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Wang M, Li X, Cavallo FM, Yedavally H, Piersma S, Raineri EJM, Vera Murguia E, Kuipers J, Zhang Z, van Dijl JM, Buist G. Functional profiling of CHAP domain-containing peptidoglycan hydrolases of Staphylococcus aureus USA300 uncovers potential targets for anti-staphylococcal therapies. Int J Med Microbiol 2024; 316:151632. [PMID: 39142057 DOI: 10.1016/j.ijmm.2024.151632] [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: 04/03/2024] [Revised: 07/16/2024] [Accepted: 08/04/2024] [Indexed: 08/16/2024] Open
Abstract
The bacterial pathogen Staphylococcus aureus employs a thick cell wall for protection against physical and chemical insults. This wall requires continuous maintenance to ensure strength and barrier integrity, but also to permit bacterial growth and division. The main cell wall component is peptidoglycan. Accordingly, the bacteria produce so-called peptidoglycan hydrolases (PGHs) that cleave glycan strands to facilitate growth, cell wall remodelling, separation of divided cells and release of exported proteins into the extracellular milieu. A special class of PGHs contains so-called 'cysteine, histidine-dependent amidohydrolase/peptidase' (CHAP) domains. In the present study, we profiled the roles of 11 CHAP PGHs encoded by the core genome of S. aureus USA300 LAC. Mutant strains lacking individual CHAP PGHs were analysed for growth, cell morphology, autolysis, and invasion and replication inside human lung epithelial cells. The results show that several investigated CHAP PGHs contribute to different extents to extracellular and intracellular growth and replication of S. aureus, septation of dividing cells, daughter cell separation once the division process is completed, autolysis and biofilm formation. In particular, the CHAP PGHs Sle1 and SAUSA300_2253 control intracellular staphylococcal replication and the resistance to β-lactam antibiotics like oxacillin. This makes the S. aureus PGHs in general, and the Sle1 and SAUSA300_2253 proteins in particular, attractive targets for future prophylactic or therapeutic anti-staphylococcal interventions. Alternatively, these cell surface-exposed enzymes, or particular domains of these enzymes, could be applied in innovative anti-staphylococcal therapies.
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Affiliation(s)
- Min Wang
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, Groningen 9700 RB, the Netherlands
| | - Xiaofang Li
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, Groningen 9700 RB, the Netherlands
| | - Francis M Cavallo
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, Groningen 9700 RB, the Netherlands
| | - Harita Yedavally
- Department of Nanomedicine and Drug Targeting, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, the Netherlands
| | - Sjouke Piersma
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, Groningen 9700 RB, the Netherlands
| | - Elisa J M Raineri
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, Groningen 9700 RB, the Netherlands
| | - Elias Vera Murguia
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, Groningen 9700 RB, the Netherlands
| | - Jeroen Kuipers
- Department of Biomedical Sciences, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Zhenhua Zhang
- Genomics Coordination Center, University of Groningen and University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713 AV, the Netherlands
| | - Jan Maarten van Dijl
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, Groningen 9700 RB, the Netherlands.
| | - Girbe Buist
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, Groningen 9700 RB, the Netherlands.
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Zhang R, Jia Y, Scaffidi SJ, Madsen JJ, Yu W. Signal peptidase SpsB coordinates staphylococcal cell cycle, surface protein septal trafficking and LTA synthesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.20.608893. [PMID: 39229149 PMCID: PMC11370438 DOI: 10.1101/2024.08.20.608893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Many cell wall anchored surface proteins of Gram-positive bacteria harbor a highly conserved YSIRK/G-S signal peptide (SPYSIRK+), which deposits surface protein precursors at the cell division septum where they are subsequently anchored to septal peptidoglycan. Previously we identified that LtaS-mediated lipoteichoic acid (LTA) synthesis regulates septal trafficking of YSIRK+ proteins in S. aureus. Interestingly, both LtaS and SPYSIRK+ are cleaved by the signal peptidase SpsB, but the biological implications remain unclear. Here we show that SpsB is required for cleaving SPSpA(YSIRK+) of staphylococcal surface protein A (SpA). Depletion of spsB not only diminished SPSpA processing but also abolished SpA septal localization. The mis-localization is attributed to the cleavage activity of SpsB, as an A37P mutation of SPSpA that disrupted SpsB cleavage also abrogated SpA septal localization. Strikingly, depletion of spsB led to aberrant cell morphology, cell cycle arrest and daughter cell separation defects. Localization studies showed that SpsB predominantly localized at the septum of dividing staphylococcal cells. Finally, we show that SpsB spatially regulates LtaS as spsB depletion enriched LtaS at the septum. Collectively, the data suggest a new dual-mechanism model mediated by SpsB: the abundant YSIRK+ proteins are efficiently processed by septal localized SpsB; SpsB cleaves LtaS at the septum, which spatially regulates LtaS activity contributing to YSIRK+ proteins septal trafficking. The study identifies SpsB as a novel and key regulator orchestrating protein secretion, cell cycle and cell envelope biogenesis.
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Affiliation(s)
- Ran Zhang
- Department of Molecular Biosciences, College of Arts and Sciences, University of South Florida, Tampa, Florida 33620, United States of America
| | - Yaosheng Jia
- Department of Molecular Biosciences, College of Arts and Sciences, University of South Florida, Tampa, Florida 33620, United States of America
| | - Salvatore J Scaffidi
- Department of Molecular Biosciences, College of Arts and Sciences, University of South Florida, Tampa, Florida 33620, United States of America
| | - Jesper J Madsen
- Department of Molecular Medicine, Morsani College of Medicine; Center for Global Health and Infectious Diseases Research, Global and Planetary Health, College of Public Health, University of South Florida, Tampa, Florida 33620, United States of America
| | - Wenqi Yu
- Department of Molecular Biosciences, College of Arts and Sciences, University of South Florida, Tampa, Florida 33620, United States of America
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3
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Ibrahim AM, Azam MS, Schneewind O, Missiakas D. Processing of LtaS restricts LTA assembly and YSIRK preprotein trafficking into Staphylococcus aureus cross-walls. mBio 2024; 15:e0285223. [PMID: 38174934 PMCID: PMC10865820 DOI: 10.1128/mbio.02852-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 10/31/2023] [Indexed: 01/05/2024] Open
Abstract
Septal membranes of Staphylococcus aureus serve as the site of secretion for precursors endowed with the YSIRK motif. Depletion of ltaS, a gene required for lipoteichoic acid (LTA) synthesis, results in the loss of restricted trafficking of YSIRK precursors to septal membranes. Here, we seek to understand the mechanism that ties LTA assembly and trafficking of YSIRK precursors. We confirm that catalytically inactive lipoteichoic acid synthase (LtaS)T300A does not support YSIRK precursor trafficking to septa. We hypothesize that the enzyme's reactants [gentiobiosyldiacylglycerol (Glc2-DAG) and phosphatidylglycerol (PG)] or products [LTA and diacylglycerol (DAG)], not LtaS, must drive this process. Indeed, we observe that septal secretion of the staphylococcal protein A YSIRK precursor is lost in ypfP and ltaA mutants that produce glycerophosphate polymers [poly(Gro-P)] without the Glc2-DAG lipid anchor. These mutants display longer poly(Gro-P) chains, implying enhanced PG consumption and DAG production. Our experiments also reveal that in the absence of Glc2-DAG, the processing of LtaS to the extracellular catalytic domain, eLtaS, is impaired. Conversely, LTA polymerization is delayed in a strain producing LtaSS218P, a variant processed more slowly than LtaS. We conclude that Glc2-DAG binding to the enzyme couples catalysis by LtaS and the physical release of eLtaS. We propose a model for the temporal and localized assembly of LTA into cross-walls. When LtaS is not processed in a timely manner, eLtaS no longer diffuses upon daughter cell splitting, LTA assembly continues, and the unique septal-lipid pool, PG over DAG ratio, is not established. This results in profound physiological changes in S. aureus cells, including the inability to restrict the secretion of YSIRK precursors at septal membranes.IMPORTANCEIn Staphylococcus aureus, peptidoglycan is assembled at the septum. Dedicated cell division proteins coordinate septal formation and the fission of daughter cells. Lipoteichoic acid (LTA) assembly and trafficking of preproteins with a YSIRK motif also occur at the septum. This begs the question as to whether cell division components also recruit these two pathways. This study shows that the processing of lipoteichoic acid synthase (LtaS) to extracellular LtaS by signal peptidase is regulated by gentiobiosyldiacylglycerol (Glc2-DAG), the priming substrate for LTA assembly. A model is proposed whereby a key substrate controls the temporal and spatial activity of an enzyme. In turn, this mechanism enables the establishment of a unique and transient lipid pool that defines septal membranes as a targeting site for the secretion of YSIRK preproteins.
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Affiliation(s)
- Amany M. Ibrahim
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, Illinois, USA
- Department of Microbiology and Immunology, Faculty of Pharmacy, Sinai University, Arish, Egypt
| | - Muhammad S. Azam
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, Illinois, USA
| | - Olaf Schneewind
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, Illinois, USA
| | - Dominique Missiakas
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, Illinois, USA
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Madsen JJ, Yu W. Dynamic Nature of Staphylococcus aureus Type I Signal Peptidases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.23.576923. [PMID: 38328037 PMCID: PMC10849702 DOI: 10.1101/2024.01.23.576923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Molecular dynamics simulations are used to interrogate the dynamic nature of Staphylococcus aureus Type I signal peptidases, SpsA and SpsB, including the impact of the P29S mutation of SpsB. Fluctuations and plasticity- rigidity characteristics vary among the proteins, particularly in the extracellular domain. Intriguingly, the P29S mutation, which influences susceptibility to arylomycin antibiotics, affect the mechanically coupled motions in SpsB. The integrity of the active site is crucial for catalytic competency, and variations in sampled structural conformations among the proteins are consistent with diverse peptidase capabilities. We also explored the intricate interactions between the proteins and the model S. aureus membrane. It was observed that certain membrane-inserted residues in the loop around residue 50 (50s) and C-terminal loops, beyond the transmembrane domain, give rise to direct interactions with lipids in the bilayer membrane. Our findings are discussed in the context of functional knowledge about these signal peptidases, offering additional understanding of dynamic aspects relevant to some cellular processes with potential implications for drug targeting strategies.
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Affiliation(s)
- Jesper J. Madsen
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States of America
- Center for Global Health and Infectious Diseases Research, Global and Planetary Health, College of Public Health, University of South Florida, Tampa, Florida 33612, United States of America
| | - Wenqi Yu
- Department of Molecular Biosciences, College of Arts and Sciences, University of South Florida, Tampa, Florida 33612, United States of America
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5
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Liu S, Chen H, Xu F, Chen F, Yin Y, Zhang X, Tu S, Wang H. Unravelling staphylococcal small-colony variants in cardiac implantable electronic device infections: clinical characteristics, management, and genomic insights. Front Cell Infect Microbiol 2024; 13:1321626. [PMID: 38259974 PMCID: PMC10800868 DOI: 10.3389/fcimb.2023.1321626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 12/11/2023] [Indexed: 01/24/2024] Open
Abstract
Objectives Staphylococcal small-colony variants (SCVs) are common in cardiac implantable electronic device (CIED) infections. This is the first retrospective and multi-case study on CIED infections due to staphylococcal SCVs, aiming to provide a theoretical basis for the clinical management of CIED and device-related infections caused by staphylococcal SCVs. Methods Ninety patients with culture positive CIED infections were enrolled between 2021 and 2022. We compared the demographic and clinical characteristics of patients with and without SCVs and performed genomic studies on SCVs isolates. Results Compared to patients without SCVs, those with SCVs had a longer primary pacemaker implantation time and were more likely to have a history of device replacement and infection. They showed upregulated inflammatory indicators, especially higher NEUT% (52.6 vs. 26.8%, P = 0.032) and they had longer hospital stays (median 13 vs. 12 days, P = 0.012). Comparative genomics analysis was performed on Staphylococcus epidermidis wild-type and SCVs. Some genes were identified, including aap, genes encoding adhesin, CHAP domain-containing protein, LPXTG cell wall anchor domain-containing protein, and YSIRK-type signal peptide-containing protein. Conclusion Staphylococcal SCVs affect the clinical characteristics of CIED infections. The process of staphylococcal SCVs adherence, biofilm formation, and interaction with neutrophils play a vital role.
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Affiliation(s)
- Si Liu
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Hongbin Chen
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Fangjie Xu
- Department of Clinical Laboratory, Urumqi Friendship Hospital, Urumqi, China
| | - Fengning Chen
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Yuyao Yin
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Xiaoyang Zhang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Shangyu Tu
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Hui Wang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
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6
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Kadeřábková N, Mahmood AJS, Furniss RCD, Mavridou DAI. Making a chink in their armor: Current and next-generation antimicrobial strategies against the bacterial cell envelope. Adv Microb Physiol 2023; 83:221-307. [PMID: 37507160 PMCID: PMC10517717 DOI: 10.1016/bs.ampbs.2023.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Gram-negative bacteria are uniquely equipped to defeat antibiotics. Their outermost layer, the cell envelope, is a natural permeability barrier that contains an array of resistance proteins capable of neutralizing most existing antimicrobials. As a result, its presence creates a major obstacle for the treatment of resistant infections and for the development of new antibiotics. Despite this seemingly impenetrable armor, in-depth understanding of the cell envelope, including structural, functional and systems biology insights, has promoted efforts to target it that can ultimately lead to the generation of new antibacterial therapies. In this article, we broadly overview the biology of the cell envelope and highlight attempts and successes in generating inhibitors that impair its function or biogenesis. We argue that the very structure that has hampered antibiotic discovery for decades has untapped potential for the design of novel next-generation therapeutics against bacterial pathogens.
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Affiliation(s)
- Nikol Kadeřábková
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - Ayesha J S Mahmood
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - R Christopher D Furniss
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Despoina A I Mavridou
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States; John Ring LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, TX, United States.
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7
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Salamaga B, Turner RD, Elsarmane F, Galley NF, Kulakauskas S, Mesnage S. A moonlighting role for LysM peptidoglycan binding domains underpins Enterococcus faecalis daughter cell separation. Commun Biol 2023; 6:428. [PMID: 37072531 PMCID: PMC10113225 DOI: 10.1038/s42003-023-04808-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 04/04/2023] [Indexed: 04/20/2023] Open
Abstract
Control of cell size and morphology is of paramount importance for bacterial fitness. In the opportunistic pathogen Enterococcus faecalis, the formation of diplococci and short cell chains facilitates innate immune evasion and dissemination in the host. Minimisation of cell chain size relies on the activity of a peptidoglycan hydrolase called AtlA, dedicated to septum cleavage. To prevent autolysis, AtlA activity is tightly controlled, both temporally and spatially. Here, we show that the restricted localization of AtlA at the septum occurs via an unexpected mechanism. We demonstrate that the C-terminal LysM domain that allows the enzyme to bind peptidoglycan is essential to target this enzyme to the septum inside the cell before its translocation across the membrane. We identify a membrane-bound cytoplasmic protein partner (called AdmA) involved in the recruitment of AtlA via its LysM domains. This work reveals a moonlighting role for LysM domains, and a mechanism evolved to restrict the subcellular localization of a potentially lethal autolysin to its site of action.
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Affiliation(s)
| | - Robert D Turner
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - Fathe Elsarmane
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - Nicola F Galley
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
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Leonard AC, Goncheva MI, Gilbert SE, Shareefdeen H, Petrie LE, Thompson LK, Khursigara CM, Heinrichs DE, Cox G. Autolysin-mediated peptidoglycan hydrolysis is required for the surface display of Staphylococcus aureus cell wall-anchored proteins. Proc Natl Acad Sci U S A 2023; 120:e2301414120. [PMID: 36920922 PMCID: PMC10041135 DOI: 10.1073/pnas.2301414120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 02/14/2023] [Indexed: 03/16/2023] Open
Abstract
Peptidoglycan hydrolases, or autolysins, play a critical role in cell wall remodeling and degradation, facilitating bacterial growth, cell division, and cell separation. In Staphylococcus aureus, the so-called "major" autolysin, Atl, has long been associated with host adhesion; however, the molecular basis underlying this phenomenon remains understudied. To investigate, we used the type V glycopeptide antibiotic complestatin, which binds to peptidoglycan and blocks the activity of autolysins, as a chemical probe of autolysin function. We also generated a chromosomally encoded, catalytically inactive variant of the Atl enzyme. Autolysin-mediated peptidoglycan hydrolysis, in particular Atl-mediated daughter cell separation, was shown to be critical for maintaining optimal surface levels of S. aureus cell wall-anchored proteins, including the fibronectin-binding proteins (FnBPs) and protein A (Spa). As such, disrupting autolysin function reduced the affinity of S. aureus for host cell ligands, and negatively impacted early stages of bacterial colonization in a systemic model of S. aureus infection. Phenotypic studies revealed that Spa was sequestered at the septum of complestatin-treated cells, highlighting that autolysins are required to liberate Spa during cell division. In summary, we reveal the hydrolytic activities of autolysins are associated with the surface display of S. aureus cell wall-anchored proteins. We demonstrate that by blocking autolysin function, type V glycopeptide antibiotics are promising antivirulence agents for the development of strategies to control S. aureus infections.
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Affiliation(s)
- Allison C. Leonard
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, GuelphONN1G 2W1, Canada
| | - Mariya I. Goncheva
- Department of Microbiology and Immunology, University of Western Ontario, LondonONN6A 5C1, Canada
| | - Stephanie E. Gilbert
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, GuelphONN1G 2W1, Canada
| | - Hiba Shareefdeen
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, GuelphONN1G 2W1, Canada
| | - Laurenne E. Petrie
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, GuelphONN1G 2W1, Canada
| | - Laura K. Thompson
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, GuelphONN1G 2W1, Canada
| | - Cezar M. Khursigara
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, GuelphONN1G 2W1, Canada
| | - David E. Heinrichs
- Department of Microbiology and Immunology, University of Western Ontario, LondonONN6A 5C1, Canada
| | - Georgina Cox
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, GuelphONN1G 2W1, Canada
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Sugimoto S, Kinjo Y. Instantaneous Clearing of Biofilm (iCBiofilm): an optical approach to revisit bacterial and fungal biofilm imaging. Commun Biol 2023; 6:38. [PMID: 36690667 PMCID: PMC9870912 DOI: 10.1038/s42003-022-04396-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 12/21/2022] [Indexed: 01/24/2023] Open
Abstract
Whole-biofilm imaging at single-cell resolution is necessary for system-level analysis of cellular heterogeneity, identification of key matrix component functions and response to immune cells and antimicrobials. To this end, we developed a whole-biofilm clearing and imaging method, termed instantaneous clearing of biofilm (iCBiofilm). iCBiofilm is a simple, rapid, and efficient method involving the immersion of biofilm samples in a refractive index-matching medium, enabling instant whole-biofilm imaging with confocal laser scanning microscopy. We also developed non-fixing iCBiofilm, enabling live and dynamic imaging of biofilm development and actions of antimicrobials. iCBiofilm is applicable for multicolor imaging of fluorescent proteins, immunostained matrix components, and fluorescence labeled cells in biofilms with a thickness of several hundred micrometers. iCBiofilm is scalable from bacterial to fungal biofilms and can be used to observe biofilm-neutrophil interactions. iCBiofilm therefore represents an important advance for examining the dynamics and functions of biofilms and revisiting bacterial and fungal biofilm formation.
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Affiliation(s)
- Shinya Sugimoto
- Department of Bacteriology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
- Jikei Center for Biofilm Science and Technology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
| | - Yuki Kinjo
- Department of Bacteriology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461, Japan
- Jikei Center for Biofilm Science and Technology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461, Japan
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10
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Grousd JA, Dresden BP, Riesmeyer AM, Cooper VS, Bomberger JM, Richardson AR, Alcorn JF. Novel Requirement for Staphylococcal Cell Wall-Anchored Protein SasD in Pulmonary Infection. Microbiol Spectr 2022; 10:e0164522. [PMID: 36040164 PMCID: PMC9603976 DOI: 10.1128/spectrum.01645-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 08/16/2022] [Indexed: 02/04/2023] Open
Abstract
Staphylococcus aureus can complicate preceding viral infections, including influenza virus. A bacterial infection combined with a preceding viral infection, known as superinfection, leads to worse outcomes than a single infection. Most of the pulmonary infection literature focuses on the changes in immune responses to bacteria between homeostatic and virally infected lungs. However, it is unclear how much of an influence bacterial virulence factors have in single or superinfection. Staphylococcal species express a broad range of cell wall-anchored proteins (CWAs) that have roles in host adhesion, nutrient acquisition, and immune evasion. We screened the importance of these CWAs using mutants lacking individual CWAs in vivo in both bacterial pneumonia and influenza superinfection. In bacterial pneumonia, the lack of individual CWAs leads to various decreases in bacterial burden, lung damage, and immune infiltration into the lung. However, the presence of a preceding influenza infection partially abrogates the requirement for CWAs. In the screen, we found that the uncharacterized CWA S. aureus surface protein D (SasD) induced changes in both inflammatory and homeostatic lung markers. We further characterized a SasD mutant (sasD A50.1) in the context of pneumonia. Mice infected with sasD A50.1 have decreased bacterial burden, inflammatory responses, and mortality compared to wild-type S. aureus. Mice also have reduced levels of interleukin-1β (IL-1β), likely derived from macrophages. Reductions in IL-1β transcript levels as well as increased macrophage viability point at differences in cell death pathways. These data identify a novel virulence factor for S. aureus that influences inflammatory signaling within the lung. IMPORTANCE Staphylococcus aureus is a common commensal bacterium that can cause severe infections, such as pneumonia. In the lung, viral infections increase the risk of staphylococcal pneumonia, leading to combined infections known as superinfections. The most common virus associated with S. aureus pneumonia is influenza, and superinfections lead to worse patient outcomes than either infection alone. While there is much known about how the immune system differs between healthy and virally infected lungs, the role of bacterial virulence factors in single and superinfection is less understood. The significance of our research is identifying bacterial components that play a role in the initiation of lung injury, which could lead to future therapies to prevent pulmonary single or superinfection with S. aureus.
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Affiliation(s)
- Jennifer A. Grousd
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Pediatrics, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Brooke P. Dresden
- Department of Pediatrics, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Abigail M. Riesmeyer
- Department of Pediatrics, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Vaughn S. Cooper
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jennifer M. Bomberger
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anthony R. Richardson
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - John F. Alcorn
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Pediatrics, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
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11
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Berry KA, Verhoef MTA, Leonard AC, Cox G. Staphylococcus aureus adhesion to the host. Ann N Y Acad Sci 2022; 1515:75-96. [PMID: 35705378 DOI: 10.1111/nyas.14807] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Staphylococcus aureus is a pathobiont capable of colonizing and infecting most tissues within the human body, resulting in a multitude of different clinical outcomes. Adhesion of S. aureus to the host is crucial for both host colonization and the establishment of infections. Underlying the pathogen's success is a complex and diverse arsenal of adhesins. In this review, we discuss the different classes of adhesins, including a consideration of the various adhesion sites throughout the body and the clinical outcomes of each infection type. The development of therapeutics targeting the S. aureus host-pathogen interaction is a relatively understudied area. Due to the increasing global threat of antimicrobial resistance, it is crucial that innovative and alternative approaches are considered. Neutralizing virulence factors, through the development of antivirulence agents, could reduce bacterial pathogenicity and the ever-increasing burden of S. aureus infections. This review provides insight into potentially efficacious adhesion-associated targets for the development of novel decolonizing and antivirulence strategies.
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Affiliation(s)
- Kirsten A Berry
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Mackenzie T A Verhoef
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Allison C Leonard
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Georgina Cox
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada
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12
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Wang M, Buist G, van Dijl JM. Staphylococcus aureus cell wall maintenance - the multifaceted roles of peptidoglycan hydrolases in bacterial growth, fitness, and virulence. FEMS Microbiol Rev 2022; 46:6604383. [PMID: 35675307 PMCID: PMC9616470 DOI: 10.1093/femsre/fuac025] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/22/2022] [Accepted: 05/25/2022] [Indexed: 01/07/2023] Open
Abstract
Staphylococcus aureus is an important human and livestock pathogen that is well-protected against environmental insults by a thick cell wall. Accordingly, the wall is a major target of present-day antimicrobial therapy. Unfortunately, S. aureus has mastered the art of antimicrobial resistance, as underscored by the global spread of methicillin-resistant S. aureus (MRSA). The major cell wall component is peptidoglycan. Importantly, the peptidoglycan network is not only vital for cell wall function, but it also represents a bacterial Achilles' heel. In particular, this network is continuously opened by no less than 18 different peptidoglycan hydrolases (PGHs) encoded by the S. aureus core genome, which facilitate bacterial growth and division. This focuses attention on the specific functions executed by these enzymes, their subcellular localization, their control at the transcriptional and post-transcriptional levels, their contributions to staphylococcal virulence and their overall importance in bacterial homeostasis. As highlighted in the present review, our understanding of the different aspects of PGH function in S. aureus has been substantially increased over recent years. This is important because it opens up new possibilities to exploit PGHs as innovative targets for next-generation antimicrobials, passive or active immunization strategies, or even to engineer them into effective antimicrobial agents.
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Affiliation(s)
- Min Wang
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands
| | | | - Jan Maarten van Dijl
- Corresponding author: Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, HPC EB80, 9700 RB Groningen, the Netherlands, Tel. +31-50-3615187; Fax. +31-50-3619105; E-mail:
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13
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Schiffer CJ, Schaudinn C, Ehrmann MA, Vogel RF. SxsA, a novel surface protein mediating cell aggregation and adhesive biofilm formation of Staphylococcus xylosus. Mol Microbiol 2022; 117:986-1001. [PMID: 35072960 DOI: 10.1111/mmi.14884] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/20/2022] [Accepted: 01/20/2022] [Indexed: 11/28/2022]
Abstract
Biofilm formation of staphylococci has been an emerging field of research for many years. However, the underlying molecular mechanisms are still not fully understood, and vary widely between species and strains. The aim of this study was to identify new effectors impacting biofilm formation of two Staphylococcus (S.) xylosus strains. We identified a novel surface protein conferring cell aggregation, adherence to abiotic surfaces and biofilm formation. The S. xylosus surface protein A (SxsA) is a large protein occurring in variable sizes. It lacks sequence similarity to other staphylococcal surface proteins but shows similar structural domain organization and functional features. Upon deletion of sxsA, adherence of S. xylosus strain TMW 2.1523 to abiotic surfaces was completely abolished, and significantly reduced in TMW 2.1023. Macro- and microscopic aggregation assays further showed that TMW 2.1523 sxsA mutants exhibit reduced cell aggregation compared to the wildtype. Comparative genomic analysis revealed that sxsA is part of the core genome of S. xylosus, S. paraxylosus and S. nepalensis and additionally encoded in a small group of S. cohnii and S. saprophyticus strains. This study provides insights into protein-mediated biofilm formation of S. xylosus and identifies a new cell wall-associated protein influencing cell aggregation and biofilm formation.
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Affiliation(s)
- Carolin J Schiffer
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Freising, Germany.,Lehrstuhl für Mikrobiologie, Technische Universität München, Freising, Germany
| | - Christoph Schaudinn
- Advanced Light and Electron Microscopy, Robert Koch Institute, Berlin, Germany
| | - Matthias A Ehrmann
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Freising, Germany.,Lehrstuhl für Mikrobiologie, Technische Universität München, Freising, Germany
| | - Rudi F Vogel
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Freising, Germany
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14
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Bap-Independent Biofilm Formation in Staphylococcus xylosus. Microorganisms 2021; 9:microorganisms9122610. [PMID: 34946212 PMCID: PMC8708073 DOI: 10.3390/microorganisms9122610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 11/17/2022] Open
Abstract
The biofilm associated protein (Bap) is recognised as the essential component for biofilm formation in Staphylococcus aureus V329 and has been predicted as important for other species as well. Although Bap orthologs are also present in most S. xylosus strains, their contribution to biofilm formation has not yet been demonstrated. In this study, different experimental approaches were used to elucidate the effect of Bap on biofilm formation in S. xylosus and the motif structure of two biofilm-forming S. xylosus strains TMW 2.1023 and TMW 2.1523 was compared to Bap of S. aureus V329. We found that despite an identical structural arrangement into four regions, Bap from S. xylosus differs in key factors to Bap of S. aureus, i.e., isoelectric point of aggregation prone Region B, protein homology and type of repeats. Disruption of bap had no effect on aggregation behavior of selected S. xylosus strains and biofilm formation was unaffected (TMW 2.1023) or at best slightly reduced under neutral conditions (TMW 2.1523). Further, we could not observe any typical characteristics of a S. aureus Bap-positive phenotype such as functional impairment by calcium addition and rough colony morphology on congo red agar (CRA). A dominating role of Bap in cell aggregation and biofilm formation as reported mainly for S. aureus V329 was not observed. In contrast, this work demonstrates that functions of S. aureus Bap cannot easily be extrapolated to S. xylosus Bap, which appears as non-essential for biofilm formation in this species. We therefore suggest that biofilm formation in S. xylosus follows different and multifactorial mechanisms.
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15
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The cell envelope of Staphylococcus aureus selectively controls the sorting of virulence factors. Nat Commun 2021; 12:6193. [PMID: 34702812 PMCID: PMC8548510 DOI: 10.1038/s41467-021-26517-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 10/05/2021] [Indexed: 11/08/2022] Open
Abstract
Staphylococcus aureus bi-component pore-forming leukocidins are secreted toxins that directly target and lyse immune cells. Intriguingly, one of the leukocidins, Leukocidin AB (LukAB), is found associated with the bacterial cell envelope in addition to secreted into the extracellular milieu. Here, we report that retention of LukAB on the bacterial cells provides S. aureus with a pre-synthesized active toxin that kills immune cells. On the bacteria, LukAB is distributed as discrete foci in two distinct compartments: membrane-proximal and surface-exposed. Through genetic screens, we show that a membrane lipid, lysyl-phosphatidylglycerol (LPG), and lipoteichoic acid (LTA) contribute to LukAB deposition and release. Furthermore, by studying non-covalently surface-bound proteins we discovered that the sorting of additional exoproteins, such as IsaB, Hel, ScaH, and Geh, are also controlled by LPG and LTA. Collectively, our study reveals a multistep secretion system that controls exoprotein storage and protein translocation across the S. aureus cell wall.
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16
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Wysocka A, Jagielska E, Łężniak Ł, Sabała I. Two New M23 Peptidoglycan Hydrolases With Distinct Net Charge. Front Microbiol 2021; 12:719689. [PMID: 34630350 PMCID: PMC8498115 DOI: 10.3389/fmicb.2021.719689] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/16/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial peptidoglycan hydrolases play an essential role in cell wall metabolism during bacterial growth, division, and elongation (autolysins) or in the elimination of closely related species from the same ecological niche (bacteriocins). Most studies concerning the peptidoglycan hydrolases present in Gram-positive bacteria have focused on clinically relevant Staphylococcus aureus or the model organism Bacillus subtilis, while knowledge relating to other species remains limited. Here, we report two new peptidoglycan hydrolases from the M23 family of metallopeptidases derived from the same staphylococcal species, Staphylococcus pettenkoferi. They share modular architecture, significant sequence identity (60%), catalytic and binding residue conservation, and similar modes of activation, but differ in gene distribution, putative biological role, and, strikingly, in their isoelectric points (pIs). One of the peptides has a high pI, similar to that reported for all M23 peptidases evaluated to date, whereas the other displays a low pI, a unique feature among M23 peptidases. Consequently, we named them SpM23_B (Staphylococcus pettenkoferi M23 "Basic") and SpM23_A (Staphylococcus pettenkoferi M23 "Acidic"). Using genetic and biochemical approaches, we have characterized these two novel lytic enzymes, both in vitro and in their physiological context. Our study presents a detailed characterization of two novel and clearly distinct peptidoglycan hydrolases to understand their role in bacterial physiology.
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Affiliation(s)
- Alicja Wysocka
- International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Elżbieta Jagielska
- International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Łukasz Łężniak
- International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Izabela Sabała
- International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
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17
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Kumar NG, Contaifer D, Wijesinghe DS, Jefferson KK. Staphylococcus aureus Lipase 3 (SAL3) is a surface-associated lipase that hydrolyzes short chain fatty acids. PLoS One 2021; 16:e0258106. [PMID: 34618844 PMCID: PMC8496776 DOI: 10.1371/journal.pone.0258106] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 09/20/2021] [Indexed: 11/18/2022] Open
Abstract
Bacterial lipases play important roles during infection. The Staphylococcus aureus genome contains several genes that encode well-characterized lipases and several genes predicted to encode lipases or esterases for which the function has not yet been established. In this study, we sought to define the function of an uncharacterized S. aureus protein, and we propose the annotation S. aureus lipase 3 (SAL3) (SAUSA300_0641). We confirmed that SAL3 is a lipase and that it is surface associated and secreted through an unknown mechanism. We determined that SAL3 specifically hydrolyzes short chain (4-carbon and fewer) fatty acids and specifically binds negatively charged lipids including phosphatidic acid, phosphatidylinositol phosphate, and phosphatidylglycerol, which is the most abundant lipid in the staphylococcal cell membrane. Mutating the catalytic triad S66-A, D167-A, S168-A, and H301-A in the recombinant protein abolished lipase activity without altering binding to host lipid substrates. Taken together we report the discovery of a novel lipase from S. aureus specific to short chain fatty acids with yet to be determined roles in host pathogen interactions.
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Affiliation(s)
- Naren Gajenthra Kumar
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Daniel Contaifer
- Department of Pharmacotherapy and Outcomes Sciences, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Dayanjan S. Wijesinghe
- Department of Pharmacotherapy and Outcomes Sciences, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Kimberly K. Jefferson
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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18
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Bai Q, Ma J, Zhang Z, Zhong X, Pan Z, Zhu Y, Zhang Y, Wu Z, Liu G, Yao H. YSIRK-G/S-directed translocation is required for Streptococcus suis to deliver diverse cell wall anchoring effectors contributing to bacterial pathogenicity. Virulence 2021; 11:1539-1556. [PMID: 33138686 PMCID: PMC7644249 DOI: 10.1080/21505594.2020.1838740] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The Streptococcus suis serotype 2 (SS2) is a significant zoonotic pathogen that is responsible for various swine diseases, even causing cytokine storms of Streptococcal toxic shock-like syndromes amongst human. Cell wall anchoring proteins with a C-terminal LPxTG are considered to play vital roles during SS2 infection; however, their exporting mechanism across cytoplasmic membranes has remained vague. This study found that YSIRK-G/S was involved in the exportation of LPxTG-anchoring virulence factors MRP and SspA in virulent SS2 strain ZY05719. The whole-genome analysis indicated that diverse LPxTG proteins fused with an N-terminal YSIRK-G/S motif are encoded in strain ZY05719. Two novel LPxTG proteins SspB and YzpA were verified to be exported via a putative transport system that was dependent on the YSIRK-G/S directed translocation, and portrayed vital functions during the infection of SS2 strain ZY05719. Instead of exhibiting an inactivation of C5a peptidase in SspB, another LPxTG protein with an N-terminal YSIRK-G/S motif from Streptococcus agalactiae was depicted to cleave the C5a component of the host complement. The consequent domain-architecture retrieval determined more than 10,000 SspB/YzpA like proteins that are extensively distributed in the Gram-positive bacteria, and most of them harbor diverse glycosyl hydrolase or peptidase domains within their middle regions, thus presenting their capability to interact with host cells. The said findings provide compelling evidence that LPxTG proteins with an N-terminal YSIRK-G/S motif are polymorphic effectors secreted by Gram-positive bacteria, which can be further proposed to define as cell wall anchoring effectors in a new subset.
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Affiliation(s)
- Qiankun Bai
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Jiale Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Ze Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Xiaojun Zhong
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Zihao Pan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Yinchu Zhu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Yue Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Zongfu Wu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Guangjin Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Huochun Yao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
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19
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Halladin DK, Ortega FE, Ng KM, Footer MJ, Mitić NS, Malkov SN, Gopinathan A, Huang KC, Theriot JA. Entropy-driven translocation of disordered proteins through the Gram-positive bacterial cell wall. Nat Microbiol 2021; 6:1055-1065. [PMID: 34326523 DOI: 10.1038/s41564-021-00942-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 06/28/2021] [Indexed: 02/07/2023]
Abstract
In Gram-positive bacteria, a thick cross-linked cell wall separates the membrane from the extracellular space. Some surface-exposed proteins, such as the Listeria monocytogenes actin nucleation-promoting factor ActA, remain associated with the bacterial membrane but somehow thread through tens of nanometres of cell wall to expose their amino terminus to the exterior. Here, we report that entropy enables the translocation of disordered transmembrane proteins through the Gram-positive cell wall. We build a physical model, which predicts that the entropic constraint imposed by a thin periplasm is sufficient to drive the translocation of an intrinsically disordered protein such as ActA across a porous barrier similar to a peptidoglycan cell wall. We experimentally validate our model and show that ActA translocation depends on the cell-envelope dimensions and disordered-protein length, and that translocation is reversible. We also show that disordered regions of eukaryotic proteins can translocate Gram-positive cell walls via entropy. We propose that entropic forces are sufficient to drive the translocation of specific proteins to the outer surface.
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Affiliation(s)
- David K Halladin
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Biochemistry and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Fabian E Ortega
- Department of Biochemistry and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Katharine M Ng
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Matthew J Footer
- Department of Biochemistry and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA.,Department of Biology and Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Nenad S Mitić
- Faculty of Mathematics, University of Belgrade, Belgrade, Serbia
| | - Saša N Malkov
- Faculty of Mathematics, University of Belgrade, Belgrade, Serbia
| | - Ajay Gopinathan
- Department of Physics, University of California, Merced, CA, USA
| | - Kerwyn Casey Huang
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA. .,Department of Bioengineering, Stanford University, Stanford, CA, USA. .,Chan Zuckerberg Biohub, San Francisco, CA, USA.
| | - Julie A Theriot
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA. .,Department of Biochemistry and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA. .,Department of Biology and Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA.
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20
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Scaffidi SJ, Shebes MA, Yu W. Tracking the Subcellular Localization of Surface Proteins in Staphylococcus aureus by Immunofluorescence Microscopy. Bio Protoc 2021; 11:e4038. [PMID: 34150940 DOI: 10.21769/bioprotoc.4038] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/03/2021] [Accepted: 04/27/2021] [Indexed: 11/02/2022] Open
Abstract
Surface proteins of Staphylococcus aureus and other Gram-positive bacteria play essential roles in bacterial colonization and host-microbe interactions. Surface protein precursors containing a YSIRK/GXXS signal peptide are translocated across the septal membrane at mid-cell, anchored to the cell wall peptidoglycan at the cross-wall compartment, and presented on the new hemispheres of the daughter cells following cell division. After several generations of cell division, these surface proteins will eventually cover the entire cell surface. To understand how these proteins travel from the bacterial cytoplasm to the cell surface, we describe a series of immunofluorescence microscopy protocols designed to detect the stepwise subcellular localization of the surface protein precursors: surface display (protocol A), cross-wall localization (protocol B), and cytoplasmic/septal membrane localization (protocol C). Staphylococcal protein A (SpA) is the model protein used in this work. The protocols described here are readily adapted to study the localization of other surface proteins as well as other cytoplasmic or membrane proteins in S. aureus in general. Furthermore, the protocols can be modified and adapted for use in other Gram-positive bacteria. Graphic abstract: Tracking the subcellular localization of surface proteins in S. aureus.
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Affiliation(s)
- Salvatore J Scaffidi
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Mac A Shebes
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Wenqi Yu
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, USA
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21
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Zhang R, Shebes MA, Kho K, Scaffidi SJ, Meredith TC, Yu W. Spatial regulation of protein A in Staphylococcus aureus. Mol Microbiol 2021; 116:589-605. [PMID: 33949015 DOI: 10.1111/mmi.14734] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 12/31/2022]
Abstract
Surface proteins of Staphylococcus aureus play vital roles in bacterial physiology and pathogenesis. Recent work suggests that surface proteins are spatially regulated by a YSIRK/GXXS signal peptide that promotes cross-wall targeting at the mid-cell, though the mechanisms remain unclear. We previously showed that protein A (SpA), a YSIRK/GXXS protein and key staphylococcal virulence factor, mis-localizes in a ltaS mutant deficient in lipoteichoic acid (LTA) production. Here, we identified that SpA contains another cross-wall targeting signal, the LysM domain, which, in addition to the YSIRK/GXXS signal peptide, significantly enhances SpA cross-wall targeting. We show that LTA synthesis, but not LtaS, is required for SpA septal anchoring and cross-wall deposition. Interestingly, LTA is predominantly found at the peripheral cell membrane and is diminished at the septum of dividing staphylococcal cells, suggesting a restriction mechanism for SpA septal localization. Finally, we show that D-alanylation of LTA abolishes SpA cross-wall deposition by disrupting SpA distribution in the peptidoglycan layer without altering SpA septal anchoring. Our study reveals that multiple factors contribute to the spatial regulation and cross-wall targeting of SpA via different mechanisms, which coordinately ensures efficient incorporation of surface proteins into the growing peptidoglycan during the cell cycle.
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Affiliation(s)
- Ran Zhang
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
| | - Mac A Shebes
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
| | - Kelvin Kho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Salvatore J Scaffidi
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
| | - Timothy C Meredith
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Wenqi Yu
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
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22
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Chaudhary R, Mishra S, Kota S, Misra H. Molecular interactions and their predictive roles in cell pole determination in bacteria. Crit Rev Microbiol 2021; 47:141-161. [PMID: 33423591 DOI: 10.1080/1040841x.2020.1857686] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Bacterial cell cycle is divided into well-coordinated phases; chromosome duplication and segregation, cell elongation, septum formation, and cytokinesis. The temporal separation of these phases depends upon the growth rates and doubling time in different bacteria. The entire process of cell division starts with the assembly of divisome complex at mid-cell position followed by constriction of the cell wall and septum formation. In the mapping of mid-cell position for septum formation, the gradient of oscillating Min proteins across the poles plays a pivotal role in several bacteria genus. The cues in the cell that defines the poles and plane of cell division are not fully characterized in cocci. Recent studies have shed some lights on molecular interactions at the poles and the underlying mechanisms involved in pole determination in non-cocci. In this review, we have brought forth recent findings on these aspects together, which would suggest a model to explain the mechanisms of pole determination in rod shaped bacteria and could be extrapolated as a working model in cocci.
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Affiliation(s)
- Reema Chaudhary
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India.,Life Sciences, Homi Bhabha National Institute, Mumbai, India
| | - Shruti Mishra
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India.,Life Sciences, Homi Bhabha National Institute, Mumbai, India
| | - Swathi Kota
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India.,Life Sciences, Homi Bhabha National Institute, Mumbai, India
| | - Hari Misra
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India.,Life Sciences, Homi Bhabha National Institute, Mumbai, India
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Ellis-Guardiola K, Mahoney BJ, Clubb RT. NEAr Transporter (NEAT) Domains: Unique Surface Displayed Heme Chaperones That Enable Gram-Positive Bacteria to Capture Heme-Iron From Hemoglobin. Front Microbiol 2021; 11:607679. [PMID: 33488548 PMCID: PMC7815599 DOI: 10.3389/fmicb.2020.607679] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/03/2020] [Indexed: 11/13/2022] Open
Abstract
Iron is an important micronutrient that is required by bacteria to proliferate and to cause disease. Many bacterial pathogens forage iron from human hemoglobin (Hb) during infections, which contains this metal within heme (iron-protoporphyrin IX). Several clinically important pathogenic species within the Firmicutes phylum scavenge heme using surface-displayed or secreted NEAr Transporter (NEAT) domains. In this review, we discuss how these versatile proteins function in the Staphylococcus aureus Iron-regulated surface determinant system that scavenges heme-iron from Hb. S. aureus NEAT domains function as either Hb receptors or as heme-binding chaperones. In vitro studies have shown that heme-binding NEAT domains can rapidly exchange heme amongst one another via transiently forming transfer complexes, leading to the interesting hypothesis that they may form a protein-wire within the peptidoglycan layer through which heme flows from the microbial surface to the membrane. In Hb receptors, recent studies have revealed how dedicated heme- and Hb-binding NEAT domains function synergistically to extract Hb's heme molecules, and how receptor binding to the Hb-haptoglobin complex may block its clearance by macrophages, prolonging microbial access to Hb's iron. The functions of NEAT domains in other Gram-positive bacteria are also reviewed.
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Affiliation(s)
- Ken Ellis-Guardiola
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA, United States
| | - Brendan J. Mahoney
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA, United States
| | - Robert T. Clubb
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA, United States
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
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Valle J, Fang X, Lasa I. Revisiting Bap Multidomain Protein: More Than Sticking Bacteria Together. Front Microbiol 2020; 11:613581. [PMID: 33424817 PMCID: PMC7785521 DOI: 10.3389/fmicb.2020.613581] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/03/2020] [Indexed: 12/21/2022] Open
Abstract
One of the major components of the staphylococcal biofilm is surface proteins that assemble as scaffold components of the biofilm matrix. Among the different surface proteins able to contribute to biofilm formation, this review is dedicated to the Biofilm Associated Protein (Bap). Bap is part of the accessory genome of Staphylococcus aureus but orthologs of Bap in other staphylococcal species belong to the core genome. When present, Bap promotes adhesion to abiotic surfaces and induces strong intercellular adhesion by self-assembling into amyloid like aggregates in response to the levels of calcium and the pH in the environment. During infection, Bap enhances the adhesion to epithelial cells where it binds directly to the host receptor Gp96 and inhibits the entry of the bacteria into the cells. To perform such diverse range of functions, Bap comprises several domains, and some of them include several motifs associated to distinct functions. Based on the knowledge accumulated with the Bap protein of S. aureus, this review aims to summarize the current knowledge of the structure and properties of each domain of Bap and their contribution to Bap functionality.
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Affiliation(s)
- Jaione Valle
- Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, Mutilva, Spain
| | - Xianyang Fang
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Iñigo Lasa
- Laboratory of Microbial Pathogenesis, Navarrabiomed-Universidad Pública de Navarra-Departamento de Salud, IDISNA, Pamplona, Spain
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Thappeta KRV, Zhao LN, Nge CE, Crasta S, Leong CY, Ng V, Kanagasundaram Y, Fan H, Ng SB. In-Silico Identified New Natural Sortase A Inhibitors Disrupt S. aureus Biofilm Formation. Int J Mol Sci 2020; 21:ijms21228601. [PMID: 33202690 PMCID: PMC7696255 DOI: 10.3390/ijms21228601] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/09/2020] [Accepted: 11/12/2020] [Indexed: 12/12/2022] Open
Abstract
Sortase A (SrtA) is a membrane-associated enzyme that anchors surface-exposed proteins to the cell wall envelope of Gram-positive bacteria such as Staphylococcus aureus. As SrtA is essential for Gram-positive bacterial pathogenesis but dispensable for microbial growth or viability, SrtA is considered a favorable target for the enhancement of novel anti-infective drugs that aim to interfere with key bacterial virulence mechanisms, such as biofilm formation, without developing drug resistance. Here, we used virtual screening to search an in-house natural compound library and identified two natural compounds, N1287 (Skyrin) and N2576 ((4,5-dichloro-1H-pyrrol-2-yl)-[2,4-dihydroxy-3-(4-methyl-pentyl)-phenyl]-methanone) that inhibited the enzymatic activity of SrtA. These compounds also significantly reduced the growth of S. aureus but possessed moderate mammalian toxicity. Furthermore, S. aureus strains treated with these compounds exhibited reduction in adherence to host fibrinogen, as well as biofilm formation. Hence, these compounds may represent an anti-infective therapy without the side effects of antibiotics.
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Affiliation(s)
- Kishore Reddy Venkata Thappeta
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #01-02 Nanos, Singapore 138669, Singapore; (K.R.V.T.); (C.E.N.); (S.C.); (C.Y.L.); (V.N.)
| | - Li Na Zhao
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore;
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, #3-09 Proteos, Singapore 138673, Singapore
| | - Choy Eng Nge
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #01-02 Nanos, Singapore 138669, Singapore; (K.R.V.T.); (C.E.N.); (S.C.); (C.Y.L.); (V.N.)
| | - Sharon Crasta
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #01-02 Nanos, Singapore 138669, Singapore; (K.R.V.T.); (C.E.N.); (S.C.); (C.Y.L.); (V.N.)
| | - Chung Yan Leong
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #01-02 Nanos, Singapore 138669, Singapore; (K.R.V.T.); (C.E.N.); (S.C.); (C.Y.L.); (V.N.)
| | - Veronica Ng
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #01-02 Nanos, Singapore 138669, Singapore; (K.R.V.T.); (C.E.N.); (S.C.); (C.Y.L.); (V.N.)
| | - Yoganathan Kanagasundaram
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #01-02 Nanos, Singapore 138669, Singapore; (K.R.V.T.); (C.E.N.); (S.C.); (C.Y.L.); (V.N.)
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore;
- Correspondence: (Y.K.); (H.F.); (S.B.N.); Tel.: +65-6586-9508 (Y.K.); +65-6478-8500 (H.F.); +65-6478-8513 (S.B.N.)
| | - Hao Fan
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore;
- Correspondence: (Y.K.); (H.F.); (S.B.N.); Tel.: +65-6586-9508 (Y.K.); +65-6478-8500 (H.F.); +65-6478-8513 (S.B.N.)
| | - Siew Bee Ng
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #01-02 Nanos, Singapore 138669, Singapore; (K.R.V.T.); (C.E.N.); (S.C.); (C.Y.L.); (V.N.)
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore;
- Correspondence: (Y.K.); (H.F.); (S.B.N.); Tel.: +65-6586-9508 (Y.K.); +65-6478-8500 (H.F.); +65-6478-8513 (S.B.N.)
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Liesenborghs L, Meyers S, Lox M, Criel M, Claes J, Peetermans M, Trenson S, Vande Velde G, Vanden Berghe P, Baatsen P, Missiakas D, Schneewind O, Peetermans WE, Hoylaerts MF, Vanassche T, Verhamme P. Staphylococcus aureus endocarditis: distinct mechanisms of bacterial adhesion to damaged and inflamed heart valves. Eur Heart J 2020; 40:3248-3259. [PMID: 30945735 DOI: 10.1093/eurheartj/ehz175] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 02/03/2019] [Accepted: 03/12/2019] [Indexed: 11/12/2022] Open
Abstract
AIMS The pathogenesis of endocarditis is not well understood resulting in unsuccessful attempts at prevention. Clinical observations suggest that Staphylococcus aureus infects either damaged or inflamed heart valves. Using a newly developed endocarditis mouse model, we therefore studied the initial adhesion of S. aureus in both risk states. METHODS AND RESULTS Using 3D confocal microscopy, we examined the adhesion of fluorescent S. aureus to murine aortic valves. To mimic different risk states we either damaged the valves with a surgically placed catheter or simulated valve inflammation by local endothelium activation. We used von Willebrand factor (VWF) gene-deficient mice, induced platelet and fibrinogen depletion and used several S. aureus mutant strains to investigate the contribution of both host and bacterial factors in early bacterial adhesion. Both cardiac valve damage and inflammation predisposed to endocarditis, but by distinct mechanisms. Following valve damage, S. aureus adhered directly to VWF and fibrin, deposited on the damaged valve. This was mediated by Sortase A-dependent adhesins such as VWF-binding protein and Clumping factor A. Platelets did not contribute. In contrast, upon cardiac valve inflammation, widespread endothelial activation led to endothelial cell-bound VWF release. This recruited large amounts of platelets, capturing S. aureus to the valve surface. Here, neither fibrinogen, nor Sortase A were essential. CONCLUSION Cardiac valve damage and inflammation predispose to S. aureus endocarditis via distinct mechanisms. These findings may have important implications for the development of new preventive strategies, as some interventions might be effective in one risk state, but not in the other.
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Affiliation(s)
- Laurens Liesenborghs
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Herestraat 49, Leuven, Belgium
| | - Severien Meyers
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Herestraat 49, Leuven, Belgium
| | - Marleen Lox
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Herestraat 49, Leuven, Belgium
| | - Maarten Criel
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Herestraat 49, Leuven, Belgium
| | - Jorien Claes
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Herestraat 49, Leuven, Belgium
| | - Marijke Peetermans
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Herestraat 49, Leuven, Belgium
| | - Sander Trenson
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Herestraat 49, Leuven, Belgium
| | - Greetje Vande Velde
- Department of Imaging & Pathology, Biomedical MRI/Molecular Small Animal Imaging Center, KU Leuven, Leuven, Belgium
| | - Pieter Vanden Berghe
- Department of Chronic Diseases, Metabolism and Ageing, Lab for Enteric NeuroScience, TARGID, KU Leuven, Leuven, Belgium
| | - Pieter Baatsen
- VIB Bio Imaging Core and VIB-KU Leuven, Center for Brain and Disease Research, KU Leuven, Leuven, Belgium
| | | | - Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | | | - Marc F Hoylaerts
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Herestraat 49, Leuven, Belgium
| | - Thomas Vanassche
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Herestraat 49, Leuven, Belgium
| | - Peter Verhamme
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Herestraat 49, Leuven, Belgium
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27
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Willing S, Dyer E, Schneewind O, Missiakas D. FmhA and FmhC of Staphylococcus aureus incorporate serine residues into peptidoglycan cross-bridges. J Biol Chem 2020; 295:13664-13676. [PMID: 32759309 PMCID: PMC7521636 DOI: 10.1074/jbc.ra120.014371] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/03/2020] [Indexed: 12/16/2022] Open
Abstract
Staphylococcal peptidoglycan is characterized by pentaglycine cross-bridges that are cross-linked between adjacent wall peptides by penicillin-binding proteins to confer robustness and flexibility. In Staphylococcus aureus, pentaglycine cross-bridges are synthesized by three proteins: FemX adds the first glycine, and the homodimers FemA and FemB sequentially add two Gly-Gly dipeptides. Occasionally, serine residues are also incorporated into the cross-bridges by enzymes that have heretofore not been identified. Here, we show that the FemA/FemB homologues FmhA and FmhC pair with FemA and FemB to incorporate Gly-Ser dipeptides into cross-bridges and to confer resistance to lysostaphin, a secreted bacteriocin that cleaves the pentaglycine cross-bridge. FmhA incorporates serine residues at positions 3 and 5 of the cross-bridge. In contrast, FmhC incorporates a single serine at position 5. Serine incorporation also lowers resistance toward oxacillin, an antibiotic that targets penicillin-binding proteins, in both methicillin-sensitive and methicillin-resistant strains of S. aureus FmhC is encoded by a gene immediately adjacent to lytN, which specifies a hydrolase that cleaves the bond between the fifth glycine of cross-bridges and the alanine of the adjacent stem peptide. In this manner, LytN facilitates the separation of daughter cells. Cell wall damage induced upon lytN overexpression can be alleviated by overexpression of fmhC. Together, these observations suggest that FmhA and FmhC generate peptidoglycan cross-bridges with unique serine patterns that provide protection from endogenous murein hydrolases governing cell division and from bacteriocins produced by microbial competitors.
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Affiliation(s)
- Stephanie Willing
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Emma Dyer
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Dominique Missiakas
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA; Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA.
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28
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Wolden R, Pain M, Karlsson R, Karlsson A, Aarag Fredheim EG, Cavanagh JP. Identification of surface proteins in a clinical Staphylococcus haemolyticus isolate by bacterial surface shaving. BMC Microbiol 2020; 20:80. [PMID: 32264835 PMCID: PMC7137321 DOI: 10.1186/s12866-020-01778-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 03/31/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The skin commensal Staphylococcus haemolyticus is an emerging nosocomial pathogen. Despite its clinical relevance, published information about S. haemolyticus virulence factors is scarce. In this study, the adhesive and biofilm forming properties of ten clinical and ten commensal S. haemolyticus strains were examined using standard adhesion and biofilm assays. One of the clinical strains was used to identify expressed surface proteins using bacterial surface shaving. Protein abundance was examined by a comparative analysis between bacterial protein expression after human keratinocyte (HaCaT) colonization and growth in cell culture media supplemented with serum. Relative protein quantification was performed by labeling peptides with tandem mass tags (TMT) prior to Mass Spectrometry analysis. Surface proteins can be used as novel targets for antimicrobial treatment and in diagnostics. RESULTS Adherence to fibronectin, collagen and plastic was low in all tested strains, but with significantly higher adhesion to fibronectin (p = 0.041) and collagen (p = 0.001) in the commensal strains. There was a trend towards higher degree of biofilm formation in the clinical strains (p = 0.059). By using surface shaving, 325 proteins were detected, of which 65 were classified as surface proteins. Analyses showed that the abundance of nineteen (5.8%) proteins were significantly changed following HaCaT colonization. The bacterial Toll/interleukin-1 like (TIRs) domain containing protein (p = 0.04), the transglycosylase SceD (p = 0.01), and the bifunctional autolysin Atl (p = 0.04) showed a 1.4, 1.6- and 1.5-fold increased abundance. The staphylococcal secretory antigen (SsaA) (p = 0.04) was significantly downregulated (- 1.5 fold change) following HaCaT colonization. Among the 65 surface proteins the elastin binding protein (Ebps), LPXAG and LPXSG domain containing proteins and five LPXTG domain containing proteins were identified; three Sdr-like proteins, the extracellular matrix binding protein Embp and a SasH-like protein. CONCLUSIONS This study has provided novel knowledge about expression of S. haemolyticus surface proteins after direct contact with eukaryotic cells and in media supplemented with serum. We have identified surface proteins and immune evasive proteins previously only functionally described in other staphylococcal species. The identification of expressed proteins after host-microbe interaction offers a tool for the discovery and design of novel targets for antimicrobial treatment.
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Affiliation(s)
- Runa Wolden
- Pediatric Research group, Department of Clinical Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Maria Pain
- Pediatric Research group, Department of Clinical Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Roger Karlsson
- Nanoxis Consulting AB, Gothenburg, Sweden
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Clinical Microbiology, Sahlgrenska University Hospital, SE-413 46, Gothenburg, Region Västra Götaland, Sweden
| | | | - Elizabeth G Aarag Fredheim
- Microbial Pharmacology and Population Biology, Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Jorunn Pauline Cavanagh
- Pediatric Research group, Department of Clinical Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.
- Department of Pediatrics, The University Hospital of North Norway, Tromsø, Norway.
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Schneewind O, Missiakas DM. Staphylococcal Protein Secretion and Envelope Assembly. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0070-2019. [PMID: 31267890 PMCID: PMC7028390 DOI: 10.1128/microbiolspec.gpp3-0070-2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Indexed: 12/13/2022] Open
Abstract
The highly cross-linked peptidoglycan represents the rigid layer of the bacterial envelope and protects bacteria from osmotic lysis. In Gram-positive bacteria, peptidoglycan also functions as a scaffold for the immobilization of capsular polysaccharide, wall teichoic acid (WTA), and surface proteins. This chapter captures recent development on the assembly of the envelope of Staphylococcus aureus including mechanisms accounting for immobilization of molecules to peptidoglycan as well as hydrolysis of peptidoglycan for the specific release of bound molecules, facilitation of protein secretion across the envelope and cell division. Peptidoglycan, WTA and capsular polysaccharide are directly synthesized onto undecaprenol. Surface proteins are anchored by Sortase A, a membrane-embedded transpeptidase that scans secreted polypeptides for the C-terminal LPXTG motif of sorting signals. The resulting acyl enzyme intermediate is resolved by lipid II, the undecaprenol-bound peptidoglycan precursor. While these pathways share membrane diffusible undecaprenol, assembly of these molecules occurs either at the cross-walls or the cell poles. In S. aureus, the cross-wall represents the site of de novo peptidoglycan synthesis which is eventually split to complete the cell cycle yielding newly divided daughter cells. Peptidoglycan synthesized at the cross-wall is initially devoid of WTA. Conversely, lipoteichoic acid (LTA) synthesis which does not require bactoprenol is seemingly restricted to septal membranes. Similarly, S. aureus distinguishes two types of surface protein precursors. Polypeptides with canonical signal peptides are deposited at the cell poles, whereas precursors with conserved YSIRK-GXXS motif signal peptides traffic to the cross-wall. A model for protein trafficking in the envelope and uneven distribution of teichoic acids is discussed.
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Affiliation(s)
- Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, IL 60637
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Schneewind O, Missiakas D. Sortases, Surface Proteins, and Their Roles in Staphylococcus aureus Disease and Vaccine Development. Microbiol Spectr 2019; 7:10.1128/microbiolspec.PSIB-0004-2018. [PMID: 30737913 PMCID: PMC6386163 DOI: 10.1128/microbiolspec.psib-0004-2018] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Indexed: 12/27/2022] Open
Abstract
Sortases cleave short peptide motif sequences at the C-terminal end of secreted surface protein precursors and either attach these polypeptides to the peptidoglycan of Gram-positive bacteria or promote their assembly into pilus structures that are also attached to peptidoglycan. Sortase A, the enzyme first identified in the human pathogen Staphylococcus aureus, binds LPXTG motif sorting signals, cleaves between threonine (T) and glycine (G) residues, and forms an acyl enzyme between its active-site cysteine thiol and the carboxyl group of threonine (T). Sortase A acyl enzyme is relieved by the nucleophilic attack of the cross bridge amino group within lipid II, thereby generating surface protein linked to peptidoglycan precursor. Such products are subsequently incorporated into the cell wall envelope by enzymes of the peptidoglycan synthesis pathway. Surface proteins linked to peptidoglycan may be released from the bacterial envelope to diffuse into host tissues and fulfill specific biological functions. S. aureus sortase A is essential for host colonization and for the pathogenesis of invasive diseases. Staphylococcal sortase-anchored surface proteins fulfill key functions during the infectious process, and vaccine-induced antibodies targeting surface proteins may provide protection against S. aureus. Alternatively, small-molecule inhibitors of sortase may be useful agents for the prevention of S. aureus colonization and invasive disease.
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Affiliation(s)
- Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, IL 60637
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31
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Yu W, Missiakas D, Schneewind O. Septal secretion of protein A in Staphylococcus aureus requires SecA and lipoteichoic acid synthesis. eLife 2018; 7:34092. [PMID: 29757141 PMCID: PMC5962339 DOI: 10.7554/elife.34092] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 05/05/2018] [Indexed: 12/26/2022] Open
Abstract
Surface proteins of Staphylococcus aureus are secreted across septal membranes for assembly into the bacterial cross-wall. This localized secretion requires the YSIRK/GXXS motif signal peptide, however the mechanisms supporting precursor trafficking are not known. We show here that the signal peptide of staphylococcal protein A (SpA) is cleaved at the YSIRK/GXXS motif. A SpA signal peptide mutant defective for YSIRK/GXXS cleavage is also impaired for septal secretion and co-purifies with SecA, SecDF and LtaS. SecA depletion blocks precursor targeting to septal membranes, whereas deletion of secDF diminishes SpA secretion into the cross-wall. Depletion of LtaS blocks lipoteichoic acid synthesis and abolishes SpA precursor trafficking to septal membranes. We propose a model whereby SecA directs SpA precursors to lipoteichoic acid-rich septal membranes for YSIRK/GXXS motif cleavage and secretion into the cross-wall.
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Affiliation(s)
- Wenqi Yu
- Department of Microbiology, University of Chicago, Chicago, United States
| | | | - Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, United States
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32
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Ajayi C, Åberg E, Askarian F, Sollid JUE, Johannessen M, Hanssen AM. Genetic variability in the sdrD gene in Staphylococcus aureus from healthy nasal carriers. BMC Microbiol 2018; 18:34. [PMID: 29661152 PMCID: PMC5902956 DOI: 10.1186/s12866-018-1179-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 04/08/2018] [Indexed: 11/26/2022] Open
Abstract
Background Staphylococcus aureus cell wall anchored Serine Aspartate repeat containing protein D (SdrD) is a member of the microbial surface component recognising adhesive matrix molecules (MSCRAMMs). It is involved in the bacterial adhesion and virulence. However the extent of genetic variation in S. aureus sdrD gene within isolates from healthy carriers are not known. The aim of this study was to evaluate allelic variation of the sdrD gene among S. aureus from healthy nasal carriers. Results The sdrD A region from 48 S. aureus isolates from healthy carriers were analysed and classified into seven variants. Variations in the sdrD A region were concentrated in the N2 and N3 subdomains. Sequence analysis of the entire sdrD gene of representative isolates revealed variations in the SD repeat and the EF motifs of the B repeat. In silico structural modelling indicates that there are no differences in the SdrD structure of the 7 variants. Variable amino acid residues mapped onto the 3D structure revealed that the variations are surface located, exist within the groove between the N2-N3 subdomains and distributed mainly on the N3 subdomain. Comparison of adhesion to keratinocytes in an in vitro cell adhesion assay, using NCTC 8325–4∆sdrD strains expressing the various sdrD gene variants, indicated a significant difference between only two complements while others showed no major difference in their adhesion. Conclusions This study provides evidence of sequence variations across the different domains of SdrD from S. aureus isolated from healthy nasal carriers. Proper understanding of these variations is necessary in the study of S. aureus pathogenesis. Electronic supplementary material The online version of this article (10.1186/s12866-018-1179-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Clement Ajayi
- Research group of Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037, Tromsø, Norway.
| | - Espen Åberg
- Research group of Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037, Tromsø, Norway
| | - Fatemeh Askarian
- Research group of Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037, Tromsø, Norway
| | - Johanna U E Sollid
- Research group of Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037, Tromsø, Norway
| | - Mona Johannessen
- Research group of Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037, Tromsø, Norway
| | - Anne-Merethe Hanssen
- Research group of Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037, Tromsø, Norway.
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Carrera M, Böhme K, Gallardo JM, Barros-Velázquez J, Cañas B, Calo-Mata P. Characterization of Foodborne Strains of Staphylococcus aureus by Shotgun Proteomics: Functional Networks, Virulence Factors and Species-Specific Peptide Biomarkers. Front Microbiol 2017; 8:2458. [PMID: 29312172 PMCID: PMC5732212 DOI: 10.3389/fmicb.2017.02458] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/27/2017] [Indexed: 11/13/2022] Open
Abstract
In the present work, we applied a shotgun proteomics approach for the fast and easy characterization of 20 different foodborne strains of Staphylococcus aureus (S. aureus), one of the most recognized foodborne pathogenic bacteria. A total of 644 non-redundant proteins were identified and analyzed via an easy and rapid protein sample preparation procedure. The results allowed the differentiation of several proteome datasets from the different strains (common, accessory, and unique datasets), which were used to determine relevant functional pathways and differentiate the strains into different Euclidean hierarchical clusters. Moreover, a predicted protein-protein interaction network of the foodborne S. aureus strains was created. The whole confidence network contains 77 nodes and 769 interactions. Most of the identified proteins were surface-associated proteins that were related to pathways and networks of energy, lipid metabolism and virulence. Twenty-seven virulence factors were identified, and most of them corresponded to autolysins, N-acetylmuramoyl-L-alanine amidases, phenol-soluble modulins, extracellular fibrinogen-binding proteins and virulence factor EsxA. Potential species-specific peptide biomarkers were screened. Twenty-one species-specific peptide biomarkers, belonging to eight different proteins (nickel-ABC transporter, N-acetylmuramoyl-L-alanine amidase, autolysin, clumping factor A, gram-positive signal peptide YSIRK, cysteine protease/staphopain, transcriptional regulator MarR, and transcriptional regulator Sar-A), were proposed to identify S. aureus. These results constitute the first major dataset of peptides and proteins of foodborne S. aureus strains. This repository may be useful for further studies, for the development of new therapeutic treatments for S. aureus food intoxications and for microbial source-tracking in foodstuffs.
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Affiliation(s)
- Mónica Carrera
- Department of Food Technology, Spanish National Research Council, Marine Research Institute, Vigo, Spain
| | - Karola Böhme
- Department of Analytical Chemistry, Nutrition and Food Science, School of Veterinary Sciences, University of Santiago de Compostela, Lugo, Spain
| | - José M. Gallardo
- Department of Food Technology, Spanish National Research Council, Marine Research Institute, Vigo, Spain
| | - Jorge Barros-Velázquez
- Department of Analytical Chemistry, Nutrition and Food Science, School of Veterinary Sciences, University of Santiago de Compostela, Lugo, Spain
| | - Benito Cañas
- Department of Analytical Chemistry, Complutense University of Madrid, Madrid, Spain
| | - Pilar Calo-Mata
- Department of Analytical Chemistry, Nutrition and Food Science, School of Veterinary Sciences, University of Santiago de Compostela, Lugo, Spain
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34
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Cavallari M. Rapid and Direct VHH and Target Identification by Staphylococcal Surface Display Libraries. Int J Mol Sci 2017; 18:ijms18071507. [PMID: 28704956 PMCID: PMC5535997 DOI: 10.3390/ijms18071507] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 07/07/2017] [Accepted: 07/10/2017] [Indexed: 01/01/2023] Open
Abstract
Unbiased and simultaneous identification of a specific antibody and its target antigen has been difficult without prior knowledge of at least one interaction partner. Immunization with complex mixtures of antigens such as whole organisms and tissue extracts including tumoral ones evokes a highly diverse immune response. During such a response, antibodies are generated against a variety of epitopes in the mixture. Here, we propose a surface display design that is suited to simultaneously identify camelid single domain antibodies and their targets. Immune libraries of single-domain antigen recognition fragments from camelid heavy chain-only antibodies (VHH) were attached to the peptidoglycan of Gram-positive Staphylococcus aureus employing its endogenous housekeeping sortase enzyme. The sortase transpeptidation reaction covalently attached the VHH to the bacterial peptidoglycan. The reversible nature of the reaction allowed the recovery of the VHH from the bacterial surface and the use of the VHH in downstream applications. These staphylococcal surface display libraries were used to rapidly identify VHH as well as their targets by immunoprecipitation (IP). Our novel bacterial surface display platform was stable under harsh screening conditions, allowed fast target identification, and readily permitted the recovery of the displayed VHH for downstream analysis.
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Affiliation(s)
- Marco Cavallari
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schaenzlestrasse 18, 79104 Freiburg, Germany.
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35
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Talens-Perales D, Górska A, Huson DH, Polaina J, Marín-Navarro J. Analysis of Domain Architecture and Phylogenetics of Family 2 Glycoside Hydrolases (GH2). PLoS One 2016; 11:e0168035. [PMID: 27930742 PMCID: PMC5145203 DOI: 10.1371/journal.pone.0168035] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 11/23/2016] [Indexed: 11/23/2022] Open
Abstract
In this work we report a detailed analysis of the topology and phylogenetics of family 2 glycoside hydrolases (GH2). We distinguish five topologies or domain architectures based on the presence and distribution of protein domains defined in Pfam and Interpro databases. All of them share a central TIM barrel (catalytic module) with two β-sandwich domains (non-catalytic) at the N-terminal end, but differ in the occurrence and nature of additional non-catalytic modules at the C-terminal region. Phylogenetic analysis was based on the sequence of the Pfam Glyco_hydro_2_C catalytic module present in most GH2 proteins. Our results led us to propose a model in which evolutionary diversity of GH2 enzymes is driven by the addition of different non-catalytic domains at the C-terminal region. This model accounts for the divergence of β-galactosidases from β-glucuronidases, the diversification of β-galactosidases with different transglycosylation specificities, and the emergence of bicistronic β-galactosidases. This study also allows the identification of groups of functionally uncharacterized protein sequences with potential biotechnological interest.
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Affiliation(s)
- David Talens-Perales
- Instituto de Agroquímica y Tecnología de Alimentos, CSIC, Paterna, Valencia, Spain
| | - Anna Górska
- Center for Bioinformatics, University of Tübingen, Tübingen, Germany
| | - Daniel H. Huson
- Center for Bioinformatics, University of Tübingen, Tübingen, Germany
| | - Julio Polaina
- Instituto de Agroquímica y Tecnología de Alimentos, CSIC, Paterna, Valencia, Spain
| | - Julia Marín-Navarro
- Instituto de Agroquímica y Tecnología de Alimentos, CSIC, Paterna, Valencia, Spain
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36
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Hymes JP, Klaenhammer TR. Stuck in the Middle: Fibronectin-Binding Proteins in Gram-Positive Bacteria. Front Microbiol 2016; 7:1504. [PMID: 27713740 PMCID: PMC5031765 DOI: 10.3389/fmicb.2016.01504] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/08/2016] [Indexed: 11/13/2022] Open
Abstract
Fibronectin is a multidomain glycoprotein found ubiquitously in human body fluids and extracellular matrices of a variety of cell types from all human tissues and organs, including intestinal epithelial cells. Fibronectin plays a major role in the regulation of cell migration, tissue repair, and cell adhesion. Importantly, fibronectin also serves as a common target for bacterial adhesins in the gastrointestinal tract. Fibronectin-binding proteins (FnBPs) have been identified and characterized in a wide variety of host-associated bacteria. Single bacterial species can contain multiple, diverse FnBPs. In pathogens, some FnBPs contribute to virulence via host cell attachment, invasion, and interference with signaling pathways. Although FnBPs in commensal and probiotic strains are not sufficient to confer virulence, they are essential for attachment to their ecological niches. Here we describe the interaction between human fibronectin and bacterial adhesins by highlighting the FnBPs of Gram-positive pathogens and commensals. We provide an overview of the occurrence and diversity of FnBPs with a focus on the model pathogenic organisms in which FnBPs are most characterized. Continued investigation of FnBPs is needed to fully understand their divergence and specificity in both pathogens and commensals.
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Affiliation(s)
- Jeffrey P Hymes
- Department of Food, Bioprocessing, and Nutrition Sciences, North Carolina State University Raleigh, NC, USA
| | - Todd R Klaenhammer
- Department of Food, Bioprocessing, and Nutrition Sciences, North Carolina State University Raleigh, NC, USA
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37
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Jensen H, Drømtorp SM, Axelsson L, Grimmer S. Immunomodulation of monocytes by probiotic and selected lactic Acid bacteria. Probiotics Antimicrob Proteins 2016; 7:14-23. [PMID: 25331988 DOI: 10.1007/s12602-014-9174-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Some lactic acid bacteria (LAB), especially bacteria belonging to the genus Lactobacillus, are recognized as common inhabitants of the human gastrointestinal tract and have received considerable attention in the last decades due to their postulated health-promoting effects. LAB and probiotic bacteria can modulate the host immune response. However, much is unknown about the mediators and mechanisms responsible for their immunological effect. Here, we present a study using cytokine secretion from the monocytic cell line THP-1 and NF-κB activation in the monocytic cell line U937-3xkB-LUC to elucidate immune stimulating abilities of LAB in vitro. In this study, we investigate both commercially available and potential probiotic LAB strains, and the role of putative surface proteins of L. reuteri using mutants. L. reuteri strains induced the highest cytokine secretion and the highest NF-κB activation, whereas L. plantarum strains and L. rhamnosus GG were low inducers/activators. One of the putative L. reuteri surface proteins, Hmpref0536_10802, appeared to be of importance for the stimulation of THP-1 cells and the activation of NF-κB in U937-3xkB-LUC cells. Live and UV-inactivated preparations resulted in different responses for two of the strains investigated. Our results add to the complexity in the interaction between LAB and human cells and suggest the possible involvement of secreted pro- and anti-inflammatory mediators of LAB. It is likely that it is the sum of bacterial surface proteins and bacterial metabolites and/or secreted proteins that induce cytokine secretion in THP-1 cells and activate NF-κB in U937-3xkB-LUC cells in this study.
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Affiliation(s)
- Hanne Jensen
- Nofima, Norwegian Institute of Food, Fisheries, and Aquaculture Research, P.O. Box 210, 1431, Ås, Norway,
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38
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Mitra SD, Afonina I, Kline KA. Right Place, Right Time: Focalization of Membrane Proteins in Gram-Positive Bacteria. Trends Microbiol 2016; 24:611-621. [PMID: 27117048 DOI: 10.1016/j.tim.2016.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 03/03/2016] [Accepted: 03/24/2016] [Indexed: 11/25/2022]
Abstract
Membrane proteins represent a significant proportion of total bacterial proteins and perform vital cellular functions ranging from exchanging metabolites and genetic material, secretion and sorting, sensing signal molecules, and cell division. Many of these functions are carried out at distinct foci on the bacterial membrane, and this subcellular localization can be coordinated by a number of factors, including lipid microdomains, protein-protein interactions, and membrane curvature. Elucidating the mechanisms behind focal protein localization in bacteria informs not only protein structure-function correlation, but also how to disrupt the protein function to limit virulence. Here we review recent advances describing a functional role for subcellular localization of membrane proteins involved in genetic transfer, secretion and sorting, cell division and growth, and signaling.
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Affiliation(s)
- Sumitra D Mitra
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Irina Afonina
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore.
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39
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Douillard FP, Rasinkangas P, Bhattacharjee A, Palva A, de Vos WM. The N-Terminal GYPSY Motif Is Required for Pilin-Specific Sortase SrtC1 Functionality in Lactobacillus rhamnosus Strain GG. PLoS One 2016; 11:e0153373. [PMID: 27070897 PMCID: PMC4829219 DOI: 10.1371/journal.pone.0153373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 03/29/2016] [Indexed: 12/31/2022] Open
Abstract
Predominantly identified in pathogenic Gram-positive bacteria, sortase-dependent pili are also found in commensal species, such as the probiotic-marketed strain Lactobacillus rhamnosus strain GG. Pili are typically associated with host colonization, immune signalling and biofilm formation. Comparative analysis of the N-terminal domains of pilin-specific sortases from various piliated Gram-positive bacteria identified a conserved motif, called GYPSY, within the signal sequence. We investigated the function and role of the GYPSY residues by directed mutagenesis in homologous (rod-shaped) and heterologous (coccoid-shaped) expression systems for pilus formation. Substitutions of some of the GYPSY residues, and more specifically the proline residue, were found to have a direct impact on the degree of piliation of Lb. rhamnosus GG. The present findings uncover a new signalling element involved in the functionality of pilin-specific sortases controlling the pilus biogenesis of Lb. rhamnosus GG and related piliated Gram-positive species.
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Affiliation(s)
- François P. Douillard
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
- * E-mail: (FPD); (WMdV)
| | - Pia Rasinkangas
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Arnab Bhattacharjee
- Research Programs Unit Immunobiology, Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | - Airi Palva
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Willem M. de Vos
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
- Research Programs Unit Immunobiology, Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
- * E-mail: (FPD); (WMdV)
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40
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Spatial Organization of Cell Wall-Anchored Proteins at the Surface of Gram-Positive Bacteria. Curr Top Microbiol Immunol 2016; 404:177-201. [DOI: 10.1007/82_2016_4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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41
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Raz A, Tanasescu AM, Zhao AM, Serrano A, Alston T, Sol A, Bachrach G, Fischetti VA. Streptococcus pyogenes Sortase Mutants Are Highly Susceptible to Killing by Host Factors Due to Aberrant Envelope Physiology. PLoS One 2015; 10:e0140784. [PMID: 26484774 PMCID: PMC4617865 DOI: 10.1371/journal.pone.0140784] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 09/30/2015] [Indexed: 12/31/2022] Open
Abstract
Cell wall anchored virulence factors are critical for infection and colonization of the host by Gram-positive bacteria. Such proteins have an N-terminal leader sequence and a C-terminal sorting signal, composed of an LPXTG motif, a hydrophobic stretch, and a few positively charged amino acids. The sorting signal halts translocation across the membrane, allowing sortase to cleave the LPXTG motif, leading to surface anchoring. Deletion of sortase prevents the anchoring of virulence factors to the wall; the effects on bacterial physiology however, have not been thoroughly characterized. Here we show that deletion of Streptococcus pyogenes sortase A leads to accumulation of sorting intermediates, particularly at the septum, altering cellular morphology and physiology, and compromising membrane integrity. Such cells are highly sensitive to cathelicidin, and are rapidly killed in blood and plasma. These phenomena are not a loss-of-function effect caused by the absence of anchored surface proteins, but specifically result from the accumulation of sorting intermediates. Reduction in the level of sorting intermediates leads to a return of the sortase mutant to normal morphology, while expression of M protein with an altered LPXTG motif in wild type cells leads to toxicity in the host environment, similar to that observed in the sortase mutant. These unanticipated effects suggest that inhibition of sortase by small-molecule inhibitors could similarly lead to the rapid elimination of pathogens from an infected host, making such inhibitors much better anti-bacterial agents than previously believed.
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Affiliation(s)
- Assaf Raz
- Bacterial Pathogenesis and Immunology, The Rockefeller University, 1230 York Avenue Box 172, New York, New York, 10065, United States of America
| | - Ana-Maria Tanasescu
- Bacterial Pathogenesis and Immunology, The Rockefeller University, 1230 York Avenue Box 172, New York, New York, 10065, United States of America
| | - Anna M. Zhao
- Bacterial Pathogenesis and Immunology, The Rockefeller University, 1230 York Avenue Box 172, New York, New York, 10065, United States of America
| | - Anna Serrano
- Bacterial Pathogenesis and Immunology, The Rockefeller University, 1230 York Avenue Box 172, New York, New York, 10065, United States of America
| | - Tricia Alston
- Bacterial Pathogenesis and Immunology, The Rockefeller University, 1230 York Avenue Box 172, New York, New York, 10065, United States of America
| | - Asaf Sol
- Institute of Dental Sciences, Hebrew University - Hadassah School of Dental Medicine, Jerusalem 91120, Israel
| | - Gilad Bachrach
- Institute of Dental Sciences, Hebrew University - Hadassah School of Dental Medicine, Jerusalem 91120, Israel
| | - Vincent A. Fischetti
- Bacterial Pathogenesis and Immunology, The Rockefeller University, 1230 York Avenue Box 172, New York, New York, 10065, United States of America
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42
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Wang L, Bi C, Cai H, Liu B, Zhong X, Deng X, Wang T, Xiang H, Niu X, Wang D. The therapeutic effect of chlorogenic acid against Staphylococcus aureus infection through sortase A inhibition. Front Microbiol 2015; 6:1031. [PMID: 26528244 PMCID: PMC4608362 DOI: 10.3389/fmicb.2015.01031] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/11/2015] [Indexed: 12/17/2022] Open
Abstract
The emergence and wide spread of multi-drug resistant Staphylococcus aureus (S. aureus) requires the development of new therapeutic agents with alternative modes of action. Anti-virulence strategies are hoped to meet that need. Sortase A (SrtA) has attracted great interest as a potential drug target to treat infections caused by S. aureus, as many of the surface proteins displayed by SrtA function as virulence factors by mediating bacterial adhesion to specific organ tissues, invasion of host cells, and evasion of the host-immune responses. It has been suggested that inhibitors of SrtA might be promising candidates for the treatment and/or prevention of S. aureus infections. In this study, we report that chlorogenic acid (CHA), a natural compound that lacks significant anti-S. aureus activity, inhibit the activity of SrtA in vitro (IC50 = 33.86 ± 5.55 μg/ml) and the binding of S. aureus to fibrinogen (Fg). Using molecular dynamics simulations and mutagenesis assays, we further demonstrate that CHA binds to the binding sites of C184 and G192 in the SrtA. In vivo studies demonstrated that CHA prevent mice from S. aureus-induced renal abscess, resulting in a significant survival advantage. These findings indicate that CHA is a promising therapeutic compound against SrtA during S. aureus infections.
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Affiliation(s)
- Lin Wang
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Jilin University Changchun, China
| | - Chongwei Bi
- College of Animal Science, Jilin University Changchun, China
| | - Hongjun Cai
- The College of Animal Science and Technology, Jilin Agricultural University Changchun, China
| | - Bingrun Liu
- College of Animal Science, Jilin University Changchun, China
| | - Xiaobo Zhong
- College of Animal Science, Jilin University Changchun, China
| | - Xuming Deng
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Jilin University Changchun, China
| | - Tiedong Wang
- College of Animal Science, Jilin University Changchun, China
| | - Hua Xiang
- The College of Animal Science and Technology, Jilin Agricultural University Changchun, China
| | - Xiaodi Niu
- Key Laboratory of Zoonosis Research, Ministry of Education/Department of Food Quality and Safety/College of Veterinary Medicine, Jilin University Changchun, China
| | - Dacheng Wang
- College of Animal Science, Jilin University Changchun, China
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43
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Gonzalez CD, Ledo C, Giai C, Garófalo A, Gómez MI. The Sbi Protein Contributes to Staphylococcus aureus Inflammatory Response during Systemic Infection. PLoS One 2015; 10:e0131879. [PMID: 26126119 PMCID: PMC4488394 DOI: 10.1371/journal.pone.0131879] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 06/05/2015] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus is an important human pathogen that causes infections that may present high morbidity and mortality. Among its many virulence factors protein A (SpA) and Staphylococcal binding immunoglobulin protein (Sbi) bind the Fc portion of IgG interfering with opsonophagocytosis. We have previously demonstrated that SpA interacts with the TNF-α receptor (TNFR) 1 through each of the five IgG binding domains and induces the production of pro-inflammatory cytokines and chemokines. The IgG binding domains of Sbi are homologous to those of SpA, which allow us to hypothesize that Sbi might also have a role in the inflammatory response induced by S. aureus. We demonstrate that Sbi is a novel factor that participates in the induction of the inflammatory response during staphylococcal infections via TNFR1 and EGFR mediated signaling as well as downstream MAPKs. The expression of Sbi significantly contributed to IL-6 production and modulated CXCL-1 expression as well as neutrophil recruitment to the site of infection, thus demonstrating for the first time its relevance as a pro-inflammatory staphylococcal antigen in an in vivo model.
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Affiliation(s)
- Cintia Daniela Gonzalez
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Camila Ledo
- Departamento de Microbiología, Parasitología e Immunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Constanza Giai
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Ailin Garófalo
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Marisa I. Gómez
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
- Departamento de Microbiología, Parasitología e Immunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
- * E-mail:
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44
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Wang L, Bi C, Wang T, Xiang H, Chen F, Hu J, Liu B, Cai H, Zhong X, Deng X, Wang D. A coagulase-negative and non-haemolytic strain of Staphylococcus aureus for investigating the roles of SrtA in a murine model of bloodstream infection. Pathog Dis 2015; 73:ftv042. [PMID: 26054573 DOI: 10.1093/femspd/ftv042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2015] [Indexed: 12/12/2022] Open
Abstract
Sortase A (SrtA) is a cysteine transpeptidase and virulence factor from Staphylococcus aureus (S. aureus) that catalyses the attachment and display of surface proteins on the cell wall, thereby mediating bacterial adhesion to host tissues, host-cell entry and evasion of the immune response. As a result, SrtA has become an important target in the development of therapies for S. aureus infections. In this study, we used the new reference strain S. aureus Newman D2C to investigate the role of SrtA in a murine model of bloodstream infection, when the impact of coagulase and haemolysin is excluded. The results suggested that deletion of SrtA reduced the bacterial burden on the heart, liver and kidneys by blunting the host proinflammatory cytokine response at an early point in infection. Kidneys, but not heart or liver, formed abscesses on the sixth day following non-lethal infection, and this effect was diminished by SrtA mutation. These findings indicate that SrtA is a determining virulence factor in lethality and formation of renal abscesses in mice followed by S. aureus bloodstream infection. We have thus established a convenient in vitro and mouse model for developing SrtA-targeted therapeutic strategies.
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Affiliation(s)
- Lin Wang
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Chongwei Bi
- College of Animal Science, Jilin University, Changchun 130062, China
| | - Tiedong Wang
- College of Animal Science, Jilin University, Changchun 130062, China
| | - Hua Xiang
- The College of Animal Science and Technology, Jilin Agricultural University, Changchun 130033, China
| | - Fuguang Chen
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Science, Harbin 150000, China
| | - Jinping Hu
- College of Animal Science, Jilin University, Changchun 130062, China
| | - Bingrun Liu
- College of Animal Science, Jilin University, Changchun 130062, China
| | - Hongjun Cai
- The College of Animal Science and Technology, Jilin Agricultural University, Changchun 130033, China
| | - Xiaobo Zhong
- College of Animal Science, Jilin University, Changchun 130062, China
| | - Xuming Deng
- Key Laboratory of Zoonosis Research, Ministry of Education/Institute of Zoonosis/College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Dacheng Wang
- College of Animal Science, Jilin University, Changchun 130062, China
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45
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Morrison JM, John GH. Non-classical azoreductase secretion in Clostridium perfringens in response to sulfonated azo dye exposure. Anaerobe 2015; 34:34-43. [PMID: 25881497 DOI: 10.1016/j.anaerobe.2015.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 03/27/2015] [Accepted: 04/12/2015] [Indexed: 01/06/2023]
Abstract
Clostridium perfringens, a strictly anaerobic microorganism and inhabitant of the human intestine, has been shown to produce an azoreductase enzyme (AzoC), an NADH-dependent flavin oxidoreductase. This enzyme reduces azo dyes into aromatic amines, which can be carcinogenic. A significant amount of work has been completed on the activity of AzoC. Despite this, much is still unknown, including whether azoreduction of these dyes occurs intracellularly or extracellulary. A physiological study of C. perfringens involving the effect of azo dye exposure was completed to answer this question. Through exposure studies, azo dyes were found to cause cytoplasmic protein release, including AzoC, from C. perfringens in dividing and non-dividing cells. Sulfonation (negative charge) of azo dyes proved to be the key to facilitating protein release of AzoC and was found to be azo-dye-concentration-dependent. Additionally, AzoC was found to localize to the Gram-positive periplasmic region. Using a ΔazoC knockout mutant, the presence of additional azoreductases in C. perfringens was suggested. These results support the notion that the azoreduction of these dyes may occur extracellularly for the commensal C. perfringens in the intestine.
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Affiliation(s)
- Jessica M Morrison
- Oklahoma State University, Department of Microbiology and Molecular Genetics, 307 Life Science East, Stillwater, OK 74078, USA.
| | - Gilbert H John
- Oklahoma State University, Department of Microbiology and Molecular Genetics, 307 Life Science East, Stillwater, OK 74078, USA
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The essential features and modes of bacterial polar growth. Trends Microbiol 2015; 23:347-53. [PMID: 25662291 DOI: 10.1016/j.tim.2015.01.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/19/2014] [Accepted: 01/07/2015] [Indexed: 01/25/2023]
Abstract
Polar growth represents a surprising departure from the canonical dispersed cell growth model. However, we know relatively little of the underlying mechanisms governing polar growth or the requisite suite of factors that direct polar growth. Underscoring how classic doctrine can be turned on its head, the peptidoglycan layer of polar-growing bacteria features unusual crosslinks and in some species the quintessential cell division proteins FtsA and FtsZ are recruited to the growing poles. Remarkably, numerous medically important pathogens utilize polar growth, accentuating the need for intensive research in this area. Here we review models of polar growth in bacteria based on recent research in the Actinomycetales and Rhizobiales, with emphasis on Mycobacterium and Agrobacterium species.
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Cell Wall-Anchored Surface Proteins of Staphylococcus aureus: Many Proteins, Multiple Functions. Curr Top Microbiol Immunol 2015; 409:95-120. [PMID: 26667044 DOI: 10.1007/82_2015_5002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Staphylococcus aureus persistently colonizes about 20 % of the population and is intermittently associated with the remainder. The organism can cause superficial skin infections and life-threatening invasive diseases. The surface of the bacterial cell displays a variety of proteins that are covalently anchored to peptidoglycan. They perform many functions including adhesion to host cells and tissues, invasion of non-phagocytic cells, and evasion of innate immune responses. The proteins have been categorized into distinct classes based on structural and functional analysis. Many surface proteins are multifunctional. Cell wall-anchored proteins perform essential functions supporting survival and proliferation during the commensal state and during invasive infections. The ability of cell wall-anchored proteins to bind to desquamated epithelial cells is important during colonization, and the binding to fibrinogen is of particular significance in pathogenesis.
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Antiinfective therapy with a small molecule inhibitor of Staphylococcus aureus sortase. Proc Natl Acad Sci U S A 2014; 111:13517-22. [PMID: 25197057 DOI: 10.1073/pnas.1408601111] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is the most frequent cause of hospital-acquired infection, which manifests as surgical site infections, bacteremia, and sepsis. Due to drug-resistance, prophylaxis of MRSA infection with antibiotics frequently fails or incites nosocomial diseases such as Clostridium difficile infection. Sortase A is a transpeptidase that anchors surface proteins in the envelope of S. aureus, and sortase mutants are unable to cause bacteremia or sepsis in mice. Here we used virtual screening and optimization of inhibitor structure to identify 3-(4-pyridinyl)-6-(2-sodiumsulfonatephenyl)[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole and related compounds, which block sortase activity in vitro and in vivo. Sortase inhibitors do not affect in vitro staphylococcal growth yet protect mice against lethal S. aureus bacteremia. Thus, sortase inhibitors may be useful as antiinfective therapy to prevent hospital-acquired S. aureus infection in high-risk patients without the side effects of antibiotics.
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Schneewind O, Missiakas D. Sec-secretion and sortase-mediated anchoring of proteins in Gram-positive bacteria. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1843:1687-97. [PMID: 24269844 PMCID: PMC4031296 DOI: 10.1016/j.bbamcr.2013.11.009] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 11/01/2013] [Accepted: 11/13/2013] [Indexed: 01/17/2023]
Abstract
Signal peptide-driven secretion of precursor proteins directs polypeptides across the plasma membrane of bacteria. Two pathways, Sec- and SRP-dependent, converge at the SecYEG translocon to thread unfolded precursor proteins across the membrane, whereas folded preproteins are routed via the Tat secretion pathway. Gram-positive bacteria lack an outer membrane and are surrounded by a rigid layer of peptidoglycan. Interactions with their environment are mediated by proteins that are retained in the cell wall, often through covalent attachment to the peptidoglycan. In this review, we describe the mechanisms for both Sec-dependent secretion and sortase-dependent assembly of proteins in the envelope of Gram-positive bacteria. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Affiliation(s)
- Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, IL 60637, USA.
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Jensen H, Roos S, Jonsson H, Rud I, Grimmer S, van Pijkeren JP, Britton RA, Axelsson L. Role of Lactobacillus reuteri cell and mucus-binding protein A (CmbA) in adhesion to intestinal epithelial cells and mucus in vitro. MICROBIOLOGY-SGM 2014; 160:671-681. [PMID: 24473252 DOI: 10.1099/mic.0.073551-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Lactobacillus reuteri, a symbiotic inhabitant of the gastrointestinal tract in humans and animals, is marketed as a probiotic. The ability to adhere to intestinal epithelial cells and mucus is an interesting property with regard to probiotic features such as colonization of the gastrointestinal tract and interaction with the host. Here, we present a study performed to elucidate the role of sortase (SrtA), four putative sortase-dependent proteins (SDPs), and one C-terminal membrane-anchored cell surface protein of Lactobacillus reuteri ATCC PTA 6475 in adhesion to Caco-2 cells and mucus in vitro. This included mutagenesis of the genes encoding these proteins and complementation of mutants. A null mutation in hmpref0536_10255 encoding srtA resulted in significantly reduced adhesion to Caco-2 cells and mucus, indicating involvement of SDPs in adhesion. Evaluation of the bacterial adhesion revealed that of the five putative surface protein mutants tested, only a null mutation in the hmpref0536_10633 gene, encoding a putative SDP with an LPxTG motif, resulted in a significant loss of adhesion to both Caco-2 cells and mucus. Complementation with the functional gene on a plasmid restored adhesion to Caco-2 cells. However, complete restoration of adhesion to mucus was not achieved. Overexpression of hmpref0536_10633 in strain ATCC PTA 6475 resulted in an increased adhesion to Caco-2 cells and mucus compared with the WT strain. We conclude from these results that, among the putative surface proteins tested, the protein encoded by hmpref0536_10633 plays a critical role in binding of Lactobacillus reuteri ATCC PTA 6475 to Caco-2 cells and mucus. Based on this, we propose that this LPxTG motif containing protein should be referred to as cell and mucus binding protein A (CmbA).
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Affiliation(s)
- Hanne Jensen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO Box 5003, 1432 Ås, Norway.,Nofima - Norwegian Institute of Food, Fisheries, and Aquaculture Research, PO Box 210, 1431 Ås, Norway
| | - Stefan Roos
- Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7025, 750 07 Uppsala, Sweden
| | - Hans Jonsson
- Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7025, 750 07 Uppsala, Sweden
| | - Ida Rud
- Nofima - Norwegian Institute of Food, Fisheries, and Aquaculture Research, PO Box 210, 1431 Ås, Norway
| | - Stine Grimmer
- Nofima - Norwegian Institute of Food, Fisheries, and Aquaculture Research, PO Box 210, 1431 Ås, Norway
| | - Jan-Peter van Pijkeren
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Robert A Britton
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Lars Axelsson
- Nofima - Norwegian Institute of Food, Fisheries, and Aquaculture Research, PO Box 210, 1431 Ås, Norway
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