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Xing Y, Clark JR, Chang JD, Zulk JJ, Chirman DM, Piedra FA, Vaughan EE, Hernandez Santos HJ, Patras KA, Maresso AW. Progress toward a vaccine for extraintestinal pathogenic E. coli (ExPEC) II: efficacy of a toxin-autotransporter dual antigen approach. Infect Immun 2024; 92:e0044023. [PMID: 38591882 DOI: 10.1128/iai.00440-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 03/18/2024] [Indexed: 04/10/2024] Open
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) is a leading cause of worldwide morbidity and mortality, the top cause of antimicrobial-resistant (AMR) infections, and the most frequent cause of life-threatening sepsis and urinary tract infections (UTI) in adults. The development of an effective and universal vaccine is complicated by this pathogen's pan-genome, its ability to mix and match virulence factors and AMR genes via horizontal gene transfer, an inability to decipher commensal from pathogens, and its intimate association and co-evolution with mammals. Using a pan virulome analysis of >20,000 sequenced E. coli strains, we identified the secreted cytolysin α-hemolysin (HlyA) as a high priority target for vaccine exploration studies. We demonstrate that a catalytically inactive pure form of HlyA, expressed in an autologous host using its own secretion system, is highly immunogenic in a murine host, protects against several forms of ExPEC infection (including lethal bacteremia), and significantly lowers bacterial burdens in multiple organ systems. Interestingly, the combination of a previously reported autotransporter (SinH) with HlyA was notably effective, inducing near complete protection against lethal challenge, including commonly used infection strains ST73 (CFT073) and ST95 (UTI89), as well as a mixture of 10 of the most highly virulent sequence types and strains from our clinical collection. Both HlyA and HlyA-SinH combinations also afforded some protection against UTI89 colonization in a murine UTI model. These findings suggest recombinant, inactive hemolysin and/or its combination with SinH warrant investigation in the development of an E. coli vaccine against invasive disease.
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Affiliation(s)
- Yikun Xing
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, USA
| | - Justin R Clark
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, USA
| | - James D Chang
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, USA
| | - Jacob J Zulk
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, USA
| | - Dylan M Chirman
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, USA
| | - Felipe-Andres Piedra
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
| | - Ellen E Vaughan
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
| | - Haroldo J Hernandez Santos
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, USA
| | - Kathryn A Patras
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
- Alkek Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, Texas, USA
| | - Anthony W Maresso
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, USA
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Wang XY, Miao T, Wang Y, Guo Z, Yang JL, Liang X. Complete genome sequence of Psychrobacter cibarius AOSW16051, a trimeric autotransporter adhesin synthesizing bacterium isolated from the Baltic Sea. Mar Genomics 2024; 74:101082. [PMID: 38485290 DOI: 10.1016/j.margen.2023.101082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/10/2023] [Accepted: 12/08/2023] [Indexed: 03/19/2024]
Abstract
Bacteria of the genus Psychrobacter are widely distributed in the global low-temperature marine environment and have been studied for their effects on the settlement and metamorphosis of marine invertebrates. Psychrobacter cibarius AOSW16051 was isolated from the surface water samples of the Baltic Sea on the edge of the Arctic Ocean. Here, we present the complete genome of strain AOSW16051, which consists of a circular chromosome composed of 3,425,040 nucleotides with 42.98% G + C content and a circular plasmid composed of 5846 nucleotides with 38.66% G + C content. The genes predicted in this strain showed its strong outer membrane system, type VI secretion system and adhesion system. Trimeric autotransporter adhesins (TAAs) has been identified in the genome of P. cibarius AOSW16051, which has a variety of biological functions in interacting with host cells. However, there are no reports on TAAs in marine bacteria and aquatic pathogenic bacteria. By analyzing the genomic data, we can gain valuable insights to enhance our understanding of the physiological characteristics of P. cibarius, as well as the biological functions of TAAs and their role in triggering metamorphosis of invertebrate larvae.
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Affiliation(s)
- Xiao-Yu Wang
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; China-Portugal Belt and Road Joint Laboratory on Space & Sea Technology Advanced Research, Shanghai, China; Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture animals, Shanghai, China
| | - Tianyin Miao
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; China-Portugal Belt and Road Joint Laboratory on Space & Sea Technology Advanced Research, Shanghai, China
| | - Yuyi Wang
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; China-Portugal Belt and Road Joint Laboratory on Space & Sea Technology Advanced Research, Shanghai, China; Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture animals, Shanghai, China
| | - Zhangwei Guo
- College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China.
| | - Jin-Long Yang
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; China-Portugal Belt and Road Joint Laboratory on Space & Sea Technology Advanced Research, Shanghai, China; Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture animals, Shanghai, China
| | - Xiao Liang
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; China-Portugal Belt and Road Joint Laboratory on Space & Sea Technology Advanced Research, Shanghai, China; Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture animals, Shanghai, China.
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3
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León Y, Honigsberg R, Rasko DA, Faherty CS. Gastrointestinal signals in supplemented media reveal a role in adherence for the Shigella flexneri sap autotransporter gene. Gut Microbes 2024; 16:2331985. [PMID: 38549437 PMCID: PMC10984119 DOI: 10.1080/19490976.2024.2331985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 03/14/2024] [Indexed: 04/02/2024] Open
Abstract
Shigella flexneri causes severe diarrheal disease worldwide. While many aspects of pathogenesis have been elucidated, significant knowledge gaps remain regarding the role of putative chromosomally-encoded virulence genes. The uncharacterized sap gene encoded on the chromosome has significant nucleotide sequence identity to the fluffy (flu) antigen 43 autotransporter gene in pathogenic Escherichia coli. Here, we constructed a Δsap mutant in S. flexneri strain 2457T and examined the effects of this mutation on bacterial cell aggregation, biofilm formation, and adherence to colonic epithelial cells. Analyses included the use of growth media supplemented with glucose and bile salts to replicate small intestinal signals encountered by S. flexneri. Deletion of the sap gene in 2457T affected epithelial cell adherence, resulted in quicker bacterial cell aggregation, but did not affect biofilm formation. This work highlights a functional role for the sap gene in S. flexneri pathogenesis and further demonstrates the importance of using relevant and appropriate gastrointestinal signals to characterize virulence genes of enteropathogenic bacteria.
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Affiliation(s)
- Yrvin León
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Raphael Honigsberg
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, USA
- École Normale Supérieure Paris-Saclay, Département d’Enseignement et de, Recherche de Biologie, Université Paris-Saclay, Gif-sur-Yvette, France
| | - David A. Rasko
- Institute for Genome Sciences, Center for Pathogen Research, Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Christina S. Faherty
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
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4
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Nock AM, Aistleitner K, Clark TR, Sturdevant D, Ricklefs S, Virtaneva K, Zhang Y, Gulzar N, Redekar N, Roy A, Hackstadt T. Identification of an autotransporter peptidase of Rickettsia rickettsii responsible for maturation of surface exposed autotransporters. PLoS Pathog 2023; 19:e1011527. [PMID: 37523399 PMCID: PMC10414592 DOI: 10.1371/journal.ppat.1011527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/10/2023] [Accepted: 07/02/2023] [Indexed: 08/02/2023] Open
Abstract
Members of the spotted fever group rickettsia express four large, surface-exposed autotransporters, at least one of which is a known virulence determinant. Autotransporter translocation to the bacterial outer surface, also known as type V secretion, involves formation of a β-barrel autotransporter domain in the periplasm that inserts into the outer membrane to form a pore through which the N-terminal passenger domain is passed and exposed on the outer surface. Two major surface antigens of Rickettsia rickettsii, are known to be surface exposed and the passenger domain cleaved from the autotransporter domain. A highly passaged strain of R. rickettsii, Iowa, fails to cleave these autotransporters and is avirulent. We have identified a putative peptidase, truncated in the Iowa strain, that when reconstituted into Iowa restores appropriate processing of the autotransporters as well as restoring a modest degree of virulence.
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Affiliation(s)
- Adam M. Nock
- Host-Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Karin Aistleitner
- Host-Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Tina R. Clark
- Host-Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Dan Sturdevant
- Genomics Research Section, Research Technologies Branch, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Stacy Ricklefs
- Genomics Research Section, Research Technologies Branch, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Kimmo Virtaneva
- Genomics Research Section, Research Technologies Branch, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Yixiang Zhang
- Protein Chemistry Unit, Research Technologies Branch, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Naila Gulzar
- Integrated Data Sciences Section, Research Technologies Branch, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Neelam Redekar
- Integrated Data Sciences Section, Research Technologies Branch, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Amitiva Roy
- Bioinformatics and Computational Biology Branch, Office of Cyber Infrastructure and Computational Biology, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Ted Hackstadt
- Host-Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
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5
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Beriotto I, Icke C, Sevastsyanovich YR, Rossiter AE, Romagnoli G, Savino S, Hodges FJ, Cole JA, Saul A, MacLennan CA, Cunningham AF, Micoli F, Henderson IR. Efficient Autotransporter-Mediated Extracellular Secretion of a Heterologous Recombinant Protein by Escherichia coli. Microbiol Spectr 2023; 11:e0359422. [PMID: 37036352 PMCID: PMC10269718 DOI: 10.1128/spectrum.03594-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 03/20/2023] [Indexed: 04/11/2023] Open
Abstract
The autotransporter protein secretion system has been used previously to target the secretion of heterologous proteins to the bacterial cell surface and the extracellular milieu at the laboratory scale. The platform is of particular interest for the production of "difficult" recombinant proteins that might cause toxic effects when produced intracellularly. One such protein is IrmA. IrmA is a vaccine candidate that is produced in inclusion bodies requiring refolding. Here, we describe the use and scale-up of the autotransporter system for the secretion of an industrially relevant protein (IrmA). A plasmid expressing IrmA was constructed such that the autotransporter platform could secrete IrmA into the culture supernatant fraction. The autotransporter platform was suitable for the production and purification of IrmA with comparable physical properties to the protein produced in the cytoplasm. The production of IrmA was translated to scale-up protein production conditions resulting in a yield of 29.3 mg/L of IrmA from the culture supernatant, which is consistent with yields of current industrial processes. IMPORTANCE Recombinant protein production is an essential component of the biotechnology sector. Here, we show that the autotransporter platform is a viable method for the recombinant production, secretion, and purification of a "difficult" to produce protein on an industrially relevant scale. Use of the autotransporter platform could reduce the number of downstream processing operations required, thus accelerating the development time and reducing costs for recombinant protein production.
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Affiliation(s)
- Irene Beriotto
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
- GSK Vaccines Institute for Global Health Srl, Siena, Italy
| | - Christopher Icke
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | | | - Amanda E. Rossiter
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | | | - Silvana Savino
- GSK Vaccines Institute for Global Health Srl, Siena, Italy
| | - Freya J. Hodges
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Jeffrey A. Cole
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Allan Saul
- GSK Vaccines Institute for Global Health Srl, Siena, Italy
| | - Calman A. MacLennan
- GSK Vaccines Institute for Global Health Srl, Siena, Italy
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Adam F. Cunningham
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
- Institute for Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | | | - Ian R. Henderson
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
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6
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Xing Y, Clark JR, Chang JD, Chirman DM, Green S, Zulk JJ, Jelinski J, Patras KA, Maresso AW. Broad protective vaccination against systemic Escherichia coli with autotransporter antigens. PLoS Pathog 2023; 19:e1011082. [PMID: 36800400 PMCID: PMC9937491 DOI: 10.1371/journal.ppat.1011082] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 12/26/2022] [Indexed: 02/18/2023] Open
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) is the leading cause of adult life-threatening sepsis and urinary tract infections (UTI). The emergence and spread of multidrug-resistant (MDR) ExPEC strains result in a considerable amount of treatment failure and hospitalization costs, and contribute to the spread of drug resistance amongst the human microbiome. Thus, an effective vaccine against ExPEC would reduce morbidity and mortality and possibly decrease carriage in healthy or diseased populations. A comparative genomic analysis demonstrated a gene encoding an invasin-like protein, termed sinH, annotated as an autotransporter protein, shows high prevalence in various invasive ExPEC phylogroups, especially those associated with systemic bacteremia and UTI. Here, we evaluated the protective efficacy and immunogenicity of a recombinant SinH-based vaccine consisting of either domain-3 or domains-1,2, and 3 of the putative extracellular region of surface-localized SinH. Immunization of a murine host with SinH-based antigens elicited significant protection against various strains of the pandemic ExPEC sequence type 131 (ST131) as well as multiple sequence types in two distinct models of infection (colonization and bacteremia). SinH immunization also provided significant protection against ExPEC colonization in the bladder in an acute UTI model. Immunized cohorts produced significantly higher levels of vaccine-specific serum IgG and urinary IgG and IgA, findings consistent with mucosal protection. Collectively, these results demonstrate that autotransporter antigens such as SinH may constitute promising ExPEC phylogroup-specific and sequence-type effective vaccine targets that reduce E. coli colonization and virulence.
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Affiliation(s)
- Yikun Xing
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, United States of America
| | - Justin R. Clark
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, United States of America
| | - James D. Chang
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, United States of America
| | - Dylan M. Chirman
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, United States of America
| | - Sabrina Green
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jacob J. Zulk
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, United States of America
| | - Joseph Jelinski
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kathryn A. Patras
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Alkek Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, Texas, United States of America
| | - Anthony W. Maresso
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- TAILOR Labs, Vaccine Development Group, Baylor College of Medicine, Houston, Texas, United States of America
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Qin J, Hong Y, Morona R, Totsika M. Cysteine-Dependent Conformational Heterogeneity of Shigella flexneri Autotransporter IcsA and Implications of Its Function. Microbiol Spectr 2022; 10:e0341022. [PMID: 36374106 PMCID: PMC9769942 DOI: 10.1128/spectrum.03410-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/30/2022] [Indexed: 11/16/2022] Open
Abstract
Shigella IcsA is a versatile surface virulence factor required for early and late pathogenesis stages extracellularly and intracellularly. Despite IcsA serving as a model Type V secretion system (T5SS) autotransporter to study host-pathogen interactions, its detailed molecular architecture is poorly understood. Recently, IcsA was found to switch to a different conformation for its adhesin activity upon sensing the host stimuli by Shigella Type III secretion system (T3SS). Here, we reported that the single cysteine residue (C130) near the N terminus of the IcsA passenger had a role in IcsA adhesin activity. We also showed that the IcsA passenger (IcsAp) existed in multiple conformations, and the conformation populations were influenced by a central pair of cysteine residues (C375 and C379), which was not previously reported for any Type V autotransporter passengers. Disruption of either or both central cysteine residues altered the exposure of IcsA epitopes to polyclonal anti-IcsA antibodies previously shown to block Shigella adherence, yet without loss of IcsA intracellular functions in actin-based motility (ABM). Anti-IcsA antibody reactivity was restored when the IcsA-paired cysteine substitution mutants were expressed in an ΔipaD background with a constitutively active T3SS, highlighting an interplay between T3SS and T5SS. The work here uncovered a novel molecular switch empowered by a centrally localized, short-spaced cysteine pair in the Type V autotransporter IcsA that ensured conformational heterogeneity to aid IcsA evasion of host immunity. IMPORTANCE Shigella species are the leading cause of diarrheal-related death globally by causing bacillary dysentery. The surface virulence factor IcsA, which is essential for Shigella pathogenesis, is a unique multifunctional autotransporter that is responsible for cell adhesion, and actin-based motility, yet detailed mechanistic understanding is lacking. Here, we showed that the three cysteine residues in IcsA contributed to the protein's distinct functions. The N-terminal cysteine residue within the IcsA passenger domain played a role in adhesin function, while a centrally localized cysteine pair provided conformational heterogeneity that resulted in IcsA molecules with different reactivity to adhesion-blocking anti-IcsA antibodies. In synergy with the Type III secretion system, this molecular switch preserved biological function in distinct IcsA conformations for cell adhesion, actin-based motility, and autophagy escape, providing a potential strategy by which Shigella evades host immunity and targets this essential virulence factor.
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Affiliation(s)
- Jilong Qin
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Yaoqin Hong
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Renato Morona
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Makrina Totsika
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
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Clarke KR, Hor L, Pilapitiya A, Luirink J, Paxman JJ, Heras B. Phylogenetic Classification and Functional Review of Autotransporters. Front Immunol 2022; 13:921272. [PMID: 35860281 PMCID: PMC9289746 DOI: 10.3389/fimmu.2022.921272] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/06/2022] [Indexed: 11/30/2022] Open
Abstract
Autotransporters are the core component of a molecular nano-machine that delivers cargo proteins across the outer membrane of Gram-negative bacteria. Part of the type V secretion system, this large family of proteins play a central role in controlling bacterial interactions with their environment by promoting adhesion to surfaces, biofilm formation, host colonization and invasion as well as cytotoxicity and immunomodulation. As such, autotransporters are key facilitators of fitness and pathogenesis and enable co-operation or competition with other bacteria. Recent years have witnessed a dramatic increase in the number of autotransporter sequences reported and a steady rise in functional studies, which further link these proteins to multiple virulence phenotypes. In this review we provide an overview of our current knowledge on classical autotransporter proteins, the archetype of this protein superfamily. We also carry out a phylogenetic analysis of their functional domains and present a new classification system for this exquisitely diverse group of bacterial proteins. The sixteen phylogenetic divisions identified establish sensible relationships between well characterized autotransporters and inform structural and functional predictions of uncharacterized proteins, which may guide future research aimed at addressing multiple unanswered aspects in this group of therapeutically important bacterial factors.
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Affiliation(s)
- Kaitlin R. Clarke
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Lilian Hor
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Akila Pilapitiya
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Joen Luirink
- Department of Molecular Microbiology, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit, Amsterdam, Netherlands
| | - Jason J. Paxman
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
- *Correspondence: Begoña Heras, ; Jason J. Paxman,
| | - Begoña Heras
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
- *Correspondence: Begoña Heras, ; Jason J. Paxman,
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9
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Dhillon A, Deme JC, Furlong E, Roem D, Jongerius I, Johnson S, Lea SM. Molecular Basis for Bordetella pertussis Interference with Complement, Coagulation, Fibrinolytic, and Contact Activation Systems: the Cryo-EM Structure of the Vag8-C1 Inhibitor Complex. mBio 2021; 12:e02823-20. [PMID: 33758081 PMCID: PMC8092270 DOI: 10.1128/mbio.02823-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 02/18/2021] [Indexed: 12/27/2022] Open
Abstract
Complement, contact activation, coagulation, and fibrinolysis are serum protein cascades that need strict regulation to maintain human health. Serum glycoprotein, a C1 inhibitor (C1-INH), is a key regulator (inhibitor) of serine proteases of all the above-mentioned pathways. Recently, an autotransporter protein, virulence-associated gene 8 (Vag8), produced by the whooping cough pathogen, Bordetella pertussis, was shown to bind to C1-INH and interfere with its function. Here, we present the structure of the Vag8-C1-INH complex determined using cryo-electron microscopy at a 3.6-Å resolution. The structure shows a unique mechanism of C1-INH inhibition not employed by other pathogens, where Vag8 sequesters the reactive center loop of C1-INH, preventing its interaction with the target proteases.IMPORTANCE The structure of a 10-kDa protein complex is one of the smallest to be determined using cryo-electron microscopy at high resolution. The structure reveals that C1-INH is sequestered in an inactivated state by burial of the reactive center loop in Vag8. By so doing, the bacterium is able to simultaneously perturb the many pathways regulated by C1-INH. Virulence mechanisms such as the one described here assume more importance given the emerging evidence about dysregulation of contact activation, coagulation, and fibrinolysis leading to COVID-19 pneumonia.
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Affiliation(s)
- Arun Dhillon
- Sir William Dunn School of Pathology, Oxford, United Kingdom
| | - Justin C Deme
- Sir William Dunn School of Pathology, Oxford, United Kingdom
- Central Oxford Structural Molecular Imaging Centre, Oxford, United Kingdom
| | - Emily Furlong
- Sir William Dunn School of Pathology, Oxford, United Kingdom
| | - Dorina Roem
- Sanquin Research, Department of Immunopathology, and Landsteiner Laboratory, Amsterdam University Medical Centre, Amsterdam Infection and Immunity Institute, Amsterdam, the Netherlands
| | - Ilse Jongerius
- Sanquin Research, Department of Immunopathology, and Landsteiner Laboratory, Amsterdam University Medical Centre, Amsterdam Infection and Immunity Institute, Amsterdam, the Netherlands
- Department of Pediatric Immunology, Rheumatology, and Infectious Diseases, Emma Children's Hospital, Amsterdam University Medical Centre, Amsterdam, the Netherlands
| | - Steven Johnson
- Sir William Dunn School of Pathology, Oxford, United Kingdom
| | - Susan M Lea
- Sir William Dunn School of Pathology, Oxford, United Kingdom
- Central Oxford Structural Molecular Imaging Centre, Oxford, United Kingdom
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10
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Pimenta AI, Mil‐Homens D, Fialho AM. Burkholderia cenocepacia-host cell contact controls the transcription activity of the trimeric autotransporter adhesin BCAM2418 gene. Microbiologyopen 2020; 9:e998. [PMID: 32097539 PMCID: PMC7142374 DOI: 10.1002/mbo3.998] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/02/2020] [Accepted: 01/04/2020] [Indexed: 12/11/2022] Open
Abstract
Cell-to-cell early contact between pathogens and their host cells is required for the establishment of many infections. Among various surface factors produced by bacteria that allow an organism to become established in a host, the class of adhesins is a primary determinant. Burkholderia cenocepacia adheres to the respiratory epithelium of cystic fibrosis patients and causes chronic inflammation and disease. Cell-to-cell contacts are promoted by various kinds of adhesins, including trimeric autotransporter adhesins (TAAs). We observed that among the 7 TAA genes found in the B. cenocepacia K56-2 genome, two of them (BCAM2418 and BCAS0236) express higher levels of mRNA following physical contact with host cells. Further analysis revealed that the B. cenocepacia K56-2 BCAM2418 gene shows an on-off switch after an initial colonization period, exhibits a strong expression dependent on the host cell type, and enhances its function on cell adhesion. Furthermore, our analysis revealed that adhesion to mucin-coated surfaces dramatically increases the expression levels of BCAM2418. Abrogation of mucin O-glycans turns BCAM2418 gene expression off and impairs bacterial adherence. Overall, our findings suggest that glycosylated extracellular components of host membrane might be a binding site for B. cenocepacia and a signal for the differential expression of the TAA gene BCAM2418.
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Affiliation(s)
- Andreia I. Pimenta
- iBB‐Institute for Bioengineering and BiosciencesInstituto Superior Técnico, University of LisbonLisbonPortugal
| | - Dalila Mil‐Homens
- iBB‐Institute for Bioengineering and BiosciencesInstituto Superior Técnico, University of LisbonLisbonPortugal
| | - Arsenio M. Fialho
- iBB‐Institute for Bioengineering and BiosciencesInstituto Superior Técnico, University of LisbonLisbonPortugal
- Department of BioengineeringInstituto Superior TécnicoUniversity of LisbonLisbonPortugal
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11
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Brothers KM, Callaghan JD, Stella NA, Bachinsky JM, AlHigaylan M, Lehner KL, Franks JM, Lathrop KL, Collins E, Schmitt DM, Horzempa J, Shanks RMQ. Blowing epithelial cell bubbles with GumB: ShlA-family pore-forming toxins induce blebbing and rapid cellular death in corneal epithelial cells. PLoS Pathog 2019; 15:e1007825. [PMID: 31220184 PMCID: PMC6586354 DOI: 10.1371/journal.ppat.1007825] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 05/07/2019] [Indexed: 12/18/2022] Open
Abstract
Medical devices, such as contact lenses, bring bacteria in direct contact with human cells. Consequences of these host-pathogen interactions include the alteration of mammalian cell surface architecture and induction of cellular death that renders tissues more susceptible to infection. Gram-negative bacteria known to induce cellular blebbing by mammalian cells, Pseudomonas and Vibrio species, do so through a type III secretion system-dependent mechanism. This study demonstrates that a subset of bacteria from the Enterobacteriaceae bacterial family induce cellular death and membrane blebs in a variety of cell types via a type V secretion-system dependent mechanism. Here, we report that ShlA-family cytolysins from Proteus mirabilis and Serratia marcescens were required to induce membrane blebbling and cell death. Blebbing and cellular death were blocked by an antioxidant and RIP-1 and MLKL inhibitors, implicating necroptosis in the observed phenotypes. Additional genetic studies determined that an IgaA family stress-response protein, GumB, was necessary to induce blebs. Data supported a model where GumB and shlBA are in a regulatory circuit through the Rcs stress response phosphorelay system required for bleb formation and pathogenesis in an invertebrate model of infection and proliferation in a phagocytic cell line. This study introduces GumB as a regulator of S. marcescens host-pathogen interactions and demonstrates a common type V secretion system-dependent mechanism by which bacteria elicit surface morphological changes on mammalian cells. This type V secretion-system mechanism likely contributes bacterial damage to the corneal epithelial layer, and enables access to deeper parts of the tissue that are more susceptible to infection.
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Affiliation(s)
- Kimberly M. Brothers
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA United States of America
- Charles T. Campbell Laboratory of Ophthalmic Microbiology
| | - Jake D. Callaghan
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA United States of America
- Charles T. Campbell Laboratory of Ophthalmic Microbiology
| | - Nicholas A. Stella
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA United States of America
- Charles T. Campbell Laboratory of Ophthalmic Microbiology
| | - Julianna M. Bachinsky
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA United States of America
- Charles T. Campbell Laboratory of Ophthalmic Microbiology
| | - Mohammed AlHigaylan
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA United States of America
- Charles T. Campbell Laboratory of Ophthalmic Microbiology
| | - Kara L. Lehner
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA United States of America
- Charles T. Campbell Laboratory of Ophthalmic Microbiology
| | - Jonathan M. Franks
- Center for Biological Imaging, University of Pittsburgh, Pittsburgh, PA United States of America
| | - Kira L. Lathrop
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA United States of America
| | - Elliot Collins
- Department of Natural Sciences and Mathematics, West Liberty University, West Liberty, WV United States of America
| | - Deanna M. Schmitt
- Department of Natural Sciences and Mathematics, West Liberty University, West Liberty, WV United States of America
| | - Joseph Horzempa
- Department of Natural Sciences and Mathematics, West Liberty University, West Liberty, WV United States of America
| | - Robert M. Q. Shanks
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA United States of America
- Charles T. Campbell Laboratory of Ophthalmic Microbiology
- * E-mail:
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12
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Battaglioli EJ, Goh KGK, Atruktsang TS, Schwartz K, Schembri MA, Welch RA. Identification and Characterization of a Phase-Variable Element That Regulates the Autotransporter UpaE in Uropathogenic Escherichia coli. mBio 2018; 9:e01360-18. [PMID: 30087170 PMCID: PMC6083910 DOI: 10.1128/mbio.01360-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 06/28/2018] [Indexed: 12/15/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is the most common etiologic agent of uncomplicated urinary tract infection (UTI). An important mechanism of gene regulation in UPEC is phase variation that involves inversion of a promoter-containing DNA element via enzymatic activity of tyrosine recombinases, resulting in biphasic, ON or OFF expression of target genes. The UPEC reference strain CFT073 has five tyrosine site-specific recombinases that function at two previously characterized promoter inversion systems, fimS and hyxS Three of the five recombinases are located proximally to their cognate target elements, which is typical of promoter inversion systems. The genes for the other two recombinases, IpuA and IpuB, are located distal from these sites. Here, we identified and characterized a third phase-variable invertible element in CFT073, ipuS, located proximal to ipuA and ipuB The inversion of ipuS is catalyzed by four of the five CFT073 recombinases. Orientation of the element drives transcription of a two-gene operon containing ipuR, a predicted LuxR-type regulator, and upaE, a predicted autotransporter. We show that the predicted autotransporter UpaE is surface located and facilitates biofilm formation as well as adhesion to extracellular matrix proteins in a K-12 recombinant background. Consistent with this phenotype, the ipuS ON condition in CFT073 results in defective swimming motility, increased adherence to human kidney epithelial cells, and a positive competitive kidney colonization advantage in experimental mouse UTIs. Overall, the identification of a third phase switch in UPEC that is regulated by a shared set of recombinases describes a complex phase-variable virulence network in UPEC.IMPORTANCE Uropathogenic Escherichia coli (UPEC) is the most common cause of urinary tract infection (UTI). ON versus OFF phase switching by inversion of small DNA elements at two chromosome sites in UPEC regulates the expression of important virulence factors, including the type 1 fimbria adhesion organelle. In this report, we describe a third invertible element, ipuS, in the UPEC reference strain CFT073. The inversion of ipuS controls the phase-variable expression of upaE, an autotransporter gene that encodes a surface protein involved in adherence to extracellular matrix proteins and colonization of the kidneys in a murine model of UTI.
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Affiliation(s)
- E J Battaglioli
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medicine, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - K G K Goh
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - T S Atruktsang
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - K Schwartz
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - M A Schembri
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - R A Welch
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Martinez-Gil M, Goh KGK, Rackaityte E, Sakamoto C, Audrain B, Moriel DG, Totsika M, Ghigo JM, Schembri MA, Beloin C. YeeJ is an inverse autotransporter from Escherichia coli that binds to peptidoglycan and promotes biofilm formation. Sci Rep 2017; 7:11326. [PMID: 28900103 PMCID: PMC5595812 DOI: 10.1038/s41598-017-10902-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/16/2017] [Indexed: 02/08/2023] Open
Abstract
Escherichia coli is a commensal or pathogenic bacterium that can survive in diverse environments. Adhesion to surfaces is essential for E. coli colonization, and thus it is important to understand the molecular mechanisms that promote this process in different niches. Autotransporter proteins are a class of cell-surface factor used by E. coli for adherence. Here we characterized the regulation and function of YeeJ, a poorly studied but widespread representative from an emerging class of autotransporter proteins, the inverse autotransporters (IAT). We showed that the yeeJ gene is present in ~40% of 96 completely sequenced E. coli genomes and that YeeJ exists as two length variants, albeit with no detectable functional differences. We demonstrated that YeeJ promotes biofilm formation in different settings through exposition at the cell-surface. We also showed that YeeJ contains a LysM domain that interacts with peptidoglycan and thus assists its localization into the outer membrane. Additionally, we identified the Polynucleotide Phosphorylase PNPase as a repressor of yeeJ transcription. Overall, our work provides new insight into YeeJ as a member of the recently defined IAT class, and contributes to our understanding of how commensal and pathogenic E. coli colonise their environments.
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Affiliation(s)
- Marta Martinez-Gil
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France
- Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias. Universidad de Málaga, Málaga, Spain
| | - Kelvin G K Goh
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Elze Rackaityte
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France
- University of California San Francisco, Department of Medicine, San Francisco, CA, USA
| | - Chizuko Sakamoto
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France
| | - Bianca Audrain
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France
| | - Danilo G Moriel
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
- GSK Vaccines Institute for Global Health S.r.l., 53100, Siena, Italy
| | - Makrina Totsika
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia
- Institute of Health and Biomedical Innovation, and School of Biomedical Sciences, Queensland University of Technology, Kelvin Grove, QLD, 4059, Australia
| | - Jean-Marc Ghigo
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France
| | - Mark A Schembri
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia.
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Christophe Beloin
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux, 75724, Paris, CEDEX 15, France.
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14
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Ragunath C, DiFranco K, Shanmugam M, Gopal P, Vyas V, Fine DH, Cugini C, Ramasubbu N. Surface display of Aggregatibacter actinomycetemcomitans autotransporter Aae and dispersin B hybrid act as antibiofilm agents. Mol Oral Microbiol 2016; 31:329-39. [PMID: 26280561 PMCID: PMC6118125 DOI: 10.1111/omi.12126] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2015] [Indexed: 11/30/2022]
Abstract
Among the various proteins expressed by the periodontopathogen Aggregatibacter actinomycetemcomitans, two proteins play important roles for survival in the oral cavity. The autotransporter Aae facilitates the attachment of the pathogen to oral epithelial cells, which act as a reservoir, while the biofilm-degrading glycoside hydrolase dispersin B facilitates the movement of daughter cells from the mature biofilm to a new site. The objective of this study was to use the potential of these two proteins to control biofilms. To this end, we generated a hybrid construct between the Aae C-terminal translocating domain and dispersin B, and mobilized it into Escherichia coli Rosetta (DE3) pLysS cells. Immunofluorescence analysis of the modified E. coli cells confirmed the presence of dispersin B on the surface. Further, the membrane localization of the displayed dispersin B was confirmed with Western blot analysis. The integrity of the E. coli cells displaying the dispersin B was confirmed through FACS analysis. The hydrolytic activity of the surface-displayed dispersin B was confirmed by using 4-methylumbelliferyl-β-d-glucopyranoside as the substrate. The detachment ability of the dispersin B surface-displaying E. coli cells was shown using Staphylococcus epidermidis and Actinobacillus pleuropneumoniae biofilms in a microtiter assay. We concluded that the Aae β-domain is sufficient to translocate foreign enzymes in the native folded form and that the method of Aae-mediated translocation of surface displayed enzymes might be useful for control of biofilms.
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Affiliation(s)
| | | | - Mayilvahanan Shanmugam
- Department of Oral Biology, Rutgers School of Dental Medicine, 185 South Orange Ave, Newark NJ 07103, USA
| | - Prerna Gopal
- Department of Oral Biology, Rutgers School of Dental Medicine, 185 South Orange Ave, Newark NJ 07103, USA
| | - Vishal Vyas
- Department of Oral Biology, Rutgers School of Dental Medicine, 185 South Orange Ave, Newark NJ 07103, USA
| | - Daniel H. Fine
- Department of Oral Biology, Rutgers School of Dental Medicine, 185 South Orange Ave, Newark NJ 07103, USA
| | - Carla Cugini
- Department of Oral Biology, Rutgers School of Dental Medicine, 185 South Orange Ave, Newark NJ 07103, USA
| | - Narayanan Ramasubbu
- Department of Oral Biology, Rutgers School of Dental Medicine, 185 South Orange Ave, Newark NJ 07103, USA
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15
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Zhao Y, Wang S, Yang D, Liu X, Han X, Tian M, Ding C, Liu Z, Yu S. [Vacuolating autotransporter toxin affects biological characteristics and pathogenicity of avian pathogenic Escherichia coli]. Wei Sheng Wu Xue Bao 2015; 55:1208-1214. [PMID: 26762034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To determined the role of vacuolating autotransporter toxin (vat) gene in avian pathogenic Escherichia coli (APEC), we detected the biological characteristics and pathogenicity of vat gene mutant strain of APEC-O1. METHODS We constructed the vat mutant and complementary strain of APEC-O1 by the Red recombination system and plasmid pSTV28. Then we compared the growth curve, motility, agglutination, biofilm formation and pathogenicity of mutant strain, wild-type strain and complementary strain. RESULTS The vat mutant did not affect the growth and resistance to environment stress of APEC. However, inactivation of APEC-O1 vat gene resulted in enhanced motility, diminished agglutination, decreased biofilm formation and attenuated virulence in ducks. CONCLUSION These data indicated that Vat affect the motility, agglutination, biofilm formation and virulence of APEC-O1, which help us to understand the role of the Vat in the APEC pathogenicity.
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16
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Zimmerman SM, Michel F, Hogan RJ, Lafontaine ER. The Autotransporter BpaB Contributes to the Virulence of Burkholderia mallei in an Aerosol Model of Infection. PLoS One 2015; 10:e0126437. [PMID: 25993100 PMCID: PMC4438868 DOI: 10.1371/journal.pone.0126437] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/02/2015] [Indexed: 02/06/2023] Open
Abstract
Burkholderia mallei is a highly pathogenic bacterium that causes the zoonosis glanders. Previous studies indicated that the genome of the organism contains eight genes specifying autotransporter proteins, which are important virulence factors of Gram-negative bacteria. In the present study, we report the characterization of one of these autotransporters, BpaB. Database searches identified the bpaB gene in ten B. mallei isolates and the predicted proteins were 99-100% identical. Comparative sequence analyses indicate that the gene product is a trimeric autotransporter of 1,090 amino acids with a predicted molecular weight of 105-kDa. Consistent with this finding, we discovered that recombinant bacteria expressing bpaB produce a protein of ≥300-kDa on their surface that is reactive with a BpaB-specific monoclonal antibody. Analysis of sera from mice infected with B. mallei indicated that animals produce antibodies against BpaB during the course of disease, thus establishing production of the autotransporter in vivo. To gain insight on its role in virulence, we inactivated the bpaB gene of B. mallei strain ATCC 23344 and determined the median lethal dose of the mutant in a mouse model of aerosol infection. These experiments revealed that the bpaB mutation attenuates virulence 8-14 fold. Using a crystal violet-based assay, we also discovered that constitutive production of BpaB on the surface of B. mallei promotes biofilm formation. To our knowledge, this is the first report of a biofilm factor for this organism.
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Affiliation(s)
- Shawn M. Zimmerman
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, United States of America
| | - Frank Michel
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia College of Veterinary Medicine, Athens, GA, United States of America
| | - Robert J. Hogan
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, United States of America
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia College of Veterinary Medicine, Athens, GA, United States of America
| | - Eric R. Lafontaine
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, United States of America
- * E-mail:
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17
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Adler NRL, Stevens MP, Dean RE, Saint RJ, Pankhania D, Prior JL, Atkins TP, Kessler B, Nithichanon A, Lertmemongkolchai G, Galyov EE. Systematic mutagenesis of genes encoding predicted autotransported proteins of Burkholderia pseudomallei identifies factors mediating virulence in mice, net intracellular replication and a novel protein conferring serum resistance. PLoS One 2015; 10:e0121271. [PMID: 25830295 PMCID: PMC4382181 DOI: 10.1371/journal.pone.0121271] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 01/29/2015] [Indexed: 01/12/2023] Open
Abstract
Burkholderia pseudomallei is the causative agent of the severe tropical disease melioidosis, which commonly presents as sepsis. The B. pseudomallei K96243 genome encodes eleven predicted autotransporters, a diverse family of secreted and outer membrane proteins often associated with virulence. In a systematic study of these autotransporters, we constructed insertion mutants in each gene predicted to encode an autotransporter and assessed them for three pathogenesis-associated phenotypes: virulence in the BALB/c intra-peritoneal mouse melioidosis model, net intracellular replication in J774.2 murine macrophage-like cells and survival in 45% (v/v) normal human serum. From the complete repertoire of eleven autotransporter mutants, we identified eight mutants which exhibited an increase in median lethal dose of 1 to 2-log10 compared to the isogenic parent strain (bcaA, boaA, boaB, bpaA, bpaC, bpaE, bpaF and bimA). Four mutants, all demonstrating attenuation for virulence, exhibited reduced net intracellular replication in J774.2 macrophage-like cells (bimA, boaB, bpaC and bpaE). A single mutant (bpaC) was identified that exhibited significantly reduced serum survival compared to wild-type. The bpaC mutant, which demonstrated attenuation for virulence and net intracellular replication, was sensitive to complement-mediated killing via the classical and/or lectin pathway. Serum resistance was rescued by in trans complementation. Subsequently, we expressed recombinant proteins of the passenger domain of four predicted autotransporters representing each of the phenotypic groups identified: those attenuated for virulence (BcaA), those attenuated for virulence and net intracellular replication (BpaE), the BpaC mutant with defects in virulence, net intracellular replication and serum resistance and those displaying wild-type phenotypes (BatA). Only BcaA and BpaE elicited a strong IFN-γ response in a restimulation assay using whole blood from seropositive donors and were recognised by seropositive human sera from the endemic area. To conclude, several predicted autotransporters contribute to B. pseudomallei virulence and BpaC may do so by conferring resistance against complement-mediated killing.
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Affiliation(s)
- Natalie R. Lazar Adler
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Mark P. Stevens
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, United Kingdom
| | - Rachel E. Dean
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
| | - Richard J. Saint
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
| | - Depesh Pankhania
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Joann L. Prior
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
| | - Timothy P. Atkins
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
- School of Biosciences, Geoffrey Pope Building, University of Exeter, Exeter, United Kingdom
| | - Bianca Kessler
- The Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Arnone Nithichanon
- The Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Ganjana Lertmemongkolchai
- The Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Edouard E. Galyov
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
- * E-mail:
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18
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Riaz MR, Siddiqi AR, Bokhari H. Structural and functional studies of BapC protein of Bordetella pertussis. Microbiol Res 2015; 174:56-61. [PMID: 25946329 DOI: 10.1016/j.micres.2015.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 03/09/2015] [Accepted: 03/11/2015] [Indexed: 11/18/2022]
Abstract
Bordetella pertussis, the causative agent of whooping cough, attaches to mucosal surface in upper respiratory tract, where it produces a variety of surface associated and secreted autotransporter molecules among others. In this study we have cloned newly identified member of autotransporter family BapC (B. pertussis autotransporter protein C); expressed it in Escherichia coli and characterized it for its different properties. We have also raised antisera to BapC protein; the antisera were used in immunofluorescence assay to determine the surface association of the protein. Results suggest that BapC in B. pertussis Taberman parent is surface exposed when compared with the respective BapC mutant. The neutralizing effect of anti-BapC serum was also evaluated in the presence of active complement proteins and results suggest that antiserum can potentiate the killing of B. pertussis cells in the presence of added source of complement. Structure of the protein was also studied, both α and β domains of the protein were modeled, β domain exhibits typical transmembrane β-barrel porin topology whereas α domain behaves as a characteristic bacterial autotransporter passenger domain.
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Affiliation(s)
- Muhammad Rizwan Riaz
- Department of Biosciences, COMSATS Institute of Information Technology, Chak Shazad Campus, Islamabad, Pakistan.
| | - Abdul Rauf Siddiqi
- Department of Biosciences, COMSATS Institute of Information Technology, Chak Shazad Campus, Islamabad, Pakistan.
| | - Habib Bokhari
- Department of Biosciences, COMSATS Institute of Information Technology, Chak Shazad Campus, Islamabad, Pakistan.
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