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Lepesheva A, Grobarcikova M, Osickova A, Jurnecka D, Knoblochova S, Cizkova M, Osicka R, Sebo P, Masin J. Modification of the RTX domain cap by acyl chains of adapted length rules the formation of functional hemolysin pores. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184311. [PMID: 38570122 DOI: 10.1016/j.bbamem.2024.184311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/14/2024] [Accepted: 03/25/2024] [Indexed: 04/05/2024]
Abstract
The acylated pore-forming Repeats in ToXin (RTX) cytolysins α-hemolysin (HlyA) and adenylate cyclase toxin (CyaA) preferentially bind to β2 integrins of myeloid leukocytes but can also promiscuously bind and permeabilize cells lacking the β2 integrins. We constructed a HlyA1-563/CyaA860-1706 chimera that was acylated either by the toxin-activating acyltransferase CyaC, using sixteen carbon-long (C16) acyls, or by the HlyC acyltransferase using fourteen carbon-long (C14) acyls. Cytolysin assays with the C16- or C14-acylated HlyA/CyaA chimeric toxin revealed that the RTX domain of CyaA can functionally replace the RTX domain of HlyA only if it is modified by C16-acyls on the Lys983 residue of CyaA. The C16-monoacylated HlyA/CyaA chimera was as pore-forming and cytolytic as native HlyA, whereas the C14-acylated chimera exhibited very low pore-forming activity. Hence, the capacity of the RTX domain of CyaA to support the insertion of the N-terminal pore-forming domain into the target cell membrane, and promote formation of toxin pores, strictly depends on the modification of the Lys983 residue by an acyl chain of adapted length.
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Affiliation(s)
- Anna Lepesheva
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Michaela Grobarcikova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Sarka Knoblochova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Monika Cizkova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
| | - Jiri Masin
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
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Tessier E, Cheutin L, Garnier A, Vigne C, Tournier JN, Rougeaux C. Early Circulating Edema Factor in Inhalational Anthrax Infection: Does It Matter? Microorganisms 2024; 12:308. [PMID: 38399712 PMCID: PMC10891819 DOI: 10.3390/microorganisms12020308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
Anthrax toxins are critical virulence factors of Bacillus anthracis and Bacillus cereus strains that cause anthrax-like disease, composed of a common binding factor, the protective antigen (PA), and two enzymatic proteins, lethal factor (LF) and edema factor (EF). While PA is required for endocytosis and activity of EF and LF, several studies showed that these enzymatic factors disseminate within the body in the absence of PA after intranasal infection. In an effort to understand the impact of EF in the absence of PA, we used a fluorescent EF chimera to facilitate the study of endocytosis in different cell lines. Unexpectedly, EF was found inside cells in the absence of PA and showed a pole-dependent endocytosis. However, looking at enzymatic activity, PA was still required for EF to induce an increase in intracellular cAMP levels. Interestingly, the sequential delivery of EF and then PA rescued the rise in cAMP levels, indicating that PA and EF may functionally associate during intracellular trafficking, as well as it did at the cell surface. Our data shed new light on EF trafficking and the potential location of PA and EF association for optimal cytosolic delivery.
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Affiliation(s)
- Emilie Tessier
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Laurence Cheutin
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Annabelle Garnier
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Clarisse Vigne
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
| | - Jean-Nicolas Tournier
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
- Institut Pasteur, 75015 Paris, France
| | - Clémence Rougeaux
- Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France (C.R.)
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Osickova A, Knoblochova S, Bumba L, Man P, Kalaninova Z, Lepesheva A, Jurnecka D, Cizkova M, Biedermannova L, Goldsmith JA, Maynard JA, McLellan JS, Osicka R, Sebo P, Masin J. A conserved tryptophan in the acylated segment of RTX toxins controls their β 2 integrin-independent cell penetration. J Biol Chem 2023; 299:104978. [PMID: 37390987 PMCID: PMC10392135 DOI: 10.1016/j.jbc.2023.104978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/02/2023] Open
Abstract
The acylated Repeats in ToXins (RTX) leukotoxins, the adenylate cyclase toxin (CyaA) or α-hemolysin (HlyA), bind β2 integrins of leukocytes but also penetrate cells lacking these receptors. We show that the indoles of conserved tryptophans in the acylated segments, W876 of CyaA and W579 of HlyA, are crucial for β2 integrin-independent membrane penetration. Substitutions of W876 by aliphatic or aromatic residues did not affect acylation, folding, or the activities of CyaA W876L/F/Y variants on cells expressing high amounts of the β2 integrin CR3. However, toxin activity of CyaA W876L/F/Y on cells lacking CR3 was strongly impaired. Similarly, a W579L substitution selectively reduced HlyA W579L cytotoxicity towards cells lacking β2 integrins. Intriguingly, the W876L/F/Y substitutions increased the thermal stability (Tm) of CyaA by 4 to 8 °C but locally enhanced the accessibility to deuteration of the hydrophobic segment and of the interface of the two acylated loops. W876Q substitution (showing no increase in Tm), or combination of W876F with a cavity-filling V822M substitution (this combination decreasing the Tm closer to that of CyaA), yielded a milder defect of toxin activity on erythrocytes lacking CR3. Furthermore, the activity of CyaA on erythrocytes was also selectively impaired when the interaction of the pyrrolidine of P848 with the indole of W876 was ablated. Hence, the bulky indoles of residues W876 of CyaA, or W579 of HlyA, rule the local positioning of the acylated loops and enable a membrane-penetrating conformation in the absence of RTX toxin docking onto the cell membrane by β2 integrins.
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Affiliation(s)
- Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Sarka Knoblochova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ladislav Bumba
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Petr Man
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Zuzana Kalaninova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Sciences, Charles University, Prague, Czech Republic
| | - Anna Lepesheva
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Sciences, Charles University, Prague, Czech Republic
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Monika Cizkova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lada Biedermannova
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Vestec, Czech Republic
| | - Jory A Goldsmith
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, USA
| | - Jennifer A Maynard
- Department of Chemical Engineering, The University of Texas at Austin, Austin, USA
| | - Jason S McLellan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, USA
| | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
| | - Jiri Masin
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
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Rahman WU, Fiser R, Osicka R. Kingella kingae RtxA toxin interacts with sialylated gangliosides. Microb Pathog 2023:106200. [PMID: 37315629 DOI: 10.1016/j.micpath.2023.106200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 06/11/2023] [Accepted: 06/12/2023] [Indexed: 06/16/2023]
Abstract
The membrane-damaging RTX family cytotoxin RtxA is a key virulence factor of the emerging pediatric pathogen Kingella kingae, but little is known about the mechanism of RtxA binding to host cells. While we have previously shown that RtxA binds cell surface glycoproteins, here we demonstrate that the toxin also binds different types of gangliosides. The recognition of gangliosides by RtxA depended on sialic acid side groups of ganglioside glycans. Moreover, binding of RtxA to epithelial cells was significantly decreased in the presence of free sialylated gangliosides, which inhibited cytotoxic activity of the toxin. These results suggest that RtxA utilizes sialylated gangliosides as ubiquitous cell membrane receptor molecules on host cells to exert its cytotoxic action and support K. kingae infection.
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Affiliation(s)
- Waheed Ur Rahman
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Radovan Fiser
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic; Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
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5
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Chacko FM, Schmitt L. Interaction of RTX toxins with the host cell plasma membrane. Biol Chem 2023:hsz-2022-0336. [PMID: 36907826 DOI: 10.1515/hsz-2022-0336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/27/2023] [Indexed: 03/14/2023]
Abstract
Repeats in ToXins (RTX) protein family is a group of exoproteins secreted by Type 1 secretion system (T1SS) of several Gram-negative bacteria. The term RTX is derived from the characteristic nonapeptide sequence (GGxGxDxUx) present at the C-terminus of the protein. This RTX domain binds to calcium ions in the extracellular medium after being secreted out of the bacterial cells, and this facilitates folding of the entire protein. The secreted protein then binds to the host cell membrane and forms pores via a complex pathway, which eventually leads to the cell lysis. In this review, we summarize two different pathways in which RTX toxins interact with host cell membrane and discuss the possible reasons for specific and unspecific activity of RTX toxins to different types of host cells.
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Affiliation(s)
- Feby M Chacko
- Institute of Biochemistry, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
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Carrica MDC, Gorgojo JP, Lamberti YA, Valdez HA, Rodriguez ME. Bordetella parapertussis adenylate cyclase toxin promotes the bacterial survival to the encounter with macrophages. Microb Pathog 2023; 174:105898. [PMID: 36460144 DOI: 10.1016/j.micpath.2022.105898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/30/2022]
Abstract
B. parapertussis is a whooping cough etiological agent, whose incidence in the population has increased remarkably. Virulence factors involved in the bacterial infection, however, remain poorly investigated. We here studied the role of adenylate cyclase (CyaA), the main toxin of B. parapertussis, in the outcome of the bacterial interaction with macrophages. Our results showed that B. parapertussis CyaA intoxicates human macrophages, prevents bacterial phagocytosis and precludes phago-lysosomal fusion eventually promoting the bacterial survival to the encounter with these immune cells. Accordingly, we found that B. parapertussis CyaA induces the transcriptional downregulation of host genes encoding for antimicrobial peptides, proteins involved in bacterial intracellular killing, and the pro-inflammatory cytokine TNF-α, while induces the upregulation of the anti-inflammatory cytokine IL-10. Together with previous reports suggesting a protective role of B. parapertussis CyaA against neutrophils bactericidal activity, the results of this study suggest a central role of CyaA in B. parapertussis immune evasion and persistence.
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Affiliation(s)
- Mariela Del Carmen Carrica
- CINDEFI (UNLP CONICET La Plata), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina.
| | - Juan Pablo Gorgojo
- CINDEFI (UNLP CONICET La Plata), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Yanina Andrea Lamberti
- CINDEFI (UNLP CONICET La Plata), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Hugo Alberto Valdez
- CINDEFI (UNLP CONICET La Plata), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Maria Eugenia Rodriguez
- CINDEFI (UNLP CONICET La Plata), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina.
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7
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Filipi K, Rahman WU, Osickova A, Osicka R. Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins. Microorganisms 2022; 10:microorganisms10030518. [PMID: 35336094 PMCID: PMC8953716 DOI: 10.3390/microorganisms10030518] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/04/2022] Open
Abstract
The Gram-negative bacterium Kingella kingae is part of the commensal oropharyngeal flora of young children. As detection methods have improved, K. kingae has been increasingly recognized as an emerging invasive pathogen that frequently causes skeletal system infections, bacteremia, and severe forms of infective endocarditis. K. kingae secretes an RtxA cytotoxin, which is involved in the development of clinical infection and belongs to an ever-growing family of cytolytic RTX (Repeats in ToXin) toxins secreted by Gram-negative pathogens. All RTX cytolysins share several characteristic structural features: (i) a hydrophobic pore-forming domain in the N-terminal part of the molecule; (ii) an acylated segment where the activation of the inactive protoxin to the toxin occurs by a co-expressed toxin-activating acyltransferase; (iii) a typical calcium-binding RTX domain in the C-terminal portion of the molecule with the characteristic glycine- and aspartate-rich nonapeptide repeats; and (iv) a C-proximal secretion signal recognized by the type I secretion system. RTX toxins, including RtxA from K. kingae, have been shown to act as highly efficient ‘contact weapons’ that penetrate and permeabilize host cell membranes and thus contribute to the pathogenesis of bacterial infections. RtxA was discovered relatively recently and the knowledge of its biological role remains limited. This review describes the structure and function of RtxA in the context of the most studied RTX toxins, the knowledge of which may contribute to a better understanding of the action of RtxA in the pathogenesis of K. kingae infections.
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Bordetella Adenylate Cyclase Toxin Elicits Airway Mucin Secretion through Activation of the cAMP Response Element Binding Protein. Int J Mol Sci 2021; 22:ijms22169064. [PMID: 34445770 PMCID: PMC8396599 DOI: 10.3390/ijms22169064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/14/2021] [Accepted: 08/19/2021] [Indexed: 12/30/2022] Open
Abstract
The mucus layer protects airway epithelia from damage by noxious agents. Intriguingly, Bordetella pertussis bacteria provoke massive mucus production by nasopharyngeal epithelia during the initial coryza-like catarrhal stage of human pertussis and the pathogen transmits in mucus-containing aerosol droplets expelled by sneezing and post-nasal drip-triggered cough. We investigated the role of the cAMP-elevating adenylate cyclase (CyaA) and pertussis (PT) toxins in the upregulation of mucin production in B. pertussis-infected airway epithelia. Using human pseudostratified airway epithelial cell layers cultured at air–liquid interface (ALI), we show that purified CyaA and PT toxins (100 ng/mL) can trigger production of the major airway mucins Muc5AC and Muc5B. Upregulation of mucin secretion involved activation of the cAMP response element binding protein (CREB) and was blocked by the 666-15-Calbiochem inhibitor of CREB-mediated gene transcription. Intriguingly, a B. pertussis mutant strain secreting only active PT and producing the enzymatically inactive CyaA-AC– toxoid failed to trigger any important mucus production in infected epithelial cell layers in vitro or in vivo in the tracheal epithelia of intranasally infected mice. In contrast, the PT– toxoid-producing B. pertussis mutant secreting the active CyaA toxin elicited a comparable mucin production as infection of epithelial cell layers or tracheal epithelia of infected mice by the wild-type B. pertussis secreting both PT and CyaA toxins. Hence, the cAMP-elevating activity of B. pertussis-secreted CyaA was alone sufficient for activation of mucin production through a CREB-dependent mechanism in B. pertussis-infected airway epithelia in vivo.
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Distribution of adenylyl cyclase/cAMP phosphodiesterase gene, CAPE, in streptophytes reproducing via motile sperm. Sci Rep 2021; 11:10054. [PMID: 33980894 PMCID: PMC8115329 DOI: 10.1038/s41598-021-89539-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 04/28/2021] [Indexed: 02/03/2023] Open
Abstract
We recently isolated a novel adenylyl cyclase/cAMP phosphodiesterase gene from the liverwort, Marchantia polymorpha. The protein encoded by this gene has a class III adenylyl cyclase (AC) in the C-terminal domain and class I phosphodiesterase (PDE) in the N-terminal domain; therefore, we named it CAPE (COMBINED AC with PDE). CAPE protein is likely involved in spermatogenesis and sperm motility due to its tissue-specific expression pattern in M. polymorpha and the distribution of CAPE genes in streptophytes. However, little is known about the distribution of CAPE in gymnosperms that use motile sperm for fertilization, such as cycads and ginkgo. The present study aimed to isolate CAPE genes from the cycad, Cycas revoluta, the ginkgo, Ginkgo biloba, and the hornwort, Anthoceros agerestis. Sequences with high homology to CAPE were obtained from these species. Our analyses revealed that all plant taxonomic groups reproducing via motile sperm possessed CAPE, whereas those that do not produce motile sperm did not possess CAPE, with one exception in gymnosperm Cupressales. The phylogenic distribution of CAPE almost corresponds to the evolutionary history of motile sperm production and further suggests that CAPE may be involved in sexual reproduction process using motile sperm in streptophytes.
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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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Knapp O, Benz R. Membrane Activity and Channel Formation of the Adenylate Cyclase Toxin (CyaA) of Bordetella pertussis in Lipid Bilayer Membranes. Toxins (Basel) 2020; 12:toxins12030169. [PMID: 32164365 PMCID: PMC7150934 DOI: 10.3390/toxins12030169] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/20/2020] [Accepted: 02/22/2020] [Indexed: 12/14/2022] Open
Abstract
The Gram-negative bacterium Bordetella pertussis is the cause of whooping cough. One of its pathogenicity factors is the adenylate cyclase toxin (CyaA) secreted by a Type I export system. The 1706 amino acid long CyaA (177 kDa) belongs to the continuously increasing family of repeat in toxin (RTX) toxins because it contains in its C-terminal half a high number of nine-residue tandem repeats. The protein exhibits cytotoxic and hemolytic activities that target primarily myeloid phagocytic cells expressing the αMβ2 integrin receptor (CD11b/CD18). CyaA represents an exception among RTX cytolysins because the first 400 amino acids from its N-terminal end possess a calmodulin-activated adenylate cyclase (AC) activity. The entry of the AC into target cells is not dependent on the receptor-mediated endocytosis pathway and penetrates directly across the cytoplasmic membrane of a variety of epithelial and immune effector cells. The hemolytic activity of CyaA is rather low, which may have to do with its rather low induced permeability change of target cells and its low conductance in lipid bilayer membranes. CyaA forms highly cation-selective channels in lipid bilayers that show a strong dependence on aqueous pH. The pore-forming activity of CyaA but not its single channel conductance is highly dependent on Ca2+ concentration with a half saturation constant of about 2 to 4 mM.
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Affiliation(s)
- Oliver Knapp
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany
- Correspondence: (O.K.); (R.B.)
| | - Roland Benz
- Rudolf-Virchow-Center, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany
- Correspondence: (O.K.); (R.B.)
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12
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Scanlon K, Skerry C, Carbonetti N. Role of Major Toxin Virulence Factors in Pertussis Infection and Disease Pathogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1183:35-51. [PMID: 31376138 DOI: 10.1007/5584_2019_403] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Bordetella pertussis produces several toxins that affect host-pathogen interactions. Of these, the major toxins that contribute to pertussis infection and disease are pertussis toxin, adenylate cyclase toxin-hemolysin and tracheal cytotoxin. Pertussis toxin is a multi-subunit protein toxin that inhibits host G protein-coupled receptor signaling, causing a wide array of effects on the host. Adenylate cyclase toxin-hemolysin is a single polypeptide, containing an adenylate cyclase enzymatic domain coupled to a hemolysin domain, that primarily targets phagocytic cells to inhibit their antibacterial activities. Tracheal cytotoxin is a fragment of peptidoglycan released by B. pertussis that elicits damaging inflammatory responses in host cells. This chapter describes these three virulence factors of B. pertussis, summarizing background information and focusing on the role of each toxin in infection and disease pathogenesis, as well as their role in pertussis vaccination.
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Affiliation(s)
- Karen Scanlon
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ciaran Skerry
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Nicholas Carbonetti
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, USA.
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Chenal A, Ladant D. Bioengineering of Bordetella pertussis Adenylate Cyclase Toxin for Antigen-Delivery and Immunotherapy. Toxins (Basel) 2018; 10:E302. [PMID: 30037010 PMCID: PMC6070788 DOI: 10.3390/toxins10070302] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/16/2018] [Accepted: 07/18/2018] [Indexed: 11/16/2022] Open
Abstract
The adenylate cyclase toxin (CyaA) is one of the major virulence factors of Bordetella pertussis, the causative agent of whooping cough. CyaA is able to invade eukaryotic cells where, upon activation by endogenous calmodulin, it synthesizes massive amounts of cAMP that alters cellular physiology. The CyaA toxin is a 1706 residues-long bifunctional protein: the catalytic domain is located in the 400 amino-proximal residues, whereas the carboxy-terminal 1306 residues are implicated in toxin binding to the cellular receptor, the αMβ₂ (CD11b/CD18) integrin, and subsequently in the translocation of the catalytic domain across the cytoplasmic membrane of the target cells. Indeed, this protein is endowed with the unique capability of delivering its N-terminal catalytic domain directly across the plasma membrane of eukaryotic target cells. These properties have been exploited to engineer the CyaA toxin as a potent non-replicating vector able to deliver antigens into antigen presenting cells and elicit specific cell-mediated immune responses. Antigens of interest can be inserted into the CyaA protein to yield recombinant molecules that are targeted in vivo to dendritic cells, where the antigens are processed and presented by the major class I and class II histocompatibility complexes (MHC-I and II). CyaA turned out to be a remarkably effective and versatile vaccine vector capable of inducing all the components of the immune response (T-CD4, T-CD8, and antibody). In this chapter, we summarize the basic knowledge on the adenylate cyclase toxin and then describe the application of CyaA in vaccinology, including some recent results of clinical trials of immunotherapy using a recombinant CyaA vaccine.
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Affiliation(s)
- Alexandre Chenal
- Institut Pasteur, Biochemistry of Macromolecular Interactions Unit, UMR CNRS 3528, Structural Biology and Chemistry Department, 28 rue du Docteur Roux, 75724 Paris CEDEX 15, France.
| | - Daniel Ladant
- Institut Pasteur, Biochemistry of Macromolecular Interactions Unit, UMR CNRS 3528, Structural Biology and Chemistry Department, 28 rue du Docteur Roux, 75724 Paris CEDEX 15, France.
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O'Brien DP, Perez ACS, Karst J, Cannella SE, Enguéné VYN, Hessel A, Raoux-Barbot D, Voegele A, Subrini O, Davi M, Guijarro JI, Raynal B, Baron B, England P, Hernandez B, Ghomi M, Hourdel V, Malosse C, Chamot-Rooke J, Vachette P, Durand D, Brier S, Ladant D, Chenal A. Calcium-dependent disorder-to-order transitions are central to the secretion and folding of the CyaA toxin of Bordetella pertussis, the causative agent of whooping cough. Toxicon 2018; 149:37-44. [DOI: 10.1016/j.toxicon.2018.01.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 11/20/2017] [Accepted: 01/10/2018] [Indexed: 02/07/2023]
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15
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Hasan S, Kulkarni NN, Asbjarnarson A, Linhartova I, Osicka R, Sebo P, Gudmundsson GH. Bordetella pertussis Adenylate Cyclase Toxin Disrupts Functional Integrity of Bronchial Epithelial Layers. Infect Immun 2018; 86:e00445-17. [PMID: 29203545 PMCID: PMC5820963 DOI: 10.1128/iai.00445-17] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 11/28/2017] [Indexed: 12/14/2022] Open
Abstract
The airway epithelium restricts the penetration of inhaled pathogens into the underlying tissue and plays a crucial role in the innate immune defense against respiratory infections. The whooping cough agent, Bordetella pertussis, adheres to ciliated cells of the human airway epithelium and subverts its defense functions through the action of secreted toxins and other virulence factors. We examined the impact of B. pertussis infection and of adenylate cyclase toxin-hemolysin (CyaA) action on the functional integrity of human bronchial epithelial cells cultured at the air-liquid interface (ALI). B. pertussis adhesion to the apical surface of polarized pseudostratified VA10 cell layers provoked a disruption of tight junctions and caused a drop in transepithelial electrical resistance (TEER). The reduction of TEER depended on the capacity of the secreted CyaA toxin to elicit cAMP signaling in epithelial cells through its adenylyl cyclase enzyme activity. Both purified CyaA and cAMP-signaling drugs triggered a decrease in the TEER of VA10 cell layers. Toxin-produced cAMP signaling caused actin cytoskeleton rearrangement and induced mucin 5AC production and interleukin-6 (IL-6) secretion, while it inhibited the IL-17A-induced secretion of the IL-8 chemokine and of the antimicrobial peptide beta-defensin 2. These results indicate that CyaA toxin activity compromises the barrier and innate immune functions of Bordetella-infected airway epithelia.
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Affiliation(s)
- Shakir Hasan
- Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic
| | | | | | - Irena Linhartova
- Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic
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Structure-Function Relationships Underlying the Capacity of Bordetella Adenylate Cyclase Toxin to Disarm Host Phagocytes. Toxins (Basel) 2017; 9:toxins9100300. [PMID: 28946636 PMCID: PMC5666347 DOI: 10.3390/toxins9100300] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 01/18/2023] Open
Abstract
Bordetellae, pathogenic to mammals, produce an immunomodulatory adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) that enables them to overcome the innate immune defense of the host. CyaA subverts host phagocytic cells by an orchestrated action of its functional domains, where an extremely catalytically active adenylyl cyclase enzyme is delivered into phagocyte cytosol by a pore-forming repeat-in-toxin (RTX) cytolysin moiety. By targeting sentinel cells expressing the complement receptor 3, known as the CD11b/CD18 (αMβ₂) integrin, CyaA compromises the bactericidal functions of host phagocytes and supports infection of host airways by Bordetellae. Here, we review the state of knowledge on structural and functional aspects of CyaA toxin action, placing particular emphasis on signaling mechanisms by which the toxin-produced 3',5'-cyclic adenosine monophosphate (cAMP) subverts the physiology of phagocytic cells.
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17
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Understanding the Mechanism of Translocation of Adenylate Cyclase Toxin across Biological Membranes. Toxins (Basel) 2017; 9:toxins9100295. [PMID: 28934133 PMCID: PMC5666342 DOI: 10.3390/toxins9100295] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 01/05/2023] Open
Abstract
Adenylate cyclase toxin (ACT) is one of the principal virulence factors secreted by the whooping cough causative bacterium Bordetella pertussis, and it has a critical role in colonization of the respiratory tract and establishment of the disease. ACT targets phagocytes via binding to the CD11b/CD18 integrin and delivers its N-terminal adenylate cyclase (AC) domain directly to the cell cytosol, where it catalyzes unregulated conversion of cytosolic ATP into cAMP upon activation by binding to cellular calmodulin. High cAMP levels disrupt bactericidal functions of the immune cells, ultimately leading to cell death. In spite of its relevance in the ACT biology, the mechanism by which its ≈400 amino acid-long AC domain is transported through the target plasma membrane, and is released into the target cytosol, remains enigmatic. This article is devoted to refresh our knowledge on the mechanism of AC translocation across biological membranes. Two models, the so-called "two-step model" and the recently-proposed "toroidal pore model", will be considered.
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18
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Phospholipase A activity of adenylate cyclase toxin mediates translocation of its adenylate cyclase domain. Proc Natl Acad Sci U S A 2017; 114:E6784-E6793. [PMID: 28760979 DOI: 10.1073/pnas.1701783114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adenylate cyclase toxin (ACT or CyaA) plays a crucial role in respiratory tract colonization and virulence of the whooping cough causative bacterium Bordetella pertussis Secreted as soluble protein, it targets myeloid cells expressing the CD11b/CD18 integrin and on delivery of its N-terminal adenylate cyclase catalytic domain (AC domain) into the cytosol, generates uncontrolled toxic levels of cAMP that ablates bactericidal capacities of phagocytes. Our study deciphers the fundamentals of the heretofore poorly understood molecular mechanism by which the ACT enzyme domain directly crosses the host cell membrane. By combining molecular biology, biochemistry, and biophysics techniques, we discover that ACT has intrinsic phospholipase A (PLA) activity, and that such activity determines AC translocation. Moreover, we show that elimination of the ACT-PLA activity abrogates ACT toxicity in macrophages, particularly at toxin concentrations close to biological reality of bacterial infection. Our data support a molecular mechanism in which in situ generation of nonlamellar lysophospholipids by ACT-PLA activity into the cell membrane would form, likely in combination with membrane-interacting ACT segments, a proteolipidic toroidal pore through which AC domain transfer could directly take place. Regulation of ACT-PLA activity thus emerges as novel target for therapeutic control of the disease.
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Wang X, Stapleton JA, Klesmith JR, Hewlett EL, Whitehead TA, Maynard JA. Fine Epitope Mapping of Two Antibodies Neutralizing the Bordetella Adenylate Cyclase Toxin. Biochemistry 2017; 56:1324-1336. [PMID: 28177609 DOI: 10.1021/acs.biochem.6b01163] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Adenylate cyclase toxin (ACT) is an important Bordetella pertussis virulence factor that is not included in current acellular pertussis vaccines. We previously demonstrated that immunization with the repeat-in-toxin (RTX) domain of ACT elicits neutralizing antibodies in mice and discovered the first two antibodies to neutralize ACT activities by occluding the receptor-binding site. Here, we fully characterize these antibodies and their epitopes. Both antibodies bind ACT with low nanomolar affinity and cross-react with ACT homologues produced by B. parapertussis and B. bronchiseptica. Antibody M1H5 binds B. pertussis RTX751 ∼100-fold tighter than RTX751 from the other two species, while antibody M2B10 has similar affinity for all three variants. To initially map the antibody epitopes, we generated a series of ACT chimeras and truncation variants, which implicated the repeat blocks II-III. To identify individual epitope residues, we displayed randomly mutated RTX751 libraries on yeast and isolated clones with decreased antibody binding by flow cytometry. Next-generation sequencing identified candidate epitope residues on the basis of enrichment of clones with mutations at specific positions. These epitopes form two adjacent surface patches on a predicted structural model of the RTX751 domain, one for each antibody. Notably, the cellular receptor also binds within blocks II-III and shares at least one residue with the M1H5 epitope. The RTX751 model supports the notion that the antibody and receptor epitopes overlap. These data provide insight into mechanisms of ACT neutralization and guidance for engineering more stable RTX variants that may be more appropriate vaccine antigens.
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Affiliation(s)
- Xianzhe Wang
- Department of Chemical Engineering, University of Texas at Austin , Austin, Texas 78712, United States
| | - James A Stapleton
- Department of Chemical Engineering and Materials Science, Michigan State University , East Lansing, Michigan 48824, United States
| | - Justin R Klesmith
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Erik L Hewlett
- Department of Medicine, University of Virginia , Charlottesville, Virginia 22906, United States
| | - Timothy A Whitehead
- Department of Chemical Engineering and Materials Science, Michigan State University , East Lansing, Michigan 48824, United States.,Department of Biosystems and Agricultural Engineering, Michigan State University , East Lansing, Michigan 48824, United States
| | - Jennifer A Maynard
- Department of Chemical Engineering, University of Texas at Austin , Austin, Texas 78712, United States
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Cannella SE, Ntsogo Enguéné VY, Davi M, Malosse C, Sotomayor Pérez AC, Chamot-Rooke J, Vachette P, Durand D, Ladant D, Chenal A. Stability, structural and functional properties of a monomeric, calcium-loaded adenylate cyclase toxin, CyaA, from Bordetella pertussis. Sci Rep 2017; 7:42065. [PMID: 28186111 PMCID: PMC5301233 DOI: 10.1038/srep42065] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 01/04/2017] [Indexed: 12/21/2022] Open
Abstract
Bordetella pertussis, the causative agent of whooping cough, secretes an adenylate cyclase toxin, CyaA, which invades eukaryotic cells and alters their physiology by cAMP overproduction. Calcium is an essential cofactor of CyaA, as it is the case for most members of the Repeat-in-ToXins (RTX) family. We show that the calcium-bound, monomeric form of CyaA, hCyaAm, conserves its permeabilization and haemolytic activities, even in a fully calcium-free environment. In contrast, hCyaAm requires sub-millimolar calcium in solution for cell invasion, indicating that free calcium in solution is involved in the CyaA toxin translocation process. We further report the first in solution structural characterization of hCyaAm, as deduced from SAXS, mass spectrometry and hydrodynamic studies. We show that hCyaAm adopts a compact and stable state that can transiently conserve its conformation even in a fully calcium-free environment. Our results therefore suggest that in hCyaAm, the C-terminal RTX-domain is stabilized in a high-affinity calcium-binding state by the N-terminal domains while, conversely, calcium binding to the C-terminal RTX-domain strongly stabilizes the N-terminal regions. Hence, the different regions of hCyaAm appear tightly connected, leading to stabilization effects between domains. The hysteretic behaviour of CyaA in response to calcium is likely shared by other RTX cytolysins.
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Affiliation(s)
- Sara E. Cannella
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | | | - Marilyne Davi
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Christian Malosse
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | | | - Julia Chamot-Rooke
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Patrice Vachette
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Université Paris-Sud, F-91405 ORSAY Cedex, France
| | - Dominique Durand
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Université Paris-Sud, F-91405 ORSAY Cedex, France
| | - Daniel Ladant
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Alexandre Chenal
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
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Use of a Toxin Neutralization Assay To Characterize the Serologic Response to Adenylate Cyclase Toxin after Infection with Bordetella pertussis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00370-16. [PMID: 27760780 DOI: 10.1128/cvi.00370-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/12/2016] [Indexed: 11/20/2022]
Abstract
Adenylate cyclase toxin (ACT) is an essential virulence factor of Bordetella pertussis, and antibodies to ACT protect against B. pertussis infection in mice. The toxin is therefore a strong candidate antigen for addition to future acellular pertussis vaccines. In order to characterize the functionality of the immunologic response to ACT after infection, we developed an assay for testing the ability of serum samples from subjects infected with B. pertussis to neutralize ACT-induced cytotoxicity in J774 macrophage cells. Baboons develop neutralizing anti-ACT antibodies following infection with B. pertussis, and all sera from baboons with positive anti-ACT IgG enzyme-linked immunosorbent assay (ELISA) results neutralized ACT cytotoxicity. The toxin neutralization assay (TNA) was positive in some baboon sera in which ELISA remained negative. Of serum samples obtained from humans diagnosed with pertussis by PCR, anti-ACT IgG ELISA was positive in 72%, and TNA was positive in 83%. All samples positive for anti-ACT IgG ELISA were positive by TNA, and none of the samples from humans without pertussis neutralized toxin activity. These findings indicate that antibodies to ACT generated following infection with B. pertussis consistently neutralize toxin-induced cytotoxicity and that TNA can be used to improve understanding of the immunologic response to ACT after infection or vaccination.
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22
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Williams JM, Tsai B. Intracellular trafficking of bacterial toxins. Curr Opin Cell Biol 2016; 41:51-6. [PMID: 27084982 DOI: 10.1016/j.ceb.2016.03.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 03/23/2016] [Accepted: 03/24/2016] [Indexed: 11/18/2022]
Abstract
Bacterial toxins often translocate across a cellular membrane to gain access into the host cytosol, modifying cellular components in order to exert their toxic effects. To accomplish this feat, these toxins traffic to a membrane penetration site where they undergo conformational changes essential to eject the toxin's catalytic subunit into the cytosol. In this brief review, we highlight recent findings that elucidate both the trafficking pathways and membrane translocation mechanisms of toxins that cross the plasma, endosomal, or endoplasmic reticulum (ER) membrane. These findings not only illuminate the specific nature of the host-toxin interactions during entry, but should also provide additional therapeutic strategies to prevent or alleviate the bacterial toxin-induced diseases.
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Affiliation(s)
- Jeffrey M Williams
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Room 3043, Ann Arbor, MI 48109, United States
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Room 3043, Ann Arbor, MI 48109, United States.
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Wald T, Osickova A, Masin J, Liskova PM, Petry-Podgorska I, Matousek T, Sebo P, Osicka R. Transmembrane segments of complement receptor 3 do not participate in cytotoxic activities but determine receptor structure required for action of Bordetella adenylate cyclase toxin. Pathog Dis 2016; 74:ftw008. [PMID: 26802078 DOI: 10.1093/femspd/ftw008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2016] [Indexed: 11/13/2022] Open
Abstract
Adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) of the whooping cough agent Bordetella pertussis penetrates phagocytes expressing the integrin complement receptor 3 (CR3, CD11b/CD18, α(M)β(2) or Mac-1). CyaA translocates its adenylate cyclase (AC) enzyme domain into cell cytosol and catalyzes unregulated conversion of ATP to cAMP, thereby subverting cellular signaling. In parallel, CyaA forms small cation-selective membrane pores that permeabilize cells for potassium efflux, contributing to cytotoxicity of CyaA and eventually provoking colloid-osmotic cell lysis. To investigate whether the single-pass α-helical transmembrane segments of CR3 subunits CD11b and CD18 do directly participate in AC domain translocation and/or pore formation by the toxin, we expressed in CHO cells variants of CR3 that contained artificial transmembrane segments, or lacked the transmembrane segment(s) at all. The results demonstrate that the transmembrane segments of CR3 are not directly involved in the cytotoxic activities of CyaA but serve for maintaining CR3 in a conformation that is required for efficient toxin binding and action.
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Affiliation(s)
- Tomas Wald
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43, Prague 2, Czech Republic
| | - Jiri Masin
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic
| | - Petra M Liskova
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Vinicna 5, 128 44 Prague 2, Czech Republic
| | - Inga Petry-Podgorska
- Institute of Analytical Chemistry of the CAS, v. v. i., Veveri 97, 602 00 Brno, Czech Republic
| | - Tomas Matousek
- Institute of Analytical Chemistry of the CAS, v. v. i., Veveri 97, 602 00 Brno, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the CAS, v. v. i., Videnska 1083, 142 20, Prague 4, Czech Republic
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Iwaki M, Konda T. Adenylate cyclase toxin-mediated delivery of the S1 subunit of pertussis toxin into mammalian cells. Pathog Dis 2015; 74:ftv110. [PMID: 26607401 DOI: 10.1093/femspd/ftv110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2015] [Indexed: 11/14/2022] Open
Abstract
The adenylate cyclase toxin (ACT) of Bordetella pertussis internalizes its catalytic domain into target cells. ACT can function as a tool for delivering foreign protein antigen moieties into immune effector cells to induce a cytotoxic T lymphocyte response. In this study, we replaced the catalytic domain of ACT with an enzymatically active protein moiety, the S1 (ADP-ribosyltransferase) subunit of pertussis toxin (PT). The S1 moiety was successfully internalized independent of endocytosis into sheep erythrocytes. The introduced polypeptide exhibited ADP-ribosyltransferase activity in CHO cells and induced clustering typical to PT. The results indicate that ACT can act as a vehicle for not only epitopes but also enzymatically active peptides to mammalian cells.
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Affiliation(s)
- Masaaki Iwaki
- Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Toshifumi Konda
- Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
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25
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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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26
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Masin J, Osicka R, Bumba L, Sebo P. Bordetella adenylate cyclase toxin: a unique combination of a pore-forming moiety with a cell-invading adenylate cyclase enzyme. Pathog Dis 2015; 73:ftv075. [PMID: 26391732 DOI: 10.1093/femspd/ftv075] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2015] [Indexed: 12/30/2022] Open
Abstract
The adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) is a key virulence factor of the whooping cough agent Bordetella pertussis. CyaA targets myeloid phagocytes expressing the complement receptor 3 (CR3, known as αMβ2 integrin CD11b/CD18 or Mac-1) and translocates by a poorly understood mechanism directly across the cytoplasmic membrane into cell cytosol of phagocytes an adenylyl cyclase(AC) enzyme. This binds intracellular calmodulin and catalyzes unregulated conversion of cytosolic ATP into cAMP. Among other effects, this yields activation of the tyrosine phosphatase SHP-1, BimEL accumulation and phagocyte apoptosis induction. In parallel, CyaA acts as a cytolysin that forms cation-selective pores in target membranes. Direct penetration of CyaA into the cytosol of professional antigen-presenting cells allows the use of an enzymatically inactive CyaA toxoid as a tool for delivery of passenger antigens into the cytosolic pathway of processing and MHC class I-restricted presentation, which can be exploited for induction of antigen-specific CD8(+) cytotoxic T-lymphocyte immune responses.
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Affiliation(s)
- Jiri Masin
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Radim Osicka
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Ladislav Bumba
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Peter Sebo
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
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27
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Cerny O, Kamanova J, Masin J, Bibova I, Skopova K, Sebo P. Bordetella pertussis Adenylate Cyclase Toxin Blocks Induction of Bactericidal Nitric Oxide in Macrophages through cAMP-Dependent Activation of the SHP-1 Phosphatase. THE JOURNAL OF IMMUNOLOGY 2015; 194:4901-13. [PMID: 25876760 DOI: 10.4049/jimmunol.1402941] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 03/10/2015] [Indexed: 12/23/2022]
Abstract
The adenylate cyclase toxin-hemolysin (CyaA) plays a key role in the virulence of Bordetella pertussis. CyaA penetrates complement receptor 3-expressing phagocytes and catalyzes uncontrolled conversion of cytosolic ATP to the key second messenger molecule cAMP. This paralyzes the capacity of neutrophils and macrophages to kill bacteria by complement-dependent oxidative burst and opsonophagocytic mechanisms. We show that cAMP signaling through the protein kinase A (PKA) pathway activates Src homology domain 2 containing protein tyrosine phosphatase (SHP) 1 and suppresses production of bactericidal NO in macrophage cells. Selective activation of PKA by the cell-permeable analog N(6)-benzoyladenosine-3',5'-cyclic monophosphate interfered with LPS-induced inducible NO synthase (iNOS) expression in RAW264.7 macrophages, whereas inhibition of PKA by H-89 largely restored the production of iNOS in CyaA-treated murine macrophages. CyaA/cAMP signaling induced SHP phosphatase-dependent dephosphorylation of the c-Fos subunit of the transcription factor AP-1 and thereby inhibited TLR4-triggered induction of iNOS gene expression. Selective small interfering RNA knockdown of SHP-1, but not of the SHP-2 phosphatase, rescued production of TLR-inducible NO in toxin-treated cells. Finally, inhibition of SHP phosphatase activity by NSC87877 abrogated B. pertussis survival inside murine macrophages. These results reveal that an as yet unknown cAMP-activated signaling pathway controls SHP-1 phosphatase activity and may regulate numerous receptor signaling pathways in leukocytes. Hijacking of SHP-1 by CyaA action then enables B. pertussis to evade NO-mediated killing in sentinel cells of innate immunity.
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Affiliation(s)
- Ondrej Cerny
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Jana Kamanova
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Jiri Masin
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Ilona Bibova
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Karolina Skopova
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
| | - Peter Sebo
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the ASCR, v.v.i., Czech Academy of Sciences, 142 20, Prague 4, Czech Republic
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Karst JC, Ntsogo Enguéné VY, Cannella SE, Subrini O, Hessel A, Debard S, Ladant D, Chenal A. Calcium, acylation, and molecular confinement favor folding of Bordetella pertussis adenylate cyclase CyaA toxin into a monomeric and cytotoxic form. J Biol Chem 2014; 289:30702-30716. [PMID: 25231985 DOI: 10.1074/jbc.m114.580852] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The adenylate cyclase (CyaA) toxin, a multidomain protein of 1706 amino acids, is one of the major virulence factors produced by Bordetella pertussis, the causative agent of whooping cough. CyaA is able to invade eukaryotic target cells in which it produces high levels of cAMP, thus altering the cellular physiology. Although CyaA has been extensively studied by various cellular and molecular approaches, the structural and functional states of the toxin remain poorly characterized. Indeed, CyaA is a large protein and exhibits a pronounced hydrophobic character, making it prone to aggregation into multimeric forms. As a result, CyaA has usually been extracted and stored in denaturing conditions. Here, we define the experimental conditions allowing CyaA folding into a monomeric and functional species. We found that CyaA forms mainly multimers when refolded by dialysis, dilution, or buffer exchange. However, a significant fraction of monomeric, folded protein could be obtained by exploiting molecular confinement on size exclusion chromatography. Folding of CyaA into a monomeric form was found to be critically dependent upon the presence of calcium and post-translational acylation of the protein. We further show that the monomeric preparation displayed hemolytic and cytotoxic activities suggesting that the monomer is the genuine, physiologically active form of the toxin. We hypothesize that the structural role of the post-translational acylation in CyaA folding may apply to other RTX toxins.
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Affiliation(s)
- Johanna C Karst
- Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 28 Rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - V Yvette Ntsogo Enguéné
- Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 28 Rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Sara E Cannella
- Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 28 Rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Orso Subrini
- Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 28 Rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Audrey Hessel
- Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 28 Rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Sylvain Debard
- Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 28 Rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Daniel Ladant
- Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 28 Rue du Dr. Roux, 75724 Paris Cedex 15, France.
| | - Alexandre Chenal
- Institut Pasteur, CNRS UMR 3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 28 Rue du Dr. Roux, 75724 Paris Cedex 15, France.
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Bordetella pertussis adenylate cyclase toxin translocation across a tethered lipid bilayer. Proc Natl Acad Sci U S A 2013; 110:20473-8. [PMID: 24297899 DOI: 10.1073/pnas.1312975110] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Numerous bacterial toxins can cross biological membranes to reach the cytosol of mammalian cells, where they exert their cytotoxic effects. Our model toxin, the adenylate cyclase (CyaA) from Bordetella pertussis, is able to invade eukaryotic cells by translocating its catalytic domain directly across the plasma membrane of target cells. To characterize its original translocation process, we designed an in vitro assay based on a biomimetic membrane model in which a tethered lipid bilayer (tBLM) is assembled on an amine-gold surface derivatized with calmodulin (CaM). The assembled bilayer forms a continuous and protein-impermeable boundary completely separating the underlying calmodulin (trans side) from the medium above (cis side). The binding of CyaA to the tBLM is monitored by surface plasmon resonance (SPR) spectroscopy. CyaA binding to the immobilized CaM, revealed by enzymatic activity, serves as a highly sensitive reporter of toxin translocation across the bilayer. Translocation of the CyaA catalytic domain was found to be strictly dependent on the presence of calcium and also on the application of a negative potential, as shown earlier in eukaryotic cells. Thus, CyaA is able to deliver its catalytic domain across a biological membrane without the need for any eukaryotic components besides CaM. This suggests that the calcium-dependent CyaA translocation may be driven in part by the electrical field across the membrane. This study's in vitro demonstration of toxin translocation across a tBLM provides an opportunity to explore the molecular mechanisms of protein translocation across biological membranes in precisely defined experimental conditions.
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Delivery of large heterologous polypeptides across the cytoplasmic membrane of antigen-presenting cells by the Bordetella RTX hemolysin moiety lacking the adenylyl cyclase domain. Infect Immun 2012; 80:1181-92. [PMID: 22215742 DOI: 10.1128/iai.05711-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The Bordetella adenylate cyclase toxin-hemolysin (CyaA; also called ACT or AC-Hly) targets CD11b-expressing phagocytes and translocates into their cytosol an adenylyl cyclase (AC) that hijacks cellular signaling by conversion of ATP to cyclic AMP (cAMP). Intriguingly, insertion of large passenger peptides removes the enzymatic activity but not the cell-invasive capacity of the AC domain. This has repeatedly been exploited for delivery of heterologous antigens into the cytosolic pathway of CD11b-expressing dendritic cells by CyaA/AC(-) toxoids, thus enabling their processing and presentation on major histocompatibility complex (MHC) class I molecules to cytotoxic CD8(+) T lymphocytes (CTLs). We produced a set of toxoids with overlapping deletions within the first 371 residues of CyaA and showed that the structure of the AC enzyme does not contain any sequences indispensable for its translocation across target cell membrane. Moreover, replacement of the AC domain (residues 1 to 371) with heterologous polypeptides of 40, 146, or 203 residues yielded CyaAΔAC constructs that delivered passenger CTL epitopes into antigen-presenting cells (APCs) and induced strong antigen-specific CD8(+) CTL responses in vivo in mice and ex vivo in human peripheral blood mononuclear cell cultures. This shows that the RTX (repeats in toxin) hemolysin moiety, consisting of residues 374 to 1706 of CyaA, harbors all structural information involved in translocation of the N-terminal AC domain across target cell membranes. These results decipher the extraordinary capacity of the AC domain of CyaA to transport large heterologous cargo polypeptides into the cytosol of CD11b(+) target cells and pave the way for the construction of CyaAΔAC-based polyvalent immunotherapeutic T cell vaccines.
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Role of CD11b/CD18 in the process of intoxication by the adenylate cyclase toxin of Bordetella pertussis. Infect Immun 2011; 80:850-9. [PMID: 22144488 DOI: 10.1128/iai.05979-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The adenylate cyclase toxin (ACT) of Bordetella pertussis does not require a receptor to generate intracellular cyclic AMP (cAMP) in a broad range of cell types. To intoxicate cells, ACT binds to the cell surface, translocates its catalytic domain across the cell membrane, and converts intracellular ATP to cAMP. In cells that express the integrin CD11b/CD18 (CR3), ACT is more potent than in CR3-negative cells. We find, however, that the maximum levels of cAMP accumulation inside CR3-positive and -negative cells are comparable. To better understand how CR3 affects the generation of cAMP, we used Chinese hamster ovary and K562 cells transfected to express CR3 and examined the steps in intoxication in the presence and absence of the integrin. The binding of ACT to cells is greater in CR3-expressing cells at all concentrations of ACT, and translocation of the catalytic domain is enhanced by CR3 expression, with ∼80% of ACT molecules translocating their catalytic domain in CR3-positive cells but only 25% in CR3-negative cells. Once in the cytosol, the unregulated catalytic domain converts ATP to cAMP, and at ACT concentrations >1,000 ng/ml, the intracellular ATP concentration is <5% of that in untreated cells, regardless of CR3 expression. This depletion of ATP prevents further production of cAMP, despite the CR3-mediated enhancement of binding and translocation. In addition to characterizing the effects of CR3 on the actions of ACT, these data show that ATP consumption is yet another concentration-dependent activity of ACT that must be considered when studying how ACT affects target cells.
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Bordetella adenylate cyclase toxin mobilizes its beta2 integrin receptor into lipid rafts to accomplish translocation across target cell membrane in two steps. PLoS Pathog 2010; 6:e1000901. [PMID: 20485565 PMCID: PMC2869314 DOI: 10.1371/journal.ppat.1000901] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 04/07/2010] [Indexed: 12/29/2022] Open
Abstract
Bordetella adenylate cyclase toxin (CyaA) binds the αMβ2 integrin (CD11b/CD18, Mac-1, or CR3) of myeloid phagocytes and delivers into their cytosol an adenylate cyclase (AC) enzyme that converts ATP into the key signaling molecule cAMP. We show that penetration of the AC domain across cell membrane proceeds in two steps. It starts by membrane insertion of a toxin ‘translocation intermediate’, which can be ‘locked’ in the membrane by the 3D1 antibody blocking AC domain translocation. Insertion of the ‘intermediate’ permeabilizes cells for influx of extracellular calcium ions and thus activates calpain-mediated cleavage of the talin tether. Recruitment of the integrin-CyaA complex into lipid rafts follows and the cholesterol-rich lipid environment promotes translocation of the AC domain across cell membrane. AC translocation into cells was inhibited upon raft disruption by cholesterol depletion, or when CyaA mobilization into rafts was blocked by inhibition of talin processing. Furthermore, CyaA mutants unable to mobilize calcium into cells failed to relocate into lipid rafts, and failed to translocate the AC domain across cell membrane, unless rescued by Ca2+ influx promoted in trans by ionomycin or another CyaA protein. Hence, by mobilizing calcium ions into phagocytes, the ‘translocation intermediate’ promotes toxin piggybacking on integrin into lipid rafts and enables AC enzyme delivery into host cytosol. The adenylate cyclase toxin (CyaA) of pathogenic Bordetellae eliminates the first line of host innate immune defense. It penetrates myeloid phagocytes, such as neutrophils, macrophage or dendritic cells, and subverts their signaling by catalyzing an extremely rapid conversion of intracellular ATP to the key signaling molecule cAMP. This efficiently inhibits the oxidative burst and complement-mediated opsonophagocytic killing of bacteria, thus enabling the pathogen to colonize host airways. We show that translocation of CyaA into phagocyte cytosol occurs in two steps. The toxin first binds the integrin CD11b/CD18 and inserts into phagocyte membrane to mediate influx of calcium ions into cells. This promotes relocation of the toxin-receptor complex into specific lipid microdomains within cell membrane called rafts. The increased concentrations of cholesterol within rafts and their particular lipid organization then support translocation of the adenylate cyclase enzyme directly into the cytoplasmic compartment of cells. The mechanism of CyaA penetration into cells sets a new paradigm for membrane translocation of toxins of the RTX family.
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Eby JC, Ciesla WP, Hamman W, Donato GM, Pickles RJ, Hewlett EL, Lencer WI. Selective translocation of the Bordetella pertussis adenylate cyclase toxin across the basolateral membranes of polarized epithelial cells. J Biol Chem 2010; 285:10662-70. [PMID: 20139088 DOI: 10.1074/jbc.m109.089219] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The catalytic domain of Bordetella pertussis adenylate cyclase toxin (ACT) translocates directly across the plasma membrane of mammalian cells to induce toxicity by the production of cAMP. Here, we use electrophysiology to examine the translocation of toxin into polarized epithelial cells that model the mucosal surfaces of the host. We find that both polarized T84 cell monolayers and human airway epithelial cultures respond to nanomolar concentrations of ACT when applied to basolateral membranes, with little or no response to toxin applied apically. The induction of toxicity is rapid and fully explained by increases in intracellular cAMP, consistent with toxin translocation directly across the basolateral membrane. Intoxication of T84 cells occurs in the absence of CD11b/CD18 or evidence of another specific membrane receptor, and it is not dependent on post-translational acylation of the toxin or on host cell membrane potential, both previously reported to be required for toxin action. Thus, elements of the basolateral membrane render epithelial cells highly sensitive to the entry of ACT in the absence of a specific receptor for toxin binding.
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Affiliation(s)
- Joshua C Eby
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
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Martín C, Gómez-Bilbao G, Ostolaza H. Bordetella adenylate cyclase toxin promotes calcium entry into both CD11b+ and CD11b- cells through cAMP-dependent L-type-like calcium channels. J Biol Chem 2009; 285:357-64. [PMID: 19875442 DOI: 10.1074/jbc.m109.003491] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Adenylate cyclase toxin (ACT), a 200 kDa protein, is an essential virulence factor for Bordetella pertussis, the bacterium that causes whooping cough. ACT is a member of the pore-forming RTX (repeats-in-toxin) family of proteins that share a characteristic calcium-binding motif of Gly- and Asp-rich nonapeptide repeats and a marked cytolytic or cytotoxic activity. In addition, ACT exhibits a distinctive feature: it has an N-terminal calmodulin-dependent adenylate cyclase domain. Translocation of this domain into the host cytoplasm results in uncontrolled production of cAMP, and it has classically been assumed that this surge in cAMP is the basis for the toxin-mediated killing. Several members of the RTX family of toxins, including ACT, have been shown to induce intracellular calcium increases, through different mechanisms. We show here that ACT stimulates a raft-mediated calcium influx, through its cAMP production activity, that activates PKA, which in turn activates calcium channels with L-type properties. This process is shown to occur both in CD11b(+) and CD11b(-) cells, suggesting a common mechanism, independent of the toxin receptor. We also show that this ACT-induced calcium influx does not correlate with the toxin-induced cytotoxicity.
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Affiliation(s)
- César Martín
- Unidad de Biofísica, Departamento de Bioquímica, Universidad del País Vasco, Centro Mixto CSIC-UPV/EHU, 48080 Bilbao, Spain
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Fiser R, Konopásek I. Different modes of membrane permeabilization by two RTX toxins: HlyA from Escherichia coli and CyaA from Bordetella pertussis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1249-54. [PMID: 19348784 DOI: 10.1016/j.bbamem.2009.03.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 03/18/2009] [Accepted: 03/29/2009] [Indexed: 11/15/2022]
Abstract
This study clarifies the membrane disruption mechanisms of two bacterial RTX toxins: alphahemolysin (HlyA) from Escherichia coli and a highly homologous adenylate cyclase toxin (CyaA) from Bordetella pertussis. For this purpose, we employed a fluorescence requenching method using liposomes (extruded through filters of different pore size - 1000 nm, 400 nm or 100 nm) with encapsulated fluorescent dye/quencher pair ANTS/DPX. We showed that both toxins induced a graded leakage of liposome content with different selectivities alpha for DPX and ANTS. In contrast to HlyA, CyaA exhibited a higher selectivity for cationic quencher DPX, which increased with vesicle diameter. Large unilamellar vesicles (LUV(1000)) were found to be more suitable for distinguishing between high alpha values whereas smaller ones (LUV(100)) were more appropriate for discriminating an all-or-none leakage (alpha=0) from the graded leakage with low values of alpha. While disrupting LUV(1000), CyaA caused a highly cation-selective leakage (alpha~15) whereas its mutated form with decreased channel K(+)/Cl(-) selectivity due to two substitutions in a predicted transmembrane segment (CyaA-E509K+E516K) exhibited much lower selectivity (alpha approximately 6). We concluded that the fluorescence requenching method in combination with different size of liposomes is a valuable tool for characterization of pore-forming toxins and their variants.
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Affiliation(s)
- Radovan Fiser
- Department of Genetics, Faculty of Science, Charles University in Prague, Vinicná 5, CZ-128 44, Prague 2, Czech Republic.
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Cheung GYC, Kelly SM, Jess TJ, Prior S, Price NC, Parton R, Coote JG. Functional and structural studies on different forms of the adenylate cyclase toxin of Bordetella pertussis. Microb Pathog 2008; 46:36-42. [PMID: 18992319 DOI: 10.1016/j.micpath.2008.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 10/02/2008] [Accepted: 10/07/2008] [Indexed: 12/23/2022]
Abstract
A comparison was made of the cytotoxic activity and secondary structural features of four recombinant forms of adenylate cyclase toxin (CyaA). These forms were fully functional CyaA, CyaA lacking adenylate cyclase enzymatic activity (CyaA*), and non-acylated forms of these toxins, proCyaA and proCyaA*. At a toxin concentration>1 microg/ml, CyaA* was as cytotoxic towards J774.2 cells as CyaA and mediated cell killing at a faster rate than CyaA. At concentrations<0.5 microg/ml, CyaA* was less cytotoxic than CyaA and, at <0.1 microg/ml of CyaA*, no activity was detected. CyaA, but not CyaA*, was able to induce caspase 3/7 activity, a measure of apoptosis. ProCyaA and proCyaA* had no detectable cytotoxic or apoptotic activity. CyaA caused 50% inhibition of the zymosan-stimulated oxidative burst at 0.003 microg/ml, whereas a approximately 500-fold greater toxin concentration of CyaA* or proCyaA was needed for 50% inhibition. ProCyaA* was inactive. CyaA is a calcium-binding protein and far UV circular dichroism (CD), near UV CD and fluorescence spectra analyses showed that all the forms of CyaA had similar overall structures at different calcium concentrations up to 5.0 mM. At 7.5 mM CaCl2, the far UV spectrum of CyaA altered significantly, indicating a change in secondary structure associated with high beta-sheet content or a beta-aggregated state, whereas the spectrum of CyaA* showed only a slight alteration at this calcium concentration. Near UV CD and fluorescence studies were consistent with a rearrangement of secondary structural elements in the presence of CaCl2 for all CyaA forms. There was a marked dependence on protein concentration of the far UV spectra of these CyaA forms, implying an interaction between individual molecules at higher protein concentrations.
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Affiliation(s)
- Gordon Y C Cheung
- Division of Infection and Immunity, University of Glasgow, Institute of Biomedical and Life Sciences, Glasgow Biomedical Research Centre, 120 University Place, Glasgow G12 8TA, UK
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Pyridopyrimidine derivatives as inhibitors of cyclic nucleotide synthesis: Application for treatment of diarrhea. Proc Natl Acad Sci U S A 2008; 105:8440-5. [PMID: 18559851 DOI: 10.1073/pnas.0803096105] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Acute secretory diarrhea induced by infection with enterotoxigenic strains of Escherichia coli involves binding of stable toxin (STa) to its receptor on the intestinal brush border, guanylyl cyclase type C (GC-C). Intracellular cGMP is elevated, inducing increase in chloride efflux and subsequent accumulation of fluid in the intestinal lumen. We have screened a library of compounds and identified a pyridopyrimidine derivatives {5-(3-bromophenyl)-1,3-dimethyl-5,11-dihydro-1H-indeno[2',1':5,6]pyrido[2,3-d]pyrimidine-2,4,6-trione; BPIPP} as an inhibitor of GC-C that can suppress STa-stimulated cGMP accumulation by decreasing GC-C activation in intact T84 human colorectal carcinoma cells. BPIPP inhibited stimulation of guanylyl cyclases, including types A and B and soluble isoform in various cells. BPIPP suppressed stimulation of adenylyl cyclase and significantly decreased the activities of adenylyl cyclase toxin of Bordetella pertussis and edema toxin of Bacillus anthracis. The effects of BPIPP on cyclic nucleotide synthesis were observed only in intact cells. The mechanism of BPIPP-dependent inhibition appears to be complex and indirect, possibly associated with phospholipase C and tyrosine-specific phosphorylation. BPIPP inhibited chloride-ion transport stimulated by activation of guanylyl or adenylyl cyclases and suppressed STa-induced fluid accumulation in an in vivo rabbit intestinal loop model. Thus, BPIPP may be a promising lead compound for treatment of diarrhea and other diseases.
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RTX cytotoxins recognize beta2 integrin receptors through N-linked oligosaccharides. Proc Natl Acad Sci U S A 2008; 105:5355-60. [PMID: 18375764 DOI: 10.1073/pnas.0711400105] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bordetella pertussis adenylate cyclase (AC) toxin-hemolysin (Hly) (CyaA, ACT, or AC-Hly) is a cytotoxin of the RTX (repeat in toxin) family. It delivers into target cells an AC domain that catalyzes uncontrolled conversion of ATP to cAMP, a key signaling molecule subverting phagocyte functions. CyaA utilizes a heavily N-glycosylated beta(2) integrin receptor CD11b/CD18 (alpha(M)beta(2), Mac-1, or CR3). We show that deglycosylation of cell surface proteins by glycosidase treatment, or inhibition of protein N-glycosylation by tunicamycin, ablates CyaA binding and penetration of CD11b-expressing cells. Furthermore, binding of CyaA to cells was strongly inhibited in the presence of free saccharides occurring as building units of integrin oligosaccharide complex, whereas saccharides absent from integrin oligosaccharide chains failed to inhibit CyaA binding to CD11b/CD18-expressing cells. CyaA, hence, selectively recognized sugar residues of N-linked oligosaccharides of integrins. Moreover, glycosylation of CD11a/CD18, another receptor of the beta(2) integrin family, was also essential for cytotoxic action of other RTX cytotoxins, the leukotoxin of Aggregatibacter actinomycetemcomitans (LtxA) and the Escherichia coli alpha-Hly (HlyA). These results show that binding and killing of target cells by CyaA, LtxA, and HlyA depends on recognition of N-linked oligosaccharide chains of beta(2) integrin receptors. This sets a new paradigm for action of RTX cytotoxins.
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Knapp O, Maier E, Mašín J, Šebo P, Benz R. Pore formation by the Bordetella adenylate cyclase toxin in lipid bilayer membranes: Role of voltage and pH. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:260-9. [DOI: 10.1016/j.bbamem.2007.09.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 09/25/2007] [Accepted: 09/27/2007] [Indexed: 11/25/2022]
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Basler M, Knapp O, Masin J, Fiser R, Maier E, Benz R, Sebo P, Osicka R. Segments Crucial for Membrane Translocation and Pore-forming Activity of Bordetella Adenylate Cyclase Toxin. J Biol Chem 2007; 282:12419-29. [PMID: 17347146 DOI: 10.1074/jbc.m611226200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bordetella adenylate cyclase toxin-hemolysin (CyaA, AC-Hly, or ACT) permeabilizes cell membranes by forming small cation-selective (hemolytic) pores and subverts cellular signaling by delivering into host cells an adenylate cyclase (AC) enzyme that converts ATP to cAMP. Both AC delivery and pore formation were previously shown to involve a predicted amphipathic alpha-helix(502-522) containing a pair of negatively charged Glu(509) and Glu(516) residues. Another predicted transmembrane alpha-helix(565-591) comprises a Glu(570) and Glu(581) pair. We examined the roles of these glutamates in the activity of CyaA. Substitutions of Glu(516) increased specific hemolytic activity of CyaA by two different molecular mechanisms. Replacement of Glu(516) by positively charged lysine residue (E516K) increased the propensity of CyaA to form pores, whereas proline (E516P) or glutamine (E516Q) substitutions extended the lifetime of open single pore units. All three substitutions also caused a drop of pore selectivity for cations. Substitutions of Glu(570) and Glu(581) by helix-breaking proline or positively charged lysine residue reduced (E570K, E581P) or ablated (E570P, E581K) AC membrane translocation. Moreover, E570P, E570K, and E581P substitutions down-modulated also the specific hemolytic activity of CyaA. In contrast, the E581K substitution enhanced the hemolytic activity of CyaA 4 times, increasing both the frequency of formation and lifetime of toxin pores. Negative charge at position 570, but not at position 581, was found to be essential for cation selectivity of the pore, suggesting a role of Glu(570) in ion filtering inside or close to pore mouth. The pairs of glutamate residues in the predicted transmembrane segments of CyaA thus appear to play a key functional role in membrane translocation and pore-forming activities of CyaA.
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Affiliation(s)
- Marek Basler
- Institute of Microbiology of the Academy of Sciences of the Czech Republic, Videnska 1083, CZ-142 20 Prague 4, Czech Republic
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Tessier J, Green C, Padgett D, Zhao W, Schwartz L, Hughes M, Hewlett E. Contributions of histamine, prostanoids, and neurokinins to edema elicited by edema toxin from Bacillus anthracis. Infect Immun 2007; 75:1895-903. [PMID: 17261611 PMCID: PMC1865696 DOI: 10.1128/iai.01632-06] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Bacillus anthracis edema toxin (ET), composed of protective antigen and an adenylate cyclase edema factor (EF), elicits edema in host tissues, but the target cells and events leading from EF-mediated cyclic-AMP production to edema are unknown. We evaluated the direct effect of ET on several cell types in vitro and tested the possibility that mediators of vascular leakage, such as histamine, contribute to edema in rabbits given intradermal ET. ET increased the transendothelial electrical resistance of endothelial monolayers, a response that is mechanistically inconsistent with the in vivo vascular leakage induced by ET. Screening of several drugs by intradermal treatment prior to toxin injection demonstrated reduced ET-induced vascular leakage with a cyclo-oxygenase inhibitor (indomethacin), agents that interfere with histamine (pyrilamine or cromolyn), or a neurokinin antagonist (spantide). Systemic administration of indomethacin or celecoxib (cyclo-oxygenase inhibitors), pyrilamine, aprepitant (a neurokinin 1 receptor antagonist), or indomethacin with pyrilamine significantly reduced vascular leakage associated with ET. Although the effects of pyrilamine, cromolyn, or aprepitant on ET-induced vascular leakage suggest a possible role for mast cells (MC) and sensory neurons in ET-induced edema, ET did not elicit degranulation of human skin MC or substance P release from NT2N cells in vitro. Our results indicate that ET, acting indirectly or directly on a target yet to be identified, stimulates the production/release of multiple inflammatory mediators, specifically neurokinins, prostanoids, and histamine. These mediators, individually and through complex interactions, increase vascular permeability, and interventions directed at these mediators may benefit hosts infected with B. anthracis.
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Affiliation(s)
- Jeffrey Tessier
- University of Virginia Health Sciences Center, Box 800419, Charlottesville, VA 22908, USA
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Dal Molin F, Tonello F, Ladant D, Zornetta I, Zamparo I, Di Benedetto G, Zaccolo M, Montecucco C. Cell entry and cAMP imaging of anthrax edema toxin. EMBO J 2006; 25:5405-13. [PMID: 17082768 PMCID: PMC1636612 DOI: 10.1038/sj.emboj.7601408] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2006] [Accepted: 10/05/2006] [Indexed: 02/07/2023] Open
Abstract
The entry and enzymatic activity of the anthrax edema factor (EF) in different cell types was studied by monitoring EF-induced changes in intracellular cAMP with biochemical and microscopic methods. cAMP was imaged in live cells, transfected with a fluorescence resonance energy transfer biosensor based on the protein kinase A regulatory and catalytic subunits fused to CFP and YFP, respectively. The cAMP biosensor was located either in the cytosol or was membrane-bound owing to the addition of a tag determining its myristoylation/palmitoylation. Real-time imaging of cells expressing the cAMP biosensors provided the time course of EF catalytic activity and an indication of its subcellular localization. Bafilomycin A1, an inhibitor of the vacuolar ATPase proton pump, completely prevented EF activity, even when added long after the toxin. The time course of appearance of the adenylate cyclase activity and of bafilomycin A1 action suggests that EF enters the cytosol from late endosomes. EF remains associated to these compartments and its activity shows a perinuclear localization generating intracellular cAMP concentration gradients from the cell centre to the periphery.
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Affiliation(s)
- Federica Dal Molin
- Dipartimento di Scienze Biomediche ed Istituto CNR Neuroscienze, Padova, Italy
| | - Fiorella Tonello
- Dipartimento di Scienze Biomediche ed Istituto CNR Neuroscienze, Padova, Italy
| | - Daniel Ladant
- Departement de Biologie Structurale et Chimie, Institut Pasteur, Paris Cedex, France
| | - Irene Zornetta
- Dipartimento di Scienze Biomediche ed Istituto CNR Neuroscienze, Padova, Italy
| | - Ilaria Zamparo
- Dulbecco Telethon Institute, Padova, Italy
- Istituto Veneto di Medicina Molecolare, Padova, Italy
| | - Giulietta Di Benedetto
- Dulbecco Telethon Institute, Padova, Italy
- Istituto Veneto di Medicina Molecolare, Padova, Italy
| | - Manuela Zaccolo
- Dulbecco Telethon Institute, Padova, Italy
- Istituto Veneto di Medicina Molecolare, Padova, Italy
- These authors share senior authorship
| | - Cesare Montecucco
- Dipartimento di Scienze Biomediche ed Istituto CNR Neuroscienze, Padova, Italy
- These authors share senior authorship
- Dipartimento di Scienze Biomediche, Viale G Colombo 3, 35121 Padova, Italy. Tel.: +39 049 827 6058; Fax: +39 049 827 6049; E-mails: or
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Vojtová J, Kofronová O, Sebo P, Benada O. Bordetella adenylate cyclase toxin induces a cascade of morphological changes of sheep erythrocytes and localizes into clusters in erythrocyte membranes. Microsc Res Tech 2006; 69:119-29. [PMID: 16456835 DOI: 10.1002/jemt.20277] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Adenylate cyclase toxin (CyaA) of Bordetella pertussis penetrates the membrane of eukaryotic cells, producing high levels of intracellular cAMP, as well as hemolysis that results from the formation of cation-selective toxin channels in the membrane. Using several microscopical approaches we studied the effects of CyaA action on the morphology of sheep erythrocytes during early phases preceding lysis and examined localization of CyaA molecules within the erythrocyte membrane. CyaA induced a cascade of morphological changes of erythrocytes, such as shrinkage, formation of membrane projections, and blebs and swelling. The use of an enzymatically inactive CyaA-AC- toxoid that is unable to produce cAMP and of a CyaA-E581K mutant exhibiting higher hemolytic activity than with CyaA showed that the hemolytic activity is responsible for the induction of morphological changes of erythrocytes. Further, immunolabeling of inserted CyaA-232/FLAG molecules with specific anti-FLAG antibodies and IgG-gold particles indicated a clustered distribution of CyaA molecules in erythrocyte membrane. This was confirmed by immunofluorescence and confocal microscopy, which revealed uniform stoichiometry of CyaA clusters, suggesting CyaA binding into specific domains in erythrocyte membrane. Indeed, a decrease of CyaA binding after cholesterol depletion of erythrocytes suggests toxin targeting and binding to membrane microdomains (rafts).
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Affiliation(s)
- Jana Vojtová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20, Prague 4, Czech Republic
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Herrmann M, Schuhmacher A, Mühldorfer I, Melchers K, Prothmann C, Dammeier S. Identification and characterization of secreted effector proteins of Chlamydophila pneumoniae TW183. Res Microbiol 2006; 157:513-24. [PMID: 16797933 DOI: 10.1016/j.resmic.2005.12.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Accepted: 12/20/2005] [Indexed: 11/18/2022]
Abstract
We report the expression of several chlamydial effector proteins in Chlamydophila pneumoniae, as well as their time-dependent secretion into the inclusion membrane. Localization of the respective genes within type III secretion gene clusters as well as bioinformatic analysis suggest that the identified proteins are type III-secreted effector proteins. Immunocytochemistry with antisera raised against CpMip (C. pneumoniae macrophage infectivity potentiator, Cpn0661), Pkn5 (Cpn0703), Cpn0709, Cpn0712 and Cpn0827 showed secretion of the respective proteins into the inclusion membrane at 20 h postinfection (hpi). CpMip was detected within the inclusion membrane from 20 to 72 hpi, whereas Cpn0324 (CopN) was located in this compartment at 72 hpi only. This was confirmed by co-localization of the respective proteins with IncA, an inclusion membrane marker protein. These data illustrate the fact that different effectors are being expressed and secreted during different time intervals of the infection cycle. Proteins Cpn0706 and Cpn0808 were not secreted by C. pneumoniae. The immunophilin FK506, known to inhibit the activity of Legionella, C. trachomatis and C. psittaci Mip proteins, was shown to interfere with chlamydial infection. Here we report the putatively type III-dependent secretion of CpMip into the inclusion membrane as well as the effect of its inhibition on C. pneumoniae infection of HEp-2 cells.
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Affiliation(s)
- Michael Herrmann
- Department of Gastroenterology (RDR/B3), ALTANA Pharma AG, Byk-Gulden Strasse 2, 78467 Konstanz, Germany.
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Mašín J, Konopásek I, Svobodová J, Šebo P. Different structural requirements for adenylate cyclase toxin interactions with erythrocyte and liposome membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004. [DOI: 10.1016/j.bbamem.2003.11.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Matsuzawa T, Fukui A, Kashimoto T, Nagao K, Oka K, Miyake M, Horiguchi Y. Bordetella dermonecrotic toxin undergoes proteolytic processing to be translocated from a dynamin-related endosome into the cytoplasm in an acidification-independent manner. J Biol Chem 2003; 279:2866-72. [PMID: 14597616 DOI: 10.1074/jbc.m310340200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bordetella pertussis dermonecrotic toxin (DNT), which activates intracellular Rho GTPases, is a single chain polypeptide composed of an N-terminal receptor-binding domain and a C-terminal enzymatic domain. We found that DNT was cleaved by furin, a mammalian endoprotease, on the C-terminal side of Arg(44), which generates an N-terminal fragment almost corresponding to the receptor-binding domain and a C-terminal remainder (deltaB) containing the enzymatic domain. These two fragments remained associated even after the cleavage and made a nicked form. DNT mutants insensitive to furin had no cellular effect, whereas the nicked toxin was much more potent than the intact form, indicating that the nicking by furin was a prerequisite for action. DeltaB, but not the nicked toxin, associated with artificial liposomes and activated Rho in cells resistant to DNT because of a lack of surface receptor. These results imply that deltaB, dissociated from the binding domain, fully possesses the ability to enter the cytoplasm across the lipid bilayer membrane. The translocation ability of deltaB was found to be attributable to the N-terminal region encompassing amino acids 45-166, including a putative transmembrane domain. Pharmacological analyses with various reagents disturbing vesicular trafficking revealed that the translocation requires neither the acidification of the endosomes nor retrograde vesicular transport to deeper organelles, although DNT appeared to be internalized via a dynamin-dependent endocytosis. We conclude that DNT binds to its receptor and is internalized into endosomes where the proteolytic processing occurs. DeltaB, liberated from the binding domain after the processing, begins to translocate the enzymatic domain into the cytoplasm.
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Affiliation(s)
- Takeshi Matsuzawa
- Department of Bacterial Toxinology, Research Institute for Microbial Diseases, Osaka University, Yamada-oka 3-1, Suita, Osaka 565-0871, Japan
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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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Rhodes CR, Gray MC, Watson JM, Muratore TL, Kim SB, Hewlett EL, Grisham CM. Structural consequences of divalent metal binding by the adenylyl cyclase toxin of Bordetella pertussis. Arch Biochem Biophys 2001; 395:169-76. [PMID: 11697853 DOI: 10.1006/abbi.2001.2553] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adenylyl cyclase toxin of Bordetella pertussis has been shown by several investigators to require Ca(2+) for its actions on target cells, but little is known about the nature and specificity of divalent metal binding to this novel toxin. Calcium is the preferred divalent metal since toxic actions are markedly reduced in the presence of divalent species other than calcium. Mn(2+) EPR was used to quantitate and characterize divalent metal binding and revealed that the toxin contains approximately 40 divalent metal sites, consisting of at least one class of high-affinity sites that bind Mn(2+) with a K(D) of 0.05 to 0.35 microM and one or more classes of lower affinity sites. Water proton relaxation data indicate that approximately 30 of these sites are completely inaccessible to bulk solvent. Our observations, together with the sequence homology between adenylyl cyclase toxin and the alkaline protease of Pseudomonas aeruginosa, indicate that the formation of five beta-sheet helices within the repeat domain of the toxin upon binding Ca(2+) is required for cell intoxication.
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Affiliation(s)
- C R Rhodes
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22906, USA
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Gupta P, Singh S, Tiwari A, Bhat R, Bhatnagar R. Effect of pH on stability of anthrax lethal factor: correlation between denaturation and activity. Biochem Biophys Res Commun 2001; 284:568-73. [PMID: 11396937 DOI: 10.1006/bbrc.2001.5018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Anthrax is caused by Gram positive bacterium Bacillus anthracis. Pathogenesis is result of production of three protein components, protective antigen (PA), lethal factor (LF), and edema factor (EF). PA in combination with LF (lethal toxin) is lethal to animals, while PA in combination with EF (edema toxin), causes edema. PA, LF, and EF are very thermolabile. Differential scanning calorimetry (DSC) was used to unravel the energetics of LF denaturation as a function of pH ranging from 7.8 to 5.5. Transition temperature (T(m)) of LF was found to be approximately equal to 42 degrees C and onset of denaturation occurs at approximately equal to 30 degrees C. The ratio of calorimetric to van't Hoff's enthalpy was nearly equal to unity at pH 7.0, indicative of presence of single structural domain in LF at pH 7.0, unlike PA which has been structurally observed to consist of 4 domains. It was found by cytotoxicity studies using J774A.1 macrophage like cells that LF was most stable at pH approximately 6.5. This paper reports for the first time the denaturation of LF at different pH values at 37 degrees C and tries to establish a correlation between denaturation and loss of LF activity at different pH values.
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Affiliation(s)
- P Gupta
- Centre for Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
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