The Experts below are selected from a list of 408 Experts worldwide ranked by ideXlab platform
Gurdyal S Besra - One of the best experts on this subject based on the ideXlab platform.
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Disruption of Mycobacterial AftB Results in Complete Loss of Terminal β(1 → 2) Arabinofuranose Residues of Lipoarabinomannan
2016Co-Authors: Monika Jankute, Natacha Veerapen, Jérôme Nigou, Luke J Alderwick, Stephan Noack, Gurdyal S BesraAbstract:Lipoarabinomannan (LAM) and arabinogalactan (AG) are the two major mycobacterial cell wall (lipo)polysaccharides, which contain a structurally similar arabinan domain that is highly branched and assembled in a stepwise fashion by variety of arabinofuranosyltransferases (ArafT). In addition to playing an essential role in mycobacterial physiology, LAM and its biochemical precursor Lipomannan possess potent immunomodulatory activities that affect the host immune response. In the search of additional mycobacterial ArafTs that participate in the synthesis of the arabinan segment of LAM, we disrupted aftB (MSMEG_6400) in Mycobacterium smegmatis. The deletion of chromosomal aftB locus could only be achieved in the presence of a rescue plasmid carrying a functional copy of aftB, strongly suggesting that it is essential for the viability of M. smegmatis. Isolation and detailed structural characterization of a LAM molecule derived from the conditional mutant deficient in AftB revealed the absence of terminal β(1 → 2)-linked arabinofuranosyl residues. Furthermore, we demonstrated that truncated LAM displays proinflammatory activity, which is due to its ability to activate Toll-like receptor 2. All together, our results indicate that AftB is an essential mycobacterial ArafT that plays a role in the synthesis of the arabinan domain of LAM
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Structure of the lipid anchor of bacterial macroamphiphiles.
2013Co-Authors: Landry Blanc, Arun K. Mishra, Gurdyal S Besra, Romain Castanier, Aurélie Ray, Iain Sutcliffe, Alain Vercellone, Jérôme NigouAbstract:CgLM, Corynebacterium glutamicum Lipomannan; DAG, diacylglycerol; FSL-1, synthetic N-terminal part of lipopoprotein LP44 of Mycoplasma salivarum; MlLM, Micrococcus luteus Lipomannan; MPI, mannosyl-phosphatidyl-myo-inositol; MsLM, Mycobacterium smegmatis Lipomannan; PGP, polyglycerolphosphate; SaLTA, Staphylococcus aureus lipoteichoic acid; The available evidence [29] suggests the structure of Stomatococcus mucilaginosus Lipomannan (SmLM) is very similar to that of MlLM.
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differential arabinan capping of lipoarabinomannan modulates innate immune responses and impacts t helper cell differentiation
Journal of Biological Chemistry, 2012Co-Authors: Arun K. Mishra, Karin Krumbach, Lothar Eggeling, Jérôme Nigou, Joana Alves, Antonio G Castro, Jeroen Geurtsen, Margarida Saraiva, Gurdyal S BesraAbstract:Toll-like receptors (TLRs) recognize pathogens by interacting with pathogen-associated molecular patterns, such as the phosphatidylinositol-based lipoglycans, Lipomannan (LM) and lipoarabinomannan (LAM). Such structures are present in several pathogens, including Mycobacterium tuberculosis, being important for the initiation of immune responses. It is well established that the interaction of LM and LAM with TLR2 is a process dependent on the structure of the ligands. However, the implications of structural variations on TLR2 ligands for the development of T helper (Th) cell responses or in the context of in vivo responses are less studied. Herein, we used Corynebacterium glutamicum as a source of lipoglycan intermediates for host interaction studies. In this study, we have deleted a putative glycosyltransferase, NCgl2096, from C. glutamicum and found that it encodes for a novel α(1→2)arabinofuranosyltransferase, AftE. Biochemical analysis of the lipoglycans obtained in the presence (wild type) or absence of NCgl2096 showed that AftE is involved in the biosynthesis of singular arabinans of LAM. In its absence, the resulting molecule is a hypermannosylated (hLM) form of LAM. Both LAM and hLM were recognized by dendritic cells, mainly via TLR2, and triggered the production of several cytokines. hLM was a stronger stimulus for in vitro cytokine production and, as a result, a more potent inducer of Th17 responses. In vivo data confirmed hLM as a stronger inducer of cytokine responses and suggested the involvement of pattern recognition receptors other than TLR2 as sensors for lipoglycans.
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deletion of manc in corynebacterium glutamicum results in a phospho myo inositol mannoside and lipoglycan deficient mutant
Microbiology, 2012Co-Authors: Arun K. Mishra, Sarah M Batt, Karin Krumbach, Gurdyal S Besra, Doris Rittmann, Oona Y C Lee, Julia Frunzke, Lothar EggelingAbstract:Mannose is an important constituent of the immunomodulatory glycoconjugates of the mycobacterial cell wall: lipoarabinomannan (LAM), Lipomannan (LM) and the related phospho-myo-inositol mannosides (PIMs). In Mycobacterium tuberculosis and the related bacillus Corynebacterium glutamicum, mannose is either imported from the medium or derived from glycolysis, and is subsequently converted into the nucleotide-based sugar donor guanosine diphosphomannose (GDP-mannose). This can be utilized by the glycosyltranferases of the GT-A/B superfamily or converted to the lipid-based donor polyprenyl monophosphomannose, and used as a substrate by the transmembrane glycosyltransferases of the GT-C superfamily. To investigate GDP-mannose biosynthesis in detail, the gene encoding a putative ManC in C. glutamicum was deleted. Deletion of manC resulted in a slow-growing mutant, with reduced but not totally abrogated guanosine diphosphomannose pyrophosphorylase activity. However, a comprehensive cell wall analysis revealed that C. glutamicumΔmanC is deficient in PIMs and LM/LAM. Closer inspection suggests that promiscuous ManC activity is contributed by additional putative nucleotidyltransferases, PmmB, WbbL1, GalU and GlmU, and a hypothetical protein, NCgl0715. Furthermore, complementation analyses of C. glutamicumΔmanC with Rv3264c suggested that it is a true homologue of ManC in M. tuberculosis, and the essentiality of PIMs in M. tuberculosis makes it an attractive drug target.
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Ppm1-Encoded Polyprenyl Monophosphomannose Synthase Activity Is Essential for Lipoglycan Synthesis and Survival in Mycobacteria
2012Co-Authors: Amrita K. Rana, Albel Singh, Sudagar S. Gurcha, Liam R. Cox, Apoorva Bhatt, Gurdyal S BesraAbstract:The biosynthesis of mycobacterial mannose-containing lipoglycans, such as Lipomannan (LM) and the immunomodulator lipoarabinomanan (LAM), is carried out by the GT-C superfamily of glycosyltransferases that require polyprenylphosphate-based mannose (PPM) as a sugar donor. The essentiality of lipoglycan synthesis for growth makes the glycosyltransferase that synthesizes PPM, a potential drug target in Mycobacterium tuberculosis, the causative agent of tuberculosis. In M. tuberculosis, PPM has been shown to be synthesized by Ppm1 in enzymatic assays. However, genetic evidence for its essentiality and in vivo role in LM/LAM and PPM biosynthesis is lacking. In this study, we demonstrate that MSMEG3859, a Mycobacterium smegmatis gene encoding the homologue of the catalytic domain of M. tuberculosis Ppm1, is essential for survival. Depletion of MSMEG3859 in a conditional mutant of M. smegmatis resulted in the loss of higher order phosphatidyl-myo-inositol mannosides (PIMs) and Lipomannan. We were also able to demonstrate that two other M. tuberculosis genes encoding glycosyltransferases that either had been shown to possess PPM synthase activity (Rv3779), or were involved in synthesizing similar polyprenol-linked donors (ppgS), were unable to compensate for the loss of MSMEG3859 in the conditional mutant
Laurent Kremer - One of the best experts on this subject based on the ideXlab platform.
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Mycobacterial Lipomannan induces MAP kinase phosphatase-1 expression in macrophages.
FEBS Letters, 2008Co-Authors: Elisabeth Elass, Bernadette Coddeville, Laurent Kremer, Marlène Mortuaire, Joël Mazurier, Yann GuérardelAbstract:Mycobacterial Lipomannan (LM) and lipoarabinomannan (LAM) regulate macrophage activation by interacting with Toll-like receptors (TLRs). The intracellular signalling pathways elicited by these complex molecules are poorly defined. We have demonstrated that LM purified from various mycobacterial species, but not LAM from Mycobacterium kansasii or Mycobacterium bovis BCG, induced expression of the MAP kinase phosphatase 1 (MKP-1) in macrophages. Anti-TLR2 antibodies, as well as specific ERK and p38 MAPK inhibitors, decreased MKP-1 transcription in LM-stimulated cells. These findings suggest that the binding of LM to TLR2 triggers MAPK activation, followed by an up-regulation of MKP-1 expression, which in turn may act as a negative regulator of MAPK activation.
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Polysaccharide structural variability in mycobacteria: identification and characterization of phosphorylated mannan and arabinomannan.
Glycoconjugate Journal, 2007Co-Authors: Emmanuel Maes, Bernadette Coddeville, Laurent Kremer, Yann GuérardelAbstract:Arabinomannan (AMannan) and mannan (Mannan) are major polysaccharides antigens of the mycobacterial capsule. They are highly related to the lipoarabinomannan (LAM) and Lipomannan (LM) lipoglycans of the cell wall, known to participate to the immunopathogenesis of mycobacterial infections. Here we present the identification of two related polysaccharides from Mycobacterium kansasii that co-purified with AMannan and Mannan. Structural analysis using GC, MALDI-MS and NMR clearly established these molecules as non-acylated phosphorylated AMannan and Mannan designated P-AMannan and P-Mannan, respectively. These glycoconjugates represent a new source of polysaccharide structural variability in mycobacteria and constitute unique tools for structure-activity relationship studies in order to investigate the role of fatty acids in the biological functions of LAM and LM. The potential participation of these polysaccharides in influencing the outcome of the infection is also discussed.
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Identification by surface plasmon resonance of the mycobacterial Lipomannan and lipoarabinomannan domains involved in binding to CD14 and LPS-binding protein.
FEBS Letters, 2007Co-Authors: Elisabeth Elass, Emmanuel Maes, Bernadette Coddeville, Laurent Kremer, Yann Guérardel, Joël Mazurier, Dominique LegrandAbstract:The mycobacterial lipoglycans, Lipomannan (LM) and lipoarabinomannan (LAM), regulate host defence mechanisms through their interaction with pattern recognition receptors such as Toll-like receptors (TLRs). We have developed a surface plasmon resonance assay to analyse the molecular basis for the recognition of Mycobacterium kansasii LM or LAM, by immobilized CD14 and LPS-binding protein (LBP) both being capable to promote presentation of bacterial glycolipids to TLRs. The affinity of either LM/LAM was higher to CD14 than to LBP. Kinetic and Scatchard analyses were consistent with a model involving a single class of binding sites. These interactions required the lipidic anchor, but not the carbohydrate domains, of LM or LAM. We also provide evidence that addition of recombinant LBP enhanced the stimulatory effect of LM or LAM on matrix metalloproteinase-9 expression and secretion in macrophages, through a TLR1/TLR2-dependent mechanism.
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Mycobacterial Lipomannan induces granuloma macrophage fusion via a TLR2-dependent, ADAM9- and beta1 integrin-mediated pathway.
Journal of Immunology, 2007Co-Authors: Marie-pierre Puissegur, Yann Guérardel, Martine Gilleron, Guillaume Lay, Laure Botella, Jérôme Nigou, Hedia Marrakchi, Bernard Mari, Jean-luc Duteyrat, Laurent KremerAbstract:Tuberculous granulomas are the sites of interaction between the host response and the tubercle bacilli within infected individuals. They mainly consist of organized aggregations of lymphocytes and macrophages (Mf). A predominant role of mycobacterial envelope glycolipids in granulomas formation has been recently emphasized, yet the signaling events interfering with granuloma cell differentiation remain elusive. To decipher this molecular machinery, we have recently developed an in vitro human model of mycobacterial granulomas. In this study, we provide evidence that the mycobacterial proinflammatory phosphatidyl-myo-inositol mannosides and Lipomannans (LM), as well as the anti-inflammatory lipoarabinomannan induce granuloma formation, yet only the proinflammatory glycolipids induce the fusion of granuloma Mf into multinucleated giant cells (MGC). We also demonstrate that LM induces large MGC resembling those found in vivo within the granulomas of tuberculosis patients, and that this process is mediated by TLR2 and is dependent on the beta(1) integrin/ADAM9 cell fusion machinery. Our results demonstrate for the first time that the Mf differentiation stage specifically occurring within granulomatous structures (i.e., MGC formation) is triggered by mycobacterial envelope glycolipids, which are capable of inducing the cell fusion machinery. This provides the first characterization of the ontogeny of human granuloma MGC, thus resulting in a direct modulation by a particular mycobacterial envelope glycolipid of the differentiation process of granuloma Mf.
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Mycobacterial Lipomannan induces matrix metalloproteinase-9 expression in human macrophagic cells through a Toll-like receptor 1 (TLR1)/TLR2- and CD14-dependent mechanism.
Infection and Immunity, 2005Co-Authors: Elisabeth Elass, Emmanuel Maes, Yann Guérardel, Joël Mazurier, Laetitia Aubry, Maryse Masson, Denys Agnès, Dominique Legrand, Laurent KremerAbstract:Lipomannans (LM) from various mycobacterial species were found to induce expression and secretion of the matrix metalloproteinase 9 (MMP-9) both in human macrophage-like differentiated THP-1 cells and in primary human macrophages. Inhibition studies using antireceptor-neutralizing antibodies are indicative of a Toll-like receptor 1 (TLR1)/TLR2- and CD14-dependent signaling mechanism. Moreover, LM was shown to down-regulate transcription of the metalloproteinase inhibitor TIMP-1, a major endogenous MMP-9 regulator.
Siwarutt Boonyarattanakalin - One of the best experts on this subject based on the ideXlab platform.
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synthetic Lipomannan glycan microarray reveals the importance of α 1 2 mannose branching in dc sign binding
Journal of Organic Chemistry, 2019Co-Authors: Nithinan Sawettanai, Somsak Ruchirawat, Harin Leelayuwapan, Nitsara Karoonuthaisiri, Siwarutt BoonyarattanakalinAbstract:Lipomannan (LM), a glycophospholipid found on the cell surface of mycobacteria, involves the virulence and survival in host cells. However, there is little to no information on how exactly mannan alignment, including the number of mannose units and the branched motif of LM, affects protein engagement during host-pathogen interactions. In this study, we synthesized the exact substructures of the LM glycans that consist of an α(1,6) mannan core, with and without the complete α(1,2) mannose branching, and comparatively studied their protein-carbohydrate interactions. The synthetic LM glycans were equipped with a thiol linker for immobilizations on the surfaces of microarrays. As per our findings, the presence of the branching α(1,2) mannose on the LM glycans increases their binding toward the dendritic cell-specific intercellular adhesion molecule-3 grabbing non-integrin receptor. An increase in the number of mannose units on the glycans also increases the binding with the mannose receptor. Thus, the set of synthetic glycans can serve as a useful tool to study the biological activities of LM and can provide a better understanding of host-pathogen interactions.
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synthesis and immunological studies of the Lipomannan backbone glycans found on the surface of mycobacterium tuberculosis
Journal of Organic Chemistry, 2017Co-Authors: Harin Leelayuwapan, Niwat Kangwanrangsan, Runglawan Chawengkirttikul, Marisa Ponpuak, Ratthaphol Charlermroj, Kanokthip Boonyarattanakalin, Somsak Ruchirawat, Siwarutt BoonyarattanakalinAbstract:Investigations into novel bacterial drug targets and vaccines are necessary to overcome tuberculosis. Lipomannan (LM), found on the surface of Mycobacterium tuberculosis (Mtb), is actively involved in the pathogenesis and survival of Mtb. Here, we report for the first time a rapid synthesis and biological activities of an LM glycan backbone, α(1–6)mannans. The rapid synthesis is achieved via a regio- and stereoselective ring opening polymerization to generate multiple glycosidic bonds in one simple chemical step, allowing us to finish assembling the defined polysaccharides of 5–20 units within days rather than years. Within the same pot, the polymerization is terminated by a thiol-linker to serve as a conjugation point to carrier proteins and surfaces for immunological experiments. The synthetic glycans are found to have adjuvant activities in vivo. The interactions with DC-SIGN demonstrated the significance of α(1–6)mannan motif present in LM structure. Moreover, surface plasmon resonance (SPR) showed th...
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Synthesis and Immunological Studies of the Lipomannan Backbone Glycans Found on the Surface of Mycobacterium tuberculosis
2017Co-Authors: Harin Leelayuwapan, Niwat Kangwanrangsan, Runglawan Chawengkirttikul, Marisa Ponpuak, Ratthaphol Charlermroj, Kanokthip Boonyarattanakalin, Somsak Ruchirawat, Siwarutt BoonyarattanakalinAbstract:Investigations into novel bacterial drug targets and vaccines are necessary to overcome tuberculosis. Lipomannan (LM), found on the surface of Mycobacterium tuberculosis (Mtb), is actively involved in the pathogenesis and survival of Mtb. Here, we report for the first time a rapid synthesis and biological activities of an LM glycan backbone, α(1–6)mannans. The rapid synthesis is achieved via a regio- and stereoselective ring opening polymerization to generate multiple glycosidic bonds in one simple chemical step, allowing us to finish assembling the defined polysaccharides of 5–20 units within days rather than years. Within the same pot, the polymerization is terminated by a thiol-linker to serve as a conjugation point to carrier proteins and surfaces for immunological experiments. The synthetic glycans are found to have adjuvant activities in vivo. The interactions with DC-SIGN demonstrated the significance of α(1–6)mannan motif present in LM structure. Moreover, surface plasmon resonance (SPR) showed that longer chain of synthetic α(1–6)mannans gain better lectin’s binding affinity. The chemically defined components of the bacterial envelope serve as important tools to reveal the interactions of Mtb with mammalian hosts and facilitate the determination of the immunologically active molecular components
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polymerization of mannosyl tricyclic orthoesters for the synthesis of α 1 6 mannopyranan the backbone of Lipomannan
Bioorganic & Medicinal Chemistry, 2010Co-Authors: Chanokpon Yongyat, Somsak Ruchirawat, Siwarutt BoonyarattanakalinAbstract:Abstract Tuberculosis (TB) remains a major health problem worldwide. Understanding the interactions between the surface components of Mycobacterium tuberculosis ( Mtb ), the main causative agent of TB, with host immune response will be critical for developments of effective treatments and prevention of TB. Chemically defined mimics of the bacterial envelope components serve as important tools for biological studies of the bacterial interactions with mammalian hosts. We report here a rapid synthetic approach utilizing mannosyl tricyclic orthoesters as monomers for regio- and stereo-controlled polymerizations to generate α(1–6) mannopyranan—the backbone of Lipomannan. The polymerizations generated multiple glycosidic bonds in a single chemical transformation in regio- and stereo-selective manners. TMSOTf is the optimum catalyst to promote the selective and high yielding polymerization when compared with other Lewis acids. In addition, the monomers 3,4- O -benzyl-β- d -mannopyranose 1,2,6-orthobenzoate ( 1 ) and 3,4- O -benzyl-β- d -mannopyranose 1,2,6-orthopivalate ( 2 ) can be synthesized in multiple-gram scale and in a rapid fashion. Characterizations by GPC and NMR indicate the identity of α(1–6) mannopyranan with DPn (degree of polymerization) = 20.
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Chemical synthesis of all phosphatidylinositol mannoside (PIM) glycans from Mycobacterium tuberculosis.
Journal of the American Chemical Society, 2008Co-Authors: Siwarutt Boonyarattanakalin, Xinyu Liu, Mario Michieletti, Bernd Lepenies, Peter H. SeebergerAbstract:The emergence of multidrug-resistant tuberculosis (TB) and problems with the BCG tuberculosis vaccine to protect humans against TB have prompted investigations into alternative approaches to combat this disease by exploring novel bacterial drug targets and vaccines. Phosphatidylinositol mannosides (PIMs) are biologically important glycoconjugates and represent common essential precursors of more complex mycobacterial cell wall glycolipids including Lipomannan (LM), lipoarabinomannan (LAM), and mannan capped lipoarabinomannan (ManLAM). Synthetic PIMs constitute important biochemical tools to elucidate the biosynthesis of this class of molecules, to reveal PIM interactions with host cells, and to investigate the function of PIMs as potential antigens and/or adjuvants for vaccine development. Here, we report the efficient synthesis of all PIMs including phosphatidylinositol (PI) and phosphatidylinositol mono- to hexa-mannoside (PIM1 to PIM6). Robust synthetic protocols were developed for utilizing bicyclic a...
Arun K. Mishra - One of the best experts on this subject based on the ideXlab platform.
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Mannan core branching of lipo(arabino)mannan is required for mycobacterial virulence in the context of innate immunity
Cellular Microbiology, 2013Co-Authors: Esther J M Stoop, Gunny Van Stempvoort, Pascale Bouchier, Theo Verboom, Marion Sparrius, Louise M. Van Leeuwen, S. A. Raadsen, Nicole N Driessen, Arun K. Mishra, Maaike Van ZonAbstract:The causative agent of tuberculosis (TB), Mycobacterium tuberculosis, remains an important worldwide health threat. Although TB is one of the oldest infectious diseases of man, a detailed understanding of the mycobacterial mechanisms underlying pathogenesis remains elusive. Here, we studied the role of the α(1→2) mannosyltransferase MptC in mycobacterial virulence, using the Mycobacterium marinum zebrafish infection model. Like its M. tuberculosis orthologue, disruption of M. marinum mptC (mmar_3225) results in defective elongation of mannose caps of lipoarabinomannan (LAM) and absence of α(1→2)mannose branches on the Lipomannan (LM) and LAM mannan core, as determined by biochemical analysis (NMR and GC-MS) and immunoblotting. We found that the M. marinum mptC mutant is strongly attenuated in embryonic zebrafish, which rely solely on innate immunity, whereas minor virulence defects were observed in adult zebrafish. Strikingly, complementation with the Mycobacterium smegmatis mptC orthologue, which restored mannan core branching but not cap elongation, was sufficient to fully complement the virulence defect of the mptC mutant in embryos. Altogether our data demonstrate that not LAM capping, but mannan core branching of LM/LAM plays an important role in mycobacterial pathogenesis in the context of innate immunity.
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Structure of the lipid anchor of bacterial macroamphiphiles.
2013Co-Authors: Landry Blanc, Arun K. Mishra, Gurdyal S Besra, Romain Castanier, Aurélie Ray, Iain Sutcliffe, Alain Vercellone, Jérôme NigouAbstract:CgLM, Corynebacterium glutamicum Lipomannan; DAG, diacylglycerol; FSL-1, synthetic N-terminal part of lipopoprotein LP44 of Mycoplasma salivarum; MlLM, Micrococcus luteus Lipomannan; MPI, mannosyl-phosphatidyl-myo-inositol; MsLM, Mycobacterium smegmatis Lipomannan; PGP, polyglycerolphosphate; SaLTA, Staphylococcus aureus lipoteichoic acid; The available evidence [29] suggests the structure of Stomatococcus mucilaginosus Lipomannan (SmLM) is very similar to that of MlLM.
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differential arabinan capping of lipoarabinomannan modulates innate immune responses and impacts t helper cell differentiation
Journal of Biological Chemistry, 2012Co-Authors: Arun K. Mishra, Karin Krumbach, Lothar Eggeling, Jérôme Nigou, Joana Alves, Antonio G Castro, Jeroen Geurtsen, Margarida Saraiva, Gurdyal S BesraAbstract:Toll-like receptors (TLRs) recognize pathogens by interacting with pathogen-associated molecular patterns, such as the phosphatidylinositol-based lipoglycans, Lipomannan (LM) and lipoarabinomannan (LAM). Such structures are present in several pathogens, including Mycobacterium tuberculosis, being important for the initiation of immune responses. It is well established that the interaction of LM and LAM with TLR2 is a process dependent on the structure of the ligands. However, the implications of structural variations on TLR2 ligands for the development of T helper (Th) cell responses or in the context of in vivo responses are less studied. Herein, we used Corynebacterium glutamicum as a source of lipoglycan intermediates for host interaction studies. In this study, we have deleted a putative glycosyltransferase, NCgl2096, from C. glutamicum and found that it encodes for a novel α(1→2)arabinofuranosyltransferase, AftE. Biochemical analysis of the lipoglycans obtained in the presence (wild type) or absence of NCgl2096 showed that AftE is involved in the biosynthesis of singular arabinans of LAM. In its absence, the resulting molecule is a hypermannosylated (hLM) form of LAM. Both LAM and hLM were recognized by dendritic cells, mainly via TLR2, and triggered the production of several cytokines. hLM was a stronger stimulus for in vitro cytokine production and, as a result, a more potent inducer of Th17 responses. In vivo data confirmed hLM as a stronger inducer of cytokine responses and suggested the involvement of pattern recognition receptors other than TLR2 as sensors for lipoglycans.
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deletion of manc in corynebacterium glutamicum results in a phospho myo inositol mannoside and lipoglycan deficient mutant
Microbiology, 2012Co-Authors: Arun K. Mishra, Sarah M Batt, Karin Krumbach, Gurdyal S Besra, Doris Rittmann, Oona Y C Lee, Julia Frunzke, Lothar EggelingAbstract:Mannose is an important constituent of the immunomodulatory glycoconjugates of the mycobacterial cell wall: lipoarabinomannan (LAM), Lipomannan (LM) and the related phospho-myo-inositol mannosides (PIMs). In Mycobacterium tuberculosis and the related bacillus Corynebacterium glutamicum, mannose is either imported from the medium or derived from glycolysis, and is subsequently converted into the nucleotide-based sugar donor guanosine diphosphomannose (GDP-mannose). This can be utilized by the glycosyltranferases of the GT-A/B superfamily or converted to the lipid-based donor polyprenyl monophosphomannose, and used as a substrate by the transmembrane glycosyltransferases of the GT-C superfamily. To investigate GDP-mannose biosynthesis in detail, the gene encoding a putative ManC in C. glutamicum was deleted. Deletion of manC resulted in a slow-growing mutant, with reduced but not totally abrogated guanosine diphosphomannose pyrophosphorylase activity. However, a comprehensive cell wall analysis revealed that C. glutamicumΔmanC is deficient in PIMs and LM/LAM. Closer inspection suggests that promiscuous ManC activity is contributed by additional putative nucleotidyltransferases, PmmB, WbbL1, GalU and GlmU, and a hypothetical protein, NCgl0715. Furthermore, complementation analyses of C. glutamicumΔmanC with Rv3264c suggested that it is a true homologue of ManC in M. tuberculosis, and the essentiality of PIMs in M. tuberculosis makes it an attractive drug target.
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lipoarabinomannan and related glycoconjugates structure biogenesis and role in mycobacterium tuberculosis physiology and host pathogen interaction
Fems Microbiology Reviews, 2011Co-Authors: Arun K. Mishra, Nicole N Driessen, Ben J Appelmelk, Gurdyal S BesraAbstract:Approximately one third of the world's population is infected with Mycobacterium tuberculosis, the causative agent of tuberculosis. This bacterium has an unusual lipid-rich cell wall containing a vast repertoire of antigens, providing a hydrophobic impermeable barrier against chemical drugs, thus representing an attractive target for vaccine and drug development. Apart from the mycolyl–arabinogalactan–peptidoglycan complex, mycobacteria possess several immunomodulatory constituents, notably Lipomannan and lipoarabinomannan. The availability of whole-genome sequences of M. tuberculosis and related bacilli over the past decade has led to the identification and functional characterization of various enzymes and the potential drug targets involved in the biosynthesis of these glycoconjugates. Both Lipomannan and lipoarabinomannan possess highly variable chemical structures, which interact with different receptors of the immune system during host–pathogen interactions, such as Toll-like receptors-2 and C-type lectins. Recently, the availability of mutants defective in the synthesis of these glycoconjugates in mycobacteria and the closely related bacterium, Corynebacterium glutamicum, has paved the way for host–pathogen interaction studies, as well as, providing attenuated strains of mycobacteria for the development of new vaccine candidates. This review provides a comprehensive account of the structure, biosynthesis and immunomodulatory properties of these important glycoconjugates.
Mary Jackson - One of the best experts on this subject based on the ideXlab platform.
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polysaccharide succinylation enhances the intracellular survival of mycobacterium abscessus
ACS Infectious Diseases, 2020Co-Authors: Zuzana Palcekova, Michael R Mcneil, Martine Gilleron, Shiva K Angala, Juan Manuel Belardinelli, Luiz E Bermudez, Mary JacksonAbstract:Lipoarabinomannan (LAM) and its biosynthetic precursors, phosphatidylinositol mannosides (PIMs) and Lipomannan (LM) play important roles in the interactions of Mycobacterium tuberculosis with phago...
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molecular basis of phosphatidyl myo inositol mannoside biosynthesis and regulation in mycobacteria
Journal of Biological Chemistry, 2010Co-Authors: Patrick J. Brennan, Marcelo E Guerin, Jana Kordulakova, Pedro M Alzari, Mary JacksonAbstract:Phosphatidyl-myo-inositol mannosides (PIMs) are unique glycolipids found in abundant quantities in the inner and outer membranes of the cell envelope of all Mycobacterium species. They are based on a phosphatidyl-myo-inositol lipid anchor carrying one to six mannose residues and up to four acyl chains. PIMs are considered not only essential structural components of the cell envelope but also the structural basis of the lipoglycans (Lipomannan and lipoarabinomannan), all important molecules implicated in host-pathogen interactions in the course of tuberculosis and leprosy. Although the chemical structure of PIMs is now well established, knowledge of the enzymes and sequential events leading to their biosynthesis and regulation is still incomplete. Recent advances in the identification of key proteins involved in PIM biogenesis and the determination of the three-dimensional structures of the essential phosphatidyl-myo-inositol mannosyltransferase PimA and the lipoprotein LpqW have led to important insights into the molecular basis of this pathway.
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NOTES Identification of a Polyprenylphosphomannosyl Synthase Involved in the Synthesis of Mycobacterial Mannosides†
2009Co-Authors: Hataichanok Scherman, Mary Jackson, Devinder Kaur, Ha Pham, Patrick J. BrennanAbstract: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
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the immunomodulatory lipoglycans lipoarabinomannan and Lipomannan are exposed at the mycobacterial cell surface
Tuberculosis, 2008Co-Authors: Sylvain Pitarque, Mary Jackson, Germain Puzo, Gerald Larrouymaumus, Bruno Payre, Jérôme NigouAbstract:By labeling surface carbohydrates, we found that a pool of lipoglycans, cell wall associated, is exposed at the cell surface of mycobacteria and thus, most probably, inserted in the outer leaflet of the outer membrane. In contrast, plasma membrane anchored lipoglycans are not accessible to surface labeling. This result supports the role of lipoglycans as key immunomodulatory molecules but raises the question of their transport from the plasma membrane, where they are synthesized, to the outermost layers of the envelope, where they can act as modulins. The data are discussed in terms of consequences for cell envelope organization.
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new insights into the biosynthesis of mycobacterial Lipomannan arising from deletion of a conserved gene
Journal of Biological Chemistry, 2007Co-Authors: Devinder Kaur, Kayhooi Khoo, Delphi Chatterjee, Michael R Mcneil, Dean C Crick, Mary Jackson, Patrick J. BrennanAbstract: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.