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Lai LY, Satishkumar N, Cardozo S, Hemmadi V, Marques LB, Huang L, Filipe SR, Pinho MG, Chambers HF, Chatterjee SS. Altered PBP4 and GdpP functions synergistically mediate MRSA-like high-level, broad-spectrum β-lactam resistance in Staphylococcus aureus. mBio 2024; 15:e0288923. [PMID: 38530033 PMCID: PMC11077961 DOI: 10.1128/mbio.02889-23] [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: 10/24/2023] [Accepted: 03/04/2024] [Indexed: 03/27/2024] Open
Abstract
Infections caused by Staphylococcus aureus are a leading cause of mortality worldwide. S. aureus infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are particularly difficult to treat due to their resistance to next-generation β-lactams (NGBs) such as methicillin, nafcillin, and oxacillin. Resistance to NGBs, which is alternatively known as broad-spectrum β-lactam resistance, is classically mediated by PBP2a, a penicillin-binding protein encoded by mecA (or mecC) in MRSA. Thus, presence of mec genes among S. aureus spp. serves as the predictor of resistance to NGBs and facilitates determination of the proper therapeutic strategy for a staphylococcal infection. Although far less appreciated, mecA-deficient S. aureus strains can also exhibit NGB resistance. These strains, which are collectively termed as methicillin-resistant lacking mec (MRLM), are currently being identified in increasing numbers among natural resistant isolates of S. aureus. The mechanism/s through which MRLMs produce resistance to NGBs remains unknown. In this study, we demonstrate that mutations that alter PBP4 and GdpP functions, which are often present among MRLMs, can synergistically mediate resistance to NGBs. Furthermore, our results unravel that this novel mechanism potentially enables MRLMs to produce resistance toward NGBs at levels comparable to those of MRSAs. Our study provides a fresh new perspective about alternative mechanisms of NGB resistance, challenging our current overall understanding of high-level, broad-spectrum β-lactam resistance in S. aureus. It thus suggests reconsideration of the current approach toward diagnosis and treatment of β-lactam-resistant S. aureus infections. IMPORTANCE In Staphylococcus aureus, high-level, broad-spectrum resistance to β-lactams such as methicillin, also referred to as methicillin resistance, is largely attributed to mecA. This study demonstrates that S. aureus strains that lack mecA but contain mutations that functionally alter PBP4 and GdpP can also mediate high-level, broad-spectrum resistance to β-lactams. Resistance brought about by the synergistic action of functionally altered PBP4 and GdpP was phenotypically comparable to that displayed by mecA, as seen by increased bacterial survival in the presence of β-lactams. An analysis of mutations detected in naturally isolated strains of S. aureus revealed that a significant proportion of them had similar pbp4 and GGDEF domain protein containing phosphodiesterase (gdpP) mutations, making this study clinically significant. This study not only identifies important players of non-classical mechanisms of β-lactam resistance but also indicates reconsideration of current clinical diagnosis and treatment protocols of S. aureus infections.
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Affiliation(s)
- Li-Yin Lai
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Nidhi Satishkumar
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Sasha Cardozo
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Vijay Hemmadi
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Leonor B. Marques
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Liusheng Huang
- Department of Clinical Pharmacy, Drug Research Unit, University of California, San Francisco, California, USA
| | - Sergio R. Filipe
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Mariana G. Pinho
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Henry F. Chambers
- Division of Infectious Diseases, School of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Som S. Chatterjee
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
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Lai LY, Satishkumar N, Cardozo S, Hemmadi V, Marques LB, Huang L, Filipe SR, Pinho MG, Chambers HF, Chatterjee SS. Altered PBP4 and GdpP functions synergistically mediate MRSA-like high-level, broad-spectrum β-lactam resistance in Staphylococcus aureus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.26.564222. [PMID: 37961375 PMCID: PMC10634853 DOI: 10.1101/2023.10.26.564222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Infections caused by Staphylococcus aureus are a leading cause of mortality worldwide. S. aureus infections caused by Methicillin-Resistant Staphylococcus aureus (MRSA) are particularly difficult to treat due to their resistance to Next Generation β-lactams (NGB) such as Methicillin, Nafcillin, Oxacillin etc. Resistance to NGBs, which is alternatively known as broad-spectrum β-lactam resistance is classically mediated by PBP2a, a Penicillin-Binding Protein encoded by mecA (or mecC) in MRSA. Thus, presence of mec genes among S. aureus serves as the predictor of resistance to NGBs and facilitates determination of the proper therapeutic strategy for a staphylococcal infection. Although far less appreciated, mecA deficient S. aureus strains can also exhibit NGB resistance. These strains, which are collectively termed as Methicillin-Resistant Lacking mec (MRLM) are currently being identified in increasing numbers among natural resistant isolates of S. aureus. The mechanism/s through which MRLMs produce resistance to NGBs remains unknown. In this study, we demonstrate that mutations that alter PBP4 and GdpP functions, which are often present among MRLMs can synergistically mediate resistance to NGBs. Furthermore, our results unravel that this novel mechanism potentially enables MRLMs to produce resistance towards NGBs at levels comparable to that of MRSAs. Our study, provides a fresh new perspective about alternative mechanisms of NGBs resistance, challenging our current overall understanding of high-level, broad-spectrum β-lactam resistance in S. aureus. It thus suggests reconsideration of the current approach towards diagnosis and treatment of β-lactam resistant S. aureus infections.
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Affiliation(s)
- Li-Yin Lai
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, USA
| | - Nidhi Satishkumar
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, USA
| | - Sasha Cardozo
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, USA
| | - Vijay Hemmadi
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, USA
| | - Leonor B. Marques
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Liusheng Huang
- Drug Research Unit, Department of Clinical Pharmacy, University of California, San Francisco, San Francisco, CA, USA
| | - Sergio R. Filipe
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Mariana G. Pinho
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Henry F. Chambers
- Division of Infectious Diseases, School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Som S. Chatterjee
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, USA
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3
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Zhao L, Niu J, Feng D, Wang X, Zhang R. Immune functions of pattern recognition receptors in Lepidoptera. Front Immunol 2023; 14:1203061. [PMID: 37398667 PMCID: PMC10312389 DOI: 10.3389/fimmu.2023.1203061] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/05/2023] [Indexed: 07/04/2023] Open
Abstract
Pattern recognition receptors (PRRs), as the "sensors" in the immune response, play a prominent role in recognizing pathogen-associated molecular patterns (PAMPs) and initiating an effective defense response to pathogens in Lepidoptera. It is becoming increasingly clear that damage-associated molecular patterns (DAMPs) normally play a physiological role within cells; however, when exposed to extracellular, they may become "part-time" critical signals of the immune response. Based on research in recent years, we review herein typical PRRs of Lepidoptera, including peptidoglycan recognition protein (PGRP), gram-negative binding protein (GNBP), β-1,3-glucan recognition protein (βGRP), C-type lectin (CTL), and scavenger receptor (SR). We also outline the ways in which DAMPs participate in the immune response and the correlation between PRRs and immune escape. Taken together, these findings suggest that the role of PRRs in insect innate immunity may be much greater than expected and that it is possible to recognize a broader range of signaling molecules.
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Affiliation(s)
- Lin Zhao
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Jinlan Niu
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Disong Feng
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Xialu Wang
- School of Medical Devices, Shenyang Pharmaceutical University, Shenyang, China
| | - Rong Zhang
- School of Life Science and Bio-Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
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4
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Sensing microbial infections in the Drosophila melanogaster genetic model organism. Immunogenetics 2022; 74:35-62. [DOI: 10.1007/s00251-021-01239-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 11/20/2021] [Indexed: 12/17/2022]
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5
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The Mycobacteriophage Ms6 LysB N-Terminus Displays Peptidoglycan Binding Affinity. Viruses 2021; 13:v13071377. [PMID: 34372584 PMCID: PMC8309991 DOI: 10.3390/v13071377] [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: 06/07/2021] [Revised: 07/01/2021] [Accepted: 07/12/2021] [Indexed: 11/17/2022] Open
Abstract
Double-stranded DNA bacteriophages end their lytic cycle by disrupting the host cell envelope, which allows the release of the virion progeny. Each phage must synthesize lysis proteins that target each cell barrier to phage release. In addition to holins, which permeabilize the cytoplasmic membrane, and endolysins, which disrupt the peptidoglycan (PG), mycobacteriophages synthesize a specific lysis protein, LysB, capable of detaching the outer membrane from the complex cell wall of mycobacteria. The family of LysB proteins is highly diverse, with many members presenting an extended N-terminus. The N-terminal region of mycobacteriophage Ms6 LysB shows structural similarity to the PG-binding domain (PGBD) of the φKZ endolysin. A fusion of this region with enhanced green fluorescent protein (Ms6LysBPGBD-EGFP) was shown to bind to Mycobacterium smegmatis, Mycobacterium vaccae, Mycobacterium bovis BGC and Mycobacterium tuberculosis H37Ra cells pretreated with SDS or Ms6 LysB. In pulldown assays, we demonstrate that Ms6 LysB and Ms6LysBPGBD-EGFP bind to purified peptidoglycan of M. smegmatis, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis, demonstrating affinity to PG of the A1γ chemotype. An infection assay with an Ms6 mutant producing a truncated version of LysB lacking the first 90 amino acids resulted in an abrupt lysis. These results clearly demonstrate that the N-terminus of Ms6 LysB binds to the PG.
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PGRP-LB: An Inside View into the Mechanism of the Amidase Reaction. Int J Mol Sci 2021; 22:ijms22094957. [PMID: 34066955 PMCID: PMC8124813 DOI: 10.3390/ijms22094957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/02/2021] [Accepted: 05/03/2021] [Indexed: 11/23/2022] Open
Abstract
Peptidoglycan recognition proteins (PGRPs) are ubiquitous among animals and play pivotal functions in insect immunity. Non-catalytic PGRPs are involved in the activation of immune pathways by binding to the peptidoglycan (PGN), whereas amidase PGRPs are capable of cleaving the PGN into non-immunogenic compounds. Drosophila PGRP-LB belongs to the amidase PGRPs and downregulates the immune deficiency (IMD) pathway by cleaving meso-2,6-diaminopimelic (meso-DAP or DAP)-type PGN. While the recognition process is well analyzed for the non-catalytic PGRPs, little is known about the enzymatic mechanism for the amidase PGRPs, despite their essential function in immune homeostasis. Here, we analyzed the specific activity of different isoforms of Drosophila PGRP-LB towards various PGN substrates to understand their specificity and role in Drosophila immunity. We show that these isoforms have similar activity towards the different compounds. To analyze the mechanism of the amidase activity, we performed site directed mutagenesis and solved the X-ray structures of wild-type Drosophila PGRP-LB and its mutants, with one of these structures presenting a protein complexed with the tracheal cytotoxin (TCT), a muropeptide derived from the PGN. Only the Y78F mutation abolished the PGN cleavage while other mutations reduced the activity solely. Together, our findings suggest the dynamic role of the residue Y78 in the amidase mechanism by nucleophilic attack through a water molecule to the carbonyl group of the amide function destabilized by Zn2+.
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Vaz F, Kounatidis I, Covas G, Parton RM, Harkiolaki M, Davis I, Filipe SR, Ligoxygakis P. Accessibility to Peptidoglycan Is Important for the Recognition of Gram-Positive Bacteria in Drosophila. Cell Rep 2020; 27:2480-2492.e6. [PMID: 31116990 PMCID: PMC6533200 DOI: 10.1016/j.celrep.2019.04.103] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 03/19/2019] [Accepted: 04/23/2019] [Indexed: 11/16/2022] Open
Abstract
In Drosophila, it is thought that peptidoglycan recognition proteins (PGRPs) SA and LC structurally discriminate between bacterial peptidoglycans with lysine (Lys) or diaminopimelic (DAP) acid, respectively, thus inducing differential antimicrobial transcription response. Here, we find that accessibility to PG at the cell wall plays a central role in immunity to infection. When wall teichoic acids (WTAs) are genetically removed from S. aureus (Lys type) and Bacillus subtilis (DAP type), thus increasing accessibility, the binding of both PGRPs to either bacterium is increased. PGRP-SA and -LC double mutant flies are more susceptible to infection with both WTA-less bacteria. In addition, WTA-less bacteria grow better in PGRP-SA/-LC double mutant flies. Finally, infection with WTA-less bacteria abolishes any differential activation of downstream antimicrobial transcription. Our results indicate that accessibility to cell wall PG is a major factor in PGRP-mediated immunity and may be the cause for discrimination between classes of pathogens.
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Affiliation(s)
- Filipa Vaz
- Department of Biochemistry, University of Oxford, South Parks Rd., OX1 3QU Oxford, UK; Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras, Portugal
| | - Ilias Kounatidis
- Department of Biochemistry, University of Oxford, South Parks Rd., OX1 3QU Oxford, UK; Diamond Light Source, Ltd., Harwell Science and Innovation Campus, OX11 0DE Didcot, UK
| | - Gonçalo Covas
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras, Portugal; UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Richard M Parton
- Department of Biochemistry, University of Oxford, South Parks Rd., OX1 3QU Oxford, UK
| | - Maria Harkiolaki
- Diamond Light Source, Ltd., Harwell Science and Innovation Campus, OX11 0DE Didcot, UK
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, South Parks Rd., OX1 3QU Oxford, UK
| | - Sergio Raposo Filipe
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras, Portugal; UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
| | - Petros Ligoxygakis
- Department of Biochemistry, University of Oxford, South Parks Rd., OX1 3QU Oxford, UK.
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TmPGRP-SA regulates Antimicrobial Response to Bacteria and Fungi in the Fat Body and Gut of Tenebrio molitor. Int J Mol Sci 2020; 21:ijms21062113. [PMID: 32204438 PMCID: PMC7139795 DOI: 10.3390/ijms21062113] [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: 02/24/2020] [Revised: 03/09/2020] [Accepted: 03/17/2020] [Indexed: 12/13/2022] Open
Abstract
Antimicrobial immune response is mediated by a signal-transducing sensor, peptidoglycan recognition protein-SA (PGRP-SA), that can recognize non-self molecules. Although several studies have focused on the involvement of Drosophila PGRP-SA in antimicrobial peptide (AMP) expression in response to infections, studies on its role in Tenebrio molitor are lacking. Here, we present a functional analysis of T. molitor PGRP-SA (TmPGRP-SA). In the absence of microbes, TmPGRP-SA was highly expressed in the late-larval fat body, followed by hemocytes, and gut. Interestingly, following Escherichia coli, Staphylococcus aureus, and Candida albicans infections, the mRNA level of TmPGRP-SA was significantly upregulated in both the fat body and gut. TmPGRP-SA silencing had a significant effect on the mortality rates for all the microbes tested. Moreover, TmPGRP-SA is required for regulating the expression of eight AMP genes namely TmTenecin-1, -2, and -4; TmDefensin-1 and -2; TmColeoptericin-1; and TmAttacin-1b and -2 in the fat body in response to E. coli and S. aureus infections. TmPGRP-SA is essential for the transcription of TmTenecin-2, -4; TmDefensin-2; TmColeoptericin-1, -2; and TmAttacin-1a, -1b, and -2 in the gut upon E. coli and C. albicans infections. However, TmPGRP-SA does not regulate AMP expression in the hemocytes. Additionally, TmDorsal isoform X2, a downstream Toll transcription factor, was downregulated in TmPGRP-SA-silenced larval fat body following E. coli and S. aureus challenges, and in the gut following E. coli and C. albicans challenges.
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Lu Y, Su F, Li Q, Zhang J, Li Y, Tang T, Hu Q, Yu XQ. Pattern recognition receptors in Drosophila immune responses. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 102:103468. [PMID: 31430488 DOI: 10.1016/j.dci.2019.103468] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/07/2019] [Accepted: 08/16/2019] [Indexed: 05/08/2023]
Abstract
Insects, which lack the adaptive immune system, have developed sophisticated innate immune system consisting of humoral and cellular immune responses to defend against invading microorganisms. Non-self recognition of microbes is the front line of the innate immune system. Repertoires of pattern recognition receptors (PRRs) recognize the conserved pathogen-associated molecular patterns (PAMPs) present in microbes, such as lipopolysaccharide (LPS), peptidoglycan (PGN), lipoteichoic acid (LTA) and β-1, 3-glucans, and induce innate immune responses. In this review, we summarize current knowledge of the structure, classification and roles of PRRs in innate immunity of the model organism Drosophila melanogaster, focusing mainly on the peptidoglycan recognition proteins (PGRPs), Gram-negative bacteria-binding proteins (GNBPs), scavenger receptors (SRs), thioester-containing proteins (TEPs), and lectins.
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Affiliation(s)
- Yuzhen Lu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China; Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Fanghua Su
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Qilin Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jie Zhang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yanjun Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Ting Tang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Qihao Hu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xiao-Qiang Yu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China; Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China.
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Jensen C, Bæk KT, Gallay C, Thalsø-Madsen I, Xu L, Jousselin A, Ruiz Torrubia F, Paulander W, Pereira AR, Veening JW, Pinho MG, Frees D. The ClpX chaperone controls autolytic splitting of Staphylococcus aureus daughter cells, but is bypassed by β-lactam antibiotics or inhibitors of WTA biosynthesis. PLoS Pathog 2019; 15:e1008044. [PMID: 31518377 PMCID: PMC6760813 DOI: 10.1371/journal.ppat.1008044] [Citation(s) in RCA: 20] [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: 07/02/2019] [Revised: 09/25/2019] [Accepted: 08/26/2019] [Indexed: 12/02/2022] Open
Abstract
β-lactam antibiotics interfere with cross-linking of the bacterial cell wall, but the killing mechanism of this important class of antibiotics is not fully understood. Serendipitously we found that sub-lethal doses of β-lactams rescue growth and prevent spontaneous lysis of Staphylococcus aureus mutants lacking the widely conserved chaperone ClpX, and we reasoned that a better understanding of the clpX phenotypes could provide novel insights into the downstream effects of β-lactam binding to the PBP targets. Super-resolution imaging revealed that clpX cells display aberrant septum synthesis, and initiate daughter cell separation prior to septum completion at 30°C, but not at 37°C, demonstrating that ClpX becomes critical for coordinating the S. aureus cell cycle as the temperature decreases. FtsZ localization and dynamics were not affected in the absence of ClpX, suggesting that ClpX affects septum formation and autolytic activation downstream of Z-ring formation. Interestingly, oxacillin antagonized the septum progression defects of clpX cells and prevented lysis of prematurely splitting clpX cells. Strikingly, inhibitors of wall teichoic acid (WTA) biosynthesis that work synergistically with β-lactams to kill MRSA synthesis also rescued growth of the clpX mutant, as did genetic inactivation of the gene encoding the septal autolysin, Sle1. Taken together, our data support a model in which Sle1 causes premature splitting and lysis of clpX daughter cells unless Sle1-dependent lysis is antagonized by β-lactams or by inhibiting an early step in WTA biosynthesis. The finding that β-lactams and inhibitors of WTA biosynthesis specifically prevent lysis of a mutant with dysregulated autolytic activity lends support to the idea that PBPs and WTA biosynthesis play an important role in coordinating cell division with autolytic splitting of daughter cells, and that β-lactams do not kill S. aureus simply by weakening the cell wall. The bacterium Staphylococcus aureus is a major cause of human disease, and the rapid spread of S. aureus strains that are resistant to almost all β-lactam antibiotics has made treatment increasingly difficult. β-lactams interfere with cross-linking of the bacterial cell wall but the killing mechanism of this important class of antibiotics is not fully understood. Here we provide novel insight into this topic by examining a defined S. aureus mutant that has the unusual property of growing markedly better in the presence of β-lactams. Without β-lactams this mutant dies spontaneously at a high frequency due to premature separation of daughter cells during cell division. Cell death of the mutant can, however, be prevented either by exposure to β-lactam antibiotics or by inhibiting synthesis of wall teichoic acid, a major component of the cell wall in Gram-positive bacteria with a conserved role in activation of autolytic splitting of daughter cells. The finding that β-lactam antibiotics can prevent lysis of a mutant with deregulated activity of autolytic enzymes involved in daughter cell splitting, emphasizes the idea that β-lactams interfere with the coordination between cell division and daughter cell splitting, and do not kill S. aureus simply by weakening the cell wall.
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Affiliation(s)
- Camilla Jensen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristoffer T. Bæk
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Clement Gallay
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Ida Thalsø-Madsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lijuan Xu
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ambre Jousselin
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Fernando Ruiz Torrubia
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Wilhelm Paulander
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ana R. Pereira
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Mariana G. Pinho
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Dorte Frees
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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11
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Caicedo PA, Serrato IM, Sim S, Dimopoulos G, Coatsworth H, Lowenberger C, Ocampo CB. Immune response-related genes associated to blocking midgut dengue virus infection in Aedes aegypti strains that differ in susceptibility. INSECT SCIENCE 2019; 26:635-648. [PMID: 29389079 DOI: 10.1111/1744-7917.12573] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 12/19/2017] [Accepted: 01/15/2018] [Indexed: 06/07/2023]
Abstract
Aedes (Stegomyia) aegypti, the principal global vector of dengue viruses, has differences in its susceptibility to dengue virus infection. We compared the global expression of genes in the midguts of Colombian Ae. aegypti dengue-susceptible (Cali-S) and dengue-refractory (Cali-MIB) field derived strains after ingesting either a sugarmeal, a bloodmeal, or a bloodmeal containing dengue virus serotype 2 (DENV-2). Microarray-based transcriptome analysis among treatments indicated a total of 4725 transcripts with differential expression between the two strains. Eleven genes were selected from different functional groups based on their significant up or down expression levels as well as reports in the literature suggesting they are associated with dengue virus elimination. We measured mRNA abundance of these 11 genes at 0, 8, 24, and 36 h postinfection using quantitative real time PCR (qPCR) to confirm the microarray results and assess any temporal patterns. Four genes were selected (Gram-negative binding protein-GNBP [AAEL009176], Niemann Pick Type-C2-NPC2 [AAEL015136], Keratinocyte lectin [AAEL009842], and Cathepsin-b [AAEL007585]) for knockdown experiments using RNA interference (RNAi) methodology to determine the phenotype (DENV-2 susceptible or refractory). Silencing GNBP, Cathepsin-b and Keratinocyte lectin reduced the percentage of mosquitoes with disseminated virus in the Cali-S strain to 8%, 20%, and 12% respectively compared with 96% in the controls. Silencing of NPC2 increased the percentage of mosquitos with disseminated virus infections in Cali-MIB to 66% compared with 35% in the controls. This study provides insight into genes that may contribute to the Cali-S susceptible and Cali-MIB refractory phenotypes in Ae. aegypti.
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Affiliation(s)
- Paola A Caicedo
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
| | - Idalba Mildred Serrato
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
| | - Shuzhen Sim
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Heather Coatsworth
- Department of Biological Sciences, Simon Fraser University, Burnaby, Canada
| | - Carl Lowenberger
- Department of Biological Sciences, Simon Fraser University, Burnaby, Canada
| | - Clara B Ocampo
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
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12
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Reichmann NT, Tavares AC, Saraiva BM, Jousselin A, Reed P, Pereira AR, Monteiro JM, Sobral RG, VanNieuwenhze MS, Fernandes F, Pinho MG. SEDS-bPBP pairs direct lateral and septal peptidoglycan synthesis in Staphylococcus aureus. Nat Microbiol 2019; 4:1368-1377. [PMID: 31086309 DOI: 10.1038/s41564-019-0437-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 03/25/2019] [Indexed: 11/09/2022]
Abstract
Peptidoglycan (PGN) is the major component of the bacterial cell wall, a structure that is essential for the physical integrity and shape of the cell. Bacteria maintain cell shape by directing PGN incorporation to distinct regions of the cell, namely, through the localization of late-stage PGN synthesis proteins. These include two key protein families, SEDS transglycosylases and bPBP transpeptidases, proposed to function in cognate pairs. Rod-shaped bacteria have two SEDS-bPBP pairs, involved in elongation and division. Here, we elucidate why coccoid bacteria, such as Staphylococcus aureus, also possess two SEDS-bPBP pairs. We determined that S. aureus RodA-PBP3 and FtsW-PBP1 probably constitute cognate pairs of interacting proteins. A lack of RodA-PBP3 resulted in more spherical cells due to deficient sidewall PGN synthesis, whereas depletion of FtsW-PBP1 arrested normal septal PGN incorporation. Although PBP1 is an essential protein, a mutant lacking PBP1 transpeptidase activity is viable, showing that this protein has a second function. We propose that the FtsW-PBP1 pair has a role in stabilizing the divisome at midcell. In the absence of these proteins, the divisome appears as multiple rings or arcs that drive lateral PGN incorporation, leading to cell elongation. We conclude that RodA-PBP3 and FtsW-PBP1 mediate sidewall and septal PGN incorporation, respectively, and that their activity must be balanced to maintain coccoid morphology.
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Affiliation(s)
- Nathalie T Reichmann
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Andreia C Tavares
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Bruno M Saraiva
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ambre Jousselin
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Patricia Reed
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ana R Pereira
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - João M Monteiro
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Rita G Sobral
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.,Departamento de Ciências da Vida e UCIBIO-REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | | | - Fábio Fernandes
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal.,Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Mariana G Pinho
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
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13
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Schlöffel MA, Käsbauer C, Gust AA. Interplay of plant glycan hydrolases and LysM proteins in plant-Bacteria interactions. Int J Med Microbiol 2019; 309:252-257. [PMID: 31079999 DOI: 10.1016/j.ijmm.2019.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 04/10/2019] [Accepted: 04/25/2019] [Indexed: 12/18/2022] Open
Abstract
Plants are always found together with bacteria and other microbes. Although plants can be attacked by phytopathogenic bacteria, they are more often engaged in neutral or mutualistic bacterial interactions. In the soil, plants associate with rhizobia or other plant growth promoting rhizosphere bacteria; above ground, bacteria colonise plants as epi- and endophytes. For mounting appropriate responses, such as permitting colonisation by beneficial symbionts while at the same time fending off pathogenic invaders, plants need to distinguish between the "good" and the "bad". Plants make use of proteins containing the lysin motif (LysM) for perception of N-acetylglucosamine containing carbohydrate structures, such as chitooligosaccharides functioning as symbiotic nodulation factors or bacterial peptidoglycan. Moreover, plant hydrolytic enzymes of the chitinase family, which are able to cleave bacterial peptidoglycan or chitooligosaccharides, are essential for cellular signalling induced by rhizobial nodulation factors during symbiosis as well as bacterial peptidoglycan during pathogenesis. Hence, LysM receptors seem to work in concert with hydrolytic enzymes that fine-tune ligand availability to either allow symbiotic interactions or trigger plant immunity.
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Affiliation(s)
- Maria A Schlöffel
- Plant Biochemistry, Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany
| | - Christoph Käsbauer
- Plant Biochemistry, Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany
| | - Andrea A Gust
- Plant Biochemistry, Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany.
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14
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Monteiro JM, Covas G, Rausch D, Filipe SR, Schneider T, Sahl HG, Pinho MG. The pentaglycine bridges of Staphylococcus aureus peptidoglycan are essential for cell integrity. Sci Rep 2019; 9:5010. [PMID: 30899062 PMCID: PMC6428869 DOI: 10.1038/s41598-019-41461-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 03/07/2019] [Indexed: 02/04/2023] Open
Abstract
Bacterial cells are surrounded by cell wall, whose main component is peptidoglycan (PG), a macromolecule that withstands the internal turgor of the cell. PG composition can vary considerably between species. The Gram-positive pathogen Staphylococcus aureus possesses highly crosslinked PG due to the presence of cross bridges containing five glycines, which are synthesised by the FemXAB protein family. FemX adds the first glycine of the cross bridge, while FemA and FemB add the second and the third, and the fourth and the fifth glycines, respectively. Of these, FemX was reported to be essential. To investigate the essentiality of FemAB, we constructed a conditional S. aureus mutant of the femAB operon. Depletion of femAB was lethal, with cells appearing as pseudomulticellular forms that eventually lyse due to extensive membrane rupture. This deleterious effect was mitigated by drastically increasing the osmolarity of the medium, indicating that pentaglycine crosslinks are required for S. aureus cells to withstand internal turgor. Despite the absence of canonical membrane targeting domains, FemA has been shown to localise at the membrane. To study its mechanism of localisation, we constructed mutants in key residues present in the putative transferase pocket and the α6 helix of FemA, possibly involved in tRNA binding. Mutations in the α6 helix led to a sharp decrease in protein activity in vivo and in vitro but did not impair correct membrane localisation, indicating that FemA activity is not required for localisation. Our data indicates that, contrarily to what was previously thought, S. aureus cells do not survive in the absence of a pentaglycine cross bridge.
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Affiliation(s)
- João M Monteiro
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Gonçalo Covas
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.,UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Daniela Rausch
- Institute of Pharmaceutical Microbiology, University of Bonn, 53115, Bonn, Germany
| | - Sérgio R Filipe
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.,UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Tanja Schneider
- Institute of Pharmaceutical Microbiology, University of Bonn, 53115, Bonn, Germany
| | - Hans-Georg Sahl
- Institute of Pharmaceutical Microbiology, University of Bonn, 53115, Bonn, Germany
| | - Mariana G Pinho
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
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15
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Nie L, Cai SY, Shao JZ, Chen J. Toll-Like Receptors, Associated Biological Roles, and Signaling Networks in Non-Mammals. Front Immunol 2018; 9:1523. [PMID: 30034391 PMCID: PMC6043800 DOI: 10.3389/fimmu.2018.01523] [Citation(s) in RCA: 172] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/19/2018] [Indexed: 01/18/2023] Open
Abstract
The innate immune system is the first line of defense against pathogens, which is initiated by the recognition of pathogen-associated molecular patterns (PAMPs) and endogenous damage-associated molecular patterns (DAMPs) by pattern recognition receptors (PRRs). Among all the PRRs identified, the toll-like receptors (TLRs) are the most ancient class, with the most extensive spectrum of pathogen recognition. Since the first discovery of Toll in Drosophila melanogaster, numerous TLRs have been identified across a wide range of invertebrate and vertebrate species. It seems that TLRs, the signaling pathways that they initiate, or related adaptor proteins are essentially conserved in a wide variety of organisms, from Porifera to mammals. Molecular structure analysis indicates that most TLR homologs share similar domain patterns and that some vital participants of TLR signaling co-evolved with TLRs themselves. However, functional specification and emergence of new signaling pathways, as well as adaptors, did occur during evolution. In addition, ambiguities and gaps in knowledge still exist regarding the TLR network, especially in lower organisms. Hence, a systematic review from the comparative angle regarding this tremendous signaling system and the scenario of evolutionary pattern across Animalia is needed. In the current review, we present overview and possible evolutionary patterns of TLRs in non-mammals, hoping that this will provide clues for further investigations in this field.
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Affiliation(s)
- Li Nie
- Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Shi-Yu Cai
- Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Jian-Zhong Shao
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jiong Chen
- Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo, China
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16
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Rao XJ, Zhan MY, Pan YM, Liu S, Yang PJ, Yang LL, Yu XQ. Immune functions of insect βGRPs and their potential application. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 83:80-88. [PMID: 29229443 DOI: 10.1016/j.dci.2017.12.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 12/06/2017] [Accepted: 12/08/2017] [Indexed: 06/07/2023]
Abstract
Insects rely completely on the innate immune system to sense the foreign bodies and to mount the immune responses. Germ-line encoded pattern recognition receptors play crucial roles in recognizing pathogen-associated molecular patterns. Among them, β-1,3-glucan recognition proteins (βGRPs) and gram-negative bacteria-binding proteins (GNBPs) belong to the same pattern recognition receptor family, which can recognize β-1,3-glucans. Typical insect βGRPs are comprised of a tandem carbohydrate-binding module in the N-terminal and a glucanase-like domain in the C-terminal. The former can recognize triple-helical β-1,3-glucans, whereas the latter, which normally lacks the enzymatic activity, can recruit adapter proteins to initiate the protease cascade. According to studies, insect βGRPs possess at least three types of functions. Firstly, some βGRPs cooperate with peptidoglycan recognition proteins to recognize the lysine-type peptidoglycans upstream of the Toll pathway. Secondly, some directly recognize fungal β-1,3-glucans to activate the Toll pathway and melanization. Thirdly, some form the 'attack complexes' with other immune effectors to promote the antifungal defenses. The current review will focus on the discovery of insect βGRPs, functions of some well-characterized members, structure-function studies and their potential application.
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Affiliation(s)
- Xiang-Jun Rao
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China.
| | - Ming-Yue Zhan
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Yue-Min Pan
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Su Liu
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Pei-Jin Yang
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Li-Ling Yang
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Xiao-Qiang Yu
- Institute of Insect Science and Technology & School of Life Sciences, South China Normal University, Guangzhou 510631, China
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17
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Tobias NJ, Mishra B, Gupta DK, Sharma R, Thines M, Stinear TP, Bode HB. Genome comparisons provide insights into the role of secondary metabolites in the pathogenic phase of the Photorhabdus life cycle. BMC Genomics 2016; 17:537. [PMID: 27488257 PMCID: PMC4971723 DOI: 10.1186/s12864-016-2862-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 06/29/2016] [Indexed: 01/28/2023] Open
Abstract
Background Bacteria within the genus Photorhabdus maintain mutualistic symbioses with nematodes in complicated lifecycles that also involves insect pathogenic phases. Intriguingly, these bacteria are rich in biosynthetic gene clusters that produce compounds with diverse biological activities. As a basis to better understand the life cycles of Photorhabdus we sequenced the genomes of two recently discovered representative species and performed detailed genomic comparisons with five publically available genomes. Results Here we report the genomic details of two new reference Photorhabdus species. By then conducting genomic comparisons across the genus, we show that there are several highly conserved biosynthetic gene clusters. These clusters produce a range of bioactive small molecules that support the pathogenic phase of the integral relationship that Photorhabdus maintain with nematodes. Conclusions Photorhabdus contain several genetic loci that allow them to become specialist insect pathogens by efficiently evading insect immune responses and killing the insect host. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2862-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nicholas J Tobias
- Fachbereich Biowissenschaften, Merck Stiftungsprofessur für Molekulare Biotechnologie, Goethe Universität Frankfurt, Frankfurt am Main, Germany
| | - Bagdevi Mishra
- Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, 60325, Frankfurt am Main, Germany.,Fachbereich Biowissenschaften, Institut für Ökologie, Evolution und Diversität, Goethe Universität Frankfurt, Max-von-Laue-Str. 13, 60438, Frankfurt am Main, Germany
| | - Deepak K Gupta
- Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, 60325, Frankfurt am Main, Germany.,Fachbereich Biowissenschaften, Institut für Ökologie, Evolution und Diversität, Goethe Universität Frankfurt, Max-von-Laue-Str. 13, 60438, Frankfurt am Main, Germany
| | - Rahul Sharma
- Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, 60325, Frankfurt am Main, Germany
| | - Marco Thines
- Biodiversity and Climate Research Centre (BiK-F), Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, 60325, Frankfurt am Main, Germany.,Fachbereich Biowissenschaften, Institut für Ökologie, Evolution und Diversität, Goethe Universität Frankfurt, Max-von-Laue-Str. 13, 60438, Frankfurt am Main, Germany
| | - Timothy P Stinear
- Department of Microbiology and Immunology, University of Melbourne, at the Doherty Institute for Infection and Immunity, Parkville, VIC, 3010, Australia
| | - Helge B Bode
- Fachbereich Biowissenschaften, Merck Stiftungsprofessur für Molekulare Biotechnologie, Goethe Universität Frankfurt, Frankfurt am Main, Germany. .,Buchmann Institute for Molecular Life Sciences (BMLS), Goethe Universität Frankfurt, Frankfurt am Main, Germany.
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18
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Ren Y, Pan H, Pan B, Bu W. Identification and functional characterization of three TLR signaling pathway genes in Cyclina sinensis. FISH & SHELLFISH IMMUNOLOGY 2016; 50:150-159. [PMID: 26804650 DOI: 10.1016/j.fsi.2016.01.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 01/16/2016] [Accepted: 01/20/2016] [Indexed: 06/05/2023]
Abstract
Toll-like receptors (TLRs) are an ancient family of pattern recognition receptors that play a critical role in initiating and activating the innate immune system. In this study, we identified two TLR genes (CsTLR4 and CsTLR13) and the MyD88 (CsMyD88) gene using a transcriptome library from Cyclina sinensis. The sequence features and mRNA expression profiles of the genes were characterized, and their functions in the immune response were investigated to validate the TLR signaling pathway and its potential role in immune defense. The expression patterns of CsTLR4, CsTLR13 and CsMyD88 were detected in all the tissues examined from healthy clams and were primarily expressed in the hemocytes (P < 0.05), as shown by real-time PCR. Upon challenge with Vibrio anguillarum and Micrococcus luteus, they were significantly increased in hemocytes (P < 0.01), whereas only CsTLR13 and CsMyD88 were up-regulated (P < 0.01) by poly (I:C) challenge. In addition, the mRNA expression level of CsC-LYZ and CsAMP was down-regulated at 72 h (P < 0.01) after injection with CsMyD88 RNAi. These findings might be valuable for understanding the innate immune signaling pathways of C. sinensis and enabling future studies on host-pathogen interactions.
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Affiliation(s)
- Yipeng Ren
- Tianjin Key Laboratory of Animal and Plant Resistance, School of Life Sciences, Tianjin Normal University, Tianjin, 300387, PR China; Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, 300071, PR China
| | - Heting Pan
- Library of Tianjin Medical University, Tianjin, 300070, PR China
| | - Baoping Pan
- Tianjin Key Laboratory of Animal and Plant Resistance, School of Life Sciences, Tianjin Normal University, Tianjin, 300387, PR China.
| | - Wenjun Bu
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, 300071, PR China
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19
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Loskill P, Pereira PM, Jung P, Bischoff M, Herrmann M, Pinho MG, Jacobs K. Reduction of the peptidoglycan crosslinking causes a decrease in stiffness of the Staphylococcus aureus cell envelope. Biophys J 2015; 107:1082-1089. [PMID: 25185544 DOI: 10.1016/j.bpj.2014.07.029] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 06/30/2014] [Accepted: 07/15/2014] [Indexed: 11/28/2022] Open
Abstract
We have used atomic-force microscopy (AFM) to probe the effect of peptidoglycan crosslinking reduction on the elasticity of the Staphylococcus aureus cell wall, which is of particular interest as a target for antimicrobial chemotherapy. Penicillin-binding protein 4 (PBP4) is a nonessential transpeptidase, required for the high levels of peptidoglycan crosslinking characteristic of S. aureus. Importantly, this protein is essential for β-lactam resistance in community-acquired, methicillin-resistant S. aureus (MRSA) strains but not in hospital-acquired MRSA strains. Using AFM in a new mode for recording force/distance curves, we observed that the absence of PBP4, and the concomitant reduction of the peptidoglycan crosslinking, resulted in a reduction in stiffness of the S. aureus cell wall. Importantly, the reduction in cell wall stiffness in the absence of PBP4 was observed both in community-acquired and hospital-acquired MRSA strains, indicating that high levels of peptidoglycan crosslinking modulate the overall structure and mechanical properties of the S. aureus cell envelope in both types of clinically relevant strains. Additionally, we were able to show that the applied method enables the separation of cell wall properties and turgor pressure.
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Affiliation(s)
- Peter Loskill
- Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Pedro M Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Philipp Jung
- Institute of Medical Microbiology and Hygiene, Saarland University, Homburg/Saar, Germany
| | - Markus Bischoff
- Institute of Medical Microbiology and Hygiene, Saarland University, Homburg/Saar, Germany
| | - Mathias Herrmann
- Institute of Medical Microbiology and Hygiene, Saarland University, Homburg/Saar, Germany
| | - Mariana G Pinho
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
| | - Karin Jacobs
- Experimental Physics, Saarland University, Saarbrücken, Germany.
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20
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Carvalho F, Atilano ML, Pombinho R, Covas G, Gallo RL, Filipe SR, Sousa S, Cabanes D. L-Rhamnosylation of Listeria monocytogenes Wall Teichoic Acids Promotes Resistance to Antimicrobial Peptides by Delaying Interaction with the Membrane. PLoS Pathog 2015; 11:e1004919. [PMID: 26001194 PMCID: PMC4441387 DOI: 10.1371/journal.ppat.1004919] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 04/27/2015] [Indexed: 11/29/2022] Open
Abstract
Listeria monocytogenes is an opportunistic Gram-positive bacterial pathogen responsible for listeriosis, a human foodborne disease. Its cell wall is densely decorated with wall teichoic acids (WTAs), a class of anionic glycopolymers that play key roles in bacterial physiology, including protection against the activity of antimicrobial peptides (AMPs). In other Gram-positive pathogens, WTA modification by amine-containing groups such as D-alanine was largely correlated with resistance to AMPs. However, in L. monocytogenes, where WTA modification is achieved solely via glycosylation, WTA-associated mechanisms of AMP resistance were unknown. Here, we show that the L-rhamnosylation of L. monocytogenes WTAs relies not only on the rmlACBD locus, which encodes the biosynthetic pathway for L-rhamnose, but also on rmlT encoding a putative rhamnosyltransferase. We demonstrate that this WTA tailoring mechanism promotes resistance to AMPs, unveiling a novel link between WTA glycosylation and bacterial resistance to host defense peptides. Using in vitro binding assays, fluorescence-based techniques and electron microscopy, we show that the presence of L-rhamnosylated WTAs at the surface of L. monocytogenes delays the crossing of the cell wall by AMPs and postpones their contact with the listerial membrane. We propose that WTA L-rhamnosylation promotes L. monocytogenes survival by decreasing the cell wall permeability to AMPs, thus hindering their access and detrimental interaction with the plasma membrane. Strikingly, we reveal a key contribution of WTA L-rhamnosylation for L. monocytogenes virulence in a mouse model of infection. Listeria monocytogenes is a foodborne bacterial pathogen that preferentially infects immunocompromised hosts, eliciting a severe and often lethal disease. In humans, clinical manifestations range from asymptomatic intestinal carriage and gastroenteritis to harsher systemic states of the disease such as sepsis, meningitis or encephalitis, and fetal infections. The surface of L. monocytogenes is decorated with wall teichoic acids (WTAs), a class of carbohydrate-based polymers that contributes to cell surface-related events with implications in physiological processes, such as bacterial division or resistance to antimicrobial peptides (AMPs). The addition of other molecules to the backbone of WTAs modulates their chemical properties and consequently their functionality. In this context, we studied the role of WTA tailoring mechanisms in L. monocytogenes, whose WTAs are strictly decorated with monosaccharides. For the first time, we link WTA glycosylation with AMP resistance by showing that the decoration of L. monocytogenes WTAs with l-rhamnose confers resistance to host defense peptides. We suggest that this resistance is based on changes in the permeability of the cell wall that delay its crossing by AMPs and therefore promote the protection of the bacterial membrane integrity. Importantly, we also demonstrate the significance of this WTA modification in L. monocytogenes virulence.
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Affiliation(s)
- Filipe Carvalho
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular, Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Magda L Atilano
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Rita Pombinho
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular, Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Gonçalo Covas
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Richard L Gallo
- Division of Dermatology, Department of Medicine, University of California San Diego, San Diego, California, United States of America
| | - Sérgio R Filipe
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Sandra Sousa
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Didier Cabanes
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Group of Molecular Microbiology, Instituto de Biologia Molecular e Celular, Porto, Portugal
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21
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Reed P, Atilano ML, Alves R, Hoiczyk E, Sher X, Reichmann NT, Pereira PM, Roemer T, Filipe SR, Pereira-Leal JB, Ligoxygakis P, Pinho MG. Staphylococcus aureus Survives with a Minimal Peptidoglycan Synthesis Machine but Sacrifices Virulence and Antibiotic Resistance. PLoS Pathog 2015; 11:e1004891. [PMID: 25951442 PMCID: PMC4423922 DOI: 10.1371/journal.ppat.1004891] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 04/17/2015] [Indexed: 11/19/2022] Open
Abstract
Many important cellular processes are performed by molecular machines, composed of multiple proteins that physically interact to execute biological functions. An example is the bacterial peptidoglycan (PG) synthesis machine, responsible for the synthesis of the main component of the cell wall and the target of many contemporary antibiotics. One approach for the identification of essential components of a cellular machine involves the determination of its minimal protein composition. Staphylococcus aureus is a Gram-positive pathogen, renowned for its resistance to many commonly used antibiotics and prevalence in hospitals. Its genome encodes a low number of proteins with PG synthesis activity (9 proteins), when compared to other model organisms, and is therefore a good model for the study of a minimal PG synthesis machine. We deleted seven of the nine genes encoding PG synthesis enzymes from the S. aureus genome without affecting normal growth or cell morphology, generating a strain capable of PG biosynthesis catalyzed only by two penicillin-binding proteins, PBP1 and the bi-functional PBP2. However, multiple PBPs are important in clinically relevant environments, as bacteria with a minimal PG synthesis machinery became highly susceptible to cell wall-targeting antibiotics, host lytic enzymes and displayed impaired virulence in a Drosophila infection model which is dependent on the presence of specific peptidoglycan receptor proteins, namely PGRP-SA. The fact that S. aureus can grow and divide with only two active PG synthesizing enzymes shows that most of these enzymes are redundant in vitro and identifies the minimal PG synthesis machinery of S. aureus. However a complex molecular machine is important in environments other than in vitro growth as the expendable PG synthesis enzymes play an important role in the pathogenicity and antibiotic resistance of S. aureus. Peptidoglycan forms the stress-bearing sacculus that prevents lysis of bacteria due to turgor pressure. The integrity of peptidoglycan is therefore essential for bacterial survival and its synthesis is the target of many important antibiotics, such as penicillin. The final steps of peptidoglycan synthesis are catalyzed by penicillin-binding proteins, enzymes that are proposed to work in multi-enzyme complexes. We show that seven of the nine genes encoding peptidoglycan synthesis enzymes can be deleted from the Staphylococcus aureus genome without affecting normal growth and cell morphology in vitro, identifying the minimal peptidoglycan synthesis machinery of this organism. Identification of minimal machineries is key for synthetic biology efforts towards the design of systems with reduced complexity. However, the non-essential peptidoglycan synthetic proteins are important for survival of S. aureus in more challenging environments, such as in the presence of antibiotics that target cell wall synthesis or within the host, as shown by the inability of the mutant strain to establish a successful infection and kill Drosophila flies.
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Affiliation(s)
- Patricia Reed
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Magda L. Atilano
- Laboratory of Bacterial Cell Surface and Pathogenesis, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- Laboratory of Genes and Development, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Renato Alves
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Egbert Hoiczyk
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- The University of Sheffield, Department of Molecular Biology and Biotechnology, Western Bank, Sheffield, United Kingdom
| | - Xinwei Sher
- Merck Research Laboratories IT, Boston, Massachusetts, United States of America
| | - Nathalie T. Reichmann
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Pedro M. Pereira
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Terry Roemer
- Infectious Disease Research, Merck Research Laboratories, Kenilworth, New Jersey, United States of America
| | - Sérgio R. Filipe
- Laboratory of Bacterial Cell Surface and Pathogenesis, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | | | - Petros Ligoxygakis
- Laboratory of Genes and Development, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Mariana G. Pinho
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- * E-mail:
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22
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Stokes BA, Yadav S, Shokal U, Smith LC, Eleftherianos I. Bacterial and fungal pattern recognition receptors in homologous innate signaling pathways of insects and mammals. Front Microbiol 2015; 6:19. [PMID: 25674081 PMCID: PMC4309185 DOI: 10.3389/fmicb.2015.00019] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 01/07/2015] [Indexed: 12/12/2022] Open
Abstract
In response to bacterial and fungal infections in insects and mammals, distinct families of innate immune pattern recognition receptors (PRRs) initiate highly complex intracellular signaling cascades. Those cascades induce a variety of immune functions that restrain the spread of microbes in the host. Insect and mammalian innate immune receptors include molecules that recognize conserved microbial molecular patterns. Innate immune recognition leads to the recruitment of adaptor molecules forming multi-protein complexes that include kinases, transcription factors, and other regulatory molecules. Innate immune signaling cascades induce the expression of genes encoding antimicrobial peptides and other key factors that mount and regulate the immune response against microbial challenge. In this review, we summarize our current understanding of the bacterial and fungal PRRs for homologous innate signaling pathways of insects and mammals in an effort to provide a framework for future studies.
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Affiliation(s)
- Bethany A Stokes
- Insect Infection and Immunity Laboratory, Department of Biological Sciences, The George Washington University Washington, DC, USA
| | - Shruti Yadav
- Insect Infection and Immunity Laboratory, Department of Biological Sciences, The George Washington University Washington, DC, USA
| | - Upasana Shokal
- Insect Infection and Immunity Laboratory, Department of Biological Sciences, The George Washington University Washington, DC, USA
| | - L C Smith
- Insect Infection and Immunity Laboratory, Department of Biological Sciences, The George Washington University Washington, DC, USA
| | - Ioannis Eleftherianos
- Insect Infection and Immunity Laboratory, Department of Biological Sciences, The George Washington University Washington, DC, USA
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23
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Ishii K, Hamamoto H, Sekimizu K. Paralytic peptide: an insect cytokine that mediates innate immunity. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2015; 88:18-30. [PMID: 25521626 DOI: 10.1002/arch.21215] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Host animals combat invading pathogens by activating various immune responses. Modulation of the immune pathways by cytokines is critical for efficient pathogen elimination. Insects and mammals possess common innate immune systems, and individual immune pathways have been intensively studied over the last two decades. Relatively less attention, however, has been focused on the functions of cytokines in insect innate immunity. Here, we summarize our recent findings from studies of the insect cytokine, paralytic peptide, in the silkworm Bombyx mori. The content of this report was presented at the First Asian Invertebrate Immunity Symposium. Acute activation of paralytic peptide occurs via proteolysis after stimulation with the cell wall components of pathogens, leading to the induction of a wide range of cellular and humoral immune responses. The pathogenic bacterium Serratia marcescens suppresses paralytic peptide-dependent immune activation, which impairs host resistance. Studies of insect cytokines will broaden our understanding of the basic mechanisms underlying the interaction between host innate immunity and pathogenic agents.
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Affiliation(s)
- Kenichi Ishii
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
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24
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Liu X, Grabherr HM, Willmann R, Kolb D, Brunner F, Bertsche U, Kühner D, Franz-Wachtel M, Amin B, Felix G, Ongena M, Nürnberger T, Gust AA. Host-induced bacterial cell wall decomposition mediates pattern-triggered immunity in Arabidopsis. eLife 2014; 3:e01990. [PMID: 24957336 PMCID: PMC4103680 DOI: 10.7554/elife.01990] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 06/20/2014] [Indexed: 12/22/2022] Open
Abstract
Peptidoglycans (PGNs) are immunogenic bacterial surface patterns that trigger immune activation in metazoans and plants. It is generally unknown how complex bacterial structures such as PGNs are perceived by plant pattern recognition receptors (PRRs) and whether host hydrolytic activities facilitate decomposition of bacterial matrices and generation of soluble PRR ligands. Here we show that Arabidopsis thaliana, upon bacterial infection or exposure to microbial patterns, produces a metazoan lysozyme-like hydrolase (lysozyme 1, LYS1). LYS1 activity releases soluble PGN fragments from insoluble bacterial cell walls and cleavage products are able to trigger responses typically associated with plant immunity. Importantly, LYS1 mutant genotypes exhibit super-susceptibility to bacterial infections similar to that observed on PGN receptor mutants. We propose that plants employ hydrolytic activities for the decomposition of complex bacterial structures, and that soluble pattern generation might aid PRR-mediated immune activation in cell layers adjacent to infection sites.
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Affiliation(s)
- Xiaokun Liu
- Department of Plant Biochemistry, Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Heini M Grabherr
- Department of Plant Biochemistry, Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Roland Willmann
- Department of Plant Biochemistry, Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Dagmar Kolb
- Department of Plant Biochemistry, Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Frédéric Brunner
- Department of Plant Biochemistry, Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Ute Bertsche
- Department of Microbial Genetics, University of Tübingen, Tübingen, Germany
| | - Daniel Kühner
- Department of Microbial Genetics, University of Tübingen, Tübingen, Germany
| | | | - Bushra Amin
- Medical and Natural Sciences Research Centre, University of Tübingen, Tübingen, Germany
| | - Georg Felix
- Department of Plant Biochemistry, Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Marc Ongena
- Wallon Centre for Industrial Biology, University of Liege-Gembloux Agro-Bio Tech, Gembloux, Belgium
| | - Thorsten Nürnberger
- Department of Plant Biochemistry, Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Andrea A Gust
- Department of Plant Biochemistry, Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
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25
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Kuo TH, Williams JA. Increased sleep promotes survival during a bacterial infection in Drosophila. Sleep 2014; 37:1077-86, 1086A-1086D. [PMID: 24882902 DOI: 10.5665/sleep.3764] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
STUDY OBJECTIVES The relationship between sleep and immune function is not well understood at a functional or molecular level. We therefore used a genetic approach in Drosophila to manipulate sleep and evaluated effects on the ability of flies to fight bacterial infection. SETTING Laboratory. PARTICIPANTS Drosophila melanogaster. METHODS AND RESULTS We used a genetic approach to transiently alter neuronal excitability in the mushroom body, a region in the central brain that is known to regulate sleep. Flies with increased sleep for up to two days prior to a bacterial infection showed increased resistance to the infection and improved survival. These flies also had increased expression levels of a subset of anti-microbial peptide mRNA prior to infection, as well as increased NFκB activity during infection as indicated by in vivo luciferase reporter activity. In contrast, flies that experienced reduced sleep for up to two days prior to infection had no effect on survival or on NFκB activity during infection. However, flies with reduced sleep showed an altered defense mechanism, such that resistance to infection was increased, but at the expense of reduced tolerance. This effect was dependent on environmental condition. CONCLUSIONS Increasing sleep enhanced activity of an NFκB transcription factor, increased resistance to infection, and strongly promoted survival. Together, these findings support the hypothesis that sleep is beneficial to the host by maintaining a robust immune system.
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Affiliation(s)
- Tzu-Hsing Kuo
- Center for Sleep and Circadian Neurobiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | - Julie A Williams
- Center for Sleep and Circadian Neurobiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
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26
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Atilano ML, Pereira PM, Vaz F, Catalão MJ, Reed P, Grilo IR, Sobral RG, Ligoxygakis P, Pinho MG, Filipe SR. Bacterial autolysins trim cell surface peptidoglycan to prevent detection by the Drosophila innate immune system. eLife 2014; 3:e02277. [PMID: 24692449 PMCID: PMC3971415 DOI: 10.7554/elife.02277] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Bacteria have to avoid recognition by the host immune system in order to establish a successful infection. Peptidoglycan, the principal constituent of virtually all bacterial surfaces, is a specific molecular signature recognized by dedicated host receptors, present in animals and plants, which trigger an immune response. Here we report that autolysins from Gram-positive pathogenic bacteria, enzymes capable of hydrolyzing peptidoglycan, have a major role in concealing this inflammatory molecule from Drosophila peptidoglycan recognition proteins (PGRPs). We show that autolysins trim the outermost peptidoglycan fragments and that in their absence bacterial virulence is impaired, as PGRPs can directly recognize leftover peptidoglycan extending beyond the external layers of bacterial proteins and polysaccharides. The activity of autolysins is not restricted to the producer cells but can also alter the surface of neighboring bacteria, facilitating the survival of the entire population in the infected host. DOI:http://dx.doi.org/10.7554/eLife.02277.001 While most bacteria are harmless, some can cause diseases as varied as food poisoning and meningitis, so our immune system has developed various ways of detecting and eliminating bacteria and other pathogens. Receptor proteins belonging to the immune system detect molecules that give away the presence of the bacteria and trigger an immune response targeted at the invading pathogen. Peptidoglycan is one telltale molecule that betrays the presence of bacteria. Peptidoglycan is found in the bacterial cell wall, and for many years it was assumed that the immune system detected stray fragments of peptidoglycan that were accidentally shed by the bacteria. However, it was later shown that the immune system could, under certain conditions, detect peptidoglycan when it is still part of the cell wall. This raised an interesting question: do bacteria use other methods to stop peptidoglycan being detected by the immune system? Now, Atilano, Pereira et al. have found that enzymes called autolysins can conceal bacteria from the receptor proteins that detect peptidoglycan. These enzymes are needed to break the bonds within the peptidoglycan present in the rigid bacterial cell wall to allow the bacteria to grow and divide. ‘Knocking out’ the genes for autolysins allowed the receptor proteins from the fruit fly, Drosophila, to bind to the bacteria; however, the mutant bacteria were able to evade the immune system after they had been treated with the purified enzymes. Atilano, Pereira et al. suggest that the autolysins trim the exposed ends of the peptidoglycan molecules on the surface of the cell wall, which could otherwise be detected by the host. The experiments also show that bacterial pathogens—including a strain of MRSA—with mutations that knock out autolysin activity trigger a stronger immune response in fruit flies, and are therefore less able to infect this host. Autolysins also help to conceal Streptococcus pneumoniae—a bacterial pathogen that is a common cause of pneumonia and infant deaths in developing countries—from detection by fruit flies. The findings of Atilano, Pereira et al. highlight how bacteria employ a number of ways to evade detection. If similar behavior is observed when bacteria infect humans, autolysins could represent a new drug target for the treatment of bacterial diseases. DOI:http://dx.doi.org/10.7554/eLife.02277.002
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Affiliation(s)
- Magda Luciana Atilano
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal.,Genes and Development Laboratory, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Pedro Matos Pereira
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Filipa Vaz
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Maria João Catalão
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Patricia Reed
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Inês Ramos Grilo
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Rita Gonçalves Sobral
- Departamento de Ciências da Vida, Centro de Recursos Microbiologicos (CREM), Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Petros Ligoxygakis
- Genes and Development Laboratory, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Mariana Gomes Pinho
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Sérgio Raposo Filipe
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
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27
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Kurata S. Peptidoglycan recognition proteins in Drosophila immunity. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 42:36-41. [PMID: 23796791 PMCID: PMC3808481 DOI: 10.1016/j.dci.2013.06.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 06/11/2013] [Accepted: 06/11/2013] [Indexed: 05/13/2023]
Abstract
Innate immunity is the front line of self-defense against infectious non-self in vertebrates and invertebrates. The innate immune system is mediated by germ-line encoding pattern recognition molecules (pathogen sensors) that recognize conserved molecular patterns present in the pathogens but absent in the host. Peptidoglycans (PGN) are essential cell wall components of almost all bacteria, except mycoplasma lacking a cell wall, which provides the host immune system an advantage for detecting invading bacteria. Several families of pattern recognition molecules that detect PGN and PGN-derived compounds have been indentified, and the role of PGRP family members in host defense is relatively well-characterized in Drosophila. This review focuses on the role of PGRP family members in the recognition of invading bacteria and the activation and modulation of immune responses in Drosophila.
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Affiliation(s)
- Shoichiro Kurata
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan.
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28
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Kounatidis I, Ligoxygakis P. Drosophila as a model system to unravel the layers of innate immunity to infection. Open Biol 2013; 2:120075. [PMID: 22724070 PMCID: PMC3376734 DOI: 10.1098/rsob.120075] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 04/25/2012] [Indexed: 12/11/2022] Open
Abstract
Innate immunity relies entirely upon germ-line encoded receptors, signalling components and effector molecules for the recognition and elimination of invading pathogens. The fruit fly Drosophila melanogaster with its powerful collection of genetic and genomic tools has been the model of choice to develop ideas about innate immunity and host–pathogen interactions. Here, we review current research in the field, encompassing all layers of defence from the role of the microbiota to systemic immune activation, and attempt to speculate on future directions and open questions.
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Affiliation(s)
- Ilias Kounatidis
- Laboratory of Genes and Development, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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29
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Desmarais SM, De Pedro MA, Cava F, Huang KC. Peptidoglycan at its peaks: how chromatographic analyses can reveal bacterial cell wall structure and assembly. Mol Microbiol 2013; 89:1-13. [PMID: 23679048 DOI: 10.1111/mmi.12266] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2013] [Indexed: 02/02/2023]
Abstract
The peptidoglycan (PG) cell wall is a unique macromolecule responsible for both shape determination and cellular integrity under osmotic stress in virtually all bacteria. A quantitative understanding of the relationships between PG architecture, morphogenesis, immune system activation and pathogenesis can provide molecular-scale insights into the function of proteins involved in cell wall synthesis and cell growth. High-performance liquid chromatography (HPLC) has played an important role in our understanding of the structural and chemical complexity of the cell wall by providing an analytical method to quantify differences in chemical composition. Here, we present a primer on the basic chemical features of wall structure that can be revealed through HPLC, along with a description of the applications of HPLC PG analyses for interpreting the effects of genetic and chemical perturbations to a variety of bacterial species in different environments. We describe the physical consequences of different PG compositions on cell shape, and review complementary experimental and computational methodologies for PG analysis. Finally, we present a partial list of future targets of development for HPLC and related techniques.
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30
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Thioridazine induces major changes in global gene expression and cell wall composition in methicillin-resistant Staphylococcus aureus USA300. PLoS One 2013; 8:e64518. [PMID: 23691239 PMCID: PMC3656896 DOI: 10.1371/journal.pone.0064518] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/15/2013] [Indexed: 01/24/2023] Open
Abstract
Subinhibitory concentrations of the neuroleptic drug thioridazine (TDZ) are well-known to enhance the killing of methicillin-resistant Staphylococcus aureus (MRSA) by β-lactam antibiotics, however, the mechanism underlying the synergy between TDZ and β-lactams is not fully understood. In the present study, we have examined the effect of a subinhibitory concentration of TDZ on antimicrobial resistance, the global transcriptome, and the cell wall composition of MRSA USA300. We show that TDZ is able to sensitize the bacteria to several classes of antimicrobials targeting the late stages of peptidoglycan (PGN) synthesis. Furthermore, our microarray analysis demonstrates that TDZ modulates the expression of genes encoding membrane and surface proteins, transporters, and enzymes involved in amino acid biosynthesis. Interestingly, resemblance between the transcriptional profile of TDZ treatment and the transcriptomic response of S. aureus to known inhibitors of cell wall synthesis suggests that TDZ disturbs PGN biosynthesis at a stage that precedes transpeptidation by penicillin-binding proteins (PBPs). In support of this notion, dramatic changes in the muropeptide profile of USA300 were observed following growth in the presence of TDZ, indicating that TDZ can interfere with the formation of the pentaglycine branches. Strikingly, the addition of glycine to the growth medium relieved the effect of TDZ on the muropeptide profile. Furthermore, exogenous glycine offered a modest protective effect against TDZ-induced β-lactam sensitivity. We propose that TDZ exposure leads to a shortage of intracellular amino acids, including glycine, which is required for the production of normal PGN precursors with pentaglycine branches, the correct substrate of S. aureus PBPs. Collectively, this work demonstrates that TDZ has a major impact on the cell wall biosynthesis pathway in S. aureus and provides new insights into how MRSA may be sensitized towards β-lactam antibiotics.
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31
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Farha MA, Leung A, Sewell EW, D’Elia MA, Allison SE, Ejim L, Pereira PM, Pinho MG, Wright GD, Brown ED. Inhibition of WTA synthesis blocks the cooperative action of PBPs and sensitizes MRSA to β-lactams. ACS Chem Biol 2013; 8:226-33. [PMID: 23062620 PMCID: PMC3552485 DOI: 10.1021/cb300413m] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Rising drug resistance is limiting treatment options
for infections
by methicillin-resistant Staphylococcus aureus (MRSA).
Herein we provide new evidence that wall teichoic acid (WTA) biogenesis
is a remarkable antibacterial target with the capacity to destabilize
the cooperative action of penicillin-binding proteins (PBPs) that
underlie β-lactam resistance in MRSA. Deletion of gene tarO, encoding the first step of WTA synthesis, resulted
in the restoration of sensitivity of MRSA to a unique profile of β-lactam
antibiotics with a known selectivity for penicillin binding protein
2 (PBP2). Of these, cefuroxime was used as a probe to screen for previously
approved drugs with a cryptic capacity to potentiate its activity
against MRSA. Ticlopidine, the antiplatelet drug Ticlid, strongly
potentiated cefuroxime, and this synergy was abolished in strains
lacking tarO. The combination was also effective
in a Galleria mellonella model of infection. Using
both genetic and biochemical strategies, we determined the molecular
target of ticlopidine as the N-acetylglucosamine-1-phosphate
transferase encoded in gene tarO and provide evidence
that WTA biogenesis represents an Achilles heel supporting the cooperative
function of PBP2 and PBP4 in creating highly cross-linked muropeptides
in the peptidoglycan of S. aureus. This approach
represents a new paradigm to tackle MRSA infection.
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Affiliation(s)
- Maya A. Farha
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Alexander Leung
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Edward W. Sewell
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Michael A. D’Elia
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Sarah E. Allison
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Linda Ejim
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Pedro M. Pereira
- Laboratory of Bacterial Cell
Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - Mariana G. Pinho
- Laboratory of Bacterial Cell
Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - Gerard D. Wright
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Eric D. Brown
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
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32
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Roth A, Reichmann P, Hakenbeck R. The capsule of Streptococcus pneumoniae contributes to virulence in the insect model Manduca sexta. J Mol Microbiol Biotechnol 2012; 22:326-34. [PMID: 23221622 DOI: 10.1159/000345327] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The polysaccharide capsule of Streptococcus pneumoniae is one of the most important virulence factors responsible for human infections and in mouse infection models as well. Larvae of Manduca sexta were used as an alternative animal model in order to test the impact of the pneumococcal capsule on virulence in the insect host. The unencapsulated S. pneumoniae strain R6 was able to cause disease and induce killing in the larvae, and similar results were obtained with related commensal species. However, using the same dose of S. pneumoniae, encapsulated strains including the type 2 D39 strain, the progenitor of R6, and genetically unrelated S. pneumoniae strains of serotype 2, 4, 6B, 23F and 19A, all had increased virulence potential compared to the R6 strain. Between 20 and 70% of the larvae were affected after 96 h compared to 12% observed with R6. Two type 6B S. pneumoniae strains were more virulent compared to the other strains. S. pneumoniae R6 transformants producing the type 6B capsule showed a similar elevated disease potential, confirming the contribution of the pneumococcal polysaccharide capsule to virulence in M. sexta.
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Affiliation(s)
- Angelika Roth
- Department of Microbiology, University of Kaiserslautern, Kaiserslautern, Germany.
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33
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Evolution of the βGRP/GNBP/β-1,3-glucanase family of insects. Immunogenetics 2012; 64:549-58. [DOI: 10.1007/s00251-012-0610-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 02/29/2012] [Indexed: 11/28/2022]
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Atilano ML, Yates J, Glittenberg M, Filipe SR, Ligoxygakis P. Wall teichoic acids of Staphylococcus aureus limit recognition by the drosophila peptidoglycan recognition protein-SA to promote pathogenicity. PLoS Pathog 2011; 7:e1002421. [PMID: 22144903 PMCID: PMC3228820 DOI: 10.1371/journal.ppat.1002421] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 10/20/2011] [Indexed: 12/15/2022] Open
Abstract
The cell wall of gram-positive bacteria is a complex network of surface proteins, capsular polysaccharides and wall teichoic acids (WTA) covalently linked to Peptidoglycan (PG). The absence of WTA has been associated with a reduced pathogenicity of Staphylococcus aureus (S. aureus). Here, we assessed whether this was due to increased detection of PG, an important target of innate immune receptors. Antibiotic-mediated or genetic inhibition of WTA production in S. aureus led to increased binding of the non-lytic PG Recognition Protein-SA (PGRP-SA), and this was associated with a reduction in host susceptibility to infection. Moreover, PGRP-SD, another innate sensor required to control wild type S. aureus infection, became redundant. Our data imply that by using WTA to limit access of innate immune receptors to PG, under-detected bacteria are able to establish an infection and ultimately overwhelm the host. We propose that different PGRPs work in concert to counter this strategy.
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Affiliation(s)
- Magda L. Atilano
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica/Universidade Nova de Lisboa, Oeiras, Portugal
| | - James Yates
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica/Universidade Nova de Lisboa, Oeiras, Portugal
| | - Marcus Glittenberg
- Genes and Development Laboratory, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Sergio R. Filipe
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica/Universidade Nova de Lisboa, Oeiras, Portugal
- * E-mail: (SF); (PL)
| | - Petros Ligoxygakis
- Genes and Development Laboratory, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail: (SF); (PL)
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35
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Kurata S. Fly immunity: recognition of pathogens and induction of immune responses. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 708:205-17. [PMID: 21528700 DOI: 10.1007/978-1-4419-8059-5_11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Despite the lack of adaptive immunity based on gene rearrangement such as that in higher vertebrates, flies are able to defend themselves from a wide array of pathogens using multiple innate immune responses whose molecular mechanisms are strikingly similar to those of the innate immune responses of other multicellular organisms, including humans. Invading pathogens passing through the epithelial barriers, the first line of self-defense, are detected by pattern recognition receptors that identify pathogen-associated molecular patterns in the hemolymph or on the immune cell surface and are eliminated by humoral and cellular responses. Some pathogens escape recognition and elimination in the hemolymphby invading the host cell cytoplasm. Some of these intracellular pathogens, however, such as Listeria monocytogenes, are identified by pattern recognition receptors in the cytoplasm and are eliminated by intracellular responses, including autophagy, an intracellular degradation system. Although some of these pattern recognition receptors are encoded in the germ-line as protein families, another type of receptor in the immunoglobulin-superfamily is extensively diversified by alternative splicing in somatic immune cells in Drosophila.
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Affiliation(s)
- Shoichiro Kurata
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
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36
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Li Y, Efferson CL, Ramesh R, Peoples GE, Hwu P, Ioannides CG. A peptidoglycan monomer with the glutamine to serine change and basic peptides bind in silico to TLR-2 (403-455). Cancer Immunol Immunother 2011; 60:515-24. [PMID: 21188584 PMCID: PMC11028711 DOI: 10.1007/s00262-010-0959-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Accepted: 12/08/2010] [Indexed: 12/30/2022]
Abstract
Bacterial cell wall polysaccharides, such as PGN, bind and activate TLR-2, NOD2 and PGRP on monocytes/macrophages and activate inflammation. We found that the peptides containing basic amino acids (cations) at N -terminus and tyrosine at C-terminus interfered with activating ability of PGN. This finding is significant because the ECD of TLR-2 in vivo encounters a large number of proteins or peptides. Some should bind ECD and "pre-form" TLR-2 to respond or not to its activators, although they cannot activate TLR-2 alone. TLR-2 is receptor for a large number of ligands, including lipopeptides and bacterial cell wall glycoproteins. A binding site for lipopeptides has been identified; however, a binding site for soluble or multimeric PGN has not been proposed. To identify the candidate binding sites of peptides and PGN on TLR-2, we modeled docking of peptides and of the PGN monomer (PGN-S-monomer) to extracellular domain (ECD-TLR-2) of the unbound TLR-2. Quantification, in silico, of free energy of binding (DG) identified 2 close sites for peptides and PGN. The PGN-S-monomer binding site is between amino acids TLR-2, 404-430 or more closely TLR-2, 417-428. The peptide-binding site is between amino acids TLR-2, 434-455. Molecular models show PGN-S-monomer inserts its N -acetyl-glucosamine (NAG) deep in the TLR-2 coil, while its terminal lysine interacts with inside (Glu(403)) and outside pocket (Tyr(378)). Peptides insert their two N -terminal arginines or their C-terminal tyrosines in the TLR-2 coil. PGN did not bind the lipopeptide-binding site in the TLR-2. It can bind the C-terminus, 572-586 (DG = 0.026 kcal), of "lipopeptide-bound" TLR-2. An additional, low-affinity PGN-binding site is TLR-2 (227-237). MTP, MDP, and lysine-less PGN bind to TLR-2, 87-113. This is the first report identifying candidate binding sites of monomer PGN and peptides on TLR-2. Experimental verification of our findings is needed to create synthetic adjuvant for vaccines. Such synthetic PGN can direct both adjuvant and cancer antigen to TLR-2.
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Affiliation(s)
- Yufeng Li
- Departments of Melanoma Medical Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 USA
- Departments of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, P.O. Box 304, Houston, TX 77030 USA
| | - Clay L. Efferson
- Departments of Gynecologic Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 USA
- Present Address: Merck Corporation, Boston, MA USA
| | - Rajagopal Ramesh
- Departments of Thoracic Surgery, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 USA
| | - George E. Peoples
- Department of Surgery, General Surgery Service, Brooke Army Medical Center, 3851 Roger Brooke Drive, Fort Sam, Houston, TX 78234 USA
| | - Patrick Hwu
- Departments of Melanoma Medical Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 USA
| | - Constantin G. Ioannides
- Departments of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, P.O. Box 304, Houston, TX 77030 USA
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37
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Liu H, Wu C, Matsuda Y, Kawabata SI, Lee BL, Söderhäll K, Söderhäll I. Peptidoglycan activation of the proPO-system without a peptidoglycan receptor protein (PGRP)? DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2011; 35:51-61. [PMID: 20713082 DOI: 10.1016/j.dci.2010.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 08/09/2010] [Accepted: 08/09/2010] [Indexed: 05/29/2023]
Abstract
Recognition of microbial polysaccharide by pattern recognition receptors triggers the prophenoloxidase (proPO) cascade, resulting in melanin synthesis and its deposition on the surface of invading pathogens. Several masquerade-like proteins and serine proteinase homologues have been shown to be involved in the proPO activation in insects. In this study, a novel serine proteinase homologue, Pl-SPH2, was found and isolated as a 30kDa protein from hemocytes of the freshwater crayfish, Pacifastacus leniusculus, by its binding property to a partially lysozyme digested or TCA-treated insoluble Lysine (Lys)-type peptidoglycan (PGN) and soluble polymeric Lys-type PGN. Two other proteins, the Pl-SPH1 and lipopolysaccharide- and β-1,3-glucan-binding protein (LGBP) were also found in the several different PGN-binding assays. However no PGRP homologue was detected. Neither was any putative PGRP found after searching available crustacean sequence databases. If RNA interference of Pl-SPH2, Pl-SPH1 or LGBP in the crayfish hematopoietic tissue cell culture was performed, it resulted in lower PO activity following activation of the proPO-system by soluble Lys-type PGN. Taken together, we report for the first time that Lys-type PGN is a trigger of proPO-system activation in a crustacean and that two Pl-SPHs are involved in this activation possibly by forming a complex with LGBP and without a PGRP.
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Affiliation(s)
- Haipeng Liu
- Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden
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38
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Zhang J, Yang L, Ang Z, Yoong SL, Tran TTT, Anand GS, Tan NS, Ho B, Ding JL. Secreted M-ficolin anchors onto monocyte transmembrane G protein-coupled receptor 43 and cross talks with plasma C-reactive protein to mediate immune signaling and regulate host defense. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2010; 185:6899-910. [PMID: 21037097 DOI: 10.4049/jimmunol.1001225] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Although transmembrane C-type lectins (CLs) are known to initiate immune signaling, the participation and mechanism of action of soluble CLs have remained enigmatic. In this study, we found that M-ficolin, a conserved soluble CL of monocyte origin, overcomes its lack of membrane-anchor domain by docking constitutively onto a monocyte transmembrane receptor, G protein-coupled receptor 43 (GPCR43), to form a pathogen sensor-cum-signal transducer. On encountering microbial invaders, the M-ficolin-GPCR43 complex activates the NF-κB cascade to upregulate IL-8 production. We showed that mild acidosis at the local site of infection induces conformational changes in the M-ficolin molecule, which provokes a strong interaction between the C-reactive protein (CRP) and the M-ficolin-GPCR43 complex. The collaboration among CRP-M-ficolin-GPCR43 under acidosis curtails IL-8 production thus preventing immune overactivation. Therefore, we propose that a soluble CL may become membrane-associated through interaction with a transmembrane protein, whereupon infection collaborates with other plasma protein to transduce the infection signal and regulate host defense. Our finding implies a possible mechanism whereby the host might expand its repertoire of immune recognition-cum-regulation tactics by promiscuous protein networking. Furthermore, our identification of the pH-sensitive interfaces of M-ficolin-CRP provides a powerful template for future design of potential immunomodulators.
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Affiliation(s)
- Jing Zhang
- Department of Biological Sciences, National University of Singapore, Singapore
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39
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Teichoic acids are temporal and spatial regulators of peptidoglycan cross-linking in Staphylococcus aureus. Proc Natl Acad Sci U S A 2010; 107:18991-6. [PMID: 20944066 DOI: 10.1073/pnas.1004304107] [Citation(s) in RCA: 193] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cell wall of Staphylococcus aureus is characterized by an extremely high degree of cross-linking within its peptidoglycan (PGN). Penicillin-binding protein 4 (PBP4) is required for the synthesis of this highly cross-linked peptidoglycan. We found that wall teichoic acids, glycopolymers attached to the peptidoglycan and important for virulence in Gram-positive bacteria, act as temporal and spatial regulators of PGN metabolism, controlling the level of cross-linking by regulating PBP4 localization. PBP4 normally localizes at the division septum, but in the absence of wall teichoic acids synthesis, it becomes dispersed throughout the entire cell membrane and is unable to function normally. As a consequence, the peptidoglycan of TagO null mutants, impaired in wall teichoic acid biosynthesis, has a decreased degree of cross-linking, which renders it more susceptible to the action of lysozyme, an enzyme produced by different host organisms as an initial defense against bacterial infection.
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40
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Ishii K, Hamamoto H, Imamura K, Adachi T, Shoji M, Nakayama K, Sekimizu K. Porphyromonas gingivalis peptidoglycans induce excessive activation of the innate immune system in silkworm larvae. J Biol Chem 2010; 285:33338-33347. [PMID: 20702417 DOI: 10.1074/jbc.m110.112987] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Porphyromonas gingivalis, a pathogen that causes inflammation in human periodontal tissue, killed silkworm (Bombyx mori, Lepidoptera) larvae when injected into the blood (hemolymph). Silkworm lethality was not rescued by antibiotic treatment, and heat-killed bacteria were also lethal. Heat-killed bacteria of mutant P. gingivalis strains lacking virulence factors also killed silkworms. Silkworms died after injection of peptidoglycans purified from P. gingivalis (pPG), and pPG toxicity was blocked by treatment with mutanolysin, a peptidoglycan-degrading enzyme. pPG induced silkworm hemolymph melanization at the same dose as that required to kill the animal. pPG injection increased caspase activity in silkworm tissues. pPG-induced silkworm death was delayed by injecting melanization-inhibiting reagents (a serine protease inhibitor and 1-phenyl-2-thiourea), antioxidants (N-acetyl-l-cysteine, glutathione, and catalase), and a caspase inhibitor (Ac-DEVD-CHO). Thus, pPG induces excessive activation of the innate immune response, which leads to the generation of reactive oxygen species and apoptotic cell death in the host tissue.
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Affiliation(s)
- Kenichi Ishii
- From the Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
| | - Hiroshi Hamamoto
- From the Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
| | - Katsutoshi Imamura
- From the Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
| | - Tatsuo Adachi
- From the Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
| | - Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8588, Japan
| | - Koji Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8588, Japan
| | - Kazuhisa Sekimizu
- From the Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan.
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41
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Affiliation(s)
- Jed F Fisher
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Hall, Notre Dame, Indiana 46556-5670, USA
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42
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Ryu JH, Ha EM, Lee WJ. Innate immunity and gut-microbe mutualism in Drosophila. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2010; 34:369-376. [PMID: 19958789 DOI: 10.1016/j.dci.2009.11.010] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 11/25/2009] [Accepted: 11/25/2009] [Indexed: 05/28/2023]
Abstract
Metazoan guts face a wide variety of microorganisms upon exposure to the environment, including beneficial symbionts, non-symbionts, food-borne microbes and life-threatening pathogens. Recent evidence has shown that the innate immunity of gut epithelia, such as anti-microbial peptide- and reactive oxygen species-based immune systems, actively participate in gut-microbe homeostasis by shaping the commensal community while efficiently eliminating unwanted bacteria. Therefore, elucidation of the regulatory mechanism by which gut innate immunity occurs at the molecular level will provide a novel perspective of gut-microbe mutualisms as well as of gut diseases caused by alterations in the innate immunity.
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Affiliation(s)
- Ji-Hwan Ryu
- Division of Life and Pharmaceutical Science, Department of Life Science, Department of Bioinspired Science, and National Creative Research Initiative Center for Symbiosystem, Ewha Woman's University, Seoul 120-750, South Korea
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43
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Kurata S. Extracellular and intracellular pathogen recognition by Drosophila PGRP-LE and PGRP-LC. Int Immunol 2010; 22:143-8. [PMID: 20089584 PMCID: PMC2829096 DOI: 10.1093/intimm/dxp128] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Accepted: 12/24/2009] [Indexed: 12/16/2022] Open
Abstract
Despite lacking the adaptive immunity that is found in higher vertebrates, insects are able to defend themselves from a large battery of pathogens by multiple innate immune responses using molecular mechanisms that are strikingly similar to the innate immune responses of other multicellular organisms, including humans. The fruit fly Drosophila melanogaster is therefore an excellent model organism for studying the basic principles of innate immunity using genetic and molecular biology techniques. In Drosophila, invading pathogens that pass through the epithelial barriers (a first line of self-defense) can encounter humoral and cellular responses that utilize pattern-recognition receptors to identify pathogen-associated molecular patterns in the hemolymph or on the immune cell surface. Some pathogens escape recognition and elimination in the hemolymph by invading the host cytoplasm. Some intracellular pathogens such as Listeria monocytogenes are, nevertheless, eliminated by immune reactions such as autophagy through intracellular identification by pattern-recognition receptors.
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Affiliation(s)
- Shoichiro Kurata
- Laboratory of Molecular Genetics, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
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44
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Kövér KE, Szilágyi L, Batta G, Uhrín D, Jiménez-Barbero J. Biomolecular Recognition by Oligosaccharides and Glycopeptides: The NMR Point of View. COMPREHENSIVE NATURAL PRODUCTS II 2010:197-246. [DOI: 10.1016/b978-008045382-8.00193-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
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45
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Schmidt O, Söderhäll K, Theopold U, Faye I. Role of adhesion in arthropod immune recognition. ANNUAL REVIEW OF ENTOMOLOGY 2010; 55:485-504. [PMID: 19743913 DOI: 10.1146/annurev.ento.54.110807.090618] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The recognition and inactivation of toxins and pathogens are mediated by a combination of cell-free and cellular mechanisms. A number of soluble and membrane-bound pattern recognition molecules interact with elicitors to become involved in both cell-free inactivation as well as cellular uptake reactions. Here we describe the possible recognition and effector function of key arthropod immune proteins, such as peroxinectin, hemolin, and hemomucin, as an outcome of changes in adhesiveness, which drive self-assembly reactions leading to cell-free coagulation and cellular uptake reactions. The fact that some of these proteins are essential for immune and developmental functions in some species, but are not found in closely related species, may point to the existence of multiprotein assemblies, which are conserved at the mechanistic level and can function with more than one combination of protein constituents.
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Affiliation(s)
- Otto Schmidt
- Insect Molecular Biology, University of Adelaide, Glen Osmond, SA 5064, Australia.
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46
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Ganesan S, Aggarwal K, Paquette N, Silverman N. NF-κB/Rel proteins and the humoral immune responses of Drosophila melanogaster. Curr Top Microbiol Immunol 2010; 349:25-60. [PMID: 20852987 DOI: 10.1007/82_2010_107] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Nuclear Factor-κB (NF-κB)/Rel transcription factors form an integral part of innate immune defenses and are conserved throughout the animal kingdom. Studying the function, mechanism of activation and regulation of these factors is crucial for understanding host responses to microbial infections. The fruit fly Drosophila melanogaster has proved to be a valuable model system to study these evolutionarily conserved NF-κB mediated immune responses. Drosophila combats pathogens through humoral and cellular immune responses. These humoral responses are well characterized and are marked by the robust production of a battery of anti-microbial peptides. Two NF-κB signaling pathways, the Toll and the IMD pathways, are responsible for the induction of these antimicrobial peptides. Signal transduction in these pathways is strikingly similar to that in mammalian TLR pathways. In this chapter, we discuss in detail the molecular mechanisms of microbial recognition, signal transduction and NF-κB regulation, in both the Toll and the IMD pathways. Similarities and differences relative to their mammalian counterparts are discussed, and recent advances in our understanding of the intricate regulatory networks in these NF-κB signaling pathways are also highlighted.
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Affiliation(s)
- Sandhya Ganesan
- Division of Infectious Diseases, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
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47
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Silverman N, Paquette N, Aggarwal K. Specificity and signaling in the Drosophila immune response. INVERTEBRATE SURVIVAL JOURNAL : ISJ 2009; 6:163-174. [PMID: 21625362 PMCID: PMC3101770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The Drosophila immune response is characterized by the rapid and robust production of a battery of antimicrobial peptides immediately following infection. The genes encoding these antimicrobial peptides are controlled by two NF-κB signaling pathways that respond to microbial infection. The IMD pathway is triggered by DAP-type peptidoglycan, from the cell wall of most Gram-negative and certain Gram-positive bacteria, and activates the NF-κB precursor protein Relish. The Toll pathway, on the other hand, is stimulated by lysine-type peptidoglycan from many Gram-positive bacteria, β 1,3 glucans from many fungi, as well as by microbial proteases. Toll signaling leads to the activation and nuclear translocation of DIF or Dorsal, two other NF-κB homologs. This review presents our current understanding of the molecular mechanisms involved in microbial recognition and signal transduction in these two innate immune pathways.
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Affiliation(s)
- N Silverman
- University of Massachusetts Medical School, Worcester, USA
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48
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Troll JV, Adin DM, Wier AM, Paquette N, Silverman N, Goldman WE, Stadermann FJ, Stabb EV, McFall-Ngai MJ. Peptidoglycan induces loss of a nuclear peptidoglycan recognition protein during host tissue development in a beneficial animal-bacterial symbiosis. Cell Microbiol 2009; 11:1114-27. [PMID: 19416268 DOI: 10.1111/j.1462-5822.2009.01315.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptidoglycan recognition proteins (PGRPs) are mediators of innate immunity and recently have been implicated in developmental regulation. To explore the interplay between these two roles, we characterized a PGRP in the host squid Euprymna scolopes (EsPGRP1) during colonization by the mutualistic bacterium Vibrio fischeri. Previous research on the squid-vibrio symbiosis had shown that, upon colonization of deep epithelium-lined crypts of the host light organ, symbiont-derived peptidoglycan monomers induce apoptosis-mediated regression of remote epithelial fields involved in the inoculation process. In this study, immunofluorescence microscopy revealed that EsPGRP1 localizes to the nuclei of epithelial cells, and symbiont colonization induces the loss of EsPGRP1 from apoptotic nuclei. The loss of nuclear EsPGRP1 occurred prior to DNA cleavage and breakdown of the nuclear membrane, but followed chromatin condensation, suggesting that it occurs during late-stage apoptosis. Experiments with purified peptidoglycan monomers and with V. fischeri mutants defective in peptidoglycan-monomer release provided evidence that these molecules trigger nuclear loss of EsPGRP1 and apoptosis. The demonstration of a nuclear PGRP is unprecedented, and the dynamics of EsPGRP1 during apoptosis provide a striking example of a connection between microbial recognition and developmental responses in the establishment of symbiosis.
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Affiliation(s)
- Joshua V Troll
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, 53706, USA
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Lessons from the fly: pattern recognition in Drosophila melanogaster. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 653:162-74. [PMID: 19799118 DOI: 10.1007/978-1-4419-0901-5_11] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Drosophila have a variety of innate immune strategies for defending itself from infection, including humoral and cell mediated responses to invading microorganisms. At the front lines of these responses, are a diverse group of pattern recognition receptors that recognize pathogen associated molecular patterns. These patterns include bacterial lipopolysaccharides, peptidoglycans, and fungal beta-1,3 glucans. Some of the receptors catalytically modify the pathogenic determinant, but all are responsible for directly facilitating a signaling event that results in an immune response. Some of these events require multiple pattern recognition receptors acting sequentially to activate a pathway. In some cases, a signaling pathway may be activated by a variety of different pathogens, through parallel receptors detecting different pathogenic determinants. In this chapter, we review what is known about pattern recognition receptors in Drosophila, and how those lessons may be applied towards a broader understanding of immunity.
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Wang L, Gilbert RJC, Atilano ML, Filipe SR, Gay NJ, Ligoxygakis P. Peptidoglycan recognition protein-SD provides versatility of receptor formation in Drosophila immunity. Proc Natl Acad Sci U S A 2008; 105:11881-6. [PMID: 18697931 PMCID: PMC2575254 DOI: 10.1073/pnas.0710092105] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Indexed: 12/11/2022] Open
Abstract
In Drosophila, the enzymatic activity of the glucan binding protein GNBP1 is needed to present Gram-positive peptidoglycan (PG) to peptidoglycan recognition protein SA (PGRP-SA). However, an additional PGRP (PGRP-SD) has been proposed to play a partially redundant role with GNBP1 and PGRP-SA. To reconcile the genetic results with events at the molecular level, we investigated how PGRP-SD participates in the sensing of Gram-positive bacteria. PGRP-SD enhanced the binding of GNBP1 to Gram-positive PG. PGRP-SD interacted with GNBP1 and enhanced the interaction between GNBP1 and PGRP-SA. A complex containing all three proteins could be detected in native gels in the presence of PG. In solution, addition of a highly purified PG fragment induced the occurrence not only of the ternary complex but also of dimeric subcomplexes. These results indicate that the interplay between the binding affinities of different PGRPs provides sufficient flexibility for the recognition of the highly diverse Gram-positive PG.
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Affiliation(s)
- Lihui Wang
- *Genetics Unit, Department of Biochemistry, South Parks Road, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Robert J. C. Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Magda L. Atilano
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal; and
| | - Sergio R. Filipe
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal; and
| | - Nicholas J. Gay
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Petros Ligoxygakis
- *Genetics Unit, Department of Biochemistry, South Parks Road, University of Oxford, Oxford OX1 3QU, United Kingdom
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