title: Toll-like receptor 2 (TLR2)-dependent-positive and TLR2-independent-negative regulation of proinflammatory cytokines by mycobacterial lipomannans.
abstract: Lipoarabinomannans (LAM) and lipomannans (LM) are integral parts of the mycobacterial cell wall recognized by cells involved in the innate immune response and have been found to modulate the cytokine response. Typically, mannosylated LAM from pathogenic mycobacteria have been reported to be anti-inflammatory, whereas phosphoinositol-substituted LAM from nonpathogenic species are proinflammatory molecules. In this study, we show that LM from several mycobacterial species, including Mycobacterium chelonae, Mycobacterium kansasii, and Mycobacterium bovis bacillus Calmette-Guérin, display a dual function by stimulating or inhibiting proinflammatory cytokine synthesis through different pathways in murine primary macrophages. LM, but none of the corresponding LAM, induce macrophage activation characterized by cell surface expression of CD40 and CD86 and by TNF and NO secretion. This activation is dependent on the presence of Toll-like receptor (TLR) 2 and mediated through the adaptor protein myeloid differentiation factor 88 (MyD88), but independent of either TLR4 or TLR6 recognition. Surprisingly, LM exerted also a potent inhibitory effect on TNF, IL-12p40, and NO production by LPS-activated macrophages. This TLR2-, TLR6-, and MyD88-independent inhibitory effect is also mediated by LAM from M. bovis bacillus Calmette-Guérin but not by LAM derived from M. chelonae and M. kansasii. This study provides evidence that mycobacterial LM bear structural motifs susceptible to interact with different pattern recognition receptors with pro- or anti-inflammatory effects. Thus, the ultimate response of the host may therefore depend on the prevailing LM or LAM in the mycobacterial envelope and the local host cell receptor availability.
authors.affiliation: NRS Centre National de la Recherche Scientifique, Molecular Immunology and Embryology, Orléans, France.
authors.forename: Valerie J
authors.initials: VJ
authors.lastname: Quesniaux
authors.forename: Delphine M
authors.initials: DM
authors.lastname: Nicolle
authors.forename: David
authors.initials: D
authors.lastname: Torres
authors.forename: Laurent
authors.initials: L
authors.lastname: Kremer
authors.forename: Yann
authors.initials: Y
authors.lastname: Guérardel
authors.forename: Jérôme
authors.initials: J
authors.lastname: Nigou
authors.forename: Germain
authors.initials: G
authors.lastname: Puzo
authors.forename: François
authors.initials: F
authors.lastname: Erard
authors.forename: Bernhard
authors.initials: B
authors.lastname: Ryffel
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000943:Antigens, Differentiation / Q000235:genetics / Q000502:physiology; D002478:Cells, Cultured; D016207:Cytokines / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000378:metabolism; D015536:Down-Regulation / Q000276:immunology*; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018664:Interleukin-12 / Q000037:antagonists & inhibitors / Q000378:metabolism; D053762:Interleukin-12 Subunit p40; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D009163:Mycobacterium bovis / Q000276:immunology; D016926:Mycobacterium chelonae / Q000276:immunology*; D019909:Mycobacterium kansasii / Q000276:immunology*; D053594:Myeloid Differentiation Factor 88; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000378:metabolism; D021122:Protein Subunits / Q000037:antagonists & inhibitors / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D011971:Receptors, Immunologic / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism; D015854:Up-Regulation / Q000276:immunology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000943:Antigens, Differentiation; D016207:Cytokines; D018836:Inflammation Mediators; D053762:Interleukin-12 Subunit p40; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D021122:Protein Subunits; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha; C050016:lipoarabinomannan; C064351:lipomannan; D018664:Interleukin-12; D009569:Nitric Oxide