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Navarro-Garcia F. Serine proteases autotransporter of Enterobacteriaceae: Structures, subdomains, motifs, functions, and targets. Mol Microbiol 2023; 120:178-193. [PMID: 37392318 DOI: 10.1111/mmi.15116] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 07/03/2023]
Abstract
Serine protease autotransporters of Enterobacteriaceae (SPATE) constitute a superfamily of virulence factors, resembling the trypsin-like superfamily of serine proteases. SPATEs accomplish multiple functions associated to disease development of their hosts, which could be the consequence of SPATE cleavage of host cell components. SPATEs have been divided into class-1 and class-2 based on structural differences and biological effects, including similar substrate specificity, cytotoxic effects on cultured cells, and enterotoxin activity on intestinal tissues for class-1 SPATEs, whereas most class-2 SPATEs exhibit a lectin-like activity with a predilection to degrade a variety of mucins, including leukocyte surface O-glycoproteins and soluble host proteins, resulting in mucosal colonization and immune modulation. In this review, the structure of class-1 and class-2 are analyzed, making emphasis on their putative functional subdomains as well as a description of their function is provided, including prototypical mechanism of action.
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Affiliation(s)
- Fernando Navarro-Garcia
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del IPN, Mexico, Mexico
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2
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In vivo studies on Citrobacter rodentium and host cell death pathways. Curr Opin Microbiol 2021; 64:60-67. [PMID: 34601305 DOI: 10.1016/j.mib.2021.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 12/29/2022]
Abstract
Citrobacter rodentium is a mouse-specific extracellular enteropathogen, commonly used as a small animal model for studying human enteropathogenic Escherichia coli infections. Both pathogens share a core set of virulence factors, including a type III secretion system, which enables translocation of effector proteins into infected cells to subvert host antimicrobial responses. Notably, these bacterial effectors have been reported to specifically target components of the apoptotic, necroptotic and pyroptotic signaling cascades in vivo, resulting in compromised immune cell recruitment and impaired mucosal homeostasis. Identifying the contributions of each cell death modality to bacterial control in a physiological model represents a crucial step in furthering our understanding of host-pathogen evolution and may provide insight into the host evasion strategies utilised by other enteric pathogens.
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Comparative Pathogenomics of Escherichia coli: Polyvalent Vaccine Target Identification through Virulome Analysis. Infect Immun 2021; 89:e0011521. [PMID: 33941580 PMCID: PMC8281228 DOI: 10.1128/iai.00115-21] [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] [Indexed: 02/07/2023] Open
Abstract
Comparative genomics of bacterial pathogens has been useful for revealing potential virulence factors. Escherichia coli is a significant cause of human morbidity and mortality worldwide but can also exist as a commensal in the human gastrointestinal tract. With many sequenced genomes, it has served as a model organism for comparative genomic studies to understand the link between genetic content and potential for virulence. To date, however, no comprehensive analysis of its complete “virulome” has been performed for the purpose of identifying universal or pathotype-specific targets for vaccine development. Here, we describe the construction of a pathotype database of 107 well-characterized completely sequenced pathogenic and nonpathogenic E. coli strains, which we annotated for major virulence factors (VFs). The data are cross referenced for patterns against pathotype, phylogroup, and sequence type, and the results were verified against all 1,348 complete E. coli chromosomes in the NCBI RefSeq database. Our results demonstrate that phylogroup drives many of the “pathotype-associated” VFs, and ExPEC-associated VFs are found predominantly within the B2/D/F/G phylogenetic clade, suggesting that these phylogroups are better adapted to infect human hosts. Finally, we used this information to propose polyvalent vaccine targets with specificity toward extraintestinal strains, targeting key invasive strategies, including immune evasion (group 2 capsule), iron acquisition (FyuA, IutA, and Sit), adherence (SinH, Afa, Pap, Sfa, and Iha), and toxins (Usp, Sat, Vat, Cdt, Cnf1, and HlyA). While many of these targets have been proposed before, this work is the first to examine their pathotype and phylogroup distribution and how they may be targeted together to prevent disease.
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4
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Badamchi A, Bahrami F, Tasbiti AH, Yari S, Shafiei M, Shahcheraghi F, Siadat SD. Immuno-proteomics analysis between OMV of vaccine and dominant wild type strains of Bordetella pertussis in Iran. IRANIAN JOURNAL OF MICROBIOLOGY 2020; 12:77-88. [PMID: 32494341 PMCID: PMC7244817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Despite widespread vaccination programs against pertussis, there has been a worldwide resurgence of the disease in recent years. We aimed to investigate protein composition of outer membrane vesicles (OMV) of Bordetella pertussis (Bp) and to evaluate the immunogenicity of OMV antigens both in the vaccine and the dominant wild type strains in Iran. MATERIALS AND METHODS The OMV were purified from both vaccine and wild type strains. The immunoreactivity of the OMVs was investigated by exposing sera taken from the patients and the vaccinated infants. The protein profiles of OMVs were compared using two-dimensional electrophoresis. The LC-MS/MS was used to analyse and identify differentially expressed protein spots. RESULTS The two type strains showed differences in their 2D gel protein profile. Further analysis of selected proteins from the dominant Iranian strains using LC-MS/MS demonstrated that the identified proteins fell into different functional categories including (i) metabolism, (ii) membrane transport and secretion system, (iii) biosynthesis and degradation, (iv) adaption, adhesion, pathogenicity, conserved hypothetical and protection responses. Moreover, a number of immunogenic proteins were identified including Bp 2434 (serine protease) and Bp 1616 (putative DNA binding protein) from the vaccine and the wild type strains, respectively which could be considered as potential antigens for an OMV vaccine. CONCLUSION OMV Bp could be considered as an alternative vaccine against pertussis, containing the bacterium's protein antigens that can confer equal efficacy compared to a whole bacterial cell vaccine with advantages such as less side effects and lower costs than acellular pertussis vaccines.
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Affiliation(s)
- Ali Badamchi
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
| | - Fariborz Bahrami
- Department of Immunology, Pasteur Institute of Iran, Tehran, Iran
| | | | - Shamsi Yari
- Department of Tuberculosis and Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran
| | - Morvarid Shafiei
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
| | | | - Seyed Davar Siadat
- Department of Tuberculosis and Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran
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Habouria H, Pokharel P, Maris S, Garénaux A, Bessaiah H, Houle S, Veyrier FJ, Guyomard-Rabenirina S, Talarmin A, Dozois CM. Three new serine-protease autotransporters of Enterobacteriaceae (SPATEs) from extra-intestinal pathogenic Escherichia coli and combined role of SPATEs for cytotoxicity and colonization of the mouse kidney. Virulence 2020; 10:568-587. [PMID: 31198092 PMCID: PMC6592367 DOI: 10.1080/21505594.2019.1624102] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Serine protease autotransporters of Enterobacteriaceae (SPATEs) are secreted proteins that contribute to virulence and function as proteases, toxins, adhesins, and/or immunomodulators. An extra-intestinal pathogenic E. coli (ExPEC) O1:K1 strain, QT598, isolated from a turkey, was shown to contain vat, tsh, and three uncharacterized SPATE-encoding genes. Uncharacterized SPATEs: Sha (Serine-protease hemagglutinin autotransporter), TagB and TagC (tandem autotransporter genes B and C) were tested for activities including hemagglutination, autoaggregation, and cytotoxicity when expressed in E. coli K-12. Sha and TagB conferred autoaggregation and hemagglutination activities. TagB, TagC, and Sha all exhibited cytopathic effects on a bladder epithelial cell line. In QT598, tagB and tagC are tandemly encoded on a genomic island, and were present in 10% of UTI isolates and 4.7% of avian E. coli. Sha is encoded on a virulence plasmid and was present in 1% of UTI isolates and 20% of avian E. coli. To specifically examine the role of SPATEs for infection, the 5 SPATE genes were deleted from strain QT598 and tested for cytotoxicity. Loss of all five SPATEs abrogated the cytopathic effect on bladder epithelial cells, although derivatives producing any of the 5 SPATEs retained cytopathic activity. In mouse infections, sha gene-expression was up-regulated a mean of sixfold in the bladder compared to growth in vitro. Loss of either tagBC or sha did not reduce urinary tract colonization. Deletion of all 5 SPATEs, however, significantly reduced competitive colonization of the kidney supporting a cumulative role of SPATEs for QT598 in the mouse UTI model.
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Affiliation(s)
- Hajer Habouria
- a Institut national de recherche scientifique (INRS)-Institut Armand Frappier , Laval , Quebec , Canada.,b Centre de recherche en infectiologie porcine et avicole (CRIPA)
| | - Pravil Pokharel
- a Institut national de recherche scientifique (INRS)-Institut Armand Frappier , Laval , Quebec , Canada.,b Centre de recherche en infectiologie porcine et avicole (CRIPA)
| | - Segolène Maris
- a Institut national de recherche scientifique (INRS)-Institut Armand Frappier , Laval , Quebec , Canada.,b Centre de recherche en infectiologie porcine et avicole (CRIPA)
| | - Amélie Garénaux
- a Institut national de recherche scientifique (INRS)-Institut Armand Frappier , Laval , Quebec , Canada.,b Centre de recherche en infectiologie porcine et avicole (CRIPA)
| | - Hicham Bessaiah
- a Institut national de recherche scientifique (INRS)-Institut Armand Frappier , Laval , Quebec , Canada.,b Centre de recherche en infectiologie porcine et avicole (CRIPA)
| | - Sébastien Houle
- a Institut national de recherche scientifique (INRS)-Institut Armand Frappier , Laval , Quebec , Canada.,b Centre de recherche en infectiologie porcine et avicole (CRIPA)
| | - Frédéric J Veyrier
- a Institut national de recherche scientifique (INRS)-Institut Armand Frappier , Laval , Quebec , Canada.,c Institut Pasteur International Network
| | - Stéphanie Guyomard-Rabenirina
- c Institut Pasteur International Network.,d Unité Environnement Santé , Institut Pasteur de Guadeloupe , Les Abymes , Guadeloupe , France
| | - Antoine Talarmin
- c Institut Pasteur International Network.,d Unité Environnement Santé , Institut Pasteur de Guadeloupe , Les Abymes , Guadeloupe , France
| | - Charles M Dozois
- a Institut national de recherche scientifique (INRS)-Institut Armand Frappier , Laval , Quebec , Canada.,b Centre de recherche en infectiologie porcine et avicole (CRIPA).,c Institut Pasteur International Network
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Pokharel P, Habouria H, Bessaiah H, Dozois CM. Serine Protease Autotransporters of the Enterobacteriaceae (SPATEs): Out and About and Chopping It Up. Microorganisms 2019; 7:E594. [PMID: 31766493 PMCID: PMC6956023 DOI: 10.3390/microorganisms7120594] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 11/13/2019] [Indexed: 02/06/2023] Open
Abstract
Autotransporters are secreted proteins with multiple functions produced by a variety of Gram-negative bacteria. In Enterobacteriaceae, a subgroup of these autotransporters are the SPATEs (serine protease autotransporters of Enterobacteriaceae). SPATEs play a crucial role in survival and virulence of pathogens such as Escherichia coli and Shigella spp. and contribute to intestinal and extra-intestinal infections. These high molecular weight proteases are transported to the external milieu by the type Va secretion system and function as proteases with diverse substrate specificities and biological functions including adherence and cytotoxicity. Herein, we provide an overview of SPATEs and discuss recent findings on the biological roles of these secreted proteins, including proteolysis of substrates, adherence to cells, modulation of the immune response, and virulence in host models. In closing, we highlight recent insights into the regulation of expression of SPATEs that could be exploited to understand fundamental SPATE biology.
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Affiliation(s)
- Pravil Pokharel
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (P.P.); (H.H.); (H.B.)
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Hajer Habouria
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (P.P.); (H.H.); (H.B.)
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Hicham Bessaiah
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (P.P.); (H.H.); (H.B.)
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Charles M. Dozois
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (P.P.); (H.H.); (H.B.)
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Saint-Hyacinthe, QC J2S 2M2, Canada
- Institut Pasteur International Network, Laval, QC H7V 1B7, Canada
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Attaching-and-Effacing Pathogens Exploit Junction Regulatory Activities of N-WASP and SNX9 to Disrupt the Intestinal Barrier. Cell Mol Gastroenterol Hepatol 2018. [PMID: 29675452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
BACKGROUND & AIMS Neural Wiskott-Aldrich Syndrome protein (N-WASP) is a key regulator of the actin cytoskeleton in epithelial tissues and is poised to mediate cytoskeletal-dependent aspects of apical junction complex (AJC) homeostasis. Attaching-and-effacing (AE) pathogens disrupt this homeostasis through translocation of the effector molecule early secreted antigenic target-6 (ESX)-1 secretion-associated protein F (EspF). Although the mechanisms underlying AJC disruption by EspF are unknown, EspF contains putative binding sites for N-WASP and the endocytic regulator sorting nexin 9 (SNX9). We hypothesized that N-WASP regulates AJC integrity and AE pathogens use EspF to induce junction disassembly through an N-WASP- and SNX9-dependent pathway. METHODS We analyzed mice with intestine-specific N-WASP deletion and generated cell lines with N-WASP and SNX9 depletion for dynamic functional assays. We generated EPEC and Citrobacter rodentium strains complemented with EspF bearing point mutations abolishing N-WASP and SNX9 binding to investigate the requirement for these interactions. RESULTS Mice lacking N-WASP in the intestinal epithelium showed spontaneously increased permeability, abnormal AJC morphology, and mislocalization of occludin. N-WASP depletion in epithelial cell lines led to impaired assembly and disassembly of tight junctions in response to changes in extracellular calcium. Cells lacking N-WASP or SNX9 supported actin pedestals and type III secretion, but were resistant to EPEC-induced AJC disassembly and loss of transepithelial resistance. We found that during in vivo infection with AE pathogens, EspF must bind both N-WASP and SNX9 to disrupt AJCs and induce intestinal barrier dysfunction. CONCLUSIONS Overall, these studies show that N-WASP critically regulates AJC homeostasis, and the AE pathogen effector EspF specifically exploits both N-WASP and SNX9 to disrupt intestinal barrier integrity during infection.
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Key Words
- ADF, actin depolymerization factor
- AE, attaching-and-effacing
- AJ, adherens junction
- AJC, apical junction complex
- Arp, actin-related protein
- CR, Citrobacter rodentium
- Crb, Crumbs
- Cytoskeleton
- DBS100, David B. Schauer 100
- EHEC, enterohemorrhagic Escherichia coli
- EM, electron microscopy
- EPEC, enteropathogenic Escherichia coli
- EcoRI, E. coli RY13 I
- EspF
- EspF, early secreted antigenic target-6 (ESX)-1 secretion-associated protein F
- FITC, fluorescein isothiocyanate
- Junction Regulation
- KO, knockout
- N-WASP
- N-WASP, Neural Wiskott-Aldrich Syndrome protein
- NWKD, Neural Wiskott-Aldrich Syndrome protein knockdown
- PBS, phosphate-buffered saline
- PCR, polymerase chain reaction
- SNX9, sorting nexin 9
- SNX9KD, sorting nexin 9 knockdown
- TER, transepithelial electrical resistance
- TJ, tight junction
- Tir, translocated intimin receptor
- ZO-1, zonula occludens-1
- iNWKO, intestine Neural Wiskott-Aldrich Syndrome protein knockout
- shRNA, short hairpin RNA
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8
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Garber JJ, Mallick EM, Scanlon KM, Turner JR, Donnenberg MS, Leong JM, Snapper SB. Attaching-and-Effacing Pathogens Exploit Junction Regulatory Activities of N-WASP and SNX9 to Disrupt the Intestinal Barrier. Cell Mol Gastroenterol Hepatol 2017; 5:273-288. [PMID: 29675452 PMCID: PMC5904039 DOI: 10.1016/j.jcmgh.2017.11.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 11/28/2017] [Indexed: 02/05/2023]
Abstract
BACKGROUND & AIMS Neural Wiskott-Aldrich Syndrome protein (N-WASP) is a key regulator of the actin cytoskeleton in epithelial tissues and is poised to mediate cytoskeletal-dependent aspects of apical junction complex (AJC) homeostasis. Attaching-and-effacing (AE) pathogens disrupt this homeostasis through translocation of the effector molecule early secreted antigenic target-6 (ESX)-1 secretion-associated protein F (EspF). Although the mechanisms underlying AJC disruption by EspF are unknown, EspF contains putative binding sites for N-WASP and the endocytic regulator sorting nexin 9 (SNX9). We hypothesized that N-WASP regulates AJC integrity and AE pathogens use EspF to induce junction disassembly through an N-WASP- and SNX9-dependent pathway. METHODS We analyzed mice with intestine-specific N-WASP deletion and generated cell lines with N-WASP and SNX9 depletion for dynamic functional assays. We generated EPEC and Citrobacter rodentium strains complemented with EspF bearing point mutations abolishing N-WASP and SNX9 binding to investigate the requirement for these interactions. RESULTS Mice lacking N-WASP in the intestinal epithelium showed spontaneously increased permeability, abnormal AJC morphology, and mislocalization of occludin. N-WASP depletion in epithelial cell lines led to impaired assembly and disassembly of tight junctions in response to changes in extracellular calcium. Cells lacking N-WASP or SNX9 supported actin pedestals and type III secretion, but were resistant to EPEC-induced AJC disassembly and loss of transepithelial resistance. We found that during in vivo infection with AE pathogens, EspF must bind both N-WASP and SNX9 to disrupt AJCs and induce intestinal barrier dysfunction. CONCLUSIONS Overall, these studies show that N-WASP critically regulates AJC homeostasis, and the AE pathogen effector EspF specifically exploits both N-WASP and SNX9 to disrupt intestinal barrier integrity during infection.
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Key Words
- ADF, actin depolymerization factor
- AE, attaching-and-effacing
- AJ, adherens junction
- AJC, apical junction complex
- Arp, actin-related protein
- CR, Citrobacter rodentium
- Crb, Crumbs
- Cytoskeleton
- DBS100, David B. Schauer 100
- EHEC, enterohemorrhagic Escherichia coli
- EM, electron microscopy
- EPEC, enteropathogenic Escherichia coli
- EcoRI, E. coli RY13 I
- EspF
- EspF, early secreted antigenic target-6 (ESX)-1 secretion-associated protein F
- FITC, fluorescein isothiocyanate
- Junction Regulation
- KO, knockout
- N-WASP
- N-WASP, Neural Wiskott-Aldrich Syndrome protein
- NWKD, Neural Wiskott-Aldrich Syndrome protein knockdown
- PBS, phosphate-buffered saline
- PCR, polymerase chain reaction
- SNX9, sorting nexin 9
- SNX9KD, sorting nexin 9 knockdown
- TER, transepithelial electrical resistance
- TJ, tight junction
- Tir, translocated intimin receptor
- ZO-1, zonula occludens-1
- iNWKO, intestine Neural Wiskott-Aldrich Syndrome protein knockout
- shRNA, short hairpin RNA
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Affiliation(s)
- John J. Garber
- Gastrointestinal Unit, Massachusetts General Hospital, Boston, Massachusetts,Division of Gastroenterology/Nutrition and Center for Inflammatory Bowel Disease Treatment and Research, Boston Children's Hospital, Boston, Massachusetts,Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Emily M. Mallick
- Department of Medicine Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Karen M. Scanlon
- Department of Medicine and Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Jerrold R. Turner
- Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts,Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Michael S. Donnenberg
- Department of Medicine and Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
| | - Scott B. Snapper
- Division of Gastroenterology/Nutrition and Center for Inflammatory Bowel Disease Treatment and Research, Boston Children's Hospital, Boston, Massachusetts,Division of Gastroenterology and Hepatology, Brigham and Women's Hospital, Boston, Massachusetts,Department of Medicine, Harvard Medical School, Boston, Massachusetts,Correspondence Address correspondence to: Scott B. Snapper, MD, PhD, Division of Gastroenterology/Nutrition, Boston Children’s Hospital, Enders 676, 300 Longwood Avenue, Boston, Massachusetts 02115. fax: (617) 730-0498.
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Maldonado-Contreras A, Birtley JR, Boll E, Zhao Y, Mumy KL, Toscano J, Ayehunie S, Reinecker HC, Stern LJ, McCormick BA. Shigella depends on SepA to destabilize the intestinal epithelial integrity via cofilin activation. Gut Microbes 2017; 8:544-560. [PMID: 28598765 PMCID: PMC5730386 DOI: 10.1080/19490976.2017.1339006] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Shigella is unique among enteric pathogens, as it invades colonic epithelia through the basolateral pole. Therefore, it has evolved the ability to breach the intestinal epithelial barrier to deploy an arsenal of effector proteins, which permits bacterial invasion and leads to a severe inflammatory response. However, the mechanisms used by Shigella to regulate epithelial barrier permeability remain unknown. To address this question, we used both an intestinal polarized model and a human ex-vivo model to further characterize the early events of host-bacteria interactions. Our results showed that secreted Serine Protease A (SepA), which belongs to the serine protease autotransporter of Enterobacteriaceae family, is responsible for critically disrupting the intestinal epithelial barrier. Such disruption facilitates bacterial transit to the basolateral pole of the epithelium, ultimately fostering the hallmarks of the disease pathology. SepA was found to cause a decrease in active LIM Kinase 1 (LIMK1) levels, a negative inhibitor of actin-remodeling proteins, namely cofilin. Correspondingly, we observed increased activation of cofilin, a major actin-polymerization factor known to control opening of tight junctions at the epithelial barrier. Furthermore, we resolved the crystal structure of SepA to elucidate its role on actin-dynamics and barrier disruption. The serine protease activity of SepA was found to be required for the regulatory effects on LIMK1 and cofilin, resulting in the disruption of the epithelial barrier during infection. Altogether, we demonstrate that SepA is indispensable for barrier disruption, ultimately facilitating Shigella transit to the basolateral pole where it effectively invades the epithelium.
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Affiliation(s)
- Ana Maldonado-Contreras
- Department of Microbiology and Physiological Systems, University of Massachusetts, Medical School, Worcester, MA, USA,CONTACT Beth A. McCormick ; Ana Maldonado-Contreras 55 Lake Ave N, Worcester, MA, 01655
| | - James R. Birtley
- Department of Pathology, University of Massachusetts, Medical School, Worcester, MA, USA
| | - Erik Boll
- Statens Serum Institut, Copenhagen, Denmark
| | - Yun Zhao
- Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Karen L. Mumy
- Naval Medical Research Unit Dayton, Wright-Patterson Air Force Base, Dayton, OH, USA
| | - Juan Toscano
- Department of Microbiology and Physiological Systems, University of Massachusetts, Medical School, Worcester, MA, USA
| | | | - Hans-Christian Reinecker
- Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Lawrence J. Stern
- Department of Pathology, University of Massachusetts, Medical School, Worcester, MA, USA
| | - Beth A. McCormick
- Department of Microbiology and Physiological Systems, University of Massachusetts, Medical School, Worcester, MA, USA,CONTACT Beth A. McCormick ; Ana Maldonado-Contreras 55 Lake Ave N, Worcester, MA, 01655
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10
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DeBoer MD, Vijayakumar V, Gong M, Fowlkes JL, Smith RM, Ruiz-Perez F, Nataro JP. Mice with infectious colitis exhibit linear growth failure and subsequent catch-up growth related to systemic inflammation and IGF-1. Nutr Res 2017; 39:34-42. [PMID: 28385287 DOI: 10.1016/j.nutres.2017.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 01/06/2017] [Accepted: 02/03/2017] [Indexed: 02/04/2023]
Abstract
In developing communities, intestinal infection is associated with poor weight gain and linear-growth failure. Prior translational animal models have focused on weight gain investigations into key contributors to linear growth failure have been lacking. We hypothesized that murine intestinal infection with Citrobacter rodentium would induce linear-growth failure associated with systemic inflammation and suppressed serum levels of insulin-like growth factor-1 (IGF-1). We evaluated 4 groups of mice infected or sham-infected on day-of-life 28: uninfected-controls, wild-type C rodentium-infected, partially-attenuated C rodentium-infected (with deletion of 3 serine protease genes involved in colonization), and pair-fed (given the amount of daily food consumed by the wild-type C rodentium group). Relative to the uninfected group, mice infected with wild-type C rodentium exhibited temporal associations of lower food intake, weight loss, linear-growth failure, higher IL-6 and TNF-α and lower IGF-1. However, relative to the pair-fed group, the C rodentium-infected group only differed significantly by linear growth and systemic inflammatory cytokines. Between post-infection days 15-20, the infected group exhibited resolution of systemic inflammation. Between days 16-20, both wild-type C rodentium and pair-fed groups exhibited rapid linear-growth velocities exceeding the uninfected and mutant C rodentium groups; during this time levels of IGF-1 increased to match the uninfected group. We submit this as a model providing important opportunities to study mechanisms of catch-up growth related to intestinal inflammation. We conclude that in addition to known effects of weight loss, infection with C rodentium induces linear-growth failure potentially related to systemic inflammation and low levels of IGF-1, with catch-up of linear growth following resolution of inflammation.
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Affiliation(s)
- Mark D DeBoer
- Division of Pediatric Endocrinology, University of Virginia, Charlottesville, VA; Department of Pediatrics, University of Virginia, Charlottesville, VA.
| | - Vidhya Vijayakumar
- Department of Pediatrics, University of Virginia, Charlottesville, VA; Division of Pediatric Infectious Disease, University of Virginia, Charlottesville, VA
| | - Meiqing Gong
- Department of Pediatrics, University of Virginia, Charlottesville, VA; Division of Pediatric Infectious Disease, University of Virginia, Charlottesville, VA
| | - John L Fowlkes
- Barnstable Brown Diabetes Center and Division of Pediatric Endocrinology, Department of Pediatrics, University of Kentucky, Lexington, KY
| | - Rachel M Smith
- Department of Pediatrics, University of Virginia, Charlottesville, VA; Division of Pediatric Infectious Disease, University of Virginia, Charlottesville, VA
| | - Fernando Ruiz-Perez
- Department of Pediatrics, University of Virginia, Charlottesville, VA; Division of Pediatric Infectious Disease, University of Virginia, Charlottesville, VA
| | - James P Nataro
- Department of Pediatrics, University of Virginia, Charlottesville, VA; Division of Pediatric Infectious Disease, University of Virginia, Charlottesville, VA
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Gaytán MO, Martínez-Santos VI, Soto E, González-Pedrajo B. Type Three Secretion System in Attaching and Effacing Pathogens. Front Cell Infect Microbiol 2016; 6:129. [PMID: 27818950 PMCID: PMC5073101 DOI: 10.3389/fcimb.2016.00129] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/27/2016] [Indexed: 02/06/2023] Open
Abstract
Enteropathogenic Escherichia coli and enterohemorrhagic E. coli are diarrheagenic bacterial human pathogens that cause severe gastroenteritis. These enteric pathotypes, together with the mouse pathogen Citrobacter rodentium, belong to the family of attaching and effacing pathogens that form a distinctive histological lesion in the intestinal epithelium. The virulence of these bacteria depends on a type III secretion system (T3SS), which mediates the translocation of effector proteins from the bacterial cytosol into the infected cells. The core architecture of the T3SS consists of a multi-ring basal body embedded in the bacterial membranes, a periplasmic inner rod, a transmembrane export apparatus in the inner membrane, and cytosolic components including an ATPase complex and the C-ring. In addition, two distinct hollow appendages are assembled on the extracellular face of the basal body creating a channel for protein secretion: an approximately 23 nm needle, and a filament that extends up to 600 nm. This filamentous structure allows these pathogens to get through the host cells mucus barrier. Upon contact with the target cell, a translocation pore is assembled in the host membrane through which the effector proteins are injected. Assembly of the T3SS is strictly regulated to ensure proper timing of substrate secretion. The different type III substrates coexist in the bacterial cytoplasm, and their hierarchical secretion is determined by specialized chaperones in coordination with two molecular switches and the so-called sorting platform. In this review, we present recent advances in the understanding of the T3SS in attaching and effacing pathogens.
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Affiliation(s)
- Meztlli O Gaytán
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Verónica I Martínez-Santos
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Eduardo Soto
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México Ciudad de México, Mexico
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The secreted autotransporter toxin (Sat) does not act as a virulence factor in the probiotic Escherichia coli strain Nissle 1917. BMC Microbiol 2015; 15:250. [PMID: 26518156 PMCID: PMC4628265 DOI: 10.1186/s12866-015-0591-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 10/25/2015] [Indexed: 12/11/2022] Open
Abstract
Background Escherichia coli Nissle 1917 (EcN) is a probiotic used in the treatment of intestinal diseases. Although it is considered safe, EcN is closely related to the uropathogenic E. coli strain CFT073 and contains many of its predicted virulence elements. Thus, it is relevant to assess whether virulence-associated genes are functional in EcN. One of these genes encodes the secreted autotransporter toxin (Sat), a member of the serine protease autotransporters of Enterobacteriaceae (SPATEs) that are secreted following the type V autotransporter pathway. Sat is highly prevalent in certain E. coli pathogenic groups responsible for urinary and intestinal infections. In these pathogens Sat promotes cytotoxic effects in several lines of undifferentiated epithelial cells, but not in differentiated Caco-2 cells. Results Here we provide evidence that sat is expressed by EcN during the colonization of mouse intestine. The EcN protein is secreted as an active serine protease, with its 107 kDa-passenger domain released into the medium as a soluble protein. Expression of recombinant EcN Sat protein in strain HB101 increases paracellular permeability to mannitol in polarized Caco-2 monolayers. This effect, also reported for the Sat protein of diffusely adherent E. coli, is not observed when this protein is expressed in the EcN background. In addition, we show that EcN supernatants confer protection against Sat-mediated effects on paracellular permeability, thus indicating that other secreted EcN factors are able to prevent barrier disruption caused by pathogen-related factors. Sat is not required for intestinal colonization, but the EcNsat::cat mutant outcompetes wild-type EcN in the streptomycin-treated mouse model. Analysis of the presence of sat in 29 strains of the ECOR collection isolated from stools of healthy humans shows 34.8 % positives, with high prevalence of strains of the phylogenetic groups D and B2, related with extra-intestinal infections. Conclusions Sat does not act as a virulence factor in EcN. The role of Sat in intestinal pathogenesis relies on other genetic determinants responsible for the bacterial pathotype. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0591-5) contains supplementary material, which is available to authorized users.
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The Serine Protease Autotransporter Pic Modulates Citrobacter rodentium Pathogenesis and Its Innate Recognition by the Host. Infect Immun 2015; 83:2636-50. [PMID: 25895966 DOI: 10.1128/iai.00025-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Bacterial pathogens produce a number of autotransporters that possess diverse functions. These include the family of serine protease autotransporters of Enterobacteriaceae (SPATEs) produced by enteric pathogens such as Shigella flexneri and enteroaggregative Escherichia coli. Of these SPATEs, one termed "protein involved in colonization," or Pic, has been shown to possess mucinase activity in vitro, but to date, its role in in vivo enteric pathogenesis is unknown. Testing a pic null (ΔpicC) mutant in Citrobacter rodentium, a natural mouse pathogen, found that the C. rodentium ΔpicC strain was impaired in its ability to degrade mucin in vitro compared to the wild type. Upon infection of mice, the ΔpicC mutant exhibited a hypervirulent phenotype with dramatically heavier pathogen burdens found in intestinal crypts. ΔpicC mutant-infected mice suffered greater barrier disruption and more severe colitis and weight loss, necessitating their euthanization between 10 and 14 days postinfection. Notably, the virulence of the ΔpicC mutant was normalized when the picC gene was restored; however, a PicC point mutant causing loss of mucinase activity did not replicate the ΔpicC phenotype. Exploring other aspects of PicC function, the ΔpicC mutant was found to aggregate to higher levels in vivo than wild-type C. rodentium. Moreover, unlike the wild type, the C. rodentium ΔpicC mutant had a red, dry, and rough (RDAR) morphology in vitro and showed increased activation of the innate receptor Toll-like receptor 2 (TLR2). Interestingly, the C. rodentium ΔpicC mutant caused a degree of pathology similar to that of wild-type C. rodentium when infecting TLR2-deficient mice, showing that despite its mucinase activity, PicC's major role in vivo may be to limit C. rodentium's stimulation of the host's innate immune system.
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Guignot J, Segura A, Tran Van Nhieu G. The Serine Protease EspC from Enteropathogenic Escherichia coli Regulates Pore Formation and Cytotoxicity Mediated by the Type III Secretion System. PLoS Pathog 2015; 11:e1005013. [PMID: 26132339 PMCID: PMC4488501 DOI: 10.1371/journal.ppat.1005013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 06/08/2015] [Indexed: 12/17/2022] Open
Abstract
Type III secretion systems (T3SSs) are specialized macromolecular machines critical for bacterial virulence, and allowing the injection of bacterial effectors into host cells. The T3SS-dependent injection process requires the prior insertion of a protein complex, the translocon, into host cell membranes consisting of two-T3SS hydrophobic proteins, associated with pore-forming activity. In all described T3SS to date, a hydrophilic protein connects one hydrophobic component to the T3SS needle, presumably insuring the continuum between the hollow needle and the translocon. In the case of Enteropathogenic Escherichia coli (EPEC), the hydrophilic component EspA polymerizes into a filament connecting the T3SS needle to the translocon composed of the EspB and EspD hydrophobic proteins. Here, we identify EspA and EspD as targets of EspC, a serine protease autotransporter of Enterobacteriaceae (SPATE). We found that in vitro, EspC preferentially targets EspA associated with EspD, but was less efficient at proteolyzing EspA alone. Consistently, we found that EspC did not regulate EspA filaments at the surface of primed bacteria that was devoid of EspD, but controlled the levels of EspD and EspA secreted in vitro or upon cell contact. While still proficient for T3SS-mediated injection of bacterial effectors and cytoskeletal reorganization, an espC mutant showed increased levels of cell-associated EspA and EspD, as well as increased pore formation activity associated with cytotoxicity. EspP from enterohaemorrhagic E. coli (EHEC) also targeted translocator components and its activity was interchangeable with that of EspC, suggesting a common and important function of these SPATEs. These findings reveal a novel regulatory mechanism of T3SS-mediated pore formation and cytotoxicity control during EPEC/EHEC infection.
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Affiliation(s)
- Julie Guignot
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, Paris, France
- Institut National de la Santé et de la Recherche Médicale U1050, Paris, France
- Centre National de la Recherche Scientifique UMR7241, Paris, France
- MEMOLIFE Laboratory of Excellence and Paris Science Lettre, Paris, France
| | - Audrey Segura
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, Paris, France
- Institut National de la Santé et de la Recherche Médicale U1050, Paris, France
- Centre National de la Recherche Scientifique UMR7241, Paris, France
- MEMOLIFE Laboratory of Excellence and Paris Science Lettre, Paris, France
| | - Guy Tran Van Nhieu
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, Paris, France
- Institut National de la Santé et de la Recherche Médicale U1050, Paris, France
- Centre National de la Recherche Scientifique UMR7241, Paris, France
- MEMOLIFE Laboratory of Excellence and Paris Science Lettre, Paris, France
- * E-mail:
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