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Nandi I, Aroeti B. Mitogen-Activated Protein Kinases (MAPKs) and Enteric Bacterial Pathogens: A Complex Interplay. Int J Mol Sci 2023; 24:11905. [PMID: 37569283 PMCID: PMC10419152 DOI: 10.3390/ijms241511905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 07/19/2023] [Accepted: 07/19/2023] [Indexed: 08/13/2023] Open
Abstract
Diverse extracellular and intracellular cues activate mammalian mitogen-activated protein kinases (MAPKs). Canonically, the activation starts at cell surface receptors and continues via intracellular MAPK components, acting in the host cell nucleus as activators of transcriptional programs to regulate various cellular activities, including proinflammatory responses against bacterial pathogens. For instance, binding host pattern recognition receptors (PRRs) on the surface of intestinal epithelial cells to bacterial pathogen external components trigger the MAPK/NF-κB signaling cascade, eliciting cytokine production. This results in an innate immune response that can eliminate the bacterial pathogen. However, enteric bacterial pathogens evolved sophisticated mechanisms that interfere with such a response by delivering virulent proteins, termed effectors, and toxins into the host cells. These proteins act in numerous ways to inactivate or activate critical components of the MAPK signaling cascades and innate immunity. The consequence of such activities could lead to successful bacterial colonization, dissemination, and pathogenicity. This article will review enteric bacterial pathogens' strategies to modulate MAPKs and host responses. It will also discuss findings attempting to develop anti-microbial treatments by targeting MAPKs.
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Affiliation(s)
| | - Benjamin Aroeti
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190410, Israel;
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2
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Popov G, Fiebig-Comyn A, Syriste L, Little DJ, Skarina T, Stogios PJ, Birstonas S, Coombes BK, Savchenko A. Distinct Molecular Features of NleG Type 3 Secreted Effectors Allow for Different Roles during Citrobacter rodentium Infection in Mice. Infect Immun 2023; 91:e0050522. [PMID: 36511702 PMCID: PMC9872709 DOI: 10.1128/iai.00505-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 11/19/2022] [Indexed: 12/15/2022] Open
Abstract
The NleGs are the largest family of type 3 secreted effectors in attaching and effacing (A/E) pathogens, such as enterohemorrhagic Escherichia coli (EHEC), enteropathogenic E. coli, and Citrobacter rodentium. NleG effectors contain a conserved C-terminal U-box domain acting as a ubiquitin protein ligase and target host proteins via a variable N-terminal portion. The specific roles of these effectors during infection remain uncertain. Here, we demonstrate that the three NleG effectors-NleG1Cr, NleG7Cr, and NleG8Cr-encoded by C. rodentium DBS100 play distinct roles during infection in mice. Using individual nleGCr knockout strains, we show that NleG7Cr contributes to bacterial survival during enteric infection while NleG1Cr promotes the expression of diarrheal symptoms and NleG8Cr contributes to accelerated lethality in susceptible mice. Furthermore, the NleG8Cr effector contains a C-terminal PDZ domain binding motif that enables interaction with the host protein GOPC. Both the PDZ domain binding motif and the ability to engage with host ubiquitination machinery via the intact U-box domain proved to be necessary for NleG8Cr function, contributing to the observed phenotype during infection. We also establish that the PTZ binding motif in the EHEC NleG8 (NleG8Ec) effector, which shares 60% identity with NleG8Cr, is engaged in interactions with human GOPC. The crystal structure of the NleG8Ec C-terminal peptide in complex with the GOPC PDZ domain, determined to 1.85 Å, revealed a conserved interaction mode similar to that observed between GOPC and eukaryotic PDZ domain binding motifs. Despite these common features, nleG8Ec does not complement the ΔnleG8Cr phenotype during infection, revealing functional diversification between these NleG effectors.
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Affiliation(s)
- Georgy Popov
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Aline Fiebig-Comyn
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Lukas Syriste
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Dustin J. Little
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Tatiana Skarina
- Department of Chemical Engineering and Applied Chemistry, Toronto University, Toronto, Ontario, Canada
| | - Peter J. Stogios
- Department of Chemical Engineering and Applied Chemistry, Toronto University, Toronto, Ontario, Canada
| | - Sarah Birstonas
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Brian K. Coombes
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Alexei Savchenko
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Chemical Engineering and Applied Chemistry, Toronto University, Toronto, Ontario, Canada
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3
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Feiss M, Young R, Ramsey J, Adhya S, Georgopoulos C, Hendrix RW, Hatfull GF, Gilcrease EB, Casjens SR. Hybrid Vigor: Importance of Hybrid λ Phages in Early Insights in Molecular Biology. Microbiol Mol Biol Rev 2022; 86:e0012421. [PMID: 36165780 PMCID: PMC9799177 DOI: 10.1128/mmbr.00124-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Laboratory-generated hybrids between phage λ and related phages played a seminal role in establishment of the λ model system, which, in turn, served to develop many of the foundational concepts of molecular biology, including gene structure and control. Important λ hybrids with phages 21 and 434 were the earliest of such phages. To understand the biology of these hybrids in full detail, we determined the complete genome sequences of phages 21 and 434. Although both genomes are canonical members of the λ-like phage family, they both carry unsuspected bacterial virulence gene types not previously described in this group of phages. In addition, we determined the sequences of the hybrid phages λ imm21, λ imm434, and λ h434 imm21. These sequences show that the replacements of λ DNA by nonhomologous segments of 21 or 434 DNA occurred through homologous recombination in adjacent sequences that are nearly identical in the parental phages. These five genome sequences correct a number of errors in published sequence fragments of the 21 and 434 genomes, and they point out nine nucleotide differences from Sanger's original λ sequence that are likely present in most extant λ strains in laboratory use today. We discuss the historical importance of these hybrid phages in the development of fundamental tenets of molecular biology and in some of the earliest gene cloning vectors. The 434 and 21 genomes reinforce the conclusion that the genomes of essentially all natural λ-like phages are mosaics of sequence modules from a pool of exchangeable segments.
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Affiliation(s)
- Michael Feiss
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Ryland Young
- Center for Phage Technology, Texas A&M AgriLife Research, College Station, Texas, USA
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Jolene Ramsey
- Center for Phage Technology, Texas A&M AgriLife Research, College Station, Texas, USA
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Sankar Adhya
- Laboratory of Molecular Biology, Center for Cancer Research, The National Cancer Institute, Bethesda, Maryland, USA
| | - Costa Georgopoulos
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Roger W. Hendrix
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Pittsburgh Bacteriophage Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Graham F. Hatfull
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Pittsburgh Bacteriophage Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Eddie B. Gilcrease
- Department of Civil and Environmental Engineering, University of Utah, Salt Lake City, Utah, USA
| | - Sherwood R. Casjens
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, USA
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
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4
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Ciaston I, Dobosz E, Potempa J, Koziel J. The subversion of toll-like receptor signaling by bacterial and viral proteases during the development of infectious diseases. Mol Aspects Med 2022; 88:101143. [PMID: 36152458 PMCID: PMC9924004 DOI: 10.1016/j.mam.2022.101143] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/29/2022] [Accepted: 09/09/2022] [Indexed: 02/05/2023]
Abstract
Toll-like receptors (TLRs) are pattern recognition receptors (PRRs) that respond to pathogen-associated molecular patterns (PAMPs). The recognition of specific microbial ligands by TLRs triggers an innate immune response and also promotes adaptive immunity, which is necessary for the efficient elimination of invading pathogens. Successful pathogens have therefore evolved strategies to subvert and/or manipulate TLR signaling. Both the impairment and uncontrolled activation of TLR signaling can harm the host, causing tissue destruction and allowing pathogens to proliferate, thus favoring disease progression. In this context, microbial proteases are key virulence factors that modify components of the TLR signaling pathway. In this review, we discuss the role of bacterial and viral proteases in the manipulation of TLR signaling, highlighting the importance of these enzymes during the development of infectious diseases.
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Affiliation(s)
- Izabela Ciaston
- Department of Microbiology Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Ewelina Dobosz
- Department of Microbiology Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Jan Potempa
- Department of Microbiology Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland; Department of Oral Health and Systemic Disease, University of Louisville School of Dentistry, University of Louisville, Louisville, KY, USA.
| | - Joanna Koziel
- Department of Microbiology Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
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Viana F, Peringathara SS, Rizvi A, Schroeder GN. Host manipulation by bacterial type III and type IV secretion system effector proteases. Cell Microbiol 2021; 23:e13384. [PMID: 34392594 DOI: 10.1111/cmi.13384] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/28/2021] [Accepted: 07/30/2021] [Indexed: 01/08/2023]
Abstract
Proteases are powerful enzymes, which cleave peptide bonds, leading most of the time to irreversible fragmentation or degradation of their substrates. Therefore they control many critical cell fate decisions in eukaryotes. Bacterial pathogens exploit this power and deliver protease effectors through specialised secretion systems into host cells. Research over the past years revealed that the functions of protease effectors during infection are diverse, reflecting the lifestyles and adaptations to specific hosts; however, only a small number of peptidase families seem to have given rise to most of these protease virulence factors by the evolution of different substrate-binding specificities, intracellular activation and subcellular targeting mechanisms. Here, we review our current knowledge about the enzymology and function of protease effectors, which Gram-negative bacterial pathogens translocate via type III and IV secretion systems to irreversibly manipulate host processes. We highlight emerging concepts such as signalling by protease cleavage products and effector-triggered immunity, which host cells employ to detect and defend themselves against a protease attack. TAKE AWAY: Proteases irreversibly cleave proteins to control critical cell fate decisions. Gram-negative bacteria use type III and IV secretion systems to inject effectors. Protease effectors are integral weapons for the manipulation of host processes. Effectors evolved from few peptidase families to target diverse substrates. Effector-triggered immunity upon proteolytic attack emerges as host defence.
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Affiliation(s)
- Flávia Viana
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Shruthi Sachidanandan Peringathara
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Arshad Rizvi
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Gunnar N Schroeder
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
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Hasan MK, El Qaidi S, Hardwidge PR. The T3SS Effector Protease NleC Is Active within Citrobacter rodentium. Pathogens 2021; 10:pathogens10050589. [PMID: 34065796 PMCID: PMC8151275 DOI: 10.3390/pathogens10050589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/06/2021] [Accepted: 05/10/2021] [Indexed: 11/18/2022] Open
Abstract
Whether type III secretion system (T3SS) effector proteins encoded by Gram-negative bacterial pathogens have intra-bacterial activities is an important and emerging area of investigation. Gram-negative bacteria interact with their mammalian hosts by using secretion systems to inject virulence proteins directly into infected host cells. Many of these injected protein effectors are enzymes that modify the structure and inhibit the function of mammalian proteins. The underlying dogma is that T3SS effectors are inactive until they are injected into host cells, where they then fold into their active conformations. We previously observed that the T3SS effectors NleB and SseK1 glycosylate Citrobacter rodentium and Salmonella enterica proteins, respectively, leading to enhanced resistance to environmental stress. Here, we sought to extend these studies to determine whether the T3SS effector protease NleC is also active within C. rodentium. To do this, we expressed the best-characterized mammalian substrate of NleC, the NF-κB p65 subunit in C. rodentium and monitored its proteolytic cleavage as a function of NleC activity. Intra-bacterial p65 cleavage was strictly dependent upon NleC. A p65 mutant lacking the known CE cleavage motif was resistant to NleC. Thus, we conclude that, in addition to NleB, NleC is also enzymatically active within C. rodentium.
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Abstract
Diarrheal disease is still a major public health concern, as it is still considered an important cause of death in children under five years of age. A few decades ago, the detection of enteropathogenic E. coli was made by detecting the O, H, and K antigens, mostly by agglutination. The recent protocols recommend the molecular methods for diagnosing EPEC, as they can distinguish between typical and atypical EPEC by identifying the presence/absence of specific virulence factors. EPEC are defined as diarrheagenic strains of E. coli that can produce attaching and effacing lesions on the intestinal epithelium while being incapable of producing Shiga toxins and heat-labile or heat-stable enterotoxins. The ability of these strains to produce attaching and effacing lesions enable them to cause localized lesions by attaching tightly to the surface of the intestinal epithelial cells, disrupting the surfaces of the cells, thus leading to the effacement of the microvilli. EPEC are classified on typical and atypical isolates, based on the presence or absence of E. coli adherence factor plasmids. All the EPEC strains are eae positive; typical EPEC strains are eae+, bfpA+, while atypical strains are eae+, bfpA−. No vaccines are currently available to prevent EPEC infections.
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Riebisch AK, Mühlen S. Attaching and effacing pathogens: the effector ABC of immune subversion. Future Microbiol 2020; 15:945-958. [PMID: 32716209 DOI: 10.2217/fmb-2019-0274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The innate immune response resembles an essential barrier to bacterial infection. Many bacterial pathogens have, therefore, evolved mechanisms to evade from or subvert the host immune response in order to colonize, survive and multiply. The attaching and effacing pathogens enteropathogenic Escherichia coli, enterohaemorrhagic E. coli, Escherichia albertii and Citrobacter rodentium are Gram-negative extracellular gastrointestinal pathogens. They use a type III secretion system to inject effector proteins into the host cell to manipulate a variety of cellular processes. Over the last decade, considerable progress was made in identifying and characterizing the effector proteins of attaching and effacing pathogens that are involved in the inhibition of innate immune signaling pathways, in determining their host cell targets and elucidating the mechanisms they employ. Their functions will be reviewed here.
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Affiliation(s)
- Anna Katharina Riebisch
- Systems-Oriented Immunology & Inflammation Research, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.,Institute for Molecular & Clinical Immunology, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany.,Department of Molecular Immunology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Sabrina Mühlen
- Institute for Infectiology, University of Münster, 48149 Münster, Germany.,German Center for Infection Research (DZIF), Associated Site University of Münster, 48149 Münster, Germany
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9
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Pan X, Luo J, Li S. Bacteria-Catalyzed Arginine Glycosylation in Pathogens and Host. Front Cell Infect Microbiol 2020; 10:185. [PMID: 32411621 PMCID: PMC7199390 DOI: 10.3389/fcimb.2020.00185] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 04/07/2020] [Indexed: 01/25/2023] Open
Abstract
In recent years, protein glycosylation in pathogenic bacteria has attracted more and more attention, and accumulating evidence indicated that this type of posttranslational modification is involved in many physiological processes. The NleB from several enteropathogenic bacteria species as well as SseK from Salmonella enterica are type III secretion system effectors, which have an atypical N-acetylglucosamine (N-GlcNAc) transferase activity that specifically modified a conserved arginine in TRADD, FADD, and RIPK1. NleB/SseKs GlcNAcylation of death domain proteins abrogates homotypic and heterotypic death receptors/adaptors interactions, thereby blocking an important antimicrobial host response. Interestingly, NleB/SseKs could also GlcNAcylate themselves, and self-GlcNAcylation of NleB, SseK1, and SseK3 are crucial for their biological activity during infection. In addition, EarP (EF-P specific arginine rhamnosyl transferase for Posttranslational activation) catalyzes arginine rhamnosylation of translation elongation factor P (EF-P). Importantly, this kind of N-linked protein glycosylation is not only important for EF-P dependent rescue of polyproline stalled ribosomes but also for pathogenicity in Pseudomonas aeruginosa and other clinically relevant bacteria. Glycosylation of arginine is unique because the guanidine group of arginine has a high acid dissociation constant value and representing an extremely poor nucleophile. Recently, the crystal structures of NleB, SseKs, EarP, arginine GlcNAcylated death domain-containing proteins, NleB/FADD-DD, and EarP/EF-P/dTDP-β-L-rhamnose were solved by our group and other groups, revealing the unique catalytic mechanisms. In this review, we provide detailed information about the currently known arginine glycosyltransferases and their potential catalytic mechanisms.
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Affiliation(s)
- Xing Pan
- Institute of Infection and Immunity, Taihe Hospital, Hubei University of Medicine, Shiyan, China.,College of Biomedicine and Health, Huazhong Agricultural University, Wuhan, China.,College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jie Luo
- Institute of Infection and Immunity, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Shan Li
- Institute of Infection and Immunity, Taihe Hospital, Hubei University of Medicine, Shiyan, China.,College of Biomedicine and Health, Huazhong Agricultural University, Wuhan, China.,College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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10
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Molecular Mechanisms That Define Redox Balance Function in Pathogen-Host Interactions-Is There a Role for Dietary Bioactive Polyphenols? Int J Mol Sci 2019; 20:ijms20246222. [PMID: 31835548 PMCID: PMC6940965 DOI: 10.3390/ijms20246222] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/02/2019] [Accepted: 12/03/2019] [Indexed: 01/01/2023] Open
Abstract
To ensure a functional immune system, the mammalian host must detect and respond to the presence of pathogenic bacteria during infection. This is accomplished in part by generating reactive oxygen species (ROS) that target invading bacteria; a process that is facilitated by NADPH oxidase upregulation. Thus, bacterial pathogens must overcome the oxidative burst produced by the host innate immune cells in order to survive and proliferate. In this way, pathogenic bacteria develop virulence, which is related to the affinity to secrete effector proteins against host ROS in order to facilitate microbial survival in the host cell. These effectors scavenge the host generated ROS directly, or alternatively, manipulate host cell signaling mechanisms designed to benefit pathogen survival. The redox-balance of the host is important for the regulation of cell signaling activities that include mitogen-activated protein kinase (MAPK), p21-activated kinase (PAK), phosphatidylinositol 3-kinase (PI3K)/Akt, and nuclear factor κB (NF-κB) pathways. An understanding of the function of pathogenic effectors to divert host cell signaling is important to ascertain the mechanisms underlying pathogen virulence and the eventual host–pathogen relationship. Herein, we examine the effectors produced by the microbial secretion system, placing emphasis on how they target molecular signaling mechanisms involved in a host immune response. Moreover, we discuss the potential impact of bioactive polyphenols in modulating these molecular interactions that will ultimately influence pathogen virulence.
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Bioinformatic discovery of a toxin family in Chryseobacterium piperi with sequence similarity to botulinum neurotoxins. Sci Rep 2019; 9:1634. [PMID: 30733520 PMCID: PMC6367388 DOI: 10.1038/s41598-018-37647-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 12/05/2018] [Indexed: 11/12/2022] Open
Abstract
Clostridial neurotoxins (CNTs), which include botulinum neurotoxins (BoNTs) and tetanus neurotoxin (TeNT), are the most potent toxins known to science and are the causative agents of botulism and tetanus, respectively. The evolutionary origins of CNTs and their relationships to other proteins remains an intriguing question. Here we present a large-scale bioinformatic screen for putative toxin genes in all currently available genomes. We detect a total of 311 protein sequences displaying at least partial homology to BoNTs, including 161 predicted toxin sequences that have never been characterized. We focus on a novel toxin family from Chryseobacterium piperi with homology to BoNTs. We resequenced the genome of C. piperi to confirm and further analyze the genomic context of these toxins, and also examined their potential toxicity by expression of the protease domain of one C. piperi toxin in human cells. Our analysis suggests that these C. piperi sequences encode a novel family of metalloprotease toxins that are distantly related to BoNTs with similar domain architecture. These toxins target a yet unknown class of substrates, potentially reflecting divergence in substrate specificity between the metalloprotease domains of these toxins and the related metalloprotease domain of clostridial neurotoxins.
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12
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Mansfield MJ, Doxey AC. Genomic insights into the evolution and ecology of botulinum neurotoxins. Pathog Dis 2018; 76:4978416. [PMID: 29684130 DOI: 10.1093/femspd/fty040] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 04/17/2018] [Indexed: 11/14/2022] Open
Affiliation(s)
- Michael J Mansfield
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
| | - Andrew C Doxey
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
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13
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El Qaidi S, Wu M, Zhu C, Hardwidge PR. Salmonella, E. coli, and Citrobacter Type III Secretion System Effector Proteins that Alter Host Innate Immunity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1111:205-218. [PMID: 30411307 DOI: 10.1007/5584_2018_289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Bacteria deliver virulence proteins termed 'effectors' to counteract host innate immunity. Protein-protein interactions within the host cell ultimately subvert the generation of an inflammatory response to the infecting pathogen. Here we briefly describe a subset of T3SS effectors produced by enterohemorrhagic Escherichia coli (EHEC), enteropathogenic E. coli (EPEC), Citrobacter rodentium, and Salmonella enterica that inhibit innate immune pathways. These effectors are interesting for structural and mechanistic reasons, as well as for their potential utility in being engineered to treat human autoimmune disorders associated with perturbations in NF-κB signaling.
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Affiliation(s)
- Samir El Qaidi
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Miaomiao Wu
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Congrui Zhu
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Philip R Hardwidge
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA.
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