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Pérez Vázquez K, Tau J, Leal Denis MF, Fader CM, Ostuni MA, Schwarzbaum PJ, Herlax V. Alpha hemolysin of Escherichia coli induces a necrotic-like procoagulant state in platelets. Biochimie 2024:S0300-9084(24)00137-8. [PMID: 38857695 DOI: 10.1016/j.biochi.2024.06.001] [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: 01/22/2024] [Revised: 06/05/2024] [Accepted: 06/07/2024] [Indexed: 06/12/2024]
Abstract
Uropathogenic strains of E. coli (UPEC) is a leading cause of sepsis, deploying multiple virulence factors to evade host immune responses. Notably, alpha-hemolysin (HlyA) produced by UPEC is implicated in septic symptoms associated with bacteremia, correlating with thrombocytopenia, a critical indicator of organ dysfunction and a predictor of poorer patient prognosis. This study meticulously explores the impact of sublytic concentrations of HlyA on platelets. Findings reveal that HlyA triggers an increase in intracellular calcium, activating calpain and exposing phosphatidylserine to the cell surface, as validated by flow cytometric experiments. Electron microscopy reveals a distinctive balloon-like shape in HlyA-treated platelets, indicative of a procoagulant state. The toxin induces the release of procoagulant extracellular vesicles and the secretion of alpha and dense granules. Overall, the results point to HlyA inducing a necrotic-like procoagulant state in platelets. The effects of sublytic concentrations of HlyA on both erythrocytes and platelets could have a potential impact on capillary microcirculation. Targeting HlyA emerges as a viable therapeutic strategy to mitigate the adverse effects of UPEC infections, especially in South American countries where these infections are endemic, underscoring its significance as a potential therapeutic target.
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Affiliation(s)
- Kenia Pérez Vázquez
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET. Facultad de Ciencias Médicas. Universidad Nacional de La Plata, Argentina
| | - Julia Tau
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET. Facultad de Ciencias Médicas. Universidad Nacional de La Plata, Argentina
| | - M Florencia Leal Denis
- Instituto de Química y Fisicoquímica Biológicas (IQUIFIB) "Prof. Alejandro C. Paladini", Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Claudio M Fader
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología, (IHEM), Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina; Facultad de Odontología, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Mariano A Ostuni
- Université Paris Cité and Université des Antilles, INSERM, BIGR, F-75015, Paris, France
| | - Pablo J Schwarzbaum
- Instituto de Química y Fisicoquímica Biológicas (IQUIFIB) "Prof. Alejandro C. Paladini", Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Vanesa Herlax
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET. Facultad de Ciencias Médicas. Universidad Nacional de La Plata, Argentina.
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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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3
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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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4
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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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Heterologously secreted MbxA from Moraxella bovis induces a membrane blebbing response of the human host cell. Sci Rep 2022; 12:17825. [PMID: 36280777 PMCID: PMC9592583 DOI: 10.1038/s41598-022-22480-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 10/14/2022] [Indexed: 01/20/2023] Open
Abstract
Many proteins of the Repeats in Toxins (RTX) protein family are toxins of Gram-negative pathogens including hemolysin A (HlyA) of uropathogenic E. coli. RTX proteins are secreted via Type I secretion systems (T1SS) and adopt their native conformation in the Ca2+-rich extracellular environment. Here we employed the E. coli HlyA T1SS as a heterologous surrogate system for the RTX toxin MbxA from the bovine pathogen Moraxella bovis. In E. coli the HlyA system successfully activates the heterologous MbxA substrate by acylation and secretes the precursor proMbxA and active MbxA allowing purification of both species in quantities sufficient for a variety of investigations. The activating E. coli acyltransferase HlyC recognizes the acylation sites in MbxA, but unexpectedly in a different acylation pattern as for its endogenous substrate HlyA. HlyC-activated MbxA shows host species-independent activity including a so-far unknown toxicity against human lymphocytes and epithelial cells. Using live-cell imaging, we show an immediate MbxA-mediated permeabilization and a rapidly developing blebbing of the plasma membrane in epithelial cells, which is associated with immediate cell death.
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Goldsmith JA, DiVenere AM, Maynard JA, McLellan JS. Structural basis for non-canonical integrin engagement by Bordetella adenylate cyclase toxin. Cell Rep 2022; 40:111196. [PMID: 35977491 PMCID: PMC9416875 DOI: 10.1016/j.celrep.2022.111196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 06/08/2022] [Accepted: 07/20/2022] [Indexed: 11/29/2022] Open
Abstract
Integrins are ubiquitous cell-surface heterodimers that are exploited by pathogens and toxins, including leukotoxins that target β2 integrins on phagocytes. The Bordetella adenylate cyclase toxin (ACT) uses the αMβ2 integrin as a receptor, but the structural basis for integrin binding and neutralization by antibodies is poorly understood. Here, we use cryoelectron microscopy to determine a 2.7 Å resolution structure of an ACT fragment bound to αMβ2. This structure reveals that ACT interacts with the headpiece and calf-2 of the αM subunit in a non-canonical manner specific to bent, inactive αMβ2. Neutralizing antibody epitopes map to ACT residues involved in αM binding, providing the basis for antibody-mediated attachment inhibition. Furthermore, binding to αMβ2 positions the essential ACT acylation sites, which are conserved among toxins exported by type I secretion systems, at the cell membrane. These findings reveal a structural mechanism for integrin-mediated attachment and explain antibody-mediated neutralization of ACT intoxication.
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Affiliation(s)
- Jory A Goldsmith
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Andrea M DiVenere
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jennifer A Maynard
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
| | - Jason S McLellan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA.
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Sasaki H, Ueshiba H, Yanagisawa N, Itoh Y, Ishikawa H, Shigenaga A, Benga L, Ike F. Genomic and pathogenic characterization of RTX toxin producing Rodentibacter sp. that is closely related to Rodentibacter haemolyticus. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2022; 102:105314. [PMID: 35675867 DOI: 10.1016/j.meegid.2022.105314] [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: 03/13/2022] [Revised: 05/26/2022] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
Rodentibacter spp. are opportunistic pathogens that are often isolated from the upper respiratory tracts of laboratory rodents. In particular, R. pneumotropicus and R. heylii require considerable caution in rodent colonies, as they cause lethal pneumonia in rodents. A new species, R. haemolyticus, has recently been classified in the genus, and a very closely related strain, Rodentibacter sp. strain JRC, has been isolated in Japan. This study focused on strain JRC by performing genomic and pathogenic analyses. Draft genome sequencing of strain JRC identified several genes coding for putative virulent proteins, including hemolysin and adhesin. Furthermore, we found a new RTX (repeats-in-structural toxin) toxin gene in the genome, which was predicted to produce a critical virulence factor (RTXIA) similar to Enterobacteriaceae. The concentrated culture supernatant containing RTX toxin (RTXIA) showed cytotoxicity toward RAW264.7 cells. Pre-incubation with anti-CD11a attenuated the cytolysis, suggesting that the concentrated culture supernatant containing RTXIA is cell surface LFA-1 mediated cytolysin. Experimental infection of strain JRC intranasally with 5 female BALB/c-Rag2-/- mice showed 60% lethality and was not significantly different from those of R. pneumotropicus ATCC 35149T using the log-rank test. Combined with our finding that RTXIA has an almost identical amino acid sequence (98% identity) to that of R. haemolyticus 1625/19T, these results strongly suggest that RTXIA-producing strain JRC (and related R. haemolyticus) is pathogenic to immunodeficient rodents, and both agents should be excluded in laboratory rodent colonies.
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Affiliation(s)
- Hiraku Sasaki
- Department of Health Science, Faculty of Health and Sports Science, Juntendo University, Inzai, Chiba, Japan.
| | - Hidehiro Ueshiba
- Department of Microbiology and Immunology, Tokyo Women's Medical University School of Medicine, Shinjuku, Tokyo, Japan
| | - Naoko Yanagisawa
- Department of Microbiology and Immunology, Tokyo Women's Medical University School of Medicine, Shinjuku, Tokyo, Japan
| | - Yuta Itoh
- Department of Health Science, Faculty of Health and Sports Science, Juntendo University, Inzai, Chiba, Japan
| | - Hiroki Ishikawa
- Department of Microbiology and Immunology, Showa University School of Medicine, Shinagawa, Tokyo, Japan
| | - Ayako Shigenaga
- Institute of Health and Sports Science & Medicine, Graduate School of Health and Sports Science, Juntendo University, Inzai, Chiba, Japan
| | - Laurentiu Benga
- Central Unit for Animal Research and Animal Welfare Affairs, University Hospital, Heinrich - Heine - University, Düsseldorf, Germany
| | - Fumio Ike
- Experimental Animal Division, RIKEN BioResource Research Center, Tsukuba, Ibaraki, Japan
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Klimova N, Holubova J, Streparola G, Tomala J, Brazdilova L, Stanek O, Bumba L, Sebo P. Pertussis toxin suppresses dendritic cell-mediated delivery of B. pertussis into lung-draining lymph nodes. PLoS Pathog 2022; 18:e1010577. [PMID: 35666769 PMCID: PMC9216613 DOI: 10.1371/journal.ppat.1010577] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 06/22/2022] [Accepted: 05/08/2022] [Indexed: 11/18/2022] Open
Abstract
The adenylate cyclase (ACT) and the pertussis (PT) toxins of Bordetella pertussis exert potent immunomodulatory activities that synergize to suppress host defense in the course of whooping cough pathogenesis. We compared the mouse lung infection capacities of B. pertussis (Bp) mutants (Bp AC− or Bp PT–) producing enzymatically inactive toxoids and confirm that ACT action is required for maximal bacterial proliferation in the first days of infection, whereas PT action is crucial for persistence of B. pertussis in mouse lungs. Despite accelerated and near complete clearance from the lungs by day 14 of infection, the PT− bacteria accumulated within the lymphoid tissue of lung-draining mediastinal lymph nodes (mLNs). In contrast, the wild type or AC− bacteria colonized the lungs but did not enter into mLNs. Lung infection by the PT− mutant triggered an early arrival of migratory conventional dendritic cells with associated bacteria into mLNs, where the PT− bacteria entered the T cell-rich paracortex of mLNs by day 5 and proliferated in clusters within the B-cell zone (cortex) of mLNs by day 14, being eventually phagocytosed by infiltrating neutrophils. Finally, only infection by the PT− bacteria triggered an early production of anti-B. pertussis serum IgG antibodies already within 14 days of infection. These results reveal that action of the pertussis toxin blocks DC-mediated delivery of B. pertussis bacteria into mLNs and prevents bacterial colonization of mLNs, thus hampering early adaptive immune response to B. pertussis infection. Of the three classical Bordetella species causing respiratory infections in mammals, only the human-specialized whooping cough agent B. pertussis produces the pertussis toxin (PT) as its major virulence factor. Human pertussis is an acute respiratory illness and the pleiotropic activities of pertussis toxin account for the characteristic systemic manifestations of the disease, such as hyperleukocytosis, histamine sensitization, hyperinsulinemia, or inflammatory lung pathology. We found that PT activity inhibits the migration of infected dendritic cells from the lungs into the draining mediastinal lymph nodes (mLNs). This prevents mLN infection by bacteria evading from migratory cells and delivery of bacterial antigens into mLNs. As a result, the induction of adaptive serum antibody responses to infection is delayed. We thus propose that PT action serves to create a time window for proliferation of B. pertussis on airway mucosa to facilitate transmission of the pathogen among humans.
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Affiliation(s)
- Nela Klimova
- Institute of Microbiology of the Czech Academy of Sciences,Prague, Czech Republic
- Faculty of Sciences, Charles University, Prague, Czech Republic
| | - Jana Holubova
- Institute of Microbiology of the Czech Academy of Sciences,Prague, Czech Republic
| | - Gaia Streparola
- Institute of Microbiology of the Czech Academy of Sciences,Prague, Czech Republic
- Czech Centre for Phenogenomics BIOCEV, Vestec, Czech Republic
| | - Jakub Tomala
- Institute of Microbiology of the Czech Academy of Sciences,Prague, Czech Republic
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Ludmila Brazdilova
- Institute of Microbiology of the Czech Academy of Sciences,Prague, Czech Republic
- Faculty of Sciences, Charles University, Prague, Czech Republic
| | - Ondrej Stanek
- 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
- * E-mail: (LB); (PS)
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences,Prague, Czech Republic
- * E-mail: (LB); (PS)
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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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11
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Holubova J, Juhasz A, Masin J, Stanek O, Jurnecka D, Osickova A, Sebo P, Osicka R. Selective Enhancement of the Cell-Permeabilizing Activity of Adenylate Cyclase Toxin Does Not Increase Virulence of Bordetella pertussis. Int J Mol Sci 2021; 22:ijms222111655. [PMID: 34769101 PMCID: PMC8583748 DOI: 10.3390/ijms222111655] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/18/2021] [Accepted: 10/26/2021] [Indexed: 01/15/2023] Open
Abstract
The whooping cough agent, Bordetella pertussis, secretes an adenylate cyclase toxin–hemolysin (CyaA, ACT, or AC-Hly) that catalyzes the conversion of intracellular ATP to cAMP and through its signaling annihilates the bactericidal activities of host sentinel phagocytes. In parallel, CyaA permeabilizes host cells by the formation of cation-selective membrane pores that account for the hemolytic activity of CyaA. The pore-forming activity contributes to the overall cytotoxic effect of CyaA in vitro, and it has previously been proposed to synergize with the cAMP-elevating activity in conferring full virulence on B. pertussis in the mouse model of pneumonic infection. CyaA primarily targets myeloid phagocytes through binding of their complement receptor 3 (CR3, integrin αMβ2, or CD11b/CD18). However, with a reduced efficacy, the toxin can promiscuously penetrate and permeabilize the cell membrane of a variety of non-myeloid cells that lack CR3 on the cell surface, including airway epithelial cells or erythrocytes, and detectably intoxicates them by cAMP. Here, we used CyaA variants with strongly and selectively enhanced or reduced pore-forming activity that, at the same time, exhibited a full capacity to elevate cAMP concentrations in both CR3-expressing and CR3-non-expressing target cells. Using B. pertussis mutants secreting such CyaA variants, we show that a selective enhancement of the cell-permeabilizing activity of CyaA does not increase the overall virulence and lethality of pneumonic B. pertussis infection of mice any further. In turn, a reduction of the cell-permeabilizing activity of CyaA did not reduce B. pertussis virulence any importantly. These results suggest that the phagocyte-paralyzing cAMP-elevating capacity of CyaA prevails over the cell-permeabilizing activity of CyaA that appears to play an auxiliary role in the biological activity of the CyaA toxin in the course of B. pertussis infections in vivo.
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Affiliation(s)
- Jana Holubova
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic; (J.H.); (A.J.); (J.M.); (O.S.); (D.J.); (A.O.); (P.S.)
| | - Attila Juhasz
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic; (J.H.); (A.J.); (J.M.); (O.S.); (D.J.); (A.O.); (P.S.)
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Jiri Masin
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic; (J.H.); (A.J.); (J.M.); (O.S.); (D.J.); (A.O.); (P.S.)
| | - Ondrej Stanek
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic; (J.H.); (A.J.); (J.M.); (O.S.); (D.J.); (A.O.); (P.S.)
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic; (J.H.); (A.J.); (J.M.); (O.S.); (D.J.); (A.O.); (P.S.)
| | - Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic; (J.H.); (A.J.); (J.M.); (O.S.); (D.J.); (A.O.); (P.S.)
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic; (J.H.); (A.J.); (J.M.); (O.S.); (D.J.); (A.O.); (P.S.)
| | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic; (J.H.); (A.J.); (J.M.); (O.S.); (D.J.); (A.O.); (P.S.)
- Correspondence: ; Tel.: +420-241-062-770
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12
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Sora VM, Meroni G, Martino PA, Soggiu A, Bonizzi L, Zecconi A. Extraintestinal Pathogenic Escherichia coli: Virulence Factors and Antibiotic Resistance. Pathogens 2021; 10:pathogens10111355. [PMID: 34832511 PMCID: PMC8618662 DOI: 10.3390/pathogens10111355] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/05/2021] [Accepted: 10/18/2021] [Indexed: 12/29/2022] Open
Abstract
The One Health approach emphasizes the importance of antimicrobial resistance (AMR) as a major concern both in public health and in food animal production systems. As a general classification, E. coli can be distinguished based on the ability to cause infection of the gastrointestinal system (IPEC) or outside of it (ExPEC). Among the different pathogens, E. coli are becoming of great importance, and it has been suggested that ExPEC may harbor resistance genes that may be transferred to pathogenic or opportunistic bacteria. ExPEC strains are versatile bacteria that can cause urinary tract, bloodstream, prostate, and other infections at non-intestinal sites. In this context of rapidly increasing multidrug-resistance worldwide and a diminishingly effective antimicrobial arsenal to tackle resistant strains. ExPEC infections are now a serious public health threat worldwide. However, the clinical and economic impact of these infections and their optimal management are challenging, and consequently, there is an increasing awareness of the importance of ExPECs amongst healthcare professionals and the general public alike. This review aims to describe pathotype characteristics of ExPEC to increase our knowledge of these bacteria and, consequently, to increase our chances to control them and reduce the risk for AMR, following a One Health approach.
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13
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Lepesheva A, Osickova A, Holubova J, Jurnecka D, Knoblochova S, Espinosa-Vinals C, Bumba L, Skopova K, Fiser R, Osicka R, Sebo P, Masin J. Different roles of conserved tyrosine residues of the acylated domains in folding and activity of RTX toxins. Sci Rep 2021; 11:19814. [PMID: 34615931 PMCID: PMC8494930 DOI: 10.1038/s41598-021-99112-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/17/2021] [Indexed: 12/31/2022] Open
Abstract
Pore-forming repeats in toxins (RTX) are key virulence factors of many Gram-negative pathogens. We have recently shown that the aromatic side chain of the conserved tyrosine residue 940 within the acylated segment of the RTX adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) plays a key role in target cell membrane interaction of the toxin. Therefore, we used a truncated CyaA-derived RTX719 construct to analyze the impact of Y940 substitutions on functional folding of the acylated segment of CyaA. Size exclusion chromatography combined with CD spectroscopy revealed that replacement of the aromatic side chain of Y940 by the side chains of alanine or proline residues disrupted the calcium-dependent folding of RTX719 and led to self-aggregation of the otherwise soluble and monomeric protein. Intriguingly, corresponding alanine substitutions of the conserved Y642, Y643 and Y639 residues in the homologous RtxA, HlyA and ApxIA hemolysins from Kingella kingae, Escherichia coli and Actinobacillus pleuropneumoniae, affected the membrane insertion, pore-forming (hemolytic) and cytotoxic capacities of these toxins only marginally. Activities of these toxins were impaired only upon replacement of the conserved tyrosines by proline residues. It appears, hence, that the critical role of the aromatic side chain of the Y940 residue is highly specific for the functional folding of the acylated domain of CyaA and determines its capacity to penetrate target cell membrane.
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Affiliation(s)
- Anna Lepesheva
- 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
| | - Jana Holubova
- 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
| | | | - Ladislav Bumba
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Karolina Skopova
- 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
| | - 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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14
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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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15
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Espinosa-Vinals CA, Masin J, Holubova J, Stanek O, Jurnecka D, Osicka R, Sebo P, Bumba L. Almost half of the RTX domain is dispensable for complement receptor 3 binding and cell-invasive activity of the Bordetella adenylate cyclase toxin. J Biol Chem 2021; 297:100833. [PMID: 34051233 PMCID: PMC8214218 DOI: 10.1016/j.jbc.2021.100833] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 01/20/2023] Open
Abstract
The whooping cough agent Bordetella pertussis secretes an adenylate cyclase toxin (CyaA) that through its large carboxy-proximal Repeat-in-ToXin (RTX) domain binds the complement receptor 3 (CR3). The RTX domain consists of five blocks (I-V) of characteristic glycine and aspartate-rich nonapeptides that fold into five Ca2+-loaded parallel β-rolls. Previous work indicated that the CR3-binding structure comprises the interface of β-rolls II and III. To test if further portions of the RTX domain contribute to CR3 binding, we generated a construct with the RTX block II/III interface (CyaA residues 1132-1294) linked directly to the C-terminal block V fragment bearing the folding scaffold (CyaA residues 1562-1681). Despite deletion of 267 internal residues of the RTX domain, the Ca2+-driven folding of the hybrid block III/V β-roll still supported formation of the CR3-binding structure at the interface of β-rolls II and III. Moreover, upon stabilization by N- and C-terminal flanking segments, the block III/V hybrid-comprising constructs competed with CyaA for CR3 binding and induced formation of CyaA toxin-neutralizing antibodies in mice. Finally, a truncated CyaAΔ1295-1561 toxin bound and penetrated erythrocytes and CR3-expressing cells, showing that the deleted portions of RTX blocks III, IV, and V (residues 1295-1561) were dispensable for CR3 binding and for toxin translocation across the target cell membrane. This suggests that almost a half of the RTX domain of CyaA is not involved in target cell interaction and rather serves the purpose of toxin secretion.
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Affiliation(s)
- Carlos Angel Espinosa-Vinals
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic; University of Chemistry and Technology, Prague, Prague, Czech Republic
| | - Jiri Masin
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jana Holubova
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Ondrej Stanek
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - David Jurnecka
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
| | - Ladislav Bumba
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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16
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Li SC, Cheng YT, Wang CY, Wu JY, Chen ZW, Wang JP, Lin JH, Hsuan SL. Actinobacillus pleuropneumoniae exotoxin ApxI induces cell death via attenuation of FAK through LFA-1. Sci Rep 2021; 11:1753. [PMID: 33462305 PMCID: PMC7813829 DOI: 10.1038/s41598-021-81290-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 01/05/2021] [Indexed: 01/15/2023] Open
Abstract
ApxI exotoxin is an important virulence factor derived from Actinobacillus pleuropneumoniae that causes pleuropneumonia in swine. Here, we investigate the role of lymphocyte function-associated antigen 1 (LFA-1, CD11a/CD18), a member of the β2 integrin family, and the involvement of the integrin signaling molecules focal adhesion kinase (FAK) and Akt in ApxI cytotoxicity. Using Western blot analysis, we found that ApxI downregulated the activity of FAK and Akt in porcine alveolar macrophages (AMs). Preincubation of porcine AMs with an antibody specific for porcine CD18 reduced ApxI-induced cytotoxicity as measured by a lactate dehydrogenase release assay and decreased ApxI-induced FAK and Akt attenuation, as shown by Western blot analysis. Pretreatment with the chemical compounds PMA and SC79, which activate FAK and Akt, respectively, failed to overcome the ApxI-induced attenuation of FAK and Akt and death of porcine AMs. Notably, the transfection experiments revealed that ectopic expression of porcine LFA-1 (pLFA-1) conferred susceptibility to ApxI in ApxI-insensitive cell lines, including human embryonic kidney 293T cells and FAK-deficient mouse embryonic fibroblasts (MEFs). Furthermore, ectopic expression of FAK significantly reduced ApxI cytotoxicity in pLFA-1-cotransfected FAK-deficient MEFs. These findings show for the first time that pLFA-1 renders cells susceptible to ApxI and ApxI-mediated attenuation of FAK activity via CD18, thereby contributing to subsequent cell death.
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Affiliation(s)
- Siou-Cen Li
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, Taichung City, 402, Taiwan.,Animal Technology Laboratories, Agricultural Technology Research Institute, Hsinchu City, 300, Taiwan
| | - Yu-Tsen Cheng
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, Taichung City, 402, Taiwan
| | - Ching-Yang Wang
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, Taichung City, 402, Taiwan
| | - Jia-Ying Wu
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, Taichung City, 402, Taiwan
| | - Zeng-Weng Chen
- Animal Technology Laboratories, Agricultural Technology Research Institute, Hsinchu City, 300, Taiwan
| | - Jyh-Perng Wang
- Animal Technology Laboratories, Agricultural Technology Research Institute, Hsinchu City, 300, Taiwan
| | - Jiunn-Horng Lin
- Animal Technology Laboratories, Agricultural Technology Research Institute, Hsinchu City, 300, Taiwan
| | - Shih-Ling Hsuan
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, Taichung City, 402, Taiwan.
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17
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Bianchi M, Sivarajan R, Walles T, Hackenberg S, Steinke M. Susceptibility of primary human airway epithelial cells to Bordetella pertussis adenylate cyclase toxin in two- and three-dimensional culture conditions. Innate Immun 2020; 27:89-98. [PMID: 33317363 PMCID: PMC7780358 DOI: 10.1177/1753425920979354] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The human pathogen Bordetella pertussis targets the respiratory epithelium and causes whooping cough. Its virulence factor adenylate cyclase toxin (CyaA) plays an important role in the course of infection. Previous studies on the impact of CyaA on human epithelial cells have been carried out using cell lines derived from the airways or the intestinal tract. Here, we investigated the interaction of CyaA and its enzymatically inactive but fully pore-forming toxoid CyaA-AC– with primary human airway epithelial cells (hAEC) derived from different anatomical sites (nose and tracheo-bronchial region) in two-dimensional culture conditions. To assess possible differences between the response of primary hAEC and respiratory cell lines directly, we included HBEC3-KT in our studies. In comparative analyses, we studied the impact of both the toxin and the toxoid on cell viability, intracellular cAMP concentration and IL-6 secretion. We found that the selected hAEC, which lack CD11b, were differentially susceptible to both CyaA and CyaA-AC–. HBEC3-KT appeared not to be suitable for subsequent analyses. Since the nasal epithelium first gets in contact with airborne pathogens, we further studied the effect of CyaA and its toxoid on the innate immunity of three-dimensional tissue models of the human nasal mucosa. The present study reveals first insights in toxin–cell interaction using primary hAEC.
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Affiliation(s)
- Maria Bianchi
- Chair of Tissue Engineering and Regenerative Medicine, University Hospital Würzburg, Germany
| | - Rinu Sivarajan
- Chair of Tissue Engineering and Regenerative Medicine, University Hospital Würzburg, Germany
| | - Thorsten Walles
- Department of Thoracic Surgery, University Medicine Magdeburg, Germany
| | - Stephan Hackenberg
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, University Hospital Würzburg, Germany
| | - Maria Steinke
- Chair of Tissue Engineering and Regenerative Medicine, University Hospital Würzburg, Germany
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18
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Binding of Kingella kingae RtxA Toxin Depends on Cell Surface Oligosaccharides, but Not on β 2 Integrins. Int J Mol Sci 2020; 21:ijms21239092. [PMID: 33260488 PMCID: PMC7730106 DOI: 10.3390/ijms21239092] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/24/2020] [Accepted: 11/27/2020] [Indexed: 11/29/2022] Open
Abstract
The Gram-negative coccobacillus Kingella kingae is increasingly recognized as an important invasive pediatric pathogen that causes mostly bacteremia and skeletal system infections. K. kingae secretes an RtxA toxin that belongs to a broad family of the RTX (Repeats in ToXin) cytotoxins produced by bacterial pathogens. Recently, we demonstrated that membrane cholesterol facilitates interaction of RtxA with target cells, but other cell surface structures potentially involved in toxin binding to cells remain unknown. We show that deglycosylation of cell surface structures by glycosidase treatment, or inhibition of protein N- and O-glycosylation by chemical inhibitors substantially reduces RtxA binding to target cells. Consequently, the deglycosylated cells were more resistant to cytotoxic activity of RtxA. Moreover, experiments on cells expressing or lacking cell surface integrins of the β2 family revealed that, unlike some other cytotoxins of the RTX family, K. kingae RtxA does not bind target cells via the β2 integrins. Our results, hence, show that RtxA binds cell surface oligosaccharides present on all mammalian cells but not the leukocyte-restricted β2 integrins. This explains the previously observed interaction of the toxin with a broad range of cell types of various mammalian species and reveals that RtxA belongs to the group of broadly cytolytic RTX hemolysins.
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19
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Motlova L, Klimova N, Fiser R, Sebo P, Bumba L. Continuous Assembly of β-Roll Structures Is Implicated in the Type I-Dependent Secretion of Large Repeat-in-Toxins (RTX) Proteins. J Mol Biol 2020; 432:5696-5710. [PMID: 32860773 DOI: 10.1016/j.jmb.2020.08.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/22/2020] [Accepted: 08/24/2020] [Indexed: 01/10/2023]
Abstract
Repeats-in-Toxin (RTX) proteins of Gram-negative bacteria are excreted through the type I secretion system (T1SS) that recognizes non-cleavable C-terminal secretion signals. These are preceded by arrays of glycine and aspartate-rich nonapeptide repeats grouped by four to eight β strands into blocks that fold into calcium-binding parallel β-roll structures. The β-rolls are interspersed by linkers of variable length and sequence and the organization of multiple RTX repeat blocks within large RTX domains remains unknown. Here we examined the structure and function of the RTX domain of Bordetella pertussis adenylate cyclase toxin (CyaA) that is composed of five β-roll RTX blocks. We show that the non-folded RTX repeats maintain the stability of the CyaA polypeptide in the Ca2+-depleted bacterial cytosol and thereby enable its efficient translocation through the T1SS apparatus. The efficacy of secretion of truncated CyaA constructs was dictated by the number of retained RTX repeat blocks and depended on the presence of extracellular Ca2+ ions. We further describe the crystal structure of the RTX blocks IV-V of CyaA (CyaA1372-1681) that consists of a contiguous assembly of two β-rolls that differs substantially from the arrangement of the RTX blocks observed in RTX lipases or other RTX proteins. These results provide a novel structural insight into the architecture of the RTX domains of large RTX proteins and support the "push-ratchet" mechanism of the T1SS-mediated secretion of very large RTX proteins.
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Affiliation(s)
- Lucia Motlova
- Faculty of Sciences, Charles University, Vinicna 5, 128 44 Prague 2, Czech Republic
| | - Nela Klimova
- Faculty of Sciences, Charles University, Vinicna 5, 128 44 Prague 2, Czech Republic.; Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
| | - Radovan Fiser
- Faculty of Sciences, Charles University, Vinicna 5, 128 44 Prague 2, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
| | - Ladislav Bumba
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic..
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20
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Krueger E, Brown AC. Aggregatibacter actinomycetemcomitans leukotoxin: From mechanism to targeted anti-toxin therapeutics. Mol Oral Microbiol 2020; 35:85-105. [PMID: 32061022 PMCID: PMC7359886 DOI: 10.1111/omi.12284] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 12/13/2022]
Abstract
Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium associated with localized aggressive periodontitis, as well as other systemic diseases. This organism produces a number of virulence factors, all of which provide some advantage to the bacterium. Several studies have demonstrated that clinical isolates from diseased patients, particularly those of African descent, frequently belong to specific clones of A. actinomycetemcomitans that produce significantly higher amounts of a protein exotoxin belonging to the repeats-in-toxin (RTX) family, leukotoxin (LtxA), whereas isolates from healthy patients harbor minimally leukotoxic strains. This finding suggests that LtxA might play a key role in A. actinomycetemcomitans pathogenicity. Because of this correlation, much work over the past 30 years has been focused on understanding the mechanisms by which LtxA interacts with and kills host cells. In this article, we review those findings, highlight the remaining open questions, and demonstrate how knowledge of these mechanisms, particularly the toxin's interactions with lymphocyte function-associated antigen-1 (LFA-1) and cholesterol, enables the design of targeted anti-LtxA strategies to prevent/treat disease.
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Affiliation(s)
- Eric Krueger
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Angela C. Brown
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA 18015, USA
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21
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Osickova A, Khaliq H, Masin J, Jurnecka D, Sukova A, Fiser R, Holubova J, Stanek O, Sebo P, Osicka R. Acyltransferase-mediated selection of the length of the fatty acyl chain and of the acylation site governs activation of bacterial RTX toxins. J Biol Chem 2020; 295:9268-9280. [PMID: 32461253 DOI: 10.1074/jbc.ra120.014122] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/20/2020] [Indexed: 11/06/2022] Open
Abstract
In a wide range of organisms, from bacteria to humans, numerous proteins have to be posttranslationally acylated to become biologically active. Bacterial repeats in toxin (RTX) cytolysins form a prominent group of proteins that are synthesized as inactive protoxins and undergo posttranslational acylation on ε-amino groups of two internal conserved lysine residues by co-expressed toxin-activating acyltransferases. Here, we investigated how the chemical nature, position, and number of bound acyl chains govern the activities of Bordetella pertussis adenylate cyclase toxin (CyaA), Escherichia coli α-hemolysin (HlyA), and Kingella kingae cytotoxin (RtxA). We found that the three protoxins are acylated in the same E. coli cell background by each of the CyaC, HlyC, and RtxC acyltransferases. We also noted that the acyltransferase selects from the bacterial pool of acyl-acyl carrier proteins (ACPs) an acyl chain of a specific length for covalent linkage to the protoxin. The acyltransferase also selects whether both or only one of two conserved lysine residues of the protoxin will be posttranslationally acylated. Functional assays revealed that RtxA has to be modified by 14-carbon fatty acyl chains to be biologically active, that HlyA remains active also when modified by 16-carbon acyl chains, and that CyaA is activated exclusively by 16-carbon acyl chains. These results suggest that the RTX toxin molecules are structurally adapted to the length of the acyl chains used for modification of their acylated lysine residue in the second, more conserved acylation site.
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Affiliation(s)
- Adriana Osickova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Humaira Khaliq
- 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
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Anna Sukova
- 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
| | - Jana Holubova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ondrej Stanek
- 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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22
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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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24
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Galle JN, Hegemann JH. Exofacial phospholipids at the plasma membrane: ill-defined targets for early infection processes. Biol Chem 2020; 400:1323-1334. [PMID: 31408428 DOI: 10.1515/hsz-2019-0187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 08/06/2019] [Indexed: 02/04/2023]
Abstract
The eukaryotic plasma membrane (PM) consists largely of phospholipids and proteins, and separates the intracellular compartments from the extracellular space. It also serves as a signaling platform for cell-to-cell communication and an interaction platform for the molecular crosstalk between pathogens and their target cells. Much research has been done to elucidate the interactions between pathogens and host membrane proteins. However, little is known about the interactions between pathogens and membrane phospholipids, although reports have described a contribution of phospholipids to cell recognition and/or invasion during early infection by diverse pathogens. Thus, during adhesion to the host cell, the obligate intracellular bacterial pathogens Chlamydia spp., the facultative intracellular pathogen Helicobacter pylori and the facultative aerobic pathogen Vibrio parahaemolyticus, interact with exofacial phospholipids. This review focuses on several prominent instances of pathogen interaction with host-cell phospholipids.
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Affiliation(s)
- Jan N Galle
- Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Johannes H Hegemann
- Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
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25
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RTX Toxins Ambush Immunity's First Cellular Responders. Toxins (Basel) 2019; 11:toxins11120720. [PMID: 31835552 PMCID: PMC6950748 DOI: 10.3390/toxins11120720] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/05/2019] [Accepted: 12/07/2019] [Indexed: 01/17/2023] Open
Abstract
The repeats-in-toxin (RTX) family represents a unique class of bacterial exoproteins. The first family members described were toxins from Gram-negative bacterial pathogens; however, additional members included exoproteins with diverse functions. Our review focuses on well-characterized RTX family toxins from Aggregatibacteractinomycetemcomitans (LtxA), Mannheimiahaemolytica (LktA), Bordetella pertussis (CyaA), uropathogenic Escherichia coli (HlyA), and Actinobacillus pleuropneumoniae (ApxIIIA), as well as the studies that have honed in on a single host cell receptor for RTX toxin interactions, the β2 integrins. The β2 integrin family is composed of heterodimeric members with four unique alpha subunits and a single beta subunit. β2 integrins are only found on leukocytes, including neutrophils and monocytes, the first responders to inflammation following bacterial infection. The LtxA, LktA, HlyA, and ApxIIIA toxins target the shared beta subunit, thereby targeting all types of leukocytes. Specific β2 integrin family domains are required for the RTX toxin’s cytotoxic activity and are summarized here. Research examining the domains of the RTX toxins required for cytotoxic and hemolytic activity is also summarized. RTX toxins attack and kill phagocytic immune cells expressing a single integrin family, providing an obvious advantage to the pathogen. The critical question that remains, can the specificity of the RTX-β2 integrin interaction be therapeutically targeted?
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26
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Bordetella Adenylate Cyclase Toxin Inhibits Monocyte-to-Macrophage Transition and Dedifferentiates Human Alveolar Macrophages into Monocyte-like Cells. mBio 2019; 10:mBio.01743-19. [PMID: 31551332 PMCID: PMC6759761 DOI: 10.1128/mbio.01743-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Monocytes arriving at the site of infection differentiate into functional effector macrophages to replenish the resident sentinel cells. Bordetella pertussis, the pertussis agent, secretes an adenylate cyclase toxin-hemolysin (CyaA) that binds myeloid phagocytes through complement receptor 3 (CD11b/CD18) and swiftly delivers its adenylyl cyclase enzyme domain into phagocytes. This ablates the bactericidal capacities of phagocytes through massive and unregulated conversion of cytosolic ATP into the key signaling molecule cAMP. We show that exposure of primary human monocytes to as low a concentration as 22.5 pM CyaA, or a low (2:1) multiplicity of infection by CyaA-producing B. pertussis bacteria, blocks macrophage colony-stimulating factor (M-CSF)-driven differentiation of monocytes. CyaA-induced cAMP signaling mediated through the activity of protein kinase A (PKA) efficiently blocked expression of macrophage markers, and the monocytes exposed to 22.5 pM CyaA failed to acquire the characteristic intracellular complexity of mature macrophage cells. Neither M-CSF-induced endoplasmic reticulum (ER) expansion nor accumulation of Golgi bodies, mitochondria, or lysosomes was observed in toxin-exposed monocytes, which remained small and poorly phagocytic and lacked pseudopodia. Exposure to 22.5 pM CyaA toxin provoked loss of macrophage marker expression on in vitro differentiated macrophages, as well as on primary human alveolar macrophages, which appeared to dedifferentiate into monocyte-like cells with upregulated CD14 levels. This is the first report that terminally differentiated tissue-resident macrophage cells can be dedifferentiated in vitro The results suggest that blocking of monocyte-to-macrophage transition and/or dedifferentiation of the sentinel cells of innate immunity through cAMP-elevating toxin action may represent a novel immune evasion strategy of bacterial pathogens.IMPORTANCE Macrophages are key sentinel cells of the immune system, and, as such, they are targeted by the toxins produced by the pertussis agent Bordetella pertussis The adenylate cyclase toxin (CyaA) mediates immune evasion of B. pertussis by suspending the bactericidal activities of myeloid phagocytes. We reveal a novel mechanism of potential subversion of host immunity, where CyaA at very low (22 pM) concentrations could inhibit maturation of human monocyte precursors into the more phagocytic macrophage cells. Furthermore, exposure to low CyaA amounts has been shown to trigger dedifferentiation of mature primary human alveolar macrophages back into monocyte-like cells. This unprecedented capacity is likely to promote survival of the pathogen in the airways, both by preventing maturation of monocytes attracted to the site of infection into phagocytic macrophages and by dedifferentiation of the already airway-resident sentinel cells.
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Vega BA, Belinka BA, Kachlany SC. Aggregatibacter actinomycetemcomitans Leukotoxin (LtxA; Leukothera ®): Mechanisms of Action and Therapeutic Applications. Toxins (Basel) 2019; 11:toxins11090489. [PMID: 31454891 PMCID: PMC6784247 DOI: 10.3390/toxins11090489] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/21/2019] [Accepted: 08/22/2019] [Indexed: 12/18/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans is an oral pathogen that produces the RTX toxin, leukotoxin (LtxA; Leukothera®). A. actinomycetemcomitans is strongly associated with the development of localized aggressive periodontitis. LtxA acts as a virulence factor for A. actinomycetemcomitans to subvert the host immune response by binding to the β2 integrin lymphocyte function-associated antigen-1 (LFA-1; CD11a/CD18) on white blood cells (WBCs), causing cell death. In this paper, we reviewed the state of knowledge on LtxA interaction with WBCs and the subsequent mechanisms of induced cell death. Finally, we touched on the potential therapeutic applications of LtxA (trade name Leukothera®) toxin therapy for the treatment of hematological malignancies and immune-mediated diseases.
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Affiliation(s)
- Brian A Vega
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ 07103, USA
- Actinobac Biomed, Inc., Princeton, NJ 08540, USA
| | | | - Scott C Kachlany
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ 07103, USA.
- Actinobac Biomed, Inc., Princeton, NJ 08540, USA.
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28
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The Extracellular Domain of the β 2 Integrin β Subunit (CD18) Is Sufficient for Escherichia coli Hemolysin and Aggregatibacter actinomycetemcomitans Leukotoxin Cytotoxic Activity. mBio 2019; 10:mBio.01459-19. [PMID: 31289186 PMCID: PMC6747720 DOI: 10.1128/mbio.01459-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Urinary tract infections are one of the most common bacterial infections worldwide. Uropathogenic Escherichia coli strains are responsible for more than 80% of community-acquired urinary tract infections. Although we have known for nearly a century that severe infections stemming from urinary tract infections, including kidney or bloodstream infections are associated with expression of a toxin, hemolysin, from uropathogenic Escherichia coli, how hemolysin functions to enhance virulence is unknown. Our research defines the interaction of hemolysin with the β2 integrin, a human white cell adhesion molecule, as a potential therapeutic target during urinary tract infections. The E. coli hemolysin is the prototype for a toxin family (RTX family) produced by a wide array of human and animal pathogens. Our work extends to the identification and characterization of the receptor for an additional member of the RTX family, suggesting that this interaction may be broadly conserved throughout the RTX toxin family. The Escherichia coli hemolysin (HlyA) is a pore-forming exotoxin associated with severe complications of human urinary tract infections. HlyA is the prototype of the repeats-in-toxin (RTX) family, which includes LtxA from Aggregatibacter actinomycetemcomitans, a periodontal pathogen. The existence and requirement for a host cell receptor for these toxins are controversial. We performed an unbiased forward genetic selection in a mutant library of human monocytic cells, U-937, for host factors involved in HlyA cytotoxicity. The top candidate was the β2 integrin β subunit. Δβ2 cell lines are approximately 100-fold more resistant than wild-type U-937 cells to HlyA, but remain sensitive to HlyA at high concentrations. Similarly, Δβ2 cells are more resistant than wild-type U-937 cells to LtxA, as Δβ2 cells remain LtxA resistant even at >1,000-fold-higher concentrations of the toxin. Loss of any single β2 integrin α subunit, or even all four α subunits together, does not confer resistance to HlyA. HlyA and LtxA bind to the β2 subunit, but not to αL, αM, or αX in far-Western blots. Genetic complementation of Δβ2 cells with either β2 or β2 with a cytoplasmic tail deletion restores HlyA and LtxA sensitivity, suggesting that β2 integrin signaling is not required for cytotoxicity. Finally, β2 mutations do not alter sensitivity to unrelated pore-forming toxins, as wild-type or Δβ2 cells are equally sensitive to Staphylococcus aureus α-toxin and Proteus mirabilis HpmA. Our studies show two RTX toxins use the β2 integrin β subunit alone to facilitate cytotoxicity, but downstream integrin signaling is dispensable.
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29
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Nigorikawa K, Matsumura T, Sakamoto H, Morioka S, Kofuji S, Takasuga S, Hazeki K. Sac1 Phosphoinositide Phosphatase Regulates Foam Cell Formation by Modulating SR-A Expression in Macrophages. Biol Pharm Bull 2019; 42:923-928. [DOI: 10.1248/bpb.b18-00907] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kiyomi Nigorikawa
- Graduate School of Biomedical & Health Sciences, Hiroshima University
| | - Takuma Matsumura
- Graduate School of Biomedical & Health Sciences, Hiroshima University
| | - Hiromi Sakamoto
- Graduate School of Biomedical & Health Sciences, Hiroshima University
| | - Shin Morioka
- Graduate School of Biomedical & Health Sciences, Hiroshima University
| | - Satoshi Kofuji
- Graduate School of Biomedical & Health Sciences, Hiroshima University
| | - Shunsuke Takasuga
- Department of Pathology and Immunology, Akita University School of Medicine
| | - Kaoru Hazeki
- Graduate School of Biomedical & Health Sciences, Hiroshima University
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30
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Roderova J, Osickova A, Sukova A, Mikusova G, Fiser R, Sebo P, Osicka R, Masin J. Residues 529 to 549 participate in membrane penetration and pore-forming activity of the Bordetella adenylate cyclase toxin. Sci Rep 2019; 9:5758. [PMID: 30962483 PMCID: PMC6453906 DOI: 10.1038/s41598-019-42200-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 03/27/2019] [Indexed: 11/30/2022] Open
Abstract
The adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) of pathogenic Bordetellae delivers its adenylyl cyclase (AC) enzyme domain into the cytosol of host cells and catalyzes uncontrolled conversion of cellular ATP to cAMP. In parallel, the toxin forms small cation-selective pores that permeabilize target cell membrane and account for the hemolytic activity of CyaA on erythrocytes. The pore-forming domain of CyaA is predicted to consist of five transmembrane α-helices, of which the helices I, III, IV and V have previously been characterized. We examined here the α-helix II that is predicted to form between residues 529 to 549. Substitution of the glycine 531 residue by a proline selectively reduced the hemolytic capacity but did not affect the AC translocating activity of the CyaA-G531P toxin. In contrast, CyaA toxins with alanine 538 or 546 replaced by diverse residues were selectively impaired in the capacity to translocate the AC domain across cell membrane but remained fully hemolytic. Such toxins, however, formed pores in planar asolectin bilayer membranes with a very low frequency and with at least two different conducting states. The helix-breaking substitution of alanine 538 by a proline residue abolished the voltage-activated increase of membrane activity of CyaA in asolectin bilayers. These results reveal that the predicted α-helix comprising the residues 529 to 549 plays a key role in CyaA penetration into the target plasma membrane and pore-forming activity of the toxin.
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Affiliation(s)
- Jana Roderova
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic
| | - Anna Sukova
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic
| | - Gabriela Mikusova
- Charles University, Department of Genetics and Microbiology, Faculty of Science, Vinicna 5, 128 43, Prague, Czech Republic
| | - Radovan Fiser
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic.,Charles University, Department of Genetics and Microbiology, Faculty of Science, Vinicna 5, 128 43, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic
| | - Jiri Masin
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20, Prague, Czech Republic.
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31
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Krueger E, Hayes S, Chang EH, Yutuc S, Brown AC. Receptor-Based Peptides for Inhibition of Leukotoxin Activity. ACS Infect Dis 2018; 4:1073-1081. [PMID: 29742342 DOI: 10.1021/acsinfecdis.7b00230] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The Gram-negative bacterium Aggregatibacter actinomycetemcomitans, commonly associated with localized aggressive periodontitis (LAP), secretes an RTX (repeats-in-toxin) protein leukotoxin (LtxA) that targets human white blood cells, an interaction that is driven by its recognition of the lymphocyte function-associated antigen-1 (LFA-1) integrin. In this study, we report on the inhibition of LtxA-LFA-1 binding as an antivirulence strategy to inhibit LtxA-mediated cytotoxicity. Specifically, we designed and synthesized peptides corresponding to the reported LtxA binding domain on LFA-1 and characterized their capability to inhibit LtxA binding to LFA-1 and subsequent cytotoxic activity in human immune cells. We found that several of these peptides, corresponding to sequential β-strands in the LtxA-binding domain of LFA-1, inhibit LtxA activity, demonstrating the effectiveness of this approach. Further investigations into the mechanism by which these peptides inhibit LtxA binding to LFA-1 reveal a correlation between toxin-peptide affinity and LtxA-mediated cytotoxicity, leading to a diminished association between LtxA and LFA-1 on the cell membrane. Our results demonstrate the possibility of using target-based peptides to inhibit LtxA activity, and we expect that a similar approach could be used to hinder the activity of other RTX toxins.
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Affiliation(s)
- Eric Krueger
- Department of Chemical and Biomolecular Engineering, Lehigh University, Iacocca Hall, Room B323, 111 Research Drive, Bethlehem, Pennsylvania 18015, United States
| | - Shannon Hayes
- Department of Chemical and Biomolecular Engineering, Lehigh University, Iacocca Hall, Room B323, 111 Research Drive, Bethlehem, Pennsylvania 18015, United States
| | - En Hyung Chang
- Department of Chemical and Biomolecular Engineering, Lehigh University, Iacocca Hall, Room B323, 111 Research Drive, Bethlehem, Pennsylvania 18015, United States
| | - Shailagne Yutuc
- Department of Chemical and Biomolecular Engineering, Lehigh University, Iacocca Hall, Room B323, 111 Research Drive, Bethlehem, Pennsylvania 18015, United States
| | - Angela C. Brown
- Department of Chemical and Biomolecular Engineering, Lehigh University, Iacocca Hall, Room B323, 111 Research Drive, Bethlehem, Pennsylvania 18015, United States
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Bordetella Pertussis Adenylate Cyclase Toxin Does Not Possess a Phospholipase A Activity; Serine 606 and Aspartate 1079 Residues Are Not Involved in Target Cell Delivery of the Adenylyl Cyclase Enzyme Domain. Toxins (Basel) 2018; 10:toxins10060245. [PMID: 29914160 PMCID: PMC6024677 DOI: 10.3390/toxins10060245] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 12/02/2022] Open
Abstract
The adenylate cyclase toxin-hemolysin (CyaA, ACT, or AC-Hly) plays a crucial role in virulence and airway colonization capacity of the whooping cough agent Bordetella pertussis. The toxin penetrates target cell membranes and exhibits three distinct biological activities. A population of CyaA conformers forms small cation-selective pores that permeabilize the cell membrane for potassium efflux, which can provoke colloid-osmotic (oncotic) cell lysis. The other two activities are due to CyaA conformers that transiently form calcium influx conduits in the target cell membrane and translocate the adenylate cyclase (AC) enzyme into cytosol of cells. A fourth putative biological activity has recently been reported; an intrinsic phospholipase A (PLA) activity was claimed to be associated with the CyaA polypeptide and be involved in the mechanism of translocation of the AC enzyme polypeptide across cell membrane lipid bilayer. However, the conclusions drawn by the authors contradicted their own results and we show them to be erroneous. We demonstrate that highly purified CyaA is devoid of any detectable phospholipase A1 activity and that contrary to the published claims, the two putative conserved phospholipase A catalytic residues, namely the Ser606 and Asp1079 residues, are not involved in the process of membrane translocation of the AC domain of CyaA across target membranes.
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33
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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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34
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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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The conserved tyrosine residue 940 plays a key structural role in membrane interaction of Bordetella adenylate cyclase toxin. Sci Rep 2017; 7:9330. [PMID: 28839199 PMCID: PMC5571180 DOI: 10.1038/s41598-017-09575-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 07/27/2017] [Indexed: 02/03/2023] Open
Abstract
The adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) translocates its adenylate cyclase (AC) enzyme domain into target cells in a step that depends on membrane cholesterol content. We thus examined what role in toxin activities is played by the five putative cholesterol recognition amino acid consensus (CRAC) motifs predicted in CyaA hemolysin moiety. CRAC-disrupting phenylalanine substitutions had no impact on toxin activities and these were not inhibited by free cholesterol, showing that the putative CRAC motifs are not involved in cholesterol binding. However, helix-breaking proline substitutions in these segments uncovered a structural role of the Y632, Y658, Y725 and Y738 residues in AC domain delivery and pore formation by CyaA. Substitutions of Y940 of the fifth motif, conserved in the acylated domains of related RTX toxins, did not impact on fatty-acylation of CyaA by CyaC and the CyaA-Y940F mutant was intact for toxin activities on erythrocytes and myeloid cells. However, the Y940A or Y940P substitutions disrupted the capacity of CyaA to insert into artificial lipid bilayers or target cell membranes. The aromatic ring of tyrosine 940 side chain thus appears to play a key structural role in molecular interactions that initiate CyaA penetration into target membranes.
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Morioka S, Nigorikawa K, Hazeki K, Ohmura M, Sakamoto H, Matsumura T, Takasuga S, Hazeki O. Phosphoinositide phosphatase Sac3 regulates the cell surface expression of scavenger receptor A and formation of lipid droplets in macrophages. Exp Cell Res 2017; 357:252-259. [DOI: 10.1016/j.yexcr.2017.05.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/12/2017] [Accepted: 05/23/2017] [Indexed: 11/25/2022]
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Abstract
Escherichia coli are a common cause of infectious disease outside of the gastrointestinal tract. Several independently evolved E. coli clades are common causes of urinary tract and bloodstream infections. There is ample epidemiological and in vitro evidence that several different protein toxins common to many, but not all, of these strains are likely to aid the colonization and immune-evasion ability of these bacteria. This review discusses our current knowledge and areas of ignorance concerning the contribution of the hemolysin; cytotoxic-necrotizing factor-1; and the autotransporters, Sat, Pic, and Vat, to extraintestinal human disease.
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Cyclic AMP-Elevating Capacity of Adenylate Cyclase Toxin-Hemolysin Is Sufficient for Lung Infection but Not for Full Virulence of Bordetella pertussis. Infect Immun 2017; 85:IAI.00937-16. [PMID: 28396322 DOI: 10.1128/iai.00937-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 04/02/2017] [Indexed: 02/05/2023] Open
Abstract
The adenylate cyclase toxin-hemolysin (CyaA, ACT, or AC-Hly) of Bordetella pertussis targets phagocytic cells expressing the complement receptor 3 (CR3, Mac-1, αMβ2 integrin, or CD11b/CD18). CyaA delivers into cells an N-terminal adenylyl cyclase (AC) enzyme domain that is activated by cytosolic calmodulin and catalyzes unregulated conversion of cellular ATP into cyclic AMP (cAMP), a key second messenger subverting bactericidal activities of phagocytes. In parallel, the hemolysin (Hly) moiety of CyaA forms cation-selective hemolytic pores that permeabilize target cell membranes. We constructed the first B. pertussis mutant secreting a CyaA toxin having an intact capacity to deliver the AC enzyme into CD11b-expressing (CD11b+) host phagocytes but impaired in formation of cell-permeabilizing pores and defective in cAMP elevation in CD11b- cells. The nonhemolytic AC+ Hly- bacteria inhibited the antigen-presenting capacities of coincubated mouse dendritic cells in vitro and skewed their Toll-like receptor (TLR)-triggered maturation toward a tolerogenic phenotype. The AC+ Hly- mutant also infected mouse lungs as efficiently as the parental AC+ Hly+ strain. Hence, elevation of cAMP in CD11b- cells and/or the pore-forming capacity of CyaA were not required for infection of mouse airways. The latter activities were, however, involved in bacterial penetration across the epithelial layer, enhanced neutrophil influx into lung parenchyma during sublethal infections, and the exacerbated lung pathology and lethality of B. pertussis infections at higher inoculation doses (>107 CFU/mouse). The pore-forming activity of CyaA further synergized with the cAMP-elevating activity in downregulation of major histocompatibility complex class II (MHC-II) molecules on infiltrating myeloid cells, likely contributing to immune subversion of host defenses by the whooping cough agent.
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Sasaki H, Ishikawa H, Terayama H, Asano R, Kawamoto E, Ishibashi H, Boot R. Identification of a virulence determinant that is conserved in the Jawetz and Heyl biotypes of [Pasteurella] pneumotropica. Pathog Dis 2016; 74:ftw066. [PMID: 27402782 DOI: 10.1093/femspd/ftw066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2016] [Indexed: 11/12/2022] Open
Abstract
[Pasteurella] pneumotropica is a ubiquitous bacterium frequently isolated from laboratory rodents. Although this bacterium causes various diseases in immunosuppressed animals, little is known about major virulence factors and their roles in pathogenicity. To identify virulence factors, we sequenced the genome of [P.] pneumotropica biotype Heyl strain ATCC 12555, and compared the resulting non-contiguous draft genome sequence with the genome of biotype Jawetz strain ATCC 35149. Among a large number of genes encoding virulence-associated factors in both strains, four genes encoding for YadA-like proteins, which are known virulence factors that function in host cell adherence and invasion in many pathogens. In this study, we assessed YadA distribution and biological activity as an example of one of virulence-associated factor shared, with biotype Jawetz and Heyl. More than half of mouse isolates were found to have at least one of these genes; whereas, the majority of rat isolates did not. Autoagglutination activity, and ability to bind to mouse collagen type IV and mouse fibroblast cells, was significantly higher in YadA-positive than YadA-negative strains. To conclude, we identified a large number of candidate genes predicted to influence [P.] pneumotropica pathogenesis.
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Affiliation(s)
- Hiraku Sasaki
- Department of Health Science, School of Health and Sports Science, Juntendo University, 1-1 Hiraga-gakuendai, Inzai, Chiba 270-1695, Japan
| | - Hiroki Ishikawa
- Department of Microbiology and Immunology, Showa University School of Medicine, 1-5-8 Hatanodai, Tokyo 142-8555, Japan
| | - Hayato Terayama
- Department of Anatomy, Division of Basic Medical Science, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Ryoki Asano
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, 41-438 Kaidobata-Nishi, Shimoshinjo-Nakano, Akita 010-0195, Japan
| | - Eiichi Kawamoto
- Animal Research Center, Tokyo Medical University, 6-1-1 Shinjuku, Tokyo 160-8402, Japan
| | - Hidetoshi Ishibashi
- Animal Research Center, Tokyo Medical University, 6-1-1 Shinjuku, Tokyo 160-8402, Japan
| | - Ron Boot
- National Institute of Public Health and the Environment, Antonie van Leeuwenhoeklaan 9 3721 MA Bilthoven, the Netherlands
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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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Osicka R, Osickova A, Hasan S, Bumba L, Cerny J, Sebo P. Bordetella adenylate cyclase toxin is a unique ligand of the integrin complement receptor 3. eLife 2015; 4:e10766. [PMID: 26650353 PMCID: PMC4755762 DOI: 10.7554/elife.10766] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 12/09/2015] [Indexed: 12/24/2022] Open
Abstract
Integrins are heterodimeric cell surface adhesion and signaling receptors that are essential for metazoan existence. Some integrins contain an I-domain that is a major ligand binding site. The ligands preferentially engage the active forms of the integrins and trigger signaling cascades that alter numerous cell functions. Here we found that the adenylate cyclase toxin (CyaA), a key virulence factor of the whooping cough agent Bordetella pertussis, preferentially binds an inactive form of the integrin complement receptor 3 (CR3), using a site outside of its I-domain. CyaA binding did not trigger downstream signaling of CR3 in human monocytes and CyaA-catalyzed elevation of cAMP effectively blocked CR3 signaling initiated by a natural ligand. This unprecedented type of integrin-ligand interaction distinguishes CyaA from all other known ligands of the I-domain-containing integrins and provides a mechanistic insight into the previously observed central role of CyaA in the pathogenesis of B. pertussis.
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Affiliation(s)
- Radim Osicka
- 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.,Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Shakir Hasan
- 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
| | - Jiri Cerny
- Institute of Biotechnology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
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Eby JC, Hoffman CL, Gonyar LA, Hewlett EL. Review of the neutrophil response to Bordetella pertussis infection. Pathog Dis 2015; 73:ftv081. [PMID: 26432818 DOI: 10.1093/femspd/ftv081] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2015] [Indexed: 01/13/2023] Open
Abstract
The nature and timing of the neutrophil response to infection with Bordetella pertussis is influenced by multiple virulence factors expressed by the bacterium. After inoculation of the host airway, the recruitment of neutrophils signaled by B. pertussis lipooligosaccharide (LOS) is suppressed by pertussis toxin (PTX). Over the next week, the combined activities of PTX, LOS and adenylate cyclase toxin (ACT) result in production of cytokines that generate an IL-17 response, promoting neutrophil recruitment which peaks at 10-14 days after inoculation in mice. Arriving at the site of infection, neutrophils encounter the powerful local inhibitory activity of ACT, in conjunction with filamentous hemagglutinin. With the help of antibodies, neutrophils contribute to clearance of B. pertussis, but only after 28-35 days in a naïve mouse. Studies of the lasting, antigen-specific IL-17 response to infection in mice and baboons has led to progress in vaccine development and understanding of pathogenesis. Questions remain about the mediators that coordinate neutrophil recruitment and the mechanisms by which neutrophils overcome B. pertussis virulence factors.
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Affiliation(s)
- Joshua C Eby
- Division of Infectious Diseases, University of Virginia, Charlottesville, VA 22908, USA
| | - Casandra L Hoffman
- Division of Infectious Diseases, University of Virginia, Charlottesville, VA 22908, USA
| | - Laura A Gonyar
- Division of Infectious Diseases, University of Virginia, Charlottesville, VA 22908, USA
| | - Erik L Hewlett
- Division of Infectious Diseases, University of Virginia, Charlottesville, VA 22908, USA
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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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Ristow LC, Welch RA. Hemolysin of uropathogenic Escherichia coli: A cloak or a dagger? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:538-45. [PMID: 26299820 DOI: 10.1016/j.bbamem.2015.08.015] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/05/2015] [Accepted: 08/18/2015] [Indexed: 01/27/2023]
Abstract
Hemolysin from uropathogenic Escherichia coli (UPEC) is a hemolytic and cytotoxic protein active against a broad range of species and cell types. Expression of hemolysin correlates with severity of infection, as up to 78% of UPEC isolates from pyelonephritis cases express hemolysin. Despite decades of research on hemolysin activity, the mechanism of intoxication and the function of hemolysin in UPEC infection remain elusive. Early in vitro research established the role of hemolysin as a lytic protein at high doses. It is hypothesized that hemolysin is secreted at sublytic doses in vivo and recent research has focused on understanding the more subtle effects of hemolysin both in vitro and in elegant infection models in vivo, including inoculation by micropuncture of individual kidney nephrons. As the field continues to evolve, comparisons of hemolysin function in isolates from a range of UTI infections will be important for delineating the role of this toxin. 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)
- Laura C Ristow
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Rodney A Welch
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA.
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45
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Hasan S, Osickova A, Bumba L, Novák P, Sebo P, Osicka R. Interaction of Bordetella
adenylate cyclase toxin with complement receptor 3 involves multivalent glycan binding. FEBS Lett 2014; 589:374-9. [DOI: 10.1016/j.febslet.2014.12.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/24/2014] [Accepted: 12/17/2014] [Indexed: 10/24/2022]
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Monoclonal antibodies against Vibrio vulnificus RtxA1 elicit protective immunity through distinct mechanisms. Infect Immun 2014; 82:4813-23. [PMID: 25156730 DOI: 10.1128/iai.02130-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Vibrio vulnificus causes rapidly progressing septicemia with an extremely high mortality rate (≥50%), even with aggressive antibiotic treatment. The bacteria secrete multifunctional autoprocessing repeats-in-toxin (MARTX) toxins, which are involved in the pathogenesis of Gram-negative Vibrio species. Recently, we reported that immunization with the C-terminal region of V. vulnificus RtxA1/MARTXVv, RtxA1-C, elicits a protective immune response against V. vulnificus through a poorly defined mechanism. In this study, we generated a panel of new monoclonal antibodies (MAbs) against V. vulnificus RtxA1-C and investigated their protective efficacies and mechanisms in a mouse model of infection. Prophylactic administration of seven MAbs strongly protected mice against lethal V. vulnificus infection (more than 90% survival). Moreover, three of these MAbs (21RA, 24RA, and 47RA) demonstrated marked efficacy as postexposure therapy. Notably, 21RA was therapeutically effective against lethal V. vulnificus infection by a variety of routes. Using Fab fragments and a neutropenic mouse model, we showed that 21RA and 24RA mediate protection from V. vulnificus infection through an Fc-independent and/or neutrophil-independent pathway. In contrast, 47RA-mediated protection was dependent on its Fc region and was reduced to 50% in neutropenic mice compared with 21RA-mediated and 24RA-mediated protection. Bacteriological study indicated that 21RA appears to enhance the clearance of V. vulnificus from the blood. Overall, these studies suggest that humoral immunity controls V. vulnificus infection through at least two different mechanisms. Furthermore, our panel of MAbs could provide attractive candidates for the further development of immunoprophylaxis/therapeutics and other therapies against V. vulnificus that target the MARTX toxin.
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47
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Sebo P, Osicka R, Masin J. Adenylate cyclase toxin-hemolysin relevance for pertussis vaccines. Expert Rev Vaccines 2014; 13:1215-27. [PMID: 25090574 DOI: 10.1586/14760584.2014.944900] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The adenylate cyclase toxin-hemolysin (ACT, AC-Hly or CyaA) is a key virulence factor of Bordetella pertussis. It targets bactericidal activities of phagocytes, such as oxidative burst and complement- or antibody-mediated opsonophagocytic killing of bacteria. Through cAMP signaling, CyaA also skews TLR-triggered maturation of dendritic cells, inhibiting proinflammatory IL-12 and TNF-α secretion and enhancing IL-10 production and Treg expansion, likely hampering induction of adaptive immune responses to Bordetella infections. Non-enzymatic CyaA toxoid is a potent protective antigen and adjuvant that boosts immunogenicity of co-administered B. pertussis antigens and improves potency of acellular pertussis (aP) vaccines in mice. This makes CyaA a prime antigen candidate for inclusion into a next generation of aP vaccines. Moreover, recombinant CyaA toxoids were recently shown to be safe in humans in frame of Phase I clinical evaluation of a CyaA-based immunotherapeutic vaccine that induces Th1-polarized CD8(+) cytotoxic T-lymphocyte responses targeting cervical tumors.
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Affiliation(s)
- Peter Sebo
- Institute of Microbiology, Academy of Sciences of the Czech Republic, v.v.i, Videnska 1083, 142 20, Prague 4, Czech Republic
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48
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Skals M, Bjaelde RG, Reinholdt J, Poulsen K, Vad BS, Otzen DE, Leipziger J, Praetorius HA. Bacterial RTX toxins allow acute ATP release from human erythrocytes directly through the toxin pore. J Biol Chem 2014; 289:19098-109. [PMID: 24860098 DOI: 10.1074/jbc.m114.571414] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
ATP is as an extracellular signaling molecule able to amplify the cell lysis inflicted by certain bacterial toxins including the two RTX toxins α-hemolysin (HlyA) from Escherichia coli and leukotoxin A (LtxA) from Aggregatibacter actinomycetemcomitans. Inhibition of P2X receptors completely blocks the RTX toxin-induced hemolysis over a larger concentration range. It is, however, at present not known how the ATP that provides the amplification is released from the attacked cells. Here we show that both HlyA and LtxA trigger acute release of ATP from human erythrocytes that preceded and were not caused by cell lysis. This early ATP release did not occur via previously described ATP-release pathways in the erythrocyte. Both HlyA and LtxA were capable of triggering ATP release in the presence of the pannexin 1 blockers carbenoxolone and probenecid, and the HlyA-induced ATP release was found to be similar in erythrocytes from pannexin 1 wild type and knock-out mice. Moreover, the voltage-dependent anion channel antagonist TRO19622 had no effect on ATP release by either of the toxins. Finally, we showed that both HlyA and LtxA were able to release ATP from ATP-loaded lipid (1-palmitoyl-2-oleoyl-phosphatidylcholine) vesicles devoid of any erythrocyte channels or transporters. Again we were able to show that this happened in a non-lytic fashion, using calcein-containing vesicles as controls. These data show that both toxins incorporate into lipid vesicles and allow ATP to be released. We suggest that both toxins cause acute ATP release by letting ATP pass the toxin pores in both human erythrocytes and artificial membranes.
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Affiliation(s)
| | | | | | | | - Brian S Vad
- the Department of Molecular Biology and Genetics, Interdisciplinary Nanoscience Center (iNANO), Center for Insoluble Proteins (inSPIN), Aarhus University, Aarhus C 8000, Denmark
| | - Daniel E Otzen
- the Department of Molecular Biology and Genetics, Interdisciplinary Nanoscience Center (iNANO), Center for Insoluble Proteins (inSPIN), Aarhus University, Aarhus C 8000, Denmark
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Sialic acid residues are essential for cell lysis mediated by leukotoxin from Aggregatibacter actinomycetemcomitans. Infect Immun 2014; 82:2219-28. [PMID: 24643533 DOI: 10.1128/iai.01647-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Leukotoxin (LtxA) from Aggregatibacter actinomycetemcomitans is known to target and lyse β2-integrin-expressing cells such as polymorphonuclear leukocytes and macrophages. LtxA is an important virulence factor that facilitates chronic inflammation and is strongly associated with a fast-progressing form of periodontitis caused by the JP2 clone of the bacterium. Here, we show that sialic acid residues are important for LtxA-induced cell lysis, regardless of whether the cell express β2-integrin or not. Clearly, removal of sialic acid groups significantly reduces a β2-integrin-specific LtxA-induced lysis. Moreover, sialic acid presented on alternative proteins, such as, for instance, on erythrocytes that do not express β2-integrin, also makes the cells more sensitive to LtxA. The data also illustrate the importance of the negative charge in order for the sialic acid to associate LtxA with the membrane. Removal of sialic acid is in itself sufficient to significantly reduce the negative charge on the erythrocytes. Moreover, we found that on human erythrocytes there is a positive association between the sensitivity to LtxA and the amount of negative charge caused by sialic acid. Interestingly, these features are not shared by all RTX toxins, since α-hemolysin from Escherichia coli induced cell lysis of both β2-integrin-expressing and nonexpressing cells and this lysis is independent of the presence of sialic acid residues. In conclusion, LtxA not only is cytotoxic to β2-integrin-expressing cells but can potentially initiate cell lysis in all cells that present a sufficient density of sialic acid groups on their plasma membrane.
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50
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Brennan M, Cox D. The therapeutic potential of I-domain integrins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 819:157-78. [PMID: 25023174 DOI: 10.1007/978-94-017-9153-3_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Due to their role in processes central to cancer and autoimmune disease I-domain integrins are an attractive drug target. Both antibodies and small molecule antagonists have been discovered and tested in the clinic. Much of the effort has focused on αLβ2 antagonists. Maybe the most successful was the monoclonal antibody efalizumab, which was approved for the treatment of psoriasis but subsequently withdrawn from the market due to the occurrence of a serious adverse effect (progressive multifocal leukoencephalopathy). Other monoclonal antibodies were tested for the treatment of reperfusion injury, post-myocardial infarction, but failed to progress due to lack of efficacy. New potent small molecule inhibitors of αv integrins are promising reagents for treating fibrotic disease. Small molecule inhibitors targeting collagen-binding integrins have been discovered and future work will focus on identifying molecules selectively targeting each of the collagen receptors and identifying appropriate target diseases for future clinical studies.
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Affiliation(s)
- Marian Brennan
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland
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