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Lepesheva A, Grobarcikova M, Osickova A, Jurnecka D, Knoblochova S, Cizkova M, Osicka R, Sebo P, Masin J. Modification of the RTX domain cap by acyl chains of adapted length rules the formation of functional hemolysin pores. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184311. [PMID: 38570122 DOI: 10.1016/j.bbamem.2024.184311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/14/2024] [Accepted: 03/25/2024] [Indexed: 04/05/2024]
Abstract
The acylated pore-forming Repeats in ToXin (RTX) cytolysins α-hemolysin (HlyA) and adenylate cyclase toxin (CyaA) preferentially bind to β2 integrins of myeloid leukocytes but can also promiscuously bind and permeabilize cells lacking the β2 integrins. We constructed a HlyA1-563/CyaA860-1706 chimera that was acylated either by the toxin-activating acyltransferase CyaC, using sixteen carbon-long (C16) acyls, or by the HlyC acyltransferase using fourteen carbon-long (C14) acyls. Cytolysin assays with the C16- or C14-acylated HlyA/CyaA chimeric toxin revealed that the RTX domain of CyaA can functionally replace the RTX domain of HlyA only if it is modified by C16-acyls on the Lys983 residue of CyaA. The C16-monoacylated HlyA/CyaA chimera was as pore-forming and cytolytic as native HlyA, whereas the C14-acylated chimera exhibited very low pore-forming activity. Hence, the capacity of the RTX domain of CyaA to support the insertion of the N-terminal pore-forming domain into the target cell membrane, and promote formation of toxin pores, strictly depends on the modification of the Lys983 residue by an acyl chain of adapted length.
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Affiliation(s)
- Anna Lepesheva
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Michaela Grobarcikova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Sarka Knoblochova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Monika Cizkova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
| | - Jiri Masin
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
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2
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Whelan S, Lucey B, Finn K. Uropathogenic Escherichia coli (UPEC)-Associated Urinary Tract Infections: The Molecular Basis for Challenges to Effective Treatment. Microorganisms 2023; 11:2169. [PMID: 37764013 PMCID: PMC10537683 DOI: 10.3390/microorganisms11092169] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/23/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023] Open
Abstract
Urinary tract infections (UTIs) are among the most common bacterial infections, especially among women and older adults, leading to a significant global healthcare cost burden. Uropathogenic Escherichia coli (UPEC) are the most common cause and accounts for the majority of community-acquired UTIs. Infection by UPEC can cause discomfort, polyuria, and fever. More serious clinical consequences can result in urosepsis, kidney damage, and death. UPEC is a highly adaptive pathogen which presents significant treatment challenges rooted in a complex interplay of molecular factors that allow UPEC to evade host defences, persist within the urinary tract, and resist antibiotic therapy. This review discusses these factors, which include the key genes responsible for adhesion, toxin production, and iron acquisition. Additionally, it addresses antibiotic resistance mechanisms, including chromosomal gene mutations, antibiotic deactivating enzymes, drug efflux, and the role of mobile genetic elements in their dissemination. Furthermore, we provide a forward-looking analysis of emerging alternative therapies, such as phage therapy, nano-formulations, and interventions based on nanomaterials, as well as vaccines and strategies for immunomodulation. This review underscores the continued need for research into the molecular basis of pathogenesis and antimicrobial resistance in the treatment of UPEC, as well as the need for clinically guided treatment of UTIs, particularly in light of the rapid spread of multidrug resistance.
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Affiliation(s)
- Shane Whelan
- Department of Biological Sciences, Munster Technological University, Bishopstown, T12 P928 Cork, Ireland;
| | - Brigid Lucey
- Department of Biological Sciences, Munster Technological University, Bishopstown, T12 P928 Cork, Ireland;
| | - Karen Finn
- Department of Analytical, Biopharmaceutical and Medical Sciences, Atlantic Technological University Galway City, Dublin Road, H91 T8NW Galway, Ireland
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3
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Cané L, Guzmán F, Balatti G, Daza Millone MA, Pucci Molineris M, Maté S, Martini MF, Herlax V. Biophysical Analysis to Assess the Interaction of CRAC and CARC Motif Peptides of Alpha Hemolysin of Escherichia coli with Membranes. Biochemistry 2023. [PMID: 37224476 DOI: 10.1021/acs.biochem.3c00164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Alpha hemolysin of Escherichia coli (HlyA) is a pore-forming protein, which is a prototype of the "Repeat in Toxins" (RTX) family. It was demonstrated that HlyA-cholesterol interaction facilitates the insertion of the toxin into membranes. Putative cholesterol-binding sites, called cholesterol recognition/amino acid consensus (CRAC), and CARC (analogous to CRAC but with the opposite orientation) were identified in the HlyA sequence. In this context, two peptides were synthesized, one derived from a CARC site from the insertion domain of the toxin (residues 341-353) (PEP 1) and the other one from a CRAC site from the domain between the acylated lysines (residues 639-644) (PEP 2), to study their role in the interaction of HlyA with membranes. The interaction of peptides with membranes of different lipid compositions (pure POPC and POPC/Cho of 4:1 and 2:1 molar ratios) was analyzed by surface plasmon resonance and molecular dynamics simulations. Results demonstrate that both peptides interact preferentially with Cho-containing membranes, although PEP 2 presents a lower KD than PEP 1. Molecular dynamics simulation results indicate that the insertion and interaction of PEP 2 with Cho-containing membranes are more prominent than those caused by PEP 1. The hemolytic activity of HlyA in the presence of peptides indicates that PEP 2 was the only one that inhibits HlyA activity, interfering in the binding between the toxin and cholesterol.
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Affiliation(s)
- Lucía Cané
- CCT-La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), 60 y 120, La Plata 1900, Argentina
| | - Fanny Guzmán
- Núcleo de Biotecnología Curauma (NBC), Pontificia Universidad Católica de Valparaíso, Valparaíso 2373223, Chile
| | - Galo Balatti
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes. Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Roque Sáenz Peña 352, Bernal, Buenos Aires 1876, Argentina
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Metabolismo del Fármaco (IQUIMEFA). Junín 956, Buenos Aires 1113, Argentina
| | - María Antonieta Daza Millone
- CCT-La Plata, CONICET. Universidad Nacional de La Plata, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Sucursal 4 Casilla de Correo 16, La Plata 1900, Argentina
| | - Melisa Pucci Molineris
- CCT-La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), 60 y 120, La Plata 1900, Argentina
| | - Sabina Maté
- CCT-La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), 60 y 120, La Plata 1900, Argentina
| | - M Florencia Martini
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Metabolismo del Fármaco (IQUIMEFA). Junín 956, Buenos Aires 1113, Argentina
- Cátedra de Química Medicinal, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires 1113, Argentina
| | - Vanesa Herlax
- CCT-La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), 60 y 120, La Plata 1900, Argentina
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4
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Hodges FJ, Torres VVL, Cunningham AF, Henderson IR, Icke C. Redefining the bacterial Type I protein secretion system. Adv Microb Physiol 2023; 82:155-204. [PMID: 36948654 DOI: 10.1016/bs.ampbs.2022.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Type I secretion systems (T1SS) are versatile molecular machines for protein transport across the Gram-negative cell envelope. The archetypal Type I system mediates secretion of the Escherichia coli hemolysin, HlyA. This system has remained the pre-eminent model of T1SS research since its discovery. The classic description of a T1SS is composed of three proteins: an inner membrane ABC transporter, a periplasmic adaptor protein and an outer membrane factor. According to this model, these components assemble to form a continuous channel across the cell envelope, an unfolded substrate molecule is then transported in a one-step mechanism, directly from the cytosol to the extracellular milieu. However, this model does not encapsulate the diversity of T1SS that have been characterized to date. In this review, we provide an updated definition of a T1SS, and propose the subdivision of this system into five subgroups. These subgroups are categorized as T1SSa for RTX proteins, T1SSb for non-RTX Ca2+-binding proteins, T1SSc for non-RTX proteins, T1SSd for class II microcins, and T1SSe for lipoprotein secretion. Although often overlooked in the literature, these alternative mechanisms of Type I protein secretion offer many avenues for biotechnological discovery and application.
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Affiliation(s)
- Freya J Hodges
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Von Vergel L Torres
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Adam F Cunningham
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Ian R Henderson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.
| | - Christopher Icke
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.
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5
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Dubey S, Ager-Wick E, Peng B, Evensen Ø, Sørum H, Munang’andu HM. Characterization of virulence and antimicrobial resistance genes of Aeromonas media strain SD/21-15 from marine sediments in comparison with other Aeromonas spp. Front Microbiol 2022; 13:1022639. [PMID: 36532448 PMCID: PMC9752117 DOI: 10.3389/fmicb.2022.1022639] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 10/06/2022] [Indexed: 10/03/2023] Open
Abstract
Aeromonas media is a Gram-negative bacterium ubiquitously found in aquatic environments. It is a foodborne pathogen associated with diarrhea in humans and skin ulceration in fish. In this study, we used whole genome sequencing to profile all antimicrobial resistance (AMR) and virulence genes found in A. media strain SD/21-15 isolated from marine sediments in Denmark. To gain a better understanding of virulence and AMR genes found in several A. media strains, we included 24 whole genomes retrieved from the public databanks whose isolates originate from different host species and environmental samples from Asia, Europe, and North America. We also compared the virulence genes of strain SD/21-15 with A. hydrophila, A. veronii, and A. salmonicida reference strains. We detected Msh pili, tap IV pili, and lateral flagella genes responsible for expression of motility and adherence proteins in all isolates. We also found hylA, hylIII, and TSH hemolysin genes in all isolates responsible for virulence in all isolates while the aerA gene was not detected in all A. media isolates but was present in A. hydrophila, A. veronii, and A. salmonicida reference strains. In addition, we detected LuxS and mshA-Q responsible for quorum sensing and biofilm formation as well as the ferric uptake regulator (Fur), heme and siderophore genes responsible for iron acquisition in all A. media isolates. As for the secretory systems, we found all genes that form the T2SS in all isolates while only the vgrG1, vrgG3, hcp, and ats genes that form parts of the T6SS were detected in some isolates. Presence of bla MOX-9 and bla OXA-427 β-lactamases as well as crp and mcr genes in all isolates is suggestive that these genes were intrinsically encoded in the genomes of all A. media isolates. Finally, the presence of various transposases, integrases, recombinases, virulence, and AMR genes in the plasmids examined in this study is suggestive that A. media has the potential to transfer virulence and AMR genes to other bacteria. Overall, we anticipate these data will pave way for further studies on virulence mechanisms and the role of A. media in the spread of AMR genes.
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Affiliation(s)
- Saurabh Dubey
- Section for Experimental Biomedicine, Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Eirill Ager-Wick
- Section for Experimental Biomedicine, Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Bo Peng
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Higher Education Mega Center, Guangzhou, China
| | - Øystein Evensen
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Henning Sørum
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Hetron Mweemba Munang’andu
- Section for Experimental Biomedicine, Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
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6
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Fernández-Vázquez J, Cabrer-Panes JD, Åberg A, Juárez A, Madrid C, Gaviria-Cantin T, Fernández-Coll L, Vargas-Sinisterra AF, Jiménez CJ, Balsalobre C. ppGpp, the General Stress Response Alarmone, Is Required for the Expression of the α-Hemolysin Toxin in the Uropathogenic Escherichia coli Isolate, J96. Int J Mol Sci 2022; 23:ijms232012256. [PMID: 36293122 PMCID: PMC9602796 DOI: 10.3390/ijms232012256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 11/08/2022] Open
Abstract
ppGpp is an intracellular sensor that, in response to different types of stress, coordinates the rearrangement of the gene expression pattern of bacteria to promote adaptation and survival to new environmental conditions. First described to modulate metabolic adaptive responses, ppGpp modulates the expression of genes belonging to very diverse functional categories. In Escherichia coli, ppGpp regulates the expression of cellular factors that are important during urinary tract infections. Here, we characterize the role of this alarmone in the regulation of the hlyCABDII operon of the UPEC isolate J96, encoding the toxin α-hemolysin that induces cytotoxicity during infection of bladder epithelial cells. ppGpp is required for the expression of the α-hemolysin encoded in hlyCABDII by stimulating its transcriptional expression. Prototrophy suppressor mutations in a ppGpp-deficient strain restore the α-hemolysin expression from this operon to wild-type levels, confirming the requirement of ppGpp for its expression. ppGpp stimulates hlyCABDII expression independently of RpoS, RfaH, Zur, and H-NS. The expression of hlyCABDII is promoted at 37 °C and at low osmolarity. ppGpp is required for the thermoregulation but not for the osmoregulation of the hlyCABDII operon. Studies in both commensal and UPEC isolates demonstrate that no UPEC specific factor is strictly required for the ppGpp-mediated regulation described. Our data further support the role of ppGpp participating in the coordinated regulation of the expression of bacterial factors required during infection.
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Affiliation(s)
- Jorge Fernández-Vázquez
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Juan David Cabrer-Panes
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Anna Åberg
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Antonio Juárez
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - Cristina Madrid
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Tania Gaviria-Cantin
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Llorenç Fernández-Coll
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | | | - Carlos Jonay Jiménez
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Carlos Balsalobre
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
- Correspondence: ; Tel.: +34-934-034-622
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7
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Filipi K, Rahman WU, Osickova A, Osicka R. Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins. Microorganisms 2022; 10:microorganisms10030518. [PMID: 35336094 PMCID: PMC8953716 DOI: 10.3390/microorganisms10030518] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/04/2022] Open
Abstract
The Gram-negative bacterium Kingella kingae is part of the commensal oropharyngeal flora of young children. As detection methods have improved, K. kingae has been increasingly recognized as an emerging invasive pathogen that frequently causes skeletal system infections, bacteremia, and severe forms of infective endocarditis. K. kingae secretes an RtxA cytotoxin, which is involved in the development of clinical infection and belongs to an ever-growing family of cytolytic RTX (Repeats in ToXin) toxins secreted by Gram-negative pathogens. All RTX cytolysins share several characteristic structural features: (i) a hydrophobic pore-forming domain in the N-terminal part of the molecule; (ii) an acylated segment where the activation of the inactive protoxin to the toxin occurs by a co-expressed toxin-activating acyltransferase; (iii) a typical calcium-binding RTX domain in the C-terminal portion of the molecule with the characteristic glycine- and aspartate-rich nonapeptide repeats; and (iv) a C-proximal secretion signal recognized by the type I secretion system. RTX toxins, including RtxA from K. kingae, have been shown to act as highly efficient ‘contact weapons’ that penetrate and permeabilize host cell membranes and thus contribute to the pathogenesis of bacterial infections. RtxA was discovered relatively recently and the knowledge of its biological role remains limited. This review describes the structure and function of RtxA in the context of the most studied RTX toxins, the knowledge of which may contribute to a better understanding of the action of RtxA in the pathogenesis of K. kingae infections.
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8
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Giglione C, Meinnel T. Mapping the myristoylome through a complete understanding of protein myristoylation biochemistry. Prog Lipid Res 2021; 85:101139. [PMID: 34793862 DOI: 10.1016/j.plipres.2021.101139] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/04/2021] [Accepted: 11/06/2021] [Indexed: 12/22/2022]
Abstract
Protein myristoylation is a C14 fatty acid modification found in all living organisms. Myristoylation tags either the N-terminal alpha groups of cysteine or glycine residues through amide bonds or lysine and cysteine side chains directly or indirectly via glycerol thioester and ester linkages. Before transfer to proteins, myristate must be activated into myristoyl coenzyme A in eukaryotes or, in bacteria, to derivatives like phosphatidylethanolamine. Myristate originates through de novo biosynthesis (e.g., plants), from external uptake (e.g., human tissues), or from mixed origins (e.g., unicellular organisms). Myristate usually serves as a molecular anchor, allowing tagged proteins to be targeted to membranes and travel across endomembrane networks in eukaryotes. In this review, we describe and discuss the metabolic origins of protein-bound myristate. We review strategies for in vivo protein labeling that take advantage of click-chemistry with reactive analogs, and we discuss new approaches to the proteome-wide discovery of myristate-containing proteins. The machineries of myristoylation are described, along with how protein targets can be generated directly from translating precursors or from processed proteins. Few myristoylation catalysts are currently described, with only N-myristoyltransferase described to date in eukaryotes. Finally, we describe how viruses and bacteria hijack and exploit myristoylation for their pathogenicity.
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Affiliation(s)
- Carmela Giglione
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
| | - Thierry Meinnel
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
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9
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Lipidation of Class IV CdiA Effector Proteins Promotes Target Cell Recognition during Contact-Dependent Growth Inhibition. mBio 2021; 12:e0253021. [PMID: 34634941 PMCID: PMC8510554 DOI: 10.1128/mbio.02530-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Contact-dependent growth inhibition (CDI) systems enable the direct transfer of protein toxins between competing Gram-negative bacteria. CDI+ strains produce cell surface CdiA effector proteins that bind specific receptors on neighboring bacteria to initiate toxin delivery. Three classes of CdiA effectors that recognize different outer membrane protein receptors have been characterized in Escherichia coli to date. Here, we describe a fourth effector class that uses the lipopolysaccharide (LPS) core as a receptor to identify target bacteria. Selection for CDI-resistant target cells yielded waaF and waaP “deep-rough” mutants, which are unable to synthesize the full LPS core. The CDI resistance phenotypes of other waa mutants suggest that phosphorylated inner-core heptose residues form a critical CdiA recognition epitope. Class IV cdi loci also encode putative lysyl acyltransferases (CdiC) that are homologous to enzymes that lipidate repeats-in-toxin (RTX) cytolysins. We found that catalytically active CdiC is required for full target cell killing activity, and we provide evidence that the acyltransferase appends 3-hydroxydecanoate to a specific Lys residue within the CdiA receptor-binding domain. We propose that the lipid moiety inserts into the hydrophobic leaflet of lipid A to anchor CdiA interactions with the core oligosaccharide. Thus, LPS-binding CDI systems appear to have co-opted an RTX toxin-activating acyltransferase to increase the affinity of CdiA effectors for the target cell outer membrane.
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10
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Zhang P, Essendoubi S, Keenliside J, Reuter T, Stanford K, King R, Lu P, Yang X. Genomic analysis of Shiga toxin-producing Escherichia coli O157:H7 from cattle and pork-production related environments. NPJ Sci Food 2021; 5:15. [PMID: 34210979 PMCID: PMC8249597 DOI: 10.1038/s41538-021-00097-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/06/2021] [Indexed: 02/04/2023] Open
Abstract
Three E. coli O157:H7 outbreaks have been attributed to contaminated pork in Alberta, Canada, recently. This study investigates the phylogenetic relatedness of E. coli O157:H7 from pigs, cattle, and pork-production environments for source attribution. Limited strain diversity was observed using five conventional subtyping methods, with most or all strains being in one subgroup. Whole-genome single nucleotide polymorphism analysis confirmed the recent ancestry of the isolates from all three sources. Most environmental isolates clustered closer with pig isolates than cattle isolates. Also, a direct link was observed between 2018-outbreak environmental isolates and isolates collected from a pig farm in 2018. The majority of pig isolates harbor only one Shiga toxin gene, stx2a, while 70% (35/50) of the cattle isolates have both stx1a and stx2a. The results show some E. coli O157:H7 strains could establish persistence on pig farms and as such, pigs can be a significant source of the organism.
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Affiliation(s)
- Peipei Zhang
- grid.55614.330000 0001 1302 4958Agriculture and Agri-Food Canada, Lacombe, Alberta Canada
| | | | | | - Tim Reuter
- Alberta Agriculture and Forestry, Lethbridge, Alberta Canada ,grid.47609.3c0000 0000 9471 0214University of Lethbridge, Lethbridge, Alberta Canada
| | - Kim Stanford
- Alberta Agriculture and Forestry, Lethbridge, Alberta Canada ,grid.47609.3c0000 0000 9471 0214University of Lethbridge, Lethbridge, Alberta Canada
| | - Robin King
- Alberta Agriculture and Forestry, Edmonton, Alberta Canada
| | - Patricia Lu
- Alberta Agriculture and Forestry, Edmonton, Alberta Canada
| | - Xianqin Yang
- grid.55614.330000 0001 1302 4958Agriculture and Agri-Food Canada, Lacombe, Alberta Canada
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11
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Ahangarpour M, Kavianinia I, Harris PWR, Brimble MA. Photo-induced radical thiol-ene chemistry: a versatile toolbox for peptide-based drug design. Chem Soc Rev 2021; 50:898-944. [PMID: 33404559 DOI: 10.1039/d0cs00354a] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
While the global market for peptide/protein-based therapeutics is witnessing significant growth, the development of peptide drugs remains challenging due to their low oral bioavailability, poor membrane permeability, and reduced metabolic stability. However, a toolbox of chemical approaches has been explored for peptide modification to overcome these obstacles. In recent years, there has been a revival of interest in photoinduced radical thiol-ene chemistry as a powerful tool for the construction of therapeutic peptides.
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Affiliation(s)
- Marzieh Ahangarpour
- School of Chemical Sciences, The University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand.
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12
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Preferential modification of CyaA-hemolysin by CyaC-acyltransferase through the catalytic Ser 30-His 33 dyad in esterolysis of palmitoyl-donor substrate devoid of acyl carrier proteins. Arch Biochem Biophys 2020; 694:108615. [PMID: 33011179 DOI: 10.1016/j.abb.2020.108615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 09/04/2020] [Accepted: 09/29/2020] [Indexed: 11/23/2022]
Abstract
We previously demonstrated that the ~130-kDa CyaA-hemolysin domain (CyaA-Hly) from Bordetella pertussis co-expressed with CyaC-acyltransferase in Escherichia coli was acylated at Lys983 and thus activated its hemolytic activity. Here, attempts were made to provide greater insights into such toxin activation via fatty-acyl modification by CyaC-acyltransferase. Non-acylated CyaA-Hly (NA/CyaA-Hly) and CyaC were separately expressed in E. coli and subsequently purified by FPLC to near homogeneity. When effects of acyl-chain length were comparatively evaluated through CyaC-esterolysis using various p-nitrophenyl (pNP) derivatives, Michaelis-Menten steady-state kinetic parameters (KM and kcat) of CyaC-acyltransferase revealed a marked preference for myristoyl (C14:0) and palmitoyl (C16:0) substrates of which catalytic efficiencies (kcat/KM) were roughly the same (~1.5 × 103 s-1mM-1). However, pNP-palmitate (pNPP) gave the highest hemolytic activity of NA/CyaA-Hly after being acylated in vitro with a range of acyl-donor substrates. LC-MS/MS analysis confirmed such CyaC-mediated palmitoylation of CyaA-Hly occurring at Lys983, denoting no requirement of an acyl carrier protein (ACP). A homology-based CyaC structure inferred a role of a potential catalytic dyad of conserved Ser30 and His33 residues in substrate esterolysis. CyaC-ligand binding analysis via molecular docking corroborated high-affinity binding of palmitate with its carboxyl group oriented toward such a dyad. Ala-substitutions of each residue (S30A or H33A) caused a drastic decrease in kcat/KM of CyaC toward pNPP, and hence its catalytic malfunction through palmitoylation-dependent activation of NA/CyaA-Hly. Altogether, our present data evidently provide such preferential palmitoylation of CyaA-Hly by CyaC-acyltransferase through the enzyme Ser30-His33 nucleophile-activation dyad in esterolysis of palmitoyl-donor substrate, particularly devoid of a natural acyl-ACP donor.
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13
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Reid LO, Thomas AH, Herlax V, Dántola ML. Role of Tryptophan Residues in the Toxicity and Photosensitized Inactivation of Escherichia coli α-Hemolysin. Biochemistry 2020; 59:4213-4224. [PMID: 33108867 DOI: 10.1021/acs.biochem.0c00660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
α-Hemolysin (HlyA) is an extracellular protein toxin secreted by uropathogenic strains of Escherichia coli that inserts into membranes of eukaryotic cells. The main goal of this work was to investigate the involvement of tryptophan (W) residues in the hemolytic activity of HlyA. We investigated the hemolytic activity of six single-point mutant proteins, in which one of the four Ws was replaced by cysteine (C) or leucine (L). We also analyzed the photoinactivation of HlyA with pterin (Ptr), an endogenous photosensitizer, as a method of unspecific oxidation of W and tyrosine (Y) residues. HlyA photoinactivation was analyzed by ultraviolet-visible spectrophotometry, hemolytic activity measurement, fluorescence spectroscopy, and electrophoretic analysis. The results indicate that Ws are important in the hemolytic process. Specifically, the chemical structure of the amino acid at position 578 is important for the acylation of HlyA at residue K563. Furthermore, the exposure of HlyA to ultraviolet radiation, with energy similar to that experienced under sun exposure, in the presence of Ptr induces the inactivation of the toxin, causing chemical changes in, at least, W and Y, the rate of damage to W residues being faster than that observed for Y residues. This work not only deepens our understanding of the structure-function relationship of the toxin but also introduces the possibility of using photoinactivation of HlyA for potential applications such as obtaining innocuous molecules for vaccine production and the elimination of the toxin from contaminated surfaces and drinking water.
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Affiliation(s)
- Lara O Reid
- Instituto de Investigaciones Fisicoquı́micas Teóricas y Aplicadas (INIFTA), Departamento de Quı́mica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT La Plata-CONICET, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina
| | - Andrés H Thomas
- Instituto de Investigaciones Fisicoquı́micas Teóricas y Aplicadas (INIFTA), Departamento de Quı́mica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT La Plata-CONICET, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina
| | - Vanesa Herlax
- Instituto de Investigaciones Bioquı́micas La Plata (INIBIOLP), CCT-La Plata, CONICET, UNLP, Facultad de Ciencias Médicas, 60 y 120 La Plata, 1900 La Plata, Argentina
| | - M Laura Dántola
- Instituto de Investigaciones Fisicoquı́micas Teóricas y Aplicadas (INIFTA), Departamento de Quı́mica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT La Plata-CONICET, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina
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14
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Abstract
Sulfhemoglobinemia (SulfHb) is a rare dyshemoglobinemia that can present with cyanosis in the absence of respiratory distress. It has been reported secondary to drug ingestion and chronic constipation. We present a case of SulfHb in an adolescent female with spina bifida and neurogenic bladder in the setting of an Escherichia coli urinary tract infection. An arterial blood gas differentiated a dyshemoglobinemia from other causes of hypoxemia. The resolution was achieved with antibiotics and red cell transfusion. Here we review the pathophysiology of SulfHb and contribute a unique case report to the limited body of literature on this topic.
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15
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Induction of erythrocyte microvesicles by Escherichia Coli Alpha hemolysin. Biochem J 2020; 476:3455-3473. [PMID: 31661116 DOI: 10.1042/bcj20190546] [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] [Received: 07/29/2019] [Revised: 10/03/2019] [Accepted: 10/29/2019] [Indexed: 01/11/2023]
Abstract
Alpha hemolysin (HlyA) is the major virulence factor of uropathogenic Escherichia coli (UPEC) strains. Once in circulation, a low concentration of the toxin induces an increase in intracellular calcium that activates calpains - which proteolyse cytoskeleton proteins - and also favours the exposure of phosphatidylserine (PS) in the outer leaflet of erythrocyte membranes. All these events are considered part of eryptosis, as well as the delivery of microvesicles (MVs). Within this context, we studied the delivery of MVs by erythrocytes treated with sublytic concentrations of HlyA and demonstrated that HlyA-treated erythrocytes secrete MVs of diameter ∼200 nm containing HlyA and PS by a mechanism involving an increment of intracellular calcium concentration and purinergic receptor activation. Despite the presence of toxin in their membrane, HlyA-MVs are not hemolytically active and do not induce ATP release in untreated erythrocytes, thus suggesting that the delivery of HlyA-MVs might act as a protective mechanism on the part of erythrocytes that removes the toxin from the membrane to prevent the spread of infection. Although erythrocytes have been found to eliminate denatured hemoglobin and several membrane proteins by shedding MVs, the present work has revealed for the first time that an exogenous protein, such as a toxin, is eliminated by this process. This finding sheds light on the mechanism of action of the toxin and serves to further elucidate the consequences of UPEC infection in patients exhibiting HlyA-related diseases.
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16
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Geng Z, Huang J, Kang L, Gao S, Yuan Y, Li Y, Wang J, Xin W, Wang J. Clostridium perfringens epsilon toxin binds to erythrocyte MAL receptors and triggers phosphatidylserine exposure. J Cell Mol Med 2020; 24:7341-7352. [PMID: 32463157 PMCID: PMC7339222 DOI: 10.1111/jcmm.15315] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 01/23/2020] [Accepted: 01/27/2020] [Indexed: 12/12/2022] Open
Abstract
Epsilon toxin (ETX) is a 33-kDa pore-forming toxin produced by type B and D strains of Clostridium perfringens. We previously found that ETX caused haemolysis of human red blood cells, but not of erythrocytes from other species. The cellular and molecular mechanisms of ETX-mediated haemolysis are not well understood. Here, we investigated the effects of ETX on erythrocyte volume and the role of the putative myelin and lymphocyte (MAL) receptors in ETX-mediated haemolysis. We observed that ETX initially decreased erythrocyte size, followed by a gradual increase in volume until lysis. Moreover, ETX triggered phosphatidylserine (PS) exposure and enhanced ceramide abundance in erythrocytes. Cell shrinkage, PS exposure and enhanced ceramide abundance were preceded by increases in intracellular Ca2+ concentration. Interestingly, lentivirus-mediated RNA interference studies in the human erythroleukaemia cell line (HEL) cells confirmed that MAL contributes to ETX-induced cytotoxicity. Additionally, ETX was shown to bind to MAL in vitro. The results of this study recommend that ETX-mediated haemolysis is associated with MAL receptor activation in human erythrocytes. These data imply that interventions affecting local MAL-mediated autocrine and paracrine signalling may prevent ETX-mediated erythrocyte damage.
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Affiliation(s)
- Zhijun Geng
- Graduate College, Anhui Medical University, Anhui, China.,State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, AMMS, Beijing, China
| | - Jing Huang
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, AMMS, Beijing, China.,Life Science Institute of Hebei Normal University, Shijiazhuang, China
| | - Lin Kang
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, AMMS, Beijing, China
| | - Shan Gao
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, AMMS, Beijing, China
| | - Yuan Yuan
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, AMMS, Beijing, China
| | - Yanwei Li
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, AMMS, Beijing, China
| | - Jing Wang
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, AMMS, Beijing, China
| | - Wenwen Xin
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, AMMS, Beijing, China
| | - Jinglin Wang
- Graduate College, Anhui Medical University, Anhui, China.,State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, AMMS, Beijing, China
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17
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Park BS, Lee N. A bivalent fusion vaccine composed of recombinant Apx proteins shows strong protection against Actinobacillus pleuroneumoniae serovar 1 and 2 in a mouse model. Pathog Dis 2020; 77:5426212. [PMID: 30939190 DOI: 10.1093/femspd/ftz020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 03/31/2019] [Indexed: 11/12/2022] Open
Abstract
Actinobacillus pleuropneumonia (APP) causes porcine pleuropneumoniae, resulting in severe economic losses in the swine industry. Since there are diverse serotypes of APP, it is necessary for vaccines to induce cross-protection. In this report, we developed a bivalent fusion vaccine, the L vaccine composed of ApxIA and ApxIIA fragments. According to the experimental results of the L vaccine, recombinant protein specific-IgG antibody level increased significantly as well as Apx toxin specific-IgG antibody, suggesting toxin-neutralizing effect. Also, the production of both IgG1 and IgG2a indicates this fusion vaccine induces Th1 and Th2 immune reactions. In addition, lymphocytes were proliferated and immune related-cytokines of TNF-α, IL-12, IFN-γ and IL-5 were detected in the serum after the vaccination. The L vaccine showed a perfect cross-protection against APP serovar 1 and 2 that each secrete different Apx exotoxins. These findings reveal that the fusion L vaccine induces specific humoral and cellular immunity, leading to a perfect cross-protection against A. pleuropneumoniae infections in a murine model.
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Affiliation(s)
- Byung-Sun Park
- Technology Institute, KBNP, Inc., Anyang, Gyeonggi, South Korea
| | - Nakhyung Lee
- Technology Institute, KBNP, Inc., Anyang, Gyeonggi, South Korea
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18
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Aggregatibacter actinomycetemcomitans LtxA Hijacks Endocytic Trafficking Pathways in Human Lymphocytes. Pathogens 2020; 9:pathogens9020074. [PMID: 31973183 PMCID: PMC7168647 DOI: 10.3390/pathogens9020074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 12/11/2022] Open
Abstract
Leukotoxin (LtxA), from oral pathogen Aggregatibacter actinomycetemcomitans, is a secreted membrane-damaging protein. LtxA is internalized by β2 integrin LFA-1 (CD11a/CD18)-expressing leukocytes and ultimately causes cell death; however, toxin localization in the host cell is poorly understood and these studies fill this void. We investigated LtxA trafficking using multi-fluor confocal imaging, flow cytometry and Rab5a knockdown in human T lymphocyte Jurkat cells. Planar lipid bilayers were used to characterize LtxA pore-forming activity at different pHs. Our results demonstrate that the LtxA/LFA-1 complex gains access to the cytosol of Jurkat cells without evidence of plasma membrane damage, utilizing dynamin-dependent and presumably clathrin-independent mechanisms. Upon internalization, LtxA follows the LFA-1 endocytic trafficking pathways, as identified by co-localization experiments with endosomal and lysosomal markers (Rab5, Rab11A, Rab7, and Lamp1) and CD11a. Knockdown of Rab5a resulted in the loss of susceptibility of Jurkat cells to LtxA cytotoxicity, suggesting that late events of LtxA endocytic trafficking are required for toxicity. Toxin trafficking via the degradative endocytic pathway may culminate in the delivery of the protein to lysosomes or its accumulation in Rab11A-dependent recycling endosomes. The ability of LtxA to form pores at acidic pH may result in permeabilization of the endosomal and lysosomal membranes.
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19
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Frey J. RTX Toxins of Animal Pathogens and Their Role as Antigens in Vaccines and Diagnostics. Toxins (Basel) 2019; 11:toxins11120719. [PMID: 31835534 PMCID: PMC6950323 DOI: 10.3390/toxins11120719] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 01/19/2023] Open
Abstract
Exotoxins play a central role in the pathologies caused by most major bacterial animal pathogens. The large variety of vertebrate and invertebrate hosts in the animal kingdom is reflected by a large variety of bacterial pathogens and toxins. The group of repeats in the structural toxin (RTX) toxins is particularly abundant among bacterial pathogens of animals. Many of these toxins are described as hemolysins due to their capacity to lyse erythrocytes in vitro. Hemolysis by RTX toxins is due to the formation of cation-selective pores in the cell membrane and serves as an important marker for virulence in bacterial diagnostics. However, their physiologic relevant targets are leukocytes expressing β2 integrins, which act as specific receptors for RTX toxins. For various RTX toxins, the binding to the CD18 moiety of β2 integrins has been shown to be host specific, reflecting the molecular basis of the host range of RTX toxins expressed by bacterial pathogens. Due to the key role of RTX toxins in the pathogenesis of many bacteria, antibodies directed against specific RTX toxins protect against disease, hence, making RTX toxins valuable targets in vaccine research and development. Due to their specificity, several structural genes encoding for RTX toxins have proven to be essential in modern diagnostic applications in veterinary medicine.
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Affiliation(s)
- Joachim Frey
- Vetsuisse Facutly, University of Bern, 3012 Bern, Switzerland
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20
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Vega BA, Belinka BA, Kachlany SC. Aggregatibacter actinomycetemcomitans Leukotoxin (LtxA; Leukothera ®): Mechanisms of Action and Therapeutic Applications. Toxins (Basel) 2019; 11:toxins11090489. [PMID: 31454891 PMCID: PMC6784247 DOI: 10.3390/toxins11090489] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/21/2019] [Accepted: 08/22/2019] [Indexed: 12/18/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans is an oral pathogen that produces the RTX toxin, leukotoxin (LtxA; Leukothera®). A. actinomycetemcomitans is strongly associated with the development of localized aggressive periodontitis. LtxA acts as a virulence factor for A. actinomycetemcomitans to subvert the host immune response by binding to the β2 integrin lymphocyte function-associated antigen-1 (LFA-1; CD11a/CD18) on white blood cells (WBCs), causing cell death. In this paper, we reviewed the state of knowledge on LtxA interaction with WBCs and the subsequent mechanisms of induced cell death. Finally, we touched on the potential therapeutic applications of LtxA (trade name Leukothera®) toxin therapy for the treatment of hematological malignancies and immune-mediated diseases.
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Affiliation(s)
- Brian A Vega
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ 07103, USA
- Actinobac Biomed, Inc., Princeton, NJ 08540, USA
| | | | - Scott C Kachlany
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ 07103, USA.
- Actinobac Biomed, Inc., Princeton, NJ 08540, USA.
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21
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Aggregatibacter actinomycetemcomitans Leukotoxin (LtxA) Requires Death Receptor Fas, in Addition to LFA-1, To Trigger Cell Death in T Lymphocytes. Infect Immun 2019; 87:IAI.00309-19. [PMID: 31109948 DOI: 10.1128/iai.00309-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 05/10/2019] [Indexed: 11/20/2022] Open
Abstract
Leukotoxin (LtxA) (trade name, Leukothera) is a protein secreted by the oral bacterium Aggregatibacter actinomycetemcomitans A. actinomycetemcomitans is an oral pathogen strongly associated with development of localized aggressive periodontitis. LtxA acts as a virulence factor for A. actinomycetemcomitans by binding to the β2 integrin lymphocyte function-associated antigen-1 (LFA-1; CD11a/CD18) on white blood cells (WBCs) and causing cell death. In addition, because of its specificity for malignant and activated WBCs, LtxA is being investigated as a therapeutic agent for treatment of hematological malignancies and autoimmune diseases. Here, we report the successful generation and characterization of Jurkat T lymphocytes with deletions in CD18, CD11a, and Fas that were engineered using CRISPR/Cas9 gene editing. Using these clones, we demonstrate the specificity of LtxA for cells expressing LFA-1. We also demonstrate the requirement of the cell death receptor Fas for LtxA-mediated cell death in T lymphocytes. We show that LFA-1 and Fas are early events in the LtxA-mediated cell death cascade as caspase activation and mitochondrial perturbation do not occur in the absence of either receptor. To our knowledge, LtxA is the first molecule, other than FasL, known to require the Fas death receptor to initiate cell death. Knowledge of the mechanism of cell death induced by LtxA will facilitate the understanding of LtxA as a bacterial virulence factor and development of it as a potential therapeutic agent.
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22
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Peherstorfer S, Brewitz HH, Paul George AA, Wißbrock A, Adam JM, Schmitt L, Imhof D. Insights into mechanism and functional consequences of heme binding to hemolysin-activating lysine acyltransferase HlyC from Escherichia coli. Biochim Biophys Acta Gen Subj 2018; 1862:1964-1972. [PMID: 29908817 DOI: 10.1016/j.bbagen.2018.06.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 01/01/2023]
Abstract
BACKGROUND Tight regulation of heme homeostasis is a critical mechanism in pathogenic bacteria since heme functions as iron source and prosthetic group, but is also toxic at elevated concentrations. Hemolysin-activating lysine-acyltransferase (HlyC) from Escherichia coli is crucial for maturation of hemolysin A, which lyses several mammalian cells including erythrocytes liberating large amounts of heme for bacterial uptake. A possible impact and functional consequences of the released heme on events employing bacterial HlyC have remained unexplored. METHODS Heme binding to HlyC was investigated using UV/vis and SPR spectroscopy. Functional impact of heme association was examined using an in vitro hemolysis assay. The interaction was further studied by homology modeling, molecular docking and dynamics simulations. RESULTS We identified HlyC as potential heme-binding protein possessing heme-regulatory motifs. Using wild-type protein and a double alanine mutant we demonstrated that heme binds to HlyC via histidine 151 (H151). We could show further that heme inhibits the enzymatic activity of wild-type HlyC. Computational studies illustrated potential interaction sites in addition to H151 confirming the results from spectroscopy indicating more than one heme-binding site. CONCLUSIONS Taken together, our results reveal novel insights into heme-protein interactions and regulation of a component of the heme uptake system in one of the major causative agents of urinary tract infections in humans. GENERAL SIGNIFICANCE This study points to a possible novel mechanism of regulation as present in many uropathogenic E. coli strains at an early stage of heme iron acquisition from erythrocytes for subsequent internalization by the bacterial heme-uptake machinery.
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Affiliation(s)
- Sandra Peherstorfer
- Institute of Biochemistry, University of Düsseldorf, 40255 Düsseldorf, Germany
| | - Hans Henning Brewitz
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany
| | - Ajay Abisheck Paul George
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany
| | - Amelie Wißbrock
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany
| | - Jana Maria Adam
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, University of Düsseldorf, 40255 Düsseldorf, Germany.
| | - Diana Imhof
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany.
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23
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Velasco E, Wang S, Sanet M, Fernández-Vázquez J, Jové D, Glaría E, Valledor AF, O'Halloran TV, Balsalobre C. A new role for Zinc limitation in bacterial pathogenicity: modulation of α-hemolysin from uropathogenic Escherichia coli. Sci Rep 2018; 8:6535. [PMID: 29695842 PMCID: PMC5916954 DOI: 10.1038/s41598-018-24964-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 04/09/2018] [Indexed: 11/30/2022] Open
Abstract
Metal limitation is a common situation during infection and can have profound effects on the pathogen’s success. In this report, we examine the role of zinc limitation in the expression of a virulence factor in uropathogenic Escherichia coli. The pyelonephritis isolate J96 carries two hlyCABD operons that encode the RTX toxin α-hemolysin. While the coding regions of both operons are largely conserved, the upstream sequences, including the promoters, are unrelated. We show here that the two hlyCABD operons are differently regulated. The hlyII operon is efficiently silenced in the presence of zinc and highly expressed when zinc is limited. In contrast, the hlyI operon does not respond to zinc limitation. Genetic studies reveal that zinc-responsive regulation of the hlyII operon is controlled by the Zur metalloregulatory protein. A Zur binding site was identified in the promoter sequence of the hlyII operon, and we observe direct binding of Zur to this promoter region. Moreover, we find that Zur regulation of the hlyII operon modulates the ability of E. coli J96 to induce a cytotoxic response in host cell lines in culture. Our report constitutes the first description of the involvement of the zinc-sensing protein Zur in directly modulating the expression of a virulence factor in bacteria.
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Affiliation(s)
- Elsa Velasco
- Department of Genetics, Microbiology and Statistics, School of Biology, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Suning Wang
- Chemistry of Life Process Institute, and Department of Chemistry, Northwestern University, Evanston, Illinois, 60208-3113, United States of America
| | - Marianna Sanet
- Department of Genetics, Microbiology and Statistics, School of Biology, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Jorge Fernández-Vázquez
- Department of Genetics, Microbiology and Statistics, School of Biology, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Daniel Jové
- Department of Genetics, Microbiology and Statistics, School of Biology, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Estibaliz Glaría
- Nuclear Receptor Group, Department of Cell Biology, Physiology and Immunology, School of Biology, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Annabel F Valledor
- Nuclear Receptor Group, Department of Cell Biology, Physiology and Immunology, School of Biology, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Thomas V O'Halloran
- Chemistry of Life Process Institute, and Department of Chemistry, Northwestern University, Evanston, Illinois, 60208-3113, United States of America
| | - Carlos Balsalobre
- Department of Genetics, Microbiology and Statistics, School of Biology, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain.
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24
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Elhosseiny NM, Attia AS. Acinetobacter: an emerging pathogen with a versatile secretome. Emerg Microbes Infect 2018; 7:33. [PMID: 29559620 PMCID: PMC5861075 DOI: 10.1038/s41426-018-0030-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/08/2017] [Accepted: 01/09/2018] [Indexed: 02/06/2023]
Abstract
Acinetobacter baumannii is a notorious pathogen that has emerged as a healthcare nightmare in recent years because it causes serious infections that are associated with high morbidity and mortality rates. Due to its exceptional ability to acquire resistance to almost all available antibiotics, A. baumannii is currently ranked as the first pathogen on the World Health Organization’s priority list for the development of new antibiotics. The versatile range of effectors secreted by A. baumannii represents a large proportion of the virulence arsenal identified in this bacterium to date. Thus, these factors, together with the secretory machinery responsible for their extrusion into the extracellular milieu, are key targets for novel therapeutics that are greatly needed to combat this deadly pathogen. In this review, we provide a comprehensive, up-to-date overview of the organization and regulatory aspects of the Acinetobacter secretion systems, with a special emphasis on their versatile substrates that could be targeted to fight the deadly infections caused by this elusive pathogen.
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Affiliation(s)
- Noha M Elhosseiny
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt
| | - Ahmed S Attia
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt.
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25
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Jiang H, Zhang X, Chen X, Aramsangtienchai P, Tong Z, Lin H. Protein Lipidation: Occurrence, Mechanisms, Biological Functions, and Enabling Technologies. Chem Rev 2018; 118:919-988. [PMID: 29292991 DOI: 10.1021/acs.chemrev.6b00750] [Citation(s) in RCA: 275] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Protein lipidation, including cysteine prenylation, N-terminal glycine myristoylation, cysteine palmitoylation, and serine and lysine fatty acylation, occurs in many proteins in eukaryotic cells and regulates numerous biological pathways, such as membrane trafficking, protein secretion, signal transduction, and apoptosis. We provide a comprehensive review of protein lipidation, including descriptions of proteins known to be modified and the functions of the modifications, the enzymes that control them, and the tools and technologies developed to study them. We also highlight key questions about protein lipidation that remain to be answered, the challenges associated with answering such questions, and possible solutions to overcome these challenges.
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Affiliation(s)
- Hong Jiang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiaoyu Zhang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiao Chen
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Pornpun Aramsangtienchai
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Zhen Tong
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Hening Lin
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
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Vázquez RF, Daza Millone MA, Pavinatto FJ, Herlax VS, Bakás LS, Oliveira ON, Vela ME, Maté SM. Interaction of acylated and unacylated forms of E. coli alpha-hemolysin with lipid monolayers: a PM-IRRAS study. Colloids Surf B Biointerfaces 2017; 158:76-83. [PMID: 28683345 DOI: 10.1016/j.colsurfb.2017.06.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/12/2017] [Accepted: 06/19/2017] [Indexed: 11/18/2022]
Abstract
Uropathogenic strains of Escherichia coli produce virulence factors, such as the protein toxin alpha-hemolysin (HlyA), that enable the bacteria to colonize the host and establish an infection. HlyA is synthetized as a protoxin (ProHlyA) that is transformed into the active form in the bacterial cytosol by the covalent linkage of two fatty-acyl moieties to the polypeptide chain before the secretion of HlyA into the extracellular medium. The aim of this work was to investigate the effect of the fatty acylation of HlyA on protein conformation and protein-membrane interactions. Polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS) experiments were performed at the air-water interface, and lipid monolayers mimicking the outer leaflet of red-blood-cell membranes were used as model systems for the study of protein-membrane interaction. According to surface-pressure measurements, incorporation of the acylated protein into the lipid films was faster than that of the nonacylated form. PM-IRRAS measurements revealed that the adsorption of the proteins to the lipid monolayers induced disorder in the lipid acyl chains and also changed the elastic properties of the films independently of protein acylation. No significant difference was observed between HlyA and ProHlyA in the interaction with the model lipid monolayers; but when these proteins became adsorbed on a bare air-water interface, they adopted different secondary structures. The assumption of the correct protein conformation at a hydrophobic-hydrophilic interface could constitute a critical condition for biologic activity.
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Affiliation(s)
- Romina F Vázquez
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET. Facultad de Ciencias Médicas. Universidad Nacional de La Plata, 60 y 120, 1900, La Plata, Argentina
| | - María A Daza Millone
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT- La Plata, CONICET. Universidad Nacional de La Plata, Sucursal 4 Casilla de Correo 16, 1900, La Plata, Argentina
| | - Felippe J Pavinatto
- Instituto de Física de São Carlos (IFSC), Universidade de São Paulo, SP, Brazil
| | - Vanesa S Herlax
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET. Facultad de Ciencias Médicas. Universidad Nacional de La Plata, 60 y 120, 1900, La Plata, Argentina
| | - Laura S Bakás
- Centro de Investigación de Proteínas Vegetales (CIPROVE), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas. Universidad Nacional de La Plata. 47 y 115, 1900, La Plata, Argentina
| | - Osvaldo N Oliveira
- Instituto de Física de São Carlos (IFSC), Universidade de São Paulo, SP, Brazil
| | - María E Vela
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT- La Plata, CONICET. Universidad Nacional de La Plata, Sucursal 4 Casilla de Correo 16, 1900, La Plata, Argentina
| | - Sabina M Maté
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET. Facultad de Ciencias Médicas. Universidad Nacional de La Plata, 60 y 120, 1900, La Plata, Argentina.
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Viala JP, Prima V, Puppo R, Agrebi R, Canestrari MJ, Lignon S, Chauvin N, Méresse S, Mignot T, Lebrun R, Bouveret E. Acylation of the Type 3 Secretion System Translocon Using a Dedicated Acyl Carrier Protein. PLoS Genet 2017; 13:e1006556. [PMID: 28085879 PMCID: PMC5279801 DOI: 10.1371/journal.pgen.1006556] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 01/30/2017] [Accepted: 12/29/2016] [Indexed: 12/18/2022] Open
Abstract
Bacterial pathogens often deliver effectors into host cells using type 3 secretion systems (T3SS), the extremity of which forms a translocon that perforates the host plasma membrane. The T3SS encoded by Salmonella pathogenicity island 1 (SPI-1) is genetically associated with an acyl carrier protein, IacP, whose role has remained enigmatic. In this study, using tandem affinity purification, we identify a direct protein-protein interaction between IacP and the translocon protein SipB. We show, by mass spectrometry and radiolabelling, that SipB is acylated, which provides evidence for a modification of the translocon that has not been described before. A unique and conserved cysteine residue of SipB is identified as crucial for this modification. Although acylation of SipB was not essential to virulence, we show that this posttranslational modification promoted SipB insertion into host-cell membranes and pore-forming activity linked to the SPI-1 T3SS. Cooccurrence of acyl carrier and translocon proteins in several γ- and β-proteobacteria suggests that acylation of the translocon is conserved in these other pathogenic bacteria. These results also indicate that acyl carrier proteins, known for their involvement in metabolic pathways, have also evolved as cofactors of new bacterial protein lipidation pathways. Acyl carrier proteins are small ubiquitous proteins involved in the synthesis of hydrocarbon based molecules. Notably, they are essential for the synthesis of fatty acids, which are the precursors of membrane phospholipids. They can also be involved in secondary metabolism, for example for the synthesis of molecules with antibacterial properties. Although acyl carrier proteins are widespread, the specific role of each individual protein seems comparatively poorly explored. In this study, we investigate the role of an acyl carrier protein genetically associated with a type 3 secretion system (T3SS). Many Gram-negative bacterial pathogens use T3SS to deliver effectors directly into the cytoplasm of eukaryotic host cells and to subvert host cellular pathways. For this purpose, the translocon, which is the terminal part of T3SS, forms a pore inserted into the host-cell membrane. Here we show that the acyl carrier protein associated with the T3SS has specialized to allow acylation of the translocon. The novel posttranslational modification of the translocon that we describe optimizes insertion into the host-cell membrane and pore-forming activity. This mechanism is likely to be conserved in other pathogenic bacteria given the conserved genetic association between T3SS and acyl carrier protein in several bacteria.
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Affiliation(s)
- Julie P. Viala
- Aix Marseille Univ, CNRS, IMM, LISM, Marseille, France
- * E-mail:
| | - Valérie Prima
- Aix Marseille Univ, CNRS, IMM, LISM, Marseille, France
| | - Rémy Puppo
- Aix Marseille Univ, CNRS, IMM, Proteomic Platform- IBISA, Marseille, France
| | - Rym Agrebi
- Aix Marseille Univ, CNRS, IMM, LCB, Marseille, France
| | | | - Sabrina Lignon
- Aix Marseille Univ, CNRS, IMM, Proteomic Platform- IBISA, Marseille, France
| | | | | | - Tâm Mignot
- Aix Marseille Univ, CNRS, IMM, LCB, Marseille, France
| | - Régine Lebrun
- Aix Marseille Univ, CNRS, IMM, Proteomic Platform- IBISA, Marseille, France
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de Freitas MCR, Resende JA, Ferreira-Machado AB, Saji GDRQ, de Vasconcelos ATR, da Silva VL, Nicolás MF, Diniz CG. Exploratory Investigation of Bacteroides fragilis Transcriptional Response during In vitro Exposure to Subinhibitory Concentration of Metronidazole. Front Microbiol 2016; 7:1465. [PMID: 27703449 PMCID: PMC5028390 DOI: 10.3389/fmicb.2016.01465] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 09/01/2016] [Indexed: 12/29/2022] Open
Abstract
Bacteroides fragilis, member from commensal gut microbiota, is an important pathogen associated to endogenous infections and metronidazole remains a valuable antibiotic for the treatment of these infections, although bacterial resistance is widely reported. Considering the need of a better understanding on the global mechanisms by which B. fragilis survive upon metronidazole exposure, we performed a RNA-seq transcriptomic approach with validation of gene expression results by qPCR. Bacteria strains were selected after in vitro subcultures with subinhibitory concentration (SIC) of the drug. From a wild type B. fragilis ATCC 43859 four derivative strains were selected: first and fourth subcultures under metronidazole exposure and first and fourth subcultures after drug removal. According to global gene expression analysis, 2,146 protein coding genes were identified, of which a total of 1,618 (77%) were assigned to a Gene Ontology term (GO), indicating that most known cellular functions were taken. Among these 2,146 protein coding genes, 377 were shared among all strains, suggesting that they are critical for B. fragilis survival. In order to identify distinct expression patterns, we also performed a K-means clustering analysis set to 15 groups. This analysis allowed us to detect the major activated or repressed genes encoding for enzymes which act in several metabolic pathways involved in metronidazole response such as drug activation, defense mechanisms against superoxide ions, high expression level of multidrug efflux pumps, and DNA repair. The strains collected after metronidazole removal were functionally more similar to those cultured under drug pressure, reinforcing that drug-exposure lead to drastic persistent changes in the B. fragilis gene expression patterns. These results may help to elucidate B. fragilis response during metronidazole exposure, mainly at SIC, contributing with information about bacterial survival strategies under stress conditions in their environment.
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Affiliation(s)
- Michele C R de Freitas
- Departamento de Parasitologia, Microbiologia e Imunologia, Universidade Federal de Juiz de Fora Juiz de Fora, Brazil
| | - Juliana A Resende
- Departamento de Parasitologia, Microbiologia e Imunologia, Universidade Federal de Juiz de Fora Juiz de Fora, Brazil
| | - Alessandra B Ferreira-Machado
- Departamento de Parasitologia, Microbiologia e Imunologia, Universidade Federal de Juiz de Fora Juiz de Fora, Brazil
| | - Guadalupe D R Q Saji
- Laboratório de Bioinformática and Laboratório Nacional de Computação Científica Petrópolis, Brazil
| | - Ana T R de Vasconcelos
- Laboratório de Bioinformática and Laboratório Nacional de Computação Científica Petrópolis, Brazil
| | - Vânia L da Silva
- Departamento de Parasitologia, Microbiologia e Imunologia, Universidade Federal de Juiz de Fora Juiz de Fora, Brazil
| | - Marisa F Nicolás
- Laboratório de Bioinformática and Laboratório Nacional de Computação Científica Petrópolis, Brazil
| | - Cláudio G Diniz
- Departamento de Parasitologia, Microbiologia e Imunologia, Universidade Federal de Juiz de Fora Juiz de Fora, Brazil
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Schagdarsurengin U, Western P, Steger K, Meinhardt A. Developmental origins of male subfertility: role of infection, inflammation, and environmental factors. Semin Immunopathol 2016; 38:765-781. [PMID: 27315198 DOI: 10.1007/s00281-016-0576-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 06/06/2016] [Indexed: 12/28/2022]
Abstract
Male gamete development begins with the specification of primordial cells in the epiblast of the early embryo and is not complete until spermatozoa mature in the epididymis of adult males. This protracted developmental process involves extensive alteration of the paternal germline epigenome. Initially, epigenetic reprogramming in fetal germ cells results in removal of most DNA methylation, including parent-specific epigenetic information. The germ cells then establish sex-specific epigenetic information through de novo methylation and undergo spermatogenesis. Chromatin in haploid germ cells is repackaged into protamines during spermiogenesis, providing further widespread epigenetic reorganization. Finally, after fertilization, epigenetic reprogramming in the preimplantation embryo is necessary for regaining totipotency. These events provide substantial windows during which epigenetic errors either may be corrected or may occur in the germline. There is now increasing evidence that environmental factors such as exposure to toxicants, the parents' and individual's diet, and even infectious and inflammatory events in the male reproductive tract may influence epigenetic reprogramming. This, together with other damage inflicted on the germline chromatin, may result in negative consequences for fertility and health. Large epidemiological birth cohort studies have yielded insight into possible causative environmental factors. Together with experimental animal studies, a clearer view of environmental impacts on fetal development and their intergenerational and even transgenerational effects on reproductive health has emerged and is reviewed in this article.
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Affiliation(s)
- Undraga Schagdarsurengin
- Department of Urology, Pediatric Urology and Andrology, Section Molecular Andrology, Justus-Liebig University of Giessen, Giessen, Germany
| | - Patrick Western
- Centre for Genetic Diseases, Hudson Institute for Medical Research and Department of Molecular and Translational Science, Monash University, Clayton, VIC, 3168, Australia
| | - Klaus Steger
- Department of Urology, Pediatric Urology and Andrology, Section Molecular Andrology, Justus-Liebig University of Giessen, Giessen, Germany
| | - Andreas Meinhardt
- Institute of Anatomy and Cell Biology, Unit of Reproductive Biology, Justus-Liebig University of Giessen, Aulweg 123, 35385, Giessen, Germany.
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30
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Vázquez RF, Maté SM, Bakás LS, Muñoz-Garay C, Herlax VS. Relationship between intracellular calcium and morphologic changes in rabbit erythrocytes: Effects of the acylated and unacylated forms of E. coli alpha-hemolysin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1944-53. [PMID: 27206406 DOI: 10.1016/j.bbamem.2016.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/15/2016] [Accepted: 05/16/2016] [Indexed: 12/28/2022]
Affiliation(s)
- Romina F Vázquez
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, 1900 La Plata, Argentina
| | - Sabina M Maté
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, 1900 La Plata, Argentina
| | - Laura S Bakás
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900 La Plata, Argentina
| | - Carlos Muñoz-Garay
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (UNAM), Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, Mexico
| | - Vanesa S Herlax
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, 1900 La Plata, Argentina.
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31
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Murphy K, Ryan C, Dempsey EM, O'Toole PW, Ross RP, Stanton C, Ryan CA. Neonatal Sulfhemoglobinemia and Hemolytic Anemia Associated With Intestinal Morganella morganii. Pediatrics 2015; 136:e1641-5. [PMID: 26553186 DOI: 10.1542/peds.2015-0996] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/10/2015] [Indexed: 11/24/2022] Open
Abstract
Sulfhemoglobinemia is a rare disorder characterized by the presence of sulfhemoglobin in the blood. It is typically drug-induced and may cause hypoxia, end-organ damage, and death through oxygen deprivation. We present here a case of non-drug-induced sulfhemoglobinemia in a 7-day-old preterm infant complicated by hemolytic anemia. Microbiota compositional analysis of fecal samples to investigate the origin of hydrogen sulphide revealed the presence of Morganella morganii at a relative abundance of 38% of the total fecal microbiota at the time of diagnosis. M morganii was not detected in the fecal samples of 40 age-matched control preterm infants. M morganii is an opportunistic pathogen that can cause serious infection, particularly in immunocompromised hosts such as neonates. Strains of M morganii are capable of producing hydrogen sulphide, and virulence factors include the production of a diffusible α-hemolysin. The infant in this case survived intact through empirical oral and intravenous antibiotic therapy, probiotic administration, and red blood cell transfusions. This coincided with a reduction in the relative abundance of M morganii to 3%. Neonatologists should have a high index of suspicion for intestinal pathogens in cases of non-drug-induced sulfhemoglobinemia and consider empirical treatment of the intestinal microbiota in this potentially lethal condition.
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Affiliation(s)
- Kiera Murphy
- Food Biosciences Department, Teagasc Food Research Centre, Moorepark, Co Cork, Ireland; School of Microbiology, APC Microbiome Institute
| | - Clodagh Ryan
- Department of Haematology, Mercy University Hospital, Cork, Ireland; and
| | - Eugene M Dempsey
- Department of Neonatology, Cork University Maternity Hospital, Cork, Ireland INFANT Centre, and
| | | | - R Paul Ross
- APC Microbiome Institute, College of Science, Engineering and Food Science, University College Cork, Cork, Ireland
| | - Catherine Stanton
- Food Biosciences Department, Teagasc Food Research Centre, Moorepark, Co Cork, Ireland; APC Microbiome Institute
| | - C Anthony Ryan
- APC Microbiome Institute, Department of Neonatology, Cork University Maternity Hospital, Cork, Ireland
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32
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Gavin HE, Satchell KJF. MARTX toxins as effector delivery platforms. Pathog Dis 2015; 73:ftv092. [PMID: 26472741 DOI: 10.1093/femspd/ftv092] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2015] [Indexed: 12/14/2022] Open
Abstract
Bacteria frequently manipulate their host environment via delivery of microbial 'effector' proteins to the cytosol of eukaryotic cells. In the case of the multifunctional autoprocessing repeats-in-toxins (MARTX) toxin, this phenomenon is accomplished by a single, >3500 amino acid polypeptide that carries information for secretion, translocation, autoprocessing and effector activity. MARTX toxins are secreted from bacteria by dedicated Type I secretion systems. The released MARTX toxins form pores in target eukaryotic cell membranes for the delivery of up to five cytopathic effectors, each of which disrupts a key cellular process. Targeted cellular processes include modulation or modification of small GTPases, manipulation of host cell signaling and disruption of cytoskeletal integrity. More recently, MARTX toxins have been shown to be capable of heterologous protein translocation. Found across multiple bacterial species and genera--frequently in pathogens lacking Type 3 or Type 4 secretion systems--MARTX toxins in multiple cases function as virulence factors. Innovative research at the intersection of toxin biology and bacterial genetics continues to elucidate the intricacies of the toxin as well as the cytotoxic mechanisms of its diverse effector collection.
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Affiliation(s)
- Hannah E Gavin
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Karla J F Satchell
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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33
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Moore EK, Hopmans EC, Rijpstra WIC, Sánchez-Andrea I, Villanueva L, Wienk H, Schoutsen F, Stams AJM, Sinninghe Damsté JS. Lysine and novel hydroxylysine lipids in soil bacteria: amino acid membrane lipid response to temperature and pH in Pseudopedobacter saltans. Front Microbiol 2015; 6:637. [PMID: 26175720 PMCID: PMC4484230 DOI: 10.3389/fmicb.2015.00637] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 06/12/2015] [Indexed: 01/08/2023] Open
Abstract
Microbial decomposition of organic matter is an essential process in the global carbon cycle. The soil bacteria Pseudopedobacter saltans and Flavobacterium johnsoniae are both able to degrade complex organic molecules, but it is not fully known how their membrane structures are adapted to their environmental niche. The membrane lipids of these species were extracted and analyzed using high performance liquid chromatography-electrospray ionization/ion trap/mass spectrometry (HPLC-ESI/IT/MS) and high resolution accurate mass/mass spectrometry (HRAM/MS). Abundant unknown intact polar lipids (IPLs) from P. saltans were isolated and further characterized using amino acid analysis and two dimensional nuclear magnetic resonance (NMR) spectroscopy. Ornithine IPLs (OLs) with variable (hydroxy) fatty acid composition were observed in both bacterial species. Lysine-containing IPLs (LLs) were also detected in both species and were characterized here for the first time using HPLC-MS. Novel LLs containing hydroxy fatty acids and novel hydroxylysine lipids with variable (hydroxy) fatty acid composition were identified in P. saltans. The confirmation of OL and LL formation in F. johnsoniae and P. saltans and the presence of OlsF putative homologs in P. saltans suggest the OlsF gene coding protein is possibly involved in OL and LL biosynthesis in both species, however, potential pathways of OL and LL hydroxylation in P. saltans are still undetermined. Triplicate cultures of P. saltans were grown at three temperature/pH combinations: 30°C/pH 7, 15°C/pH 7, and 15°C/pH 9. The fractional abundance of total amino acid containing IPLs containing hydroxylated fatty acids was significantly higher at higher temperature, and the fractional abundance of lysine-containing IPLs was significantly higher at lower temperature and higher pH. These results suggest that these amino acid-containing IPLs, including the novel hydroxylysine lipids, could be involved in temperature and pH stress response of soil bacteria.
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Affiliation(s)
- Eli K. Moore
- Department of Marine Organic Biogeochemistry, Royal Netherlands Institute for Sea ResearchTexel, Netherlands
| | - Ellen C. Hopmans
- Department of Marine Organic Biogeochemistry, Royal Netherlands Institute for Sea ResearchTexel, Netherlands
| | - W. Irene C. Rijpstra
- Department of Marine Organic Biogeochemistry, Royal Netherlands Institute for Sea ResearchTexel, Netherlands
| | | | - Laura Villanueva
- Department of Marine Organic Biogeochemistry, Royal Netherlands Institute for Sea ResearchTexel, Netherlands
| | - Hans Wienk
- NMR Spectroscopy Research Group, Bijvoet Center for Biomolecular Research, Utrecht UniversityUtrecht, Netherlands
| | | | - Alfons J. M. Stams
- Laboratory of Microbiology, Wageningen UniversityWageningen, Netherlands
| | - Jaap S. Sinninghe Damsté
- Department of Marine Organic Biogeochemistry, Royal Netherlands Institute for Sea ResearchTexel, Netherlands
- Faculty of Geosciences, Utrecht UniversityUtrecht, Netherlands
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Greene NP, Crow A, Hughes C, Koronakis V. Structure of a bacterial toxin-activating acyltransferase. Proc Natl Acad Sci U S A 2015; 112:E3058-66. [PMID: 26016525 PMCID: PMC4466738 DOI: 10.1073/pnas.1503832112] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Secreted pore-forming toxins of pathogenic Gram-negative bacteria such as Escherichia coli hemolysin (HlyA) insert into host-cell membranes to subvert signal transduction and induce apoptosis and cell lysis. Unusually, these toxins are synthesized in an inactive form that requires posttranslational activation in the bacterial cytosol. We have previously shown that the activation mechanism is an acylation event directed by a specialized acyl-transferase that uses acyl carrier protein (ACP) to covalently link fatty acids, via an amide bond, to specific internal lysine residues of the protoxin. We now reveal the 2.15-Å resolution X-ray structure of the 172-aa ApxC, a toxin-activating acyl-transferase (TAAT) from pathogenic Actinobacillus pleuropneumoniae. This determination shows that bacterial TAATs are a structurally homologous family that, despite indiscernible sequence similarity, form a distinct branch of the Gcn5-like N-acetyl transferase (GNAT) superfamily of enzymes that typically use acyl-CoA to modify diverse bacterial, archaeal, and eukaryotic substrates. A combination of structural analysis, small angle X-ray scattering, mutagenesis, and cross-linking defined the solution state of TAATs, with intermonomer interactions mediated by an N-terminal α-helix. Superposition of ApxC with substrate-bound GNATs, and assay of toxin activation and binding of acyl-ACP and protoxin peptide substrates by mutated ApxC variants, indicates the enzyme active site to be a deep surface groove.
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Affiliation(s)
- Nicholas P Greene
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
| | - Allister Crow
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
| | - Colin Hughes
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
| | - Vassilis Koronakis
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
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Mittal S, Sharma M, Chaudhary U. Study of virulence factors of uropathogenic Escherichia coli and its antibiotic susceptibility pattern. INDIAN J PATHOL MICR 2015; 57:61-4. [PMID: 24739833 DOI: 10.4103/0377-4929.130899] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
CONTEXT Urinary tract infection (UTI) is one of the most common nosocomial infections, caused by Escherichia coli. This study determined the presence of virulence factors in the organism and correlates it with the multi-drug resistance (MDR). AIMS The aim of the following study is to assess the virulence factors of uropathogenic E. coli and antibiotic susceptibility pattern. SETTINGS AND DESIGN This was a prospective study conducted in the Department of Microbiology in PT. B. D. Sharma, PGIMS, Rohtak. SUBJECTS AND METHODS The study was conducted over a period of 1 year. Urine samples received were processed as per standard microbiological procedures. Virulence factors such as hemolysin, hemagglutination, cell surface hydrophobicity, serum resistance, gelatinase and siderophore production were studied. The antimicrobial susceptibility was done as per Clinical and Laboratory Standard Institute Guidelines. STATISTICAL ANALYSIS USED The data was analyzed by using SPSS(Statistical Package for the social sciences) IBM Corporation version 17.0. A two sided P ≤ 0.05 was considered to be significant. RESULTS Hemolysin production was seen in 47.4%, hemagglutination in 74.8%, cell surface hydrophobicity in 61%, serum resistance in 59%, gelatinase in 67.5% and siderophore production in 88% isolates. Nitrofurantoin was found to be most effective followed by, gatifloxacin and gentamicin. Twenty nine percent (29.62%) isolates were MDR. CONCLUSIONS Therefore, the knowledge of virulence factors of E. coli and their antibiotic susceptibility pattern will help in better understanding of the organism and in the treatment of UTI.
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Affiliation(s)
- Seema Mittal
- Department of Microbiology, Pt. B.D. Sharm PGIMS, Rohtak, Haryana, India
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36
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Bárcena-Uribarri I, Benz R, Winterhalter M, Zakharian E, Balashova N. Pore forming activity of the potent RTX-toxin produced by pediatric pathogen Kingella kingae: Characterization and comparison to other RTX-family members. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1536-44. [PMID: 25858109 DOI: 10.1016/j.bbamem.2015.03.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 03/25/2015] [Accepted: 03/30/2015] [Indexed: 12/18/2022]
Abstract
Pediatric septic arthritis in patients under age of four is frequently caused by the oral Gram-negative bacterium Kingella kingae. This organism may be responsible for a severe form of infective endocarditis in otherwise healthy children and adults. A major virulence factor of K. kingae is RtxA, a toxin that belongs to the RTX (Repeats-in-ToXin) group of secreted pore forming toxins. To understand the RtxA effects on host cell membranes, the toxin activity was studied using planar lipid bilayers. K. kingae strain PYKK081 and its isogenic RtxA-deficient strain, KKNB100, were tested for their ability to form pores in artificial membranes of asolectin/n-decane. RtxA, purified from PYKK081, was able to rapidly form pores with an apparent diameter of 1.9nm as measured by the partition of nonelectrolytes in the pores. The RtxA channels are cation-selective and showed strong voltage-dependent gating. In contrast to supernatants of PYKK081, those of KKNB100 did not show any pore forming activity. We concluded that RtxA toxin is the only secreted protein from K. kingae forming large channels in host cell membranes where it induces cation flux leading to programmed cell death. Furthermore, our findings suggested that the planar lipid bilayer technique can effectively be used to test possible inhibitors of RTX toxin activity and to investigate the mechanism of the toxin binding to the membrane.
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Affiliation(s)
| | - Roland Benz
- Department of Life Science and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Mathias Winterhalter
- Department of Life Science and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Eleonora Zakharian
- Department of Cancer Biology & Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, USA
| | - Nataliya Balashova
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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DiFranco KM, Johnson-Farley N, Bertino JR, Elson D, Vega BA, Belinka BA, Kachlany SC. LFA-1-targeting Leukotoxin (LtxA; Leukothera®) causes lymphoma tumor regression in a humanized mouse model and requires caspase-8 and Fas to kill malignant lymphocytes. Leuk Res 2015; 39:649-56. [PMID: 25850729 DOI: 10.1016/j.leukres.2015.03.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 03/07/2015] [Accepted: 03/16/2015] [Indexed: 12/12/2022]
Abstract
Leukotoxin (LtxA) is a protein secreted from the oral bacterium Aggregatibacter actinomycetemcomitans. LtxA binds to the β2 integrin lymphocyte-associated function antigen-1 (LFA-1) on human white blood cells (WBCs), resulting in cell death. LtxA is currently under investigation as a novel therapy (Leukothera(®)) for treating hematologic malignancies and autoimmune diseases. We show here that LtxA has potent in vivo anti-lymphoma activity in mice. LtxA caused complete regression of B-cell tumors and promoted long-term survival of mice. The mechanism of LtxA-mediated killing of malignant lymphocytes was further examined. We found that LtxA kills malignant lymphocytes by a novel mechanism requiring the death receptor Fas and caspase-8, but not Fas ligand (FasL) or caspase-9. We also determined that LFA-1 and Fas are closely associated on the cell surface and this proximity of LFA-1 and Fas could explain how signaling through an integrin can lead to cell death. In addition to LFA-1, this work reveals a second surface protein, Fas, that is critical for LtxA-mediated cell death. Knowledge of the mechanism of cell death induced by LtxA will facilitate the development and understanding of this potent experimental therapeutic agent.
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Affiliation(s)
- Kristina M DiFranco
- From the Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ 07103, United States
| | | | - Joseph R Bertino
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ 08903, United States
| | - David Elson
- From the Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ 07103, United States
| | - Brian A Vega
- From the Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ 07103, United States
| | | | - Scott C Kachlany
- From the Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ 07103, United States; Actinobac Biomed, Inc., North Brunswick, NJ 08902, United States.
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Thomas S, Smits SHJ, Schmitt L. A simple in vitro acylation assay based on optimized HlyA and HlyC purification. Anal Biochem 2014; 464:17-23. [PMID: 25016191 DOI: 10.1016/j.ab.2014.07.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 06/26/2014] [Accepted: 07/01/2014] [Indexed: 11/29/2022]
Abstract
HlyA is a toxin secreted by uropathogenic Escherichia coli strains. HlyA belongs to the repeats in the toxin protein family and needs (i) a posttranslational, fatty acylation at two internal lysines by the acyltransferase HlyC and (ii) extracellular ion binding to achieve its active conformation. Both processes are not fully understood and experiments are often limited due to the low amounts of protein available. Here, we present an optimized purification protocol for the proteins involved in HlyA activation as well as a quick and nonradioactive assay for in vitro HlyA acylation. These may simplify future experiments, e.g., activity scanning and characterization of HlyA or HlyC mutants as demonstrated with single and double HlyA lysine mutants.
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Affiliation(s)
- Sabrina Thomas
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Sander H J Smits
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany.
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Hemolysin of enterohemorrhagic Escherichia coli: Structure, transport, biological activity and putative role in virulence. Int J Med Microbiol 2014; 304:521-9. [DOI: 10.1016/j.ijmm.2014.05.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 05/09/2014] [Accepted: 05/11/2014] [Indexed: 11/19/2022] Open
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40
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Maté SM, Vázquez RF, Herlax VS, Daza Millone MA, Fanani ML, Maggio B, Vela ME, Bakás LS. Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1832-41. [DOI: 10.1016/j.bbamem.2014.02.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 02/24/2014] [Accepted: 02/27/2014] [Indexed: 11/29/2022]
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41
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Handley KM, Bartels D, O'Loughlin EJ, Williams KH, Trimble WL, Skinner K, Gilbert JA, Desai N, Glass EM, Paczian T, Wilke A, Antonopoulos D, Kemner KM, Meyer F. The complete genome sequence for putative H2- and S-oxidizerCandidatusSulfuricurvum sp., assembledde novofrom an aquifer-derived metagenome. Environ Microbiol 2014; 16:3443-62. [DOI: 10.1111/1462-2920.12453] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 03/04/2014] [Indexed: 11/26/2022]
Affiliation(s)
- Kim M. Handley
- Department of Ecology and Evolution; University of Chicago; Chicago IL 60637 USA
- Institute for Genomics and Systems Biology; Argonne National Laboratory; Lemont IL 60439 USA
| | - Daniela Bartels
- Institute for Genomics and Systems Biology; Argonne National Laboratory; Lemont IL 60439 USA
- Computation Institute; University of Chicago; Chicago IL 60637 USA
| | | | - Kenneth H. Williams
- Earth Science Division; Lawrence Berkeley National Laboratory; Berkeley CA USA
| | - William L. Trimble
- Mathematics and Computer Science Division; Argonne National Laboratory; Lemont IL 60439 USA
| | - Kelly Skinner
- Biosciences Division; Argonne National Laboratory; Lemont IL 60439 USA
| | - Jack A. Gilbert
- Department of Ecology and Evolution; University of Chicago; Chicago IL 60637 USA
- Institute for Genomics and Systems Biology; Argonne National Laboratory; Lemont IL 60439 USA
- Biosciences Division; Argonne National Laboratory; Lemont IL 60439 USA
| | - Narayan Desai
- Mathematics and Computer Science Division; Argonne National Laboratory; Lemont IL 60439 USA
| | - Elizabeth M. Glass
- Computation Institute; University of Chicago; Chicago IL 60637 USA
- Mathematics and Computer Science Division; Argonne National Laboratory; Lemont IL 60439 USA
| | - Tobias Paczian
- Computation Institute; University of Chicago; Chicago IL 60637 USA
- Mathematics and Computer Science Division; Argonne National Laboratory; Lemont IL 60439 USA
| | - Andreas Wilke
- Computation Institute; University of Chicago; Chicago IL 60637 USA
- Mathematics and Computer Science Division; Argonne National Laboratory; Lemont IL 60439 USA
| | - Dionysios Antonopoulos
- Institute for Genomics and Systems Biology; Argonne National Laboratory; Lemont IL 60439 USA
- Biosciences Division; Argonne National Laboratory; Lemont IL 60439 USA
| | - Kenneth M. Kemner
- Biosciences Division; Argonne National Laboratory; Lemont IL 60439 USA
| | - Folker Meyer
- Institute for Genomics and Systems Biology; Argonne National Laboratory; Lemont IL 60439 USA
- Computation Institute; University of Chicago; Chicago IL 60637 USA
- Mathematics and Computer Science Division; Argonne National Laboratory; Lemont IL 60439 USA
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RTX toxin plays a key role in Kingella kingae virulence in an infant rat model. Infect Immun 2014; 82:2318-28. [PMID: 24664507 DOI: 10.1128/iai.01636-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Kingella kingae is a human oral bacterium that can cause diseases of the skeletal system in children and infective endocarditis in children and adults. K. kingae produces a toxin of the RTX group, RtxA. To investigate the role of RtxA in disease pathogenesis in vivo, K. kingae strain PYKK081 and its isogenic RtxA-deficient strain KKNB100 were tested for their virulence and pathological consequences upon intraperitoneal injections in 7-day-postnatal (PN 7) rats. At the doses above 8.0 × 10(6) cells/animal, PYKK081 was able to cause a fatal illness, resulting in rapid weight loss, bacteremia, and abdominal necrotic lesion formation. Significant histopathology was observed in thymus, spleen, and bone marrow. Strain KKNB100 was less toxic to animals. Neither weight loss, bacteremia, nor histopathological changes were evident. Animals injected with KKNB100 exhibited a significantly elevated circulating white blood cell (WBC) count, whereas animals injected with PYKK081 had a WBC count that resembled that of the uninfected control. This observation parallels the subtleties associated with clinical presentation of K. kingae disease in humans and suggests that the toxin contributes to WBC depletion. Thus, our results demonstrate that RtxA is a key K. kingae virulence factor. Furthermore, our findings suggest that the PN 7 rat can serve as a useful model for understanding disease caused by K. kingae and for elucidating diagnostic parameters in human patients.
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43
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Novel evidence for the specific interaction between cholesterol and α-haemolysin of Escherichia coli. Biochem J 2014; 458:481-9. [DOI: 10.1042/bj20131432] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The present study shows, for the first time, the interaction of HlyA with cholesterol. This interaction seems to favour a conformational state of the protein that allows its correct insertion into the membrane and its further oligomerization to form pores.
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Wille T, Wagner C, Mittelstädt W, Blank K, Sommer E, Malengo G, Döhler D, Lange A, Sourjik V, Hensel M, Gerlach RG. SiiA and SiiB are novel type I secretion system subunits controlling SPI4-mediated adhesion ofSalmonella enterica. Cell Microbiol 2013; 16:161-78. [DOI: 10.1111/cmi.12222] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 09/25/2013] [Accepted: 09/27/2013] [Indexed: 12/28/2022]
Affiliation(s)
- Thorsten Wille
- Nachwuchsgruppe 3; RKI Bereich Wernigerode; Wernigerode Germany
| | - Carolin Wagner
- Mikrobiologisches Institut; Universitätsklinikum Erlangen; Erlangen Germany
- Abt. Mikrobiologie; Universität Osnabrück; Osnabrück Germany
| | | | - Kathrin Blank
- Nachwuchsgruppe 3; RKI Bereich Wernigerode; Wernigerode Germany
| | - Erik Sommer
- Zentrum für Molekulare Biologie der Universität Heidelberg; DKFZ-ZMBH-Alliance; Heidelberg Germany
| | - Gabriele Malengo
- Zentrum für Molekulare Biologie der Universität Heidelberg; DKFZ-ZMBH-Alliance; Heidelberg Germany
| | - Daniela Döhler
- Mikrobiologisches Institut; Universitätsklinikum Erlangen; Erlangen Germany
| | - Anna Lange
- Nachwuchsgruppe 3; RKI Bereich Wernigerode; Wernigerode Germany
| | - Viktor Sourjik
- Zentrum für Molekulare Biologie der Universität Heidelberg; DKFZ-ZMBH-Alliance; Heidelberg Germany
| | - Michael Hensel
- Abt. Mikrobiologie; Universität Osnabrück; Osnabrück Germany
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45
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Acyl Transfer from Membrane Lipids to Peptides Is a Generic Process. J Mol Biol 2013; 425:4379-87. [DOI: 10.1016/j.jmb.2013.07.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 06/24/2013] [Accepted: 07/10/2013] [Indexed: 12/24/2022]
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46
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Thomas S, Holland IB, Schmitt L. The Type 1 secretion pathway - the hemolysin system and beyond. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1629-41. [PMID: 24129268 DOI: 10.1016/j.bbamcr.2013.09.017] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/21/2013] [Accepted: 09/23/2013] [Indexed: 12/27/2022]
Abstract
Type 1 secretion systems (T1SS) are wide-spread among Gram-negative bacteria. An important example is the secretion of the hemolytic toxin HlyA from uropathogenic strains. Secretion is achieved in a single step directly from the cytosol to the extracellular space. The translocation machinery is composed of three indispensable membrane proteins, two in the inner membrane, and the third in the outer membrane. The inner membrane proteins belong to the ABC transporter and membrane fusion protein families (MFPs), respectively, while the outer membrane component is a porin-like protein. Assembly of the three proteins is triggered by accumulation of the transport substrate (HlyA) in the cytoplasm, to form a continuous channel from the inner membrane, bridging the periplasm and finally to the exterior. Interestingly, the majority of substrates of T1SS contain all the information necessary for targeting the polypeptide to the translocation channel - a specific sequence at the extreme C-terminus. Here, we summarize our current knowledge of regulation, channel assembly, translocation of substrates, and in the case of the HlyA toxin, its interaction with host membranes. We try to provide a complete picture of structure function of the components of the translocation channel and their interaction with the substrate. Although we will place the emphasis on the paradigm of Type 1 secretion systems, the hemolysin A secretion machinery from E. coli, we also cover as completely as possible current knowledge of other examples of these fascinating translocation systems. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Affiliation(s)
- Sabrina Thomas
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstr, 1, 40225 Düsseldorf, Germany
| | - I Barry Holland
- Institute of Genetics and Microbiology, CNRS UMR 8621, University Paris-Sud XI, Building 409, 91405 Orsay Cedex, France
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstr, 1, 40225 Düsseldorf, Germany.
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Lang T, Dechant M, Sanchez V, Wistuba J, Boiani M, Pilatz A, Stammler A, Middendorff R, Schuler G, Bhushan S, Tchatalbachev S, Wübbeling F, Burger M, Chakraborty T, Mallidis C, Meinhardt A. Structural and functional integrity of spermatozoa is compromised as a consequence of acute uropathogenic E. coli-associated epididymitis. Biol Reprod 2013; 89:59. [PMID: 23843239 DOI: 10.1095/biolreprod.113.110379] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Uropathogenic Escherichia coli (UPEC)-associated epididymitis is commonly diagnosed in outpatient settings. Although the infection can be successfully cleared using antimicrobial medications, 40% of patients unexplainably show persistent impaired semen parameters even after treatment. Our aim was to investigate whether pathogenic UPEC and its associated virulence factor hemolysin (hlyA) perturb the structural and functional integrity of both the epididymis and sperm, actions that may be responsible for the observed impairment and possibly a reduction of fertilization capabilities. Semen collected from patients diagnosed with E. coli-only related epididymitis showed that sperm counts were low 14 days postantimicrobial treatment regardless of hlyA status. At Day 84 following treatment, hlyA production correlated with approximately 4-fold lower sperm concentrations than in men with hlyA-negative strains. In vivo experiments with the hlyA-producing UPEC CFT073 strain in a murine epididymitis model showed that just 3 days postinfection, structural damage to the epididymis (epithelial damage, leukocyte infiltration, and edema formation) was present. This was more severe in UPEC CFT073 compared to nonpathogenic E. coli (NPEC 470) infection. Moreover, pathogenic UPEC strains prematurely activated the acrosome in vivo and in vitro. Raman microspectroscopy revealed that UPEC CFT073 undermined sperm integrity by inducing nuclear DNA damage. Consistent with these observations, the in vitro fertilization capability of hlyA-treated mouse sperm was completely abolished, although sperm were motile. These findings provide new insights into understanding the possible processes underlying clinical manifestations of acute epididymitis.
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Affiliation(s)
- Tali Lang
- Department of Anatomy and Cell Biology, Justus-Liebig-University Giessen, Germany
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Posttranslational maturation of the invasion acyl carrier protein of Salmonella enterica serovar Typhimurium requires an essential phosphopantetheinyl transferase of the fatty acid biosynthesis pathway. J Bacteriol 2013; 195:4399-405. [PMID: 23893113 DOI: 10.1128/jb.00472-13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Salmonella pathogenicity island 1 (SPI-1) carries genes required for the formation of a type 3 secretion system, which is necessary for the invasion process of Salmonella. Among the proteins encoded by SPI-1 is IacP, a homolog of acyl carrier proteins. Acyl carrier proteins are mainly involved in fatty acid biosynthesis, and they require posttranslational maturation by addition of a 4'-phosphopantetheine prosthetic group to be functional. In this study, we analyzed IacP maturation in vivo. By performing matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry analysis of intact purified proteins, we showed that IacP from Salmonella enterica serovar Typhimurium was matured by addition of 4'-phosphopantetheine to the conserved serine 38 residue. Therefore, we searched for the phosphopantetheinyl transferases in charge of IacP maturation. A bacterial two-hybrid approach revealed that IacP interacted with AcpS, an enzyme normally required for the maturation of the canonical acyl carrier protein (ACP), which is involved in fatty acid biosynthesis. The creation of a conditional acpS mutant then demonstrated that AcpS was necessary for the maturation of IacP. However, although IacP was similar to ACP and matured by using the same enzyme, IacP could not replace the essential function of ACP in fatty acid synthesis. Hence, the demonstration that IacP is matured by AcpS establishes a cross-connection between virulence and fatty acid biosynthesis pathways.
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49
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Momtaz H, Jamshidi A. Shiga toxin-producing Escherichia coli isolated from chicken meat in Iran: serogroups, virulence factors, and antimicrobial resistance properties. Poult Sci 2013; 92:1305-13. [PMID: 23571340 DOI: 10.3382/ps.2012-02542] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The aim of the current study was to determine the virulence factors, serogroups, and antibiotic resistance properties of Shiga toxin-producing Escherichia coli isolated from chicken meat samples. A total of 422 chicken meat samples were collected from 5 townships of Iran. Specimens were immediately transferred to the laboratory in a cooler with an ice pack. Samples were cultured, and the positive culture samples were analyzed by PCR assays. Finally, the antimicrobial susceptibility test was performed using the disk diffusion method in Mueller-Hinton agar. According to the results, out of 422 samples, 146 (34.59%) were confirmed to be E. coli positive and among E. coli-positive samples, 51 (34.93%) and 31 (21.23%) were from attaching and effacing E. coli (AEEC) and enterohemorrhagic E. coli (EHEC) subgroups, respectively. All of the EHEC-positive samples had all stx1, eaeA, and ehly virulence genes, whereas only 5 (9.80%) of AEEC subgroup had all stx1, stx2, and eaeA genes. As the data revealed, O157 was the most prevalent and O111 was the least prevalent strains in the Shiga toxin-producing E. coli (STEC) population. Among STEC strains, sulI and blaSHV had the highest and lowest incidence rate, respectively. There was a high resistance to tetracycline (76.82%), followed by chloramphenicol (73.17%) and nitrofurantoin (63.41%), but there was low resistance to cephalotine (7.31%) antibiotics in isolated strains. Results shows that the PCR technique has a high performance for detection of serogroups, virulence genes, and antibiotic resistance genes in STEC strains. This study is the first prevalence report of detection of virulence genes, serogroups, and antibiotic resistance properties of STEC strains isolated from chicken meat samples in Iran. Based on the results, chicken meat is one of the main sources of STEC strains and its virulence factors in Iran, so an accurate meat inspection would reduce disease outbreaks.
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Affiliation(s)
- Hassan Momtaz
- College of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.
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50
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Brown AC, Balashova NV, Epand RM, Epand RF, Bragin A, Kachlany SC, Walters MJ, Du Y, Boesze-Battaglia K, Lally ET. Aggregatibacter actinomycetemcomitans leukotoxin utilizes a cholesterol recognition/amino acid consensus site for membrane association. J Biol Chem 2013; 288:23607-21. [PMID: 23792963 DOI: 10.1074/jbc.m113.486654] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans produces a repeats-in-toxin (RTX) leukotoxin (LtxA) that selectively kills human immune cells. Binding of LtxA to its β2 integrin receptor (lymphocyte function-associated antigen-1 (LFA-1)) results in the clustering of the toxin·receptor complex in lipid rafts. Clustering occurs only in the presence of LFA-1 and cholesterol, and LtxA is unable to kill cells lacking either LFA-1 or cholesterol. Here, the interaction of LtxA with cholesterol was measured using surface plasmon resonance and differential scanning calorimetry. The binding of LtxA to phospholipid bilayers increased by 4 orders of magnitude in the presence of 40% cholesterol relative to the absence of cholesterol. The affinity was specific to cholesterol and required an intact secondary structure. LtxA contains two cholesterol recognition/amino acid consensus (CRAC) sites; CRAC(336) ((333)LEEYSKR(339)) is highly conserved among RTX toxins, whereas CRAC(503) ((501)VDYLK(505)) is unique to LtxA. A peptide corresponding to CRAC(336) inhibited the ability of LtxA to kill Jurkat (Jn.9) cells. Although peptides corresponding to both CRAC(336) and CRAC(503) bind cholesterol, only CRAC(336) competitively inhibited LtxA binding to this sterol. A panel of full-length LtxA CRAC mutants demonstrated that an intact CRAC(336) site was essential for LtxA cytotoxicity. The conservation of CRAC(336) among RTX toxins suggests that this mechanism may be conserved among RTX toxins.
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Affiliation(s)
- Angela C Brown
- Department of Pathology, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania 19104, USA
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