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Sousa LGV, Novak J, França A, Muzny CA, Cerca N. Gardnerella vaginalis, Fannyhessea vaginae, and Prevotella bivia Strongly Influence Each Other's Transcriptome in Triple-Species Biofilms. MICROBIAL ECOLOGY 2024; 87:117. [PMID: 39294302 PMCID: PMC11410844 DOI: 10.1007/s00248-024-02433-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Accepted: 09/04/2024] [Indexed: 09/20/2024]
Abstract
Bacterial vaginosis (BV), the most common vaginal infection worldwide, is characterized by the development of a polymicrobial biofilm on the vaginal epithelium. While Gardnerella spp. have been shown to have a prominent role in BV, little is known regarding how other species can influence BV development. Thus, we aimed to study the transcriptome of Gardnerella vaginalis, Fannyhessea vaginae, and Prevotella bivia, when growing in triple-species biofilms. Single and triple-species biofilms were formed in vitro, and RNA was extracted and sent for sequencing. cDNA libraries were prepared and sequenced. Quantitative PCR analysis (qPCR) was performed on the triple-species biofilms to evaluate the biofilm composition. The qPCR results revealed that the triple-species biofilms were mainly composed by G. vaginalis and P. bivia was the species with the lowest percentage. The RNA-sequencing analysis revealed a total of 432, 126, and 39 differentially expressed genes for G. vaginalis, F. vaginae, and P. bivia, respectively, when growing together. Gene ontology enrichment of G. vaginalis downregulated genes revealed several functions associated with metabolism, indicating a low metabolic activity of G. vaginalis when growing in polymicrobial biofilms. This work highlighted that the presence of 3 different BV-associated bacteria in the biofilm influenced each other's transcriptome and provided insight into the molecular mechanisms that enhanced the virulence potential of polymicrobial consortia. These findings will contribute to understand the development of incident BV and the interactions occurring within the biofilm.
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Affiliation(s)
- Lúcia G V Sousa
- Centre of Biological Engineering (CEB), Laboratory of Research in Biofilms Rosário Oliveira (LIBRO), University of Minho, Braga, Portugal
| | - Juliano Novak
- Centre of Biological Engineering (CEB), Laboratory of Research in Biofilms Rosário Oliveira (LIBRO), University of Minho, Braga, Portugal
- Botucatu Medical School, Department of Pathology, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Angela França
- Centre of Biological Engineering (CEB), Laboratory of Research in Biofilms Rosário Oliveira (LIBRO), University of Minho, Braga, Portugal
- LABBELS - Associate Laboratory, Braga, Portugal
| | - Christina A Muzny
- Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nuno Cerca
- Centre of Biological Engineering (CEB), Laboratory of Research in Biofilms Rosário Oliveira (LIBRO), University of Minho, Braga, Portugal.
- LABBELS - Associate Laboratory, Braga, Portugal.
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2
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Shi Z, Wei X, Wei Y, Zhang Z, Wan S, Gao H, Qin Z. Biochemical properties and application of a multi-domain β-1,3-1,4-glucanase from Fibrobacter sp. Int J Biol Macromol 2024; 273:133026. [PMID: 38852722 DOI: 10.1016/j.ijbiomac.2024.133026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/30/2024] [Accepted: 06/06/2024] [Indexed: 06/11/2024]
Abstract
A novel glycoside hydrolase (GH) family 16 multi-domain β-1,3-1,4-glucanase (FsGlc16A) from Fibrobacter sp. UWP2 was identified, heterogeneously expressed, and its enzymatic properties, protein structure and application potential were characterized. Enzymological characterization showed that FsGlc16A performed the optimal catalytic activity at pH 4.5 and 50 °C with a specific activity of 3263 U/mg. FsGlc16A exhibited the substrate specificity towards oat β-glucan, barley β-glucan and lichenan, and in addition, it hydrolyzed oat β-glucan and lichenan into different β-glucooligosaccharides with polymerization degrees of 3-4, which further illustrated that it belonged to the endo-type β-1,3-1,4-glucanase. FsGlc16A was classified in subfamily25 of GH16. A 'PXSSSS' repeats domain was identified at the C-terminus of FsGlc16A, which was distinct from the typical GH family 16 β-1,3-1,4-glucanases. Removing the 'PXSSSS' repeats domain affected the binding of the substrate to FsGlc16A and reduced the enzyme activity. FsGlc16A displayed good potential for the applications, which hydrolyzed oat bran into β-glucooligosaccharides, and reduced filtration time (18.89 %) and viscosity (3.64 %) in the saccharification process. This study investigated the enzymatic properties and domain function of FsGlc16A, providing new ideas and insights into the study of β-1,3-1,4-glucanase.
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Affiliation(s)
- Zhongyu Shi
- School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Xiasen Wei
- School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Yunfan Wei
- School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Zheyi Zhang
- School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Sibao Wan
- School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Haiyan Gao
- School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Zhen Qin
- School of Life Sciences, Shanghai University, Shanghai 200444, China.
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3
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Sharma SP, Purcell CM, Hyde JR, Severin AJ. Spirochaete genome identified in red abalone sample represents a novel genus Candidatus Haliotispira gen. nov. within the order Spirochaetales. Int J Syst Evol Microbiol 2024; 74. [PMID: 38179990 DOI: 10.1099/ijsem.0.006198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024] Open
Abstract
A fully assembled spirochaete genome was identified as a contaminating scaffold in our red abalone (Haliotis rufescens) genome assembly. In this paper, we describe the analysis of this bacterial genome. The assembled spirochaete genome is 3.25 Mb in size with 48.5 mol% G+C content. The proteomes of 38 species were compared with the spirochaete genome and it was discovered to form an independent branch within the family Spirochaetaceae on the phylogenetic tree. The comparison of 16S rRNA sequences and average nucleotide identity scores between the spirochaete genome with known species of different families in Spirochaetia indicate that it is an unknown species. Further, the percentage of conserved proteins compared to neighbouring taxa confirm that it does not belong to a known genus within Spirochaetaceae. We propose the name Candidatus Haliotispira prima gen. nov., sp. nov. based on its taxonomic placement and origin. We also tested for the presence of this species in different species of abalone and found that it is also present in white abalone (Haliotis sorenseni). In addition, we highlight the need for better classification of taxa within the class Spirochaetia.
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Affiliation(s)
| | - Catherine M Purcell
- NOAA Fisheries Southwest Fisheries Science Center, La Jolla, California, USA
| | - John R Hyde
- NOAA Fisheries Southwest Fisheries Science Center, La Jolla, California, USA
| | - Andrew J Severin
- Genome Informatics Facility, Iowa State University, Ames, Iowa, USA
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4
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Tannoo RM, Richert L, Koschut D, Tomishige N, Treffert SM, Kobayashi T, Mély Y, Orian-Rousseau V. Quantitative live imaging reveals a direct interaction between CD44v6 and MET in membrane domains upon activation with both MET ligands, HGF and internalin B. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184236. [PMID: 37793560 DOI: 10.1016/j.bbamem.2023.184236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 09/24/2023] [Accepted: 09/27/2023] [Indexed: 10/06/2023]
Abstract
Deregulation of the receptor tyrosine kinase MET/hepatocyte growth factor (HGF) pathway results in several pathological processes involved in tumor progression and metastasis. In a different context, MET can serve as an entry point for the bacterium Listeria monocytogenes, when activated by the internalin B (InlB) protein during infection of non-phagocytic cells. We have previously demonstrated that MET requires CD44v6 for its ligand-induced activation. However, the stoichiometry and the steps required for the formation of this complex, are still unknown. In this work, we studied the dynamics of the ligand-induced interaction of CD44v6 with MET at the plasma membrane. Using Förster resonance energy transfer-based fluorescence lifetime imaging microscopy in T-47D cells, we evidenced a direct interaction between MET and CD44v6 promoted by HGF and InlB in live cells. In the absence of MET, fluorescence correlation spectroscopy experiments further showed the dimerization of CD44v6 and the increase of its diffusion induced by HGF and InlB. In the presence of MET, stimulation of the cells by HGF or InlB significantly decreased the diffusion of CD44v6, in line with the formation of a ternary complex of MET with CD44v6 and HGF/InlB. Finally, similarly to HGF/InlB, disruption of liquid-ordered domains (Lo) by methyl-β-cyclodextrin increased CD44v6 mobility suggesting that these factors induce the exit of CD44v6 from the Lo domains. Our data led us to propose a model for MET activation, where CD44v6 dimerizes and diffuses rapidly out of Lo domains to form an oligomeric MET/ligand/CD44v6 complex that is instrumental for MET activation.
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Affiliation(s)
- Ryshtee Mary Tannoo
- Laboratory of Bioimaging and Pathologies (LBP), University of Strasbourg (UNISTRA), France; Institute of Biological and Chemical systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Germany
| | - Ludovic Richert
- Laboratory of Bioimaging and Pathologies (LBP), University of Strasbourg (UNISTRA), France.
| | - David Koschut
- Institute of Biological and Chemical systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Germany; Disease Intervention Technology Lab (DITL), Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology, and Research (A*STAR), Singapore
| | - Nario Tomishige
- Laboratory of Bioimaging and Pathologies (LBP), University of Strasbourg (UNISTRA), France
| | - Sven Máté Treffert
- Institute of Biological and Chemical systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Germany
| | - Toshihide Kobayashi
- Laboratory of Bioimaging and Pathologies (LBP), University of Strasbourg (UNISTRA), France
| | - Yves Mély
- Laboratory of Bioimaging and Pathologies (LBP), University of Strasbourg (UNISTRA), France.
| | - Véronique Orian-Rousseau
- Institute of Biological and Chemical systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Germany.
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5
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Margarita V, Bailey NP, Rappelli P, Diaz N, Dessì D, Fettweis JM, Hirt RP, Fiori PL. Two Different Species of Mycoplasma Endosymbionts Can Influence Trichomonas vaginalis Pathophysiology. mBio 2022; 13:e0091822. [PMID: 35608298 PMCID: PMC9239101 DOI: 10.1128/mbio.00918-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 04/28/2022] [Indexed: 12/12/2022] Open
Abstract
Trichomonas vaginalis can host the endosymbiont Mycoplasma hominis, an opportunistic pathogenic bacterium capable of modulating T. vaginalis pathobiology. Recently, a new noncultivable mycoplasma, "Candidatus Mycoplasma girerdii," has been shown to be closely associated with women affected by trichomoniasis, suggesting a biological association. Although several features of "Ca. M. girerdii" have been investigated through genomic analysis, the nature of the potential T. vaginalis-"Ca. M. girerdii" consortium and its impact on the biology and pathogenesis of both microorganisms have not yet been explored. Here, we investigate the association between "Ca. M. girerdii" and T. vaginalis isolated from patients affected by trichomoniasis, demonstrating their intracellular localization. By using an in vitro model system based on single- and double-Mycoplasma infection of Mycoplasma-free isogenic T. vaginalis, we investigated the ability of the protist to establish a relationship with the bacteria and impact T. vaginalis growth. Our data indicate likely competition between M. hominis and "Ca. M. girerdii" while infecting trichomonad cells. Comparative dual-transcriptomics data showed major shifts in parasite gene expression in response to the presence of Mycoplasma, including genes associated with energy metabolism and pathogenesis. Consistent with the transcriptomics data, both parasite-mediated hemolysis and binding to host epithelial cells were significantly upregulated in the presence of either Mycoplasma species. Taken together, these results support a model in which this microbial association could modulate the virulence of T. vaginalis. IMPORTANCE T. vaginalis and M. hominis form a unique case of endosymbiosis that modulates the parasite's pathobiology. Recently, a new nonculturable mycoplasma species ("Candidatus Mycoplasma girerdii") has been described as closely associated with the protozoon. Here, we report the characterization of this endosymbiotic relationship. Clinical isolates of the parasite demonstrate that mycoplasmas are common among trichomoniasis patients. The relationships are studied by devising an in vitro system of single and/or double infections in isogenic protozoan recipients. Comparative growth experiments and transcriptomics data demonstrate that the composition of different microbial consortia influences the growth of the parasite and significantly modulates its transcriptomic profile, including metabolic enzymes and virulence genes such as adhesins and pore-forming proteins. The data on modulation from RNA sequencing (RNA-Seq) correlated closely with those of the cytopathic effect and adhesion to human target cells. We propose the hypothesis that the presence and the quantitative ratios of endosymbionts may contribute to modulating protozoan virulence. Our data highlight the importance of considering pathogenic entities as microbial ecosystems, reinforcing the importance of the development of integrated diagnostic and therapeutic strategies.
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Affiliation(s)
| | - Nicholas P. Bailey
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Paola Rappelli
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
- Mediterranean Center for Disease Control (MCDC), Sassari, Italy
| | - Nicia Diaz
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Daniele Dessì
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
- Mediterranean Center for Disease Control (MCDC), Sassari, Italy
| | - Jennifer M. Fettweis
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, USA
- Department of Obstetrics and Gynecology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, USA
- Center for Microbiome Engineering and Data Analysis, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Robert P. Hirt
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Pier Luigi Fiori
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
- Mediterranean Center for Disease Control (MCDC), Sassari, Italy
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6
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Proteomic Characterization of the Oral Pathogen Filifactor alocis Reveals Key Inter-Protein Interactions of Its RTX Toxin: FtxA. Pathogens 2022; 11:pathogens11050590. [PMID: 35631111 PMCID: PMC9145396 DOI: 10.3390/pathogens11050590] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/11/2022] [Accepted: 05/15/2022] [Indexed: 11/16/2022] Open
Abstract
Filifactor alocis is a Gram-positive asaccharolytic, obligate anaerobic rod that has been isolated from a variety of oral infections including periodontitis, peri-implantitis, and odontogenic abscesses. As a newly emerging pathogen, its type strain has been investigated for pathogenic properties, yet little is known about its virulence variations among strains. We previously screened the whole genome of nine clinical oral isolates and a reference strain of F. alocis, and they expressed a novel RTX toxin, FtxA. In the present study, we aimed to use label-free quantification proteomics to characterize the full proteome of those ten F. alocis strains. A total of 872 proteins were quantified, and 97 among them were differentially expressed in FtxA-positive strains compared with the negative strains. In addition, 44 of these differentially expressed proteins formed 66 pairs of associations based on their predicted functions, which included clusters of proteins with DNA repair/mediated transformation and catalytic activity-related function, indicating different biosynthetic activities among strains. FtxA displayed specific interactions with another six intracellular proteins, forming a functional cluster that could discriminate between FtxA-producing and non-producing strains. Among them were FtxB and FtxD, predicted to be encoded by the same operon as FtxA. While revealing the broader qualitative and quantitative proteomic landscape of F. alocis, this study also sheds light on the deeper functional inter-relationships of FtxA, thus placing this RTX family member into context as a major virulence factor of this species.
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7
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Ostrowski MP, La Rosa SL, Kunath BJ, Robertson A, Pereira G, Hagen LH, Varghese NJ, Qiu L, Yao T, Flint G, Li J, McDonald SP, Buttner D, Pudlo NA, Schnizlein MK, Young VB, Brumer H, Schmidt TM, Terrapon N, Lombard V, Henrissat B, Hamaker B, Eloe-Fadrosh EA, Tripathi A, Pope PB, Martens EC. Mechanistic insights into consumption of the food additive xanthan gum by the human gut microbiota. Nat Microbiol 2022; 7:556-569. [PMID: 35365790 DOI: 10.1038/s41564-022-01093-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/24/2022] [Indexed: 12/13/2022]
Abstract
Processed foods often include food additives such as xanthan gum, a complex polysaccharide with unique rheological properties, that has established widespread use as a stabilizer and thickening agent. Xanthan gum's chemical structure is distinct from those of host and dietary polysaccharides that are more commonly expected to transit the gastrointestinal tract, and little is known about its direct interaction with the gut microbiota, which plays a central role in digestion of other dietary fibre polysaccharides. Here we show that the ability to digest xanthan gum is common in human gut microbiomes from industrialized countries and appears contingent on a single uncultured bacterium in the family Ruminococcaceae. Our data reveal that this primary degrader cleaves the xanthan gum backbone before processing the released oligosaccharides using additional enzymes. Some individuals harbour Bacteroides intestinalis that is incapable of consuming polymeric xanthan gum but grows on oligosaccharide products generated by the Ruminococcaceae. Feeding xanthan gum to germfree mice colonized with a human microbiota containing the uncultured Ruminococcaceae supports the idea that the additive xanthan gum can drive expansion of the primary degrader Ruminococcaceae, along with exogenously introduced B. intestinalis. Our work demonstrates the existence of a potential xanthan gum food chain involving at least two members of different phyla of gut bacteria and provides an initial framework for understanding how widespread consumption of a recently introduced food additive influences human microbiomes.
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Affiliation(s)
- Matthew P Ostrowski
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Sabina Leanti La Rosa
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.,Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway
| | - Benoit J Kunath
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Andrew Robertson
- Life Sciences Institute: Natural Products Discovery Core, University of Michigan, Ann Arbor, MI, USA
| | - Gabriel Pereira
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Live H Hagen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | | | - Ling Qiu
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Tianming Yao
- Department of Food Science and Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN, USA
| | - Gabrielle Flint
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - James Li
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sean P McDonald
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Duna Buttner
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Nicholas A Pudlo
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Matthew K Schnizlein
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Vincent B Young
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA.,Department of Internal Medicine, Infectious Diseases Division, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Thomas M Schmidt
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Nicolas Terrapon
- Centre National de la Recherche Scientifique, Aix-Marseille Univ, Marseille, France.,Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Marseille, France
| | - Vincent Lombard
- Centre National de la Recherche Scientifique, Aix-Marseille Univ, Marseille, France.,Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Marseille, France
| | - Bernard Henrissat
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Technical University of Denmark, DTU Bioengineering, Lyngby, Denmark
| | - Bruce Hamaker
- Department of Food Science and Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN, USA
| | | | - Ashootosh Tripathi
- Life Sciences Institute: Natural Products Discovery Core, University of Michigan, Ann Arbor, MI, USA
| | - Phillip B Pope
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway. .,Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway.
| | - Eric C Martens
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA.
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8
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Geerds C, Bleymüller WM, Meyer T, Widmann C, Niemann HH. A recurring packing contact in crystals of InlB pinpoints functional binding sites in the internalin domain and the B repeat. Acta Crystallogr D Struct Biol 2022; 78:310-320. [PMID: 35234145 PMCID: PMC8900821 DOI: 10.1107/s2059798322000432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 01/12/2022] [Indexed: 11/10/2022] Open
Abstract
InlB, a bacterial agonist of the human receptor tyrosine kinase MET, consists of an N-terminal internalin domain, a central B repeat and three C-terminal GW domains. In all previous structures of full-length InlB or an InlB construct lacking the GW domains (InlB392), there was no interpretable electron density for the B repeat. Here, three InlB392 crystal structures in which the B repeat is resolved are described. These are the first structures to reveal the relative orientation of the internalin domain and the B repeat. A wild-type structure and two structures of the T332E variant together contain five crystallographically independent molecules. Surprisingly, the threonine-to-glutamate substitution in the B repeat substantially improved the crystallization propensity and crystal quality of the T332E variant. The internalin domain and B repeat are quite rigid internally, but are flexibly linked to each other. The new structures show that inter-domain flexibility is the most likely cause of the missing electron density for the B repeat in previous InlB structures. A potential binding groove between B-repeat strand β2 and an adjacent loop forms an important crystal contact in all five crystallographically independent chains. This region may represent a hydrophobic `sticky patch' that supports protein-protein interactions. This assumption agrees with the previous finding that all known inactivating point mutations in the B repeat lie within strand β2. The groove formed by strand β2 and the adjacent loop may thus represent a functionally important protein-protein interaction site in the B repeat.
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Affiliation(s)
- Christina Geerds
- Department of Chemistry, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany
| | - Willem M. Bleymüller
- Department of Chemistry, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany
| | - Timo Meyer
- Department of Chemistry, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany
| | - Christiane Widmann
- Department of Chemistry, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany
| | - Hartmut H. Niemann
- Department of Chemistry, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany
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9
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Chalenko Y, Kolbasova O, Pivova E, Abdulkadieva M, Povolyaeva O, Kalinin E, Kolbasov D, Ermolaeva S. Listeria monocytogenes Invasion Into Sheep Kidney Epithelial Cells Depends on InlB, and Invasion Efficiency Is Modulated by Phylogenetically Defined InlB Isoforms. Front Microbiol 2022; 13:825076. [PMID: 35197955 PMCID: PMC8859113 DOI: 10.3389/fmicb.2022.825076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/05/2022] [Indexed: 11/13/2022] Open
Abstract
The facultative intracellular pathogen Listeria monocytogenes is of major veterinary importance in small ruminants. Nevertheless, details of L. monocytogenes interactions with cells of small ruminants are not fully established. To study the potential of L. monocytogenes to infect sheep cells, we used the finite sheep kidney cell line (shKEC), which was infected with the wild-type L. monocytogenes strain EGDe. The invasion efficiency was 0.015 ± 0.004%. The invasion factor InlB was critically important for invasion, and inlB gene deletion almost prevented L. monocytogenes invasion into shKEC cells. Comparison of the potential of phylogenetically defined InlB isoforms to restore the invasive phenotype of the EGDeΔinlB strain demonstrated that although all InlB isoforms restored invasion of the EGDeΔinlB strain into shKEC cells, the InlB isoforms typical of highly virulent ruminant strains of the clonal complexes CC1 and CC7 were more efficient than isoforms typical of CC2 and CC9 strains (which are less virulent toward ruminants) in supporting invasion. Listeria monocytogenes effectively multiplied with a doubling of time in about 90 min after they entered the sheep cells. Intracellular bacteria moved using the well-known actin polymerization mechanism. Cell-to-cell spreading was restricted to the infection of a few tens of neighboring cells for 7 days. Overall, the obtained results demonstrated that (i) InlB is required for invasion into sheep cells, (ii) InlB isoforms might be important for hypervirulence of certain clonal groups toward ruminants, and (iii) L. monocytogenes effectively multiplies in ovine cells once entered.
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Affiliation(s)
- Yaroslava Chalenko
- Laboratory of Ecology of Pathogenic Bacteria, Gamaleya Research Center of Epidemiology and Microbiology, Moscow, Russia
- Yaroslava Chalenko,
| | - Olga Kolbasova
- Federal Research Center for Virology and Microbiology (FRCVM), Volginsky, Russia
| | - Elena Pivova
- Federal Research Center for Virology and Microbiology (FRCVM), Volginsky, Russia
| | - Mariam Abdulkadieva
- Department of Dusty Plasma, Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow, Russia
| | - Olga Povolyaeva
- Federal Research Center for Virology and Microbiology (FRCVM), Volginsky, Russia
| | - Egor Kalinin
- Laboratory of Ecology of Pathogenic Bacteria, Gamaleya Research Center of Epidemiology and Microbiology, Moscow, Russia
| | - Denis Kolbasov
- Federal Research Center for Virology and Microbiology (FRCVM), Volginsky, Russia
| | - Svetlana Ermolaeva
- Laboratory of Ecology of Pathogenic Bacteria, Gamaleya Research Center of Epidemiology and Microbiology, Moscow, Russia
- Federal Research Center for Virology and Microbiology (FRCVM), Nizhny Novgorod Research Veterinary Institute Branch, Nizhny Novgorod, Russia
- *Correspondence: Svetlana Ermolaeva,
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10
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Chen Y, Simonetti T, Peter K, Jin Q, Brown E, LaBorde LF, Macarisin D. Genetic Diversity of Listeria monocytogenes Isolated From Three Commercial Tree Fruit Packinghouses and Evidence of Persistent and Transient Contamination. Front Microbiol 2022; 12:756688. [PMID: 35082763 PMCID: PMC8784831 DOI: 10.3389/fmicb.2021.756688] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/13/2021] [Indexed: 12/20/2022] Open
Abstract
Whole genome analysis was performed on 501 isolates obtained from a previous survey which recovered 139 positive environmental sponge samples (i.e., up to 4 isolates per sample) from a total of 719 samples collected at 40 standardized sites in 3 commercial apple packinghouse facilities (i.e., P1, P2, and P3) over 3 successive seasons in a single production year. After excluding duplicated isolates, the data from 156 isolates revealed the clonal diversity of L. monocytogenes and allowed the detection of transient contamination, persistent contamination, and cross-area transmission events. Facility P2 with the poorest sanitary conditions had the least diversity (Shannon's index of 0.38). P2 contained a Clonal Complex (CC) 554, serogroup IVb-v1 strain that persisted throughout the year and spread across the entire facility, a singleton Sequence Type (ST) 1003, lineage III strain that persisted through two seasons and spread across two areas of the facility, and 3 other clones from transient contaminations. P1 and P3, facilities with better sanitary conditions, had much higher diversity (i.e., 15 clones with a Shannon's index of 2.49 and 10 clones with a Shannon's index of 2.10, respectively) that were the result of transient contamination. Facilities P1 and P3 had the highest incidence (43.1%) of lineage III isolates, followed by lineage I (31.3%) and lineage II (25.5%) isolates. Only 1 isolate in the three facilities contained a premature stop codon in virulence gene inlA. Fourteen samples yielded 2-3 clones per sample, demonstrating the importance of choosing appropriate methodologies and selecting a sufficient number of isolates per sample for studying L. monocytogenes diversity. Only 1 isolate, belonging to CC5 and from facility P3, contained a known plasmid, and this was also the only isolate containing benzalkonium chloride tolerance genes. The persistent CC554 strain did not exhibit stronger sanitizer resistance than other isolates and did not contain any confirmed molecular determinants of L. monocytogenes stress resistance that were differentially present in other isolates, such as genes involved in sanitizer tolerance, heavy metal resistance, biofilm-forming, stress survival islet 1 (SSI-1), stress survival islet 2 (SSI-2) or Listeria genomic island (LGI2).
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Affiliation(s)
- Yi Chen
- Center for Food Safety and Applied Nutrition, Food and Drug Administration (FDA), College Park, MD, United States
| | - Tobin Simonetti
- Department of Food Science, Pennsylvania State University, University Park, PA, United States
| | - Kari Peter
- Fruit Research and Extension Center, Pennsylvania State University, University Park, PA, United States
| | - Qing Jin
- Center for Food Safety and Applied Nutrition, Food and Drug Administration (FDA), College Park, MD, United States
| | - Eric Brown
- Center for Food Safety and Applied Nutrition, Food and Drug Administration (FDA), College Park, MD, United States
| | - Luke F LaBorde
- Department of Food Science, Pennsylvania State University, University Park, PA, United States
| | - Dumitru Macarisin
- Center for Food Safety and Applied Nutrition, Food and Drug Administration (FDA), College Park, MD, United States
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11
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Thomas CM, Taib N, Gribaldo S, Borrel G. Comparative genomic analysis of Methanimicrococcus blatticola provides insights into host adaptation in archaea and the evolution of methanogenesis. ISME COMMUNICATIONS 2021; 1:47. [PMID: 37938279 PMCID: PMC9723798 DOI: 10.1038/s43705-021-00050-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 07/08/2021] [Accepted: 08/26/2021] [Indexed: 05/15/2023]
Abstract
Other than the Methanobacteriales and Methanomassiliicoccales, the characteristics of archaea that inhabit the animal microbiome are largely unknown. Methanimicrococcus blatticola, a member of the Methanosarcinales, currently reunites two unique features within this order: it is a colonizer of the animal digestive tract and can only reduce methyl compounds with H2 for methanogenesis, a increasingly recognized metabolism in the archaea and whose origin remains debated. To understand the origin of these characteristics, we have carried out a large-scale comparative genomic analysis. We infer the loss of more than a thousand genes in M. blatticola, by far the largest genome reduction across all Methanosarcinales. These include numerous elements for sensing the environment and adapting to more stable gut conditions, as well as a significant remodeling of the cell surface components likely involved in host and gut microbiota interactions. Several of these modifications parallel those previously observed in phylogenetically distant archaea and bacteria from the animal microbiome, suggesting large-scale convergent mechanisms of adaptation to the gut. Strikingly, M. blatticola has lost almost all genes coding for the H4MPT methyl branch of the Wood-Ljungdahl pathway (to the exception of mer), a phenomenon never reported before in any member of Class I or Class II methanogens. The loss of this pathway illustrates one of the evolutionary processes that may have led to the emergence of methyl-reducing hydrogenotrophic methanogens, possibly linked to the colonization of organic-rich environments (including the animal gut) where both methyl compounds and hydrogen are abundant.
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Affiliation(s)
- Courtney M Thomas
- Department of Microbiology, UMR 2001, Unit Evolutionary Biology of the Microbial Cell, Institut Pasteur, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Najwa Taib
- Department of Microbiology, UMR 2001, Unit Evolutionary Biology of the Microbial Cell, Institut Pasteur, Paris, France
| | - Simonetta Gribaldo
- Department of Microbiology, UMR 2001, Unit Evolutionary Biology of the Microbial Cell, Institut Pasteur, Paris, France
| | - Guillaume Borrel
- Department of Microbiology, UMR 2001, Unit Evolutionary Biology of the Microbial Cell, Institut Pasteur, Paris, France.
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12
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Kalinin EV, Chalenko YM, Sysolyatina EV, Midiber KY, Gusarov AM, Kechko OI, Kulikova AA, Mikhaleva LM, Mukhachev AY, Stanishevskyi YM, Mitkevich VA, Sobyanin KA, Ermolaeva SA. Bacterial hepatocyte growth factor receptor agonist stimulates hepatocyte proliferation and accelerates liver regeneration in a partial hepatectomy rat model. Drug Dev Res 2021; 82:123-132. [PMID: 32830369 DOI: 10.1002/ddr.21737] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 08/06/2020] [Accepted: 08/07/2020] [Indexed: 12/20/2022]
Abstract
Hepatocyte growth factor (HGF) is central to liver regeneration. The Internalin B (InlB) protein is a virulence factor produced by the pathogenic bacterium Listeria monocytogenes. InlB is known to mimic HGF activity by interacting with the HGF receptor (HGFR) and activating HGFR-controlled signaling pathways. We expressed and purified the HGFR-binding InlB domain, InlB321/15, cloned from the fully virulent clinical L. monocytogenes strain. HGFR and Erk1/2 phosphorylation was determined using Western blotting. The capacity of InlB321/15 to bind HGFR was measured using microscale thermophoresis. Liver regeneration was studied in a model of 70% partial hepatectomy (70%PHx) in male Wistar rats. The nuclear grade parameters were quantified using manual (percentage of binuclear hepatocytes), automated (nuclear diameters), or combined (Ki67 proliferation index) scoring methods. Purified InlB321/15 stimulated HGFR and Erk1/2 phosphorylation and accelerated the proliferation of HepG2 cells. InlB321/15 bound HGFR with Kd = 7.4 ± 1.3 nM. InlB321/15 injected intravenously on the second, fourth, and sixth days after surgery recovered the liver mass and improved the nuclear grade parameters. Seven days post 70% PHx, the liver weight indexes were 2.9 and 2.0%, the hepatocyte proliferation indexes were 19.8 and 0.6%, and the percentages of binucleated hepatocytes were 6.7 and 4.0%, in the InlB321/15-treated and control animals, respectively. Obtained data demonstrated that InlB321/15 improved hepatocyte proliferation and stimulated liver regeneration in animals with 70% hepatectomy.
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Affiliation(s)
- Egor V Kalinin
- Gamaleya Research Center of Epidemiology and Microbiology, Moscow, Russia
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia
| | - Yaroslava M Chalenko
- Gamaleya Research Center of Epidemiology and Microbiology, Moscow, Russia
- Federal Research Center for Virology and Microbiology (FRCVM), Russian Academy of Sciences, Moscow, Russia
| | | | | | - Alexey M Gusarov
- Gamaleya Research Center of Epidemiology and Microbiology, Moscow, Russia
| | - Olga I Kechko
- Engelhardt Institute of Molecular Biology, Moscow, Russia
| | | | | | | | | | | | | | - Svetlana A Ermolaeva
- Gamaleya Research Center of Epidemiology and Microbiology, Moscow, Russia
- Federal Research Center for Virology and Microbiology (FRCVM), Russian Academy of Sciences, Moscow, Russia
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13
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Harter E, Lassnig C, Wagner EM, Zaiser A, Wagner M, Rychli K. The Novel Internalins InlP1 and InlP4 and the Internalin-Like Protein InlP3 Enhance the Pathogenicity of Listeria monocytogenes. Front Microbiol 2019; 10:1644. [PMID: 31396177 PMCID: PMC6664051 DOI: 10.3389/fmicb.2019.01644] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/03/2019] [Indexed: 01/08/2023] Open
Abstract
The pathogenicity of the human foodborne pathogen Listeria monocytogenes relies on virulence factors such as internalins. In 2009/2010 two L. monocytogenes strains were responsible for a serious listeriosis outbreak in Austria, Germany, and the Czech Republic. One of these clones, QOC1, which caused 14 cases including five fatalities, encodes the novel internalins inlP1, inlPq and inlP4, and the novel internalin-like protein inlP3 in the genomic region of hypervariable genetic hotspot 9 in addition to the standard set of virulence genes. The in silico prevalence study revealed that these genes rarely occur in L. monocytogenes, mainly in minor clonal complexes. To obtain first insights of the role of these genes in the pathogenicity of L. monocytogenes, we studied the gene expression under conditions mimicking the ingestion in the host. Expression of inlP1, inlP3, inlPq and inlP4 was increased under gastric stress and in intracellular bacteria grown in intestinal epithelial cells. Furthermore, colonization of the liver and the spleen was slightly, but significantly reduced 72 h post infection in an oral mouse infection model when inlP1 or inlP4 was deleted. Moreover, the impact of InlP1 and InlP3 in virulence was shown in vitro in human intestinal epithelial cells. In this study we conclusively demonstrate a potential contribution of uncommon novel internalins and an internalin-like protein to the pathogenicity of L. monocytogenes.
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Affiliation(s)
- Eva Harter
- Department for Farm Animals and Public Health in Veterinary Medicine, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Caroline Lassnig
- Department of Biomedical Sciences, Institute of Animal Breeding and Genetics and Biomodels Austria, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Eva Maria Wagner
- Department for Farm Animals and Public Health in Veterinary Medicine, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
- Austrian Competence Centre for Feed and Food Quality, Safety and Innovation – FFoQSI GmbH, Tulln, Austria
| | - Andreas Zaiser
- Department for Farm Animals and Public Health in Veterinary Medicine, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Martin Wagner
- Department for Farm Animals and Public Health in Veterinary Medicine, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
- Austrian Competence Centre for Feed and Food Quality, Safety and Innovation – FFoQSI GmbH, Tulln, Austria
| | - Kathrin Rychli
- Department for Farm Animals and Public Health in Veterinary Medicine, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
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14
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Leth ML, Ejby M, Workman C, Ewald DA, Pedersen SS, Sternberg C, Bahl MI, Licht TR, Aachmann FL, Westereng B, Abou Hachem M. Differential bacterial capture and transport preferences facilitate co-growth on dietary xylan in the human gut. Nat Microbiol 2018; 3:570-580. [PMID: 29610517 DOI: 10.1038/s41564-018-0132-8] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 02/19/2018] [Indexed: 12/11/2022]
Abstract
Metabolism of dietary glycans is pivotal in shaping the human gut microbiota. However, the mechanisms that promote competition for glycans among gut commensals remain unclear. Roseburia intestinalis, an abundant butyrate-producing Firmicute, is a key degrader of the major dietary fibre xylan. Despite the association of this taxon to a healthy microbiota, insight is lacking into its glycan utilization machinery. Here, we investigate the apparatus that confers R. intestinalis growth on different xylans. R. intestinalis displays a large cell-attached modular xylanase that promotes multivalent and dynamic association to xylan via four xylan-binding modules. This xylanase operates in concert with an ATP-binding cassette transporter to mediate breakdown and selective internalization of xylan fragments. The transport protein of R. intestinalis prefers oligomers of 4-5 xylosyl units, whereas the counterpart from a model xylan-degrading Bacteroides commensal targets larger ligands. Although R. intestinalis and the Bacteroides competitor co-grew in a mixed culture on xylan, R. intestinalis dominated on the preferred transport substrate xylotetraose. These findings highlight the differentiation of capture and transport preferences as a possible strategy to facilitate co-growth on abundant dietary fibres and may offer a unique route to manipulate the microbiota based on glycan transport preferences in therapeutic interventions to boost distinct taxa.
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Affiliation(s)
- Maria Louise Leth
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Morten Ejby
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Christopher Workman
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - David Adrian Ewald
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Signe Schultz Pedersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Claus Sternberg
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Martin Iain Bahl
- National Food Institute, Technical University of Denmark, Lyngby, Denmark
| | - Tine Rask Licht
- National Food Institute, Technical University of Denmark, Lyngby, Denmark
| | - Finn Lillelund Aachmann
- NOBIPOL, Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Bjørge Westereng
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Maher Abou Hachem
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark.
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15
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Moreno-Hagelsieb G, Vitug B, Medrano-Soto A, Saier MH. The Membrane Attack Complex/Perforin Superfamily. J Mol Microbiol Biotechnol 2017; 27:252-267. [PMID: 29145176 DOI: 10.1159/000481286] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 09/05/2017] [Indexed: 12/30/2022] Open
Abstract
The membrane attack complex/perforin (MACPF) superfamily consists of a diverse group of proteins involved in bacterial pathogenesis and sporulation as well as eukaryotic immunity, embryonic development, neural migration and fruiting body formation. The present work shows that the evolutionary relationships between the members of the superfamily, previously suggested by comparison of their tertiary structures, can also be supported by analyses of their primary structures. The superfamily includes the MACPF family (TC 1.C.39), the cholesterol-dependent cytolysin (CDC) family (TC 1.C.12.1 and 1.C.12.2) and the pleurotolysin pore-forming (pleurotolysin B) family (TC 1.C.97.1), as revealed by expansion of each family by comparison against a large protein database, and by the comparisons of their hidden Markov models. Clustering analyses demonstrated grouping of the CDC homologues separately from the 12 MACPF subfamilies, which also grouped separately from the pleurotolysin B family. Members of the MACPF superfamily revealed a remarkably diverse range of proteins spanning eukaryotic, bacterial, and archaeal taxonomic domains, with notable variations in protein domain architectures. Our strategy should also be helpful in putting together other highly divergent protein families.
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16
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Waller AS. Science-in-brief: Streptococcus zooepidemicus: a versatile opportunistic pathogen that hedges its bets in horses. Equine Vet J 2017; 49:146-148. [PMID: 28177154 DOI: 10.1111/evj.12658] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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Genomics and metagenomics of trimethylamine-utilizing Archaea in the human gut microbiome. ISME JOURNAL 2017; 11:2059-2074. [PMID: 28585938 DOI: 10.1038/ismej.2017.72] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 04/04/2017] [Accepted: 04/06/2017] [Indexed: 02/06/2023]
Abstract
The biological significance of Archaea in the human gut microbiota is largely unclear. We recently reported genomic and biochemical analyses of the Methanomassiliicoccales, a novel order of methanogenic Archaea dwelling in soil and the animal digestive tract. We now show that these Methanomassiliicoccales are present in published microbiome data sets from eight countries. They are represented by five Operational Taxonomic Units present in at least four cohorts and phylogenetically distributed into two clades. Genes for utilizing trimethylamine (TMA), a bacterial precursor to an atherosclerogenic human metabolite, were present in four of the six novel Methanomassiliicoccales genomes assembled from ELDERMET metagenomes. In addition to increased microbiota TMA production capacity in long-term residential care subjects, abundance of TMA-utilizing Methanomassiliicoccales correlated positively with bacterial gene count for TMA production and negatively with fecal TMA concentrations. The two large Methanomassiliicoccales clades have opposite correlations with host health status in the ELDERMET cohort and putative distinct genomic signatures for gut adaptation.
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18
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Bleymüller WM, Lämmermann N, Ebbes M, Maynard D, Geerds C, Niemann HH. MET-activating Residues in the B-repeat of the Listeria monocytogenes Invasion Protein InlB. J Biol Chem 2016; 291:25567-25577. [PMID: 27789707 DOI: 10.1074/jbc.m116.746685] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 10/26/2016] [Indexed: 12/20/2022] Open
Abstract
The facultative intracellular pathogen Listeria monocytogenes causes listeriosis, a rare but life-threatening disease. Host cell entry begins with activation of the human receptor tyrosine kinase MET through the bacterial invasion protein InlB, which contains an internalin domain, a B-repeat, and three GW domains. The internalin domain is known to bind MET, but no interaction partner is known for the B-repeat. Adding the B-repeat to the internalin domain potentiates MET activation and is required to stimulate Madin-Darby canine kidney (MDCK) cell scatter. Therefore, it has been hypothesized that the B-repeat may bind a co-receptor on host cells. To test this hypothesis, we mutated residues that might be important for binding an interaction partner. We identified two adjacent residues in strand β2 of the β-grasp fold whose mutation abrogated induction of MDCK cell scatter. Biophysical analysis indicated that these mutations do not alter protein structure. We then tested these mutants in human HT-29 cells that, in contrast to the MDCK cells, were responsive to the internalin domain alone. These assays revealed a dominant negative effect, reducing the activity of a construct of the internalin domain and mutated B-repeat below that of the individual internalin domain. Phosphorylation assays of MET and its downstream targets AKT and ERK confirmed the dominant negative effect. Attempts to identify a host cell receptor for the B-repeat were not successful. We conclude that there is limited support for a co-receptor hypothesis and instead suggest that the B-repeat contributes to MET activation through low affinity homodimerization.
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Affiliation(s)
- Willem M Bleymüller
- From the Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
| | - Nina Lämmermann
- From the Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
| | - Maria Ebbes
- From the Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
| | - Daniel Maynard
- From the Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
| | - Christina Geerds
- From the Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
| | - Hartmut H Niemann
- From the Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
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19
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Koschut D, Richert L, Pace G, Niemann HH, Mély Y, Orian-Rousseau V. Live cell imaging shows hepatocyte growth factor-induced Met dimerization. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1863:1552-8. [PMID: 27094128 DOI: 10.1016/j.bbamcr.2016.04.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 04/01/2016] [Accepted: 04/15/2016] [Indexed: 12/24/2022]
Abstract
The canonical model of receptor tyrosine kinase (RTK) activation assumes that ligand-induced dimerization of inactive receptor monomers is a prerequisite for autophosphorylation. For several RTK families, recent results of fluorescence microscopy provided evidence for preformed receptor dimers that may or may not require ligand binding for kinase activity. Here we report, for the first time, the application of advanced quantitative fluorescence microscopy techniques to study changes in the oligomerization state of the RTK Met in response to stimulation by its endogenous ligand hepatocyte growth factor (HGF). We used inducible C-terminal fusions between Met and enhanced green fluorescent protein (EGFP) or red fluorescent protein (RFP) in combination with fluorescence resonance energy transfer (FRET)-based fluorescence-lifetime imaging microscopy (FLIM) and fluorescence correlation spectroscopy (FCS). A small fraction of HGF-independent Met dimers appeared to be present in cells even at low receptor density. At high receptor density, both the fraction of Met dimers and the level of Met autophosphorylation increased in the absence of HGF. Stimulation with HGF at low receptor density significantly increased the fraction of Met dimers on live cells. We found no indications of Met oligomers larger than dimers. Our findings thus confirm a model of Met activation through HGF-induced dimerization and at the same time they support previous reports of Met dimers in unstimulated cells. The tools established in this work will be useful to further characterize the mechanism of Met activation and to define the contribution of co-receptors.
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Affiliation(s)
- David Koschut
- Karlsruhe Institute of Technology (KIT), Institute of Toxicology and Genetics (ITG), Postfach 3640, 76021 Karlsruhe, Germany
| | - Ludovic Richert
- UMR 7213 CNRS, Laboratoire de Biophotonique et Pharmacologie, Faculté de Pharmacie 74 route du Rhin, 67401 Illkirch, France
| | - Giuseppina Pace
- Karlsruhe Institute of Technology (KIT), Institute of Toxicology and Genetics (ITG), Postfach 3640, 76021 Karlsruhe, Germany
| | - Hartmut H Niemann
- Department of Chemistry, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany
| | - Yves Mély
- UMR 7213 CNRS, Laboratoire de Biophotonique et Pharmacologie, Faculté de Pharmacie 74 route du Rhin, 67401 Illkirch, France
| | - Véronique Orian-Rousseau
- Karlsruhe Institute of Technology (KIT), Institute of Toxicology and Genetics (ITG), Postfach 3640, 76021 Karlsruhe, Germany.
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20
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Steward KF, Harrison T, Robinson C, Slater J, Maskell DJ, Harris SR, Holden MTG, Waller AS. PinR mediates the generation of reversible population diversity in Streptococcus zooepidemicus. MICROBIOLOGY-SGM 2015; 161:1105-1112. [PMID: 25701732 DOI: 10.1099/mic.0.000057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 02/10/2015] [Indexed: 11/18/2022]
Abstract
Opportunistic pathogens must adapt to and survive in a wide range of complex ecosystems. Streptococcus zooepidemicus is an opportunistic pathogen of horses and many other animals, including humans. The assembly of different surface architecture phenotypes from one genotype is likely to be crucial to the successful exploitation of such an opportunistic lifestyle. Construction of a series of mutants revealed that a serine recombinase, PinR, inverts 114 bp of the promoter of SZO_08560, which is bordered by GTAGACTTTA and TAAAGTCTAC inverted repeats. Inversion acts as a switch, controlling the transcription of this sortase-processed protein, which may enhance the attachment of S. zooepidemicus to equine trachea. The genome of a recently sequenced strain of S. zooepidemicus, 2329 (Sz2329), was found to contain a disruptive internal inversion of 7 kb of the FimIV pilus locus, which is bordered by TAGAAA and TTTCTA inverted repeats. This strain lacks pinR and this inversion may have become irreversible following the loss of this recombinase. Active inversion of FimIV was detected in three strains of S. zooepidemicus, 1770 (Sz1770), B260863 (SzB260863) and H050840501 (SzH050840501), all of which encoded pinR. A deletion mutant of Sz1770 that lacked pinR was no longer capable of inverting its internal region of FimIV. The data highlight redundancy in the PinR sequence recognition motif around a short TAGA consensus and suggest that PinR can reversibly influence the wider surface architecture of S. zooepidemicus, providing this organism with a bet-hedging solution to survival in fluctuating environments.
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Affiliation(s)
| | | | - Carl Robinson
- Animal Health Trust, Kentford, Newmarket CB8 7UU, UK
| | - Josh Slater
- Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK
| | - Duncan J Maskell
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, UK
| | - Simon R Harris
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK
| | - Matthew T G Holden
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK
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21
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Etzold S, Juge N. Structural insights into bacterial recognition of intestinal mucins. Curr Opin Struct Biol 2014; 28:23-31. [PMID: 25106027 DOI: 10.1016/j.sbi.2014.07.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/09/2014] [Accepted: 07/16/2014] [Indexed: 01/06/2023]
Abstract
The mucosal layer covering our gut epithelium represents the first line of host defenses against the luminal content, while enabling contacts between the resident microbiota and the host. Mucus is mainly composed of mucins, large glycoproteins containing a protein core and a high number of O-linked oligosaccharides. Mucin glycans act as binding sites or carbon sources for the intestinal microbes, thereby functioning as a host-specific determinant affecting the microbiota composition and human health. Reflecting the structural diversity of mucin glycans and their prime location, commensal and pathogenic microbes have evolved a range of adhesins allowing their interaction with the host. However, despite the recognised importance of mucin glycans in modulating intestinal homeostasis, information on carbohydrate-binding proteins from gut bacteria is disparate. This review is focussed on recent structural insights into host-microbe interactions mediated by mucins.
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Affiliation(s)
- Sabrina Etzold
- Division of Neonatology and Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, School of Medicine, University of California San Diego, 9500 Gilman Drive, San Diego, CA 92093-0715, USA
| | - Nathalie Juge
- The Gut Health and Food Safety Institute Strategic Programme, Institute of Food Research, Norwich NR4 7UA, United Kingdom.
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22
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Crystal structure of an engineered YopM-InlB hybrid protein. BMC STRUCTURAL BIOLOGY 2014; 14:12. [PMID: 24669959 PMCID: PMC3986869 DOI: 10.1186/1472-6807-14-12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 03/21/2014] [Indexed: 11/10/2022]
Abstract
Background The multi-domain protein InlB (internalin B) from Listeria monocytogenes is an agonist of the human receptor tyrosine kinase MET. Only the internalin domain directly interacts with MET. The internalin domain consists of seven central leucine-rich repeats (LRRs) flanked by an N-terminal helical cap domain and a C-terminal immunoglobulin-like structure. A potential function of the N-terminal cap in receptor binding could so far not be demonstrated by deleting the cap, since the cap is also implicated in nucleating folding of the LRR domain. Results We generated an InlB variant (YopM-InlB) in which the InlB cap domain was replaced by the unrelated N-terminal capping structure of the LRR protein YopM from Yersinia enterocolitica. The crystal structure of the engineered protein shows that it folds properly. Because the first LRR is structurally closely linked to the cap domain, we exchanged LRR1 along with the cap domain. This resulted in unexpected structural changes extending to LRR2 and LRR3, which are deeply involved in MET binding. As a consequence, the binding of YopM-InlB to MET was substantially weaker than that of wild type InlB. The engineered protein was about one order of magnitude less active in colony scatter assays than wild type InlB. Conclusions We obtained a well-behaved InlB variant with an altered N-terminal capping structure through protein design. The reduced affinity for MET precludes a straightforward interpretation of the results from cell-based assays. Still, the engineered hybrid protein induced cell scatter, suggesting that the cap is required for folding and stability of InlB but is not essential for interactions that assemble the signalling-active receptor complex. The cap swap approach described here is clearly applicable to other L. monocytogenes internalins and other LRR proteins such as YopM and may yield useful structure/function correlates within this protein family.
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Etzold S, Kober OI, Mackenzie DA, Tailford LE, Gunning AP, Walshaw J, Hemmings AM, Juge N. Structural basis for adaptation of lactobacilli to gastrointestinal mucus. Environ Microbiol 2014; 16:888-903. [PMID: 24373178 DOI: 10.1111/1462-2920.12377] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 12/17/2013] [Accepted: 12/17/2013] [Indexed: 12/01/2022]
Abstract
The mucus layer covering the gastrointestinal (GI) epithelium is critical in selecting and maintaining homeostatic interactions with our gut bacteria. However, the underpinning mechanisms of these interactions are not understood. Here, we provide structural and functional insights into the canonical mucus-binding protein (MUB), a multi-repeat cell-surface adhesin found in Lactobacillus inhabitants of the GI tract. X-ray crystallography together with small-angle X-ray scattering demonstrated a 'beads on a string' arrangement of repeats, generating 174 nm long protein fibrils, as shown by atomic force microscopy. Each repeat consists of tandemly arranged Ig- and mucin-binding protein (MucBP) modules. The binding of full-length MUB was confined to mucus via multiple interactions involving terminal sialylated mucin glycans. While individual MUB domains showed structural similarity to fimbrial proteins from Gram-positive pathogens, the particular organization of MUB provides a structural explanation for the mechanisms in which lactobacilli have adapted to their host niche by maximizing interactions with the mucus receptors, potentiating the retention of bacteria within the mucus layer. Together, this study reveals functional and structural features which may affect tropism of microbes across mucus and along the GI tract, providing unique insights into the mechanisms adopted by commensals and probiotics to adapt to the mucosal environment.
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Affiliation(s)
- Sabrina Etzold
- Institute of Food Research, Gut Health and Food Safety Institute Strategic Programme, Norwich Research Park, Norwich, NR4 7UA, UK
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Dietz MS, Fricke F, Krüger CL, Niemann HH, Heilemann M. Receptor-Ligand Interactions: Binding Affinities Studied by Single-Molecule and Super-Resolution Microscopy on Intact Cells. Chemphyschem 2013; 15:671-6. [DOI: 10.1002/cphc.201300755] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Wound healing potential of a dimeric InlB variant analyzed by in vitro experiments on re-epithelialization of human skin models. Eur J Pharm Biopharm 2013; 86:277-83. [PMID: 24140590 DOI: 10.1016/j.ejpb.2013.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 10/04/2013] [Accepted: 10/07/2013] [Indexed: 12/11/2022]
Abstract
A constitutively dimeric truncated variant of internalin B (InlB321-CD), acting as stimulator of the receptor tyrosine kinase MET, was tested for dermal wound-healing potential. Due to a lack of the endogenous MET agonist HGF/SF in chronic wounds, HGF/SF substitution by an InlB321-CD-loaded hydrogel might be beneficial in chronic wound therapy. In this study, InlB321-CD in solution and incorporated in a hydrogel was tested for mitogenic effects on immortalized human dermal keratinocytes (HaCaT) with an MTT assay. Cell migration was investigated with a scratch assay on primary keratinocytes (PHK) and on HaCaT. For the latter, scratching needed to be mitomycin C-controlled. InlB321-CD effects on a model of human skin were analyzed histologically with respect to viability. InlB321-CD led to dose-dependent proliferative effects on HaCaT cells whereas the equimolar dose of monomeric InlB321 did not. Upon hydrogel incorporation of InlB321-CD its mitogenic activity for HaCaT cells was maintained thus confirming the hydrogel as a promising drug delivery system. Motogenic effects were shown on both HaCaT and PHK cells. InlB321-CD neither possesses cytotoxic effects on the viability of a human skin model nor alters its organotypic cell morphology.
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Neves D, Job V, Dortet L, Cossart P, Dessen A. Structure of internalin InlK from the human pathogen Listeria monocytogenes. J Mol Biol 2013; 425:4520-9. [PMID: 23958637 DOI: 10.1016/j.jmb.2013.08.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/08/2013] [Accepted: 08/11/2013] [Indexed: 01/22/2023]
Abstract
Listeria monocytogenes is a human pathogen that employs a wide variety of virulence factors in order to adhere to, invade, and replicate within target cells. Internalins play key roles in processes ranging from adhesion to receptor recognition and are thus essential for infection. Recently, InlK, a surface-associated internalin, was shown to be involved in Listeria's ability to escape from autophagy by recruitment of the major vault protein (MVP) to the bacterial surface. Here, we report the structure of InlK, which harbors four domains arranged in the shape of a "bent arm". The structure supports a role for the "elbow" of InlK in partner recognition, as well as of two Ig-like pedestals intercalated by hinge regions in the projection of InlK away from the surface of the bacterium. The unusual fold and flexibility of InlK could be essential for MVP binding and concealment from recognition by molecules involved in the autophagic process.
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Affiliation(s)
- David Neves
- Brazilian National Laboratory for Biosciences (LNBio), CNPEM, Campinas, São Paulo, Brazil
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Dietz MS, Haße D, Ferraris DM, Göhler A, Niemann HH, Heilemann M. Single-molecule photobleaching reveals increased MET receptor dimerization upon ligand binding in intact cells. BMC BIOPHYSICS 2013; 6:6. [PMID: 23731667 PMCID: PMC3674922 DOI: 10.1186/2046-1682-6-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/23/2013] [Indexed: 12/14/2022]
Abstract
Background The human receptor tyrosine kinase MET and its ligand hepatocyte growth factor/scatter factor are essential during embryonic development and play an important role during cancer metastasis and tissue regeneration. In addition, it was found that MET is also relevant for infectious diseases and is the target of different bacteria, amongst them Listeria monocytogenes that induces bacterial uptake through the surface protein internalin B. Binding of ligand to the MET receptor is proposed to lead to receptor dimerization. However, it is also discussed whether preformed MET dimers exist on the cell membrane. Results To address these issues we used single-molecule fluorescence microscopy techniques. Our photobleaching experiments show that MET exists in dimers on the membrane of cells in the absence of ligand and that the proportion of MET dimers increases significantly upon ligand binding. Conclusions Our results indicate that partially preformed MET dimers may play a role in ligand binding or MET signaling. The addition of the bacterial ligand internalin B leads to an increase of MET dimers which is in agreement with the model of ligand-induced dimerization of receptor tyrosine kinases.
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Affiliation(s)
- Marina S Dietz
- Institute of Physical and Theoretical Chemistry, Johann Wolfgang Goethe-University, Max-von-Laue-Str, 7, 60438 Frankfurt, Germany.
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Kuenne C, Billion A, Mraheil MA, Strittmatter A, Daniel R, Goesmann A, Barbuddhe S, Hain T, Chakraborty T. Reassessment of the Listeria monocytogenes pan-genome reveals dynamic integration hotspots and mobile genetic elements as major components of the accessory genome. BMC Genomics 2013; 14:47. [PMID: 23339658 PMCID: PMC3556495 DOI: 10.1186/1471-2164-14-47] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 12/15/2012] [Indexed: 12/14/2022] Open
Abstract
Background Listeria monocytogenes is an important food-borne pathogen and model organism for host-pathogen interaction, thus representing an invaluable target considering research on the forces governing the evolution of such microbes. The diversity of this species has not been exhaustively explored yet, as previous efforts have focused on analyses of serotypes primarily implicated in human listeriosis. We conducted complete genome sequencing of 11 strains employing 454 GS FLX technology, thereby achieving full coverage of all serotypes including the first complete strains of serotypes 1/2b, 3c, 3b, 4c, 4d, and 4e. These were comparatively analyzed in conjunction with publicly available data and assessed for pathogenicity in the Galleria mellonella insect model. Results The species pan-genome of L. monocytogenes is highly stable but open, suggesting an ability to adapt to new niches by generating or including new genetic information. The majority of gene-scale differences represented by the accessory genome resulted from nine hyper variable hotspots, a similar number of different prophages, three transposons (Tn916, Tn554, IS3-like), and two mobilizable islands. Only a subset of strains showed CRISPR/Cas bacteriophage resistance systems of different subtypes, suggesting a supplementary function in maintenance of chromosomal stability. Multiple phylogenetic branches of the genus Listeria imply long common histories of strains of each lineage as revealed by a SNP-based core genome tree highlighting the impact of small mutations for the evolution of species L. monocytogenes. Frequent loss or truncation of genes described to be vital for virulence or pathogenicity was confirmed as a recurring pattern, especially for strains belonging to lineages III and II. New candidate genes implicated in virulence function were predicted based on functional domains and phylogenetic distribution. A comparative analysis of small regulatory RNA candidates supports observations of a differential distribution of trans-encoded RNA, hinting at a diverse range of adaptations and regulatory impact. Conclusions This study determined commonly occurring hyper variable hotspots and mobile elements as primary effectors of quantitative gene-scale evolution of species L. monocytogenes, while gene decay and SNPs seem to represent major factors influencing long-term evolution. The discovery of common and disparately distributed genes considering lineages, serogroups, serotypes and strains of species L. monocytogenes will assist in diagnostic, phylogenetic and functional research, supported by the comparative genomic GECO-LisDB analysis server (http://bioinfo.mikrobio.med.uni-giessen.de/geco2lisdb).
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Affiliation(s)
- Carsten Kuenne
- Institute of Medical Microbiology, German Centre for Infection Research, Justus-Liebig-University, D-35392, Giessen, Germany
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Niland S, Ditkowski B, Parrandier D, Roth L, Augustin H, Eble JA. Rhodocetin-αβ-induced neuropilin-1-cMet association triggers restructuring of matrix contacts in endothelial cells. Arterioscler Thromb Vasc Biol 2013; 33:544-54. [PMID: 23288161 DOI: 10.1161/atvbaha.112.00006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
OBJECTIVE The snake venom component rhodocetin-αβ (RCαβ) stimulates endothelial cell motility in an α2β1 integrin-independent manner. We aimed to elucidate its cellular and molecular mechanisms. METHODS AND RESULTS We identified neuropilin-1 (Nrp1) as a novel target of RCαβ by protein-chemical methods. RCαβ and vascular endothelial growth factor (VEGF)-A avidly bind to Nrp1. Instead of acting as VEGF receptor 2 coreceptor, Nrp1 associates upon RCαβ treatment with cMet. Furthermore, cell-based ELISAs and kinase inhibitor studies showed that RCαβ induces phosphorylation of tyrosines 1234/1235 [corrected] and thus activation of cMet. Consequently, paxillin is phosphorylated at Y31, which is redistributed from streak-like focal adhesions to spot-like focal contacts at the cell perimeter, along with α2β1 integrin, thereby regulating cell-matrix interactions. Cortactin is abundant in the cell perimeter, where it is involved in the branching of the cortical actin network of lamellipodia, whereas tensile force-bearing actin stress fibers radiating from focal adhesions disappear together with zyxin, a focal adhesion marker, on RCαβ treatment. CONCLUSIONS Our data demonstrate that (1) Nrp1 is a novel target for venom components, such as RCαβ; (2) Nrp1 coupled to cMet regulates the type of cell-matrix interactions in a manner involving paxillin phosphorylation; and (3) altered cell-matrix interactions determine endothelial cell migration and cellular force management.
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Affiliation(s)
- Stephan Niland
- Center for Molecular Medicine, Vascular Matrix Biology, Excellence Cluster Cardio-Pulmonary System, Frankfurt University Hospital, Frankfurt, Germany
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Pizarro-Cerdá J, Kühbacher A, Cossart P. Entry of Listeria monocytogenes in mammalian epithelial cells: an updated view. Cold Spring Harb Perspect Med 2012; 2:2/11/a010009. [PMID: 23125201 DOI: 10.1101/cshperspect.a010009] [Citation(s) in RCA: 183] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Listeria monocytogenes is a bacterial pathogen that promotes its internalization into host epithelial cells. Interaction between the bacterial surface molecules InlA and InlB and their cellular receptors E-cadherin and Met, respectively, triggers the recruitment of endocytic effectors, the subversion of the phosphoinositide metabolism, and the remodeling of the actin cytoskeleton that lead to bacterial engulfment. Additional bacterial surface and secreted virulence factors also contribute to entry, albeit to a lesser extent. Here we review the increasing number of signaling effectors that are reported as being subverted by L. monocytogenes during invasion of cultured cell lines. We also update the current knowledge of the early steps of in vivo cellular infection, which, as shown recently, challenges previous concepts generated from in vitro data.
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Niemann HH. Structural basis of MET receptor dimerization by the bacterial invasion protein InlB and the HGF/SF splice variant NK1. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1834:2195-204. [PMID: 23123275 DOI: 10.1016/j.bbapap.2012.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 10/19/2012] [Accepted: 10/23/2012] [Indexed: 01/03/2023]
Abstract
The structural basis of ligand-induced dimerization of the receptor tyrosine kinase MET by its natural ligand hepatocyte growth factor/scatter factor (HGF/SF) is not well understood. However, interesting insight into the molecular mechanism of MET dimerization has emerged from crystal structures of MET in complex with a bacterial agonist, the invasion protein internalin B (InlB) from pathogenic Listeria monocytogenes. MET activation by InlB promotes uptake of bacteria into host cells. Structural and biophysical data suggest that InlB is monomeric on its own but dimerizes upon binding to the membrane-anchored MET receptor promoting the formation of a signaling active 2:2 complex. The dimerization interface is small and unusually located on the convex side of the curved InlB leucine-rich repeat (LRR) domain. As InlB does not dimerize in solution, the dimerization site could only be identified by studying packing contacts of InlB in various crystal forms and had to be proven by scrutinizing its biological relevance in cellular assays. InlB dimerization is thus an example of a low-affinity contact that appears irrelevant in solution but becomes physiologically significant in the context of 2-dimensional diffusion restricted to the membrane plane. The resulting 2:2 InlB:MET complex has an InlB dimer at its center with one MET molecule bound peripherally to each InlB. This model of ligand-mediated MET dimerization may serve as a blue-print to understand MET activation by NK1, a naturally occurring HGF/SF splice variant and MET agonist. Crystal structures of NK1 repeatedly show a NK1 dimer, in which residues implicated in MET-binding are located on the outside. Thus, MET dimerization by NK1 may also be ligand-mediated with a NK1 dimer at the center of the 2:2 complex with one MET molecule bound peripherally to each NK1. This article is part of a Special Issue entitled: Emerging recognition and activation mechanisms of receptor tyrosine kinases.
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Affiliation(s)
- Hartmut H Niemann
- Department of Chemistry and Center for Biotechnology (CeBiTec), Bielefeld University, 33501 Bielefeld, Germany.
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Niemann HH, Gherardi E, Bleymüller WM, Heinz DW. Engineered variants of InlB with an additional leucine-rich repeat discriminate between physiologically relevant and packing contacts in crystal structures of the InlB:MET complex. Protein Sci 2012; 21:1528-39. [PMID: 22887347 PMCID: PMC3526994 DOI: 10.1002/pro.2142] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/01/2012] [Accepted: 08/06/2012] [Indexed: 11/07/2022]
Abstract
The physiological relevance of contacts in crystal lattices often remains elusive. This was also the case for the complex between the invasion protein internalin B (InlB) from Listeria monocytogenes and its host cell receptor, the human receptor tyrosine kinase (RTK) MET. InlB is a MET agonist and induces bacterial host cell invasion. Activation of RTKs generally involves ligand-induced dimerization of the receptor ectodomain. The two currently available crystal structures of the InlB:MET complex show the same arrangement of InlB and MET in a 1:1 complex, but different dimeric 2:2 assemblies. Only one of these 2:2 assemblies is predicted to be stable by a computational procedure. This assembly is mainly stabilized by a contact between the Cap domain of InlB from one and the Sema domain of MET from another 1:1 complex. Here, we probe the physiological relevance of this interaction. We generated variants of the leucine-rich repeat (LRR) protein InlB by inserting an additional repeat between the first and the second LRR. This should allow formation of the 1:1 complex but disrupt the potential 2:2 complex involving the Cap-Sema contact due to steric distortions. A crystal structure of one of the engineered proteins showed that it folded properly. Binding affinity to MET was comparable to that of wild-type InlB. The InlB variant induced MET phosphorylation and cell scatter like wild-type InlB. These results suggest that the Cap-Sema interaction is not physiologically relevant and support the previously proposed assembly, in which a 2:2 InlB:MET complex is built around a ligand dimer.
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Affiliation(s)
- Hartmut H Niemann
- Department of Chemistry, Bielefeld University, 33501 Bielefeld, Germany.
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Juge N. Microbial adhesins to gastrointestinal mucus. Trends Microbiol 2011; 20:30-9. [PMID: 22088901 DOI: 10.1016/j.tim.2011.10.001] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 09/30/2011] [Accepted: 10/14/2011] [Indexed: 01/04/2023]
Abstract
The gastrointestinal tract (GIT) is lined by a layer of mucus formed by mucin glycoproteins. This layer constitutes a physical and chemical barrier between the intestinal contents and the underlying epithelia. In addition to this protective role, mucins harbor glycan-rich domains that provide preferential binding sites for pathogens and commensal bacteria. Although mucus-microbial interactions in the GIT play a crucial role in determining the outcome of relationships of both commensal and pathogens with the host, the adhesins and ligands involved in the interaction are poorly delineated. This review focuses on the current knowledge of microbial adhesins to gastrointestinal mucus and mucus components.
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Affiliation(s)
- Nathalie Juge
- Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
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