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Cané L, Saffioti NA, Genetet S, Daza Millone MA, Ostuni MA, Schwarzbaum PJ, Mouro-Chanteloup I, Herlax V. Alpha hemolysin of E. coli induces hemolysis of human erythrocytes independently of toxin interaction with membrane proteins. Biochimie 2024; 216:3-13. [PMID: 37820991 DOI: 10.1016/j.biochi.2023.10.008] [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: 07/05/2023] [Revised: 09/13/2023] [Accepted: 10/08/2023] [Indexed: 10/13/2023]
Abstract
Alpha hemolysin (HlyA) is a hemolytic and cytotoxic protein secreted by uropathogenic strains of E. coli. The role of glycophorins (GPs) as putative receptors for HlyA binding to red blood cells (RBCs) has been debated. Experiments using anti-GPA/GPB antibodies and a GPA-specific epitope nanobody to block HlyA-GP binding on hRBCs, showed no effect on hemolytic activity. Similarly, the hemolysis induced by HlyA remained unaffected when hRBCs from a GPAnull/GPBnull variant were used. Surface Plasmon Resonance experiments revealed similar values of the dissociation constant between GPA and either HlyA, ProHlyA (inactive protoxin), HlyAΔ914-936 (mutant of HlyA lacking the binding domain to GPA) or human serum albumin, indicating that the binding between the proteins and GPA is not specific. Although far Western blot followed by mass spectroscopy analyses suggested that HlyA interacts with Band 3 and spectrins, hemolytic experiments on spectrin-depleted hRBCs and spherocytes, indicated these proteins do not mediate the hemolytic process. Our results unequivocally demonstrate that neither glycophorins, nor Band 3 and spectrins mediate the cytotoxic activity of HlyA on hRBCs, thereby challenging the HlyA-receptor hypothesis. This finding holds significant relevance for the design of anti-toxin therapeutic strategies, particularly in light of the growing antibiotic resistance exhibited by bacteria.
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Affiliation(s)
- Lucía Cané
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET. Facultad de Ciencias Médicas. Universidad Nacional de La Plata, Argentina
| | - Nicolás Andrés Saffioti
- Instituto de Química y Fisico-Química Biológicas (IQUIFIB) "Prof. Alejandro C. Paladini", Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina; Instituto de Nanosistemas, Universidad de General San Martín, Avenida 25 de Mayo 1021, San Martín, Buenos Aires, Argentina
| | - Sandrine Genetet
- Université Paris Cité and Université des Antilles, INSERM, BIGR, F-75015, Paris, France
| | - María Antonieta Daza Millone
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT- La Plata, CONICET. Universidad Nacional de La Plata, Sucursal 4 Casilla de Correo 16, 1900, La Plata, Argentina
| | - Mariano A Ostuni
- Université Paris Cité and Université des Antilles, INSERM, BIGR, F-75015, Paris, France
| | - Pablo J Schwarzbaum
- Instituto de Química y Fisico-Química 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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2
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Cané L, Guzmán F, Balatti G, Daza Millone MA, Pucci Molineris M, Maté S, Martini MF, Herlax V. Biophysical Analysis to Assess the Interaction of CRAC and CARC Motif Peptides of Alpha Hemolysin of Escherichia coli with Membranes. Biochemistry 2023. [PMID: 37224476 DOI: 10.1021/acs.biochem.3c00164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Alpha hemolysin of Escherichia coli (HlyA) is a pore-forming protein, which is a prototype of the "Repeat in Toxins" (RTX) family. It was demonstrated that HlyA-cholesterol interaction facilitates the insertion of the toxin into membranes. Putative cholesterol-binding sites, called cholesterol recognition/amino acid consensus (CRAC), and CARC (analogous to CRAC but with the opposite orientation) were identified in the HlyA sequence. In this context, two peptides were synthesized, one derived from a CARC site from the insertion domain of the toxin (residues 341-353) (PEP 1) and the other one from a CRAC site from the domain between the acylated lysines (residues 639-644) (PEP 2), to study their role in the interaction of HlyA with membranes. The interaction of peptides with membranes of different lipid compositions (pure POPC and POPC/Cho of 4:1 and 2:1 molar ratios) was analyzed by surface plasmon resonance and molecular dynamics simulations. Results demonstrate that both peptides interact preferentially with Cho-containing membranes, although PEP 2 presents a lower KD than PEP 1. Molecular dynamics simulation results indicate that the insertion and interaction of PEP 2 with Cho-containing membranes are more prominent than those caused by PEP 1. The hemolytic activity of HlyA in the presence of peptides indicates that PEP 2 was the only one that inhibits HlyA activity, interfering in the binding between the toxin and cholesterol.
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Affiliation(s)
- Lucía Cané
- CCT-La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), 60 y 120, La Plata 1900, Argentina
| | - Fanny Guzmán
- Núcleo de Biotecnología Curauma (NBC), Pontificia Universidad Católica de Valparaíso, Valparaíso 2373223, Chile
| | - Galo Balatti
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes. Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Roque Sáenz Peña 352, Bernal, Buenos Aires 1876, Argentina
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Metabolismo del Fármaco (IQUIMEFA). Junín 956, Buenos Aires 1113, Argentina
| | - María Antonieta Daza Millone
- CCT-La Plata, CONICET. Universidad Nacional de La Plata, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Sucursal 4 Casilla de Correo 16, La Plata 1900, Argentina
| | - Melisa Pucci Molineris
- CCT-La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), 60 y 120, La Plata 1900, Argentina
| | - Sabina Maté
- CCT-La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), 60 y 120, La Plata 1900, Argentina
| | - M Florencia Martini
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Metabolismo del Fármaco (IQUIMEFA). Junín 956, Buenos Aires 1113, Argentina
- Cátedra de Química Medicinal, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires 1113, Argentina
| | - Vanesa Herlax
- CCT-La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), 60 y 120, La Plata 1900, Argentina
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3
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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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4
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Lipid-A-dependent and cholesterol-dependent dynamics properties of liposomes from gram-negative bacteria in ESKAPE. Sci Rep 2022; 12:19474. [PMID: 36376343 PMCID: PMC9663605 DOI: 10.1038/s41598-022-22886-7] [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: 05/12/2022] [Accepted: 10/20/2022] [Indexed: 11/16/2022] Open
Abstract
AntiMicrobial Resistance (AMR) is a worldwide health emergency. ESKAPE pathogens include the most relevant AMR bacterial families. In particular, Gram-negative bacteria stand out due to their cell envelope complexity which exhibits strong resistance to antimicrobials. A key element for AMR is the chemical structure of lipid A, modulating the physico-chemical properties of the membrane and permeability to antibiotics. Liposomes are used as models of bacterial membrane infective vesicles. In this work, coarse-grained molecular dynamics simulations were used to model liposomes from ESKAPE Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa). We captured the role of lipid A, cardiolipin and cholesterol on liposome morphology and physico-chemical properties. Additionally, the reported antimicrobial peptides Cecropin B1, JB95, and PTCDA1-kf, were used to unveil their implications on membrane disruption. This study opens a promising starting point to understand molecular keys of bacterial membranes and to promote the discovery of new antimicrobials to overcome AMR.
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Histidine 19 Residue Is Essential for Cell Internalization of Antifungal Peptide SmAPα1-21 Derived from the α-Core of the Silybum marianum Defensin DefSm2-D in Fusarium graminearum. Antibiotics (Basel) 2022; 11:antibiotics11111501. [PMID: 36358156 PMCID: PMC9686561 DOI: 10.3390/antibiotics11111501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 10/25/2022] [Accepted: 10/25/2022] [Indexed: 11/30/2022] Open
Abstract
The synthetic peptide SmAPα1-21 (KLCEKPSKTWFGNCGNPRHCG) derived from DefSm2-D defensin α-core is active at micromolar concentrations against the phytopathogenic fungus Fusarium graminearum and has a multistep mechanism of action that includes alteration of the fungal cell wall and membrane permeabilization. Here, we continued the study of this peptide’s mode of action and explored the correlation between the biological activity and its primary structure. Transmission electron microscopy was used to study the ultrastructural effects of SmAPα1-21 in conidial cells. New peptides were designed by modifying the parent peptide SmAPα1-21 (SmAPH19R and SmAPH19A, where His19 was replaced by Arg or Ala, respectively) and synthesized by the Fmoc solid phase method. Antifungal activity was determined against F. graminearum. Membrane permeability and subcellular localization in conidia were studied by confocal laser scanning microscopy (CLSM). Reactive oxygen species (ROS) production was assessed by fluorescence spectroscopy and CLSM. SmAPα1-21 induced peroxisome biogenesis and oxidative stress through ROS production in F. graminearum and was internalized into the conidial cells’ cytoplasm. SmAPH19R and SmAPH19A were active against F. graminearum with minimal inhibitory concentrations (MICs) of 38 and 100 µM for SmAPH19R and SmAPH19A, respectively. The replacement of His19 by Ala produced a decrease in the net charge with a significant increase in the MIC, thus evidencing the importance of the positive charge in position 19 of the antifungal peptide. Like SmAPα1-21, SmAP2H19A and SmAP2H19R produced the permeabilization of the conidia membrane and induced oxidative stress through ROS production. However, SmAPH19R and SmAPH19A were localized in the conidia cell wall. The replacement of His19 by Ala turned all the processes slower. The extracellular localization of peptides SmAPH19R and SmAPH19A highlights the role of the His19 residue in the internalization.
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Four Cholesterol-Recognition Motifs in the Pore-Forming and Translocation Domains of Adenylate Cyclase Toxin Are Essential for Invasion of Eukaryotic Cells and Lysis of Erythrocytes. Int J Mol Sci 2022; 23:ijms23158703. [PMID: 35955837 PMCID: PMC9369406 DOI: 10.3390/ijms23158703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/21/2022] [Accepted: 08/02/2022] [Indexed: 12/05/2022] Open
Abstract
Adenylate Cyclase Toxin (ACT or CyaA) is one of the important virulence factors secreted by Bordetella pertussis, the bacterium causative of whooping cough. ACT debilitates host defenses by production of unregulated levels of cAMP into the cell cytosol upon delivery of its N-terminal domain with adenylate cyclase activity (AC domain) and by forming pores in the plasma membrane of macrophages. Binding of soluble toxin monomers to the plasma membrane of target cells and conversion into membrane-integrated proteins are the first and last step for these toxin activities; however, the molecular determinants in the protein or the target membrane that govern this conversion to an active toxin form are fully unknown. It was previously reported that cytotoxic and cytolytic activities of ACT depend on membrane cholesterol. Here we show that ACT specifically interacts with membrane cholesterol, and find in two membrane-interacting ACT domains, four cholesterol-binding motifs that are essential for AC domain translocation and lytic activities. We hypothesize that direct ACT interaction with membrane cholesterol through those four cholesterol-binding motifs drives insertion and stabilizes the transmembrane topology of several helical elements that ultimately build the ACT structure for AC delivery and pore-formation, thereby explaining the cholesterol-dependence of the ACT activities. The requirement for lipid-mediated stabilization of transmembrane helices appears to be a unifying mechanism to modulate toxicity in pore-forming toxins.
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New Antimicrobial Peptide with Two CRAC Motifs: Activity against Escherichia coli and Bacillus subtilis. Microorganisms 2022; 10:microorganisms10081538. [PMID: 36013956 PMCID: PMC9412426 DOI: 10.3390/microorganisms10081538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/21/2022] [Accepted: 07/27/2022] [Indexed: 02/04/2023] Open
Abstract
Due to the emergence of multiple antibiotic resistance in many pathogens, the studies on new antimicrobial peptides (AMPs) have become a priority scientific direction in fundamental and applied biology. Diverse mechanisms underlie the antibacterial action of AMPs. Among them are the effects that AMPs cause on bacterial cell membranes. In this work, we studied the antibacterial activity of a peptide named P4 with the following sequence RTKLWEMLVELGNMDKAVKLWRKLKR that was constructed from two alpha-helical fragments of the influenza virus protein M1 and containing two cholesterol-recognizing amino-acid consensus (CRAC) motifs. Previously we have shown that 50 μM of peptide P4 is toxic to cultured mouse macrophages. In the present work, we have found that peptide P4 inhibits the growth of E. coli and B. subtilis strains at concentrations that are significantly lower than the cytotoxic concentration that was found for macrophages. The half-maximal inhibitory concentration (IC50) for B. subtilis and E. coli cells were 0.07 ± 0.01 μM and 1.9 ± 0.4 μM, respectively. Scramble peptide without CRAC motifs did not inhibit the growth of E. coli cells and was not cytotoxic for macrophages but had an inhibitory effect on the growth of B. subtilis cells (IC50 0.4 ± 0.2 μM). A possible involvement of CRAC motifs and membrane sterols in the mechanism of the antimicrobial action of the P4 peptide is discussed. We assume that in the case of the Gram-negative bacterium E. coli, the mechanism of the toxic action of peptide P4 is related to the interaction of CRAC motifs with sterols that are present in the bacterial membrane, whereas in the case of the Gram-positive bacterium B. subtilis, which lacks sterols, the toxic action of peptide P4 is based on membrane permeabilization through the interaction of the peptide cationic domain and anionic lipids of the bacterial membrane. Whatever the mechanism can be, we report antimicrobial activity of the peptide P4 against the representatives of Gram-positive (B. subtilis) and Gram-negative (E. coli) bacteria.
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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; 10:518. [PMID: 35336094 PMCID: PMC8953716 DOI: 10.3390/microorganisms10030518] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [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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Affiliation(s)
| | | | | | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (K.F.); (W.U.R.); (A.O.)
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Interactive Dynamics of Cell Volume and Cell Death in Human Erythrocytes Exposed to α-Hemolysin from Escherichia coli. Int J Mol Sci 2022; 23:ijms23020872. [PMID: 35055067 PMCID: PMC8778525 DOI: 10.3390/ijms23020872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/09/2022] [Accepted: 01/11/2022] [Indexed: 12/16/2022] Open
Abstract
α-hemolysin (HlyA) of E. coli binds irreversibly to human erythrocytes and induces cell swelling, ultimately leading to hemolysis. We characterized the mechanism involved in water transport induced by HlyA and analyzed how swelling and hemolysis might be coupled. Osmotic water permeability (Pf) was assessed by stopped-flow light scattering. Preincubation with HlyA strongly reduced Pf in control- and aquaporin 1-null red blood cells, although the relative Pf decrease was similar in both cell types. The dynamics of cell volume and hemolysis on RBCs was assessed by electrical impedance, light dispersion and hemoglobin release. Results show that HlyA induced erythrocyte swelling, which is enhanced by purinergic signaling, and is coupled to osmotic hemolysis. We propose a mathematical model of HlyA activity where the kinetics of cell volume and hemolysis in human erythrocytes depend on the flux of osmolytes across the membrane, and on the maximum volume that these cells can tolerate. Our results provide new insights for understanding signaling and cytotoxicity mediated by HlyA in erythrocytes.
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González Bullón D, Uribe KB, Amuategi J, Martín C, Ostolaza H. Cholesterol stimulates the lytic activity of Adenylate Cyclase Toxin on lipid membranes by promoting toxin oligomerization and formation of pores with a greater effective size. FEBS J 2021; 288:6795-6814. [PMID: 34216517 PMCID: PMC9290974 DOI: 10.1111/febs.16107] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/27/2021] [Accepted: 07/02/2021] [Indexed: 11/28/2022]
Abstract
Several toxins acting on animal cells present different, but specific, interactions with cholesterol. Bordetella pertussis infects the human respiratory tract and causes whooping cough, a highly contagious and resurgent disease. Its virulence factor adenylate cyclase toxin (ACT) plays an important role in the course of infection. ACT is a pore‐forming cytolysin belonging to the Repeats in ToXin (RTX) family of leukotoxins/hemolysins and is capable of permeabilizing several cell types and lipid vesicles. Previously, we observed that in the presence of cholesterol ACT induces greater liposome permeabilization. Similarly, recent reports also implicate cholesterol in the cytotoxicity of an increasing number of pore‐forming RTX toxins. However, the mechanistic details by which this sterol promotes the lytic activity of ACT or of these other RTX toxins remain largely unexplored and poorly understood. Here, we have applied a combination of biophysical techniques to dissect the role of cholesterol in pore formation by ACT. Our results indicate that cholesterol enhances the lytic potency of ACT by promoting toxin oligomerization, a step which is indispensable for ACT to accomplish membrane permeabilization and cell lysis. Since our experimental design eliminates the possibility that this cholesterol effect derives from toxin accumulation due to lateral lipid phase segregation, we hypothesize that cholesterol facilitates lytic pore formation, by favoring a toxin conformation more prone to protein–protein interactions and oligomerization. Our data shed light on the complex relationship between lipid membranes and protein toxins acting on these membranes. Coupling cholesterol binding, increased oligomerization and increased lytic activity is likely pertinent for other RTX cytolysins.
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Affiliation(s)
- David González Bullón
- Department of Biochemistry and Molecular Biology, Biofisika Institute, (UPV/EHU, CSIC), University of Basque Country (UPV/EHU), Bilbao, Spain
| | - Kepa B Uribe
- Department of Biochemistry and Molecular Biology, Biofisika Institute, (UPV/EHU, CSIC), University of Basque Country (UPV/EHU), Bilbao, Spain
| | - Jone Amuategi
- Department of Biochemistry and Molecular Biology, Biofisika Institute, (UPV/EHU, CSIC), University of Basque Country (UPV/EHU), Bilbao, Spain
| | - César Martín
- Department of Biochemistry and Molecular Biology, Biofisika Institute, (UPV/EHU, CSIC), University of Basque Country (UPV/EHU), Bilbao, Spain
| | - Helena Ostolaza
- Department of Biochemistry and Molecular Biology, Biofisika Institute, (UPV/EHU, CSIC), University of Basque Country (UPV/EHU), Bilbao, Spain
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Reid LO, Thomas AH, Herlax V, Dántola ML. Role of Tryptophan Residues in the Toxicity and Photosensitized Inactivation of Escherichia coli α-Hemolysin. Biochemistry 2020; 59:4213-4224. [PMID: 33108867 DOI: 10.1021/acs.biochem.0c00660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
α-Hemolysin (HlyA) is an extracellular protein toxin secreted by uropathogenic strains of Escherichia coli that inserts into membranes of eukaryotic cells. The main goal of this work was to investigate the involvement of tryptophan (W) residues in the hemolytic activity of HlyA. We investigated the hemolytic activity of six single-point mutant proteins, in which one of the four Ws was replaced by cysteine (C) or leucine (L). We also analyzed the photoinactivation of HlyA with pterin (Ptr), an endogenous photosensitizer, as a method of unspecific oxidation of W and tyrosine (Y) residues. HlyA photoinactivation was analyzed by ultraviolet-visible spectrophotometry, hemolytic activity measurement, fluorescence spectroscopy, and electrophoretic analysis. The results indicate that Ws are important in the hemolytic process. Specifically, the chemical structure of the amino acid at position 578 is important for the acylation of HlyA at residue K563. Furthermore, the exposure of HlyA to ultraviolet radiation, with energy similar to that experienced under sun exposure, in the presence of Ptr induces the inactivation of the toxin, causing chemical changes in, at least, W and Y, the rate of damage to W residues being faster than that observed for Y residues. This work not only deepens our understanding of the structure-function relationship of the toxin but also introduces the possibility of using photoinactivation of HlyA for potential applications such as obtaining innocuous molecules for vaccine production and the elimination of the toxin from contaminated surfaces and drinking water.
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Affiliation(s)
- Lara O Reid
- Instituto de Investigaciones Fisicoquı́micas Teóricas y Aplicadas (INIFTA), Departamento de Quı́mica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT La Plata-CONICET, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina
| | - Andrés H Thomas
- Instituto de Investigaciones Fisicoquı́micas Teóricas y Aplicadas (INIFTA), Departamento de Quı́mica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT La Plata-CONICET, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina
| | - Vanesa Herlax
- Instituto de Investigaciones Bioquı́micas La Plata (INIBIOLP), CCT-La Plata, CONICET, UNLP, Facultad de Ciencias Médicas, 60 y 120 La Plata, 1900 La Plata, Argentina
| | - M Laura Dántola
- Instituto de Investigaciones Fisicoquı́micas Teóricas y Aplicadas (INIFTA), Departamento de Quı́mica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT La Plata-CONICET, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina
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12
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Fujiwara S, Shoji K, Watanabe C, Kawano R, Yanagisawa M. Microfluidic Formation of Honeycomb-Patterned Droplets Bounded by Interface Bilayers via Bimodal Molecular Adsorption. MICROMACHINES 2020; 11:mi11070701. [PMID: 32698458 PMCID: PMC7407938 DOI: 10.3390/mi11070701] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/14/2020] [Accepted: 07/16/2020] [Indexed: 01/02/2023]
Abstract
Assembled water-in-oil droplets bounded by lipid bilayers are used in synthetic biology as minimal models of cell tissue. Microfluidic devices successfully generate monodispersed droplets and assemble them via droplet interface bilayesr (DIB) formation. However, a honeycomb pattern of DIB-bounded droplets, similar to epithelial tissues, remains unrealized because the rapid DIB formation between the droplets hinders their ability to form the honeycomb pattern. In this paper, we demonstrate the microfluidic formation of a honeycomb pattern of DIB-bounded droplets using two surfactants with different adsorption rates on the droplet surface. A non-DIB forming surfactant (sorbitan monooleate, Span 80) was mixed with a lipid (1,2-dioleoyl-sn-glycero-3-phosphocholine, PC), whose adsorption rate on the droplet surface and saturated interfacial tension were lower than those of Span 80. By changing the surfactant composition, we established the conditions under which the droplets initially form a honeycomb pattern and subsequently adhere to each other via DIB formation to minimize the interfacial energy. In addition, the reconstituted membrane protein nanopores at the DIBs were able to transport molecules. This new method, using the difference in the adsorption rates of two surfactants, allows the formation of a honeycomb pattern of DIB-bounded droplets in a single step, and thus facilitates research using DIB-bounded droplet assemblies.
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Affiliation(s)
- Shougo Fujiwara
- Komaba Institute for Science, The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo 153-8902, Japan; (S.F.); (C.W.)
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Kan Shoji
- Department of Biotechnology and Life Science., Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan; (K.S.); (R.K.)
- Department of Mechanical Engineering, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka, Niigata 940-2188, Japan
| | - Chiho Watanabe
- Komaba Institute for Science, The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo 153-8902, Japan; (S.F.); (C.W.)
| | - Ryuji Kawano
- Department of Biotechnology and Life Science., Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan; (K.S.); (R.K.)
| | - Miho Yanagisawa
- Komaba Institute for Science, The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo 153-8902, Japan; (S.F.); (C.W.)
- Department of Basic Science, The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo 153-8902, Japan
- Correspondence: ; Tel.: +81-3-5465-7302
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13
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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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14
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Nygren P, Balashova N, Brown AC, Kieba I, Dhingra A, Boesze-Battaglia K, Lally ET. Aggregatibacter actinomycetemcomitans leukotoxin causes activation of lymphocyte function-associated antigen 1. Cell Microbiol 2018; 21:e12967. [PMID: 30329215 DOI: 10.1111/cmi.12967] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 09/20/2018] [Accepted: 10/05/2018] [Indexed: 11/29/2022]
Abstract
Repeats-in-toxin leukotoxin (LtxA) produced by the oral bacterium Aggregatibacter actinomycetemcomitans kills human leukocytes in a lymphocyte function-associated antigen 1 (LFA-1, integrin αL /β2 )-dependent manner, although the mechanism for this interaction has not been identified. The LtxA internalisation by LFA-1-expressing cells was explored with florescence resonance energy transfer (FRET) microscopy using a cell line that expresses LFA-1 with a cyan fluorescent protein-tagged cytosolic αL domain and a yellow fluorescent protein-tagged β2 domain. Phorbol 12-myristate 13-acetate activation of LFA-1 caused transient cytosolic domain separation. However, addition of LtxA resulted in an increase in FRET, indicating that LtxA brings the cytosolic domains closer together, compared with the inactive state. Unlike activation, this effect was not transient, lasting more than 30 min. Equilibrium constants of LtxA binding to the cytoplasmic domains of both αL and β2 were determined using surface plasmon resonance. LtxA has a strong affinity for the cytosolic domains of both the αL and β2 subunits (Kd = 15 and 4.2 nM, respectively) and a significantly lower affinity for the cytoplasmic domains of other integrin αM , αX , and β3 subunits (Kd = 400, 180, and 230 nM, respectively), used as controls. Peptide fragments of αL and β2 show that LtxA binds membrane-proximal domain of αL and intermediate domain of β2 .
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Affiliation(s)
- Patrik Nygren
- Departments of Biochemistry, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nataliya Balashova
- Departments of Pathology, School of Dental Medicine, and the Division of Hematology/Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Angela C Brown
- Departments of Pathology, School of Dental Medicine, and the Division of Hematology/Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Irene Kieba
- Departments of Pathology, School of Dental Medicine, and the Division of Hematology/Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Anuradha Dhingra
- Departments of Biochemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Edward T Lally
- Departments of Pathology, School of Dental Medicine, and the Division of Hematology/Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
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15
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Osickova A, Balashova N, Masin J, Sulc M, Roderova J, Wald T, Brown AC, Koufos E, Chang EH, Giannakakis A, Lally ET, Osicka R. Cytotoxic activity of Kingella kingae RtxA toxin depends on post-translational acylation of lysine residues and cholesterol binding. Emerg Microbes Infect 2018; 7:178. [PMID: 30405113 PMCID: PMC6221878 DOI: 10.1038/s41426-018-0179-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/04/2018] [Accepted: 10/08/2018] [Indexed: 11/28/2022]
Abstract
Kingella kingae is a member of the commensal oropharyngeal flora of young children. Improvements in detection methods have led to the recognition of K. kingae as an emerging pathogen that frequently causes osteoarticular infections in children and a severe form of infective endocarditis in children and adults. Kingella kingae secretes a membrane-damaging RTX (Repeat in ToXin) toxin, RtxA, which is implicated in the development of clinical infections. However, the mechanism by which RtxA recognizes and kills host cells is largely unexplored. To facilitate structure-function studies of RtxA, we have developed a procedure for the overproduction and purification of milligram amounts of biologically active recombinant RtxA. Mass spectrometry analysis revealed the activation of RtxA by post-translational fatty acyl modification on the lysine residues 558 and/or 689 by the fatty-acyltransferase RtxC. Acylated RtxA was toxic to various human cells in a calcium-dependent manner and possessed pore-forming activity in planar lipid bilayers. Using various biochemical and biophysical approaches, we demonstrated that cholesterol facilitates the interaction of RtxA with artificial and cell membranes. The results of analyses using RtxA mutant variants suggested that the interaction between the toxin and cholesterol occurs via two cholesterol recognition/interaction amino acid consensus motifs located in the C-terminal portion of the pore-forming domain of the toxin. Based on our observations, we conclude that the cytotoxic activity of RtxA depends on post-translational acylation of the K558 and/or K689 residues and on the toxin binding to cholesterol in the membrane.
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Affiliation(s)
- Adriana Osickova
- Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic.,Faculty of Science, Charles University, Prague, Czech Republic
| | - Nataliya Balashova
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jiri Masin
- Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic
| | - Miroslav Sulc
- Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic.,Faculty of Science, Charles University, Prague, Czech Republic
| | - Jana Roderova
- Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic
| | - Tomas Wald
- Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic.,Department of Orofacial Sciences and Program in Craniofacial Biology, University of California, San Francisco, CA, USA
| | - Angela C Brown
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, USA
| | - Evan Koufos
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, USA
| | - En Hyung Chang
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, USA
| | - Alexander Giannakakis
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.,The Department of Cell and Molecular Biology at Karolinska Institutet, Stockholm, Sweden
| | - Edward T Lally
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Radim Osicka
- Institute of Microbiology of the CAS, v.v.i., Prague, Czech Republic.
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16
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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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17
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Vázquez RF, Daza Millone MA, Pavinatto FJ, Herlax VS, Bakás LS, Oliveira ON, Vela ME, Maté SM. Interaction of acylated and unacylated forms of E. coli alpha-hemolysin with lipid monolayers: a PM-IRRAS study. Colloids Surf B Biointerfaces 2017; 158:76-83. [PMID: 28683345 DOI: 10.1016/j.colsurfb.2017.06.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/12/2017] [Accepted: 06/19/2017] [Indexed: 11/18/2022]
Abstract
Uropathogenic strains of Escherichia coli produce virulence factors, such as the protein toxin alpha-hemolysin (HlyA), that enable the bacteria to colonize the host and establish an infection. HlyA is synthetized as a protoxin (ProHlyA) that is transformed into the active form in the bacterial cytosol by the covalent linkage of two fatty-acyl moieties to the polypeptide chain before the secretion of HlyA into the extracellular medium. The aim of this work was to investigate the effect of the fatty acylation of HlyA on protein conformation and protein-membrane interactions. Polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS) experiments were performed at the air-water interface, and lipid monolayers mimicking the outer leaflet of red-blood-cell membranes were used as model systems for the study of protein-membrane interaction. According to surface-pressure measurements, incorporation of the acylated protein into the lipid films was faster than that of the nonacylated form. PM-IRRAS measurements revealed that the adsorption of the proteins to the lipid monolayers induced disorder in the lipid acyl chains and also changed the elastic properties of the films independently of protein acylation. No significant difference was observed between HlyA and ProHlyA in the interaction with the model lipid monolayers; but when these proteins became adsorbed on a bare air-water interface, they adopted different secondary structures. The assumption of the correct protein conformation at a hydrophobic-hydrophilic interface could constitute a critical condition for biologic activity.
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Affiliation(s)
- Romina F Vázquez
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET. Facultad de Ciencias Médicas. Universidad Nacional de La Plata, 60 y 120, 1900, La Plata, Argentina
| | - María A Daza Millone
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT- La Plata, CONICET. Universidad Nacional de La Plata, Sucursal 4 Casilla de Correo 16, 1900, La Plata, Argentina
| | - Felippe J Pavinatto
- Instituto de Física de São Carlos (IFSC), Universidade de São Paulo, SP, Brazil
| | - Vanesa S Herlax
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET. Facultad de Ciencias Médicas. Universidad Nacional de La Plata, 60 y 120, 1900, La Plata, Argentina
| | - Laura S Bakás
- Centro de Investigación de Proteínas Vegetales (CIPROVE), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas. Universidad Nacional de La Plata. 47 y 115, 1900, La Plata, Argentina
| | - Osvaldo N Oliveira
- Instituto de Física de São Carlos (IFSC), Universidade de São Paulo, SP, Brazil
| | - María E Vela
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT- La Plata, CONICET. Universidad Nacional de La Plata, Sucursal 4 Casilla de Correo 16, 1900, La Plata, Argentina
| | - Sabina M Maté
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET. Facultad de Ciencias Médicas. Universidad Nacional de La Plata, 60 y 120, 1900, La Plata, Argentina.
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18
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Koufos E, Chang EH, Rasti ES, Krueger E, Brown AC. Use of a Cholesterol Recognition Amino Acid Consensus Peptide To Inhibit Binding of a Bacterial Toxin to Cholesterol. Biochemistry 2016; 55:4787-97. [PMID: 27504950 DOI: 10.1021/acs.biochem.6b00430] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Recognition of and binding to cholesterol on the host cell membrane is an initial step in the mechanism of numerous pathogens, including viruses, bacteria, and bacterial toxins; however, a viable method of inhibiting this interaction has not yet been uncovered. Here, we describe the mechanism by which a cholesterol recognition amino acid consensus peptide interacts with cholesterol and inhibits the activity of a cholesterol-binding bacterial leukotoxin (LtxA). Using a series of biophysical techniques, we have shown that the peptide recognizes the hydroxyl group of cholesterol with nanomolar affinity and does not disrupt membrane packing, suggesting that it sits primarily near the membrane surface. As a result, LtxA is unable to bind to cholesterol or subsequently become internalized in host cells. Additionally, because cholesterol is not being removed from the cell membrane, the peptide-treated target cells remain viable over extended periods of time. We have demonstrated the use of this peptide in the inhibition of toxin activity for an antivirulence approach to the treatment of bacterial disease, and we anticipate that this approach might have broad utility in the inhibition of viral and bacterial pathogenesis.
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Affiliation(s)
- Evan Koufos
- Department of Chemical and Biomolecular Engineering, Lehigh University , Bethlehem, Pennsylvania 18015, United States
| | - En Hyung Chang
- Department of Chemical and Biomolecular Engineering, Lehigh University , Bethlehem, Pennsylvania 18015, United States
| | - Elnaz S Rasti
- Department of Chemical and Biomolecular Engineering, Lehigh University , Bethlehem, Pennsylvania 18015, United States
| | - Eric Krueger
- Department of Chemical and Biomolecular Engineering, Lehigh University , Bethlehem, Pennsylvania 18015, United States
| | - Angela C Brown
- Department of Chemical and Biomolecular Engineering, Lehigh University , Bethlehem, Pennsylvania 18015, United States
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19
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Vázquez RF, Maté SM, Bakás LS, Muñoz-Garay C, Herlax VS. Relationship between intracellular calcium and morphologic changes in rabbit erythrocytes: Effects of the acylated and unacylated forms of E. coli alpha-hemolysin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1944-53. [PMID: 27206406 DOI: 10.1016/j.bbamem.2016.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/15/2016] [Accepted: 05/16/2016] [Indexed: 12/28/2022]
Affiliation(s)
- Romina F Vázquez
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, 1900 La Plata, Argentina
| | - Sabina M Maté
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, 1900 La Plata, Argentina
| | - Laura S Bakás
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900 La Plata, Argentina
| | - Carlos Muñoz-Garay
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (UNAM), Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, Mexico
| | - Vanesa S Herlax
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, 1900 La Plata, Argentina.
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20
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Bettelheim KA, Goldwater PN. Escherichia coli and Sudden Infant Death Syndrome. Front Immunol 2015; 6:343. [PMID: 26191064 PMCID: PMC4490240 DOI: 10.3389/fimmu.2015.00343] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 06/19/2015] [Indexed: 01/02/2023] Open
Abstract
This review examines the association of strains of Escherichia coli with sudden infant death syndrome (SIDS) and the possible role these bacteria play in this enigmatic condition. The review addresses evidence for E. coli in SIDS infants, potential sources of E. coli in the environment, colonization by commensal and pathogenic strains, the variety of currently accepted pathotypes, and how these pathotypes could compromise intestinal integrity and induce inflammation. Both intestinal and extraintestinal pathotypes are compared in relation to the apparent liability in which virulence traits can be gained or lost by strains of E. coli. The way in which E. coli infections fit with current views on infant sleeping position and other SIDS risk factors is highlighted.
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Affiliation(s)
- Karl A Bettelheim
- Discipline of Paediatrics, School of Paediatrics and Reproductive Health, University of Adelaide , North Adelaide, SA , Australia
| | - Paul N Goldwater
- Discipline of Paediatrics, School of Paediatrics and Reproductive Health, University of Adelaide , North Adelaide, SA , Australia
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