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Wanford JJ, Odendall C. Ca 2+-calmodulin signalling at the host-pathogen interface. Curr Opin Microbiol 2023; 72:102267. [PMID: 36716574 DOI: 10.1016/j.mib.2023.102267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/19/2022] [Accepted: 01/04/2023] [Indexed: 01/29/2023]
Abstract
Multiple eukaryotic cell processes are modulated by calcium ions (Ca2+). As such, Ca2+ is emerging as a crucial regulator of innate immunity in multicellular organisms. In particular, recent studies have identified roles of Ca2+ signalling at the host-bacteria interface. Following microbial exposure, Ca2+ signals mobilised from the extracellular milieu or intracellular stores are transduced into cell physiological responses. However, during infection with host-adapted pathogens, Ca2+ signals are often atypical, due to the activities of virulence factors, with varied consequences for both the pathogen and the host cell. In this review, we describe the Ca2+-dependent host factors regulating antibacterial immunity, in addition to bacterial effectors that promote, inhibit, or co-opt Ca2+-calmodulin signalling to promote infection.
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Affiliation(s)
- Joseph J Wanford
- School of Immunology and Microbial Sciences, Kings College London, London, UK
| | - Charlotte Odendall
- School of Immunology and Microbial Sciences, Kings College London, London, UK.
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2
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Staropoli A, Cuomo P, Salvatore MM, De Tommaso G, Iuliano M, Andolfi A, Tenore GC, Capparelli R, Vinale F. Harzianic Acid Activity against Staphylococcus aureus and Its Role in Calcium Regulation. Toxins (Basel) 2023; 15:toxins15040237. [PMID: 37104175 PMCID: PMC10146698 DOI: 10.3390/toxins15040237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 04/28/2023] Open
Abstract
Staphylococcus aureus is a Gram-positive bacterium, which can be found, as a commensal microorganism, on the skin surface or in the nasal mucosa of the human population. However, S. aureus may become pathogenic and cause severe infections, especially in hospitalized patients. As an opportunistic pathogen, in fact, S. aureus interferes with the host Ca2+ signaling, favoring the spread of the infection and tissue destruction. The identification of novel strategies to restore calcium homeostasis and prevent the associated clinical outcomes is an emerging challenge. Here, we investigate whether harzianic acid, a bioactive metabolite derived from fungi of the genus Trichoderma, could control S. aureus-induced Ca2+ movements. First, we show the capability of harzianic acid to complex calcium divalent cations, using mass spectrometric, potentiometric, spectrophotometric, and nuclear magnetic resonance techniques. Then, we demonstrate that harzianic acid significantly modulates Ca2+ increase in HaCaT (human keratinocytes) cells incubated with S. aureus. In conclusion, this study suggests harzianic acid as a promising therapeutical alternative against diseases associated with Ca2+ homeostasis alteration.
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Affiliation(s)
- Alessia Staropoli
- Institute for Sustainable Plant Protection, National Research Council, 80055 Portici, Italy
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
| | - Paola Cuomo
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
| | - Maria Michela Salvatore
- Institute for Sustainable Plant Protection, National Research Council, 80055 Portici, Italy
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
| | - Gaetano De Tommaso
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
| | - Mauro Iuliano
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
| | - Anna Andolfi
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
- BAT Center-Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Naples Federico II, 80055 Portici, Italy
| | - Gian Carlo Tenore
- Department of Pharmacy, University of Naples Federico II, 80131 Naples, Italy
| | - Rosanna Capparelli
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
| | - Francesco Vinale
- BAT Center-Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Naples Federico II, 80055 Portici, Italy
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, 80137 Naples, Italy
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3
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Chen Y, Li L, Wang C, Zhang Y, Zhou Y. Necrotizing Pneumonia in Children: Early Recognition and Management. J Clin Med 2023; 12:jcm12062256. [PMID: 36983257 PMCID: PMC10051935 DOI: 10.3390/jcm12062256] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/27/2023] [Accepted: 03/02/2023] [Indexed: 03/17/2023] Open
Abstract
Necrotizing pneumonia (NP) is an uncommon complicated pneumonia with an increasing incidence. Early recognition and timely management can bring excellent outcomes. The diagnosis of NP depends on chest computed tomography, which has radiation damage and may miss the optimal treatment time. The present review aimed to elaborate on the reported predictors for NP. The possible pathogenesis of Streptococcus pneumoniae, Staphylococcus aureus, Mycoplasma pneumoniae and coinfection, clinical manifestations and management were also discussed. Although there is still a long way for these predictors to be used in clinical, it is necessary to investigate early predictors for NP in children.
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Affiliation(s)
- Yuanyuan Chen
- Department of Pulmonology, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou 310052, China
- National Clinical Research Center for Child Health, Hangzhou 310052, China
| | - Lanxin Li
- Department of Pulmonology, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou 310052, China
- National Clinical Research Center for Child Health, Hangzhou 310052, China
| | - Chenlu Wang
- Department of Pulmonology, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou 310052, China
- National Clinical Research Center for Child Health, Hangzhou 310052, China
| | - Yuanyuan Zhang
- Department of Pulmonology, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou 310052, China
- National Clinical Research Center for Child Health, Hangzhou 310052, China
- Correspondence: (Y.Z.); (Y.Z.)
| | - Yunlian Zhou
- Department of Pulmonology, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou 310052, China
- National Clinical Research Center for Child Health, Hangzhou 310052, China
- Correspondence: (Y.Z.); (Y.Z.)
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4
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Gauron MC, Newton AC, Colombo MI. PKCα Is Recruited to Staphylococcus aureus-Containing Phagosomes and Impairs Bacterial Replication by Inhibition of Autophagy. Front Immunol 2021; 12:662987. [PMID: 33815423 PMCID: PMC8013776 DOI: 10.3389/fimmu.2021.662987] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/03/2021] [Indexed: 11/24/2022] Open
Abstract
Hijacking the autophagic machinery is a key mechanism through which invasive pathogens such as Staphylococcus aureus replicate in their host cells. We have previously demonstrated that the bacteria replicate in phagosomes labeled with the autophagic protein LC3, before escaping to the cytoplasm. Here, we show that the Ca2+-dependent PKCα binds to S. aureus-containing phagosomes and that α-hemolysin, secreted by S. aureus, promotes this recruitment of PKCα to phagosomal membranes. Interestingly, the presence of PKCα prevents the association of the autophagic protein LC3. Live cell imaging experiments using the PKC activity reporter CKAR reveal that treatment of cells with S. aureus culture supernatants containing staphylococcal secreted factors transiently activates PKC. Functional studies reveal that overexpression of PKCα causes a marked inhibition of bacterial replication. Taken together, our data identify enhancing PKCα activity as a potential approach to inhibit S. aureus replication in mammalian cells.
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Affiliation(s)
- Maria Celeste Gauron
- Laboratorio de Mecanismos Moleculares Implicados en el Tráfico Vesicular y la Autofagia-Instituto de Histología y Embriología (IHEM)- Universidad Nacional de Cuyo, CONICET- Facultad de Ciencias Médicas, Mendoza, Argentina.,Department of Pharmacology, University of California San Diego, La Jolla, CA, United States
| | - Alexandra C Newton
- Department of Pharmacology, University of California San Diego, La Jolla, CA, United States
| | - María Isabel Colombo
- Laboratorio de Mecanismos Moleculares Implicados en el Tráfico Vesicular y la Autofagia-Instituto de Histología y Embriología (IHEM)- Universidad Nacional de Cuyo, CONICET- Facultad de Ciencias Médicas, Mendoza, Argentina
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5
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Dahou S, Smahi MCE, Nouari W, Dahmani Z, Benmansour S, Ysmail-Dahlouk L, Miliani M, Yebdri F, Fakir N, Laoufi MY, Chaib-Draa M, Tourabi A, Aribi M. L-Threoascorbic acid treatment promotes S. aureus-infected primary human endothelial cells survival and function, as well as intracellular bacterial killing, and immunomodulates the release of IL-1β and soluble ICAM-1. Int Immunopharmacol 2021; 95:107476. [PMID: 33676147 DOI: 10.1016/j.intimp.2021.107476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Vitamin C (ascorbic acid, AscH2) has been shown to enhance immunity. Here, we studied its immunomodulatory effect on human endothelial cells (ECs) during S. aureus infection. MATERIALS AND METHODS The ex vivo effects of AscH2 were performed on primary human umbilical vein endothelial cells (HUVECs) infected or not with S. aureus. RESULTS AscH2 treatment induced a marked downregulation of nitric oxide (NO) production and a moderate upregulation of arginase activity in S. aureus-infected HUVECs (respectively, p < 0.05 and p > 0.05). Although the upregulated release levels of soluble intercellular adhesion molecular 1 (sICAM-1/sCD54) and sE-selectin (sCD62E) molecules were not significantly different between treated and untreated S. aureus-infected HUVECs, AscH2 treatment induced reversing effect on sICAM-1 release when comparing to uninfected control HUVECs. Moreover, AscH2 treatment appears to have a significant effect on preventing HUVEC necrosis induced by S. aureus infection (p < 0.05). Furthermore, AscH2 treatment induced a significant upregulation of cell protective redox biomarker in S. aureus-infected, as shown by superoxide dismutase (SOD) activity (p < 0.05), but not by catalase activity (p > 0.05). Additionally, S. aureus infection markedly downregulated total bound calcium ions (bCa2+) levels as compared to control HUVECs, whereas, AscH2 treatment induced a slight upregulation of bCa2+ levels in infected HUVECs as compared to infected and untreated HUVECs (p > 0.05). On the other hand, AscH2 treatment downregulated increased total cellular cholesterol content (tccCHOL) levels in HUVECs induced by S. aureus infection (p < 0.05). In addition, AscH2 treatment markedly reversed S. aureus effect on upregulation of intracellular glucose (iGLU) levels within infected HUVECs (p < 0.05). Moreover, AscH2 treatment significantly downregulated S. aureus growth (p < 0.05), and significantly upregulated bacterial internalization and intracellular killing by HUVECs (p < 0.05), as well as their cell cycle activation (p < 0.01). Finally, AscH2 treatment has a slight effect on the production of interleukin 6 (IL-6), but induced a marked downregulation of that of IL-1β in S. aureus-infected HUVECs (respectively, p > 0.05, and p < 0.05). CONCLUSIONS Our outcomes demonstrated that, during S. aureus infection, AscH2 treatment promotes human ECs survival and function, as well as prevents inflammatory response exacerbation, while inducing bactericidal activity.
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Affiliation(s)
- Sara Dahou
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Mohammed Chems-Eddine Smahi
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria; Neonatal Department of Specialized Maternal and Child Hospital of Tlemcen, 13000, Tlemcen, Algeria
| | - Wafa Nouari
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Zoheir Dahmani
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Souheila Benmansour
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria; Neonatal Department of Specialized Maternal and Child Hospital of Tlemcen, 13000, Tlemcen, Algeria
| | - Lamia Ysmail-Dahlouk
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Maroua Miliani
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Fadela Yebdri
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Nassima Fakir
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Mohammed Yassine Laoufi
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria; Neonatal Department of Specialized Maternal and Child Hospital of Tlemcen, 13000, Tlemcen, Algeria
| | - Mouad Chaib-Draa
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Amina Tourabi
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria
| | - Mourad Aribi
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, 13000 Tlemcen, Algeria.
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6
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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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7
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Verma C, Ankush KR, Anang V, Tiwari BK, Singh A, Surender Kumar Saraswati S, Shariff M, Natarajan K. Calcium Dynamics Regulate Protective Responses and Growth of Staphylococcus aureus in Macrophages. Biomol Concepts 2020; 11:230-239. [PMID: 33726488 DOI: 10.1515/bmc-2020-0021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Staphylococcus aureus (S. aureus) is a gram-positive bacteria, which causes various fatal respiratory infections including pneumonia. The emergence of Methicillin-Resistance Staphylococcus aureus (MRSA) demands a thorough understanding of host-pathogen interactions. Here we report the role of calcium in regulating defence responses of S. aureus in macrophages. Regulating calcium fluxes in cells by different routes differentially governs the expression of T cell costimulatory molecule CD80 and Th1 promoting IL-12 receptor. Inhibiting calcium influx from extracellular medium increased expression of IFN-γ and IL-10 while blocking calcium release from the intracellular stores inhibited TGF-β levels. Blocking voltage-gated calcium channels (VGCC) inhibited the expression of multiple cytokines. While VGCC regulated the expression of apoptosis protein Bax, extracellular calcium-regulated the expression of Cytochrome-C. Similarly, VGCC regulated the expression of autophagy initiator Beclin-1. Blocking VGCC or calcium release from intracellular stores promoted phagosome-lysosome fusion, while activating VGCC inhibited phagosomelysosome fusion. Finally, calcium homeostasis regulated intracellular growth of Staphylococcus, although using different mechanisms. While blocking extracellular calcium influx seems to rely on IFN-γ and IL-12Rβ receptor mediated reduction in bacterial survival, blocking either intracellular calcium release or via VGCC route seem to rely on enhanced autophagy mediated reduction of intracellular bacterial survival. These results point to fine-tuning of defence responses by routes of calcium homeostasis.
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Affiliation(s)
- Chaitenya Verma
- Infectious Disease Immunology Lab, Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110007, India.,Department of Pathology, Wexner Medical Center,The Ohio State University, OH-43210, USA
| | - Kumar Rana Ankush
- Infectious Disease Immunology Lab, Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110007, India
| | - Vandana Anang
- Infectious Disease Immunology Lab, Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110007, India
| | - Brijendra K Tiwari
- Infectious Disease Immunology Lab, Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110007, India
| | - Aayushi Singh
- Infectious Disease Immunology Lab, Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110007, India
| | | | - Malini Shariff
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 110007, India
| | - Krishnamurthy Natarajan
- Infectious Disease Immunology Lab, Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110007, India
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8
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Abstract
Despite being regarded as an extracellular bacterium, the pathogen Staphylococcus aureus can invade and survive within human cells. The intracellular niche is considered a hideout from the host immune system and antibiotic treatment and allows bacterial proliferation. The opportunistic human pathogen Staphylococcus aureus causes serious infectious diseases that range from superficial skin and soft tissue infections to necrotizing pneumonia and sepsis. While classically regarded as an extracellular pathogen, S. aureus is able to invade and survive within human cells. Host cell exit is associated with cell death, tissue destruction, and the spread of infection. The exact molecular mechanism employed by S. aureus to escape the host cell is still unclear. In this study, we performed a genome-wide small hairpin RNA (shRNA) screen and identified the calcium signaling pathway as being involved in intracellular infection. S. aureus induced a massive cytosolic Ca2+ increase in epithelial host cells after invasion and intracellular replication of the pathogen. This was paralleled by a decrease in endoplasmic reticulum Ca2+ concentration. Additionally, calcium ions from the extracellular space contributed to the cytosolic Ca2+ increase. As a consequence, we observed that the cytoplasmic Ca2+ rise led to an increase in mitochondrial Ca2+ concentration, the activation of calpains and caspases, and eventually to cell lysis of S. aureus-infected cells. Our study therefore suggests that intracellular S. aureus disturbs the host cell Ca2+ homeostasis and induces cytoplasmic Ca2+ overload, which results in both apoptotic and necrotic cell death in parallel or succession.
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9
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Nava AR, Mauricio N, Sanca AJ, Domínguez DC. Evidence of Calcium Signaling and Modulation of the LmrS Multidrug Resistant Efflux Pump Activity by Ca 2 + Ions in S. aureus. Front Microbiol 2020; 11:573388. [PMID: 33193178 PMCID: PMC7642317 DOI: 10.3389/fmicb.2020.573388] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/14/2020] [Indexed: 12/19/2022] Open
Abstract
Calcium ions (Ca2+) play a pivotal role in eukaryote cell signaling and regulate many physiological functions. Although a similar role for Ca2+ in prokaryotes has been difficult to demonstrate, there is increasing evidence for Ca2+ as a cell regulator in bacteria. The purpose of this study was to investigate Ca2+ signaling and the effect of Ca2+ on the Staphylococcus aureus multidrug resistant efflux pump LmrS. We hypothesized that antibiotics act by increasing Ca2+ concentrations, which in turn enhance the efflux activity of LmrS. These Ca2+ transients were measured by luminometry in response to various antibiotics by using the photoprotein aequorin reconstituted within live bacterial cells. Efflux associated with LmrS was measured by the increase in fluorescence due to the loss of ethidium bromide (EtBr) from both S. aureus cells and from E. coli cells in which the lmrs gene of S. aureus was expressed. We found that addition of antibiotics to cells generated unique cytosolic Ca2+ transients and that addition of CaCl2 to cells enhanced EtBr efflux whereas addition of Ca2+ chelators or efflux pump inhibitors significantly decreased EtBr efflux from cells. We conclude that antibiotics induce a Ca2+ mediated response through transients in cytosolic Ca2+, which then stimulates LmrS efflux pump.
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Affiliation(s)
- Amy R Nava
- Department of Interdisciplinary Health Sciences, The University of Texas at El Paso, El Paso, TX, United States
| | - Natalia Mauricio
- Biology Department, El Paso Community College, El Paso, TX, United States
| | - Angel J Sanca
- Biological Sciences Department, The University of Texas at El Paso, El Paso, TX, United States
| | - Delfina C Domínguez
- Department of Interdisciplinary Health Sciences, The University of Texas at El Paso, El Paso, TX, United States.,Clinical Laboratory Science Program/Department of Public Health Sciences, The University of Texas at El Paso, El Paso, TX, United States
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10
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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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11
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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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12
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Clostridium perfringens Epsilon-Toxin Impairs the Barrier Function in MDCK Cell Monolayers in a Ca 2+-Dependent Manner. Toxins (Basel) 2020; 12:toxins12050286. [PMID: 32365779 PMCID: PMC7291203 DOI: 10.3390/toxins12050286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/21/2020] [Accepted: 04/28/2020] [Indexed: 12/27/2022] Open
Abstract
Epsilon-toxin produced by Clostridium perfringens significantly contributes to the pathogeneses of enterotoxemia in ruminants and multiple sclerosis in humans. Epsilon-toxin forms a heptameric oligomer in the host cell membrane, promoting cell disruption. Here, we investigate the effect of epsilon-toxin on epithelial barrier functions. Epsilon-toxin impairs the barrier integrity of Madin-Darby Canine Kidney (MDCK) cells, as demonstrated by decreased transepithelial electrical resistance (TEER), increased paracellular flux marker permeability, and the decreased cellular localization of junctional proteins, such as occludin, ZO-1, and claudin-1. U73122, an endogenous phospholipase C (PLC) inhibitor, inhibited the decrease in TEER and the increase in the permeability of flux marker induced by epsilon-toxin. The application of epsilon-toxin to MDCK cells resulted in the biphasic formation of 1,2-diacylglycerol (DAG) and inositol-1,4,5-triphosphate (IP3). U73122 blocked the formation of DAG and IP3 induced by the toxin. Epsilon-toxin also specifically activated endogenous PLC-γ1. Epsilon-toxin dose-dependently increased the cytosolic calcium ion concentration ([Ca2+]i). The toxin-induced elevation of [Ca2+]i was inhibited by U73122. Cofilin is a key regulator of actin cytoskeleton turnover and tight-junction (TJ) permeability regulation. Epsilon-toxin caused cofilin dephosphorylation. These results demonstrate that epsilon-toxin induces Ca2+ influx through activating the phosphorylation of PLC-γ1 and then causes TJ opening accompanied by cofilin dephosphorylation.
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13
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Johansson C, Rautelin H, Kaden R. Staphylococcus argenteus and Staphylococcus schweitzeri are cytotoxic to human cells in vitro due to high expression of alpha-hemolysin Hla. Virulence 2020; 10:502-510. [PMID: 31131704 PMCID: PMC6550535 DOI: 10.1080/21505594.2019.1620062] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus argenteus and Staphylococcus schweitzeri are newly identified species of the S. aureus-related complex. S. argenteus, as occurring globally and showing significant prevalence and comparable infection and morbidity rates compared to S. aureus, is becoming clinically important. Whole genome sequencing has revealed the presence of several virulence genes but the molecular mechanisms of S. argenteus infection and virulence are largely unknown. Here, we studied the effect of a previously characterized clinical S. argenteus isolate on human cells in vitro. The clinical isolate, together with the S. argenteus type strain MSHR1132T and the S. schweitzeri type strain FSA084T, had a cytotoxic effect on the cells, which showed necrotic cell death after a few hours of treatment. The protein causing the cytotoxic effect was purified and identified by mass spectrometry as alpha-hemolysin, Hla, which is awell-known pore-forming toxin in S.aureus. The cytotoxic effect could be blocked with an antibody against Hla. S.argenteus showed 12–15 fold higher expression levels of hla at the RNA level and 4–6 fold higher expression levels at the protein level compared to S.aureus. The higher expression levels of hla were supported by higher RNA levels of the regulatory factors sarA and saeR. Also, the RNAIII component of the accessory gene regulator (agr) quorum sensing system was 8,000–10,000 fold higher in the S.argenteus isolates compared to S.aureus. This is the first study on the effect of S.argenteus on ahuman cell line and strengthens the idea of significant virulence of S.argenteus.
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Affiliation(s)
- Cecilia Johansson
- a Clinical Microbiology, Department of Medical Sciences , Uppsala University , Uppsala , Sweden
| | - Hilpi Rautelin
- a Clinical Microbiology, Department of Medical Sciences , Uppsala University , Uppsala , Sweden
| | - René Kaden
- a Clinical Microbiology, Department of Medical Sciences , Uppsala University , Uppsala , Sweden
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14
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von Hoven G, Qin Q, Neukirch C, Husmann M, Hellmann N. Staphylococcus aureus α-toxin: small pore, large consequences. Biol Chem 2020; 400:1261-1276. [PMID: 30951494 DOI: 10.1515/hsz-2018-0472] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/26/2019] [Indexed: 12/14/2022]
Abstract
The small β-pore-forming α-toxin, also termed α-hemolysin or Hla is considered to be an important virulence factor of Staphylococcus aureus. Perforation of the plasma membrane (PM) by Hla leads to uncontrolled flux of ions and water. Already a small number of toxin pores seems to be sufficient to induce complex cellular responses, many of which depend on the efflux of potassium. In this article, we discuss the implications of secondary membrane lesions, for example, by endogenous channels, for Hla-mediated toxicity, for calcium-influx and membrane repair. Activation of purinergic receptors has been proposed to be a major contributor to the lytic effects of various pore forming proteins, but new findings raise doubts that this holds true for Hla. However, the recently discovered cellular pore forming proteins gasdermin D and Mixed lineage kinase domain-like pseudokinase (MLKL) which perforate the PM from the cytosolic side might contribute to both calcium-influx-dependent damage and membrane repair. Activation of endogenous pore forming proteins by Hla above a threshold concentration could explain the apparent dependence of pore characteristics on toxin concentrations. If secondary membrane damage in the aftermath of Hla-attack contributes significantly to overall PM permeability, it might be an interesting target for new therapeutic approaches.
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Affiliation(s)
- Gisela von Hoven
- Institute of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Straße 67, 55131 Mainz, Germany
| | - Qianqian Qin
- Institute of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Straße 67, 55131 Mainz, Germany
| | - Claudia Neukirch
- Institute of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Straße 67, 55131 Mainz, Germany
| | - Matthias Husmann
- Institute of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Straße 67, 55131 Mainz, Germany
| | - Nadja Hellmann
- Institute for Pharmacy and Biochemistry, Johannes Gutenberg-University Mainz, Johann-Joachim Becher-Weg 30, 55128 Mainz, Germany
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15
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King MM, Kayastha BB, Franklin MJ, Patrauchan MA. Calcium Regulation of Bacterial Virulence. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:827-855. [PMID: 31646536 DOI: 10.1007/978-3-030-12457-1_33] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Calcium (Ca2+) is a universal signaling ion, whose major informational role shaped the evolution of signaling pathways, enabling cellular communications and responsiveness to both the intracellular and extracellular environments. Elaborate Ca2+ regulatory networks have been well characterized in eukaryotic cells, where Ca2+ regulates a number of essential cellular processes, ranging from cell division, transport and motility, to apoptosis and pathogenesis. However, in bacteria, the knowledge on Ca2+ signaling is still fragmentary. This is complicated by the large variability of environments that bacteria inhabit with diverse levels of Ca2+. Yet another complication arises when bacterial pathogens invade a host and become exposed to different levels of Ca2+ that (1) are tightly regulated by the host, (2) control host defenses including immune responses to bacterial infections, and (3) become impaired during diseases. The invading pathogens evolved to recognize and respond to the host Ca2+, triggering the molecular mechanisms of adhesion, biofilm formation, host cellular damage, and host-defense resistance, processes enabling the development of persistent infections. In this review, we discuss: (1) Ca2+ as a determinant of a host environment for invading bacterial pathogens, (2) the role of Ca2+ in regulating main events of host colonization and bacterial virulence, and (3) the molecular mechanisms of Ca2+ signaling in bacterial pathogens.
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Affiliation(s)
- Michelle M King
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Biraj B Kayastha
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Michael J Franklin
- Department of Microbiology and Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - Marianna A Patrauchan
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.
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16
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Phobalysin: Fisheye View of Membrane Perforation, Repair, Chemotaxis and Adhesion. Toxins (Basel) 2019; 11:toxins11070412. [PMID: 31315179 PMCID: PMC6669599 DOI: 10.3390/toxins11070412] [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: 05/29/2019] [Revised: 07/04/2019] [Accepted: 07/11/2019] [Indexed: 11/30/2022] Open
Abstract
Phobalysin P (PhlyP, for photobacterial lysin encoded on a plasmid) is a recently described small β-pore forming toxin of Photobacterium damselae subsp. damselae (Pdd). This organism, belonging to the family of Vibrionaceae, is an emerging pathogen of fish and various marine animals, which occasionally causes life-threatening soft tissue infections and septicemia in humans. By using genetically modified Pdd strains, PhlyP was found to be an important virulence factor. More recently, in vitro studies with purified PhlyP elucidated some basic consequences of pore formation. Being the first bacterial small β-pore forming toxin shown to trigger calcium-influx dependent membrane repair, PhlyP has advanced to a revealing model toxin to study this important cellular function. Further, results from co-culture experiments employing various Pdd strains and epithelial cells together with data on other bacterial toxins indicate that limited membrane damage may generally enhance the association of bacteria with target cells. Thereby, remodeling of plasma membrane and cytoskeleton during membrane repair could be involved. In addition, a chemotaxis-dependent attack-and track mechanism influenced by environmental factors like salinity may contribute to PhlyP-dependent association of Pdd with cells. Obviously, a synoptic approach is required to capture the regulatory links governing the interaction of Pdd with target cells. The characterization of Pdd’s secretome may hold additional clues because it may lead to the identification of proteases activating PhlyP’s pro-form. Current findings on PhlyP support the notion that pore forming toxins are not just killer proteins but serve bacteria to fulfill more subtle functions, like accessing their host.
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17
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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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18
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Bouillot S, Reboud E, Huber P. Functional Consequences of Calcium Influx Promoted by Bacterial Pore-Forming Toxins. Toxins (Basel) 2018; 10:toxins10100387. [PMID: 30257425 PMCID: PMC6215193 DOI: 10.3390/toxins10100387] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 09/14/2018] [Accepted: 09/20/2018] [Indexed: 02/06/2023] Open
Abstract
Bacterial pore-forming toxins induce a rapid and massive increase in cytosolic Ca2+ concentration due to the formation of pores in the plasma membrane and/or activation of Ca2+-channels. As Ca2+ is an essential messenger in cellular signaling, a sustained increase in Ca2+ concentration has dramatic consequences on cellular behavior, eventually leading to cell death. However, host cells have adapted mechanisms to protect against Ca2+ intoxication, such as Ca2+ efflux and membrane repair. The final outcome depends upon the nature and concentration of the toxin and on the cell type. This review highlights the repercussions of Ca2+ overload on the induction of cell death, repair mechanisms, cellular adhesive properties, and the inflammatory response.
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Affiliation(s)
- Stéphanie Bouillot
- Université Grenoble Alpes, CNRS ERL5261, CEA BIG-BCI, INSERM UMR1036, Grenoble 38054, France.
| | - Emeline Reboud
- Université Grenoble Alpes, CNRS ERL5261, CEA BIG-BCI, INSERM UMR1036, Grenoble 38054, France.
| | - Philippe Huber
- Université Grenoble Alpes, CNRS ERL5261, CEA BIG-BCI, INSERM UMR1036, Grenoble 38054, France.
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19
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Analysis of Staphylococcus aureus proteins secreted inside infected human epithelial cells. Int J Med Microbiol 2018; 308:664-674. [DOI: 10.1016/j.ijmm.2018.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 05/24/2018] [Accepted: 06/16/2018] [Indexed: 11/22/2022] Open
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20
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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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21
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Ziesemer S, Eiffler I, Schönberg A, Müller C, Hochgräfe F, Beule AG, Hildebrandt JP. Staphylococcus aureusα-Toxin Induces Actin Filament Remodeling in Human Airway Epithelial Model Cells. Am J Respir Cell Mol Biol 2018; 58:482-491. [DOI: 10.1165/rcmb.2016-0207oc] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Sabine Ziesemer
- Animal Physiology and Biochemistry, Zoological Institute, and
| | - Ina Eiffler
- Animal Physiology and Biochemistry, Zoological Institute, and
| | | | | | - Falko Hochgräfe
- Junior Research Group Pathoproteomics, Competence Center Functional Genomics, Ernst-Moritz-Arndt-University, Greifswald, Germany
| | - Achim G. Beule
- Department of Otorhinolaryngology, Head and Neck Surgery, Greifswald University Hospital, Greifswald, Germany; and
- Department of Otorhinolaryngology, University Hospital, Münster, Germany
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22
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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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23
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Eiffler I, Behnke J, Ziesemer S, Müller C, Hildebrandt JP. Staphylococcus aureus α-toxin-mediated cation entry depolarizes membrane potential and activates p38 MAP kinase in airway epithelial cells. Am J Physiol Lung Cell Mol Physiol 2016; 311:L676-85. [PMID: 27496896 DOI: 10.1152/ajplung.00090.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 07/29/2016] [Indexed: 11/22/2022] Open
Abstract
Membrane potential (Vm)-, Na(+)-, or Ca(2+)-sensitive fluorescent dyes were used to analyze changes in Vm or intracellular ion concentrations in airway epithelial cells treated with Staphylococcus aureus α-toxin (Hla), a major virulence factor of pathogenic strains of these bacteria. Gramicidin, a channel-forming peptide causing membrane permeability to monovalent cations, a mutated form of Hla, rHla-H35L, which forms oligomers in the plasma membranes of eukaryotic cells but fails to form functional transmembrane pores, or the cyclodextrin-derivative IB201, a blocker of the Hla pore, were used to investigate the permeability of the pore. Na(+) as well as Ca(2+) ions were able to pass the Hla pore and accumulated in the cytosol. The pore-mediated influx of calcium ions was blocked by IB201. Treatment of cells with recombinant Hla resulted in plasma membrane depolarization as well as in increases in the phosphorylation levels of paxillin (signaling pathway mediating disruption of the actin cytoskeleton) and p38 MAP kinase (signaling pathway resulting in defensive actions). p38 MAP kinase phosphorylation, but not paxillin phosphorylation, was elicited by treatment of cells with gramicidin. Although treatment of cells with rHla-H35L resulted in the formation of membrane-associated heptamers, none of these cellular effects were observed in our experiments. This indicates that formation of functional Hla-transmembrane pores is required to induce the cell physiological changes mediated by α-toxin. Specifically, the changes in ion equilibria and plasma membrane potential are important activators of p38 MAP kinase, a signal transduction module involved in host cell defense.
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Affiliation(s)
- Ina Eiffler
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Greifswald, Germany
| | - Jane Behnke
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Greifswald, Germany
| | - Sabine Ziesemer
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Greifswald, Germany
| | - Christian Müller
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Greifswald, Germany
| | - Jan-Peter Hildebrandt
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Greifswald, Germany
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Dissecting the role of ADAM10 as a mediator of Staphylococcus aureus α-toxin action. Biochem J 2016; 473:1929-40. [DOI: 10.1042/bcj20160062] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/28/2016] [Indexed: 01/26/2023]
Abstract
This work elucidates the role of the transmembrane protease ADAM10 (a disintegrin and metalloprotease 10) for the action of Staphylococcus aureus α-toxin, by showing that the cytotoxicity of α-toxin does not depend on ADAM10’s catalytic activity but on the chaperone function of its prodomain.
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25
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Stentzel S, Teufelberger A, Nordengrün M, Kolata J, Schmidt F, van Crombruggen K, Michalik S, Kumpfmüller J, Tischer S, Schweder T, Hecker M, Engelmann S, Völker U, Krysko O, Bachert C, Bröker BM. Staphylococcal serine protease-like proteins are pacemakers of allergic airway reactions to Staphylococcus aureus. J Allergy Clin Immunol 2016; 139:492-500.e8. [PMID: 27315768 DOI: 10.1016/j.jaci.2016.03.045] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Revised: 02/15/2016] [Accepted: 03/22/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND A substantial subgroup of asthmatic patients have "nonallergic" or idiopathic asthma, which often takes a severe course and is difficult to treat. The cause might be allergic reactions to the gram-positive pathogen Staphylococcus aureus, a frequent colonizer of the upper airways. However, the driving allergens of S aureus have remained elusive. OBJECTIVE We sought to search for potentially allergenic S aureus proteins and characterize the immune response directed against them. METHODS S aureus extracellular proteins targeted by human serum IgG4 were identified by means of immunoblotting to screen for potential bacterial allergens. Candidate antigens were expressed as recombinant proteins and used to analyze the established cellular and humoral immune responses in healthy adults and asthmatic patients. The ability to induce a type 2 immune response in vivo was tested in a mouse asthma model. RESULTS We identified staphylococcal serine protease-like proteins (Spls) as dominant IgG4-binding S aureus proteins. SplA through SplF are extracellular proteases of unknown function expressed by S aureus in vivo. Spls elicited IgE antibody responses in most asthmatic patients. In healthy S aureus carriers and noncarriers, peripheral blood T cells elaborated TH2 cytokines after stimulation with Spls, as is typical for allergens. In contrast, TH1/TH17 cytokines, which dominated the response to S aureus α-hemolysin, were of low concentration or absent. In mice inhalation of SplD without adjuvant induced lung inflammation characterized by TH2 cytokines and eosinophil infiltration. CONCLUSION We identify Spls as triggering allergens released by S aureus, opening prospects for diagnosis and causal therapy of asthma.
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Affiliation(s)
- Sebastian Stentzel
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | | | - Maria Nordengrün
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Julia Kolata
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany; Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Frank Schmidt
- Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany; Junior Group Applied Proteomics, ZIK FunGene, University Medicine Greifswald, Greifswald, Germany
| | | | - Stephan Michalik
- Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany; Junior Group Applied Proteomics, ZIK FunGene, University Medicine Greifswald, Greifswald, Germany
| | - Jana Kumpfmüller
- Department of Pharmaceutical Biotechnology, Institute of Pharmacy, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany; Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, HKI, Jena, Germany
| | - Sebastian Tischer
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Thomas Schweder
- Department of Pharmaceutical Biotechnology, Institute of Pharmacy, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany
| | - Michael Hecker
- Institute for Microbiology, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany
| | - Susanne Engelmann
- Institute for Microbiology, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany; Institute for Microbiology, University of Braunschweig, Braunschweig, Germany; Helmholtz Center for Infection Research, Microbial Proteomics, Braunschweig, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Olga Krysko
- Upper Airways Research Laboratory, Ghent University, Ghent, Belgium
| | - Claus Bachert
- Upper Airways Research Laboratory, Ghent University, Ghent, Belgium; Division of Ear, Nose, and Throat Diseases, Clintec, Karolinska Institute, Stockholm, Sweden
| | - Barbara M Bröker
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany.
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Panda S, Ding JL. Natural antibodies bridge innate and adaptive immunity. THE JOURNAL OF IMMUNOLOGY 2016; 194:13-20. [PMID: 25527792 DOI: 10.4049/jimmunol.1400844] [Citation(s) in RCA: 202] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Natural Abs, belonging to isotypes IgM, IgG3, and IgA, were discovered nearly half a century ago. Despite knowledge about the role of the polyreactive natural IgM in pathogen elimination, B cell survival and homeostasis, inflammatory diseases, and autoimmunity, there is a lack of clarity about the physiological role of natural IgG and natural IgA because they appear incapable of recognizing Ags on their own and are perceived as nonreactive. However, recent research revealed exciting functions of natural IgG in innate immunity. Natural IgG:lectin collaboration swiftly and effectively kills invading pathogens. These advances prompt further examination of natural Abs in immune defense and homeostasis, with the potential for developing novel therapeutics. This review provides new insights into the interaction between natural Abs and lectins, with implications on how interactions between molecules of the innate and adaptive immune systems bridge these two arms of immunity.
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Affiliation(s)
- Saswati Panda
- Department of Biological Sciences, National University of Singapore, Singapore 117543
| | - Jeak L Ding
- Department of Biological Sciences, National University of Singapore, Singapore 117543
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Vibrio vulnificus RtxA1 modulated calcium flux contributes reduced internalization in phagocytes. Life Sci 2015; 132:55-60. [PMID: 25916802 DOI: 10.1016/j.lfs.2015.03.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 03/05/2015] [Accepted: 03/25/2015] [Indexed: 12/17/2022]
Abstract
AIMS Vibrio vulnificusis an opportunistic pathogen that causes primary septicemia and wound infection with high mortality rate. This pathogen produces an RTX toxin (RtxA1) which can cause host cell rounding, cell death and interference with internalization by host phagocytes. However, the mechanism of RtxA1-induced phagocyte paralysis is not clear. MAIN METHODS Using the murine macrophage cell line RAW264.7, we measured cytotoxicity and phagocytosis of V. vulnificusin normal and calcium-depleted media. To deplete extracellular and cytosolic Ca(2+), cells were exposed to the calcium chelators ethylene glycol tetraacetic acid (EGTA) and 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, tetraacetoxymethyl esteris (BAPTA-AM), respectively. The cytotoxicity was examined by measuring the activity of lactate dehydrogenase (LDH) released from the damaged cells. The gentamicin protection assay was conducted to determine the number of internalized bacteria, while acridine orange staining was applied to visualize the intracellular bacteria. The fluorescent indicator fura-2-acetoxymethyl ester (fura 2-AM) was used to measure the Ca(2+)signal post-infection. KEY FINDINGS We revealed that extracellular Ca(2+)was essential for phagocytes to internalize V. vulnificus. Meanwhile, cytosolic Ca(2+)flux in RAW264.7 cells induced by an RtxA1 isogenic mutant was repressed by the parent strain. Furthermore, depletion of extracellular Ca(2+)level by EGTA significantly reduced the cytotoxicity but did not affect the antiphagocytic activity of RtxA1 toxin. SIGNIFICANCE Our results indicated that RtxA1 may interfere with cytosolic Ca(2+)flux of phagocyte to promote bacteria colonization.
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28
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Richter E, Harms M, Ventz K, Gierok P, Chilukoti RK, Hildebrandt JP, Mostertz J, Hochgräfe F. A multi-omics approach identifies key hubs associated with cell type-specific responses of airway epithelial cells to staphylococcal alpha-toxin. PLoS One 2015; 10:e0122089. [PMID: 25816343 PMCID: PMC4376684 DOI: 10.1371/journal.pone.0122089] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/17/2015] [Indexed: 12/18/2022] Open
Abstract
Responsiveness of cells to alpha-toxin (Hla) from Staphylococcus aureus appears to occur in a cell-type dependent manner. Here, we compare two human bronchial epithelial cell lines, i.e. Hla-susceptible 16HBE14o- and Hla-resistant S9 cells, by a quantitative multi-omics strategy for a better understanding of Hla-induced cellular programs. Phosphoproteomics revealed a substantial impact on phosphorylation-dependent signaling in both cell models and highlights alterations in signaling pathways associated with cell-cell and cell-matrix contacts as well as the actin cytoskeleton as key features of early rHla-induced effects. Along comparable changes in down-stream activity of major protein kinases significant differences between both models were found upon rHla-treatment including activation of the epidermal growth factor receptor EGFR and mitogen-activated protein kinases MAPK1/3 signaling in S9 and repression in 16HBE14o- cells. System-wide transcript and protein expression profiling indicate induction of an immediate early response in either model. In addition, EGFR and MAPK1/3-mediated changes in gene expression suggest cellular recovery and survival in S9 cells but cell death in 16HBE14o- cells. Strikingly, inhibition of the EGFR sensitized S9 cells to Hla indicating that the cellular capacity of activation of the EGFR is a major protective determinant against Hla-mediated cytotoxic effects.
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Affiliation(s)
- Erik Richter
- Competence Center Functional Genomics, Junior Research Group Pathoproteomics, University of Greifswald, 17489, Greifswald, Germany
| | - Manuela Harms
- Competence Center Functional Genomics, Junior Research Group Pathoproteomics, University of Greifswald, 17489, Greifswald, Germany
| | - Katharina Ventz
- Competence Center Functional Genomics, Junior Research Group Pathoproteomics, University of Greifswald, 17489, Greifswald, Germany
| | - Philipp Gierok
- Department of Biochemistry, University of Greifswald, 17487, Greifswald, Germany
| | - Ravi Kumar Chilukoti
- Interfaculty Institute for Genetics and Functional Genomics, Department of Functional Genomics, University of Greifswald, 17489, Greifswald, Germany
| | - Jan-Peter Hildebrandt
- Animal Physiology and Biochemistry, Zoological Institute, University of Greifswald, 17487, Greifswald, Germany
| | - Jörg Mostertz
- Competence Center Functional Genomics, Junior Research Group Pathoproteomics, University of Greifswald, 17489, Greifswald, Germany
| | - Falko Hochgräfe
- Competence Center Functional Genomics, Junior Research Group Pathoproteomics, University of Greifswald, 17489, Greifswald, Germany
- * E-mail:
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Hermann I, Räth S, Ziesemer S, Volksdorf T, Dress RJ, Gutjahr M, Müller C, Beule AG, Hildebrandt JP. Staphylococcus aureusHemolysin A Disrupts Cell–Matrix Adhesions in Human Airway Epithelial Cells. Am J Respir Cell Mol Biol 2015; 52:14-24. [DOI: 10.1165/rcmb.2014-0082oc] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Hildebrandt JP. Pore-forming virulence factors of Staphylococcus aureus destabilize epithelial barriers-effects of alpha-toxin in the early phases of airway infection. AIMS Microbiol 2015. [DOI: 10.3934/microbiol.2015.1.11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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31
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Asmat TM, Tenenbaum T, Jonsson AB, Schwerk C, Schroten H. Impact of calcium signaling during infection of Neisseria meningitidis to human brain microvascular endothelial cells. PLoS One 2014; 9:e114474. [PMID: 25464500 PMCID: PMC4252121 DOI: 10.1371/journal.pone.0114474] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 11/10/2014] [Indexed: 01/08/2023] Open
Abstract
The pili and outer membrane proteins of Neisseria meningitidis (meningococci) facilitate bacterial adhesion and invasion into host cells. In this context expression of meningococcal PilC1 protein has been reported to play a crucial role. Intracellular calcium mobilization has been implicated as an important signaling event during internalization of several bacterial pathogens. Here we employed time lapse calcium-imaging and demonstrated that PilC1 of meningococci triggered a significant increase in cytoplasmic calcium in human brain microvascular endothelial cells, whereas PilC1-deficient meningococci could not initiate this signaling process. The increase in cytosolic calcium in response to PilC1-expressing meningococci was due to efflux of calcium from host intracellular stores as demonstrated by using 2-APB, which inhibits the release of calcium from the endoplasmic reticulum. Moreover, pre-treatment of host cells with U73122 (phospholipase C inhibitor) abolished the cytosolic calcium increase caused by PilC1-expressing meningococci demonstrating that active phospholipase C (PLC) is required to induce calcium transients in host cells. Furthermore, the role of cytosolic calcium on meningococcal adherence and internalization was documented by gentamicin protection assay and double immunofluorescence (DIF) staining. Results indicated that chelation of intracellular calcium by using BAPTA-AM significantly impaired PilC1-mediated meningococcal adherence to and invasion into host endothelial cells. However, buffering of extracellular calcium by BAPTA or EGTA demonstrated no significant effect on meningococcal adherence to and invasion into host cells. Taken together, these results indicate that meningococci induce calcium release from intracellular stores of host endothelial cells via PilC1 and cytoplasmic calcium concentrations play a critical role during PilC1 mediated meningococcal adherence to and subsequent invasion into host endothelial cells.
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Affiliation(s)
- Tauseef M. Asmat
- Department of Pediatrics, Pediatric Infectious Diseases, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- * E-mail:
| | - Tobias Tenenbaum
- Department of Pediatrics, Pediatric Infectious Diseases, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Ann-Beth Jonsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Christian Schwerk
- Department of Pediatrics, Pediatric Infectious Diseases, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Horst Schroten
- Department of Pediatrics, Pediatric Infectious Diseases, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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Staphylococcal Esx proteins modulate apoptosis and release of intracellular Staphylococcus aureus during infection in epithelial cells. Infect Immun 2014; 82:4144-53. [PMID: 25047846 DOI: 10.1128/iai.01576-14] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The opportunistic pathogen Staphylococcus aureus is one of the major causes of health care-associated infections. S. aureus is primarily an extracellular pathogen, but it was recently reported to invade and replicate in several host cell types. The ability of S. aureus to persist within cells has been implicated in resistance to antimicrobials and recurrent infections. However, few staphylococcal proteins that mediate intracellular survival have been identified. Here we examine if EsxA and EsxB, substrates of the ESAT-6-like secretion system (Ess), are important during intracellular S. aureus infection. The Esx proteins are required for staphylococcal virulence, but their functions during infection are unclear. While isogenic S. aureus esxA and esxB mutants were not defective for epithelial cell invasion in vitro, a significant increase in early/late apoptosis was observed in esxA mutant-infected cells compared to wild-type-infected cells. Impeding secretion of EsxA by deleting C-terminal residues of the protein also resulted in a significant increase of epithelial cell apoptosis. Furthermore, cells transfected with esxA showed an increased protection from apoptotic cell death. A double mutant lacking both EsxA and EsxB also induced increased apoptosis but, remarkably, was unable to escape from cells as efficiently as the single mutants or the wild type. Thus, using in vitro models of intracellular staphylococcal infection, we demonstrate that EsxA interferes with host cell apoptotic pathways and, together with EsxB, mediates the release of S. aureus from the host cell.
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33
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Gierok P, Harms M, Richter E, Hildebrandt JP, Lalk M, Mostertz J, Hochgräfe F. Staphylococcus aureus alpha-toxin mediates general and cell type-specific changes in metabolite concentrations of immortalized human airway epithelial cells. PLoS One 2014; 9:e94818. [PMID: 24733556 PMCID: PMC3986243 DOI: 10.1371/journal.pone.0094818] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 03/20/2014] [Indexed: 11/23/2022] Open
Abstract
Staphylococcus aureus alpha-toxin (Hla) is a potent pore-forming cytotoxin that plays an important role in the pathogenesis of S. aureus infections, including pneumonia. The impact of Hla on the dynamics of the metabolome in eukaryotic host cells has not been investigated comprehensively. Using 1H-NMR, GC-MS and HPLC-MS, we quantified the concentrations of 51 intracellular metabolites and assessed alterations in the amount of 25 extracellular metabolites in the two human bronchial epithelial cell lines S9 and 16HBE14o− under standard culture conditions and after treatment with sub-lethal amounts (2 µg/ml) of recombinant Hla (rHla) in a time-dependent manner. Treatment of cells with rHla caused substantial decreases in the concentrations of intracellular metabolites from different metabolic pathways in both cell lines, including ATP and amino acids. Concomitant increases in the extracellular concentrations were detected for various intracellular compounds, including nucleotides, glutathione disulfide and NAD+. Our results indicate that rHla has a major impact on the metabolome of eukaryotic cells as a consequence of direct rHla-mediated alterations in plasma membrane permeability or indirect effects mediated by cellular signalling. However, cell-specific changes also were observed. Glucose consumption and lactate production rates suggest that the glycolytic activity of S9 cells, but not of 16HBE14o− cells, is increased in response to rHla. This could contribute to the observed higher level of resistance of S9 cells against rHla-induced membrane damage.
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Affiliation(s)
- Philipp Gierok
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Manuela Harms
- Competence Center Functional Genomics, Junior Research Group Pathoproteomics, University of Greifswald, Greifswald, Germany
| | - Erik Richter
- Competence Center Functional Genomics, Junior Research Group Pathoproteomics, University of Greifswald, Greifswald, Germany
| | - Jan-Peter Hildebrandt
- Animal Physiology and Biochemistry, Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
| | - Michael Lalk
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Jörg Mostertz
- Competence Center Functional Genomics, Junior Research Group Pathoproteomics, University of Greifswald, Greifswald, Germany
| | - Falko Hochgräfe
- Competence Center Functional Genomics, Junior Research Group Pathoproteomics, University of Greifswald, Greifswald, Germany
- * E-mail:
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Panda S, Zhang J, Yang L, Anand GS, Ding JL. Molecular interaction between natural IgG and ficolin--mechanistic insights on adaptive-innate immune crosstalk. Sci Rep 2014; 4:3675. [PMID: 24419227 PMCID: PMC3891018 DOI: 10.1038/srep03675] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 12/13/2013] [Indexed: 11/09/2022] Open
Abstract
Recently, we found that natural IgG (nIgG; a non-specific immunoglobulin of adaptive immunity) is not quiescent, but plays a crucial role in immediate immune defense by collaborating with ficolin (an innate immune protein). However, how the nIgG and ficolin interplay and what factors control the complex formation during infection is unknown. Here, we found that mild acidosis and hypocalcaemia induced by infection- inflammation condition increased the nIgG:ficolin complex formation. Hydrogen-deuterium exchange mass spectrometry delineated the binding interfaces to the CH2-CH3 region of nIgG Fc and P-subdomain of ficolin FBG domain. Infection condition exposes novel binding sites. Site-directed mutagenesis and surface plasmon resonance analyses of peptides, derived from nIgG and ficolin, defined the interacting residues between the proteins. These results provide mechanistic insights on the interaction between two molecules representing the adaptive and innate immune pathways, prompting potential development of immunomodulatory/prophylactic peptides tunable to prevailing infection conditions.
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Affiliation(s)
- Saswati Panda
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543
| | - Jing Zhang
- NUS graduate School for Integrative Science and Engineering, National University of Singapore, Singapore, 117543
- Current address: FIMS & BJRC, The 1 Affiliated Hospital and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China, 710061
| | - Lifeng Yang
- Computational and Systems Biology, Singapore-MIT Alliance, 4 Engineering Drive 3, Singapore, 117576
- Current address: School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637511
| | - Ganesh S. Anand
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543
| | - Jeak L. Ding
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543
- Computational and Systems Biology, Singapore-MIT Alliance, 4 Engineering Drive 3, Singapore, 117576
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Panda S, Zhang J, Tan NS, Ho B, Ding JL. Natural IgG antibodies provide innate protection against ficolin-opsonized bacteria. EMBO J 2013; 32:2905-19. [PMID: 24002211 PMCID: PMC3831310 DOI: 10.1038/emboj.2013.199] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 08/08/2013] [Indexed: 11/09/2022] Open
Abstract
For nearly five decades since its discovery, the role of natural IgG, which pre-exists in neonates and uninfected individuals, has remained unclear due to the general perception that natural antibodies lack affinity for pathogens. Here, we show for the first time that natural IgG recognizes a spectrum of bacteria through lectins like ficolin and mannose binding lectin (MBL). Infection-inflammation condition markedly increased the affinity of natural IgG for bacteria associated with ficolins. After opsonization with IgG:ficolin complex, the bacteria were phagocytosed by monocytes via FcγRI. Infection of C3(-/-) mice indicated that the natural IgG-mediated immune complex was formed independently of C3. AID(-/-) mice lacking IgG were susceptible to infection, unless reconstituted with natural IgG. Thus, we have proven that natural IgG is not quiescent; rather, it plays a vital and immediate role in immune defense. Our findings provide a fresh perspective on natural antibodies, opening new avenues to explore host-microbe interaction.
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Affiliation(s)
- Saswati Panda
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Jing Zhang
- NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Nguan Soon Tan
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Institute of Molecular and Cell Biology, Proteos, Singapore
| | - Bow Ho
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jeak Ling Ding
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
- Singapore MIT Alliance, National University of Singapore, Singapore, Singapore
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Guo H, Wielsch N, Hafke JB, Svatoš A, Mithöfer A, Boland W. A porin-like protein from oral secretions of Spodoptera littoralis larvae induces defense-related early events in plant leaves. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:849-58. [PMID: 23845235 DOI: 10.1016/j.ibmb.2013.06.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 06/11/2013] [Accepted: 06/14/2013] [Indexed: 05/08/2023]
Abstract
Insect herbivory on plants is a complex incident consisting of at least two different aspects, namely mechanical damage and chemical challenge, as feeding insects introduce oral secretions (OS) into the wounded tissue of the attacked plant. Mechanical wounding alone is sufficient to induce a set of defense-related reactions in host plants, but some early events such as membrane potential (Vm) changes and cytosolic Ca²⁺-elevations can be triggered only by herbivores suggesting that OS-derived molecules are involved in those processes. Following an assay-guided purification based on planar lipid bilayer membrane technique in combination with proteomic analysis, a porin-like protein (PLP) of most likely bacterial origin was determined from collected OS of Spodoptera littoralis larvae. PLP exhibited channel-forming activity. Further, early defense-related events in plant-insect interaction were evaluated by using a purified fraction and α-hemolysin (α-HL) as a commercial pore-forming compound. Both up-regulated the calmodulin-like CML42 in Arabidopsis thaliana, which only responds to oral secretion and not to wounding. An elevation of in vivo [Ca²⁺](cyt) was not observed. Because membrane channel formation is a widespread phenomenon in plant-insect interactions, this PLP might represent an example for microbial compounds from the insect gut which are initially involved in plant-insect interactions.
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Affiliation(s)
- Huijuan Guo
- Bioorganic Chemistry Department, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, D-07745 Jena, Germany
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Parimon T, Li Z, Bolz DD, McIndoo ER, Bayer CR, Stevens DL, Bryant AE. Staphylococcus aureus α-hemolysin promotes platelet-neutrophil aggregate formation. J Infect Dis 2013; 208:761-70. [PMID: 23698812 DOI: 10.1093/infdis/jit235] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) causes severe hemorrhagic necrotizing pneumonia associated with high mortality. Exotoxins have been implicated in the pathogenesis of this infection; however, the cellular mechanisms responsible remain largely undefined. Because platelet-neutrophil aggregates (PNAs) can dysregulate inflammatory responses and contribute to tissue destruction, we investigated whether exotoxins from MRSA could stimulate formation of PNAs in human whole blood. Strong PNA formation was stimulated by toxins from stationary phase but not log phase CA-MRSA, and α-hemolysin was singularly identified as the mediator of this activity. MRSA exotoxins also caused neutrophil (polymorphonuclear leukocyte) activation, as measured by increased CD11b expression, although platelet binding was not driven by this mechanism; rather, α-hemolysin-induced PNA formation was solely platelet P-selectin dependent. These findings suggest a role for S. aureus α-hemolysin-induced PNA formation in alveolar capillary destruction in hemorrhagic/necrotizing pneumonia caused by CA-MRSA and offer novel targets for intervention.
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Affiliation(s)
- Tanyalak Parimon
- Research and Development Service, Infectious Diseases Section, Veterans Affairs Medical Center, Boise, Idaho 83702, USA. (
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Räth S, Ziesemer S, Witte A, Konkel A, Müller C, Hildebrandt P, Völker U, Hildebrandt JP. S. aureus haemolysin A-induced IL-8 and IL-6 release from human airway epithelial cells is mediated by activation of p38- and Erk-MAP kinases and additional, cell type-specific signalling mechanisms. Cell Microbiol 2013; 15:1253-65. [PMID: 23347173 DOI: 10.1111/cmi.12113] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 01/11/2013] [Accepted: 01/14/2013] [Indexed: 01/25/2023]
Abstract
Soluble virulence-associated factors of Staphylococcus aureus like haemolysin A (Hla) induce secretion of chemo/cytokines from airway epithelial cells. To elucidate the potential roles of specific signalling pathways in this response, we treated 16HBE14o-, S9 or A549 cells with recombinant Hla (rHla). In a dose-dependent manner, rHla induced secretion of IL-8 in all three cell types, but IL-6 release only in 16HBE14o- and S9 cells. rHla-mediated secretion of IL-8 and IL-6 was suppressed by pre-incubation of cells with inhibitors of Erk type or p38 MAP kinases, indicating that activation of these signalling pathways is essential for IL-8 release in all three cell types and for IL-6 release in 16HBE14o- and S9 cells. The rHla-mediated phosphorylation and activation of p38 MAP kinase seem to depend on elevations in [Ca(2+)]i, an early response in rHla-treated cells. Inhibitors of calmodulin or calcium/calmodulin-dependent kinase II attenuated rHla-mediated release of IL-8 in 16HBE14o- and A549 cells and of IL-6 in 16HBE14o- cells. This indicates that rHla may mediate simultaneous activation of calmodulin-dependent processes as additional prerequisites for chemo/cytokine secretion.However, the inhibitors of calmodulin-dependent signalling did not affect rHla-induced p38 MAP kinase phosphorylation, indicating that this pathway works in parallel with p38 MAP kinase.
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Affiliation(s)
- Susann Räth
- Animal Physiology and Biochemistry, Zoological Institute, Ernst Moritz Arndt University, Johann Sebastian Bach-Strasse 11/12, D-17487 Greifswald, Germany
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The Staphylococcus aureus alpha-toxin perturbs the barrier function in Caco-2 epithelial cell monolayers by altering junctional integrity. Infect Immun 2012; 80:1670-80. [PMID: 22354024 DOI: 10.1128/iai.00001-12] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Increased microvascular permeability is a hallmark of sepsis and septic shock. Intestinal mucosal dysfunction may allow translocation of bacteria and their products, thereby promoting sepsis and inflammation. Although Staphylococcus aureus alpha-toxin significantly contributes to sepsis and perturbs the endothelial barrier function, little is known about possible effects of S. aureus alpha-toxin on human epithelial barrier functions. We hypothesize that S. aureus alpha-toxin in the blood can impair the intestinal epithelial barrier and thereby facilitate the translocation of luminal bacteria into the blood, which may in turn aggravate a septic condition. Here, we showed that staphylococcal alpha-toxin disrupts the barrier integrity of human intestinal epithelial Caco-2 cells as evidenced by decreased transepithelial electrical resistance (TER) and reduced cellular levels of junctional proteins, such as ZO-1, ZO-3, and E-cadherin. The Caco-2 cells also responded to alpha-toxin with an elevated cytosolic calcium ion concentration ([Ca(2+)](i)), elicited primarily by calcium influx from the extracellular environment, as well as with a significant reduction in TER, which was modulated by intracellular calcium chelation. Moreover, a significantly larger reduction in TER and amounts of the junctional proteins, viz., ZO-3 and occludin, was achieved by basolateral than by apical application of the alpha-toxin. These experimental findings thus support the hypothesis that free staphylococcal alpha-toxin in the bloodstream may cause intestinal epithelial barrier dysfunction and further aggravate the septic condition by promoting the release of intestinal bacteria into the underlying tissues and the blood.
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Shen JC, Cope E, Chen B, Leid JG, Cohen NA. Regulation of murine sinonasal cilia function by microbial secreted factors. Int Forum Allergy Rhinol 2012; 2:104-10. [PMID: 22253045 DOI: 10.1002/alr.21002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 10/26/2011] [Accepted: 11/01/2011] [Indexed: 11/06/2022]
Abstract
BACKGROUND Chronic rhinosinusitis is a multifactorial disease resulting in impaired mucociliary clearance. Recent literature suggests that different bacterial species are associated with varied disease severity. We examined the immediate effect of microbial secreted factors on sinonasal ciliary function. METHODS Murine primary sinonasal cultures were established in an air-liquid interface (ALI). Bacterial supernatants were isolated from H. influenza, S. pneumoniae, S. aureus, and P. aeruginosa cultures, as well as co-cultures of H. influenza/S. pneumoniae and S. aureus/P. aeruginosa. Controlling for pH and osmolarity, supernatants were administered at 50% concentration to the apical surface of the ALI culture. Basal ciliary beat frequency (CBF) was recorded for 20 minutes, at 5-minute intervals. Control groups were treated with culture broth. At minimum, experiments were performed in triplicate. Stimulated CBF was recorded after mechanical stimulation via short bursts of pressurized air (55 mmHg). RESULTS All supernatants reduced basal CBF. S. pneumoniae and P. aeruginosa caused significant reduction in CBF at all time points, with the largest decrease of -46.3 ± 1.6% (p < 0.001) for S. pneumoniae and -27.1 ± 2.8% (p < 0.001) for P. aeruginosa. S. aureus caused the basal CBF to decline by -33.0 ± 2.8% (p < 0.001) at 5 minutes, which reversed by 20 minutes. Overall, H. influenza yielded the least change in CBF (-20.0 ± 2.8%, p < 0.002). Co-cultures (H. influenza/S. pneumoniae and S. aureus/P. aeruginosa) resulted in delayed CBF reduction compared with monocultures. P. aeruginosa also blunted stimulated CBF (p < 0.02). CONCLUSION Results demonstrated acute decreases in murine sinonasal CBF after exposure to bacterial supernatants. Moreover, P. aeruginosa resulted in diminished ciliary stimulation capacity.
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Affiliation(s)
- Jessica C Shen
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Philadelphia, PA, USA
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Eisele NA, Anderson DM. Host Defense and the Airway Epithelium: Frontline Responses That Protect against Bacterial Invasion and Pneumonia. J Pathog 2011; 2011:249802. [PMID: 22567325 PMCID: PMC3335569 DOI: 10.4061/2011/249802] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Revised: 07/18/2011] [Accepted: 07/21/2011] [Indexed: 01/31/2023] Open
Abstract
Airway epithelial cells are the first line of defense against invading microbes, and they protect themselves through the production of carbohydrate and protein matrices concentrated with antimicrobial products. In addition, they act as sentinels, expressing pattern recognition receptors that become activated upon sensing bacterial products and stimulate downstream recruitment and activation of immune cells which clear invading microbes. Bacterial pathogens that successfully colonize the lungs must resist these mechanisms or inhibit their production, penetrate the epithelial barrier, and be prepared to resist a barrage of inflammation. Despite the enormous task at hand, relatively few virulence factors coordinate the battle with the epithelium while simultaneously providing resistance to inflammatory cells and causing injury to the lung. Here we review mechanisms whereby airway epithelial cells recognize pathogens and activate a program of antibacterial pathways to prevent colonization of the lung, along with a few examples of how bacteria disrupt these responses to cause pneumonia.
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Affiliation(s)
- Nicholas A. Eisele
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO 65211, USA
- The Laboratory for Infectious Disease Research, University of Missouri, Columbia, MO 65211, USA
| | - Deborah M. Anderson
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
- The Laboratory for Infectious Disease Research, University of Missouri, Columbia, MO 65211, USA
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Asmat TM, Agarwal V, Räth S, Hildebrandt JP, Hammerschmidt S. Streptococcus pneumoniae infection of host epithelial cells via polymeric immunoglobulin receptor transiently induces calcium release from intracellular stores. J Biol Chem 2011; 286:17861-9. [PMID: 21454571 DOI: 10.1074/jbc.m110.212225] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The pneumococcal surface protein C (PspC) is a major adhesin of Streptococcus pneumoniae (pneumococci) that interacts in a human-specific manner with the ectodomain of the human polymeric immunoglobulin receptor (pIgR) produced by respiratory epithelial cells. This interaction promotes bacterial colonization and bacterial internalization by initiating host signal transduction cascades. Here, we examined alterations of intracellular calcium ([Ca(2+)](i)) levels in epithelial cells during host cell infections with pneumococci via the PspC-hpIgR mechanism. The release of [Ca(2+)](i) from intracellular stores in host cells was significantly increased by wild-type pneumococci but not by PspC-deficient pneumococci. The increase in [Ca(2+)](i) was dependent on phospholipase C as pretreatment of cells with a phospholipase C-specific inhibitor U73122 abolished the increase in [Ca(2+)](i). In addition, we demonstrated the effect of [Ca(2+)](i) on pneumococcal internalization by epithelial cells. Uptake of pneumococci was significantly increased after pretreatment of epithelial cells with the cell-permeable calcium chelator 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid-tetraacetoxymethyl ester or use of EGTA as an extracellular Ca(2+)-chelating agent. In contrast, thapsigargin, an inhibitor of endoplasmic reticulum Ca(2+)ATPase, which increases [Ca(2+)](i) in a sustained fashion, significantly reduced pIgR-mediated pneumococcal invasion. Importantly, pneumococcal adherence to pIgR-expressing cells was not altered in the presence of inhibitors as demonstrated by immunofluorescence microscopy. In conclusion, these results demonstrate that pneumococcal infections induce mobilization of [Ca(2+)](i) from intracellular stores. This may constitute a defense response of host cells as the experimental reduction of intracellular calcium levels facilitates pneumococcal internalization by pIgR-expressing cells, whereas elevated calcium levels diminished bacterial internalization by host epithelial cells.
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Affiliation(s)
- Tauseef M Asmat
- Department of Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt University of Greifswald, Friedrich-Ludwig-Jahn-Strasse 15a, D-17487 Greifswald, Germany
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Abstract
Pore-forming toxins (PFT) comprise a large, structurally heterogeneous group of bacterial protein toxins. Nucleated target cells mount complex responses which allow them to survive moderate membrane damage by PFT. Autophagy has recently been implicated in responses to various PFT, but how this process is triggered is not known, and the significance of the phenomenon is not understood. Here, we show that S. aureus α-toxin, Vibrio cholerae cytolysin, streptolysin O and E. coli haemolysin activate two pathways leading to autophagy. The first pathway is triggered via AMP-activated protein kinase (AMPK). AMPK is a major energy sensor which induces autophagy by inhibiting the target of rapamycin complex 1 (TORC1) in response to a drop of the cellular ATP/AMP-ratio, as is also observed in response to membrane perforation. The second pathway is activated by the conserved eIF2α-kinase GCN2, which causes global translational arrest and promotes autophagy in response to starvation. The latter could be accounted for by impaired amino acid transport into target cells. Notably, PKR, an eIF2α-kinase which has been implicated in autophagy induction during viral infection, was also activated upon membrane perforation, and evidence was obtained that phosphorylation of eIF2α is required for the accumulation of autophagosomes in α-toxin-treated cells. Treatment with 3-methyl-adenine inhibited autophagy and disrupted the ability of cells to recover from sublethal attack by S. aureus α-toxin. We propose that PFT induce pro-autophagic signals through membrane perforation–dependent nutrient and energy depletion, and that an important function of autophagy in this context is to maintain metabolic homoeostasis.
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Tubby S, Wilson M, Nair SP. Inactivation of staphylococcal virulence factors using a light-activated antimicrobial agent. BMC Microbiol 2009; 9:211. [PMID: 19804627 PMCID: PMC2762988 DOI: 10.1186/1471-2180-9-211] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 10/05/2009] [Indexed: 12/03/2022] Open
Abstract
Background One of the limitations of antibiotic therapy is that even after successful killing of the infecting microorganism, virulence factors may still be present and cause significant damage to the host. Light-activated antimicrobials show potential for the treatment of topical infections; therefore if these agents can also inactivate microbial virulence factors, this would represent an advantage over conventional antibiotic therapy. Staphylococcus aureus produces a wide range of virulence factors that contribute to its success as a pathogen by facilitating colonisation and destruction of host tissues. Results In this study, the ability of the light-activated antimicrobial agent methylene blue in combination with laser light of 665 nm to inactivate staphylococcal virulence factors was assessed. A number of proteinaceous virulence factors were exposed to laser light in the presence of methylene blue and their biological activities re-determined. The activities of V8 protease, α-haemolysin and sphingomyelinase were shown to be inhibited in a dose-dependent manner by exposure to laser light in the presence of methylene blue. Conclusion These results suggest that photodynamic therapy could reduce the harmful impact of preformed virulence factors on the host.
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Affiliation(s)
- Sarah Tubby
- Division of Microbial Diseases, UCL Eastman Dental Institute, UK.
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Debellis L, Diana A, Arcidiacono D, Fiorotto R, Portincasa P, Altomare DF, Spirlì C, de Bernard M. The Vibrio cholerae cytolysin promotes chloride secretion from intact human intestinal mucosa. PLoS One 2009; 4:e5074. [PMID: 19333391 PMCID: PMC2659442 DOI: 10.1371/journal.pone.0005074] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Accepted: 03/05/2009] [Indexed: 12/02/2022] Open
Abstract
Background The pathogenicity of the Vibrio cholerae strains belonging to serogroup O1 and O139 is due to the production of virulence factors such as cholera toxin (CT) and the toxin-coregulated pilus (TCP). The remaining serogroups, which mostly lack CT and TCP, are more frequently isolated from aquatic environmental sources than from clinical samples; nevertheless, these strains have been reported to cause human disease, such as sporadic outbreaks of watery diarrhoea and inflammatory enterocolitis. This evidence suggested the possibility that other virulence factor(s) than cholera toxin might be crucial in the pathogenesis of Vibrio cholerae-induced diarrhoea, but their nature remains unknown. VCC, the hemolysin produced by virtually all Vibrio cholerae strains, has been proposed as a possible candidate, though a clear-cut demonstration attesting VCC as crucial in the pathogenesis of Vibrio cholerae-induced diarrhoea is still lacking. Methodology/Principal Findings Electrophysiological parameters and paracellular permeability of stripped human healthy colon tissues, obtained at subtotal colectomy, mounted in Ussing chamber were studied in the presence or absence of VCC purified from culture supernatants of V. cholerae O1 El Tor strain. Short circuit current (ISC) and transepithelial resistance (RT) were measured by a computerized voltage clamp system. The exposure of sigmoid colon specimens to 1 nM VCC resulted in an increase of ISC by 20.7%, with respect to the basal values, while RT was reduced by 12.3%. Moreover, increase in ISC was abolished by bilateral Cl− reduction. Conclusion/Significance Our results demonstrate that VCC, by forming anion channels on the apical membrane of enterocytes, triggers an outward transcellular flux of chloride. Such an ion movement, associated with the outward movement of Na+ and water, might be responsible for the diarrhoea caused by the non-toxigenic strains of Vibrio cholerae.
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Affiliation(s)
- Lucantonio Debellis
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
| | - Anna Diana
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
| | | | - Romina Fiorotto
- Department of Internal Medicine, Section of Digestive Diseases, Yale University, New Haven, Connecticut, United States of America
| | - Piero Portincasa
- Clinica Medica “A. Murri”, Department of Internal and Public Medicine, University Medical School, Bari, Italy
| | - Donato Francesco Altomare
- Department of Emergency and Organ Transplantation, General Surgery and Liver Transplantation Units, University of Bari, Policlinico, Bari, Italy
| | - Carlo Spirlì
- Department of Internal Medicine, Section of Digestive Diseases, Yale University, New Haven, Connecticut, United States of America
| | - Marina de Bernard
- Venetian Institute of Molecular Medicine, Padua, Italy
- Department of Biology, University of Padua, Padua, Italy
- * E-mail:
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Below S, Konkel A, Zeeck C, Müller C, Kohler C, Engelmann S, Hildebrandt JP. Virulence factors of Staphylococcus aureus induce Erk-MAP kinase activation and c-Fos expression in S9 and 16HBE14o- human airway epithelial cells. Am J Physiol Lung Cell Mol Physiol 2008; 296:L470-9. [PMID: 19098123 DOI: 10.1152/ajplung.90498.2008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Part of the innate defense of bronchial epithelia against bacterial colonization is regulated secretion of salt, water, and mucus as well as defensins and cytokines involving MAP kinase activation and alterations in early gene expression. We tested two different types of immortalized human airway epithelial cells (S9, 16HBE14o-) for activation of Erk-type MAP kinases and for expression of c-Fos on treatment with Staphylococcus aureus culture supernatants from the stationary growth phase [optical density (OD)(540 nm) = 10] or with recombinant S. aureus hemolysins A and B (Hla, Hlb). OD10 supernatants activated Erk-type MAP kinases and c-Fos expression in a concentration-dependent manner. Hla induced Erk-type kinase phosphorylation in S9 but not in 16HBE14o- cells. Hlb induced Erk activation in either cell type. Basal and stimulated levels of Erk-type MAP kinase phosphorylation were sensitive to the Mek1 inhibitor PD-98059, indicating that the bacterial products activated the entire signaling cascade that coregulates IL-8 induction and secretion. While c-Fos expression was enhanced by OD10 supernatants, Hla, and Hlb in S9 cells, 16HBE14o- cells responded to OD10 supernatant and Hlb but not to Hla. In S9 cells, PD-98059 suppressed c-Fos upregulation by OD10 supernatant, Hla, or Hlb, indicating that c-Fos expression requires activation of Erk-type MAP kinases. In 16HBE14o- cells, however, c-Fos expression by OD10 supernatant was sensitive to PD-98059, while that induced by Hlb was not. This indicates that ingredients of OD10 supernatants other than Hla or Hlb are activating Erk-type MAP kinases in 16HBE14o- cells and that other intracellular signaling systems apart from Erk-type MAP kinases contribute to Hlb-mediated regulation of c-Fos. Thus interaction of bacterial factors with airway epithelial cells may be highly cell type specific.
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Affiliation(s)
- Sabine Below
- Animal Physiology and Biochemistry, Zoological Institute, Ernst Moritz Arndt University, Greifswald, Germany
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