Publications
98 results found
Rycroft J, Gollan B, Grabe G, et al., 2018, Activity of acetyltransferase toxins involved in Salmonella persister formation during macrophage infection, Nature Communications, Vol: 9, ISSN: 2041-1723
Non-typhoidal Salmonella strains are responsible for invasive infections associated withhigh mortality and recurrence in sub-Saharan Africa and there is strong evidence for clonalrelapse following antibiotic treatment. Persisters are non-growing bacteria that are thought tobe responsible for the recalcitrance of many infections to antibiotics. Toxin-antitoxin systemsare stress-responsive elements that are important for Salmonella persister formation,specifically during infection. Here we report analysis of persister formation of clinical invasive strains of S. Typhimurium and Enteritidis in human primary macrophages. We show that allthe invasive clinical isolates of both serovars that we tested produce high levels of persisters following internalization by human macrophages. Our genome comparison reveals that S.Enteritidis and S. Typhimurium strains contain three acetyltransferase toxins that we characterize structurally and functionally. We show that all induce the persister state byinhibiting translation through acetylation of aminoacyl-tRNAs. However, they differ in theirpotency and target partially different subsets of aminoacyl-tRNAs, potentially accounting fortheir non-redundant effect.
Grabe GJ, Rycroft JA, Gollan B, et al., 2018, Crystal structure of TacT3 (tRNA acetylating toxin) from Salmonella
Lobato-Marquez D, Krokowski S, Sirianni A, et al., 2018, A requirement for septins and the autophagy receptor p62 in the proliferation of intracellular Shigella, Cytoskeleton, Vol: 76, Pages: 163-172, ISSN: 1949-3584
Shigella flexneri, a Gram‐negative enteroinvasive pathogen, causes inflammatory destruction of the human intestinal epithelium. During infection of epithelial cells, Shigella escape from the phagosome to the cytosol, where they reroute host cell glycolysis to obtain nutrients for proliferation. Septins, a poorly understood component of the cytoskeleton, can entrap cytosolic Shigella targeted to autophagy in cage‐like structures to restrict bacterial proliferation. Although bacterial entrapment by septin caging has been the subject of intense investigation, the role of septins and the autophagy machinery in the proliferation of non‐caged Shigella is mostly unknown. Here, we found that intracellular Shigella fail to efficiently proliferate in SEPT2‐, SEPT7‐ or p62/SQSTM1‐depleted cells. Consistent with a failure to proliferate, single cell analysis of bacteria not entrapped in septin cages showed that the number of metabolically active Shigella in septin‐ or p62‐depleted cells is reduced. Targeted metabolomic analysis revealed that host cell glycolysis is dysregulated in septin‐depleted cells, suggesting a key role for septins in modulation of glycolysis. Together, these results suggest that septins and the autophagy machinery may regulate metabolic pathways that promote the proliferation intracellular Shigella not entrapped in septin cages.
Berger C, Crepin V, Roumeliotis TI, et al., 2017, Citrobacter rodentium subverts ATP flux 1 and cholesterol homeostasis in 2 intestinal epithelial cell in vivo, Cell Metabolism, Vol: 26, Pages: 738-752.e6, ISSN: 1550-4131
The intestinal epithelial cells (IECs) that line the gut form a robust line of defense against ingested pathogens. We investigated the impact of infection with the enteric pathogen Citrobacter rodentium on mouse IEC metabolism using global proteomic and targeted metabolomics and lipidomics. The major signatures of the infection were upregulation of the sugar transporter Sglt4, aerobic glycolysis, and production of phosphocreatine, which mobilizes cytosolic energy. In contrast, biogenesis of mitochondrial cardiolipins, essential for ATP production, was inhibited, which coincided with increased levels of mucosal O2 and a reduction in colon-associated anaerobic commensals. In addition, IECs responded to infection by activating Srebp2 and the cholesterol biosynthetic pathway. Unexpectedly, infected IECs also upregulated the cholesterol efflux proteins AbcA1, AbcG8, and ApoA1, resulting in higher levels of fecal cholesterol and a bloom of Proteobacteria. These results suggest that C. rodentium manipulates host metabolism to evade innate immune responses and establish a favorable gut ecosystem.
Robert CB, Thomson M, Vercellone A, et al., 2017, Mass spectrometry analysis of intact <i>Francisella</i> bacteria identifies lipid A structure remodeling in response to acidic pH stress, BIOCHIMIE, Vol: 141, Pages: 16-20, ISSN: 0300-9084
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- Citations: 12
Buchieri MV, Cimino M, Rebollo-Ramirez S, et al., 2017, Nitazoxanide Analogs Require Nitroreduction for Antimicrobial Activity in Mycobacterium smegmatis, JOURNAL OF MEDICINAL CHEMISTRY, Vol: 60, Pages: 7425-7433, ISSN: 0022-2623
Pacholarz KJ, Burnley RJ, Jowitt TA, et al., 2017, Hybrid Mass Spectrometry Approaches to Determine How L-Histidine Feedback Regulates the Enzyzme MtATP-Phosphoribosyltransferase, Structure, Vol: 25, Pages: 730-738.e4, ISSN: 1878-4186
MtATP-phosphoribosyltransferase (MtATP-PRT) is an enzyme catalyzing the first step of the biosynthesis of L-histidine in Mycobacterium tuberculosis, and proposed to be regulated via an allosteric mechanism. Native mass spectrometry (MS) reveals MtATP-PRT to exist as a hexamer. Conformational changes induced by L-histidine binding and the influence of buffer pH are determined with ion mobility MS, hydrogen deuterium exchange (HDX) MS, and analytical ultracentrifugation. The experimental collision cross-section (DTCCSHe) decreases from 76.6 to 73.5 nm2 upon ligand binding at pH 6.8, which correlates to the decrease in CCS calculated from crystal structures. No such changes in conformation were found at pH 9.0. Further detail on the regions that exhibit conformational change on L-histidine binding is obtained with HDX-MS experiments. On incubation with L-histidine, rapid changes are observed within domain III, and around the active site at longer times, indicating an allosteric effect.
Larrouy-Maumus G, Layre E, Clark S, et al., 2017, Protective efficacy of a lipid antigen vaccine in a guinea pig model of tuberculosis, VACCINE, Vol: 35, Pages: 1395-1402, ISSN: 0264-410X
Sirianni A, Krokowski S, Lobato-Márquez D, et al., 2016, Mitochondria mediate septin cage assembly to promote autophagy of Shigella, EMBO Reports, Vol: 17, Pages: 1-15, ISSN: 1469-221X
Septins, cytoskeletal proteins with well-characterised roles in cytokinesis, form cage-like structures around cytosolic Shigella flexneri and promote their targeting to autophagosomes. However, the processes underlying septin cage assembly, and whether they influence S. flexneri proliferation, remain to be established. Using single cell analysis, we show that septin cages inhibit S. flexneri proliferation. To study mechanisms of septin cage assembly, we used proteomics and found mitochondrial proteins associate with septins in S. flexneriinfected cells. Strikingly, mitochondria associated with S. flexneri promote septin assembly into the cages that entrap bacteria for autophagy. We demonstrate that the cytosolic GTPase dynamin-related protein 1 (Drp1) interacts with septins to enhance mitochondrial fission. To avoid autophagy, actin-polymerising Shigella fragment mitochondria to escape from septin caging. Our results have demonstrated a role for mitochondria in anti-Shigella autophagy, and uncovered a fundamental link between septin assembly and mitochondria.
Larrouy-Maumus GJ, Leonardo B Marino, Ashoka V R Madduri, et al., 2016, Cell-Envelope Remodeling as a Determinant of Phenotypic Antibacterial Tolerance in Mycobacterium tuberculosis, ACS Infectious Diseases, Vol: 2, Pages: 352-360, ISSN: 2373-8227
The mechanisms that lead to phenotypic antibacterial tolerance in bacteria remain poorly understood. We investigate whether changes in NaCl concentration toward physiologically higher values affect antibacterial efficacy against Mycobacterium tuberculosis (Mtb), the causal agent of human tuberculosis. Indeed, multiclass phenotypic antibacterial tolerance is observed during Mtb growth in physiologic saline. This includes changes in sensitivity to ethionamide, ethambutol, d-cycloserine, several aminoglycosides, and quinolones. By employing organism-wide metabolomic and lipidomic approaches combined with phenotypic tests, we identified a time-dependent biphasic adaptive response after exposure of Mtb to physiological levels of NaCl. A first rapid, extensive, and reversible phase was associated with changes in core and amino acid metabolism. In a second phase, Mtb responded with a substantial remodelling of plasma membrane and outer lipid membrane composition. We demonstrate that phenotypic tolerance at physiological concentrations of NaCl is the result of changes in plasma and outer membrane lipid remodeling and not changes in core metabolism. Altogether, these results indicate that physiologic saline-induced antibacterial tolerance is kinetically coupled to cell envelope changes and demonstrate that metabolic changes and growth arrest are not the cause of phenotypic tolerance observed in Mtb exposed to physiologic concentrations of NaCl. Importantly, this work uncovers a role for bacterial cell envelope remodeling in antibacterial tolerance, alongside well-documented allterations in respiration, metabolism, and growth rate.
Larrouy-Maumus GJ, Abigail Clements, Alain Filloux, et al., 2015, Direct detection of lipid A on intact Gram-negative bacteria byMALDI-TOF mass spectrometry, Journal of Microbiological Methods, Vol: 120, Pages: 68-71, ISSN: 1872-8359
The purification and characterization of Gram-negative bacterial lipid A is tedious and time-consuming. Herein we report a rapid and sensitive method to identify lipid A directly on intact bacteria without any chemical treatment or purification, using an atypical solvent system to solubilize the matrix combined with MALDI-TOF mass spectrometry.
Larrouy-Maumus GJ, Gilleron M, Skovierova H, et al., 2015, A glycomic approach reveals a new mycobacterial polysaccharide, Glycobiology, Vol: 25, Pages: 1163-1171, ISSN: 1460-2423
Mycobacterium tuberculosis lipoarabinomannan (LAM) and biosynthetically related lipoglycans and glycans play an important role in host–pathogen interactions. Therefore, the elucidation of the complete biosynthetic pathways of these important molecules is expected to afford novel therapeutic targets. The characterization of biosynthetic enzymes and transporters involved in the formation and localization of these complex macromolecules in the bacterial cell envelope largely relies on genetic manipulation of mycobacteria and subsequent analyses of lipoglycan structural alterations. However, lipoglycans are present in relatively low amounts. Their purification to homogeneity remains tedious and time-consuming. To overcome these issues and to reduce the biomass and time required for lipoglycan purification, we report here the development of a methodology to efficiently purify lipoglycans by sodium deoxycholate–polyacrylamide gel electrophoresis. This faster purification method can be applied on a small amount of mycobacterial cells biomass (10–50 mg), resulting in tens of micrograms of purified lipoglycans. This amount of purified products was found to be sufficient to undertake structural analyses of lipoglycans and glycans carbohydrate domains by a combination of highly sensitive analytical procedures, involving cryoprobe NMR analysis of intact macromolecules and chemical degradations monitored by gas chromatography and capillary electrophoresis. This glycomic approach was successfully applied to the purification and structural characterization of a newly identified polysaccharide, structurally related to LAM, in the model fast-growing species Mycobacterium smegmatis.
Wheat WH, Dhouib R, Angala SK, et al., 2015, The presence of a galactosamine substituent on the arabinogalactan of <i>Mycobacterium tuberculosis</i> abrogates full maturation of human peripheral blood monocyte-derived dendritic cells and increases secretion of IL-10, TUBERCULOSIS, Vol: 95, Pages: 476-489, ISSN: 1472-9792
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- Citations: 10
Larrouy-Maumus GJ, 2015, Cholesterol acquisition by Mycobacterium tuberculosis, Virulence, ISSN: 2150-5608
Larrouy-Maumus G, Puzo G, 2015, Mycobacterial envelope lipids fingerprint from direct MALDI-TOF MS analysis of intact bacilli, TUBERCULOSIS, Vol: 95, Pages: 75-85, ISSN: 1472-9792
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- Citations: 22
Belardinelli JM, Larrouy-Maumus G, Jones V, et al., 2014, Biosynthesis and Translocation of Unsulfated Acyltrehaloses in Mycobacterium tuberculosis, Journal of Biological Chemistry, Vol: 289, Pages: 27952-27965, ISSN: 1083-351X
Prosser GA, Larrouy-Maumus G, de Carvalho LPS, 2014, Metabolomic strategies for the identification of new enzyme functions and metabolic pathways, EMBO REPORTS, Vol: 15, Pages: 657-669, ISSN: 1469-221X
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- Citations: 76
Gouzy A, Larrouy-Maumus G, Wu T-D, et al., 2014, <i>Mycobacterium tuberculosis</i> nitrogen assimilation and host colonization require aspartate (vol 9, pg 674, 2013), NATURE CHEMICAL BIOLOGY, Vol: 10, Pages: 164-164, ISSN: 1552-4450
Gouzy A, Larrouy-Maumus G, Bottai D, et al., 2014, <i>Mycobacterium tuberculosis</i> Exploits Asparagine to Assimilate Nitrogen and Resist Acid Stress during Infection, PLOS PATHOGENS, Vol: 10, ISSN: 1553-7366
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- Citations: 114
Larrouy-Maumus G, Kelly G, de Carvalho LPS, 2014, Chemical Mechanism of Glycerol 3-Phosphate Phosphatase: pH-Dependent Changes in the Rate-Limiting Step, BIOCHEMISTRY, Vol: 53, Pages: 143-151, ISSN: 0006-2960
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- Citations: 1
Gouzy A, Larrouy-Maumus G, Wu T-D, et al., 2013, <i>Mycobacterium tuberculosis</i> nitrogen assimilation and host colonization require aspartate, NATURE CHEMICAL BIOLOGY, Vol: 9, Pages: 674-+, ISSN: 1552-4450
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- Citations: 74
Biswas T, Larrouy-Maumus G, de Carvalho LP, et al., 2013, Crystal structure of glycerol phosphate phosphatase Rv1692 from Mycobacterium tuberculosis in complex with magnesium
Biswas T, Larrouy-Maumus G, de Carvalho LP, et al., 2013, Crystal structure of glycerol phosphate phosphatase Rv1692 from Mycobacterium tuberculosis in complex with calcium
Larrouy-Maumus G, Biswas T, Hunt DM, et al., 2013, Discovery of a glycerol 3-phosphate phosphatase reveals glycerophospholipid polar head recycling in <i>Mycobacterium tuberculosis</i>, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 110, Pages: 11320-11325, ISSN: 0027-8424
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- Citations: 41
Mao C, Shukla M, Larrouy-Maumus G, et al., 2013, Functional assignment of <i>Mycobacterium tuberculosis</i> proteome revealed by genome-scale fold-recognition, TUBERCULOSIS, Vol: 93, Pages: 40-46, ISSN: 1472-9792
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- Citations: 11
Larrouy-Maumus G, Skovierova H, Dhouib R, et al., 2012, A Small Multidrug Resistance-like Transporter Involved in the Arabinosylation of Arabinogalactan and Lipoarabinomannan in Mycobacteria, JOURNAL OF BIOLOGICAL CHEMISTRY, Vol: 287
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- Citations: 19
Pedreno S, Pisco JP, Larrouy-Maumus G, et al., 2012, Mechanism of Feedback Allosteric Inhibition of ATP Phosphoribosyltransferase, BIOCHEMISTRY, Vol: 51, Pages: 8027-8038, ISSN: 0006-2960
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- Citations: 27
Jackson M, Dhouib R, Skovierova H, et al., 2012, Biogenesis of mycobacterial cell envelope glycoconjugates, Experimental Biology Meeting, Publisher: FEDERATION AMER SOC EXP BIOL, ISSN: 0892-6638
Krishna S, Ray A, Dubey SK, et al., 2011, Lipoglycans Contribute to Innate Immune Detection of Mycobacteria, PLOS ONE, Vol: 6, ISSN: 1932-6203
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- Citations: 13
Cot M, Ray A, Gilleron M, et al., 2011, Lipoteichoic Acid in <i>Streptomyces hygroscopicus</i>: Structural Model and Immunomodulatory Activities, PLOS ONE, Vol: 6, ISSN: 1932-6203
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- Citations: 17
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