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Mary Jackson - One of the best experts on this subject based on the ideXlab platform.

  • Secondary extended mannan side chains and attachment of the arabinan in mycobacterial Lipoarabinomannan
    Communications Chemistry, 2020
    Co-Authors: Shiva K Angala, Mary Jackson, Claudia M. Boot, Michael R Mcneil
    Abstract:

    Mycobacterial Lipoarabinomannan (LAM) is in an essential cell envelope lipopolysaccharide anchored both to the plasma and outer membranes. To understand critical biological questions such as the biosynthesis, spatial organization of LAM within the cell envelope, structural remodeling during growth, and display or lack of display of LAM-based antigenicity requires a basic understanding of the primary structure of the mannan, arabinan and how they are attached to each other. Herein, using enzymatic digestions and high-resolution mass spectrometry, we show that the arabinan component of LAM is attached at the non-reducing end of the mannan rather than to internal regions. Further, we show the presence of secondary extended mannan side chains attached to the internal mannan region. Such findings lead to a significant revision of the structure of LAM and lead to guidance of biosynthetic studies and to hypotheses of the role of LAM both in the periplasm and outside the cell as a fundamental part of the dynamic mycobacterial cell envelope. Lipoarabinomannan is a carbohydrate expressed on mycobacterial cell surfaces and implicated in host-pathogen interactions, but its structure is not well-characterised. Here mass spectrometry studies of enzymatic digests reveal the presence of secondary extended mannan pendants and indicate a revised structure for the connectivity of the core domains.

  • polysaccharide succinylation enhances the intracellular survival of mycobacterium abscessus
    ACS Infectious Diseases, 2020
    Co-Authors: Zuzana Palcekova, Michael R Mcneil, Martine Gilleron, Shiva K Angala, Juan Manuel Belardinelli, Luiz E Bermudez, Mary Jackson
    Abstract:

    Lipoarabinomannan (LAM) and its biosynthetic precursors, phosphatidylinositol mannosides (PIMs) and lipomannan (LM) play important roles in the interactions of Mycobacterium tuberculosis with phago...

  • NOTES Identification of a Polyprenylphosphomannosyl Synthase Involved in the Synthesis of Mycobacterial Mannosides†
    2009
    Co-Authors: Hataichanok Scherman, Devinder Kaur, Ha Pham, Mary Jackson
    Abstract:

    Rv3779, of the membranous GT-C superfamily responsible for the direct synthesis of polyprenyl-phospho-mannopyranose and thus indirectly for Lipoarabinomannan, lipomannan, and the higher-order phosphatidyl-myo-inositol mannosides. The mycobacterial cell envelope consists of a multilayered structure of covalently linked peptidoglycan, arabinogalactan, and mycolic acids (the mAGP complex) and, among other important constituents, various noncovalently bound glycosyl-ated lipids, notably the phosphatidyl-myo-inositol mannosides (PIMs) and their more glycosylated end products lipomannan (LM) and Lipoarabinomannan (LAM) (6, 8). These glycolipids and lipoglycans exhibit a broad range of immunomodulatory activities implicated in the pathogenesis of tuberculosis and leprosy (for recent reviews, see references 5, 8, and 10). Many steps in the biosynthesis of these phosphoinositides have been defined (for recent reviews, see references 3 an

  • Lipoarabinomannan of mycobacterium mannose capping by a multifunctional terminal mannosyltransferase
    Proceedings of the National Academy of Sciences of the United States of America, 2008
    Co-Authors: Devinder Kaur, Delphi Chatterjee, Patrick J. Brennan, Ha Pham, Andres Obregonhenao, Mary Jackson
    Abstract:

    Biosynthesis of phosphatidylinositol (PI)-containing Lipoarabinomannan (LAM) and lipomannan (LM) of Mycobacterium spp. follows a conserved pathway involving multiple membrane-associated, substrate-specific mannosyltransferases (ManTs) responsible for the sequential addition of α-mannopyranosyl (Manp) units donated by decaprenyl-P-Manp on the periplasmic side of the plasma membrane. Because of their receptor-binding and immunomodulatory properties, the α(1→2)-linked di- and tri-Manp motifs that functionalize the nonreducing arabinan termini of LAM (ManLAM) in Mycobacterium tuberculosis are of crucial importance. We now show that the M. tuberculosis ManT, Rv2181, is required for the addition of these α(1→2)-linked Manp residues but also at other locations of the LAM molecule. Structural analyses of the LM and LAM variants produced by a M. tuberculosis Rv2181 knockout mutant revealed the presence of but a single Manp residue on the nonreducing arabinan termini of LAM and also a complete absence of α(1→2)-linked Man branching on the mannan backbones of LM and LAM. A recombinant strain was constructed in ManLAM-deficient Mycobacterium smegmatis that coexpressed Rv2181 and Rv1635c—the ManT responsible for the addition of the first Manp capping residue of ManLAM. Analysis revealed LAM termini fully capped with di- and tri-Manp motifs in addition to α(1→2)Man branching on the mannan backbones of LM and LAM, confirming the involvement of the α(1→2)ManT Rv2181 in the dual role of Man capping and mannan-core branching, and in the process generated a rapidly growing, ManLAM-containing strain, a tool for the study of the role of ManLAM in the pathogenesis of tuberculosis.

  • new insights into the biosynthesis of mycobacterial lipomannan arising from deletion of a conserved gene
    Journal of Biological Chemistry, 2007
    Co-Authors: Devinder Kaur, Kayhooi Khoo, Delphi Chatterjee, Dean C. Crick, Michael R Mcneil, Mary Jackson
    Abstract:

    Genetic construction of a mutant strain (designated MSMEG4245) of Mycobacterium smegmatis, defective in a broadly conserved gene for a putative glycosyltransferase of the glycosyltransferase-C superfamily, results in a phenotype marked by the virtual absence of the phosphatidylinositol-containing lipomannan and Lipoarabinomannan, replaced instead by a novel truncated form of lipomannan. The normal spectrum of phosphatidylinositol mannosides, long presumed precursors of these lipoglycans, was retained. Matrix-assisted laser desorption/ionization-time of flight/mass spectrometry of the mutated form of lipomannan shows a family of phosphatidylinositol-anchored lipomannans with from only 5 to 20 Manp residues as compared with lipomannan from the wild type strain consisting of 21–34 Manp residues but with few changes in the branching pattern. Thus, MSMEG4245 is apparently a key mannosyltransferase, required for the proper elongation of lipomannan to its normal state and subsequent synthesis of Lipoarabinomannan. The corresponding ortholog in Mycobacterium tuberculosis H37Rv has been identified as Rv2174. This previously unrecognized feature of the biosynthesis of lipomannan/Lipoarabinomannan allows a significant revision of structural and biosynthetic schemata and provides a molecular basis of selectivity in biosynthesis, as conferred by the MSMEG4245 gene.

Olivier Neyrolles - One of the best experts on this subject based on the ideXlab platform.

  • the cell surface receptor dc sign discriminates between mycobacterium species through selective recognition of the mannose caps on Lipoarabinomannan
    Journal of Biological Chemistry, 2003
    Co-Authors: Norihiro Maeda, Brigitte Gicquel, Ali Amara, Jerome Nigou, Jeanlouis Herrmann, Mary Jackson, P H Lagrange, Germain Puzo, Olivier Neyrolles
    Abstract:

    Abstract Interactions between dendritic cells (DCs) and Mycobacterium tuberculosis, the etiological agent of tuberculosis, most likely play a key role in anti-mycobacterial immunity. We have recently shown that M. tuberculosis binds to and infects DCs through ligation of the DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) and that M. tuberculosis mannose-capped Lipoarabinomannan (ManLAM) inhibits binding of the bacilli to the lectin, suggesting that ManLAM might be a key DC-SIGN ligand. In the present study, we investigated the molecular basis of DC-SIGN ligation by LAM. Contrary to what was found for slow growing mycobacteria, such as M. tuberculosis and the vaccine strainMycobacterium bovis bacillus Calmette-Guerin, our data demonstrate that the fast growing saprophytic speciesMycobacterium smegmatis hardly binds to DC-SIGN. Consistent with the former finding, we show that M. smegmatis-derived Lipoarabinomannan, which is capped by phosphoinositide residues (PILAM), exhibits a limited ability to inhibit M. tuberculosis binding to DC-SIGN. Moreover, using enzymatically demannosylated and chemically deacylated ManLAM molecules, we demonstrate that both the acyl chains on the ManLAM mannosylphosphatidylinositol anchor and the mannooligosaccharide caps play a critical role in DC-SIGN-ManLAM interaction. Finally, we report that DC-SIGN binds poorly to the PILAM and uncapped AraLAM-containing species Mycobacterium fortuitum and Mycobacterium chelonae, respectively. Interestingly, smooth colony-formingMycobacterium avium, in which ManLAM is capped with single mannose residues, was also poorly recognized by the lectin. Altogether, our results provide molecular insight into the mechanisms of mycobacteria-DC-SIGN interaction, and suggest that DC-SIGN may act as a pattern recognition receptor and discriminate between Mycobacterium species through selective recognition of the mannose caps on LAM molecules.

  • the cell surface receptor dc sign discriminates betweenmycobacterium species through selective recognition of the mannose caps on Lipoarabinomannan
    Journal of Biological Chemistry, 2003
    Co-Authors: Norihiro Maeda, Brigitte Gicquel, Ali Amara, Jerome Nigou, Jeanlouis Herrmann, Mary Jackson, P H Lagrange, Germain Puzo, Olivier Neyrolles
    Abstract:

    Interactions between dendritic cells (DCs) and Mycobacterium tuberculosis, the etiological agent of tuberculosis, most likely play a key role in anti-mycobacterial immunity. We have recently shown that M. tuberculosis binds to and infects DCs through ligation of the DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) and that M. tuberculosis mannose-capped Lipoarabinomannan (ManLAM) inhibits binding of the bacilli to the lectin, suggesting that ManLAM might be a key DC-SIGN ligand. In the present study, we investigated the molecular basis of DC-SIGN ligation by LAM. Contrary to what was found for slow growing mycobacteria, such as M. tuberculosis and the vaccine strainMycobacterium bovis bacillus Calmette-Guerin, our data demonstrate that the fast growing saprophytic speciesMycobacterium smegmatis hardly binds to DC-SIGN. Consistent with the former finding, we show that M. smegmatis-derived Lipoarabinomannan, which is capped by phosphoinositide residues (PILAM), exhibits a limited ability to inhibit M. tuberculosis binding to DC-SIGN. Moreover, using enzymatically demannosylated and chemically deacylated ManLAM molecules, we demonstrate that both the acyl chains on the ManLAM mannosylphosphatidylinositol anchor and the mannooligosaccharide caps play a critical role in DC-SIGN-ManLAM interaction. Finally, we report that DC-SIGN binds poorly to the PILAM and uncapped AraLAM-containing species Mycobacterium fortuitum and Mycobacterium chelonae, respectively. Interestingly, smooth colony-formingMycobacterium avium, in which ManLAM is capped with single mannose residues, was also poorly recognized by the lectin. Altogether, our results provide molecular insight into the mechanisms of mycobacteria-DC-SIGN interaction, and suggest that DC-SIGN may act as a pattern recognition receptor and discriminate between Mycobacterium species through selective recognition of the mannose caps on LAM molecules.

Germain Puzo - One of the best experts on this subject based on the ideXlab platform.

  • SDS-PAGE analysis of a macroamphiphile glycopolymer from S. hygroscopicus.
    2013
    Co-Authors: Marlène Cot, Germain Puzo, Gérald Larrouy-maumus, Aurélie Ray, Alain Vercellone, Martine Gilleron, Elise Armau, Sophie Gauthier, Gérard Tiraby, Jerome Nigou
    Abstract:

    Lane 1, Mycobactrium tuberculosis LAM and LM (top and bottom bands, respectively); lane 2, S. hygroscopicus macroamphiphile glycopolymer; lane 3, S. aureus LTA. The gel was revealed by periodic acid-silver nitrate staining. LAM, Lipoarabinomannan; LM, lipomannan; LTA, lipoteichoic acid.

  • the mycobacterium tuberculosis cell surface glycoprotein apa as a potential adhesin to colonize target cells via the innate immune system pulmonary c type lectin surfactant protein a
    Journal of Biological Chemistry, 2007
    Co-Authors: Aude Ragas, Germain Puzo, Lucie Roussel, Michel Riviere
    Abstract:

    Tuberculosis is still a major health problem, and understanding the mechanism by which Mycobacterium tuberculosis (Mtb) invades and colonizes its host target cells remains an important issue for the control of infection. The innate immune system C-type lectins (C-TLs), including the human pulmonary surfactant protein A (PSP-A), have been recently identified as determinant players in the early recognition of the invading pathogen and in mounting the host defense response. Although the antigenic lipoglycan mannosylated Lipoarabinomannan is currently considered to be the major C-TL target on the mycobacterial surface, the recognition by some C-TLs of the only mycobacterial species composing the "Mtb complex" indicates that mannosylated Lipoarabinomannan cannot account alone for this specificity. Thus, we searched for the mycobacterial molecules targeted by human PSP-A, focusing our attention on the Mtb surface glycoproteins. We developed an original functional proteomic approach based on a lectin blot assay using crude human bronchoalveolar lavage fluid as a source of physiological PSP-A. Combined with selective cell-surface protein extraction and mass spectrometry peptide mapping, this strategy allowed us to identify the Apa (alanine- and proline-rich antigenic) glycoprotein as new potential target for PSP-A. This result was supported by direct binding of PSP-A to purified Apa. Moreover, EDTA addition or deglycosylation of purified Apa samples completely abolished the interaction, demonstrating that the interaction is calcium- and mannose-dependent, as expected. Finally, we provide convincing evidence that Apa, formerly considered as mainly secreted, is associated with the cell wall for a sufficiently long time to aid in the attachment of PSP-A. Because, to date, Apa seems to be restricted to the Mtb complex strains, we propose that it may account for the selective recognition of those strains by PSP-A and other immune system C-TLs containing homologous functional domains.

  • tsukamurella paurometabola lipoglycan a new Lipoarabinomannan variant with pro inflammatory activity
    Journal of Biological Chemistry, 2004
    Co-Authors: Kevin J C Gibson, Gurdyal S Besra, Germain Puzo, Martine Gilleron, Patricia Constant, Therese Brando, Jerome Nigou
    Abstract:

    The genus Tsukamurella is a member of the phylogenetic group nocardioform actinomycetes and is closely related to the genus Mycobacterium. The mycobacterial cell envelope contains lipoglycans, and of particular interest is Lipoarabinomannan, one of the most potent mycobacterial immunomodulatory molecules. We have investigated the presence of lipoglycans in Tsukamurella paurometabola and report here the isolation and structural characterization of a new Lipoarabinomannan variant, designated TpaLAM. Matrix-assisted laser desorption ionization-mass spectrometric analysis revealed that TpaLAM had an average molecular mass of 12.5 kDa and consequently was slightly smaller than Mycobacterium tuberculosis Lipoarabinomannan. Using a range of chemical degradations, NMR experiments, capillary electrophoresis, and mass spectrometry analyses, TpaLAM revealed an original carbohydrate structure. Indeed, TpaLAM contained a mannosylphosphatidyl-myo-inositol (MPI) anchor glycosylated by a linear (alpha1-->6)-Manp mannan domain, which is further substituted by an (alpha1-->5)-Araf chain. Half of the Araf units are further substituted at the O-2 position by a Manp-(alpha1-->2)-Manp-(alpha1--> dimannoside motif. Altogether, TpaLAM appears to be the most elaborated non-mycobacterial LAM molecule identified to date. TpaLAM was found to induce the pro-inflammatory cytokine tumor necrosis factor (TNF)-alpha when tested with either human or murine monocyte/macrophage cell lines. This induction was completely abrogated in the presence of an anti-toll-like receptor-2 (TLR-2) antibody, suggesting that TLR-2 participates in the mediation of TNF-alpha production in response to TpaLAM. Moreover, we established that the lipomannan core of TpaLAM is the primary moiety responsible for the observed TNF-alpha-inducing activity. This conclusively demonstrates that a linear (alpha1-->6)-Manp chain, linked to the MPI anchor, is sufficient in providing pro-inflammatory activity.

  • identification of a novel mannose capped Lipoarabinomannan from amycolatopsis sulphurea
    Biochemical Journal, 2003
    Co-Authors: Jerome Nigou, Germain Puzo, Martine Gilleron, Kevin J C Gibson, Patricia Constant, Gurdyal S Besra
    Abstract:

    The genus Amycolatopsis is a member of the phylogenetic group nocardioform actinomycetes, which also includes the genus Mycobacterium. Members of this group have a characteristic cell envelope structure, dominated by various complex lipids and polysaccharides. Amongst these, lipoglycans are of particular interest since mycobacterial Lipoarabinomannans are important immunomodulatory molecules. In this study we report the isolation and structural characterization of Amycolatopsis sulphurea Lipoarabinomannan, designated AsuLAM. SDS/PAGE analysis revealed that AsuLAM was of an intermediate size between Mycobacterium tuberculosis Lipoarabinomannan and lipomannan, confirmed by matrix-assisted laser-desorption ionization-time-of-flight mass spectrometry that predicted an average molecular mass of 10 kDa. Using a range of chemical degradations, NMR experiments and capillary electrophoresis analysis, AsuLAM was revealed as an original structure. The mannosyl-phosphatidyl- myo -inositol anchor exhibits a single acyl-form, characterized by a diacylated glycerol moiety, and contains, as one of the main fatty acids, 14-methyl-pentadecanoate, a characteristic fatty acid of the Amycolatopsis genus. AsuLAM also contains a short mannan domain; and is dominated by a multi-branched arabinan domain, composed of an (alpha1-->5)-Ara f (arabinofuranose) chain substituted, predominately at the O -2 position, by a single beta-Ara f. The arabinan domain is further elaborated by manno-oligosaccharide caps, with around one per molecule. This is the first description of manno-oligosaccharide caps found in a non-mycobacterial LAM. AsuLAM was unable to induce the production of the pro-inflammatory cytokine tumour necrosis factor alpha when tested with human or murine macrophage cell lines, reinforcing the paradigm that mannose-capped LAM are poor inducers of pro-inflammatory cytokines.

  • the cell surface receptor dc sign discriminates between mycobacterium species through selective recognition of the mannose caps on Lipoarabinomannan
    Journal of Biological Chemistry, 2003
    Co-Authors: Norihiro Maeda, Brigitte Gicquel, Ali Amara, Jerome Nigou, Jeanlouis Herrmann, Mary Jackson, P H Lagrange, Germain Puzo, Olivier Neyrolles
    Abstract:

    Abstract Interactions between dendritic cells (DCs) and Mycobacterium tuberculosis, the etiological agent of tuberculosis, most likely play a key role in anti-mycobacterial immunity. We have recently shown that M. tuberculosis binds to and infects DCs through ligation of the DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) and that M. tuberculosis mannose-capped Lipoarabinomannan (ManLAM) inhibits binding of the bacilli to the lectin, suggesting that ManLAM might be a key DC-SIGN ligand. In the present study, we investigated the molecular basis of DC-SIGN ligation by LAM. Contrary to what was found for slow growing mycobacteria, such as M. tuberculosis and the vaccine strainMycobacterium bovis bacillus Calmette-Guerin, our data demonstrate that the fast growing saprophytic speciesMycobacterium smegmatis hardly binds to DC-SIGN. Consistent with the former finding, we show that M. smegmatis-derived Lipoarabinomannan, which is capped by phosphoinositide residues (PILAM), exhibits a limited ability to inhibit M. tuberculosis binding to DC-SIGN. Moreover, using enzymatically demannosylated and chemically deacylated ManLAM molecules, we demonstrate that both the acyl chains on the ManLAM mannosylphosphatidylinositol anchor and the mannooligosaccharide caps play a critical role in DC-SIGN-ManLAM interaction. Finally, we report that DC-SIGN binds poorly to the PILAM and uncapped AraLAM-containing species Mycobacterium fortuitum and Mycobacterium chelonae, respectively. Interestingly, smooth colony-formingMycobacterium avium, in which ManLAM is capped with single mannose residues, was also poorly recognized by the lectin. Altogether, our results provide molecular insight into the mechanisms of mycobacteria-DC-SIGN interaction, and suggest that DC-SIGN may act as a pattern recognition receptor and discriminate between Mycobacterium species through selective recognition of the mannose caps on LAM molecules.

Henry W Boom - One of the best experts on this subject based on the ideXlab platform.

  • mycobacterium tuberculosis lipoprotein lprg rv1411c binds triacylated glycolipid agonists of toll like receptor 2
    Nature Structural & Molecular Biology, 2010
    Co-Authors: Michael G. Drage, Tanyun Cheng, Branch D Moody, Han-chun Tsai, Nicole D. Pecora, Supriya Shukla, Roxana E. Rojas, Chetan Seshadri, Ahmad R Arida, Henry W Boom
    Abstract:

    Knockout of lprG results in decreased virulence of Mycobacterium tuberculosis (MTB) in mice. MTB lipoprotein LprG has TLR2 agonist activity, which is thought to be dependent on its N-terminal triacylation. Unexpectedly, here we find that nonacylated LprG retains TLR2 activity. Moreover, we show LprG association with triacylated glycolipid TLR2 agonists Lipoarabinomannan, lipomannan and phosphatidylinositol mannosides (which share core structures). Binding of triacylated species was specific to LprG (not LprA) and increased LprG TLR2 agonist activity; conversely, association of glycolipids with LprG enhanced their recognition by TLR2. The crystal structure of LprG in complex with phosphatidylinositol mannoside revealed a hydrophobic pocket that accommodates the three alkyl chains of the ligand. In conclusion, we demonstrate a glycolipid binding function of LprG that enhances recognition of triacylated MTB glycolipids by TLR2 and may affect glycolipid assembly or transport for bacterial cell wall biogenesis.

Jeanlouis Herrmann - One of the best experts on this subject based on the ideXlab platform.

  • Deciphering the molecular bases of Mycobacterium tuberculosis binding to the lectin DC-SIGN reveals an underestimated complexity.
    Biochemical Journal, 2005
    Co-Authors: Sylvain Pitarque, Jeanlouis Herrmann, Mary Jackson, Bruno Payre, Jean-luc Duteyrat, Graham R Stewart, François Lecointe, Olivier Schwartz, Douglas B Young, Gilles Marchal
    Abstract:

    Interactions between dendritic cells and Mycobacterium tuberculosis, the aetiological agent of tuberculosis in humans, are thought to be central to anti-mycobacterial immunity. We have previously shown that M. tuberculosis binds to human monocyte-derived dendritic cells mostly through the C-type lectin DC-SIGN (dendritic-cell-specific intercellular molecule-3-grabbing non-integrin)/CD209, and we have suggested that DC-SIGN may discriminate between mycobacterial species through recognition of the mannose-capping residues on the lipoglycan Lipoarabinomannan of the bacterial envelope. Here, using a variety of fast- and slow-growing Mycobacterium species, we provide further evidence that mycobacteria recognition by DC-SIGN may be restricted to species of the M. tuberculosis complex. Fine analyses of the Lipoarabinomannan molecules purified from these species show that the structure and amount of these molecules alone cannot account for such a preferential recognition. We propose that M. tuberculosis recognition by DC-SIGN relies on both a potential difference of accessibility of Lipoarabinomannan in its envelope and, more probably, on the binding of additional ligands, possibly including lipomannan, mannose-capped arabinomannan, as well as the mannosylated 19 kDa and 45 kDa [Apa (alanine/proline-rich antigen)] glycoproteins. Altogether, our results reveal that the molecular basis of M. tuberculosis binding to DC-SIGN is more complicated than previously thought and provides further insight into the mechanisms of M. tuberculosis recognition by the immune system.

  • the cell surface receptor dc sign discriminates between mycobacterium species through selective recognition of the mannose caps on Lipoarabinomannan
    Journal of Biological Chemistry, 2003
    Co-Authors: Norihiro Maeda, Brigitte Gicquel, Ali Amara, Jerome Nigou, Jeanlouis Herrmann, Mary Jackson, P H Lagrange, Germain Puzo, Olivier Neyrolles
    Abstract:

    Abstract Interactions between dendritic cells (DCs) and Mycobacterium tuberculosis, the etiological agent of tuberculosis, most likely play a key role in anti-mycobacterial immunity. We have recently shown that M. tuberculosis binds to and infects DCs through ligation of the DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) and that M. tuberculosis mannose-capped Lipoarabinomannan (ManLAM) inhibits binding of the bacilli to the lectin, suggesting that ManLAM might be a key DC-SIGN ligand. In the present study, we investigated the molecular basis of DC-SIGN ligation by LAM. Contrary to what was found for slow growing mycobacteria, such as M. tuberculosis and the vaccine strainMycobacterium bovis bacillus Calmette-Guerin, our data demonstrate that the fast growing saprophytic speciesMycobacterium smegmatis hardly binds to DC-SIGN. Consistent with the former finding, we show that M. smegmatis-derived Lipoarabinomannan, which is capped by phosphoinositide residues (PILAM), exhibits a limited ability to inhibit M. tuberculosis binding to DC-SIGN. Moreover, using enzymatically demannosylated and chemically deacylated ManLAM molecules, we demonstrate that both the acyl chains on the ManLAM mannosylphosphatidylinositol anchor and the mannooligosaccharide caps play a critical role in DC-SIGN-ManLAM interaction. Finally, we report that DC-SIGN binds poorly to the PILAM and uncapped AraLAM-containing species Mycobacterium fortuitum and Mycobacterium chelonae, respectively. Interestingly, smooth colony-formingMycobacterium avium, in which ManLAM is capped with single mannose residues, was also poorly recognized by the lectin. Altogether, our results provide molecular insight into the mechanisms of mycobacteria-DC-SIGN interaction, and suggest that DC-SIGN may act as a pattern recognition receptor and discriminate between Mycobacterium species through selective recognition of the mannose caps on LAM molecules.

  • the cell surface receptor dc sign discriminates betweenmycobacterium species through selective recognition of the mannose caps on Lipoarabinomannan
    Journal of Biological Chemistry, 2003
    Co-Authors: Norihiro Maeda, Brigitte Gicquel, Ali Amara, Jerome Nigou, Jeanlouis Herrmann, Mary Jackson, P H Lagrange, Germain Puzo, Olivier Neyrolles
    Abstract:

    Interactions between dendritic cells (DCs) and Mycobacterium tuberculosis, the etiological agent of tuberculosis, most likely play a key role in anti-mycobacterial immunity. We have recently shown that M. tuberculosis binds to and infects DCs through ligation of the DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) and that M. tuberculosis mannose-capped Lipoarabinomannan (ManLAM) inhibits binding of the bacilli to the lectin, suggesting that ManLAM might be a key DC-SIGN ligand. In the present study, we investigated the molecular basis of DC-SIGN ligation by LAM. Contrary to what was found for slow growing mycobacteria, such as M. tuberculosis and the vaccine strainMycobacterium bovis bacillus Calmette-Guerin, our data demonstrate that the fast growing saprophytic speciesMycobacterium smegmatis hardly binds to DC-SIGN. Consistent with the former finding, we show that M. smegmatis-derived Lipoarabinomannan, which is capped by phosphoinositide residues (PILAM), exhibits a limited ability to inhibit M. tuberculosis binding to DC-SIGN. Moreover, using enzymatically demannosylated and chemically deacylated ManLAM molecules, we demonstrate that both the acyl chains on the ManLAM mannosylphosphatidylinositol anchor and the mannooligosaccharide caps play a critical role in DC-SIGN-ManLAM interaction. Finally, we report that DC-SIGN binds poorly to the PILAM and uncapped AraLAM-containing species Mycobacterium fortuitum and Mycobacterium chelonae, respectively. Interestingly, smooth colony-formingMycobacterium avium, in which ManLAM is capped with single mannose residues, was also poorly recognized by the lectin. Altogether, our results provide molecular insight into the mechanisms of mycobacteria-DC-SIGN interaction, and suggest that DC-SIGN may act as a pattern recognition receptor and discriminate between Mycobacterium species through selective recognition of the mannose caps on LAM molecules.