors.initials: KE
authors.lastname: Thomas
authors.forename: Natalia
authors.initials: N
authors.lastname: Cuesta
authors.forename: Vladimir
authors.initials: V
authors.lastname: Toshchakov
authors.forename: Tianbo
authors.initials: T
authors.lastname: Ren
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Cody
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Michalek
authors.forename: Nancy R
authors.initials: NR
authors.lastname: Rice
authors.forename: Stefanie N
authors.initials: SN
authors.lastname: Vogel
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D029721:Drosophila Proteins; D004789:Enzyme Activation / Q000276:immunology; D005260:Female; D051863:Host Cell Factor C1; D006801:Humans; D051550:I-kappa B Kinase; D007108:Immune Tolerance / Q000235:genetics; D016899:Interferon-beta / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D053592:Interleukin-1 Receptor-Associated Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000819:agonists* / Q000502:physiology*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D052002:NF-kappa B p50 Subunit; D050811:Octamer Transcription Factor-1; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D011956:Receptors, Cell Surface / Q000819:agonists* / Q000502:physiology*; D017384:Sequence Deletion; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D015534:Trans-Activators / Q000037:antagonists & inhibitors / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism; D051996:Transcription Factor RelA; D014157:Transcription Factors / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C497692:HCFC1 protein, human; C497693:Hcfc1 protein, mouse; D051863:Host Cell Factor C1; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D050811:Octamer Transcription Factor-1; C494165:POU2F1 protein, human; C494166:Pou2f1 protein, mouse; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D015534:Trans-Activators; D018808:Transcription Factor AP-1; D051996:Transcription Factor RelA; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D016899:Interferon-beta; D011494:Protein Kinases; D053592:Interleukin-1 Receptor-Associated Kinases; D017346:Protein Serine-Threonine Kinases; C496559:CHUK protein, human; C496564:Chuk protein, mouse; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human; C496562:Ikbkb protein, mouse; C496566:Ikbke protein, mouse; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases