1
|
Agarwal K, Choudhury B, Robinson LS, Morrill SR, Bouchibiti Y, Chilin-Fuentes D, Rosenthal SB, Fisch KM, Peipert JF, Lebrilla CB, Allsworth JE, Lewis AL, Lewis WG. Resident microbes shape the vaginal epithelial glycan landscape. Sci Transl Med 2023; 15:eabp9599. [PMID: 38019934 PMCID: PMC11419735 DOI: 10.1126/scitranslmed.abp9599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 11/01/2023] [Indexed: 12/01/2023]
Abstract
Epithelial cells are covered in carbohydrates (glycans). This glycan coat or "glycocalyx" interfaces directly with microbes, providing a protective barrier against potential pathogens. Bacterial vaginosis (BV) is a condition associated with adverse health outcomes in which bacteria reside in direct proximity to the vaginal epithelium. Some of these bacteria, including Gardnerella, produce glycosyl hydrolase enzymes. However, glycans of the human vaginal epithelial surface have not been studied in detail. Here, we elucidate key characteristics of the "normal" vaginal epithelial glycan landscape and analyze the impact of resident microbes on the surface glycocalyx. In human BV, glycocalyx staining was visibly diminished in electron micrographs compared to controls. Biochemical and mass spectrometric analysis showed that, compared to normal vaginal epithelial cells, BV cells were depleted of sialylated N- and O-glycans, with underlying galactose residues exposed on the surface. Treatment of primary epithelial cells from BV-negative women with recombinant Gardnerella sialidases generated BV-like glycan phenotypes. Exposure of cultured VK2 vaginal epithelial cells to recombinant Gardnerella sialidase led to desialylation of glycans and induction of pathways regulating cell death, differentiation, and inflammatory responses. These data provide evidence that vaginal epithelial cells exhibit an altered glycan landscape in BV and suggest that BV-associated glycosidic enzymes may lead to changes in epithelial gene transcription that promote cell turnover and regulate responses toward the resident microbiome.
Collapse
Affiliation(s)
- Kavita Agarwal
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, United States of America
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110, United States of America
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Diego (UCSD), La Jolla, CA 92093, United States of America
- Glycobiology Research and Training Center, UCSD, La Jolla, CA 92093, United States of America
| | - Biswa Choudhury
- Glycobiology Research and Training Center, UCSD, La Jolla, CA 92093, United States of America
| | - Lloyd S. Robinson
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, United States of America
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110, United States of America
| | - Sydney R. Morrill
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, United States of America
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110, United States of America
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Diego (UCSD), La Jolla, CA 92093, United States of America
- Glycobiology Research and Training Center, UCSD, La Jolla, CA 92093, United States of America
| | - Yasmine Bouchibiti
- Department of Chemistry, University of California, Davis, Davis, CA 95616, United States of America
- Department of Food Science and Technology, University of California, Davis, Davis, CA 95616, United States of America
| | - Daisy Chilin-Fuentes
- Center for Computational Biology & Bioinformatics, UCSD, La Jolla, CA 92093, United States of America
| | - Sara B. Rosenthal
- Center for Computational Biology & Bioinformatics, UCSD, La Jolla, CA 92093, United States of America
| | - Kathleen M. Fisch
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Diego (UCSD), La Jolla, CA 92093, United States of America
- Center for Computational Biology & Bioinformatics, UCSD, La Jolla, CA 92093, United States of America
| | - Jeffrey F. Peipert
- Department of Obstetrics and Gynecology, Indiana University School of Medicine, Indianapolis, IN 46202, United States of America
| | - Carlito B. Lebrilla
- Department of Chemistry, University of California, Davis, Davis, CA 95616, United States of America
- Department of Food Science and Technology, University of California, Davis, Davis, CA 95616, United States of America
| | - Jenifer E. Allsworth
- Department of Biomedical and Health Informatics, University of Missouri, Kansas City School of Medicine, Kansas City, MO 64110, United States of America
| | - Amanda L. Lewis
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, United States of America
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110, United States of America
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Diego (UCSD), La Jolla, CA 92093, United States of America
- Glycobiology Research and Training Center, UCSD, La Jolla, CA 92093, United States of America
| | - Warren G. Lewis
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, United States of America
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110, United States of America
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Diego (UCSD), La Jolla, CA 92093, United States of America
- Glycobiology Research and Training Center, UCSD, La Jolla, CA 92093, United States of America
| |
Collapse
|
2
|
Scaletti ER, Pettersson P, Patrick J, Shilling PJ, Westergren RG, Daley DO, Mäler L, Widmalm G, Stenmark P. Structural and functional insights into the Pseudomonas aeruginosa glycosyltransferase WaaG and the implications for lipopolysaccharide biosynthesis. J Biol Chem 2023; 299:105256. [PMID: 37716703 PMCID: PMC10579960 DOI: 10.1016/j.jbc.2023.105256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/31/2023] [Accepted: 09/10/2023] [Indexed: 09/18/2023] Open
Abstract
The glycosyltransferase WaaG in Pseudomonas aeruginosa (PaWaaG) is involved in the synthesis of the core region of lipopolysaccharides. It is a promising target for developing adjuvants that could help in the uptake of antibiotics. Herein, we have determined structures of PaWaaG in complex with the nucleotide-sugars UDP-glucose, UDP-galactose, and UDP-GalNAc. Structural comparison with the homolog from Escherichia coli (EcWaaG) revealed five key differences in the sugar-binding pocket. Solution-state NMR analysis showed that WT PaWaaG specifically hydrolyzes UDP-GalNAc and unlike EcWaaG, does not hydrolyze UDP-glucose. Furthermore, we found that a PaWaaG mutant (Y97F/T208R/N282A/T283A/T285I) designed to resemble the EcWaaG sugar binding site, only hydrolyzed UDP-glucose, underscoring the importance of the identified amino acids in substrate specificity. However, neither WT PaWaaG nor the PaWaaG mutant capable of hydrolyzing UDP-glucose was able to complement an E. coli ΔwaaG strain, indicating that more remains to be uncovered about the function of PaWaaG in vivo. This structural and biochemical information will guide future structure-based drug design efforts targeting PaWaaG.
Collapse
Affiliation(s)
- Emma R Scaletti
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Pontus Pettersson
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Joan Patrick
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Patrick J Shilling
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | | | - Daniel O Daley
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Lena Mäler
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
| |
Collapse
|
3
|
Kenyon JJ, Hall RM. Variation in the complex carbohydrate biosynthesis loci of Acinetobacter baumannii genomes. PLoS One 2013; 8:e62160. [PMID: 23614028 PMCID: PMC3628348 DOI: 10.1371/journal.pone.0062160] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Accepted: 03/19/2013] [Indexed: 01/16/2023] Open
Abstract
Extracellular polysaccharides are major immunogenic components of the bacterial cell envelope. However, little is known about their biosynthesis in the genus Acinetobacter, which includes A. baumannii, an important nosocomial pathogen. Whether Acinetobacter sp. produce a capsule or a lipopolysaccharide carrying an O antigen or both is not resolved. To explore these issues, genes involved in the synthesis of complex polysaccharides were located in 10 complete A. baumannii genome sequences, and the function of each of their products was predicted via comparison to enzymes with a known function. The absence of a gene encoding a WaaL ligase, required to link the carbohydrate polymer to the lipid A-core oligosaccharide (lipooligosaccharide) forming lipopolysaccharide, suggests that only a capsule is produced. Nine distinct arrangements of a large capsule biosynthesis locus, designated KL1 to KL9, were found in the genomes. Three forms of a second, smaller variable locus, likely to be required for synthesis of the outer core of the lipid A-core moiety, were designated OCL1 to OCL3 and also annotated. Each K locus includes genes for capsule export as well as genes for synthesis of activated sugar precursors, and for glycosyltransfer, glycan modification and oligosaccharide repeat-unit processing. The K loci all include the export genes at one end and genes for synthesis of common sugar precursors at the other, with a highly variable region that includes the remaining genes in between. Five different capsule loci, KL2, KL6, KL7, KL8 and KL9 were detected in multiply antibiotic resistant isolates belonging to global clone 2, and two other loci, KL1 and KL4, in global clone 1. This indicates that this region is being substituted repeatedly in multiply antibiotic resistant isolates from these clones.
Collapse
Affiliation(s)
- Johanna J. Kenyon
- School of Molecular Bioscience, The University of Sydney, Sydney, New South Wales, Australia
| | - Ruth M. Hall
- School of Molecular Bioscience, The University of Sydney, Sydney, New South Wales, Australia
- * E-mail:
| |
Collapse
|
4
|
Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2007-2008. MASS SPECTROMETRY REVIEWS 2012; 31:183-311. [PMID: 21850673 DOI: 10.1002/mas.20333] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 01/04/2011] [Accepted: 01/04/2011] [Indexed: 05/31/2023]
Abstract
This review is the fifth update of the original review, published in 1999, on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2008. The first section of the review covers fundamental studies, fragmentation of carbohydrate ions, use of derivatives and new software developments for analysis of carbohydrate spectra. Among newer areas of method development are glycan arrays, MALDI imaging and the use of ion mobility spectrometry. The second section of the review discusses applications of MALDI MS to the analysis of different types of carbohydrate. Specific compound classes that are covered include carbohydrate polymers from plants, N- and O-linked glycans from glycoproteins, biopharmaceuticals, glycated proteins, glycolipids, glycosides and various other natural products. There is a short section on the use of MALDI mass spectrometry for the study of enzymes involved in glycan processing and a section on the use of MALDI MS to monitor products of the chemical synthesis of carbohydrates with emphasis on carbohydrate-protein complexes and glycodendrimers. Corresponding analyses by electrospray ionization now appear to outnumber those performed by MALDI and the amount of literature makes a comprehensive review on this technique impractical. However, most of the work relating to sample preparation and glycan synthesis is equally relevant to electrospray and, consequently, those proposing analyses by electrospray should also find material in this review of interest.
Collapse
Affiliation(s)
- David J Harvey
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
| |
Collapse
|
6
|
Lam JS, Taylor VL, Islam ST, Hao Y, Kocíncová D. Genetic and Functional Diversity of Pseudomonas aeruginosa Lipopolysaccharide. Front Microbiol 2011; 2:118. [PMID: 21687428 PMCID: PMC3108286 DOI: 10.3389/fmicb.2011.00118] [Citation(s) in RCA: 186] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 05/12/2011] [Indexed: 12/13/2022] Open
Abstract
Lipopolysccharide (LPS) is an integral component of the Pseudomonas aeruginosa cell envelope, occupying the outer leaflet of the outer membrane in this Gram-negative opportunistic pathogen. It is important for bacterium-host interactions and has been shown to be a major virulence factor for this organism. Structurally, P. aeruginosa LPS is composed of three domains, namely, lipid A, core oligosaccharide, and the distal O antigen (O-Ag). Most P. aeruginosa strains produce two distinct forms of O-Ag, one a homopolymer of D-rhamnose that is a common polysaccharide antigen (CPA, formerly termed A band), and the other a heteropolymer of three to five distinct (and often unique dideoxy) sugars in its repeat units, known as O-specific antigen (OSA, formerly termed B band). Compositional differences in the O units among the OSA from different strains form the basis of the International Antigenic Typing Scheme for classification via serotyping of different strains of P. aeruginosa. The focus of this review is to provide state-of-the-art knowledge on the genetic and resultant functional diversity of LPS produced by P. aeruginosa. The underlying factors contributing to this diversity will be thoroughly discussed and presented in the context of its contributions to host-pathogen interactions and the control/prevention of infection.
Collapse
Affiliation(s)
- Joseph S. Lam
- Department of Molecular and Cellular Biology, University of GuelphGuelph, ON, Canada
| | - Véronique L. Taylor
- Department of Molecular and Cellular Biology, University of GuelphGuelph, ON, Canada
| | - Salim T. Islam
- Department of Molecular and Cellular Biology, University of GuelphGuelph, ON, Canada
| | - Youai Hao
- Department of Molecular and Cellular Biology, University of GuelphGuelph, ON, Canada
| | - Dana Kocíncová
- Department of Molecular and Cellular Biology, University of GuelphGuelph, ON, Canada
| |
Collapse
|
7
|
Abstract
Bacterial lipopolysaccharides (LPSs) are the major component of the outer membrane of Gram-negative bacteria. They have a structural role since they contribute to the cellular rigidity by increasing the strength of cell wall and mediating contacts with the external environment that can induce structural changes to allow life in different conditions. Furthermore, the low permeability of the outer membrane acts as a barrier to protect bacteria from host-derived antimicrobial compounds. Lipopolysaccharides are amphiphilic macromolecules generally comprising three defined regions distinguished by their genetics, structures and function: the lipid A, the core oligosaccharide and a polysaccharide portion, the O-chain. In some Gram-negative bacteria LPS can terminate with the core portion to form rough type LPS (R-LPS, LOS). The core oligosaccharide is an often branched and phosphorylated heterooligosaccharide with less than fifteen sugars, more conserved in the inner region, proximal to the lipid A, and often carrying non-stoichiometric substitutions leading to variation and micro-heterogeneity. The core oligosaccharide contributes to the bacterial viability and stability of the outer membrane, can assure the serological specificity and possesses antigenic properties.
Collapse
|
8
|
King JD, Kocíncová D, Westman EL, Lam JS. Review: Lipopolysaccharide biosynthesis in Pseudomonas aeruginosa. Innate Immun 2009; 15:261-312. [PMID: 19710102 DOI: 10.1177/1753425909106436] [Citation(s) in RCA: 229] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Pseudomonas aeruginosa causes serious nosocomial infections, and an important virulence factor produced by this organism is lipopolysaccharide (LPS). This review summarizes knowledge about biosynthesis of all three structural domains of LPS - lipid A, core oligosaccharide, and O polysaccharides. In addition, based on similarities with other bacterial species, this review proposes new hypothetical pathways for unstudied steps in the biosynthesis of P. aeruginosa LPS. Lipid A biosynthesis is discussed in relation to Escherichia coli and Salmonella, and the biosyntheses of core sugar precursors and core oligosaccharide are summarised. Pseudomonas aeruginosa attaches a Common Polysaccharide Antigen and O-Specific Antigen polysaccharides to lipid A-core. Both forms of O polysaccharide are discussed with respect to their independent synthesis mechanisms. Recent advances in understanding O-polysaccharide biosynthesis since the last major review on this subject, published nearly a decade ago, are highlighted. Since P. aeruginosa O polysaccharides contain unusual sugars, sugar-nucleotide biosynthesis pathways are reviewed in detail. Knowledge derived from detailed studies in the O5, O6 and O11 serotypes is applied to predict biosynthesis pathways of sugars in poorly-studied serotypes, especially O1, O4, and O13/O14. Although further work is required, a full understanding of LPS biosynthesis in P. aeruginosa is almost within reach.
Collapse
Affiliation(s)
- Jerry D King
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | | | | | | |
Collapse
|