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Payen S, Giroux MC, Gisch N, Schombel U, Fittipaldi N, Segura M, Gottschalk M. Lipoteichoic acids influence cell shape and bacterial division of Streptococcus suis serotype 2, but play a limited role in the pathogenesis of the infection. Vet Res 2024; 55:34. [PMID: 38504299 PMCID: PMC10953176 DOI: 10.1186/s13567-024-01287-w] [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: 01/22/2024] [Accepted: 03/01/2024] [Indexed: 03/21/2024] Open
Abstract
Streptococcus suis serotype 2 is a major swine pathogen and a zoonotic agent, causing meningitis in both swine and humans, responsible for substantial economic losses to the swine industry worldwide. The pathogenesis of infection and the role of bacterial cell wall components in virulence have not been fully elucidated. Lipoproteins, peptidoglycan, as well as lipoteichoic acids (LTA) have all been proposed to contribute to virulence. In the present study, the role of the LTA in the pathogenesis of the infection was evaluated through the characterisation of a mutant of the S. suis serotype 2 strain P1/7 lacking the LtaS enzyme, which mediates the polymerization of the LTA poly-glycerolphosphate chain. The ltaS mutant was confirmed to completely lack LTA and displayed significant morphological defects. Although the bacterial growth of this mutant was not affected, further results showed that LTA is involved in maintaining S. suis bacterial fitness. However, its role in the pathogenesis of the infection appears limited. Indeed, LTA presence reduces self-agglutination, biofilm formation and even dendritic cell activation, which are important aspects of the pathogenesis of the infection caused by S. suis. In addition, it does not seem to play a critical role in virulence using a systemic mouse model of infection.
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Affiliation(s)
- Servane Payen
- Research Group On Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - Marie-Christine Giroux
- Research Group On Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Ursula Schombel
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Nahuel Fittipaldi
- Research Group On Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - Mariela Segura
- Research Group On Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, J2S 2M2, Canada
| | - Marcelo Gottschalk
- Research Group On Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, J2S 2M2, Canada.
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Bleuzé M, Lavoie JP, Bédard C, Gottschalk M, Segura M. Encapsulated Streptococcus suis impairs optimal neutrophil functions which are not rescued by priming with colony-stimulating factors. PLoS One 2024; 19:e0296844. [PMID: 38261585 PMCID: PMC10805302 DOI: 10.1371/journal.pone.0296844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 12/19/2023] [Indexed: 01/25/2024] Open
Abstract
The porcine pathogen and zoonotic agent Streptococcus suis induces an exacerbated inflammation in the infected hosts that leads to sepsis, meningitis, and sudden death. Several virulence factors were described for S. suis of which the capsular polysaccharide (CPS) conceals it from the immune system, and the suilysin exhibits cytotoxic activity. Although neutrophils are recruited rapidly upon S. suis infection, their microbicidal functions appear to be poorly activated against the bacteria. However, during disease, the inflammatory environment could promote neutrophil activation as mediators such as the granulocyte colony-stimulating factor granulocyte (G-CSF) and the granulocyte-macrophages colony-stimulating factor (GM-CSF) prime neutrophils and enhance their responsiveness to bacterial detection. Thus, we hypothesized that CPS and suilysin prevent an efficient activation of neutrophils by S. suis, but that G-CSF and GM-CSF rescue neutrophil activation, leading to S. suis elimination. We evaluated the functions of porcine neutrophils in vitro in response to S. suis and investigated the role of the CPS and suilysin on cell activation using isogenic mutants of the bacteria. We also studied the influence of G-CSF and GM-CSF on neutrophil response to S. suis by priming the cells with recombinant proteins. Our study confirmed that CPS prevents S. suis-induced activation of most neutrophil functions but participates in the release of neutrophil-extracellular traps (NETs). Priming with G-CSF did not influence cell activation, but GM-CSF strongly promote IL-8 release, indicating its involvement in immunomodulation. However, priming did not enhance microbicidal functions. Studying the interaction between S. suis and neutrophils-first responders in host defense-remains fundamental to understand the immunopathogenesis of the infection and to develop therapeutical strategies related to neutrophils' defense against this bacterium.
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Affiliation(s)
- Marêva Bleuzé
- Faculty of Veterinary Medicine, Research Group on Infectious Diseases in Production Animals (GREMIP) & Swine and Poultry Infectious Diseases Research Center (CRIPA), Université de Montréal, St-Hyacinthe, Quebec, Canada
| | - Jean-Pierre Lavoie
- Faculty of Veterinary Medicine, Department of Clinical Sciences, Université de Montréal, St-Hyacinthe, Quebec, Canada
| | - Christian Bédard
- Faculty of Veterinary Medicine, Department of Pathology and Microbiology, Université de Montréal, St-Hyacinthe, Quebec, Canada
| | - Marcelo Gottschalk
- Faculty of Veterinary Medicine, Research Group on Infectious Diseases in Production Animals (GREMIP) & Swine and Poultry Infectious Diseases Research Center (CRIPA), Université de Montréal, St-Hyacinthe, Quebec, Canada
| | - Mariela Segura
- Faculty of Veterinary Medicine, Research Group on Infectious Diseases in Production Animals (GREMIP) & Swine and Poultry Infectious Diseases Research Center (CRIPA), Université de Montréal, St-Hyacinthe, Quebec, Canada
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3
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Gussak A, Ferrando ML, Schrama M, van Baarlen P, Wells JM. Precision Genome Engineering in Streptococcus suis Based on a Broad-Host-Range Vector and CRISPR-Cas9 Technology. ACS Synth Biol 2023; 12:2546-2560. [PMID: 37602730 PMCID: PMC10510748 DOI: 10.1021/acssynbio.3c00110] [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: 02/18/2023] [Indexed: 08/22/2023]
Abstract
Streptococcussuis is an important zoonotic pathogen that causes severe invasive disease in pigs and humans. Current methods for genome engineering of S. suis rely on the insertion of antibiotic resistance markers, which is time-consuming and labor-intensive and does not allow the precise introduction of small genomic mutations. Here we developed a system for CRISPR-based genome editing in S. suis, utilizing linear DNA fragments for homologous recombination (HR) and a plasmid-based negative selection system for bacteria not edited by HR. To enable the use of this system in other bacteria, we engineered a broad-host-range replicon in the CRISPR plasmid. We demonstrated the utility of this system to rapidly introduce multiple gene deletions in successive rounds of genome editing and to make precise nucleotide changes in essential genes. Furthermore, we characterized a mechanism by which S. suis can escape killing by a targeted Cas9-sgRNA complex in the absence of HR. A characteristic of this new mechanism is the presence of very slow-growing colonies in a persister-like state that may allow for DNA repair or the introduction of mutations, alleviating Cas9 pressure. This does not impact the utility of CRISPR-based genome editing because the escape colonies are easily distinguished from genetically edited clones due to their small colony size. Our CRISPR-based editing system is a valuable addition to the genetic toolbox for engineering of S. suis, as it accelerates the process of mutant construction and simplifies the removal of antibiotic markers between successive rounds of genome editing.
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Affiliation(s)
- Alex Gussak
- Host-Microbe Interactomics, Animal
Sciences, Wageningen University, 6708 WD Wageningen, The Netherlands
| | | | | | - Peter van Baarlen
- Host-Microbe Interactomics, Animal
Sciences, Wageningen University, 6708 WD Wageningen, The Netherlands
| | - Jerry Mark Wells
- Host-Microbe Interactomics, Animal
Sciences, Wageningen University, 6708 WD Wageningen, The Netherlands
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Yang J, Jia F, Qiao Y, Hai Z, Zhou X. Correlation between bacterial extracellular vesicles and antibiotics: A potentially antibacterial strategy. Microb Pathog 2023:106167. [PMID: 37224984 DOI: 10.1016/j.micpath.2023.106167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/20/2023] [Accepted: 05/22/2023] [Indexed: 05/26/2023]
Abstract
Bacterial extracellular vesicles (BEVs) are proteoliposome nanoparticles that are secreted by both Gram-negative (G-) and Gram-positive (G+) bacteria. BEVs have significant roles in various physiological processes of bacteria, including driving inflammatory responses, regulating bacterial pathogenesis, and promoting bacterial survival in diverse environments. Recently, there has been increasing interest in the use of BEVs as a potential solution to antibiotic resistance. BEVs have shown great promise as a new approach to antibiotics, as well as a drug-delivery tool in antimicrobial strategies. In this review, we provide a summary of recent scientific advances in BEVs and antibiotics, including BEV biogenesis, ability to kill bacteria, potential for delivering antibiotics, and their role in the development of vaccines or as immune adjuvants. We propose that BEVs provide a novel antimicrobial strategy that would be beneficial against the increasing threat of antibiotic resistance.
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Affiliation(s)
- Jiangliu Yang
- College of Life Science, Ningxia University, Yinchuan, 750021, China; Key Laboratory of the Ministry of Education for the Conservation and Utilization of Special Biological Resources of Western China, Yinchuan, 750021, China
| | - Fang Jia
- Inner Mongolia Key Laboratory of Molecular Biology, Inner Mongolia Medical University, Hohhot, 010058, China
| | - Yarui Qiao
- College of Life Science, Ningxia University, Yinchuan, 750021, China; Key Laboratory of the Ministry of Education for the Conservation and Utilization of Special Biological Resources of Western China, Yinchuan, 750021, China
| | - Zhenzhen Hai
- College of Life Science, Ningxia University, Yinchuan, 750021, China; Key Laboratory of the Ministry of Education for the Conservation and Utilization of Special Biological Resources of Western China, Yinchuan, 750021, China
| | - Xuezhang Zhou
- College of Life Science, Ningxia University, Yinchuan, 750021, China; Key Laboratory of the Ministry of Education for the Conservation and Utilization of Special Biological Resources of Western China, Yinchuan, 750021, China.
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Research Progress on Bacterial Membrane Vesicles and Antibiotic Resistance. Int J Mol Sci 2022; 23:ijms231911553. [PMID: 36232856 PMCID: PMC9569563 DOI: 10.3390/ijms231911553] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/15/2022] [Accepted: 09/27/2022] [Indexed: 11/17/2022] Open
Abstract
As a result of antibiotic overuse, bacterial antibiotic resistance has become a severe threat to worldwide public health. The development of more effective antimicrobial therapies and alternative antibiotic strategies is urgently required. The role played by bacterial membrane vesicles (BMVs) in antibiotic resistance has become a current focus of research. BMVs are nanoparticles derived from the membrane components of Gram-negative and Gram-positive bacteria and contain diverse components originating from the cell envelope and cytoplasm. Antibiotic stress stimulates the secretion of BMVs. BMVs promote and mediate antibiotic resistance by multiple mechanisms. BMVs have been investigated as conceptually new antibiotics and drug-delivery vehicles. In this article, we outline the research related to BMVs and antibiotic resistance as a reference for the intentional use of BMVs to combat antibiotic resistance.
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Payen S, Roy D, Boa A, Okura M, Auger JP, Segura M, Gottschalk M. Role of Maturation of Lipoproteins in the Pathogenesis of the Infection Caused by Streptococcus suis Serotype 2. Microorganisms 2021; 9:microorganisms9112386. [PMID: 34835511 PMCID: PMC8621357 DOI: 10.3390/microorganisms9112386] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/03/2021] [Accepted: 11/15/2021] [Indexed: 11/16/2022] Open
Abstract
Streptococcus suis serotype 2 is an important porcine bacterial pathogen associated with multiple pathologies in piglets. Bacterial lipoproteins (LPPs) have been described as playing important roles in the pathogenesis of the infection of other Gram-positive bacteria as adhesins, pro-inflammatory cell activators and/or virulence factors. In the current study, we aimed to evaluate the role of the prolipoprotein diacylglyceryl transferase (Lgt) and lipoprotein signal peptidase (Lsp) enzymes, which are responsible for LPP maturation, on the pathogenesis of the infection caused by two different sequence types (STs) of S. suis serotype 2 strains (virulent ST1 and highly virulent ST7). Through the use of isogenic Δlgt, Δlsp and double Δlgt/Δlsp mutants, it was shown that lack of these enzymes did not influence S. suis adhesion/invasion to porcine respiratory epithelial cells. However, in the absence of the Lsp and/or Lgt, a significant reduction in the capacity of S. suis to activate phagocytic cells and induce pro-inflammatory mediators (in vitro and in vivo) was observed. In general, results obtained with the double mutant did not differ in comparison to single mutants, indicating lack of an additive effect. Finally, our data suggest that these enzymes play a differential role in virulence, depending on the genetic background of the strain and being more important for the highly virulent ST7 strain.
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Affiliation(s)
- Servane Payen
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
| | - David Roy
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
| | - Anaïs Boa
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
| | - Masatoshi Okura
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba 305-0856, Japan;
| | - Jean-Philippe Auger
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
| | - Mariela Segura
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
| | - Marcelo Gottschalk
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
- Correspondence:
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7
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Park OJ, Jung S, Park T, Kim AR, Lee D, Jung Ji H, Seong Seo H, Yun CH, Hyun Han S. Enhanced biofilm formation of Streptococcus gordonii with lipoprotein deficiency. Mol Oral Microbiol 2020; 35:271-278. [PMID: 33063478 DOI: 10.1111/omi.12319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 09/18/2020] [Accepted: 10/10/2020] [Indexed: 02/01/2023]
Abstract
Streptococcus gordonii is a commensal Gram-positive bacterium that acts as an opportunistic pathogen that can cause apical periodontitis, endocarditis, and pneumonia. Biofilm formation of bacteria is important for the initiation and progression of such diseases. Although lipoproteins play key roles in physiological functions, the role of lipoproteins of S. gordonii in its biofilm formation has not been clearly understood. In this study, we investigated the role of lipoproteins of S. gordonii in the bacterial biofilm formation using its lipoprotein-deficient strain (Δlgt). The S. gordonii Δlgt exhibited increased biofilm formation on the human dentin slices or on the polystyrene surfaces compared to the wild-type strain, while its growth rate did not differ from that of the wild-type. In addition, the S. gordonii Δlgt strain exhibited the enhanced LuxS mRNA expression and AI-2 production, which is known to be a positive regulator of biofilm formation, compared to the wild-type. Concordantly, the augmented biofilm formation of S. gordonii Δlgt was attenuated by an AI-2 inhibitor, D-ribose. In addition, lipoproteins from purified S. gordonii inhibited the biofilm formation of S. gordonii wild-type and Δlgt. Taken together, these results suggest that lipoprotein-deficient S. gordonii form biofilms more effectively than the wild-type strain, which might be related to the AI-2 quorum-sensing system.
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Affiliation(s)
- Ok-Jin Park
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Solmin Jung
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Taehwan Park
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - A Reum Kim
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Dongwook Lee
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Hyun Jung Ji
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea
| | - Ho Seong Seo
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea.,Institute of Green Bio Science Technology, Seoul National University, Pyeongchang, Republic of Korea
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, Republic of Korea
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Bose S, Aggarwal S, Singh DV, Acharya N. Extracellular vesicles: An emerging platform in gram-positive bacteria. MICROBIAL CELL (GRAZ, AUSTRIA) 2020; 7:312-322. [PMID: 33335921 PMCID: PMC7713254 DOI: 10.15698/mic2020.12.737] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/07/2020] [Accepted: 09/23/2020] [Indexed: 12/11/2022]
Abstract
Extracellular vesicles (EV), also known as membrane vesicles, are produced as an end product of secretion by both pathogenic and non-pathogenic bacteria. Several reports suggest that archaea, gram-negative bacteria, and eukaryotic cells secrete membrane vesicles as a means for cell-free intercellular communication. EVs influence intercellular communication by transferring a myriad of biomolecules including genetic information. Also, EVs have been implicated in many phenomena such as stress response, intercellular competition, lateral gene transfer, and pathogenicity. However, the cellular process of secreting EVs in gram-positive bacteria is less studied. A notion with the thick cell-walled microbes such as gram-positive bacteria is that the EV release is impossible among them. The role of gram-positive EVs in health and diseases is being studied gradually. Being nano-sized, the EVs from gram-positive bacteria carry a diversity of cargo compounds that have a role in bacterial competition, survival, invasion, host immune evasion, and infection. In this review, we summarise the current understanding of the EVs produced by gram-positive bacteria. Also, we discuss the functional aspects of these components while comparing them with gram-negative bacteria.
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Affiliation(s)
- Swagata Bose
- Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar-751023, India
| | - Shifu Aggarwal
- Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar-751023, India
| | - Durg Vijai Singh
- Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar-751023, India
- Department of Biotechnology, School of Earth, Biological and Environmental Sciences, Central University of South Bihar, Gaya-824236, India
| | - Narottam Acharya
- Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar-751023, India
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Recognition of Lipoproteins by Toll-like Receptor 2 and DNA by the AIM2 Inflammasome Is Responsible for Production of Interleukin-1β by Virulent Suilysin-negative Streptococcus suis Serotype 2. Pathogens 2020; 9:pathogens9020147. [PMID: 32098284 PMCID: PMC7168628 DOI: 10.3390/pathogens9020147] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 12/20/2022] Open
Abstract
Streptococcus suis serotype 2 is an important porcine bacterial pathogen and zoonotic agent causing sudden death, septic shock and meningitis. These pathologies are the consequence of an exacerbated inflammatory response composed of various mediators including interleukin (IL)-1β. Elevated levels of the toxin suilysin (SLY) were demonstrated to play a key role in S. suis-induced IL-1β production. However, 95% of serotype 2 strains isolated from diseased pigs in North America, many of which are virulent, do not produce SLY. In this study, we demonstrated that SLY-negative S. suis induces elevated levels of IL-1β in systemic organs, with dendritic cells contributing to this production. SLY-negative S. suis-induced IL-1β production requires MyD88 and TLR2 following recognition of lipoproteins. However, the higher internalization rate of the SLY-negative strain results in intracellularly located DNA being recognized by the AIM2 inflammasome, which promotes IL-1β production. Finally, the role of IL-1 in host survival during the S. suis systemic infection is beneficial and conserved, regardless of SLY production, via modulation of the inflammation required to control bacterial burden. In conclusion, this study demonstrates that SLY is not required for S. suis-induced IL-1β production.
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Lavagna A, Auger JP, Dumesnil A, Roy D, Girardin SE, Gisch N, Segura M, Gottschalk M. Interleukin-1 signaling induced by Streptococcus suis serotype 2 is strain-dependent and contributes to bacterial clearance and inflammation during systemic disease in a mouse model of infection. Vet Res 2019; 50:52. [PMID: 31262357 PMCID: PMC6604435 DOI: 10.1186/s13567-019-0670-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/14/2019] [Indexed: 12/12/2022] Open
Abstract
Streptococcus suis serotype 2 is an important porcine pathogen and zoonotic agent causing sudden death, septic shock and meningitis, with exacerbated inflammation being a hallmark of the infection. A rapid, effective and balanced innate immune response against S. suis is critical to control bacterial growth without causing excessive inflammation. Even though interleukin (IL)-1 is one of the most potent and earliest pro-inflammatory mediators produced, its role in the S. suis pathogenesis has not been studied. We demonstrated that a classical virulent European sequence type (ST) 1 strain and the highly virulent ST7 strain induce important levels of IL-1 in systemic organs. Moreover, bone marrow-derived dendritic cells and macrophages contribute to its production, with the ST7 strain inducing higher levels. To better understand the underlying mechanisms involved, different cellular pathways were studied. Independently of the strain, IL-1β production required MyD88 and involved recognition via TLR2 and possibly TLR7 and TLR9. This suggests that the recognized bacterial components are similar and conserved between strains. However, very high levels of the pore-forming toxin suilysin, produced only by the ST7 strain, are required for efficient maturation of pro-IL-1β via activation of different inflammasomes resulting from pore formation and ion efflux. Using IL-1R−/− mice, we demonstrated that IL-1 signaling plays a beneficial role during S. suis systemic infection by modulating the inflammation required to control and clear bacterial burden, thus promoting host survival. Beyond a certain threshold, however, S. suis-induced inflammation cannot be counterbalanced by this signaling, making it difficult to discriminate its role.
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Affiliation(s)
- Agustina Lavagna
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Jean-Philippe Auger
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Audrey Dumesnil
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - David Roy
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Stephen E Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Mariela Segura
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Marcelo Gottschalk
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada.
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Jang AY, Ahn KB, Zhi Y, Ji HJ, Zhang J, Han SH, Guo H, Lim S, Song JY, Lim JH, Seo HS. Serotype-Independent Protection Against Invasive Pneumococcal Infections Conferred by Live Vaccine With lgt Deletion. Front Immunol 2019; 10:1212. [PMID: 31191555 PMCID: PMC6549034 DOI: 10.3389/fimmu.2019.01212] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/13/2019] [Indexed: 01/10/2023] Open
Abstract
Streptococcus pneumoniae is the most common respiratory bacterial pathogen among cases of community-acquired infection in young children, older adults, and individuals with underlying medical conditions. Although capsular polysaccharide-based pneumococcal vaccines have contributed to significant decrease in invasive pneumococcal infections, these vaccines have some limitations, including limited serotype coverage, lack of effective mucosal antibody responses, and high costs. In this study, we investigated the safety and immunogenicity of a live, whole-cell pneumococcal vaccine constructed by deleting the gene for prolipoprotein diacylglyceryl transferase (lgt) from the encapsulated pneumococcal strain TIGR4 (TIGR4Δlgt) for protection against heterologous pneumococcal strains. Pneumococcal strain TIGR4 was successfully attenuated by deletion of lgt, resulting in the loss of inflammatory activity and virulence. TIGR4Δlgt colonized the nasopharynx long enough to induce strong mucosal IgA and IgG2b-dominant systemic antibody responses that were cross-reactive to heterologous pneumococcal serotypes. Finally, intranasal immunization with TIGR4Δlgt provided serotype-independent protection against pneumococcal challenge in mice. Taken together, our results suggest that TIGR4Δlgt is an avirulent and attractive broad-spectrum pneumococcal vaccine candidate. More broadly, we assert that modulation of such "master" metabolic genes represents an emerging strategy for developing more effective vaccines against numerous infectious agents.
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Affiliation(s)
- A-Yeung Jang
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, South Korea.,Department of Internal Medicine, Korea University College of Medicine, Seoul, South Korea
| | - Ki Bum Ahn
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, South Korea
| | - Yong Zhi
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, South Korea.,Department of Radiation Science and Technology, University of Science and Technology, Daejeon, South Korea
| | - Hyun-Jung Ji
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, South Korea.,DRI and BK21 Plus Program, Department of Oral Microbiology and Immunology, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Jing Zhang
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, South Korea
| | - Seung Hyun Han
- DRI and BK21 Plus Program, Department of Oral Microbiology and Immunology, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Huichen Guo
- State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Sangyong Lim
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, South Korea.,Department of Radiation Science and Technology, University of Science and Technology, Daejeon, South Korea
| | - Joon Yong Song
- Department of Internal Medicine, Korea University College of Medicine, Seoul, South Korea
| | - Jae Hyang Lim
- Department of Microbiology, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Ho Seong Seo
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, South Korea.,Department of Radiation Science and Technology, University of Science and Technology, Daejeon, South Korea
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12
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Andreoni F, Toyofuku M, Menzi C, Kalawong R, Mairpady Shambat S, François P, Zinkernagel AS, Eberl L. Antibiotics Stimulate Formation of Vesicles in Staphylococcus aureus in both Phage-Dependent and -Independent Fashions and via Different Routes. Antimicrob Agents Chemother 2019; 63:e01439-18. [PMID: 30509943 PMCID: PMC6355553 DOI: 10.1128/aac.01439-18] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/18/2018] [Indexed: 12/29/2022] Open
Abstract
Bacterial membrane vesicle research has so far focused mainly on Gram-negative bacteria. Only recently have Gram-positive bacteria been demonstrated to produce and release extracellular membrane vesicles (MVs) that contribute to bacterial virulence. Although treatment of bacteria with antibiotics is a well-established trigger of bacterial MV formation, the underlying mechanisms are poorly understood. In this study, we show that antibiotics can induce MVs through different routes in the important human pathogen Staphylococcus aureus DNA-damaging agents and antibiotics inducing the SOS response triggered vesicle formation in lysogenic strains of S. aureus but not in their phage-devoid counterparts. The β-lactam antibiotics flucloxacillin and ceftaroline increased vesicle formation in a prophage-independent manner by weakening the peptidoglycan layer. We present evidence that the amount of DNA associated with MVs formed by phage lysis is greater than that for MVs formed by β-lactam antibiotic-induced blebbing. The purified MVs derived from S. aureus protected the bacteria from challenge with daptomycin, a membrane-targeting antibiotic, both in vitro and ex vivo in whole blood. In addition, the MVs protected S. aureus from killing in whole blood, indicating that antibiotic-induced MVs function as a decoy and thereby contribute to the survival of the bacterium.
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Affiliation(s)
- Federica Andreoni
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Masanori Toyofuku
- Department of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Carmen Menzi
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Ratchara Kalawong
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Srikanth Mairpady Shambat
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Patrice François
- Laboratoire de Recherche Génomique, Service des Maladies Infectieuses, Centre Médical Universitaire, Geneva, Switzerland
| | - Annelies S Zinkernagel
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Leo Eberl
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
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13
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Obaidullah AJ, Ahmed MH, Kitten T, Kellogg GE. Inhibiting Pneumococcal Surface Antigen A (PsaA) with Small Molecules Discovered through Virtual Screening: Steps toward Validating a Potential Target for Streptococcus pneumoniae. Chem Biodivers 2018; 15:e1800234. [PMID: 30221472 DOI: 10.1002/cbdv.201800234] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 09/14/2018] [Indexed: 11/09/2022]
Abstract
The pneumococcal surface antigen A (PsaA) metal transporter protein provides manganese to bacterial cells. The X-ray crystal structures of PsaA, in both closed (Mn bound) and open (metal free) conformations, were explored with virtual screening to identify potential inhibitors of manganese transport. We pursued three strategies for inhibition: i) targeting a cavity close to the bound Mn to keep the metal in place; ii) targeting the metal-free Mn site to prevent metal uptake; and iii) targeting a potentially druggable allosteric site involving loops that translate between the conformations. Tiered assays were used to test the resulting 170 acquired hits: i) assay 1 tested the compounds' growth inhibition of the TIGR4 S. pneumoniae strain (ΔPsaA mutant control), yielding 80 compounds (MIC≤250 μm); ii) assay 2 tested if the addition of 20 μm Mn to inhibited cell cultures restored growth, yielding 21 compounds; and iii) assay 3 confirmed that the restored bacterial growth was Mn concentration dependent, as was the restoration of ΔPsaA growth, yielding 12 compounds with MICs of 125 μm or greater. It may be possible for a small molecule to inhibit PsaA, but we have not yet identified a compound with exemplary properties.
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Affiliation(s)
- Ahmad J Obaidullah
- Department of Medicinal Chemistry & Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA.,Current address: Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Mostafa H Ahmed
- Department of Medicinal Chemistry & Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA
| | - Todd Kitten
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia, 23298-0566, USA
| | - Glen E Kellogg
- Department of Medicinal Chemistry & Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia, 23298-0540, USA
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14
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Toyofuku M, Nomura N, Eberl L. Types and origins of bacterial membrane vesicles. Nat Rev Microbiol 2018; 17:13-24. [DOI: 10.1038/s41579-018-0112-2] [Citation(s) in RCA: 396] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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15
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Gisch N, Auger JP, Thomsen S, Roy D, Xu J, Schwudke D, Gottschalk M. Structural analysis and immunostimulatory potency of lipoteichoic acids isolated from three Streptococcus suis serotype 2 strains. J Biol Chem 2018; 293:12011-12025. [PMID: 29884769 PMCID: PMC6078451 DOI: 10.1074/jbc.ra118.002174] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 06/06/2018] [Indexed: 12/31/2022] Open
Abstract
Streptococcus suis serotype 2 is an important porcine and human pathogen. Lipoteichoic acid (LTA) from S. suis has been suggested to contribute to its virulence, and absence of d-alanylation from the S. suis LTA is associated with increased susceptibility to cationic antimicrobial peptides. Here, using high-resolution NMR spectroscopy and MS analyses, we characterized the LTA structures from three S. suis serotype 2 strains differing in virulence, sequence type (ST), and geographical origin. Our analyses revealed that these strains possess-in addition to the typical type I LTA present in other streptococci-a second, mixed-type series of LTA molecules of high complexity. We observed a ST-specific difference in the incorporation of glycosyl residues into these mixed-type LTAs. We found that strains P1/7 (ST1, high virulence) and SC84 (ST7, very high virulence) can attach a 1,2-linked α-d-Glcp residue as branching substituent to an α-d-Glcp that is 1,3-linked to glycerol phosphate moieties and that is not present in strain 89-1591 (ST25, intermediate virulence). In contrast, the latter strain could glycosylate its LTA at the glycerol O-2 position, which was not observed in the other two strains. Using LTA preparations from WT strains and from mutants with an inactivated prolipoprotein diacylglyceryl transferase, resulting in deficient lipoprotein acylation, we show that S. suis LTAs alone do not induce Toll-like receptor 2-dependent pro-inflammatory mediator production from dendritic cells. In summary, our study reveals an unexpected complexity of LTAs present in three S. suis serotype 2 strains differing in genetic background and virulence.
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Affiliation(s)
- Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, 23845 Borstel, Germany.
| | - Jean-Philippe Auger
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec J2S 2M2, Canada
| | - Simone Thomsen
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, 23845 Borstel, Germany
| | - David Roy
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec J2S 2M2, Canada
| | - Jianguo Xu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Dominik Schwudke
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, 23845 Borstel, Germany
| | - Marcelo Gottschalk
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec J2S 2M2, Canada
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16
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Vreman S, Auray G, Savelkoul HFJ, Rebel A, Summerfield A, Stockhofe-Zurwieden N. Neonatal porcine blood derived dendritic cell subsets show activation after TLR2 or TLR9 stimulation. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 84:361-370. [PMID: 29555549 DOI: 10.1016/j.dci.2018.03.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/07/2018] [Accepted: 03/15/2018] [Indexed: 06/08/2023]
Abstract
The present study investigated the innate immune response in vitro to determine porcine neonate responses with Toll-like receptor (TLR)2 ligand (Pam3Cys) or TLR9 ligand (CpG) and compared these with adults. We identified the same phenotypically defined dendritic cell (DC) subsets and DC proportions in porcine neonate and adult blood by flow cytometry, which were plasmacytoid DCs (pDCs): CD14-CD4+CD172a+CADM1-) and conventional DCs (cDCs), being further divided into a cDC1 (CD14-CD4-CD172alowCADM1+) and a cDC2 (CD14-CD4-CD172a+CADM1+) subset. With neonatal cells, the TLR2 ligand induced a stronger TNF expression in monocytes and pDCs, and a stronger CD80/86 upregulation in cDC1, when compared to adult cells. Furthermore, in neonatal mononuclear cells TLR9 ligand was more potent at inducing IL12p40 mRNA expression. These results indicate clear responses of porcine neonatal antigen presenting cells after TLR2 and TLR9 stimulation, suggesting that corresponding ligands could be promising candidates for neonatal adjuvant application.
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Affiliation(s)
- Sandra Vreman
- Wageningen Bioveterinary Research, Wageningen University & Research, P.O. Box 29703, 2502 LS, The Hague, The Netherlands.
| | - Gael Auray
- Institute of Virology and Immunology, Sensemattstrasse 293, 3147, Mittelhausern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, Switzerland
| | - Huub F J Savelkoul
- Cell Biology & Immunology Group, Wageningen University & Research P.O. Box 338, 6700 HA, Wageningen, The Netherlands
| | - Annemarie Rebel
- Wageningen Bioveterinary Research, Wageningen University & Research, P.O. Box 29703, 2502 LS, The Hague, The Netherlands
| | - Artur Summerfield
- Institute of Virology and Immunology, Sensemattstrasse 293, 3147, Mittelhausern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, Switzerland
| | - Norbert Stockhofe-Zurwieden
- Wageningen Bioveterinary Research, Wageningen University & Research, P.O. Box 29703, 2502 LS, The Hague, The Netherlands
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17
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Kim AR, Ahn KB, Kim HY, Seo HS, Kum KY, Yun C, Han SH. Streptococcus gordonii lipoproteins induce IL-8 in human periodontal ligament cells. Mol Immunol 2017; 91:218-224. [DOI: 10.1016/j.molimm.2017.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/06/2017] [Accepted: 09/18/2017] [Indexed: 12/21/2022]
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18
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Bastos PAD, da Costa JP, Vitorino R. A glimpse into the modulation of post-translational modifications of human-colonizing bacteria. J Proteomics 2016; 152:254-275. [PMID: 27888141 DOI: 10.1016/j.jprot.2016.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/22/2016] [Accepted: 11/07/2016] [Indexed: 12/19/2022]
Abstract
Protein post-translational modifications (PTMs) are a key bacterial feature that holds the capability to modulate protein function and responses to environmental cues. Until recently, their role in the regulation of prokaryotic systems has been largely neglected. However, the latest developments in mass spectrometry-based proteomics have allowed an unparalleled identification and quantification of proteins and peptides that undergo PTMs in bacteria, including in species which directly or indirectly affect human health. Herein, we address this issue by carrying out the largest and most comprehensive global pooling and comparison of PTM peptides and proteins from bacterial species performed to date. Data was collected from 91 studies relating to PTM bacterial peptides or proteins identified by mass spectrometry-based methods. The present analysis revealed that there was a considerable overlap between PTMs across species, especially between acetylation and other PTMs, particularly succinylation. Phylogenetically closer species may present more overlapping phosphoproteomes, but environmental triggers also contribute to this proximity. PTMs among bacteria were found to be extremely versatile and diverse, meaning that the same protein may undergo a wide variety of different modifications across several species, but it could also suffer different modifications within the same species.
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Affiliation(s)
- Paulo André Dias Bastos
- Department of Medical Sciences, Institute for Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal; Department of Chemistry, University of Aveiro, Portugal
| | | | - Rui Vitorino
- Department of Medical Sciences, Institute for Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal; Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal.
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19
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Wichgers Schreur PJ, van Keulen L, Kant J, Oreshkova N, Moormann RJM, Kortekaas J. Co-housing of Rift Valley Fever Virus Infected Lambs with Immunocompetent or Immunosuppressed Lambs Does Not Result in Virus Transmission. Front Microbiol 2016; 7:287. [PMID: 27014211 PMCID: PMC4779905 DOI: 10.3389/fmicb.2016.00287] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/23/2016] [Indexed: 12/13/2022] Open
Abstract
Rift Valley fever virus (RVFV) is transmitted among susceptible animals by mosquito vectors. Although the virus can be isolated from nasal and oral swabs of infected animals and is known to be highly infectious when administered experimentally via oral or respiratory route, horizontal transmission of the virus is only sporadically reported in literature. We considered that immunosuppression resulting from stressful conditions in the field may increase the susceptibility to horizontally transmitted RVFV. Additionally, we reasoned that horizontal transmission may induce immune responses that could affect the susceptibility of contact-exposed animals to subsequent infection via mosquito vectors. To address these two hypotheses, viremic lambs were brought into contact with sentinel lambs. One group of sentinel lambs was treated with the immunosuppressive synthetic glucocorticosteroid dexamethasone and monitored for signs of disease and presence of virus in the blood and target organs. Another group of contact-exposed sentinel lambs remained untreated for three weeks and was subsequently challenged with RVFV. We found that none of the dexamethasone-treated contact-exposed lambs developed detectable viremia, antibody responses or significant increases in cytokine mRNA levels. Susceptibility of immunocompetent lambs to RVFV infection was not influenced by previous contact-exposure. Our results are discussed in light of previous findings.
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Affiliation(s)
- Paul J. Wichgers Schreur
- Department of Virology, Central Veterinary Institute, Part of Wageningen University and Research CentreLelystad, Netherlands
| | - Lucien van Keulen
- Department of Virology, Central Veterinary Institute, Part of Wageningen University and Research CentreLelystad, Netherlands
| | - Jet Kant
- Department of Virology, Central Veterinary Institute, Part of Wageningen University and Research CentreLelystad, Netherlands
| | - Nadia Oreshkova
- Department of Virology, Central Veterinary Institute, Part of Wageningen University and Research CentreLelystad, Netherlands
| | - Rob J. M. Moormann
- Department of Virology, Central Veterinary Institute, Part of Wageningen University and Research CentreLelystad, Netherlands
- Virology Division, Faculty of Veterinary Medicine, Department of Infectious Diseases and Immunology, Utrecht UniversityUtrecht, Netherlands
| | - Jeroen Kortekaas
- Department of Virology, Central Veterinary Institute, Part of Wageningen University and Research CentreLelystad, Netherlands
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20
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Oreshkova N, Wichgers Schreur PJ, Spel L, Vloet RPM, Moormann RJM, Boes M, Kortekaas J. Nonspreading Rift Valley Fever Virus Infection of Human Dendritic Cells Results in Downregulation of CD83 and Full Maturation of Bystander Cells. PLoS One 2015; 10:e0142670. [PMID: 26575844 PMCID: PMC4648518 DOI: 10.1371/journal.pone.0142670] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/26/2015] [Indexed: 01/08/2023] Open
Abstract
Vaccines based on nonspreading Rift Valley fever virus (NSR) induce strong humoral and robust cellular immune responses with pronounced Th1 polarisation. The present work was aimed to gain insight into the molecular basis of NSR-mediated immunity. Recent studies have demonstrated that wild-type Rift Valley fever virus efficiently targets and replicates in dendritic cells (DCs). We found that NSR infection of cultured human DCs results in maturation of DCs, characterized by surface upregulation of CD40, CD80, CD86, MHC-I and MHC-II and secretion of the proinflammatory cytokines IFN-β, IL-6 and TNF. Interestingly, expression of the most prominent marker of DC maturation, CD83, was consistently downregulated at 24 hours post infection. Remarkably, NSR infection also completely abrogated CD83 upregulation by LPS. Downregulation of CD83 was not associated with reduced mRNA levels or impaired CD83 mRNA transport from the nucleus and could not be prevented by inhibition of the proteasome or endocytic degradation pathways, suggesting that suppression occurs at the translational level. In contrast to infected cells, bystander DCs displayed full maturation as evidenced by upregulation of CD83. Our results indicate that bystander DCs play an important role in NSR-mediated immunity.
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Affiliation(s)
- Nadia Oreshkova
- Department of Virology, Central Veterinary Institute, part of Wageningen University and Research Centre, Lelystad, The Netherlands
- Department of Infectious Diseases and Immunology, Virology Division, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Paul J. Wichgers Schreur
- Department of Virology, Central Veterinary Institute, part of Wageningen University and Research Centre, Lelystad, The Netherlands
| | - Lotte Spel
- Department of Pediatric Immunology and Laboratory of Translational Immunology, University Medical Centre Utrecht/Wilhelmina Children’s Hospital, Utrecht, The Netherlands
| | - Rianka P. M. Vloet
- Department of Virology, Central Veterinary Institute, part of Wageningen University and Research Centre, Lelystad, The Netherlands
| | - Rob J. M. Moormann
- Department of Virology, Central Veterinary Institute, part of Wageningen University and Research Centre, Lelystad, The Netherlands
- Department of Infectious Diseases and Immunology, Virology Division, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Marianne Boes
- Department of Pediatric Immunology and Laboratory of Translational Immunology, University Medical Centre Utrecht/Wilhelmina Children’s Hospital, Utrecht, The Netherlands
| | - Jeroen Kortekaas
- Department of Virology, Central Veterinary Institute, part of Wageningen University and Research Centre, Lelystad, The Netherlands
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21
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Ocvirk S, Sava IG, Lengfelder I, Lagkouvardos I, Steck N, Roh JH, Tchaptchet S, Bao Y, Hansen JJ, Huebner J, Carroll IM, Murray BE, Sartor RB, Haller D. Surface-Associated Lipoproteins Link Enterococcus faecalis Virulence to Colitogenic Activity in IL-10-Deficient Mice Independent of Their Expression Levels. PLoS Pathog 2015; 11:e1004911. [PMID: 26067254 PMCID: PMC4466351 DOI: 10.1371/journal.ppat.1004911] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 04/24/2015] [Indexed: 12/22/2022] Open
Abstract
The commensal Enterococcus faecalis is among the most common causes of nosocomial infections. Recent findings regarding increased abundance of enterococci in the intestinal microbiota of patients with inflammatory bowel diseases and induction of colitis in IL-10-deficient (IL-10-/-) mice put a new perspective on the contribution of E. faecalis to chronic intestinal inflammation. Based on the expression of virulence-related genes in the inflammatory milieu of IL-10-/- mice using RNA-sequencing analysis, we characterized the colitogenic role of two bacterial structures that substantially impact on E. faecalis virulence by different mechanisms: the enterococcal polysaccharide antigen and cell surface-associated lipoproteins. Germ-free wild type and IL-10-/- mice were monoassociated with E. faecalis wild type OG1RF or the respective isogenic mutants for 16 weeks. Intestinal tissue and mesenteric lymph nodes (MLN) were collected to characterize tissue pathology, loss of intestinal barrier function, bacterial adhesion to intestinal epithelium and immune cell activation. Bone marrow-derived dendritic cells (BMDC) were stimulated with bacterial lysates and E. faecalis virulence was additionally investigated in three invertebrate models. Colitogenic activity of wild type E. faecalis (OG1RF score: 7.2±1.2) in monoassociated IL-10-/- mice was partially impaired in E. faecalis lacking enterococcal polysaccharide antigen (ΔepaB score: 4.7±2.3; p<0.05) and was almost completely abrogated in E. faecalis deficient for lipoproteins (Δlgt score: 2.3±2.3; p<0.0001). Consistently both E. faecalis mutants showed significantly impaired virulence in Galleria mellonella and Caenorhabditis elegans. Loss of E-cadherin in the epithelium was shown for all bacterial strains in inflamed IL-10-/- but not wild type mice. Inactivation of epaB in E. faecalis reduced microcolony and biofilm formation in vitro, altered bacterial adhesion to intestinal epithelium of germ-free Manduca sexta larvae and impaired penetration into the colonic mucus layer of IL-10-/- mice. Lipoprotein-deficient E. faecalis exhibited an impaired TLR2-mediated activation of BMDCs in vitro despite their ability to fully reactivate MLN cells as well as MLN-derived colitogenic T cells ex vivo. E. faecalis virulence factors accounting for bacterial adhesion to mucosal surfaces as well as intestinal barrier disruption partially contribute to colitogenic activity of E. faecalis. Beyond their well-known role in infections, cell surface-associated lipoproteins are essential structures for colitogenic activity of E. faecalis by mediating innate immune cell activation. Enterococcus faecalis is a commensal of the human intestinal core microbiota harboring several putative virulence factors, which highlight its role as opportunistic pathogen. This dualistic character is supported by recent evidence linking Enterococcus spp. to the pathogenesis of inflammatory bowel diseases (IBD). Although several studies suggest a crucial role for opportunistic pathogens in IBD pathogenesis targeting genetically susceptible individuals, the dynamic relationship between disease-relevant host compartments and specific bacterial structures able to trigger intestinal inflammation remain unclear. Here, we report that cell surface-associated lipoproteins and the enterococcal polysaccharide antigen, which are relevant for E. faecalis virulence in invertebrate infection models, but whose expression is minimally affected by the intestinal inflammatory milieu, exhibit colitogenic activity in a mouse model susceptible for chronic colitis. Bacterial lipoproteins trigger innate immune cell activation and are a critical prerequisite for E. faecalis-induced colitis. The enterococcal polysaccharide antigen mediates bacterial mucus penetration and adhesion to mucosal surfaces, promotes the formation of biofilm and contributes to E. faecalis colitogenic activity. Using E. faecalis as a model organism, we demonstrate that colitogenic activity of opportunistic pathogens can be assigned to specific bacterial structures, a finding that may help to identify the most essential steps in IBD-related microbe-host interactions.
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Affiliation(s)
- Soeren Ocvirk
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Irina G. Sava
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Isabella Lengfelder
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Ilias Lagkouvardos
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Natalie Steck
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
| | - Jung H. Roh
- Division of Infectious Diseases, Department of Internal Medicine, The University of Texas Medical School, Houston, Texas, United States of America
| | - Sandrine Tchaptchet
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Yinyin Bao
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Jonathan J. Hansen
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Johannes Huebner
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Ian M. Carroll
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Barbara E. Murray
- Division of Infectious Diseases, Department of Internal Medicine, The University of Texas Medical School, Houston, Texas, United States of America
| | - R. Balfour Sartor
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Dirk Haller
- Technische Universität München, Chair of Nutrition and Immunology, ZIEL–Research Center for Nutrition and Food Sciences, Freising-Weihenstephan, Germany
- * E-mail:
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22
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Biagini M, Garibaldi M, Aprea S, Pezzicoli A, Doro F, Becherelli M, Taddei AR, Tani C, Tavarini S, Mora M, Teti G, D'Oro U, Nuti S, Soriani M, Margarit I, Rappuoli R, Grandi G, Norais N. The Human Pathogen Streptococcus pyogenes Releases Lipoproteins as Lipoprotein-rich Membrane Vesicles. Mol Cell Proteomics 2015; 14:2138-49. [PMID: 26018414 DOI: 10.1074/mcp.m114.045880] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Indexed: 01/24/2023] Open
Abstract
Bacterial lipoproteins are attractive vaccine candidates because they represent a major class of cell surface-exposed proteins in many bacteria and are considered as potential pathogen-associated molecular patterns sensed by Toll-like receptors with built-in adjuvanticity. Although Gram-negative lipoproteins have been extensively characterized, little is known about Gram-positive lipoproteins. We isolated from Streptococcus pyogenes a large amount of lipoproteins organized in vesicles. These vesicles were obtained by weakening the bacterial cell wall with a sublethal concentration of penicillin. Lipid and proteomic analysis of the vesicles revealed that they were enriched in phosphatidylglycerol and almost exclusively composed of lipoproteins. In association with lipoproteins, a few hypothetical proteins, penicillin-binding proteins, and several members of the ExPortal, a membrane microdomain responsible for the maturation of secreted proteins, were identified. The typical lipidic moiety was apparently not necessary for lipoprotein insertion in the vesicle bilayer because they were also recovered from the isogenic diacylglyceryl transferase deletion mutant. The vesicles were not able to activate specific Toll-like receptor 2, indicating that lipoproteins organized in these vesicular structures do not act as pathogen-associated molecular patterns. In light of these findings, we propose to name these new structures Lipoprotein-rich Membrane Vesicles.
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Affiliation(s)
- Massimiliano Biagini
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Manuela Garibaldi
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Susanna Aprea
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Alfredo Pezzicoli
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Francesco Doro
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Marco Becherelli
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Anna Rita Taddei
- §Centro Interdipartimentale di Microscopia Elettronica, Università della Tuscia, Viterbo, Italy
| | - Chiara Tani
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Simona Tavarini
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Marirosa Mora
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Giuseppe Teti
- ¶Dipartimento di Scienze Pediatriche, Ginecologiche, Microbiologiche e Biomediche, Università degli Studi di Messina, Messina, Italy
| | - Ugo D'Oro
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Sandra Nuti
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Marco Soriani
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Immaculada Margarit
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Rino Rappuoli
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Guido Grandi
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay
| | - Nathalie Norais
- From the ‡Novartis Vaccines and Diagnostics (a GSK company), Via Fiorentiina 1, 53100 Siena, Itlay;
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Hulst M, Gross G, Liu Y, Hoekman A, Niewold T, van der Meulen J, Smits M. Oral administration of Lactobacillus plantarum 299v modulates gene expression in the ileum of pigs: prediction of crosstalk between intestinal immune cells and sub-mucosal adipocytes. GENES AND NUTRITION 2015; 10:10. [PMID: 25861755 PMCID: PMC4393378 DOI: 10.1007/s12263-015-0461-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 03/28/2015] [Indexed: 12/21/2022]
Abstract
To study host-probiotic interactions in parts of the intestine only accessible in humans by surgery (jejunum, ileum and colon), pigs were used as model for humans. Groups of eight 6-week-old pigs were repeatedly orally administered with 5 × 10(12) CFU Lactobacillus plantarum 299v (L. plantarum 299v) or PBS, starting with a single dose followed by three consecutive daily dosings 10 days later. Gene expression was assessed with pooled RNA samples isolated from jejunum, ileum and colon scrapings of the eight pigs per group using Affymetrix porcine microarrays. Comparison of gene expression profiles recorded from L. plantarum 299v-treated pigs with PBS-treated pigs indicated that L. plantarum 299v affected metabolic and immunological processes, particularly in the ileum. A higher expression level of several B cell-specific transcription factors/regulators was observed, suggesting that an influx of B cells from the periphery to the ileum and/or the proliferation of progenitor B cells to IgA-committed plasma cells in the Peyer's patches of the ileum was stimulated. Genes coding for enzymes that metabolize leukotriene B4, 1,25-dihydroxyvitamin D3 and steroids were regulated in the ileum. Bioinformatics analysis predicted that these metabolites may play a role in the crosstalk between intestinal immune cells and sub-mucosal adipocytes. Together with regulation of genes that repress NFKB- and PPARG-mediated transcription, this crosstalk may contribute to tempering of inflammatory reactions. Furthermore, the enzyme adenosine deaminase, responsible for the breakdown of the anti-inflammatory mediator adenosine, was strongly down-regulated in response to L. plantarum 299v. This suggested that L. plantarum 299v-regulated production of adenosine by immune cells like regulatory T cells may also be a mechanism that tempers inflammation in the ileum, and perhaps also in other parts of the pig's body.
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Affiliation(s)
- Marcel Hulst
- />Animal Breeding and Genomics Centre, Animal Sciences Group of Wageningen UR, P.O. Box 338, 6700 AH Wageningen, The Netherlands
| | - Gabriele Gross
- />Animal Breeding and Genomics Centre, Animal Sciences Group of Wageningen UR, P.O. Box 338, 6700 AH Wageningen, The Netherlands
- />Mead Johnson Nutrition, Nijmegen, The Netherlands
| | - Yaping Liu
- />Animal Breeding and Genomics Centre, Animal Sciences Group of Wageningen UR, P.O. Box 338, 6700 AH Wageningen, The Netherlands
- />USC Epigenome Center, University of Southern California, Los Angeles, CA USA
| | - Arjan Hoekman
- />Animal Breeding and Genomics Centre, Animal Sciences Group of Wageningen UR, P.O. Box 338, 6700 AH Wageningen, The Netherlands
| | - Theo Niewold
- />Nutrition and Health, Katholieke Universiteit Leuven, Kasteelpark Arenberg 30, 3001 Heverlee, Belgium
| | - Jan van der Meulen
- />Animal Breeding and Genomics Centre, Animal Sciences Group of Wageningen UR, P.O. Box 338, 6700 AH Wageningen, The Netherlands
- />Central Veterinary Institute, Animal Sciences Group of Wageningen UR, P.O. Box 65, 8200 AB Lelystad, The Netherlands
| | - Mari Smits
- />Animal Breeding and Genomics Centre, Animal Sciences Group of Wageningen UR, P.O. Box 338, 6700 AH Wageningen, The Netherlands
- />Central Veterinary Institute, Animal Sciences Group of Wageningen UR, P.O. Box 65, 8200 AB Lelystad, The Netherlands
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24
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Buddelmeijer N. The molecular mechanism of bacterial lipoprotein modification—How, when and why? FEMS Microbiol Rev 2015; 39:246-61. [DOI: 10.1093/femsre/fuu006] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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de Greeff A, Buys H, Wells JM, Smith HE. A naturally occurring nucleotide polymorphism in the orf2/folc promoter is associated with Streptococcus suis virulence. BMC Microbiol 2014; 14:264. [PMID: 25384512 PMCID: PMC4232619 DOI: 10.1186/s12866-014-0264-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 10/09/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Streptococcus suis is a major problem in the swine industry causing meningitis, arthritis and pericarditis in piglets. Pathogenesis of S. suis is poorly understood. We previously showed that introduction of a 3 kb genomic fragment from virulent serotype 2 strain 10 into a weakly virulent serotype 2 strain S735, generated a hypervirulent isolate. The 3 kb genomic fragment contained two complete open reading frames (ORF) in an operon-structure of which one ORF showed similarity to folylpolyglutamate synthetase, whereas the function of the second ORF could not be predicted based on database searches for protein similarity. RESULTS In this study we demonstrate that introduction of orf2 from strain 10 into strain S735 is sufficient to dramatically increase the virulence of S735 in pigs. This increase in virulence could not be associated with changes in pro-inflammatory responses of porcine blood mononucleated cells in response to S. suis in vitro. Sequence analysis of the orf2-folC-operon of S. suis isolates 10 and S735 revealed an SNP in the -35 region of the putative promoter sequence of the operon, as well as several SNPs resulting in amino acid substitutions in the ORF2 protein. Transcript levels of orf2 and folC were significantly higher in the virulent strain 10 than in the weakly virulent strain S735 and in vitro mutagenesis of the orf2 promoter confirmed that this was due to a SNP in the predicted -35 region upstream of the orf2 promoter. In this study, we demonstrated that the stronger promoter was present in all virulent and highly virulent S. suis isolates included in our study. This highlights a correlation between high orf2 expression and virulence. Conversely, the weaker promoter was present in isolates known to be weakly pathogenic or non-pathogenic. CONCLUSION In summary, we demonstrate the importance of orf2 in the virulence of S. suis.
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Affiliation(s)
- Astrid de Greeff
- Central Veterinary Institute of Wageningen UR, Edelhertweg 15, 8219, , PH, Lelystad, The Netherlands.
| | - Herma Buys
- Central Veterinary Institute of Wageningen UR, Edelhertweg 15, 8219, , PH, Lelystad, The Netherlands.
| | - Jerry M Wells
- Wageningen UR, Host Microbe Interactions, De Elst 1, 6708, , WD, Wageningen, The Netherlands.
| | - Hilde E Smith
- Central Veterinary Institute of Wageningen UR, Edelhertweg 15, 8219, , PH, Lelystad, The Netherlands.
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Laouami S, Clair G, Armengaud J, Duport C. Proteomic evidences for rex regulation of metabolism in toxin-producing Bacillus cereus ATCC 14579. PLoS One 2014; 9:e107354. [PMID: 25216269 PMCID: PMC4162614 DOI: 10.1371/journal.pone.0107354] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 08/14/2014] [Indexed: 01/07/2023] Open
Abstract
The facultative anaerobe, Bacillus cereus, causes diarrheal diseases in humans. Its ability to deal with oxygen availability is recognized to be critical for pathogenesis. The B. cereus genome comprises a gene encoding a protein with high similarities to the redox regulator, Rex, which is a central regulator of anaerobic metabolism in Bacillus subtilis and other Gram-positive bacteria. Here, we showed that B. cereus rex is monocistronic and down-regulated in the absence of oxygen. The protein encoded by rex is an authentic Rex transcriptional factor since its DNA binding activity depends on the NADH/NAD+ ratio. Rex deletion compromised the ability of B. cereus to cope with external oxidative stress under anaerobiosis while increasing B. cereus resistance against such stress under aerobiosis. The deletion of rex affects anaerobic fermentative and aerobic respiratory metabolism of B. cereus by decreasing and increasing, respectively, the carbon flux through the NADH-recycling lactate pathway. We compared both the cellular proteome and exoproteome of the wild-type and Δrex cells using a high throughput shotgun label-free quantitation approach and identified proteins that are under control of Rex-mediated regulation. Proteomics data have been deposited to the ProteomeXchange with identifier PXD000886. The data suggest that Rex regulates both the cross-talk between metabolic pathways that produce NADH and NADPH and toxinogenesis, especially in oxic conditions.
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Affiliation(s)
- Sabrina Laouami
- Avignon Université/INRA, SQPOV UMR408, Avignon, France
- INRA, SQPOV UMR408, Avignon, France
| | - Géremy Clair
- Avignon Université/INRA, SQPOV UMR408, Avignon, France
- INRA, SQPOV UMR408, Avignon, France
- Laboratoire de Biochimie des Systèmes Perturbés, CEA Marcoule, DSV-iBEB-SBTN-LBSP, Bagnols-sur-Cèze, France
| | - Jean Armengaud
- Laboratoire de Biochimie des Systèmes Perturbés, CEA Marcoule, DSV-iBEB-SBTN-LBSP, Bagnols-sur-Cèze, France
| | - Catherine Duport
- Avignon Université/INRA, SQPOV UMR408, Avignon, France
- INRA, SQPOV UMR408, Avignon, France
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27
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Schokker D, Zhang J, Zhang LL, Vastenhouw SA, Heilig HGHJ, Smidt H, Rebel JMJ, Smits MA. Early-life environmental variation affects intestinal microbiota and immune development in new-born piglets. PLoS One 2014; 9:e100040. [PMID: 24941112 PMCID: PMC4062469 DOI: 10.1371/journal.pone.0100040] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 05/22/2014] [Indexed: 02/07/2023] Open
Abstract
Background Early-life environmental variation affects gut microbial colonization and immune competence development; however, the timing and additional specifics of these processes are unknown. The impact of early-life environmental variations, as experienced under real life circumstances, on gut microbial colonization and immune development has not been studied extensively so far. We designed a study to investigate environmental variation, experienced early after birth, to gut microbial colonization and intestinal immune development. Methodology/Principal Findings To investigate effects of early-life environmental changes, the piglets of 16 piglet litters were divided into 3 groups per litter and experimentally treated on day 4 after birth. During the course of the experiment, the piglets were kept with their mother sow. Group 1 was not treated, group 2 was treated with an antibiotic, and group 3 was treated with an antibiotic and simultaneously exposed to several routine, but stressful management procedures, including docking, clipping and weighing. Thereafter, treatment effects were measured at day 8 after birth in 16 piglets per treatment group by community-scale analysis of gut microbiota and genome-wide intestinal transcriptome profiling. We observed that the applied antibiotic treatment affected the composition and diversity of gut microbiota and reduced the expression of a large number of immune-related processes. The effect of management procedures on top of the use of an antibiotic was limited. Conclusions/Significance We provide direct evidence that different early-life conditions, specifically focusing on antibiotic treatment and exposure to stress, affect gut microbial colonization and intestinal immune development. This reinforces the notion that the early phase of life is critical for intestinal immune development, also under regular production circumstances.
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Affiliation(s)
- Dirkjan Schokker
- Animal Breeding and Genomics Centre, Wageningen UR Livestock Research, Lelystad, The Netherlands
- * E-mail:
| | - Jing Zhang
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Ling-li Zhang
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | | | | | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | | | - Mari A. Smits
- Animal Breeding and Genomics Centre, Wageningen UR Livestock Research, Lelystad, The Netherlands
- Infection Biology, Central Veterinary Institute, Lelystad, The Netherlands
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Lachance C, Segura M, Gerber PP, Xu J, Gottschalk M. Toll-like receptor 2-independent host innate immune response against an epidemic strain of Streptococcus suis that causes a toxic shock-like syndrome in humans. PLoS One 2013; 8:e65031. [PMID: 23724118 PMCID: PMC3665724 DOI: 10.1371/journal.pone.0065031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 04/20/2013] [Indexed: 11/18/2022] Open
Abstract
Streptococcus suis is an emerging zoonotic agent causing meningitis and septicemia. Outbreaks in humans in China with atypical cases of streptococcal toxic shock-like syndrome have been described to be caused by a clonal epidemic S. suis strain characterized as sequence type (ST) 7 by multilocus sequence typing, different from the classical ST1 usually isolated in Europe. Previous in vitro studies showed that Toll-like receptor (TLR) 2 plays a major role in S. suis ST1 interactions with host cells. In the present study, the in vivo role of TLR2 in systemic infections caused by S. suis ST1 or ST7 strains using TLR2 deficient (TLR2(-/-)) mice was evaluated. TLR2-mediated recognition significantly contributes to the acute disease caused by the highly virulent S. suis ST1 strain, since the TLR2(-/-) mice remained unaffected when compared to wild type (WT) mice. The lack of mortality could not be associated with a lower bacterial burden; however, a significant decrease in the induction of pro-inflammatory mediators, as evaluated by microarray, real-time PCR and protein assays, was observed. On the other hand, TLR2(-/-) mice infected with the epidemic ST7 strain presented no significant differences regarding survival and expression of pro-inflammatory mediators when compared to the WT mice. Together, these results show a TLR2-independent host innate immune response to S. suis that depends on the strain.
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Affiliation(s)
- Claude Lachance
- Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Québec, Canada
| | - Mariela Segura
- Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Québec, Canada
| | - Pehuén Pereyra Gerber
- Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Québec, Canada
| | - Jianguo Xu
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Marcelo Gottschalk
- Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Québec, Canada
- * E-mail:
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Hulst M, Smits M, Vastenhouw S, de Wit A, Niewold T, van der Meulen J. Transcription networks responsible for early regulation of Salmonella-induced inflammation in the jejunum of pigs. JOURNAL OF INFLAMMATION-LONDON 2013; 10:18. [PMID: 23590759 PMCID: PMC3637394 DOI: 10.1186/1476-9255-10-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 04/10/2013] [Indexed: 05/16/2023]
Abstract
Background The aim of this study was to identify transcription factors/regulators that play a crucial role in steering the (innate) immune response shortly (within a few hours) after the first contact of the intestinal mucosa with an inflammatory mediator, and to test whether the processes regulated by these factors/regulators can be modulated by chemical substances of natural origin. Methods We experimentally induced inflammation by perfusion of surgically applied jejunal loops with Salmonella enterica subspecies enterica serovar Typhimurium DT104 in three pigs. Segments of mock and Salmonella treated loops were dissected after 2, 4 and 8 hours of perfusion. IL8 and IL1-beta mRNA expression levels were measured in mucosal scrapings of all segments. Furthermore, intra-animal microarray comparisons (isogenic) between Salmonella and mock treated segments after 8 hours, and inter-animal comparisons between similar Salmonella-treated loops of each pig at 2 and 4 hours, were performed. Results IL-1beta and IL8 mRNA levels, and intra-animal microarray comparisons at 8 hours between Salmonella and mock treated segments showed that the response-time and type of response to Salmonella was different in all three pigs. This plasticity allowed us to extract a comprehensive set of differentially expressed genes from inter-animal comparisons at 2 and 4 hours. Pathway analysis indicated that many of these genes play a role in induction and/or tempering the inflammatory response in the intestine. Among them a set of transcription factors/regulators known to be involved in regulation of inflammation, but also factors/regulators for which involvement was not expected. Nine out of twenty compounds of natural origin, which according to literature had the potential to modulate the activity of these factors/regulators, were able to stimulate or inhibit a Salmonella-induced mRNA response of inflammatory-reporter genes IL8 and/or nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha in cultured intestinal porcine epithelial cells. Conclusions We describe a set of transcription factors/regulators possibly involved in regulation of “very early” immune mechanism which determines the inflammatory status of the intestine later on. In addition, we show that these mechanisms may be modulated by chemical substances of natural origin.
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Affiliation(s)
- Marcel Hulst
- Livestock Research of Wageningen University and Research Centre, P,O, Box 65, Lelystad, 8200AB, The Netherlands.
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Weesendorp E, Morgan S, Stockhofe-Zurwieden N, Popma-De Graaf DJ, Graham SP, Rebel JMJ. Comparative analysis of immune responses following experimental infection of pigs with European porcine reproductive and respiratory syndrome virus strains of differing virulence. Vet Microbiol 2012; 163:1-12. [PMID: 23036445 PMCID: PMC7117209 DOI: 10.1016/j.vetmic.2012.09.013] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 08/31/2012] [Accepted: 09/05/2012] [Indexed: 12/28/2022]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is difficult to control due to a high mutation rate and the emergence of virulent strains. The objective of this study was to analyze the immunological and pathological responses after infection with the European subtype 3 strain Lena in comparison to subtype 1 strains Belgium A and Lelystad-Ter Huurne (LV). Sixteen pigs were inoculated per strain, and sixteen pigs with PBS. At days 7 and 21 post-inoculation (p.i.), four pigs per group were immunized with an Aujeszky disease vaccine (ADV) to study the immune competence after PRRSV infection. Infection with the Lena strain resulted in fever and clinical signs. This was not observed in the Belgium A or LV-infected pigs. Infection with the Lena strain resulted in high virus titers in serum, low numbers of IFN-γ secreting cells, a change in leukocyte populations and a delayed antibody response to immunization with ADV. Levels of IL-1β, IFN-α, IL-10, IL-12, TNF-α and IFN-γ mRNA of the Lena-infected pigs were increased during the first week of infection. For pigs infected with the Belgium A or LV strain, the effects of infection on these parameters were less pronounced, although for the Belgium A-infected pigs, the level of the analyzed cytokines, except for TNF-α, and leukocyte populations were comparable to the Lena-infected pigs. These results suggest that while the outcome of infection for the three strains was comparable, with mostly clearance of viremia at day 33 p.i, differences in immune responses were observed, perhaps contributing to their virulence.
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Affiliation(s)
- Eefke Weesendorp
- Department of Infection Biology, Central Veterinary Institute, Part of Wageningen UR, P.O. Box 65, 8200 AB, Lelystad, The Netherlands.
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Chimalapati S, Cohen JM, Camberlein E, MacDonald N, Durmort C, Vernet T, Hermans PWM, Mitchell T, Brown JS. Effects of deletion of the Streptococcus pneumoniae lipoprotein diacylglyceryl transferase gene lgt on ABC transporter function and on growth in vivo. PLoS One 2012; 7:e41393. [PMID: 22911788 PMCID: PMC3404074 DOI: 10.1371/journal.pone.0041393] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 06/21/2012] [Indexed: 12/14/2022] Open
Abstract
Lipoproteins are an important class of surface associated proteins that have diverse roles and frequently are involved in the virulence of bacterial pathogens. As prolipoproteins are attached to the cell membrane by a single enzyme, prolipoprotein diacylglyceryl transferase (Lgt), deletion of the corresponding gene potentially allows the characterisation of the overall importance of lipoproteins for specific bacterial functions. We have used a Δlgt mutant strain of Streptococcus pneumoniae to investigate the effects of loss of lipoprotein attachment on cation acquisition, growth in media containing specific carbon sources, and virulence in different infection models. Immunoblots of triton X-114 extracts, flow cytometry and immuno-fluorescence microscopy confirmed the Δlgt mutant had markedly reduced lipoprotein expression on the cell surface. The Δlgt mutant had reduced growth in cation depleted medium, increased sensitivity to oxidative stress, reduced zinc uptake, and reduced intracellular levels of several cations. Doubling time of the Δlgt mutant was also increased slightly when grown in medium with glucose, raffinose and maltotriose as sole carbon sources. These multiple defects in cation and sugar ABC transporter function for the Δlgt mutant were associated with only slightly delayed growth in complete medium. However the Δlgt mutant had significantly reduced growth in blood or bronchoalveolar lavage fluid and a marked impairment in virulence in mouse models of nasopharyngeal colonisation, sepsis and pneumonia. These data suggest that for S. pneumoniae loss of surface localisation of lipoproteins has widespread effects on ABC transporter functions that collectively prevent the Δlgt mutant from establishing invasive infection.
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Affiliation(s)
- Suneeta Chimalapati
- Centre for Respiratory Research, Department of Medicine, Royal Free and University College Medical School, Rayne Institute, London, United Kingdom
| | - Jonathan M. Cohen
- Centre for Respiratory Research, Department of Medicine, Royal Free and University College Medical School, Rayne Institute, London, United Kingdom
- Infectious Diseases & Microbiology Unit, UCL Institute of Child Health, London, United Kingdom
| | - Emilie Camberlein
- Centre for Respiratory Research, Department of Medicine, Royal Free and University College Medical School, Rayne Institute, London, United Kingdom
| | - Nathanael MacDonald
- Centre for Respiratory Research, Department of Medicine, Royal Free and University College Medical School, Rayne Institute, London, United Kingdom
| | - Claire Durmort
- CEA, Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
- CNRS, Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
- Université Joseph Fourier – Grenoble 1, Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
| | - Thierry Vernet
- CEA, Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
- CNRS, Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
- Université Joseph Fourier – Grenoble 1, Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
| | - Peter W. M. Hermans
- Laboratory of Pediatric Infectious Diseases, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Timothy Mitchell
- Division of Infection and Immunity, IBLS, University of Glasgow, Glasgow, United Kingdom
| | - Jeremy S. Brown
- Centre for Respiratory Research, Department of Medicine, Royal Free and University College Medical School, Rayne Institute, London, United Kingdom
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Fittipaldi N, Segura M, Grenier D, Gottschalk M. Virulence factors involved in the pathogenesis of the infection caused by the swine pathogen and zoonotic agent Streptococcus suis. Future Microbiol 2012; 7:259-79. [PMID: 22324994 DOI: 10.2217/fmb.11.149] [Citation(s) in RCA: 311] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Streptococcus suis is a major swine pathogen responsible for important economic losses to the swine industry worldwide. It is also an emerging zoonotic agent of meningitis and streptococcal toxic shock-like syndrome. Since the recent recognition of the high prevalence of S. suis human disease in southeast and east Asia, the interest of the scientific community in this pathogen has significantly increased. In the last few years, as a direct consequence of these intensified research efforts, large amounts of data on putative virulence factors have appeared in the literature. Although the presence of some proposed virulence factors does not necessarily define a S. suis strain as being virulent, several cell-associated or secreted factors are clearly important for the pathogenesis of the S. suis infection. In order to cause disease, S. suis must colonize the host, breach epithelial barriers, reach and survive in the bloodstream, invade different organs, and cause exaggerated inflammation. In this review, we discuss the potential contribution of different described S. suis virulence factors at each step of the pathogenesis of the infection. Finally, we briefly discuss other described virulence factors, virulence factor candidates and virulence markers for which a precise role at specific steps of the pathogenesis of the S. suis infection has not yet been clearly established.
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Affiliation(s)
- Nahuel Fittipaldi
- Groupe de Recherche sur les Maladies Infectieuses du Porc & Centre de Recherche en Infectiologie Porcine, Faculté de médecine vétérinaire, Université de Montréal, 3200 rue Sicotte, CP5000, St-Hyacinthe, Quebec, J2S 7C6, Canada
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Wichgers Schreur PJ, van Weeghel C, Rebel JMJ, Smits MA, van Putten JPM, Smith HE. Lysozyme resistance in Streptococcus suis is highly variable and multifactorial. PLoS One 2012; 7:e36281. [PMID: 22558419 PMCID: PMC3340348 DOI: 10.1371/journal.pone.0036281] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 04/04/2012] [Indexed: 12/19/2022] Open
Abstract
Background Streptococcus suis is an important infectious agent for pigs and occasionally for humans. The host innate immune system plays a key role in preventing and eliminating S. suis infections. One important constituent of the innate immune system is the protein lysozyme, which is present in a variety of body fluids and immune cells. Lysozyme acts as a peptidoglycan degrading enzyme causing bacterial lysis. Several pathogens have developed mechanisms to evade lysozyme-mediated killing. In the present study we compared the lysozyme sensitivity of various S. suis isolates and investigated the molecular basis of lysozyme resistance for this pathogen. Results The lysozyme minimal inhibitory concentrations of a wide panel of S. suis isolates varied between 0.3 to 10 mg/ml. By inactivating the oatA gene in a serotype 2 and a serotype 9 strain, we showed that OatA-mediated peptidoglycan modification partly contributes to lysozyme resistance. Furthermore, inactivation of the murMN operon provided evidence that additional peptidoglycan crosslinking is not involved in lysozyme resistance in S. suis. Besides a targeted approach, we also used an unbiased approach for identifying factors involved in lysozyme resistance. Based on whole genome comparisons of a lysozyme sensitive strain and selected lysozyme resistant derivatives, we detected several single nucleotide polymorphisms (SNPs) that were correlated with the lysozyme resistance trait. Two SNPs caused defects in protein expression of an autolysin and a capsule sugar transferase. Analysis of specific isogenic mutants, confirmed the involvement of autolysin activity and capsule structures in lysozyme resistance of S. suis. Conclusions This study shows that lysozyme resistance levels are highly variable among S. suis isolates and serotypes. Furthermore, the results show that lysozyme resistance in S. suis can involve different mechanisms including OatA-mediated peptidolycan modification, autolysin activity and capsule production.
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Affiliation(s)
- Paul J. Wichgers Schreur
- Central Veterinary Institute, Wageningen UR, Lelystad, The Netherlands
- Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, The Netherlands
| | | | | | - Mari A. Smits
- Central Veterinary Institute, Wageningen UR, Lelystad, The Netherlands
- Wageningen Livestock Research, Wageningen UR, Lelystad, The Netherlands
| | - Jos P. M. van Putten
- Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, The Netherlands
| | - Hilde E. Smith
- Central Veterinary Institute, Wageningen UR, Lelystad, The Netherlands
- * E-mail:
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Büttner N, Beineke A, de Buhr N, Lilienthal S, Merkel J, Waldmann KH, Valentin-Weigand P, Baums CG. Streptococcus suis serotype 9 bacterin immunogenicity and protective efficacy. Vet Immunol Immunopathol 2012; 146:191-200. [PMID: 22516423 DOI: 10.1016/j.vetimm.2012.03.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 03/01/2012] [Accepted: 03/26/2012] [Indexed: 10/28/2022]
Abstract
Streptococcus suis diseases in pigs, most importantly meningitis, are worldwide responsible for major economic losses in the pig industry. About one fourth of invasive S. suis diseases are caused by S. suis serotype 9 strains in Europe. However, little is known about serotype 9 since most studies were performed with serotype 2. The objective of this study was to determine the immunogenicity and protective efficacy of a serotype 9 bacterin in piglets. Challenge was conducted with a reference serotype 9 strain, belonging to the same clonal complex but to a different sequence type as the bacterin strain. The bacterin induced protection against mortality but not morbidity. Eleven days post infection, 3 of 7 vaccinated survivors were not fully convalescent and had not eliminated the challenge strain from inner organs completely. In accordance with the clinical findings, the majority of piglets showed fibrinous-suppurative lesions in at least one inner organ or tissue. In contrast to the placebo group such lesions were not detected in one third of bacterin-vaccinated piglets. Determination of specific serum IgG titers revealed that the bacterin elicited seroconversion against muramidase-released protein and basic membrane lipoprotein. Furthermore, vaccination was associated with induction of opsonizing antibodies against the serotype 9 challenge strain. However, titers of opsonizing antibodies were rather low in comparison to those found in our previous serotype 2 vaccination trial. Piglets developed substantially higher titers of opsonizing antibodies after challenge. Opsonizing antibodies were absorbable with the serotype 9 challenge strain but not with an unencapsulated isogenic mutant of a serotype 2 strain indicating their specificity. The results indicate that a serotype 9 bacterin is less protective than a serotype 2 bacterin, most likely due to inducing only low titers of opsonizing antibodies. This might contribute to emergence of serotype 9 strains, in particular strains of this clonal complex, in Europe.
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Affiliation(s)
- Nadine Büttner
- Institut für Mikrobiologie, Zentrum für Infektionsmedizin, Stiftung Tierärztliche Hochschule Hannover, D-30173 Hannover, Germany
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TroA of Streptococcus suis is required for manganese acquisition and full virulence. J Bacteriol 2011; 193:5073-80. [PMID: 21784944 DOI: 10.1128/jb.05305-11] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus suis causes infections in pigs and occasionally in humans, resulting in manifestations as meningitis, sepsis, arthritis, and septic shock. For survival within the host, S. suis requires numerous nutrients including trace metals. Little is known about the specific proteins involved in metal scavenging in S. suis. In this study we evaluated the role of the putative high-affinity metal binding lipoprotein TroA in metal acquisition and virulence. A mutant strain deficient in the expression of TroA (ΔtroA mutant) was constructed. Growth of the ΔtroA mutant in Todd-Hewitt broth was similar to wild-type growth; however, growth of the ΔtroA mutant in cation-deprived Todd-Hewitt broth and in porcine serum was strongly reduced compared to growth of wild-type bacteria. Supplementing the medium with extra manganese but not with magnesium, zinc, copper, nickel, or iron restored growth to wild-type levels, indicating that TroA is specifically required for growth in environments low in manganese. The ΔtroA mutant also showed increased susceptibility to H2O2, suggesting that TroA is involved in counteracting oxidative stress. Furthermore, the expression of the troA gene was subject to environmental regulation at the transcript level. In a murine S. suis infection model, the ΔtroA mutant displayed a nonvirulent phenotype. These data indicate that S. suis TroA is involved in manganese acquisition and is required for full virulence in mice.
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