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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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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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Abstract
PURPOSE OF REVIEW RTX toxin action often defines the outcome of bacterial infections. Here, we discuss the progress in understanding the impacts of RTX toxin activities on host immunity. RECENT FINDINGS Bordetella pertussis CyaA activity paralyzes sentinel phagocytic cells by elevating cellular cAMP levels and blocks differentiation of infiltrating monocytes into bactericidal macrophages, promoting also de-differentiation of resident alveolar macrophages into monocyte-like cells. Vibrio cholerae multifunctional autoprocessing repeats-in-toxins (MARTX), through Rho inactivating and α/β-hydrolase (ABH) domain action blocks mitogen-activated protein kinase signaling in epithelial cells and dampens the inflammatory responses of intestinal epithelia by blocking immune cell recruitment. The action of actin crosslinking effector domain and Ras/Rap1-specific endopeptidase (RRSP) domains of MARTX compromises the phagocytic ability of macrophages. Aggregatibacter actinomycetemcomitans LtxA action triggers neutrophil elastase release into periodontal tissue, compromising the epithelial barrier and promoting bacterial spreads into deeper tissue. SUMMARY Action of RTX toxins enables bacterial pathogens to cope with the fierce host immune defenses. RTX toxins often block phagocytosis and bactericidal reactive oxygen species and NO production. Some RTX toxins can reprogram the macrophages to less bactericidal cell types. Autophagy is hijacked for example by the activity of the V. cholerae ABH effector domain of the MARTX protein. Subversion of immune functions by RTX toxins thus promotes bacterial survival and proliferation in the host.
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Verma V, Kumar P, Gupta S, Yadav S, Dhanda RS, Thorlacius H, Yadav M. α-Hemolysin of uropathogenic E. coli regulates NLRP3 inflammasome activation and mitochondrial dysfunction in THP-1 macrophages. Sci Rep 2020; 10:12653. [PMID: 32724079 PMCID: PMC7387347 DOI: 10.1038/s41598-020-69501-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 07/07/2020] [Indexed: 12/16/2022] Open
Abstract
Hemolysin expressing UPEC strains have been associated with severe advanced kidney pathologies, such as cystitis and pyelonephritis, which are associated with an inflammatory response. Macrophages play an important role in regulating an inflammatory response during a urinary tract infection. We have studied the role of purified recombinant α-hemolysin in inducing inflammatory responses and cell death in macrophages. Acylation at lysine residues through HlyC is known to activate proHlyA into a fully functional pore-forming toxin, HlyA. It was observed that active α-hemolysin (HlyA) induced cleavage of caspase-1 leading to the maturation of IL-1β, while inactive α-hemolysin (proHlyA) failed to do so in THP-1 derived macrophages. HlyA also promotes deubiquitination, oligomerization, and activation of the NLRP3 inflammasome, which was found to be dependent on potassium efflux. We have also observed the co-localization of NLRP3 within mitochondria during HlyA stimulations. Moreover, blocking of potassium efflux improved the mitochondrial health in addition to a decreased inflammatory response. Our study demonstrates that HlyA stimulation caused perturbance in potassium homeostasis, which led to the mitochondrial dysfunction followed by an acute inflammatory response, resulting in cell death. However, the repletion of intracellular potassium stores could avoid HlyA induced macrophage cell death. The findings of this study will help to understand the mechanism of α-hemolysin induced inflammatory response and cell death.
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Affiliation(s)
- Vivek Verma
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi (North Campus), Delhi, 110007, India
| | - Parveen Kumar
- Department of Urology, University of Alabama At Birmingham, Hugh Kaul Genetics Building, Birmingham, AL, USA
| | - Surbhi Gupta
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi (North Campus), Delhi, 110007, India
| | - Sonal Yadav
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi (North Campus), Delhi, 110007, India
| | - Rakesh Singh Dhanda
- Stem Cell Laboratory, Longboat Explorers AB, SMiLE Incubator, Scheelevägen 2, Lund, Sweden
| | - Henrik Thorlacius
- Department of Clinical Sciences, Section of Surgery, Malmö, Skåne University Hospital, Lund University, Malmö, Sweden
| | - Manisha Yadav
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi (North Campus), Delhi, 110007, India.
- Department of Clinical Sciences, Section of Surgery, Malmö, Skåne University Hospital, Lund University, Malmö, Sweden.
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Masin J, Osickova A, Jurnecka D, Klimova N, Khaliq H, Sebo P, Osicka R. Retargeting from the CR3 to the LFA-1 receptor uncovers the adenylyl cyclase enzyme-translocating segment of Bordetella adenylate cyclase toxin. J Biol Chem 2020; 295:9349-9365. [PMID: 32393579 DOI: 10.1074/jbc.ra120.013630] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/07/2020] [Indexed: 12/11/2022] Open
Abstract
The Bordetella adenylate cyclase toxin-hemolysin (CyaA) and the α-hemolysin (HlyA) of Escherichia coli belong to the family of cytolytic pore-forming Repeats in ToXin (RTX) cytotoxins. HlyA preferentially binds the αLβ2 integrin LFA-1 (CD11a/CD18) of leukocytes and can promiscuously bind and also permeabilize many other cells. CyaA bears an N-terminal adenylyl cyclase (AC) domain linked to a pore-forming RTX cytolysin (Hly) moiety, binds the complement receptor 3 (CR3, αMβ2, CD11b/CD18, or Mac-1) of myeloid phagocytes, penetrates their plasma membrane, and delivers the AC enzyme into the cytosol. We constructed a set of CyaA/HlyA chimeras and show that the CyaC-acylated segment and the CR3-binding RTX domain of CyaA can be functionally replaced by the HlyC-acylated segment and the much shorter RTX domain of HlyA. Instead of binding CR3, a CyaA1-710/HlyA411-1024 chimera bound the LFA-1 receptor and effectively delivered AC into Jurkat T cells. At high chimera concentrations (25 nm), the interaction with LFA-1 was not required for CyaA1-710/HlyA411-1024 binding to CHO cells. However, interaction with the LFA-1 receptor strongly enhanced the specific capacity of the bound CyaA1-710/HlyA411-1024 chimera to penetrate cells and deliver the AC enzyme into their cytosol. Hence, interaction of the acylated segment and/or the RTX domain of HlyA with LFA-1 promoted a productive membrane interaction of the chimera. These results help delimit residues 400-710 of CyaA as an "AC translocon" sufficient for translocation of the AC polypeptide across the plasma membrane of target cells.
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Affiliation(s)
- Jiri Masin
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Nela Klimova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Humaira Khaliq
- 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
| | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
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Silbergleit M, Vasquez AA, Miller CJ, Sun J, Kato I. Oral and intestinal bacterial exotoxins: Potential linked to carcinogenesis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 171:131-193. [PMID: 32475520 DOI: 10.1016/bs.pmbts.2020.02.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Growing evidence suggests that imbalances in resident microbes (dysbiosis) can promote chronic inflammation, immune-subversion, and production of carcinogenic metabolites, thus leading to neoplasia. Yet, evidence to support a direct link of individual bacteria species to human sporadic cancer is still limited. This chapter focuses on several emerging bacterial toxins that have recently been characterized for their potential oncogenic properties toward human orodigestive cancer and the presence of which in human tissue samples has been documented. These include cytolethal distending toxins produced by various members of gamma and epsilon Proteobacteria, Dentilisin from mammalian oral Treponema, Pasteurella multocida toxin, two Fusobacterial toxins, FadA and Fap2, Bacteroides fragilis toxin, colibactin, cytotoxic necrotizing factors and α-hemolysin from Escherichia coli, and Salmonella enterica AvrA. It was clear that these bacterial toxins have biological activities to induce several hallmarks of cancer. Some toxins directly interact with DNA or chromosomes leading to their breakdowns, causing mutations and genome instability, and others modulate cell proliferation, replication and death and facilitate immune evasion and tumor invasion, prying specific oncogene and tumor suppressor pathways, such as p53 and β-catenin/Wnt. In addition, most bacterial toxins control tumor-promoting inflammation in complex and diverse mechanisms. Despite growing laboratory evidence to support oncogenic potential of selected bacterial toxins, we need more direct evidence from human studies and mechanistic data from physiologically relevant experimental animal models, which can reflect chronic infection in vivo, as well as take bacterial-bacterial interactions among microbiome into consideration.
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Affiliation(s)
| | - Adrian A Vasquez
- Department of Civil and Environmental Engineering, Wayne State University, Healthy Urban Waters, Detroit, MI, United States
| | - Carol J Miller
- Department of Civil and Environmental Engineering, Wayne State University, Healthy Urban Waters, Detroit, MI, United States
| | - Jun Sun
- Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Ikuko Kato
- Department of Oncology, Wayne State University School of Medicine, Detroit, MI, United States; Department of Pathology, Wayne State University School of Medicine, Detroit, MI, United States.
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Ostolaza H, González-Bullón D, Uribe KB, Martín C, Amuategi J, Fernandez-Martínez X. Membrane Permeabilization by Pore-Forming RTX Toxins: What Kind of Lesions Do These Toxins Form? Toxins (Basel) 2019; 11:toxins11060354. [PMID: 31216745 PMCID: PMC6628442 DOI: 10.3390/toxins11060354] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/12/2019] [Accepted: 06/16/2019] [Indexed: 12/22/2022] Open
Abstract
Pore-forming toxins (PFTs) form nanoscale pores across target membranes causing cell death. The pore-forming cytolysins of the RTX (repeats in toxin) family belong to a steadily increasing family of proteins characterized by having in their primary sequences a number of glycine- and aspartate-rich nonapeptide repeats. They are secreted by a variety of Gram-negative bacteria and form ion-permeable pores in several cell types, such as immune cells, epithelial cells, or erythrocytes. Pore-formation by RTX-toxins leads to the dissipation of ionic gradients and membrane potential across the cytoplasmic membrane of target cells, which results in cell death. The pores formed in lipid bilayers by the RTX-toxins share some common properties such as cation selectivity and voltage-dependence. Hemolytic and cytolytic RTX-toxins are important virulence factors in the pathogenesis of the producing bacteria. And hence, understanding the function of these proteins at the molecular level is critical to elucidating their role in disease processes. In this review we summarize the current state of knowledge on pore-formation by RTX toxins, and include recent results from our own laboratory regarding the pore-forming activity of adenylate cyclase toxin (ACT or CyaA), a large protein toxin secreted by Bordetella pertussis, the bacterium causative of whooping cough.
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Affiliation(s)
- Helena Ostolaza
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - David González-Bullón
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Kepa B Uribe
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Cesar Martín
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Jone Amuategi
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Xabier Fernandez-Martínez
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
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Verma V, Gupta S, Kumar P, Rawat A, Singh Dhanda R, Yadav M. Efficient production of endotoxin depleted bioactive α-hemolysin of uropathogenicEscherichia coli. Prep Biochem Biotechnol 2019; 49:616-622. [DOI: 10.1080/10826068.2019.1591993] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Vivek Verma
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Surbhi Gupta
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Parveen Kumar
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Ankita Rawat
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | | | - Manisha Yadav
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
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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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10
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Kovach MA, Singer BH, Newstead MW, Zeng X, Moore TA, White ES, Kunkel SL, Peters-Golden M, Standiford TJ. IL-36γ is secreted in microparticles and exosomes by lung macrophages in response to bacteria and bacterial components. J Leukoc Biol 2016; 100:413-21. [PMID: 26864267 DOI: 10.1189/jlb.4a0315-087r] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 01/22/2016] [Indexed: 11/24/2022] Open
Abstract
Interleukin-36 is a family of novel interleukin-1-like proinflammatory cytokines that are highly expressed in epithelial tissues and several myeloid-derived cell types. Like those of classic interleukin-1 cytokines, the secretion mechanisms of interleukin-36 are not well understood. Interleukin-36γ secretion in dermal epithelial cells requires adenosine 5'-triphosphate, which suggests a nonclassical mechanism of secretion. In this study, murine pulmonary macrophages and human alveolar macrophages were treated with recombinant pathogen-associated molecular patterns (intact bacteria: Klebsiella pneumoniae or Streptococcus pneumoniae). Cell lysates were analyzed for messenger ribonucleic acid by quantitative real-time polymerase chain reaction, and conditioned medium was analyzed for interleukin-36γ by enzyme-linked immunosorbent assay, with or without sonication. In addition, conditioned medium was ultracentrifuged at 25,000 g and 100,000 g, to isolate microparticles and exosomes, respectively, and interleukin-36γ protein was assessed in each fraction by Western blot analysis. Interleukin-36γ mRNA was induced in both murine and human lung macrophages by a variety of pathogen-associated molecular patterns, as well as heat-killed and live Klebsiella pneumoniae and Streptococcus pneumoniae, and induction occurred in a myeloid differentiation response gene 88-dependent manner. Secretion of interleukin-36γ protein was enhanced by adenosine 5'-triphosphate. Furthermore, extracellular interleukin-36γ protein detection was markedly enhanced by sonication to disrupt membrane-bound structures. Interleukin-36γ protein was detected by Western blot in microparticles and exosome fractions isolated by ultracentrifugation. Interleukin-36γ was induced and secreted from lung macrophages in response to Gram-negative and -positive bacterial stimulation. The results suggest that interleukin-36γ is secreted in a non-Golgi-dependent manner by lung macrophages in response to Gram-positive and -negative bacterial challenge.
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Affiliation(s)
- Melissa A Kovach
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine
| | - Benjamin H Singer
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine
| | - Michael W Newstead
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine
| | - Xianying Zeng
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine
| | - Thomas A Moore
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine
| | - Eric S White
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine
| | - Steven L Kunkel
- Department of Pathology, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Marc Peters-Golden
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine
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Strain- and host species-specific inflammasome activation, IL-1β release, and cell death in macrophages infected with uropathogenic Escherichia coli. Mucosal Immunol 2016; 9:124-36. [PMID: 25993444 DOI: 10.1038/mi.2015.44] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 04/07/2015] [Indexed: 02/04/2023]
Abstract
Uropathogenic Escherichia coli (UPEC) is the main etiological agent of urinary tract infections (UTIs). Little is known about interactions between UPEC and the inflammasome, a key innate immune pathway. Here we show that UPEC strains CFT073 and UTI89 trigger inflammasome activation and lytic cell death in human macrophages. Several other UPEC strains, including two multidrug-resistant ST131 isolates, did not kill macrophages. In mouse macrophages, UTI89 triggered cell death only at a high multiplicity of infection, and CFT073-mediated inflammasome responses were completely NLRP3-dependent. Surprisingly, CFT073- and UTI89-mediated responses only partially depended on NLRP3 in human macrophages. In these cells, NLRP3 was required for interleukin-1β (IL-1β) maturation, but contributed only marginally to cell death. Similarly, caspase-1 inhibition did not block cell death in human macrophages. In keeping with such differences, the pore-forming toxin α-hemolysin mediated a substantial proportion of CFT073-triggered IL-1β secretion in mouse but not human macrophages. There was also a more substantial α-hemolysin-independent cell death response in human vs. mouse macrophages. Thus, in mouse macrophages, CFT073-triggered inflammasome responses are completely NLRP3-dependent, and largely α-hemolysin-dependent. In contrast, UPEC activates an NLRP3-independent cell death pathway and an α-hemolysin-independent IL-1β secretion pathway in human macrophages. This has important implications for understanding UTI in humans.
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Hessain AM, Al-Arfaj AA, Zakri AM, El-Jakee JK, Al-Zogibi OG, Hemeg HA, Ibrahim IM. Molecular characterization of Escherichia coli O157:H7 recovered from meat and meat products relevant to human health in Riyadh, Saudi Arabia. Saudi J Biol Sci 2015; 22:725-9. [PMID: 26587000 PMCID: PMC4625360 DOI: 10.1016/j.sjbs.2015.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 05/31/2015] [Accepted: 06/10/2015] [Indexed: 11/17/2022] Open
Abstract
Raw meat can harbor pathogenic bacteria, potentially harmful to humans such as Escherichia coli O157:H7 causing diarrhea and hemolytic-uremic syndrome (HS). Therefore, the current study was carried out to evaluate the prevalence and the molecular detection characterization of E. coli serotype O157:H7 recovered from raw meat and meat products collected from Saudi Arabia. During the period of 25th January 2013 to 25th March 2014, 370 meat samples were collected from abattoirs and markets located in Riyadh, Saudi Arabia "200 raw meat samples and 170 meat products". Bacteriological analysis of the meat samples and serotyping of the isolated E. coli revealed the isolation of 11 (2.97%) strains of E. coli O157:H7. Isolation of E. coli O157:H7 in raw beef, chicken and mutton were 2%, 2.5%, and 2.5%, respectively, however, there was no occurrence in raw turkey. The incidences of E. coli O157:H7 in ground beef, beef burgers, beef sausage, ground chicken and chicken burgers were 5%, 10%, 0.0%, 5% and 0.0%, respectively. The multiplex PCR assay revealed that 3 (27.27%) out of 11 E. coli O157:H7 isolates from raw beef, chicken and mutton had stx1, stx2, and eae while 5 (45.45%) E. coli O157:H7 isolates from ground beef, ground chicken, and raw beef had both stx1 and stx2. However, from beef burgers, only one E. coli O157:H7 isolate had stx1 while two were positive for hlyA gene. These results call for urgent attention toward appropriate controls and good hygienic practices in dealing with raw meat.
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Affiliation(s)
- Ashgan M. Hessain
- Department of Health Science, College of Applied Studies and Community Service, King Saud University, P.O. Box 22459, Riyadh 11495, Saudi Arabia
- Department of Microbiology, Faculty of Veterinary Medicine, Cairo University, P.O. Box 2446, Cairo 14242, Giza, Egypt
| | - Abdullah A. Al-Arfaj
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Adel M. Zakri
- Department of Plant Production, College of Food and Agriculture Science, King Saud University, P.O. Box 2466, Riyadh 11451, Saudi Arabia
| | - Jakeen K. El-Jakee
- Department of Microbiology, Faculty of Veterinary Medicine, Cairo University, P.O. Box 2446, Cairo 14242, Giza, Egypt
| | - Onizan G. Al-Zogibi
- Department of Biology, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, Saudi Arabia
| | - Hassan A. Hemeg
- Department of Medical Technology/Microbiology, College of Applied Medical Science, Taibah University, Madinah, Saudi Arabia
| | - Ihab M. Ibrahim
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
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13
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Benz R. Channel formation by RTX-toxins of pathogenic bacteria: Basis of their biological activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:526-37. [PMID: 26523409 DOI: 10.1016/j.bbamem.2015.10.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/10/2015] [Accepted: 10/28/2015] [Indexed: 12/15/2022]
Abstract
The pore-forming cytolysins of the RTX-toxin (Repeats in ToXin) family are a relatively small fraction of a steadily increasing family of proteins that contain several functionally important glycine-rich and aspartate containing nonapeptide repeats. These cytolysins produced by a variety of Gram-negative bacteria form ion-permeable channels in erythrocytes and other eukaryotic cells. Hemolytic and cytolytic RTX-toxins represent pathogenicity factors of the toxin-producing bacteria and are very often important key factors in pathogenesis of the bacteria. Channel formation by RTX-toxins lead to the dissipation of ionic gradients and membrane potential across the cytoplasmic membrane of target cells, which results in cell death. Here we discuss channel formation and channel properties of some of the best known RTX-toxins, such as α-hemolysin (HlyA) of Escherichia coli and the uropathogenic EHEC strains, the adenylate cyclase toxin (ACT, CyaA) of Bordetella pertussis and the RTX-toxins (ApxI, ApxII and ApxIII) produced by different strains of Actinobacillus pleuropneumoniae. The channels formed by these RTX-toxins in lipid bilayers share some common properties such as cation selectivity and voltage-dependence. Furthermore the channels are transient and show frequent switching between different ion-conducting states. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.
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Affiliation(s)
- Roland Benz
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759, Bremen, 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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15
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Bielaszewska M, Rüter C, Kunsmann L, Greune L, Bauwens A, Zhang W, Kuczius T, Kim KS, Mellmann A, Schmidt MA, Karch H. Enterohemorrhagic Escherichia coli hemolysin employs outer membrane vesicles to target mitochondria and cause endothelial and epithelial apoptosis. PLoS Pathog 2013; 9:e1003797. [PMID: 24348251 PMCID: PMC3861543 DOI: 10.1371/journal.ppat.1003797] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 10/14/2013] [Indexed: 01/08/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) strains cause diarrhea and hemolytic uremic syndrome resulting from toxin-mediated microvascular endothelial injury. EHEC hemolysin (EHEC-Hly), a member of the RTX (repeats-in-toxin) family, is an EHEC virulence factor of increasingly recognized importance. The toxin exists as free EHEC-Hly and as EHEC-Hly associated with outer membrane vesicles (OMVs) released by EHEC during growth. Whereas the free toxin is lytic towards human endothelium, the biological effects of the OMV-associated EHEC-Hly on microvascular endothelial and intestinal epithelial cells, which are the major targets during EHEC infection, are unknown. Using microscopic, biochemical, flow cytometry and functional analyses of human brain microvascular endothelial cells (HBMEC) and Caco-2 cells we demonstrate that OMV-associated EHEC-Hly does not lyse the target cells but triggers their apoptosis. The OMV-associated toxin is internalized by HBMEC and Caco-2 cells via dynamin-dependent endocytosis of OMVs and trafficked with OMVs into endo-lysosomal compartments. Upon endosome acidification and subsequent pH drop, EHEC-Hly is separated from OMVs, escapes from the lysosomes, most probably via its pore-forming activity, and targets mitochondria. This results in decrease of the mitochondrial transmembrane potential and translocation of cytochrome c to the cytosol, indicating EHEC-Hly-mediated permeabilization of the mitochondrial membranes. Subsequent activation of caspase-9 and caspase-3 leads to apoptotic cell death as evidenced by DNA fragmentation and chromatin condensation in the intoxicated cells. The ability of OMV-associated EHEC-Hly to trigger the mitochondrial apoptotic pathway in human microvascular endothelial and intestinal epithelial cells indicates a novel mechanism of EHEC-Hly involvement in the pathogenesis of EHEC diseases. The OMV-mediated intracellular delivery represents a newly recognized mechanism for a bacterial toxin to enter host cells in order to target mitochondria. During the last 30 years, enterohemorrhagic Escherichia coli (EHEC) emerged as worldwide causes of diarrhea and hemolytic uremic syndrome, the most common cause of acute kidney failure in children. EHEC hemolysin (EHEC-Hly) is one of the toxins produced by EHEC during infection that afflict the human host. EHEC-Hly belongs to a large family of toxins, whose members typically kill target cells by inserting themselves into the cell membranes, which results in pore formation and ultimately cell lysis. Here we show that EHEC-Hly associated with outer membrane vesicles (OMVs) secreted by EHEC during growth does not lyse human microvascular endothelial and intestinal epithelial cells, which are the major targets in EHEC-mediated human diseases. Instead, the OMV-associated EHEC-Hly uses the OMVs to enter the cells and acts intracellularly. The toxin separates from its carriers in lysosomes, translocates into mitochondria and triggers apoptotic death of the target cells via the mitochondrial pathway. EHEC-Hly is the first known bacterial toxin, which enters host cells via OMVs in order to attack mitochondria. The apoptotic potential of OMV-associated EHEC-Hly indicates a novel mechanism for this toxin to cause cell death during human EHEC infections.
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Affiliation(s)
| | - Christian Rüter
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
| | - Lisa Kunsmann
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Lilo Greune
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
| | - Andreas Bauwens
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Wenlan Zhang
- Institute of Hygiene, University of Münster, Münster, Germany
| | | | - Kwang Sik Kim
- Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | | | - M. Alexander Schmidt
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
| | - Helge Karch
- Institute of Hygiene, University of Münster, Münster, Germany
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16
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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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Wiles TJ, Mulvey MA. The RTX pore-forming toxin α-hemolysin of uropathogenic Escherichia coli: progress and perspectives. Future Microbiol 2013; 8:73-84. [PMID: 23252494 DOI: 10.2217/fmb.12.131] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Members of the RTX family of protein toxins are functionally conserved among an assortment of bacterial pathogens. By disrupting host cell integrity through their pore-forming and cytolytic activities, this class of toxins allows pathogens to effectively tamper with normal host cell processes, promoting pathogenesis. Here, we focus on the biology of RTX toxins by describing salient properties of a prototype member, α-hemolysin, which is often encoded by strains of uropathogenic Escherichia coli. It has long been appreciated that RTX toxins can have distinct effects on host cells aside from outright lysis. Recently, advances in modeling and analysis of host-pathogen interactions have led to novel findings concerning the consequences of pore formation during host-pathogen interactions. We discuss current progress on longstanding questions concerning cell specificity and pore formation, new areas of investigation that involve toxin-mediated perturbations of host cell signaling cascades and perspectives on the future of RTX toxin investigation.
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Affiliation(s)
- Travis J Wiles
- Division of Microbiology & Immunology, Pathology Department, University of Utah, 15 North Medical Drive East #2100, Salt Lake City, UT 84112-0565, USA
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18
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Bacteria differentially induce degradation of Bcl-xL, a survival protein, by human platelets. Blood 2012; 120:5014-20. [PMID: 23086749 DOI: 10.1182/blood-2012-04-420661] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Bacteria can enter the bloodstream in response to infectious insults. Bacteremia elicits several immune and clinical complications, including thrombocytopenia. A primary cause of thrombocytopenia is shortened survival of platelets. We demonstrate that pathogenic bacteria induce apoptotic events in platelets that include calpain-mediated degradation of Bcl-x(L), an essential regulator of platelet survival. Specifically, bloodstream bacterial isolates from patients with sepsis induce lateral condensation of actin, impair mitochondrial membrane potential, and degrade Bcl-x(L) protein in platelets. Bcl-x(L) protein degradation is enhanced when platelets are exposed to pathogenic Escherichia coli that produce the pore-forming toxin α-hemolysin, a response that is markedly attenuated when the gene is deleted from E coli. We also found that nonpathogenic E coli gain degrading activity when they are forced to express α-hemolysin. Like α-hemolysin, purified α-toxin readily degrades Bcl-x(L) protein in platelets, as do clinical Staphylococcus aureus isolates that produce α-toxin. Inhibition of calpain activity, but not the proteasome, rescues Bcl-x(L) protein degradation in platelets coincubated with pathogenic E coli including α-hemolysin producing strains. This is the first evidence that pathogenic bacteria can trigger activation of the platelet intrinsic apoptosis program and our results suggest a new mechanism by which bacterial pathogens might cause thrombocytopenia in patients with bloodstream infections.
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19
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Linhartová I, Bumba L, Mašín J, Basler M, Osička R, Kamanová J, Procházková K, Adkins I, Hejnová-Holubová J, Sadílková L, Morová J, Sebo P. RTX proteins: a highly diverse family secreted by a common mechanism. FEMS Microbiol Rev 2011; 34:1076-112. [PMID: 20528947 PMCID: PMC3034196 DOI: 10.1111/j.1574-6976.2010.00231.x] [Citation(s) in RCA: 360] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Repeats-in-toxin (RTX) exoproteins of Gram-negative bacteria form a steadily growing family of proteins with diverse biological functions. Their common feature is the unique mode of export across the bacterial envelope via the type I secretion system and the characteristic, typically nonapeptide, glycine- and aspartate-rich repeats binding Ca2+ ions. In this review, we summarize the current state of knowledge on the organization of rtx loci and on the biological and biochemical activities of therein encoded proteins. Applying several types of bioinformatic screens on the steadily growing set of sequenced bacterial genomes, over 1000 RTX family members were detected, with the biological functions of most of them remaining to be characterized. Activities of the so far characterized RTX family members are then discussed and classified according to functional categories, ranging from the historically first characterized pore-forming RTX leukotoxins, through the large multifunctional enzymatic toxins, bacteriocins, nodulation proteins, surface layer proteins, up to secreted hydrolytic enzymes exhibiting metalloprotease or lipase activities of industrial interest.
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Affiliation(s)
- Irena Linhartová
- Institute of Microbiology AS CR v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic
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20
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Lin CF, Chen CL, Huang WC, Cheng YL, Hsieh CY, Wang CY, Hong MY. Different types of cell death induced by enterotoxins. Toxins (Basel) 2010; 2:2158-76. [PMID: 22069678 PMCID: PMC3153280 DOI: 10.3390/toxins2082158] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 08/03/2010] [Indexed: 02/07/2023] Open
Abstract
The infection of bacterial organisms generally causes cell death to facilitate microbial invasion and immune escape, both of which are involved in the pathogenesis of infectious diseases. In addition to the intercellular infectious processes, pathogen-produced/secreted enterotoxins (mostly exotoxins) are the major weapons that kill host cells and cause diseases by inducing different types of cell death, particularly apoptosis and necrosis. Blocking these enterotoxins with synthetic drugs and vaccines is important for treating patients with infectious diseases. Studies of enterotoxin-induced apoptotic and necrotic mechanisms have helped us to create efficient strategies to use against these well-characterized cytopathic toxins. In this article, we review the induction of the different types of cell death from various bacterial enterotoxins, such as staphylococcal enterotoxin B, staphylococcal alpha-toxin, Panton-Valentine leukocidin, alpha-hemolysin of Escherichia coli, Shiga toxins, cytotoxic necrotizing factor 1, heat-labile enterotoxins, and the cholera toxin, Vibrio cholerae. In addition, necrosis caused by pore-forming toxins, apoptotic signaling through cross-talk pathways involving mitochondrial damage, endoplasmic reticulum stress, and lysosomal injury is discussed.
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Affiliation(s)
- Chiou-Feng Lin
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; (W.-C.H.); (Y.-L.C.); (C.-Y.H.); (C.-Y.W.); (M.-Y.H.)
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; (C.-L.C.)
- Author to whom correspondence should be addressed; ; Tel.: +886-06-235-3535 ext. 4240; Fax: +886-06-275-8781
| | - Chia-Ling Chen
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; (C.-L.C.)
| | - Wei-Ching Huang
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; (W.-C.H.); (Y.-L.C.); (C.-Y.H.); (C.-Y.W.); (M.-Y.H.)
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Yi-Lin Cheng
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; (W.-C.H.); (Y.-L.C.); (C.-Y.H.); (C.-Y.W.); (M.-Y.H.)
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Chia-Yuan Hsieh
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; (W.-C.H.); (Y.-L.C.); (C.-Y.H.); (C.-Y.W.); (M.-Y.H.)
| | - Chi-Yun Wang
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; (W.-C.H.); (Y.-L.C.); (C.-Y.H.); (C.-Y.W.); (M.-Y.H.)
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Ming-Yuan Hong
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; (W.-C.H.); (Y.-L.C.); (C.-Y.H.); (C.-Y.W.); (M.-Y.H.)
- Department of Emergency, National Cheng Kung University Hospital, Tainan 701, Taiwan
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Martin U, Scholler J, Gurgel J, Renshaw B, Sims JE, Gabel CA. Externalization of the leaderless cytokine IL-1F6 occurs in response to lipopolysaccharide/ATP activation of transduced bone marrow macrophages. THE JOURNAL OF IMMUNOLOGY 2009; 183:4021-30. [PMID: 19717513 DOI: 10.4049/jimmunol.0803301] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
An interesting trait shared by many members of the IL-1 cytokine family is the absence of a signal sequence that can direct the newly synthesized polypeptides to the endoplasmic reticulum. As a result, these cytokines accumulate intracellularly. Recent studies investigating IL-1beta export established that its release is facilitated via activation of an intracellular multiprotein complex termed the inflammasome. The purpose of the current study was to explore the mechanism by which murine IL-1F6 is released from bone marrow-derived macrophages (BMDMs) and to compare this mechanism to that used by IL-1beta. BMDMs were engineered to overexpress IL-1F6 by retroviral transduction; cells overexpressing GFP also were generated to provide a noncytokine comparator. The transduced cells constitutively expressed IL-1F6 and GFP, but they did not constitutively release these polypeptides to the medium. Enhanced release of IL-1F6 was achieved by treating with LPS followed by ATP-induced activation of the P2X(7) receptor; GFP also was released under these conditions. No obvious proteolytic cleavage of IL-1F6 was noted following P2X(7) receptor-induced release. Stimulus-induced release of IL-1F6 and GFP demonstrated comparable susceptibility to pharmacological modulation. Therefore, transduced IL-1F6 is released in parallel with endogenous mature IL-1beta from LPS/ATP-treated BMDMs, but this externalization process is not selective for cytokines as a noncytokine (GFP) shows similar behavior. These findings suggest that IL-1F6 can be externalized via a stimulus-coupled mechanism comparable to that used by IL-1beta, and they provide additional insight into the complex cellular processes controlling posttranslational processing of the IL-1 cytokine family.
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Affiliation(s)
- Unja Martin
- Department of Inflammation, Amgen, Seattle, WA 98119, USA
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22
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Alpha-hemolysin from Escherichia coli uses endogenous amplification through P2X receptor activation to induce hemolysis. Proc Natl Acad Sci U S A 2009; 106:4030-5. [PMID: 19225107 DOI: 10.1073/pnas.0807044106] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Escherichia coli is the dominant facultative bacterium in the normal intestinal flora. E. coli is, however, also responsible for the majority of serious extraintestinal infections. There are distinct serotypical differences between facultative and invasive E. coli strains. Invasive strains frequently produce virulence factors such as alpha-hemolysin (HlyA), which causes hemolysis by forming pores in the erythrocyte membrane. The present study reveals that this pore formation triggers purinergic receptor activation to mediate the full hemolytic action. Non-selective ATP-receptor (P2) antagonists (PPADS, suramin) and ATP scavengers (apyrase, hexokinase) concentration dependently inhibited HlyA-induced lysis of equine, murine, and human erythrocytes. The pattern of responsiveness to more selective P2-antagonists implies that both P2X(1) and P2X(7) receptors are involved in HlyA-induced hemolysis in all three species. In addition, our results also propose a role for the pore protein pannexin1 in HlyA-induced hemolysis, as non-selective inhibitors of this channel significantly reduced hemolysis in the three species. In conclusion, activation of P2X receptors and possibly also pannexins augment hemolysis induced by the bacterial toxin, HlyA. These findings potentially have clinical perspectives as P2 antagonists may ameliorate symptoms during sepsis with hemolytic bacteria.
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23
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Gabel CA. P2 purinergic receptor modulation of cytokine production. Purinergic Signal 2007; 3:27-38. [PMID: 18404416 PMCID: PMC2096759 DOI: 10.1007/s11302-006-9034-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Accepted: 01/10/2006] [Indexed: 11/24/2022] Open
Abstract
Cytokines serve important functions in controlling host immunity. Cells involved in the synthesis of these polypeptide mediators have evolved highly regulated processes to ensure that production is carefully balanced. In inflammatory and immune disorders, however, mis-regulation of the production and/or activity of cytokines is recognized as a major contributor to the disease process, and therapeutics that target individual cytokines are providing very effective treatment options in the clinic. Leukocytes are the principle producers of a number of key cytokines, and these cells also express numerous members of the purinergic P2 receptor family. Studies in several cellular systems have provided evidence that P2 receptor modulation can affect cytokine production, and mechanistic features of this regulation have emerged. This review highlights three separate examples corresponding to (1) P2Y₆ receptor mediated impact on interleukin (IL)-8 production, (2) P2Y₁₁ receptor-mediated affects on IL-12/23 output, and (3) P2X₇ receptor mediated IL-1β posttranslational processing. These examples demonstrate important roles of purinergic receptors in the modulation of cytokine production. Extension of these cellular observations to in vivo situations may lead to new therapeutic strategies for treating cytokine-mediated diseases.
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Affiliation(s)
- Christopher A Gabel
- Department of Inflammation, Amgen, Inc., 1201 Amgen Court West, Seattle, WA, 98119, USA,
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24
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Sheshko V, Hejnova J, Rehakova Z, Sinkora J, Faldyna M, Alexa P, Felsberg J, Nemcova R, Bomba A, Sebo P. HlyA knock out yields a saferEscherichia coliA0 34/86 variant with unaffected colonization capacity in piglets. ACTA ACUST UNITED AC 2006; 48:257-66. [PMID: 17064280 DOI: 10.1111/j.1574-695x.2006.00140.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Escherichia coli A0 34/86 (O83:K24:H31) has been successfully used for prophylactic and therapeutic intestinal colonization of premature and newborn infants, with the aim of preventing nosocomial infections. Although E. coli A0 34/86 was described as a nonpathogenic commensal, partial sequencing revealed that its genome harbours gene clusters highly homologous to virulence determinants of different types of E. coli, including closely linked genes of the alpha-haemolysin operon (hlyCABD) and for the cytotoxic necrotizing factor (cnf1). A haemolysin-deficient mutant (Delta hlyA) of E. coli A0 34/86 was generated and its colonization capacity was determined. The results show that a single dose of the A0 34/86 wild-type or Delta hlyA strains resulted in efficient intestinal colonization of newborn conventional piglets, and that this was still considerable after several weeks. No difference was observed between the wild-type and the mutant strains, showing that haemolysin expression does not contribute to intestinal colonization capacity of E. coli A0 34/86. Safety experiments revealed that survival of colostrum-deprived gnotobiotic newborn piglets was substantially higher upon colonization by the nonhaemolytic strain than following inoculation by its wild-type ancestor. We suggest that the E. coli A0 34/86 Delta hlyA mutant may represent a safer prophylactic and/or immunomodulatory tool with unaffected colonization capacity.
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Affiliation(s)
- Valeria Sheshko
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Donohue M, Chung Y, Magnuson ML, Ward M, Selgrade MJ, Vesper S. Hemolysin chrysolysin from Penicillium chrysogenum promotes inflammatory response. Int J Hyg Environ Health 2005; 208:279-85. [PMID: 16078642 DOI: 10.1016/j.ijheh.2005.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Some strains of Penicillium chrysogenum produce a proteinaceous hemolysin, chrysolysinTM, when incubated on sheep's blood agar at 37 degrees C but not at 23 degrees C. However, 92% (11/12) of the indoor air isolates produced hemolysis but only 43% (3/7) of the non-indoor air isolates did so. Chrysolysin is an aggregating protein composed of approximately 2kDa monomers, contains one cysteine amino acid, and has an isoelectric point of 4.85. Treatment of murine macrophage cell line RAW 264.7 with purified chrysolysin caused statistically significant (T-test, p < 0.05) increased production of macrophage inflammatory protein-2 (MIP-2) in a dose dependent manner after 6 h treatment. This suggests that chrysolysin might act to promote the host's inflammatory response after P. chrysogenum exposures.
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Affiliation(s)
- Maura Donohue
- National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, OH, USA
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26
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Kerényi M, Allison HE, Bátai I, Sonnevend A, Emödy L, Plaveczky N, Pál T. Occurrence of hlyA and sheA genes in extraintestinal Escherichia coli strains. J Clin Microbiol 2005; 43:2965-8. [PMID: 15956433 PMCID: PMC1151894 DOI: 10.1128/jcm.43.6.2965-2968.2005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The association of a hemolytic phenotype with the carriage of the alpha-hemolysin gene (hlyA) and/or the silent hemolysin gene (sheA or clyA) among 540 extraintestinal clinical isolates of Escherichia coli and 110 fecal isolates from healthy individuals was investigated. Though HlyA is an important virulence factor in extraintestinal E. coli infection, the role of SheA is not completely clarified. Two hemolytic sheA+ E. coli strains that lacked hlyA and possessed no other hemolysin genes were identified. No hlyA+ sheA+ strains were identified, suggesting that there is possible incompatibility between hlyA and sheA in the chromosome of E. coli.
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Affiliation(s)
- Monika Kerényi
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Szigeti u. 12. H-7624, Hungary.
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27
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Vesper SJ, Vesper MJ. Possible role of fungal hemolysins in sick building syndrome. ADVANCES IN APPLIED MICROBIOLOGY 2004; 55:191-213. [PMID: 15350795 DOI: 10.1016/s0065-2164(04)55007-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Stephen J Vesper
- U.S. Environmental Protection Agency Office of Research and Development, National Exposure Research Laboratory 26 W. M. L. King Drive Cincinnati, Ohio 45268, USA
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28
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Verhoef PA, Kertesy SB, Estacion M, Schilling WP, Dubyak GR. Maitotoxin Induces Biphasic Interleukin-1β Secretion and Membrane Blebbing in Murine Macrophages. Mol Pharmacol 2004. [DOI: 10.1124/mol.66.4.909] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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29
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Sluyter R, Shemon AN, Wiley JS. Glu496 to Ala polymorphism in the P2X7 receptor impairs ATP-induced IL-1 beta release from human monocytes. THE JOURNAL OF IMMUNOLOGY 2004; 172:3399-405. [PMID: 15004138 DOI: 10.4049/jimmunol.172.6.3399] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Priming of monocytes with LPS produces large quantities of intracellular, biologically inactive IL-1beta that can be processed and released by subsequent activation of the P2X7 receptor by extracellular ATP. We examined whether a loss-of-function polymorphism of the human P2X7 receptor (Glu496Ala) impairs this process. Both ATP-induced ethidium+ uptake and ATP-induced shedding of L-selectin (CD62L) were nearly absent in monocytes from four subjects homozygous for Glu496Ala confirming that this polymorphism impairs P2X7 function. The level of ATP-induced IL-1beta released in 2 h from LPS-activated whole blood from homozygous subjects was 50% of that from wild-type samples. A more marked defect in IL-1beta release was observed from LPS-activated monocytes of homozygous subjects which was only 22% of that released from wild-type monocytes after a 30-min incubation with ATP. However, after a 60-min incubation with ATP, the amount of IL-1beta released from homozygous monocytes was 70% of that released from wild-type monocytes. Incubation of monocytes of either genotype with nigericin resulted in a similar release of IL-1beta. Western blotting demonstrated that ATP induced the release of mature 17-kDa IL-1beta from monocytes, and confirmed that this process was impaired in homozygous monocytes. Finally, ATP-induced 86Rb+ efflux was 9-fold lower from homozygous monocytes than from wild-type monocytes. The results indicate that ATP-induced release of IL-1beta is slower in monocytes from subjects homozygous for the Glu496Ala polymorphism in the P2X7 receptor and that this reduced rate of IL-1beta release is associated with a lower ATP-induced K+ efflux.
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Affiliation(s)
- Ronald Sluyter
- Department of Medicine, University of Sydney at Nepean Hospital, Penrith, New South Wales, Australia.
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30
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Leite F, Kuckleburg C, Atapattu D, Schultz R, Czuprynski CJ. BHV-1 infection and inflammatory cytokines amplify the interaction of Mannheimia haemolytica leukotoxin with bovine peripheral blood mononuclear cells in vitro. Vet Immunol Immunopathol 2004; 99:193-202. [PMID: 15135985 DOI: 10.1016/j.vetimm.2004.02.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2003] [Revised: 12/22/2003] [Accepted: 02/09/2004] [Indexed: 10/26/2022]
Abstract
Bovine herpesvirus-1 (BHV-1) has been reported to increase the susceptibility of cattle to respiratory disease caused by Mannheimia (Pasteurella) haemolytica A1. The principal virulence factor of M. haemolytica is a leukotoxin (LKT) that can specifically kill ruminant leukocytes following its binding to the beta2-integrin CD11a/CD18 (lymphocyte function-associated antigen 1 (LFA-1)). In this study, we investigated the effects of experimental infection of bovine peripheral blood mononuclear cells (MNCs) with BHV-1 in vitro, on the subsequent interaction of these cells with the M. haemolytica LKT. We found that BHV-1 infection increased LFA-1 expression (as assessed by flow cytometry), and subsequently enhanced LKT binding and cytotoxicity to bovine MNCs. We also found that BHV-1 infection increased CD18, IL-1beta, and IFN-gamma mRNA expression by MNCs. As previously reported for bovine polymorphonuclear neutrophils (PMNs), MNCs increased their expression of LFA-1, and their LKT binding and cytotoxicity, following exposure to IL-1beta, TNF-alpha, and IFN-gamma. These findings suggest that BHV-1 infection, and the resulting release of inflammatory cytokines, can stimulate expression of LFA-1 in bovine MNCs, thus enhancing the binding and biological effects of LKT. If such a mechanism occurs in vivo it might explain, in part, the increased susceptibility of BHV-1 infected cattle to bovine pasteurellosis.
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Affiliation(s)
- F Leite
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
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31
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Suttorp N, Ehreiser P, Hippenstiel S, Fuhrmann M, Krüll M, Tenor H, Schudt C. Hyperpermeability of pulmonary endothelial monolayer: protective role of phosphodiesterase isoenzymes 3 and 4. Lung 2004; 174:181-94. [PMID: 8830194 DOI: 10.1007/bf00173310] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The regulation of endothelial permeability is poorly understood. An increase in endothelial permeability in the pulmonary microvasculature, however, is critical in noncardiogenic pulmonary edema and other diffuse inflammatory reactions. In the present study thrombin and Escherichia coli hemolysin (HlyA), a membrane-perturbing bacterial exotoxin, were used to alter hydraulic permeability of porcine pulmonary artery and human endothelial cell monolayers. We also investigated the pharmacological approach of adenylyl cyclase activation/phosphodiesterase (PDE) inhibition to block endothelial hyperpermeability. Thrombin (1-5 units/ml) and HlyA (0.5-3 hemolytic units/ml) dose and time dependently (> 15 min) increased endothelial permeability. Forskolin, cholera toxin, and prostaglandin E1, which all stimulate adenylyl cyclase activity, abrogated this effect. One mM dibutyryl cAMP, a cell membrane-permeable cAMP analogue, was similarly active. Endothelial hyperpermeability was also reduced dose dependently by inhibitors of different PDE isoenzymes (motapizone, rolipram, and zardaverine, which block PDE3 and/or PDE4). The effectiveness of PDE inhibitors was increased in the presence of adenylyl cyclase activators. Analysis of cyclic nucleotide hydrolyzing PDE activity in lysates of human umbilical vein endothelial cells showed high activities of PDE isoenzymes 2, 3, and 4. Consistent with the functional data PDE3 and PDE4 were the major cAMP hydrolysis enzymes in intact endothelial cells. We conclude that the hyperpermeability of pulmonary endothelial monolayers, evoked by thrombin or HlyA, can be blocked by the simultaneous activation of adenylyl cyclase and inhibition of PDEs, especially of PDE3 and PDE4. The demonstration of PDE isoenzymes 2-4 in human endothelial cells will help optimize this therapeutic approach.
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Affiliation(s)
- N Suttorp
- Department of Internal Medicine, Justus Liebig-University of Giessen, Germany
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32
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Stassen M, Müller C, Richter C, Neudörfl C, Hültner L, Bhakdi S, Walev I, Schmitt E. The streptococcal exotoxin streptolysin O activates mast cells to produce tumor necrosis factor alpha by p38 mitogen-activated protein kinase- and protein kinase C-dependent pathways. Infect Immun 2003; 71:6171-7. [PMID: 14573633 PMCID: PMC219607 DOI: 10.1128/iai.71.11.6171-6177.2003] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptolysin O (SLO), a major virulence factor of pyogenic streptococci, binds to cholesterol in the membranes of eukaryotic cells and oligomerizes to form large transmembrane pores. While high toxin doses are rapidly cytocidal, low doses are tolerated because a limited number of lesions can be resealed. Here, we report that at sublethal doses, SLO activates primary murine bone marrow-derived mast cells to degranulate and to rapidly induce or enhance the production of several cytokine mRNAs, including tumor necrosis factor alpha (TNF-alpha). Mast cell-derived TNF-alpha plays an important protective role in murine models of acute inflammation, and the production of this cytokine was analyzed in more detail. Release of biologically active TNF-alpha peaked approximately 4 h after stimulation with SLO. Production of TNF-alpha was blunted upon depletion of protein kinase C by pretreatment of the cells with phorbol-12 myristate-13 acetate. Transient permeabilization of mast cells with SLO also led to the activation of the stress-activated protein kinases p38 mitogen-activated protein (MAP) kinase and c-jun N-terminal kinase (JNK), and inhibition of p38 MAP kinase markedly reduced production of TNF-alpha. In contrast, secretion of preformed granule constituents triggered by membrane permeabilization was not dependent on p38 MAP kinase or on protein kinase C. Thus, transcriptional activation of mast cells following transient permeabilization might contribute to host defense against infections via the beneficial effects of TNF-alpha. However, hyperstimulation of mast cells might also lead to overproduction of TNF-alpha, which would then promote the development of toxic streptococcal syndromes.
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Affiliation(s)
- Michael Stassen
- Institute of Immunology. Institute of Medical Microbiology, Johannes Gutenberg University, Mainz, Germany
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33
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Figueirêdo PMS, Catani CF, Yano T. Serum high-density lipoprotein (HDL) inhibits in vitro enterohemolysin (EHly) activity produced by enteropathogenic Escherichia coli. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2003; 38:53-7. [PMID: 12900055 DOI: 10.1016/s0928-8244(03)00125-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Enterohemolysin (EHly) produced by Escherichia coli shows hemolytic activity towards washed erythrocytes from different animal species on blood agar plates. It has been shown recently that EHly activity is inhibited by normal mammalian serum and by cholesterol in vitro. Plasma lipoproteins can interact with bacterial toxins, such as endotoxin, to reduce their toxicity. In this work, we examine the ability of human purified chylomicrons, very low-density lipoproteins, intermediate-density, low-density and high-density lipoproteins, to inhibit the hemolytic activity of EHly. Our results show that these lipoproteins are hemolysin inactivators, and that high-density lipoprotein is the most potent inhibitor of enterohemolytic activity.
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Affiliation(s)
- Patricia M S Figueirêdo
- Departamento de Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas, P.O. Box 6109, 13081-970, Campinas SP, Brazil
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34
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Leite F, Gyles S, Atapattu D, Maheswaran SK, Czuprynski CJ. Prior exposure to Mannheimia haemolytica leukotoxin or LPS enhances beta(2)-integrin expression by bovine neutrophils and augments LKT cytotoxicity. Microb Pathog 2003; 34:267-75. [PMID: 12782479 DOI: 10.1016/s0882-4010(03)00060-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mannheimia (Pasteurella) haemolytica serotype1 produces a variety of virulence factors that play an important role during the pathogenesis of bovine pneumonic pasteurellosis. Among these, a leukotoxin (LKT) and lipopolysaccharide (LPS) are thought to be the primary virulence factors that contribute to the characteristic pathology of pasteurellosis. Recent evidence suggests that M. haemolytica LKT binding to bovine leukocytes is mediated by the beta(2)-integrin CD11a/CD18 (LFA-1), which subsequently induces activation and death of these cells. Exposure of bovine peripheral blood neutrophils (PMNs) to LKT or LPS induces expression of inflammatory cytokines, which in turn can increase LFA-1 expression and conformational activation. In this study we demonstrated, by flow cytometry and Western blot, that bovine PMNs increased their LFA-1 expression following in vitro exposure to M. haemolytica LKT and LPS. Increased LFA-1 expression by PMNs exposed to LKT and LPS was associated with increased LKT binding and cell death. The results of this study suggest that M. haemolytica LKT and LPS might cooperatively increase LFA-1 expression, and by so doing amplify the lung inflammation that characterizes bovine pasteurellosis.
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Affiliation(s)
- F Leite
- Department of Pathological Sciences, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Drive West, Madison, WI 53705, USA
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35
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Laliberte RE, Perregaux DG, Hoth LR, Rosner PJ, Jordan CK, Peese KM, Eggler JF, Dombroski MA, Geoghegan KF, Gabel CA. Glutathione s-transferase omega 1-1 is a target of cytokine release inhibitory drugs and may be responsible for their effect on interleukin-1beta posttranslational processing. J Biol Chem 2003; 278:16567-78. [PMID: 12624100 DOI: 10.1074/jbc.m211596200] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Stimulus-induced posttranslational processing of human monocyte interleukin-1beta (IL-1beta) is accompanied by major changes to the intracellular ionic environment, activation of caspase-1, and cell death. Certain diarylsulfonylureas inhibit this response, and are designated cytokine release inhibitory drugs (CRIDs). CRIDs arrest activated monocytes so that caspase-1 remains inactive and plasma membrane latency is preserved. Affinity labeling with [(14)C]CRIDs and affinity chromatography on immobilized CRID were used in seeking potential protein targets of their action. Following treatment of intact human monocytes with an epoxide-bearing [(14)C]CRID, glutathione S-transferase (GST) Omega 1-1 was identified as a preferred target. Moreover, labeling of this polypeptide correlated with irreversible inhibition of ATP-induced IL-1beta posttranslational processing. When extracts of human monocytic cells were chromatographed on a CRID affinity column, GST Omega 1-1 bound selectively to the affinity matrix and was eluted by soluble CRID. Recombinant GST Omega 1-1 readily incorporated [(14)C]CRID epoxides, but labeling was negated by co-incubation with S-substituted glutathiones or by mutagenesis of the catalytic center Cys(32) to alanine. Peptide mapping by high performance liquid chromatography-mass spectrometry also demonstrated that Cys(32) was the site of modification. Although S-alkylglutathiones did not arrest ATP-induced IL-1beta posttranslational processing or inhibit [(14)C]CRID incorporation into cell-associated GST Omega 1-1, a glutathione-CRID adduct effectively demonstrated these attributes. Therefore, the ability of CRIDs to arrest stimulus-induced IL-1beta posttranslational processing may be attributable to their interaction with GST Omega 1-1.
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Affiliation(s)
- Ronald E Laliberte
- Department of Antibacterials, Pfizer Global Research and Development, Pfizer, Inc., Groton, Connecticut 06340, USA
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36
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Ohara T, Kojio S, Taneike I, Nakagawa S, Gondaira F, Tamura Y, Gejyo F, Zhang HM, Yamamoto T. Effects of azithromycin on shiga toxin production by Escherichia coli and subsequent host inflammatory response. Antimicrob Agents Chemother 2002; 46:3478-83. [PMID: 12384353 PMCID: PMC128727 DOI: 10.1128/aac.46.11.3478-3483.2002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) colonizes the human intestinal mucosa, produces Stx from phage, and causes the development of hemolytic-uremic syndrome via Stx-induced inflammatory cytokine production. Azithromycin exhibited strong in vitro activity against STEC without inducing Stx-converting phage, in marked contrast to norfloxacin. Azithromycin decreased the tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-6 production from Stx-treated human peripheral mononuclear cells or monocytes to a greater extent than did clarithromycin. In Stx-injected mice, azithromycin significantly suppressed Stx-induced TNF-alpha, IL-1beta, and IL-6 levels in serum and improved the outcome as assessed by survival rate. In the STEC oral infection experiment using immature mice immediately after weaning (weaned immature-mouse model), all mice died within 7 days postinfection. Azithromycin administration gave the mice 100% protection from killing, while ciprofloxacin administration gave them 67% protection. The data suggest that azithromycin (at least at higher concentrations) has a strong effect on Stx production by STEC and on the Stx-induced inflammatory host response and prevents death in mice. Azithromycin may have a beneficial effect on STEC-associated disease.
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Affiliation(s)
- Tatsuki Ohara
- Division of Bacteriology, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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37
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Houdouin V, Bonacorsi S, Brahimi N, Clermont O, Nassif X, Bingen E. A uropathogenicity island contributes to the pathogenicity of Escherichia coli strains that cause neonatal meningitis. Infect Immun 2002; 70:5865-9. [PMID: 12228319 PMCID: PMC128312 DOI: 10.1128/iai.70.10.5865-5869.2002] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report that the archetypal Escherichia coli strain C5 causing neonatal meningitis harbors a pathogenicity island (PAI) designated PAI I(C5) that is similar to the PAI II(J96) of uropathogenic E. coli J96 inserted in the leuX-tRNA gene. PAI-negative C5 mutants had a lower capacity than C5 to induce high-level bacteremia in a neonatal rat model. However, no change in their resistance to the bactericidal effect of serum and their capacity to cross the blood-brain barrier was observed.
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Affiliation(s)
- Véronique Houdouin
- Laboratoire d'Etudes de Génétique Bactérienne dans les Infections de l'Enfant (EA 3105), Université Denis Diderot-Paris 7, Hôpital Robert Debré, 75019 Paris, France
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38
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Taneike I, Zhang HM, Wakisaka-Saito N, Yamamoto T. Enterohemolysin operon of Shiga toxin-producing Escherichia coli: a virulence function of inflammatory cytokine production from human monocytes. FEBS Lett 2002; 524:219-24. [PMID: 12135770 DOI: 10.1016/s0014-5793(02)03027-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Shiga toxin-producing Escherichia coli (STEC) is associated with hemolytic uremic syndrome (HUS). Although most clinical isolates of STEC produce hemolysin (called enterohemolysin), the precise role of enterohemolysin in the pathogenesis of STEC infections is unknown. Here we demonstrated that E. coli carrying the cloned enterohemolysin operon (hlyC, A, B, D genes) from an STEC human strain induced the production of interleukin-1beta (IL-1beta) through its mRNA expression but not tumor necrosis factor-alpha from human monocytes. No IL-1beta release was observed with an enterohemolysin (HlyA)-negative, isogenic E. coli strain carrying a mutation in the hlyA gene. The data suggest that enterohemolysin, a pore-forming toxin, induces the production of IL-1beta, which is one of serum risk markers for HUS.
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Affiliation(s)
- Ikue Taneike
- Division of Bacteriology, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 757 Ichibanchou, Asahimachidori, Niigata, Japan
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39
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Cirillo SLG, Yan L, Littman M, Samrakandi MM, Cirillo JD. Role of the Legionella pneumophila rtxA gene in amoebae. MICROBIOLOGY (READING, ENGLAND) 2002; 148:1667-1677. [PMID: 12055287 DOI: 10.1099/00221287-148-6-1667] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Legionella pneumophila infects humans, causing Legionnaires' disease, from aerosols generated by domestic and environmental water sources. In aquatic environments L. pneumophila is thought to replicate primarily in protozoa. A 'repeats in structural toxin' (RTX) gene, rtxA, from L. pneumophila was identified recently that plays a role in entry and replication in human macrophages and also has the ability to infect mice. However, the role of this gene in the interaction of L. pneumophila with environmental protozoa and its distribution in different Legionella species has not been examined. Southern analyses demonstrated that rtxA is present in all L. pneumophila isolates tested and correlates with species that have been shown to cause disease in humans. To evaluate the importance of rtxA in the interaction with protozoa a series of studies was carried out in an environmental host for L. pneumophila, Acanthamoeba castellanii. The L. pneumophila rtxA gene plays a role in both adherence and entry into A. castellanii similar to that observed in human monocytic cells. Furthermore, it was found that rtxA is involved in intracellular survival and trafficking. In addition to demonstrating involvement of rtxA in the interaction of L. pneumophila with host cells, these data support a role for this gene both during disease in humans and in environmental reservoirs.
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Affiliation(s)
- Suat L G Cirillo
- Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln, 203 VBS, Fair and East Campus Loop, Lincoln, NE 68583, USA1
| | - Ling Yan
- Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln, 203 VBS, Fair and East Campus Loop, Lincoln, NE 68583, USA1
| | - Michael Littman
- Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln, 203 VBS, Fair and East Campus Loop, Lincoln, NE 68583, USA1
| | - Mustapha M Samrakandi
- Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln, 203 VBS, Fair and East Campus Loop, Lincoln, NE 68583, USA1
| | - Jeffrey D Cirillo
- Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln, 203 VBS, Fair and East Campus Loop, Lincoln, NE 68583, USA1
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40
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Perregaux DG, Bhavsar K, Contillo L, Shi J, Gabel CA. Antimicrobial peptides initiate IL-1 beta posttranslational processing: a novel role beyond innate immunity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:3024-32. [PMID: 11884475 DOI: 10.4049/jimmunol.168.6.3024] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human monocytes stimulated with LPS produce large quantities of prointerleukin-1beta, but little of this cytokine product is released extracellularly as the mature biologically active species. To demonstrate efficient proteolytic cleavage and export, cytokine-producing cells require a secondary effector stimulus. In an attempt to identify agents that may serve as initiators of IL-1beta posttranslational processing in vivo, LPS-activated human monocytes were treated with several individual antimicrobial peptides. Two peptides derived from porcine neutrophils, protegrin (PTG)-1 and PTG-3, promoted rapid and efficient release of mature IL-1beta. The PTG-mediated response engaged a mechanism similar to that initiated by extracellular ATP acting via the P2X(7) receptor. Thus, both processes were disrupted by a caspase inhibitor, both were sensitive to ethacrynic acid and CP-424,174, two pharmacological agents that suppress posttranslational processing, and both were negated by elevation of extracellular potassium. Moreover, the PTGs, like ATP, promoted a dramatic change in monocyte morphology and a loss of membrane latency. The PTG response was concentration dependent and was influenced profoundly by components within the culture medium. In contrast, porcine neutrophil antimicrobial peptides PR-26 and PR-39 did not initiate IL-1beta posttranslational processing. The human defensin HNP-1 and the frog peptide magainin 1 elicited export of 17-kDa IL-1beta, but these agents were less efficient than PTGs. As a result of this ability to promote release of potent proinflammatory cytokines such as IL-1beta, select antimicrobial peptides may possess important immunomodulatory functions that extend beyond innate immunity.
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Affiliation(s)
- David G Perregaux
- Department of Antibacterials, Pfizer Global Research and Development, Pfizer, Inc., Groton, CT 06340, USA
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41
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Walev I, Hombach M, Bobkiewicz W, Fenske D, Bhakdi S, Husmann M. Resealing of large transmembrane pores produced by streptolysin O in nucleated cells is accompanied by NF-kappaB activation and downstream events. FASEB J 2002; 16:237-9. [PMID: 11744625 DOI: 10.1096/fj.01-0572fje] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Streptolysin O (SLO), archetype of a cholesterol-binding bacterial cytolysin, forms large pores in the plasma membrane of mammalian cells. We have recently reported that when a limited number of pores are generated in a cell, they can be sealed in a Ca++-dependent process. Here, we show that resealing is followed by the release of IL-6 and IL-8 from keratinocytes and from endothelial cells, both relevant targets for SLO attack. Production of cytokines by these cells was preceded by activation of transcription factor nuclear factor kappaB, which thus emerges as a common denominator of stress responses to various pore-forming agents, including alpha-toxin of Staphylococcus aureus and complement. Furthermore, we show that activation and cytokine release in response to an agent that forms a pore in the plasma membrane do not depend on paracrine effects, because supernatants of cells perforated by SLO did not activate bystander cells. The study provides definitive evidence that a transient transmembrane pore suffices to trigger productive transcriptional activation in a target cell.
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Affiliation(s)
- Iwan Walev
- Institute of Medical Microbiology, Johannes Gutenberg-University Mainz, D-55101 Mainz, Germany.
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42
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Brough D, Le Feuvre RA, Iwakura Y, Rothwell NJ. Purinergic (P2X7) receptor activation of microglia induces cell death via an interleukin-1-independent mechanism. Mol Cell Neurosci 2002; 19:272-80. [PMID: 11860279 DOI: 10.1006/mcne.2001.1054] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Activation of purinergic P2X7 receptors, principally by extracellular ATP, promotes the processing and release of the cytokine interleukin-1beta (IL-1beta) and induces cell death in activated microglia and macrophages. The objective of this study was to determine if IL-1beta release contributes directly to this cell death in microglia. Exposure of microglia to bacterial lipopolysaccharide (LPS) and ATP induced release of IL-1beta and IL-1alpha, as well as cell death. Neither cell death nor IL-1 release was observed in microglia lacking the P2X7 receptor. Microglia from mice lacking the IL-1beta gene demonstrated a profile of death identical to that of wild-type microglia in response to LPS and ATP. Thus, IL-1beta is not required for P2X7 receptor-stimulated microglial death.
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Affiliation(s)
- David Brough
- Division of Neuroscience, School of Biological Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
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43
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Lafleur RL, Malazdrewich C, Jeyaseelan S, Bleifield E, Abrahamsen MS, Maheswaran SK. Lipopolysaccharide enhances cytolysis and inflammatory cytokine induction in bovine alveolar macrophages exposed to Pasteurella (Mannheimia) haemolytica leukotoxin. Microb Pathog 2001; 30:347-57. [PMID: 11399141 DOI: 10.1006/mpat.2000.0438] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pasteurella (Mannheimia) haemolytica leukotoxin (Lkt) and lipopolysaccharide (LPS) are the primary virulence factors contributing to the pathogenesis of lung injury in bovine pneumonic pasteurellosis. Previous studies have characterized in vitro responses of bovine alveolar macrophages (AMs) to Lkt and LPS. Activation of AMs with Lkt or LPS causes induction of proinflammatory cytokines, and Lkt causes cytolysis of AMs at higher concentrations. Since AMs are exposed to both of these bacterial virulence factors during disease, previous studies may have underestimated the possibility of functional interactions between Lkt and LPS. The purpose of this study was to characterize the effect of simultaneous exposure to both Lkt and LPS on AM cytolysis and proinflammatory cytokine expression. Using cellular leakage of lactate dehydrogenase as an indirect measure of cytolysis, we studied AM responses to Lkt alone, LPS alone and Lkt+LPS. We found that 80-200 pg/ml LPS, which does not itself cause cytolysis, synergistically enhanced the cytolysis induced by 2-5 Lkt units (LU)/ml Lkt. Northern blot analysis demonstrated that synergism between Lkt and LPS resulted in increased levels of IL-8 mRNA, and that the kinetic patterns of TNF-alpha and IL-8 mRNA expression induced by Lkt+LPS differed from those induced by each agent separately. Finally, the WEHI 164 (clone 13) bioassay was used to show that Lkt/LPS synergism resulted in enhanced secretion of biologically active TNF-alpha. These results provide direct evidence of synergism between Lkt and LPS in AM cytolysis and inflammatory cytokine expression. Additional studies to characterize the molecular basis of this phenomenon are indicated.
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Affiliation(s)
- R L Lafleur
- Department of Veterinary PathoBiology, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota 55108, USA
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Perregaux DG, Labasi J, Laliberte R, Stam E, Solle M, Koller B, Griffiths R, Gabel CA. Interleukin-1? posttranslational processing?exploration of P2X7 receptor involvement. Drug Dev Res 2001. [DOI: 10.1002/ddr.1175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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45
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Cortajarena AL, Goñi FM, Ostolaza H. Glycophorin as a receptor for Escherichia coli alpha-hemolysin in erythrocytes. J Biol Chem 2001; 276:12513-9. [PMID: 11134007 DOI: 10.1074/jbc.m006792200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli alpha-hemolysin (HlyA) can lyse both red blood cells (RBC) and liposomes. However, the cells are lysed at HlyA concentrations 1-2 orders of magnitude lower than liposomes (large unilamellar vesicles). Treatment of RBC with trypsin, but not with chymotrypsin, reduces the sensitivity of RBC toward HlyA to the level of the liposomes. Since glycophorin, one of the main proteins in the RBC surface, can be hydrolyzed by trypsin much more readily than by chymotrypsin, the possibility was tested of a specific binding of HlyA to glycophorin. With this purpose, a number of experiments were performed. (a) HlyA was preincubated with purified glycophorin, after which it was found to be inactive against both RBC and liposomes. (b) Treatment of RBC with an anti-glycophorin antibody protected the cells against HlyA lysis. (c) Immobilized HlyA was able to bind glycophorin present in a detergent lysate of RBC ghosts. (d) Incorporation of glycophorin into pure phosphatidylcholine liposomes increased notoriously the sensitivity of the vesicles toward HlyA. (e) Treatment of the glycophorin-containing liposomes with trypsin reverted the vesicles to their original low sensitivity. The above results are interpreted in terms of glycophorin acting as a receptor for HlyA in RBC. The binding constant of HlyA for glycophorin was estimated, in RBC at sublytic HlyA concentrations, to be 1.5 x 10(-9) m.
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Affiliation(s)
- A L Cortajarena
- Unidad de Biofisica (Consejo Superior de Investigaciones Cientificas-UPV/EHU), and Departamento de Bioquimica, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, Aptdo. 644, Bilbao 48080, Spain
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46
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Dragneva Y, Anuradha CD, Valeva A, Hoffmann A, Bhakdi S, Husmann M. Subcytocidal attack by staphylococcal alpha-toxin activates NF-kappaB and induces interleukin-8 production. Infect Immun 2001; 69:2630-5. [PMID: 11254628 PMCID: PMC98200 DOI: 10.1128/iai.69.4.2630-2635.2001] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Formation of transmembrane pores by staphylococcal alpha-toxin can provoke a spectrum of events depending on target cell species and toxin dose, and in certain cases, repair of the lesions has been observed. Here, we report that transcriptional processes are activated as a response of cells to low toxin doses. Exposure of monocytic (THP-1) or epithelial (ECV304) cells to 40 to 160 ng/ml alpha-toxin provoked a drop in cellular ATP level that was followed by secretion of substantial amounts of interleukin-8 (IL-8). Cells transfected with constructs comprising the proximal IL-8 promoter fused to luciferase or to green fluorescent protein cDNA exhibited enhanced reporter gene expression following toxin treatment. Electrophoretic mobility shift and immunofluorescence assays demonstrated that IL-8 secretion was preceded by activation of NF-kappaB. Transfection experiments conducted with p65/p50 double-deficient cells showed that activation of the IL-8 promoter/reporter by toxin was absolutely dependent on NF-kappaB. In contrast, this transcription factor was not required for lesion repair. Attack of cells by low doses of a pore-forming toxin can lead to transcriptional gene activation, which is followed by production of mediators that may contribute to the initiation and propagation of inflammatory lesions.
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Affiliation(s)
- Y Dragneva
- Institute of Medical Microbiology and Hygiene, University of Mainz, Mainz, Germany
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Vesper SJ, Magnuson ML, Dearborn DG, Yike I, Haugland RA. Initial characterization of the hemolysin stachylysin from Stachybotrys chartarum. Infect Immun 2001; 69:912-6. [PMID: 11159985 PMCID: PMC97969 DOI: 10.1128/iai.69.2.912-916.2001] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Stachybotrys chartarum is a toxigenic fungus that has been associated with human health concerns, including pulmonary hemorrhage and hemosiderosis. This fungus produces a hemolysin, stachylysin, which in its apparent monomeric form has a molecular mass of 11,920 Da as determined by matrix-assisted laser desorption ionization-time of flight mass spectrometry. However, it appears to form polydispersed aggregates, which confounds understanding of the actual hemolytically active form. Exhaustive dialysis or heat treatment at 60 degrees C for 30 min inactivated stachylysin. Stachylysin is composed of about 40% nonpolar amino acids and contains two cysteine residues. Purified stachylysin required more than 6 h to begin lysing sheep erythrocytes, but by 48 h, lysis was complete. Stachylysin also formed pores in sheep erythrocyte membranes.
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Affiliation(s)
- S J Vesper
- U.S. Environmental Protection Agency, National Environmental Research Laboratory, Cincinnati, Ohio 45268, USA. Vesper.Stephen@EPA/gov
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Solle M, Labasi J, Perregaux DG, Stam E, Petrushova N, Koller BH, Griffiths RJ, Gabel CA. Altered cytokine production in mice lacking P2X(7) receptors. J Biol Chem 2001; 276:125-32. [PMID: 11016935 DOI: 10.1074/jbc.m006781200] [Citation(s) in RCA: 742] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The P2X(7) receptor (P2X(7)R) is an ATP-gated ion channel expressed by monocytes and macrophages. To directly address the role of this receptor in interleukin (IL)-1 beta post-translational processing, we have generated a P2X(7)R-deficient mouse line. P2X(7)R(-/-) macrophages respond to lipopolysaccharide and produce levels of cyclooxygenase-2 and pro-IL-1 beta comparable with those generated by wild-type cells. In response to ATP, however, pro-IL-1 beta produced by the P2X(7)R(-/-) cells is not externalized or activated by caspase-1. Nigericin, an alternate secretion stimulus, promotes release of 17-kDa IL-1 beta from P2X(7)R(-/-) macrophages. In response to in vivo lipopolysaccharide injection, both wild-type and P2X(7)R(-/-) animals display increases in peritoneal lavage IL-6 levels but no detectable IL-1. Subsequent ATP injection to wild-type animals promotes an increase in IL-1, which in turn leads to additional IL-6 production; similar increases did not occur in ATP-treated, LPS-primed P2X(7)R(-/-) animals. Absence of the P2X(7)R thus leads to an inability of peritoneal macrophages to release IL-1 in response to ATP. As a result of the IL-1 deficiency, in vivo cytokine signaling cascades are impaired in P2X(7)R-deficient animals. Together these results demonstrate that P2X(7)R activation can provide a signal that leads to maturation and release of IL-1 beta and initiation of a cytokine cascade.
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Affiliation(s)
- M Solle
- Department of Respiratory, Allergy, Immunology, Inflammation, and Infectious Diseases, Pfizer Inc., Groton, Connecticut 06340, USA
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Perregaux DG, McNiff P, Laliberte R, Conklyn M, Gabel CA. ATP acts as an agonist to promote stimulus-induced secretion of IL-1 beta and IL-18 in human blood. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:4615-23. [PMID: 11035104 DOI: 10.4049/jimmunol.165.8.4615] [Citation(s) in RCA: 203] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cultured monocytes and macrophages stimulated with LPS produce large quantities of proIL-1beta, but release little mature cytokine to the medium. The efficiency at which the procytokine is converted to its active 17-kDa species and released extracellularly is enhanced by treating cytokine-producing cells with a secretion stimulus such as ATP or nigericin. To determine whether this need for a secretion stimulus extends to blood, individual donors were bled twice daily for 4 consecutive days, and the collected blood samples were subjected to a two-step IL-1 production assay. LPS-activated blood samples generated cell-free IL-1beta, but levels of the extracellular cytokine were greatly increased by subsequent treatment with ATP or nigericin. Specificity and concentration requirements of the nucleotide triphosphate effect suggests a P2X(7) receptor involvement. Quantities of IL-1beta generated by an individual donor's blood in response to the LPS-only and LPS/ATP stimuli were relatively consistent over the 4-day period. Between donors, consistent differences in cytokine production capacity were observed. Blood samples treated with ATP also demonstrated enhanced IL-18 production, but TNF-alpha levels decreased. Among leukocytes, monocytes appeared to be the most affected cellular targets of the ATP stimulus. These studies indicate that an exogenous stimulus is required by blood for the efficient production of IL-1beta and IL-18, and suggest that circulating blood monocytes constitutively express a P2X(7)-like receptor.
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Affiliation(s)
- D G Perregaux
- Department of Respiratory, Allergy, Immunology, Inflammation, and Infectious Diseases, Pfizer Central Research, Groton, CT 06340, USA
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