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Silva MP, Rodrigues CG, Machado DC, Nogueira RA. Long-term memory in Staphylococcus aureus α-hemolysin ion channel kinetics. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:661-671. [PMID: 37542583 DOI: 10.1007/s00249-023-01675-8] [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: 06/20/2022] [Revised: 07/03/2023] [Accepted: 07/20/2023] [Indexed: 08/07/2023]
Abstract
The kinetics of an ion channel are classically understood as a random process. However, studies have shown that in complex ion channels, formed by multiple subunits, this process can be deterministic, presenting long-term memory. Staphylococcus aureus α-hemolysin (α-HL) is a toxin that acts as the major factor in Staphylococcus aureus virulence. α-HL is a water-soluble protein capable of forming ion channels into lipid bilayers, by insertion of an amphipathic β-barrel. Here, the α-HL was used as an experimental model to study memory in ion channel kinetics. We applied the approximate entropy (ApEn) approach to analyze randomness and the Detrended Fluctuation Analysis (DFA) to investigate the existence of long memory in α-HL channel kinetics. Single-channel currents were measured through experiments with α-HL channels incorporated in planar lipid bilayers. All experiments were carried out under the following conditions: 1 M NaCl solution, pH 4.5; transmembrane potential of + 40 mV and temperature 25 ± 1 °C. Single-channel currents were recorded in real-time in the memory of a microcomputer coupled to an A/D converter and a patch-clamp amplifier. The conductance value of the α-HL channels was 0.82 ± 0.0025 nS (n = 128). The DFA analysis showed that the kinetics of α-HL channels presents long-term memory ([Formula: see text] = 0.63 ± 0.04). The ApEn outcomes showed low complexity to dwell times when open (ApEno = 0.5514 ± 0.28) and closed (ApEnc = 0.1145 ± 0.08), corroborating the results of the DFA method.
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Affiliation(s)
- M P Silva
- Department of Animal Morphology and Physiology, Federal Rural University of Pernambuco, Recife, Pernambuco, Brazil
| | - C G Rodrigues
- Department of Biophysics and Radiobiology, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | - D C Machado
- Department of Biophysics and Radiobiology, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | - R A Nogueira
- Department of Animal Morphology and Physiology, Federal Rural University of Pernambuco, Recife, Pernambuco, Brazil.
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2
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Ziesemer S, Kuhn SO, Hahnenkamp A, Gerber M, Lutjanov E, Gruendling M, Hildebrandt JP. Staphylococcus aureus Alpha-Toxin in Deep Tracheal Aspirates—Preliminary Evidence for Its Presence in the Lungs of Sepsis Patients. Toxins (Basel) 2022; 14:toxins14070450. [PMID: 35878188 PMCID: PMC9320683 DOI: 10.3390/toxins14070450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/20/2022] [Accepted: 06/29/2022] [Indexed: 02/05/2023] Open
Abstract
The pore forming alpha-toxin (hemolysin A, Hla) of Staphylococcus aureus (S. aureus) is a major virulence factor with relevance for the pathogenicity of this bacterium, which is involved in many cases of pneumonia and sepsis in humans. Until now, the presence of Hla in the body fluids of potentially infected humans could only be shown indirectly, e.g., by the presence of antibodies against Hla in serum samples or by hemolysis testing on blood agar plates of bacterial culture supernatants of the clinical isolates. In addition, nothing was known about the concentrations of Hla actually reached in the body fluids of the infected hosts. Western blot analyses on 36 samples of deep tracheal aspirates (DTA) isolated from 22 hospitalized sepsis patients using primary antibodies against different epitopes of the Hla molecule resulted in the identification of six samples from five patients containing monomeric Hla (approx. 33 kDa). Two of these samples showed also signals at the molecular mass of heptameric Hla (232 kDa). Semiquantitative analyses of the samples revealed that the concentrations of monomeric Hla ranged from 16 to 3200 ng/mL. This is, to our knowledge, the first study directly showing the presence of S. aureus Hla in samples of airway surface liquid in human patients.
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Affiliation(s)
- Sabine Ziesemer
- Animal Physiology and Biochemistry, University of Greifswald, Felix Hausdorff-Strasse 1, D-17489 Greifswald, Germany; (S.Z.); (E.L.)
| | - Sven-Olaf Kuhn
- Department of Anesthesiology, University Hospital Greifswald, Ferdinand Sauerbruch-Strasse, D-17475 Greifswald, Germany; (S.-O.K.); (A.H.); (M.G.); (M.G.)
| | - Anke Hahnenkamp
- Department of Anesthesiology, University Hospital Greifswald, Ferdinand Sauerbruch-Strasse, D-17475 Greifswald, Germany; (S.-O.K.); (A.H.); (M.G.); (M.G.)
| | - Manuela Gerber
- Department of Anesthesiology, University Hospital Greifswald, Ferdinand Sauerbruch-Strasse, D-17475 Greifswald, Germany; (S.-O.K.); (A.H.); (M.G.); (M.G.)
| | - Elvira Lutjanov
- Animal Physiology and Biochemistry, University of Greifswald, Felix Hausdorff-Strasse 1, D-17489 Greifswald, Germany; (S.Z.); (E.L.)
| | - Matthias Gruendling
- Department of Anesthesiology, University Hospital Greifswald, Ferdinand Sauerbruch-Strasse, D-17475 Greifswald, Germany; (S.-O.K.); (A.H.); (M.G.); (M.G.)
| | - Jan-Peter Hildebrandt
- Animal Physiology and Biochemistry, University of Greifswald, Felix Hausdorff-Strasse 1, D-17489 Greifswald, Germany; (S.Z.); (E.L.)
- Correspondence: ; Tel.: +49-(0)3834-4204295
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3
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Kember M, Grandy S, Raudonis R, Cheng Z. Non-Canonical Host Intracellular Niche Links to New Antimicrobial Resistance Mechanism. Pathogens 2022; 11:pathogens11020220. [PMID: 35215166 PMCID: PMC8876822 DOI: 10.3390/pathogens11020220] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 02/03/2022] [Accepted: 02/05/2022] [Indexed: 12/04/2022] Open
Abstract
Globally, infectious diseases are one of the leading causes of death among people of all ages. The development of antimicrobials to treat infectious diseases has been one of the most significant advances in medical history. Alarmingly, antimicrobial resistance is a widespread phenomenon that will, without intervention, make currently treatable infections once again deadly. In an era of widespread antimicrobial resistance, there is a constant and pressing need to develop new antibacterial drugs. Unraveling the underlying resistance mechanisms is critical to fight this crisis. In this review, we summarize some emerging evidence of the non-canonical intracellular life cycle of two priority antimicrobial-resistant bacterial pathogens: Pseudomonas aeruginosa and Staphylococcus aureus. The bacterial factors that modulate this unique intracellular niche and its implications in contributing to resistance are discussed. We then briefly discuss some recent research that focused on the promises of boosting host immunity as a combination therapy with antimicrobials to eradicate these two particular pathogens. Finally, we summarize the importance of various strategies, including surveillance and vaccines, in mitigating the impacts of antimicrobial resistance in general.
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4
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Chen L, Liu Q, Liu Z, Li H, Liu X, Yu H. EGF Protects Epithelial Cells from Barrier Damage in Chronic Rhinosinusitis with Nasal Polyps. J Inflamm Res 2022; 15:439-450. [PMID: 35082512 PMCID: PMC8784255 DOI: 10.2147/jir.s345664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/24/2021] [Indexed: 12/12/2022] Open
Affiliation(s)
- Le Chen
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Research Units of New Technologies of Endoscopic Surgery in Skull Base Tumour, Chinese Academy of Medical Sciences, 2018RU003, Shanghai, People's Republlc of China
| | - Quan Liu
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Research Units of New Technologies of Endoscopic Surgery in Skull Base Tumour, Chinese Academy of Medical Sciences, 2018RU003, Shanghai, People's Republlc of China
| | - Zhuofu Liu
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Research Units of New Technologies of Endoscopic Surgery in Skull Base Tumour, Chinese Academy of Medical Sciences, 2018RU003, Shanghai, People's Republlc of China
| | - Han Li
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Research Units of New Technologies of Endoscopic Surgery in Skull Base Tumour, Chinese Academy of Medical Sciences, 2018RU003, Shanghai, People's Republlc of China
| | - Xiang Liu
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Research Units of New Technologies of Endoscopic Surgery in Skull Base Tumour, Chinese Academy of Medical Sciences, 2018RU003, Shanghai, People's Republlc of China
| | - Hongmeng Yu
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, People’s Republic of China
- Research Units of New Technologies of Endoscopic Surgery in Skull Base Tumour, Chinese Academy of Medical Sciences, 2018RU003, Shanghai, People's Republlc of China
- Correspondence: Hongmeng Yu; Xiang Liu Email ;
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5
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Liu C, Hao K, Liu Z, Liu Z, Guo N. Epigallocatechin gallate (EGCG) attenuates staphylococcal alpha-hemolysin (Hla)-induced NLRP3 inflammasome activation via ROS-MAPK pathways and EGCG-Hla interactions. Int Immunopharmacol 2021; 100:108170. [PMID: 34562843 DOI: 10.1016/j.intimp.2021.108170] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 09/08/2021] [Accepted: 09/15/2021] [Indexed: 12/21/2022]
Abstract
Alpha-hemolysin (Hla), the virulence factor secreted by Staphylococcus aureus (S. aureus), plays a critical role in infection and inflammation, which is a severe health burden worldwide. Therefore, it is necessary to develop a drug against Hla. Epigallocatechin gallate (EGCG), a polyphenol extracted from green tea, has excellent anti-inflammatory activity. In this study, we investigated the inhibitory effect of EGCG on Hla-induced NLRP3 inflammasome activation in vitro and in vivo and elucidated the potential molecular mechanism. We found that EGCG attenuated the hemolysis of Hla by inhibiting its secretion. Besides, EGCG significantly decreased overproduction of ROS and activation of MAPK signaling pathway induced by Hla, thereby markedly attenuating the expression of NLRP3 inflammasome-related proteins in THP-1 cells. Notably, EGCG could spontaneously bind to Hla with affinity constant of 1.71 × 10-4 M, thus blocking the formation of the Hla heptamer. Moreover, Hla-induced expression of NLRP3, ASC and caspase-1 protein and generation of IL-1β and IL-18 in the damaged liver tissue of mice were also significantly suppressed by EGCG in a dose-dependent manner. Collectively, EGCG could be a promising candidate for alleviating Hla-induced the activation of NLRP3 inflammasome, depending on ROS mediated MAPK signaling pathway, and inhibition of Hla secretion and heptamer formation. These findings will enlighten the applications of EGCG to reduce the S. aureus infection by targeting Hla in food and related pharmaceutical fields.
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Affiliation(s)
- Chunmei Liu
- College of Food Science and Engineering, Jilin University, Changchun 130062, China
| | - Kun Hao
- College of Food Science and Engineering, Jilin University, Changchun 130062, China
| | - Zuojia Liu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Zonghui Liu
- College of Food Science and Engineering, Jilin University, Changchun 130062, China
| | - Na Guo
- College of Food Science and Engineering, Jilin University, Changchun 130062, China.
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6
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Krones D, Rühling M, Becker KA, Kunz TC, Sehl C, Paprotka K, Gulbins E, Fraunholz M. Staphylococcus aureus α-Toxin Induces Acid Sphingomyelinase Release From a Human Endothelial Cell Line. Front Microbiol 2021; 12:694489. [PMID: 34394034 PMCID: PMC8358437 DOI: 10.3389/fmicb.2021.694489] [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: 04/13/2021] [Accepted: 07/05/2021] [Indexed: 11/14/2022] Open
Abstract
Staphylococcus aureus (S. aureus) is well known to express a plethora of toxins of which the pore-forming hemolysin A (α-toxin) is the best-studied cytolysin. Pore-forming toxins (PFT) permeabilize host membranes during infection thereby causing concentration-dependent effects in host cell membranes ranging from disordered ion fluxes to cytolysis. Host cells possess defense mechanisms against PFT attack, resulting in endocytosis of the breached membrane area and delivery of repair vesicles to the insulted plasma membrane as well as a concurrent release of membrane repair enzymes. Since PFTs from several pathogens have been shown to recruit membrane repair components, we here investigated whether staphylococcal α-toxin is able to induce these mechanisms in endothelial cells. We show that S. aureus α-toxin induced increase in cytosolic Ca2+ in endothelial cells, which was accompanied by p38 MAPK phosphorylation. Toxin challenge led to increased endocytosis of an extracellular fluid phase marker as well as increased externalization of LAMP1-positive membranes suggesting that peripheral lysosomes are recruited to the insulted plasma membrane. We further observed that thereby the lysosomal protein acid sphingomyelinase (ASM) was released into the cell culture medium. Thus, our results show that staphylococcal α-toxin triggers mechanisms in endothelial cells, which have been implicated in membrane repair after damage of other cell types by different toxins.
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Affiliation(s)
- David Krones
- Chair of Microbiology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Marcel Rühling
- Chair of Microbiology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Katrin Anne Becker
- Institute of Molecular Biology, University of Duisburg-Essen, University Hospital, Essen, Germany
| | - Tobias C Kunz
- Chair of Microbiology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Carolin Sehl
- Institute of Molecular Biology, University of Duisburg-Essen, University Hospital, Essen, Germany
| | - Kerstin Paprotka
- Chair of Microbiology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Erich Gulbins
- Institute of Molecular Biology, University of Duisburg-Essen, University Hospital, Essen, Germany.,Department of Surgery, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Martin Fraunholz
- Chair of Microbiology, Biocenter, University of Würzburg, Würzburg, Germany
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7
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Major Determinants of Airway Epithelial Cell Sensitivity to S. aureus Alpha-Toxin: Disposal of Toxin Heptamers by Extracellular Vesicle Formation and Lysosomal Degradation. Toxins (Basel) 2021; 13:toxins13030173. [PMID: 33668237 PMCID: PMC7996177 DOI: 10.3390/toxins13030173] [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: 01/29/2021] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 11/25/2022] Open
Abstract
Alpha-toxin is a major virulence factor of Staphylococcus aureus. Monomer binding to host cell membranes results in the formation of heptameric transmembrane pores. Among human model airway epithelial cell lines, A549 cells were most sensitive toward the toxin followed by 16HBE14o- and S9 cells. In this study we investigated the processes of internalization of pore-containing plasma membrane areas as well as potential pathways for heptamer degradation (lysosomal, proteasomal) or disposal (formation of exosomes/micro-vesicles). The abundance of toxin heptamers upon applying an alpha-toxin pulse to the cells declined both in extracts of whole cells and of cellular membranes of S9 cells, but not in those of 16HBE14o- or A549 cells. Comparisons of heptamer degradation rates under inhibition of lysosomal or proteasomal degradation revealed that an important route of heptamer degradation, at least in S9 cells, seems to be the lysosomal pathway, while proteasomal degradation appears to be irrelevant. Exosomes prepared from culture supernatants of toxin-exposed S9 cells contained alpha-toxin as well as low amounts of exosome and micro-vesicle markers. These results indicate that lysosomal degradation of internalized toxin heptamers may be the most important determinant of toxin-resistance of some types of airway epithelial cells.
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8
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Bonifacius A, Goldmann O, Floess S, Holtfreter S, Robert PA, Nordengrün M, Kruse F, Lochner M, Falk CS, Schmitz I, Bröker BM, Medina E, Huehn J. Staphylococcus aureus Alpha-Toxin Limits Type 1 While Fostering Type 3 Immune Responses. Front Immunol 2020; 11:1579. [PMID: 32849537 PMCID: PMC7427519 DOI: 10.3389/fimmu.2020.01579] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 06/15/2020] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus can cause life-threatening diseases, and hospital- as well as community-associated antibiotic-resistant strains are an emerging global public health problem. Therefore, prophylactic vaccines or immune-based therapies are considered as alternative treatment opportunities. To develop such novel treatment approaches, a better understanding of the bacterial virulence and immune evasion mechanisms and their potential effects on immune-based therapies is essential. One important staphylococcal virulence factor is alpha-toxin, which is able to disrupt the epithelial barrier in order to establish infection. In addition, alpha-toxin has been reported to modulate other cell types including immune cells. Since CD4+ T cell-mediated immunity is required for protection against S. aureus infection, we were interested in the ability of alpha-toxin to directly modulate CD4+ T cells. To address this, murine naïve CD4+ T cells were differentiated in vitro into effector T cell subsets in the presence of alpha-toxin. Interestingly, alpha-toxin induced death of Th1-polarized cells, while cells polarized under Th17 conditions showed a high resistance toward increasing concentrations of this toxin. These effects could neither be explained by differential expression of the cellular alpha-toxin receptor ADAM10 nor by differential activation of caspases, but might result from an increased susceptibility of Th1 cells toward Ca2+-mediated activation-induced cell death. In accordance with the in vitro findings, an alpha-toxin-dependent decrease of Th1 and concomitant increase of Th17 cells was observed in vivo during S. aureus bacteremia. Interestingly, corresponding subsets of innate lymphoid cells and γδ T cells were similarly affected, suggesting a more general effect of alpha-toxin on the modulation of type 1 and type 3 immune responses. In conclusion, we have identified a novel alpha-toxin-dependent immunomodulatory strategy of S. aureus, which can directly act on CD4+ T cells and might be exploited for the development of novel immune-based therapeutic approaches to treat infections with antibiotic-resistant S. aureus strains.
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Affiliation(s)
- Agnes Bonifacius
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Oliver Goldmann
- Department Infection Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Stefan Floess
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Silva Holtfreter
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Philippe A Robert
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Department Systems Immunology and Braunschweig Integrated Centre of Systems Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Maria Nordengrün
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Friederike Kruse
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Matthias Lochner
- Institute of Infection Immunology, TWINCORE, Centre for Experimental and Clinical Infection Research; A Joint Venture Between the Medical School Hannover and the Helmholtz Centre for Infection Research, Hanover, Germany.,Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hanover, Germany
| | - Christine S Falk
- Institute of Transplant Immunology, Hannover Medical School, Hanover, Germany.,DZIF, German Center for Infectious Diseases, TTU-IICH Hannover-Braunschweig Site, Hanover, Germany
| | - Ingo Schmitz
- Department Systems-Oriented Immunology and Inflammation Research, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Institute for Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Department of Molecular Immunology, Ruhr-University Bochum, Bochum, Germany
| | - Barbara M Bröker
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Eva Medina
- Department Infection Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Jochen Huehn
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
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9
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Möller N, Ziesemer S, Hildebrandt P, Assenheimer N, Völker U, Hildebrandt JP. S. aureus alpha-toxin monomer binding and heptamer formation in host cell membranes - Do they determine sensitivity of airway epithelial cells toward the toxin? PLoS One 2020; 15:e0233854. [PMID: 32470006 PMCID: PMC7259691 DOI: 10.1371/journal.pone.0233854] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/13/2020] [Indexed: 11/18/2022] Open
Abstract
Alpha-toxin (Hla) is a major virulence factor of Staphylococcus aureus (S. aureus) and plays an important role in S. aureus-induced pneumonia. It binds as a monomer to the cell surface of eukaryotic host cells and forms heptameric transmembrane pores. Sensitivities toward the toxin of various types of potential host cells have been shown to vary substantially, and the reasons for these differences are unclear. We used three human model airway epithelial cell lines (16HBE14o-, S9, A549) to correlate cell sensitivity (measured as rate of paracellular gap formation in the cell layers) with Hla monomer binding, presence of the potential Hla receptors ADAM10 or α5β1 integrin, presence of the toxin-stabilizing factor caveolin-1 as well as plasma membrane lipid composition (phosphatidylserine/choline, sphingomyelin). The abundance of ADAM10 correlated best with gap formation or cell sensitivities, respectively, when the three cell types were compared. Caveolin-1 or α5β1 integrin did not correlate with toxin sensitivity. The relative abundance of sphingomyelin in plasma membranes may also be used as a proxi for cellular sensitivity against alpha-toxin as sphingomyelin abundances correlated well with the intensities of alpha-toxin mediated gap formation in the cell layers.
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Affiliation(s)
- Nils Möller
- Animal Physiology and Biochemistry, University of Greifswald, Greifswald, Germany
| | - Sabine Ziesemer
- Animal Physiology and Biochemistry, University of Greifswald, Greifswald, Germany
| | - Petra Hildebrandt
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Nadine Assenheimer
- Animal Physiology and Biochemistry, University of Greifswald, Greifswald, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Jan-Peter Hildebrandt
- Animal Physiology and Biochemistry, University of Greifswald, Greifswald, Germany
- * E-mail:
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10
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Kaya Z, Yayla M, Cinar I, Celebi D, Toktay E, Bayraktutan Z, Bilici D. Effect of Montelukast, a Cysteinyl Leukotriene Receptor-1 Antagonist, on a Rat Model of Acute Bacterial Sinonasal Inflammation. Am J Rhinol Allergy 2019; 33:559-566. [PMID: 31129976 DOI: 10.1177/1945892419852576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Aim This study aimed to investigate montelukast (MONT), a leukotriene receptor antagonist, as a potential treatment protocol and/or supportive therapy against acute bacterial sinonasal inflammation by histopathological and molecular analyses. Material and Methods A total of 30 rats were used in the study. The nasal dorsum was sterilized, and gelatin sponges were inserted into the right nasal cavities. The nostrils were then inoculated with Staphylococcus aureus (SA) for rhinosinusitis (RS) induction. Rats were treated once daily for 7 days with an injection of saline, either cefazolin sodium (CEFA) or MONT. Tissue samples were collected for examination. Results To evaluate whether CEFA and MONT were able to attenuate the SA-induced nasal inflammation, we analyzed the proinflammatory cytokine levels in the nasal tissue of rats by real-time polymerase chain reaction (PCR). The inflammatory cytokines tumor necrosis factor-α ( P ≤ .05) and interleukin-1α (IL-1α) ( P ≤ .05) increased in the SA-induced group, when compared with the healthy control. MONT treatment significantly reversed these elevations, especially IL-1α messenger RNA expression levels induced by SA. Also, CEFA administration significantly changed the proinflammatory cytokine levels when compared to the SA group, but this effect was not as strong as MONT. Also, histopathological findings supported the beneficial effects of MONT. Conclusion This study histopathologically and molecularly showed that MONT significantly ameliorated the SA-associated sinonasal inflammatory reaction, both alone and in combination with CEFA. These results may suggest that MONT may block the inflammatory reaction underlying RS even more significantly by antioxidative or anti-inflammatory effects. This study suggests MONT as a future potential therapeutic agent for RS treatment.
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Affiliation(s)
- Zülküf Kaya
- 1 Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine, Ataturk University, Erzurum, Turkey
| | - Muhammed Yayla
- 2 Department of Pharmacology, Faculty of Medicine, Kafkas University, Kars, Turkey
| | - Irfan Cinar
- 2 Department of Pharmacology, Faculty of Medicine, Kafkas University, Kars, Turkey
| | - Demet Celebi
- 3 Department of Microbiology, Faculty of Veterinary, Ataturk University, Erzurum, Turkey
| | - Erdem Toktay
- 4 Department of Histology and Embryology, Faculty of Medicine, Ataturk University, Erzurum, Turkey
| | - Zafer Bayraktutan
- 5 Department of Biochemistry, Faculty of Pharmacy, Ataturk University, Erzurum, Turkey
| | - Dilek Bilici
- 6 Department of Microbiology, Erzurum Training and Research Hospital, Erzurum, Turkey
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11
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Kubickova B, Laboha P, Hildebrandt JP, Hilscherová K, Babica P. Effects of cylindrospermopsin on cultured immortalized human airway epithelial cells. CHEMOSPHERE 2019; 220:620-628. [PMID: 30597370 DOI: 10.1016/j.chemosphere.2018.12.157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 12/19/2018] [Accepted: 12/21/2018] [Indexed: 06/09/2023]
Abstract
Anthropogenic eutrophication of freshwater bodies increases the occurrence of toxic cyanobacterial blooms. The cyanobacterial toxin cylindrospermopsin (CYN) is detected in the environment with increasing frequency, driving the scientific effort to assess emerging health risks from CYN-producing blooms. Oral exposure to CYN results primarily in hepatotoxicity. Nevertheless, extrahepatic manifestations of CYN toxicity have been reported. Furthermore, cyanotoxins have been detected in aerosols and dust particles, suggesting potential toxic effects in the respiratory tract. To assess the susceptibility of airway epithelia towards cyanotoxins, monolayers of immortalized human bronchial epithelial cells HBE1 and 16HBE14o- were exposed to a concentration range of 0.1-10 μM CYN. Cytotoxic endpoints were assessed as morphologic alterations, resazurin reduction capacity, esterase activity, neutral red uptake, and by impedimetric real-time cell analysis. Depending on the endpoint assessed, EC50 values ranged between 0.7 and 1.8 μM (HBE1) and 1.6-4.8 μM (16HBE14o-). To evaluate alterations of other cellular events by subcytotoxic concentration of CYN (1 μM), phosphorylation of mitogen-activated protein kinases ERK and p38 was determined. Only a slight increase in p38 phosphorylation was induced by CYN in HBE1 cell line after 48 h, while activities of both ERK1/2 and p38 gradually and significantly increased in 16HBE14o- cells during 8-48 h exposure. This study suggests possible hazards of inhalation CYN exposures, which may severely impact the integrity of airway epithelia and epithelial cell signaling. Further research of CYN-induced toxicity and underlying mechanisms is needed, as well as more data on environmental concentrations of cyanotoxins in aerosols for exposure assessment.
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Affiliation(s)
- Barbara Kubickova
- Masaryk University, Faculty of Science, RECETOX, Kamenice 753/5, 625 00 Brno, Czech Republic.
| | - Petra Laboha
- Masaryk University, Faculty of Science, RECETOX, Kamenice 753/5, 625 00 Brno, Czech Republic.
| | - Jan-Peter Hildebrandt
- University of Greifswald, Zoological Institute and Museum, Department of Animal Physiology and Biochemistry, Felix-Hausdorff-Str. 1, 17489 Greifswald, Germany.
| | - Klara Hilscherová
- Masaryk University, Faculty of Science, RECETOX, Kamenice 753/5, 625 00 Brno, Czech Republic.
| | - Pavel Babica
- Masaryk University, Faculty of Science, RECETOX, Kamenice 753/5, 625 00 Brno, Czech Republic.
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12
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Ziesemer S, Möller N, Nitsch A, Müller C, Beule AG, Hildebrandt JP. Sphingomyelin Depletion from Plasma Membranes of Human Airway Epithelial Cells Completely Abrogates the Deleterious Actions of S. aureus Alpha-Toxin. Toxins (Basel) 2019; 11:toxins11020126. [PMID: 30791542 PMCID: PMC6409578 DOI: 10.3390/toxins11020126] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/12/2019] [Accepted: 02/15/2019] [Indexed: 12/16/2022] Open
Abstract
Interaction of Staphylococcus aureus alpha-toxin (hemolysin A, Hla) with eukaryotic cell membranes is mediated by proteinaceous receptors and certain lipid domains in host cell plasma membranes. Hla is secreted as a 33 kDa monomer that forms heptameric transmembrane pores whose action compromises maintenance of cell shape and epithelial tightness. It is not exactly known whether certain membrane lipid domains of host cells facilitate adhesion of Ha monomers, oligomerization, or pore formation. We used sphingomyelinase (hemolysin B, Hlb) expressed by some strains of staphylococci to pre-treat airway epithelial model cells in order to specifically decrease the sphingomyelin (SM) abundance in their plasma membranes. Such a pre-incubation exclusively removed SM from the plasma membrane lipid fraction. It abrogated the formation of heptamers and prevented the formation of functional transmembrane pores. Hla exposure of rHlb pre-treated cells did not result in increases in [Ca2+]i, did not induce any microscopically visible changes in cell shape or formation of paracellular gaps, and did not induce hypo-phosphorylation of the actin depolymerizing factor cofilin as usual. Removal of sphingomyelin from the plasma membranes of human airway epithelial cells completely abrogates the deleterious actions of Staphylococcus aureus alpha-toxin.
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Affiliation(s)
- Sabine Ziesemer
- University of Greifswald, Animal Physiology and Biochemistry, Felix Hausdorff-Straße 1, D-17489 Greifswald, Germany.
| | - Nils Möller
- University of Greifswald, Animal Physiology and Biochemistry, Felix Hausdorff-Straße 1, D-17489 Greifswald, Germany.
| | - Andreas Nitsch
- University of Greifswald, Animal Physiology and Biochemistry, Felix Hausdorff-Straße 1, D-17489 Greifswald, Germany.
| | - Christian Müller
- University of Greifswald, Animal Physiology and Biochemistry, Felix Hausdorff-Straße 1, D-17489 Greifswald, Germany.
| | - Achim G Beule
- Department of Otorhinolaryngology, University Hospital, Münster, Germany and Department of Otorhinolaryngology, Head and Neck Surgery, Greifswald University Hospital, D-17489 Greifswald, Germany.
| | - Jan-Peter Hildebrandt
- University of Greifswald, Animal Physiology and Biochemistry, Felix Hausdorff-Straße 1, D-17489 Greifswald, Germany.
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13
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Valera FCP, Ruffin M, Adam D, Maillé É, Ibrahim B, Berube J, Rousseau S, Brochiero E, Desrosiers MY. Staphylococcus aureus impairs sinonasal epithelial repair: Effects in patients with chronic rhinosinusitis with nasal polyps and control subjects. J Allergy Clin Immunol 2018; 143:591-603.e3. [PMID: 29935218 DOI: 10.1016/j.jaci.2018.05.035] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 05/07/2018] [Accepted: 05/19/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND The effect of Staphylococcus aureus on nasal epithelial repair has never been assessed in patients with chronic rhinosinusitis with nasal polyps (CRSwNP). OBJECTIVE This study aimed to determine whether (1) nasal epithelial cell cultures from patients with CRSwNP and control subjects repair differently; (2) S aureus exoproducts compromise nasal epithelial repair; (3) S aureus alters lamellipodial dynamics; and (4) deleterious effects could be counteracted by the Rho-associated coiled-coil kinase inhibitor Y-27632. METHODS Primary nasal epithelial cells (pNECs) collected during surgeries were cultured and injured under 3 conditions: (1) basal conditions, (2) exposed to S aureus exoproducts, and (3) exposed to S aureus exoproducts and Y-27632. Epithelial repair, lamellipodial dynamics, and cytoskeletal organization were assessed. RESULTS Under basal conditions, pNEC cultures from patients with CRSwNP presented significantly lower repair rates and reduced lamellipodial protrusion length and velocity than those from control subjects. S aureus exoproducts significantly decreased repair rates and protrusion dynamics in both control subjects and patients with CRSwNP; however, the effect of S aureus on cell protrusions was more sustained over time in patients with CRSwNP. Under basal conditions, immunofluorescence assays showed significantly reduced percentages of cells with lamellipodia at the wound edge in patients with CRSwNP compared with control subjects. S aureus altered cell polarity and decreased the percentage of cells with lamellipodia in both groups. Finally, Y-27632 prevented the deleterious effects of S aureus exoproducts on CRSwNP repair rates, as well as on lamellipodial dynamics and formation. CONCLUSIONS S aureus exoproducts significantly alter epithelial repair and lamellipodial dynamics on pNECs, and this impairment was more pronounced in patients with CRSwNP. Importantly, Y-27632 restored epithelial repair and lamellipodial dynamics in the presence of S aureus exoproducts.
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Affiliation(s)
- Fabiana C P Valera
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada; Division of Otorhinolaryngology, Ribeirão Preto Medical School, University of São Paulo (FMRP-USP), Ribeirão Preto, Brazil
| | - Manon Ruffin
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada; Département de Médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Damien Adam
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada; Département de Médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Émilie Maillé
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Badr Ibrahim
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada; Department of Otolaryngology, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, Quebec, Canada
| | - Julie Berube
- Meakins-Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Simon Rousseau
- Meakins-Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Emmanuelle Brochiero
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada; Département de Médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Martin Y Desrosiers
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada; Department of Otolaryngology, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, Quebec, Canada.
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14
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Moyano AJ, Racca AC, Soria G, Saka HA, Andreoli V, Smania AM, Sola C, Bocco JL. c-Jun Proto-Oncoprotein Plays a Protective Role in Lung Epithelial Cells Exposed to Staphylococcal α-Toxin. Front Cell Infect Microbiol 2018; 8:170. [PMID: 29888211 PMCID: PMC5981160 DOI: 10.3389/fcimb.2018.00170] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 05/03/2018] [Indexed: 12/17/2022] Open
Abstract
c-Jun is a member of the early mammalian transcriptional regulators belonging to the AP-1 family, which participates in a wide range of cellular processes such as proliferation, apoptosis, tumorigenesis, and differentiation. Despite its established role in cell survival upon stress, its participation in the stress response induced by bacterial infections has been poorly investigated. To study the potential role of c-Jun in this context we choose the widely studied α-toxin produced by Staphylococcus aureus, a pore-forming toxin that is a critical virulence factor in the pathogenesis of these bacteria. We analyzed the effect of α-toxin treatment in the activation, expression, and protein levels of c-Jun in A549 lung epithelial cells. Furthermore, we explored the role of c-Jun in the cellular fate after exposure to α-toxin. Our results show that staphylococcal α-toxin per se is able to activate c-Jun by inducing phosphorylation of its Serine 73 residue. Silencing of the JNK (c-Jun N-terminal Kinase) signaling pathway abrogated most of this activation. On the contrary, silencing of the ERK (Extracellular Signal-Regulated Kinase) pathway exacerbated this response. Intriguingly, while the exposure to α-toxin induced a marked increase in the levels of c-Jun transcripts, c-Jun protein levels noticeably decreased in the same time-frame as a consequence of active proteolytic degradation through the proteasome-dependent pathway. In addition, we established that c-Jun promoted cell survival when cells were challenged with α-toxin. Similarly, c-Jun phosphorylation was also induced in cells upon intoxication with the cytolysin produced by Vibrio cholerae in a JNK-dependent manner, suggesting that c-Jun-JNK axis would be a conserved responsive cellular pathway to pore-forming toxins. This study contributes to understanding the role of the multifaceted c-Jun proto-oncoprotein in cell response to bacterial pore-forming toxins, positioning it as a relevant component of the complex early machinery mounted to deal with staphylococcal infections.
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Affiliation(s)
- Alejandro J Moyano
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Ana C Racca
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Gastón Soria
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Héctor A Saka
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Verónica Andreoli
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andrea M Smania
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Química Biológica de Córdoba, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Claudia Sola
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - José L Bocco
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
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15
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Bartoszewski R, Matalon S, Collawn JF. Ion channels of the lung and their role in disease pathogenesis. Am J Physiol Lung Cell Mol Physiol 2017; 313:L859-L872. [PMID: 29025712 PMCID: PMC5792182 DOI: 10.1152/ajplung.00285.2017] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/03/2017] [Accepted: 10/03/2017] [Indexed: 12/16/2022] Open
Abstract
Maintenance of normal epithelial ion and water transport in the lungs includes providing a thin layer of surface liquid that coats the conducting airways. This airway surface liquid is critical for normal lung function in a number of ways but, perhaps most importantly, is required for normal mucociliary clearance and bacterial removal. Preservation of the appropriate level of hydration, pH, and viscosity for the airway surface liquid requires the proper regulation and function of a battery of different types of ion channels and transporters. Here we discuss how alterations in ion channel/transporter function often lead to lung pathologies.
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Affiliation(s)
- Rafal Bartoszewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - Sadis Matalon
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
- Department of Cell, Developmental, and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
- Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
- Gregory Fleming James Cystic Fibrosis Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama;
- Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
- Gregory Fleming James Cystic Fibrosis Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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16
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Pietrocola G, Nobile G, Rindi S, Speziale P. Staphylococcus aureus Manipulates Innate Immunity through Own and Host-Expressed Proteases. Front Cell Infect Microbiol 2017; 7:166. [PMID: 28529927 PMCID: PMC5418230 DOI: 10.3389/fcimb.2017.00166] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 04/18/2017] [Indexed: 01/29/2023] Open
Abstract
Neutrophils, complement system and skin collectively represent the main elements of the innate immune system, the first line of defense of the host against many common microorganisms. Bacterial pathogens have evolved strategies to counteract all these defense activities. Specifically, Staphylococcus aureus, a major human pathogen, secretes a variety of immune evasion molecules including proteases, which cleave components of the innate immune system or disrupt the integrity of extracellular matrix and intercellular connections of tissues. Additionally, S. aureus secretes proteins that can activate host zymogens which, in turn, target specific defense components. Secreted proteins can also inhibit the anti-bacterial function of neutrophils or complement system proteases, potentiating S. aureus chances of survival. Here, we review the current understanding of these proteases and modulators of host proteases in the functioning of innate immunity and describe the importance of these mechanisms in the pathology of staphylococcal diseases.
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Affiliation(s)
- Giampiero Pietrocola
- Unit of Biochemistry, Department of Molecular Medicine, University of PaviaPavia, Italy
| | - Giulia Nobile
- Unit of Biochemistry, Department of Molecular Medicine, University of PaviaPavia, Italy
| | - Simonetta Rindi
- Unit of Biochemistry, Department of Molecular Medicine, University of PaviaPavia, Italy
| | - Pietro Speziale
- Unit of Biochemistry, Department of Molecular Medicine, University of PaviaPavia, Italy
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17
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Seilie ES, Bubeck Wardenburg J. Staphylococcus aureus pore-forming toxins: The interface of pathogen and host complexity. Semin Cell Dev Biol 2017; 72:101-116. [PMID: 28445785 DOI: 10.1016/j.semcdb.2017.04.003] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 03/22/2017] [Accepted: 04/18/2017] [Indexed: 12/20/2022]
Abstract
Staphylococcus aureus is a prominent human pathogen capable of infecting a variety of host species and tissue sites. This versatility stems from the pathogen's ability to secrete diverse host-damaging virulence factors. Among these factors, the S. aureus pore-forming toxins (PFTs) α-toxin and the bicomponent leukocidins, have garnered much attention for their ability to lyse cells at low concentrations and modulate disease severity. Although many of these toxins were discovered nearly a century ago, their host cell specificities have only been elucidated over the past five to six years, starting with the discovery of the eukaryotic receptor for α-toxin and rapidly followed by identification of the leukocidin receptors. The identification of these receptors has revealed the species- and cell type-specificity of toxin binding, and provided insight into non-lytic effects of PFT intoxication that contribute to disease pathogenesis.
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Affiliation(s)
- E Sachiko Seilie
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, United States; Department of Microbiology, The University of Chicago, Chicago, IL 60637, United States
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18
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Baaske R, Richter M, Möller N, Ziesemer S, Eiffler I, Müller C, Hildebrandt JP. ATP Release from Human Airway Epithelial Cells Exposed to Staphylococcus aureus Alpha-Toxin. Toxins (Basel) 2016; 8:toxins8120365. [PMID: 27929417 PMCID: PMC5198559 DOI: 10.3390/toxins8120365] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 11/30/2016] [Accepted: 12/01/2016] [Indexed: 11/20/2022] Open
Abstract
Airway epithelial cells reduce cytosolic ATP content in response to treatment with S. aureus alpha-toxin (hemolysin A, Hla). This study was undertaken to investigate whether this is due to attenuated ATP generation or to release of ATP from the cytosol and extracellular ATP degradation by ecto-enzymes. Exposure of cells to rHla did result in mitochondrial calcium uptake and a moderate decline in mitochondrial membrane potential, indicating that ATP regeneration may have been attenuated. In addition, ATP may have left the cells through transmembrane pores formed by the toxin or through endogenous release channels (e.g., pannexins) activated by cellular stress imposed on the cells by toxin exposure. Exposure of cells to an alpha-toxin mutant (H35L), which attaches to the host cell membrane but does not form transmembrane pores, did not induce ATP release from the cells. The Hla-mediated ATP-release was completely blocked by IB201, a cyclodextrin-inhibitor of the alpha-toxin pore, but was not at all affected by inhibitors of pannexin channels. These results indicate that, while exposure of cells to rHla may somewhat reduce ATP production and cellular ATP content, a portion of the remaining ATP is released to the extracellular space and degraded by ecto-enzymes. The release of ATP from the cells may occur directly through the transmembrane pores formed by alpha-toxin.
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Affiliation(s)
- Romina Baaske
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Mandy Richter
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Nils Möller
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Sabine Ziesemer
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Ina Eiffler
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Christian Müller
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Jan-Peter Hildebrandt
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
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