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Wang X, Uppu DSSM, Dickey SW, Burgin DJ, Otto M, Lee JC. Staphylococcus aureus delta toxin modulates both extracellular membrane vesicle biogenesis and amyloid formation. mBio 2023; 14:e0174823. [PMID: 37795985 PMCID: PMC10653798 DOI: 10.1128/mbio.01748-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/15/2023] [Indexed: 10/06/2023] Open
Abstract
IMPORTANCE Extracellular membrane vesicles (MVs) produced by Staphylococcus aureus in planktonic cultures encapsulate a diverse cargo of bacterial proteins, nucleic acids, and glycopolymers that are protected from destruction by external factors. δ-toxin, a member of the phenol soluble modulin family, was shown to be critical for MV biogenesis. Amyloid fibrils co-purified with MVs generated by virulent, community-acquired S. aureus strains, and fibril formation was dependent on expression of the S. aureus δ-toxin gene (hld). Mass spectrometry data confirmed that the amyloid fibrils were comprised of δ-toxin. Although S. aureus MVs were produced in vivo in a localized murine infection model, amyloid fibrils were not observed in the in vivo setting. Our findings provide critical insights into staphylococcal factors involved in MV biogenesis and amyloid formation.
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Affiliation(s)
- Xiaogang Wang
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Divakara SSM Uppu
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Seth W. Dickey
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
- Department of Veterinary Medicine, Virginia-Maryland Regional College of Veterinary Medicine,University of Maryland, Bethesda, Maryland, USA
| | - Dylan J. Burgin
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Jean C. Lee
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Malviya J, Alameri AA, Al-Janabi SS, Fawzi OF, Azzawi AL, Obaid RF, Alsudani AA, Alkhayyat AS, Gupta J, Mustafa YF, Karampoor S, Mirzaei R. Metabolomic profiling of bacterial biofilm: trends, challenges, and an emerging antibiofilm target. World J Microbiol Biotechnol 2023; 39:212. [PMID: 37256458 DOI: 10.1007/s11274-023-03651-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 05/17/2023] [Indexed: 06/01/2023]
Abstract
Biofilm-related infections substantially contribute to bacterial illnesses, with estimates indicating that at least 80% of such diseases are linked to biofilms. Biofilms exhibit unique metabolic patterns that set them apart from their planktonic counterparts, resulting in significant metabolic reprogramming during biofilm formation. Differential glycolytic enzymes suggest that central metabolic processes are markedly different in biofilms and planktonic cells. The glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is highly expressed in Staphylococcus aureus biofilm progenitors, indicating that changes in glycolysis activity play a role in biofilm development. Notably, an important consideration is a correlation between elevated cyclic di-guanylate monophosphate (c-di-GMP) activity and biofilm formation in various bacteria. C-di-GMP plays a critical role in maintaining the persistence of Pseudomonas aeruginosa biofilms by regulating alginate production, a significant biofilm matrix component. Furthermore, it has been demonstrated that S. aureus biofilm development is initiated by several tricarboxylic acid (TCA) intermediates in a FnbA-dependent manner. Finally, Glucose 6-phosphatase (G6P) boosts the phosphorylation of histidine-containing protein (HPr) by increasing the activity of HPr kinase, enhancing its interaction with CcpA, and resulting in biofilm development through polysaccharide intercellular adhesion (PIA) accumulation and icaADBC transcription. Therefore, studying the metabolic changes associated with biofilm development is crucial for understanding the complex mechanisms involved in biofilm formation and identifying potential targets for intervention. Accordingly, this review aims to provide a comprehensive overview of recent advances in metabolomic profiling of biofilms, including emerging trends, prevailing challenges, and the identification of potential targets for anti-biofilm strategies.
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Affiliation(s)
- Jitendra Malviya
- Department of Life Sciences and Biological Sciences, IES University, Bhopal, India
| | - Ameer A Alameri
- Department of Chemistry, College of Science, University of Babylon, Babylon, Iraq
| | - Saif S Al-Janabi
- Medical Laboratory Techniques Department, Al-Maarif University College, Ramadi, Iraq
| | | | | | - Rasha Fadhel Obaid
- Department of Biomedical Engineering, Al-Mustaqbal University College, Babylon, Iraq
| | - Ali A Alsudani
- College of Science, University of Al-Qadisiyah, Al-Diwaniyah, Iraq
| | - Ameer S Alkhayyat
- Medical Laboratory Technology Department, College of Medical Technology, The Islamic University, Najaf, Iraq
| | - Jitendra Gupta
- Institute of Pharmaceutical Research, GLA University, Mathura, 281406, U. P., India
| | - Yasser Fakri Mustafa
- Department of Pharmaceutical Chemistry, College of Pharmacy, University of Mosul, Mosul, 41001, Iraq
| | - Sajad Karampoor
- Gastrointestinal and Liver Diseases Research Center, Iran University of Medical Sciences, Tehran, Iran.
| | - Rasoul Mirzaei
- Venom and Biotherapeutics Molecules Lab, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
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3
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Wang X, Uppu DS, Dickey SW, Burgin DJ, Otto M, Lee JC. Staphylococcus aureus Delta Toxin Modulates both Extracellular Membrane Vesicle Biogenesis and Amyloid Formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.23.533957. [PMID: 36993475 PMCID: PMC10055364 DOI: 10.1101/2023.03.23.533957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Staphylococcus aureus secretes phenol-soluble modulins (PSMs), a family of small, amphipathic, secreted peptides with multiple biologic activities. Community-acquired S. aureus strains produce high levels of PSMs in planktonic cultures, and PSM alpha peptides have been shown to augment the release of extracellular membrane vesicles (MVs). We observed that amyloids, aggregates of proteins characterized by a fibrillar morphology and stained with specific dyes, co-purified with MVs harvested from cell-free culture supernatants of community-acquired S. aureus strains. δ-toxin was a major component of amyloid fibrils that co-purified with strain LAC MVs, and δ-toxin promoted the production of MVs and amyloid fibrils in a dose-dependent manner. To determine whether MVs and amyloid fibrils were generated under in vivo conditions, we inoculated mice with S. aureus harvested from planktonic cultures. Bacterial MVs could be isolated and purified from lavage fluids recovered from infected animals. Although δ-toxin was the most abundant PSM in lavage fluids, amyloid fibrils could not be detected in these samples. Our findings expand our understanding of amyloid fibril formation in S. aureus cultures, reveal important roles of δ-toxin in amyloid fibril formation and MV biogenesis, and demonstrate that MVs are generated in vivo in a staphylococcal infection model. Importance Extracellular membrane vesicles (MVs) produced by Staphylococcus aureus in planktonic cultures encapsulate a diverse cargo of bacterial proteins, nucleic acids, and glycopolymers that are protected from destruction by external factors. δ-toxin, a member of the phenol soluble modulin family, was shown to be critical for MV biogenesis. Amyloid fibrils co-purified with MVs generated by virulent, community-acquired S. aureus strains, and fibril formation was dependent on expression of the S. aureus δ-toxin gene ( hld ). Mass spectrometry data confirmed that the amyloid fibrils were comprised of δ-toxin. Although S. aureus MVs were produced in vivo in a localized murine infection model, amyloid fibrils were not observed in the in vivo setting. Our findings provide critical insights into staphylococcal factors involved in MV biogenesis and amyloid formation.
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4
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Sabino YNV, Cotter PD, Mantovani HC. Anti-virulence compounds against Staphylococcus aureus associated with bovine mastitis: A new therapeutic option? Microbiol Res 2023; 271:127345. [PMID: 36889204 DOI: 10.1016/j.micres.2023.127345] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 02/22/2023] [Accepted: 02/26/2023] [Indexed: 03/05/2023]
Abstract
Bovine mastitis represents a major economic burden faced by the dairy industry. S. aureus is an important and prevalent bovine mastitis-associated pathogen in dairy farms worldwide. The pathogenicity and persistence of S. aureus in the bovine mammary gland are associated with the expression of a range of virulence factors involved in biofilm formation and the production of several toxins. The traditional therapeutic approach to treating bovine mastitis includes the use of antibiotics, but the emergence of antibiotic-resistant strains has caused therapeutic failure. New therapeutic approaches targeting virulence factors of S. aureus rather than cell viability can have several advantages including lower selective pressure towards the development of resistance and little impact on the host commensal microbiota. This review summarizes the potential of anti-virulence therapies to control S. aureus associated with bovine mastitis focusing on anti-toxin, anti-biofilm, and anti-quorum sensing compounds. It also points to potential sources of new anti-virulence inhibitors and presents screening strategies for identifying these compounds.
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Affiliation(s)
| | | | - Hilario C Mantovani
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, USA.
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5
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Mashayamombe M, Carda-Diéguez M, Mira A, Fitridge R, Zilm PS, Kidd SP. Subpopulations in Strains of Staphylococcus aureus Provide Antibiotic Tolerance. Antibiotics (Basel) 2023; 12:antibiotics12020406. [PMID: 36830316 PMCID: PMC9952555 DOI: 10.3390/antibiotics12020406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/12/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
The ability of Staphylococcus aureus to colonise different niches across the human body is linked to an adaptable metabolic capability, as well as its ability to persist within specific tissues despite adverse conditions. In many cases, as S. aureus proliferates within an anatomical niche, there is an associated pathology. The immune response, together with medical interventions such as antibiotics, often removes the S. aureus cells that are causing this disease. However, a common issue in S. aureus infections is a relapse of disease. Within infected tissue, S. aureus exists as a population of cells, and it adopts a diversity of cell types. In evolutionary biology, the concept of "bet-hedging" has established that even in positive conditions, there are members that arise within a population that would be present as non-beneficial, but if those conditions change, these traits could allow survival. For S. aureus, some of these cells within an infection have a reduced fitness, are not rapidly proliferating or are the cause of an active host response and disease, but these do remain even after the disease seems to have been cleared. This is true for persistence against immune responses but also as a continual presence in spite of antibiotic treatment. We propose that the constant arousal of suboptimal populations at any timepoint is a key strategy for S. aureus long-term infection and survival. Thus, understanding the molecular basis for this feature could be instrumental to combat persistent infections.
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Affiliation(s)
- Matipaishe Mashayamombe
- Department of Vascular Surgery, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
- Discipline of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5000, Australia
- Basil Hetzel Institute for Translational Research, The Queen Elizabeth Hospital, Adelaide, SA 5000, Australia
| | - Miguel Carda-Diéguez
- Department of Health and Genomics, Center for Advanced Research in Public Health, FISABIO Institute, 46020 Valencia, Spain
| | - Alex Mira
- Department of Health and Genomics, Center for Advanced Research in Public Health, FISABIO Institute, 46020 Valencia, Spain
- School of Health and Welfare, Jönköping University, 551 11 Jönköping, Sweden
| | - Robert Fitridge
- Department of Vascular Surgery, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
- Discipline of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5000, Australia
- Basil Hetzel Institute for Translational Research, The Queen Elizabeth Hospital, Adelaide, SA 5000, Australia
| | - Peter S. Zilm
- Adelaide Dental School, The University of Adelaide, Adelaide, SA 5000, Australia
| | - Stephen P. Kidd
- Department of Molecular and Biomedical Sciences, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
- Research Centre for Infectious Disease, The University of Adelaide, Adelaide, SA 5005, Australia
- Australian Centre for Antimicrobial Resistance Ecology (ACARE), The University of Adelaide, Adelaide, SA 5005, Australia
- Correspondence:
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6
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Francis D, Bhairaddy A, Joy A, Hari GV, Francis A. Secretory proteins in the orchestration of microbial virulence: The curious case of Staphylococcus aureus. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 133:271-350. [PMID: 36707204 DOI: 10.1016/bs.apcsb.2022.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Microbial virulence showcases an excellent model for adaptive changes that enable an organism to survive and proliferate in a hostile environment and exploit host resources to its own benefit. In Staphylococcus aureus, an opportunistic pathogen of the human host, known for the diversity of the disease conditions it inflicts and the rapid evolution of antibiotic resistance, virulence is a consequence of having a highly plastic genome that is amenable to quick reprogramming and the ability to express a diverse arsenal of virulence factors. Virulence factors that are secreted to the host milieu effectively manipulate the host conditions to favor bacterial survival and growth. They assist in colonization, nutrient acquisition, immune evasion, and systemic spread. The structural and functional characteristics of the secreted virulence proteins have been shaped to assist S. aureus in thriving and disseminating effectively within the host environment and exploiting the host resources to its best benefit. With the aim of highlighting the importance of secreted virulence proteins in bacterial virulence, the present chapter provides a comprehensive account of the role of the major secreted proteins of S. aureus in orchestrating its virulence in the human host.
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Affiliation(s)
- Dileep Francis
- Department of Life Sciences, Kristu Jayanti College, Autonomous, Bengaluru, Karnataka, India.
| | - Anusha Bhairaddy
- Department of Life Sciences, Kristu Jayanti College, Autonomous, Bengaluru, Karnataka, India
| | - Atheene Joy
- Department of Life Sciences, Kristu Jayanti College, Autonomous, Bengaluru, Karnataka, India
| | | | - Ashik Francis
- Rajiv Gandhi Centre for Biotechnology, Trivandrum, Kerala, India
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7
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Polaske TJ, Gahan CG, Nyffeler KE, Lynn DM, Blackwell HE. Identification of small molecules that strongly inhibit bacterial quorum sensing using a high-throughput lipid vesicle lysis assay. Cell Chem Biol 2021; 29:605-614.e4. [PMID: 34932995 PMCID: PMC9035047 DOI: 10.1016/j.chembiol.2021.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/27/2021] [Accepted: 11/29/2021] [Indexed: 01/15/2023]
Abstract
Strategies to both monitor and block bacterial quorum sensing (QS), and thus associated infections, are of significant interest. We developed a straightforward assay to monitor biosurfactants and lytic agents produced by bacteria under the control of QS. The method is based on the lysis of synthetic lipid vesicles containing the environmentally sensitive fluorescent dye calcein. This assay allows for the in situ screening of compounds capable of altering biosurfactant production by bacteria, and thereby the identification of molecules that could potentially modulate QS pathways, and avoids the constraints of many of the cell-based assays in use today. Application of this assay in a high-throughput format revealed five molecules capable of blocking vesicle lysis by S. aureus. Two of these compounds were found to almost completely inhibit agr-based QS in S. aureus and represent the most potent small-molecule-derived QS inhibitors reported in this formidable pathogen.
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Affiliation(s)
- Thomas J Polaske
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA
| | - Curran G Gahan
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, WI 53706, USA
| | - Kayleigh E Nyffeler
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA; Microbiology Doctoral Training Program, University of Wisconsin-Madison, 1550 Linden Dr., Madison, WI 53706, USA
| | - David M Lynn
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA; Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, WI 53706, USA.
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA.
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8
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The Vancomycin Resistance-Associated Regulatory System VraSR Modulates Biofilm Formation of Staphylococcus epidermidis in an ica-Dependent Manner. mSphere 2021; 6:e0064121. [PMID: 34550006 PMCID: PMC8550092 DOI: 10.1128/msphere.00641-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The two-component system VraSR responds to the cell wall-active antibiotic stress in Staphylococcus epidermidis. To study its regulatory function in biofilm formation, a vraSR deletion mutant (ΔvraSR) was constructed using S. epidermidis strain 1457 (SE1457) as the parent strain. Compared to SE1457, the ΔvraSR mutant showed impaired biofilm formation both in vitro and in vivo with a higher ratio of dead cells within the biofilm. Consistently, the ΔvraSR mutant produced much less polysaccharide intercellular adhesin (PIA). The ΔvraSR mutant also showed increased susceptibility to the cell wall inhibitor and SDS, and its cell wall observed under a transmission electron microscope (TEM) appeared to be thinner and interrupted, which is in accordance with higher susceptibility to the stress. Complementation of vraSR in the ΔvraSR mutant restored the biofilm formation and the cell wall thickness to wild-type levels. Transcriptome sequencing (RNA-Seq) showed that the vraSR deletion affected the transcription levels of 73 genes, including genes involved in biofilm formation, bacterial programmed cell death (CidA-LrgAB system), glycolysis/gluconeogenesis, the pentose phosphate pathway (PPP), and the tricarboxylic acid (TCA) cycle, etc. The results of RNA-Seq were confirmed by quantitative real-time reverse transcription-PCR (qRT-PCR). In the ΔvraSR mutant, the expression of icaA and lrgAB was downregulated and the expression of icaR and cidA was upregulated, in comparison to that of SE1457. The transcriptional levels of antibiotic-resistant genes (pbp2, serp1412, murAA, etc.) had no significant changes. An electrophoretic mobility shift assay further revealed that phosphorylated VraR bound to the promoter regions of the ica operon, as well as its own promoter region. This study demonstrates that in S. epidermidis, VraSR is an autoregulator and directly regulates biofilm formation in an ica-dependent manner. Upon cell wall stress, it indirectly regulates cell death and drug resistance in association with alterations to multiple metabolism pathways. IMPORTANCES. epidermidis is a leading cause of hospital-acquired catheter-related infections, and its pathogenicity depends mostly on its ability to form biofilms on implants. The biofilm formation is a complex procedure that involves multiple regulating factors. Here, we show that a vancomycin resistance-associated two-component regulatory system, VraSR, plays an important role in modulating S. epidermidis biofilm formation and tolerance to stress. We demonstrate that S. epidermidis VraSR is an autoregulated system that selectively responds to stress targeting cell wall synthesis. Besides, phosphorylated VraR can bind to the promoter region of the ica operon and directly regulates polysaccharide intercellular adhesin production and biofilm formation in S. epidermidis. Furthermore, VraSR may indirectly modulate bacterial cell death and extracellular DNA (eDNA) release in biofilms through the CidA-LrgAB system. This work provides a new molecular insight into the mechanisms of VraSR-mediated modulation of the biofilm formation and cell death of S. epidermidis.
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9
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Damour A, Robin B, Deroche L, Broutin L, Bellin N, Verdon J, Lina G, Leclère FM, Garcia M, Cremniter J, Lévêque N, Bodet C. Phenol-soluble modulins α are major virulence factors of Staphylococcus aureus secretome promoting inflammatory response in human epidermis. Virulence 2021; 12:2474-2492. [PMID: 34516337 PMCID: PMC8451463 DOI: 10.1080/21505594.2021.1975909] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Staphylococcus aureus is a skin commensal microorganism commonly colonizing healthy humans. Nevertheless, S. aureus can also be responsible for cutaneous infections and contribute to flare-up of inflammatory skin diseases such as atopic dermatitis (AD), which is characterized by dysbiosis of the skin microbiota with S. aureus as the predominant species. However, the role of major virulence factors of this pathogen such as phenol-soluble modulin (PSM) toxins in epidermal inflammation remains poorly understood. Stimulation of primary human keratinocytes with sublytic concentrations of synthetic and purified PSM α3 resulted in upregulation of a large panel of pro-inflammatory chemokine and cytokine gene expression, including CXCL1, CXCL2, CXCL3, CXCL5, CXCL8, CCL20, IL-1α, IL-1β, IL-6, IL-36γ and TNF-α, while inducing the release of CXCL8, CCL20, TNF-α and IL-6. In addition, using S. aureus culture supernatant from mutants deleted from genes encoding either α-type PSMs or all PSM production, PSMs were shown to be the main factors of S. aureus secretome responsible for pro-inflammatory mediator induction in human keratinocytes. On the other hand, α-type PSM-containing supernatant triggered an intense induction of pro-inflammatory mediator expression and secretion during both topical and basal layer stimulation of an ex vivo model of human skin explants, a physiologically relevant model of pluristratified epidermis. Taken together, the results of this study show that PSMs and more specifically α-type PSMs are major virulence factors of S. aureus inducing a potent inflammatory response during infection of the human epidermis and could thereby contribute to AD flare-up through exacerbation of skin inflammation.
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Affiliation(s)
- Alexia Damour
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
| | - Brandon Robin
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
| | - Luc Deroche
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
| | - Lauranne Broutin
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France.,Laboratoire De Bactériologie, CHU de Poitiers, Poitiers, France
| | - Nicolas Bellin
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
| | - Julien Verdon
- Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université De Poitiers, Poitiers, France
| | - Gérard Lina
- CIRI Centre International de Recherche en Infectiologie, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, Lyon, France.,Centre National de Référence des Staphylocoques, Institut des Agent Infectieux, Hôpital de La Croix Rousse, Hospices Civils de Lyon, Lyon, France
| | - Franck Marie Leclère
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France.,Département de Chirurgie Plastique, Reconstructive et Esthétique, CHU de Poitiers, Poitiers, France
| | - Magali Garcia
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France.,Laboratoire de Virologie et Mycobactériologie, CHU de Poitiers, Poitiers, France
| | - Julie Cremniter
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France.,Laboratoire De Bactériologie, CHU de Poitiers, Poitiers, France
| | - Nicolas Lévêque
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France.,Laboratoire de Virologie et Mycobactériologie, CHU de Poitiers, Poitiers, France
| | - Charles Bodet
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
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10
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Zhou X, Zheng Y, Lv Q, Kong D, Ji B, Han X, Zhou D, Sun Z, Zhu L, Liu P, Jiang H, Jiang Y. Staphylococcus aureus N-terminus formylated δ-toxin tends to form amyloid fibrils, while the deformylated δ-toxin tends to form functional oligomer complexes. Virulence 2021; 12:1418-1437. [PMID: 34028320 PMCID: PMC8158037 DOI: 10.1080/21505594.2021.1928395] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The community-associated Methicillin-resistant Staphylococcus aureus strain (CA-MRSA) is highly virulent and has become a major focus of public health professionals. Phenol-soluble modulins (PSM) are key factors in its increased virulence. δ-Toxin belongs to PSM family and has copious secretion in many S. aureus strains. In addition, δ-toxin exists in the S. aureus culture supernatant as both N-terminus formylated δ-toxin (fδ-toxin) and deformylated δ-toxin (dfδ-toxin) groups. Although δ-toxin has been studied for more than 70 years, its functions remain unclear. We isolated and purified PSMs from the supernatant of S. aureus MW2, and found fibrils and oligomers aggregates by Size Exclusion Chromatography. After analyzing PSM aggregates and using peptide simulations, we found that the difference in the monomer structure of fδ-toxin and dfδ-toxin might ultimately lead to differences in the aggregation ability: fδ-toxin and dfδ-toxin tend to form fibrils and oligomers respectively. Of note, we found that fδ-toxin fibrils enhanced the stability of biofilms, while dfδ-toxin oligomers promoted their dispersal. Additionally, oligomeric dfδ-toxin combined with PSMα to form a complex with enhanced functionality. Due to the different aggregation capabilities and functions of fδ-toxin and dfδ-toxin, we speculate that they may be involved in the regulation of physiological activities of S. aureus. Moreover, the dfδ-toxin oligomer not only provides a new form of complex in the study of PSMα, but also has significance as a reference in oligomer research pertaining to some human amyloid diseases.
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Affiliation(s)
- Xinyu Zhou
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Yuling Zheng
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Qingyu Lv
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Decong Kong
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Bin Ji
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Xuelian Han
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Zeyu Sun
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Li Zhu
- Beijing Institute of Biotechnology, Beijing, China
| | - Peng Liu
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Hua Jiang
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Yongqiang Jiang
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
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11
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Dong Y, Miao X, Zheng YD, Liu J, He QY, Ge R, Sun X. Ciprofloxacin-Resistant Staphylococcus aureus Displays Enhanced Resistance and Virulence in Iron-Restricted Conditions. J Proteome Res 2021; 20:2839-2850. [PMID: 33872026 DOI: 10.1021/acs.jproteome.1c00077] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The unreasonable misuse of antibiotics has led to the emergence of large-scale drug-resistant bacteria, seriously threatening human health. Compared with drug-sensitive bacteria, resistant bacteria are difficult to clear by host immunity. To fully explore the adaptive mechanism of resistant bacteria to the iron-restricted environment, we performed data-independent acquisition-based quantitative proteomics on ciprofloxacin (CIP)-resistant (CIP-R) Staphylococcus aureus in the presence or absence of iron. On bioinformatics analysis, CIP-R bacteria showed stronger amino acid synthesis and energy storage ability. Notably, CIP-R bacteria increased virulence by upregulating the expression of many virulence-related proteins and enhancing the synthesis of virulence-related amino acids under iron-restricted stress. This study will help us to further explain the adaptive mechanisms that lead to bacterial resistance to antibiotics depending on the host environment and provide insights into the development of novel drugs for the treatment of drug-resistant bacterial infections.
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Affiliation(s)
- Yingshan Dong
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Xinyu Miao
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Yun-Dan Zheng
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Jiajia Liu
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Qing-Yu He
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Ruiguang Ge
- State Key Laboratory of Biocontrol, College of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Xuesong Sun
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
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12
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Sinha D, Sinha D, Dutta A, Chakraborty T, Mondal R, Seal S, Poddar A, Chatterjee S, Sau S. Alternative Sigma Factor of Staphylococcus aureus Interacts with the Cognate Antisigma Factor Primarily Using Its Domain 3. Biochemistry 2021; 60:135-151. [PMID: 33406357 DOI: 10.1021/acs.biochem.0c00881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
σB, an alternative sigma factor, is usually employed to tackle the general stress response in Staphylococcus aureus and other Gram-positive bacteria. This protein, involved in S. aureus-mediated pathogenesis, is typically blocked by RsbW, an antisigma factor having serine kinase activity. σB, a σ70-like sigma factor, harbors three conserved domains designated σB2, σB3, and σB4. To better understand the interaction between RsbW and σB or its domains, we have studied their recombinant forms, rRsbW, rσB, rσB2, rσB3, and rσB4, using different probes. The results show that none of the rσB domains, unlike rσB, showed binding to a cognate DNA in the presence of a core RNA polymerase. However, both rσB2 and rσB3, like rσB, interacted with rRsbW, and the order of their rRsbW binding affinity looks like rσB > rσB3 > rσB2. Furthermore, the reaction between rRsbW and rσB or rσB3 was exothermic and occurred spontaneously. rRsbW and rσB3 also associate with each other at a stoichiometry of 2:1, and different types of noncovalent bonds might be responsible for their interaction. A structural model of the RsbW-σB3 complex that has supported our experimental results indicated the binding of rσB3 at the putative dimeric interface of RsbW. A genetic study shows that the tentative dimer-forming region of RsbW is crucial for preserving its rσB binding ability, serine kinase activity, and dimerization ability. Additionally, a urea-induced equilibrium unfolding study indicated a notable thermodynamic stabilization of σB3 in the presence of RsbW. Possible implications of the stabilization data in drug discovery were discussed at length.
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Affiliation(s)
- Debabrata Sinha
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal 700054, India
| | - Debasmita Sinha
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal 700054, India
| | - Anindya Dutta
- Department of Biophysics, Bose Institute, Kolkata, West Bengal 700054, India
| | - Tushar Chakraborty
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal 700054, India
| | - Rajkrishna Mondal
- Department of Biotechnology, Nagaland University, Dimapur, Nagaland 797112, India
| | - Soham Seal
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal 700054, India
| | - Asim Poddar
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal 700054, India
| | | | - Subrata Sau
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal 700054, India
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13
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Martínez-García S, Peralta H, Betanzos-Cabrera G, Chavez-Galan L, Rodríguez-Martínez S, Cancino-Diaz ME, Cancino-Diaz JC. Proteomic comparison of biofilm vs. planktonic Staphylococcus epidermidis cells suggests key metabolic differences between these conditions. Res Microbiol 2021; 172:103796. [PMID: 33412274 DOI: 10.1016/j.resmic.2020.103796] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/22/2020] [Accepted: 12/24/2020] [Indexed: 11/16/2022]
Abstract
Previous studies have shown that biofilm-forming bacteria are deficient in tricarboxylic acid (TCA) cycle metabolites, suggesting a relationship between these cellular processes. In this work, we compared the proteomes of planktonic vs biofilm cells from a clinical strain of Staphylococcus epidermidis using LC-MS/MS. A total of 168 proteins were identified from both growth conditions. The biofilm cells showed enrichment of proteins participating in glycolysis for the formation of pyruvate; however, the absence of TCA cycle proteins and the presence of lactate dehydrogenase, formate acetyltransferase, and acetoin reductase suggested that pyruvate was catabolized to their respective products: lactate, formate and acetoin. On the other hand, planktonic cells showed proteins participating in glycolysis and the TCA cycle, the pentose phosphate pathway, gluconeogenesis, ATP generation and the oxidative stress response. Functional networks with higher interconnection were predicted for planktonic proteins. We propose that in S. epidermidis, the relative absence of TCA cycle proteins is associated with the formation of biofilms and that lactate, formate and acetoin are the end products of partial glucose metabolism.
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Affiliation(s)
- Sergio Martínez-García
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Cd. México, Mexico
| | - Humberto Peralta
- Functional Genomics of Prokaryotes, Center for Genomic Sciences, National University of Mexico, Cuernavaca, Morelos, Mexico
| | | | - Leslie Chavez-Galan
- Laboratory of Integrative Immunology, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Cd. México, Mexico
| | - Sandra Rodríguez-Martínez
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Cd. México, Mexico
| | - Mario E Cancino-Diaz
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Cd. México, Mexico.
| | - Juan C Cancino-Diaz
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Cd. México, Mexico.
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14
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Jenkins CL, Bean HD. Dependence of the Staphylococcal Volatilome Composition on Microbial Nutrition. Metabolites 2020; 10:metabo10090347. [PMID: 32867100 PMCID: PMC7569959 DOI: 10.3390/metabo10090347] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/16/2020] [Accepted: 08/23/2020] [Indexed: 01/09/2023] Open
Abstract
In vitro cultivation of staphylococci is fundamental to both clinical and research microbiology, but few studies, to-date, have investigated how the differences in rich media can influence the volatilome of cultivated bacteria. The objective of this study was to determine the influence of rich media composition on the chemical characteristics of the volatilomes of Staphylococcus aureus and Staphylococcus epidermidis. S. aureus (ATCC 12600) and S. epidermidis (ATCC 12228) were cultured in triplicate in four rich complex media (brain heart infusion (BHI), lysogeny broth (LB), Mueller Hinton broth (MHB), and tryptic soy broth (TSB)), and the volatile metabolites produced by each culture were analyzed using headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography—time-of-flight mass spectrometry (HS-SPME-GC×GC-TOFMS). When comparing the chemical compositions of the staph volatilomes by the presence versus absence of volatiles produced in each medium, we observed few differences. However, when the relative abundances of volatiles were included in the analyses, we observed that culturing staph in media containing free glucose (BHI and TSB) resulted in volatilomes dominated by acids and esters (67%). The low-glucose media (LB and MHB) produced ketones in greatest relative abundances, but the volatilome compositions in these two media were highly dissimilar. We conclude that the staphylococcal volatilome is strongly influenced by the nutritional composition of the growth medium, especially the availability of free glucose, which is much more evident when the relative abundances of the volatiles are analyzed, compared to the presence versus absence.
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Affiliation(s)
- Carrie L. Jenkins
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA;
- Center for Fundamental and Applied Microbiomics, The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Heather D. Bean
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA;
- Center for Fundamental and Applied Microbiomics, The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
- Correspondence:
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15
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A comprehensive review of bacterial osteomyelitis with emphasis on Staphylococcus aureus. Microb Pathog 2020; 148:104431. [PMID: 32801004 DOI: 10.1016/j.micpath.2020.104431] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/29/2020] [Accepted: 07/29/2020] [Indexed: 02/04/2023]
Abstract
Osteomyelitis, a significant infection of bone tissue, gives rise to two main groups of infection: acute and chronic. These groups are further categorized in terms of the duration of infection. Usually, children and adults are more susceptible to acute and chronic infections, respectively. The aforementioned groups of osteomyelitis share almost 80% of the corresponding bacterial pathogens. Among all bacteria, Staphylococcus aureus (S. aureus) is a significant pathogen and is associated with a high range of osteomyelitis symptoms. S. aureus has many strategies for interacting with host cells including Small Colony Variant (SCV), biofilm formation, and toxin secretion. In addition, it induces an inflammatory response and causes host cell death by apoptosis and necrosis. However, any possible step to take in this respect is dependent on the conditions and host responses. In the absence of any immune responses and antibiotics, bacteria actively duplicate themselves; however, in the presence of phagocytic cell and harassing conditions, they turn into a SCV, remaining sustainable for a long time. SCV is characterized by notable advantages such as (a) intracellular life that mediates a dam against immune cells and (b) low ATP production that mediates resistance against antibiotics.
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16
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Havlikova J, May RC, Styles IB, Cooper HJ. Direct identification of bacterial and human proteins from infected wounds in living 3D skin models. Sci Rep 2020; 10:11900. [PMID: 32681099 PMCID: PMC7368034 DOI: 10.1038/s41598-020-68233-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 06/19/2020] [Indexed: 11/23/2022] Open
Abstract
Trauma is one of the leading causes of death in people under the age of 49 and complications due to wound infection are the primary cause of death in the first few days after injury. The ESKAPE pathogens are a group of bacteria that are a leading cause of hospital-acquired infections and a major concern in terms of antibiotic resistance. Here, we demonstrate a novel and highly accurate approach for the rapid identification of ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) directly from infected wounds in 3D in vitro skin models. Wounded skin models were inoculated with bacteria and left to incubate. Bacterial proteins were identified within minutes, directly from the wound, by liquid extraction surface analysis mass spectrometry. This approach was able to distinguish closely related strains and, unlike genomic approaches, can be modified to provide dynamic information about pathogen behaviour at the wound site. In addition, since human skin proteins were also identified, this method offers the opportunity to analyse both host and pathogen biomarkers during wound infection in near real-time.
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Affiliation(s)
- Jana Havlikova
- EPSRC Centre for Doctoral Training in Physical Sciences for Health, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Robin C May
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Iain B Styles
- EPSRC Centre for Doctoral Training in Physical Sciences for Health, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,School of Computer Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,Centre of Membrane Proteins and Receptors, The Universities of Birmingham and Nottingham, The Midlands, Birmingham, UK.,Alan Turing Institute, 96 Euston Road, London, NW1 2DB, UK
| | - Helen J Cooper
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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17
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Jones DD, Caesar LK, Pelzer CV, Crandall WJ, Jenul C, Todd DA, Horswill AR, Cech NB. Targeted and untargeted analysis of secondary metabolites to monitor growth and quorum sensing inhibition for methicillin-resistant Staphylococcus aureus (MRSA). J Microbiol Methods 2020; 176:106000. [PMID: 32649968 DOI: 10.1016/j.mimet.2020.106000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/02/2020] [Accepted: 07/02/2020] [Indexed: 11/17/2022]
Abstract
Drug resistant infections are an increasing problem world-wide, responsible for an estimated 700,000 annual mortalities. The use of antibiotics to treat such infections has resulted in the development of resistant bacterial pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). One potential alternative strategy for treating drug resistant bacterial infections is to inhibit the production of toxins, thereby making the bacteria less harmful to the host, a so called "anti-virulence" approach. In MRSA, the agr quorum sensing system is one of the major regulators of toxin production, and quorum sensing inhibitors that target this system are a promising anti-virulence strategy. With this study, we developed a method that enables the activity of quorum sensing inhibitors to be measured using ultra-performance liquid chromatography coupled to mass spectrometry (UPLC-MS). This method is an improvement over existing methods because it can be employed to distinguish antimicrobial activity from quorum sensing inhibition activity based on the UPLC-MS data. This is possible by simultaneously tracking production of metabolites regulated by the agr quorum sensing system (AIP-I and formylated δ-toxin) and a metabolite that appears not to be agr regulated under the conditions of this study (aureusimine B). The newly developed method provides more nuanced indication of how metabolite production changes over time and in response to quorum sensing or growth inhibition than is possible with commonly employed spectroscopic methods.
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Affiliation(s)
- Derick D Jones
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Lindsay K Caesar
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Chantal V Pelzer
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, USA
| | - William J Crandall
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Christian Jenul
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Daniel A Todd
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA; Department of Veterans Affairs Eastern Colorado Health Care System, Aurora, CO, USA
| | - Nadja B Cech
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, USA.
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18
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Tan X, Ramond E, Jamet A, Barnier JP, Decaux-Tramoni B, Dupuis M, Euphrasie D, Tros F, Nemazanyy I, Ziveri J, Nassif X, Charbit A, Coureuil M. Transketolase of Staphylococcus aureus in the Control of Master Regulators of Stress Response During Infection. J Infect Dis 2020; 220:1967-1976. [PMID: 31420648 DOI: 10.1093/infdis/jiz404] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 08/07/2019] [Indexed: 12/31/2022] Open
Abstract
Staphylococcus aureus is a leading cause of both acute and chronic infections in humans. The importance of the pentose phosphate pathway (PPP) during S. aureus infection is currently largely unexplored. In the current study, we focused on one key PPP enzyme, transketolase (TKT). We showed that inactivation of the unique gene encoding TKT activity in S. aureus USA300 (∆tkt) led to drastic metabolomic changes. Using time-lapse video imaging and mice infection, we observed a major defect of the ∆tkt strain compared with wild-type strain in early intracellular proliferation and in the ability to colonize kidneys. Transcriptional activity of the 2 master regulators sigma B and RpiRc was drastically reduced in the ∆tkt mutant during host cells invasion. The concomitant increased RNAIII transcription suggests that TKT-or a functional PPP-strongly influences the ability of S. aureus to proliferate within host cells by modulating key transcriptional regulators.
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Affiliation(s)
- Xin Tan
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris
| | - Elodie Ramond
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris
| | - Anne Jamet
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris
| | - Jean-Philippe Barnier
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris
| | | | - Marion Dupuis
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris
| | - Daniel Euphrasie
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris
| | - Fabiola Tros
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris
| | - Ivan Nemazanyy
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris.,Plateforme Métabolomique Institut Necker, Structure Fédérative de Recherche Necker, Université Paris Descartes, France
| | - Jason Ziveri
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris
| | - Xavier Nassif
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris
| | - Alain Charbit
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris
| | - Mathieu Coureuil
- Université de Paris.,INSERM U1151-CNRS UMR 8253, Institut Necker-Enfants Malades, Paris
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19
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Host nutrient milieu drives an essential role for aspartate biosynthesis during invasive Staphylococcus aureus infection. Proc Natl Acad Sci U S A 2020; 117:12394-12401. [PMID: 32414924 PMCID: PMC7275739 DOI: 10.1073/pnas.1922211117] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus can infect a diverse array of host environments. The broad tissue tropism of S. aureus requires metabolic flexibility to utilize the variety of nutrient sources found within target organ systems. In this work, we conducted a systematic analysis of the central metabolic pathways required for S. aureus survival during bone infection, one of the most frequent sites of invasive staphylococcal disease. We show that S. aureus requires aspartate biosynthesis to survive during bone infection, despite possessing an aspartate transporter, due to inhibition of aspartate utilization by the amino acid glutamate. Our results reveal a crucial role for inflammation-associated shifts in the host nutrient milieu for determining the metabolic pathways utilized by S. aureus during invasive infection. The bacterial pathogen Staphylococcus aureus is capable of infecting a broad spectrum of host tissues, in part due to flexibility of metabolic programs. S. aureus, like all organisms, requires essential biosynthetic intermediates to synthesize macromolecules. We therefore sought to determine the metabolic pathways contributing to synthesis of essential precursors during invasive S. aureus infection. We focused specifically on staphylococcal infection of bone, one of the most common sites of invasive S. aureus infection and a unique environment characterized by dynamic substrate accessibility, infection-induced hypoxia, and a metabolic profile skewed toward aerobic glycolysis. Using a murine model of osteomyelitis, we examined survival of S. aureus mutants deficient in central metabolic pathways, including glycolysis, gluconeogenesis, the tricarboxylic acid (TCA) cycle, and amino acid synthesis/catabolism. Despite the high glycolytic demand of skeletal cells, we discovered that S. aureus requires glycolysis for survival in bone. Furthermore, the TCA cycle is dispensable for survival during osteomyelitis, and S. aureus instead has a critical need for anaplerosis. Bacterial synthesis of aspartate in particular is absolutely essential for staphylococcal survival in bone, despite the presence of an aspartate transporter, which we identified as GltT and confirmed biochemically. This dependence on endogenous aspartate synthesis derives from the presence of excess glutamate in infected tissue, which inhibits aspartate acquisition by S. aureus. Together, these data elucidate the metabolic pathways required for staphylococcal infection within bone and demonstrate that the host nutrient milieu can determine essentiality of bacterial nutrient biosynthesis pathways despite the presence of dedicated transporters.
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20
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Su M, Lyles JT, Petit III RA, Peterson J, Hargita M, Tang H, Solis-Lemus C, Quave CL, Read TD. Genomic analysis of variability in Delta-toxin levels between Staphylococcus aureus strains. PeerJ 2020; 8:e8717. [PMID: 32231873 PMCID: PMC7100594 DOI: 10.7717/peerj.8717] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 02/10/2020] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The delta-toxin (δ-toxin) of Staphylococcus aureus is the only hemolysin shown to cause mast cell degranulation and is linked to atopic dermatitis, a chronic inflammatory skin disease. We sought to characterize variation in δ-toxin production across S. aureus strains and identify genetic loci potentially associated with differences between strains. METHODS A set of 124 S. aureus strains was genome-sequenced and δ-toxin levels in stationary phase supernatants determined by high performance liquid chromatography (HPLC). SNPs and kmers were associated with differences in toxin production using four genome-wide association study (GWAS) methods. Transposon mutations in candidate genes were tested for their δ-toxin levels. We constructed XGBoost models to predict toxin production based on genetic loci discovered to be potentially associated with the phenotype. RESULTS The S. aureus strain set encompassed 40 sequence types (STs) in 23 clonal complexes (CCs). δ-toxin production ranged from barely detectable levels to >90,000 units, with a median of >8,000 units. CC30 had significantly lower levels of toxin production than average while CC45 and CC121 were higher. MSSA (methicillin sensitive) strains had higher δ-toxin production than MRSA (methicillin resistant) strains. Through multiple GWAS approaches, 45 genes were found to be potentially associated with toxicity. Machine learning models using loci discovered through GWAS as features were able to predict δ-toxin production (as a high/low binary phenotype) with a precision of .875 and specificity of .990 but recall of .333. We discovered that mutants in the carA gene, encoding the small chain of carbamoyl phosphate synthase, completely abolished toxin production and toxicity in Caenorhabditis elegans. CONCLUSIONS The amount of stationary phase production of the toxin is a strain-specific phenotype likely affected by a complex interaction of number of genes with different levels of effect. We discovered new candidate genes that potentially play a role in modulating production. We report for the first time that the product of the carA gene is necessary for δ-toxin production in USA300. This work lays a foundation for future work on understanding toxin regulation in S. aureus and prediction of phenotypes from genomic sequences.
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Affiliation(s)
- Michelle Su
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - James T. Lyles
- Center for the Study of Human Health, College of Arts and Sciences, Emory University, Atlanta, GA, United States of America
| | - Robert A. Petit III
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Jessica Peterson
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Michelle Hargita
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Huaqiao Tang
- Center for the Study of Human Health, College of Arts and Sciences, Emory University, Atlanta, GA, United States of America
| | - Claudia Solis-Lemus
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Cassandra L. Quave
- Center for the Study of Human Health, College of Arts and Sciences, Emory University, Atlanta, GA, United States of America
- Department of Dermatology, School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Timothy D. Read
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, Atlanta, GA, United States of America
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, United States of America
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21
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Abstract
Respiratory mutants, both naturally occurring and genetically constructed, have taught us about the importance of metabolism in influencing virulence factor production, persistence, and antibiotic resistance. As we learn more about small colony variants, we find that Staphylococcus aureus has many pathways to produce small colony variants, although the respiratory variants are the best described clinically and in the laboratory.
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22
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Yang CI, Hsieh HH, Shan SO. Timing and specificity of cotranslational nascent protein modification in bacteria. Proc Natl Acad Sci U S A 2019; 116:23050-23060. [PMID: 31666319 PMCID: PMC6859321 DOI: 10.1073/pnas.1912264116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The nascent polypeptide exit site of the ribosome is a crowded environment where multiple ribosome-associated protein biogenesis factors (RPBs) compete for the nascent polypeptide to influence their localization, folding, or quality control. Here we address how N-terminal methionine excision (NME), a ubiquitous process crucial for the maturation of over 50% of the bacterial proteome, occurs in a timely and selective manner in this crowded environment. In bacteria, NME is mediated by 2 essential enzymes, peptide deformylase (PDF) and methionine aminopeptidase (MAP). We show that the reaction of MAP on ribosome-bound nascent chains approaches diffusion-limited rates, allowing immediate methionine excision of optimal substrates after deformylation. Specificity is achieved by kinetic competition of NME with translation elongation and by regulation from other RPBs, which selectively narrow the processing time window for suboptimal substrates. A mathematical model derived from the data accurately predicts cotranslational NME efficiency in the cytosol. Our results demonstrate how a fundamental enzymatic activity is reshaped by its associated macromolecular environment to optimize both efficiency and selectivity, and provides a platform to study other cotranslational protein biogenesis pathways.
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Affiliation(s)
- Chien-I Yang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Hao-Hsuan Hsieh
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
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Tam K, Torres VJ. Staphylococcus aureus Secreted Toxins and Extracellular Enzymes. Microbiol Spectr 2019; 7:10.1128/microbiolspec.GPP3-0039-2018. [PMID: 30873936 PMCID: PMC6422052 DOI: 10.1128/microbiolspec.gpp3-0039-2018] [Citation(s) in RCA: 185] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Indexed: 02/06/2023] Open
Abstract
Staphylococcus aureus is a formidable pathogen capable of causing infections in different sites of the body in a variety of vertebrate animals, including humans and livestock. A major contribution to the success of S. aureus as a pathogen is the plethora of virulence factors that manipulate the host's innate and adaptive immune responses. Many of these immune modulating virulence factors are secreted toxins, cofactors for activating host zymogens, and exoenzymes. Secreted toxins such as pore-forming toxins and superantigens are highly inflammatory and can cause leukocyte cell death by cytolysis and clonal deletion, respectively. Coagulases and staphylokinases are cofactors that hijack the host's coagulation system. Exoenzymes, including nucleases and proteases, cleave and inactivate various immune defense and surveillance molecules, such as complement factors, antimicrobial peptides, and surface receptors that are important for leukocyte chemotaxis. Additionally, some of these secreted toxins and exoenzymes can cause disruption of endothelial and epithelial barriers through cell lysis and cleavage of junction proteins. A unique feature when examining the repertoire of S. aureus secreted virulence factors is the apparent functional redundancy exhibited by the majority of the toxins and exoenzymes. However, closer examination of each virulence factor revealed that each has unique properties that have important functional consequences. This chapter provides a brief overview of our current understanding of the major secreted virulence factors critical for S. aureus pathogenesis.
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Affiliation(s)
- Kayan Tam
- Department of Microbiology, New York University School of Medicine, Alexandria Center for Life Science, New York, NY 10016
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, Alexandria Center for Life Science, New York, NY 10016
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24
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Wang H, Kraus F, Popella P, Baykal A, Guttroff C, François P, Sass P, Plietker B, Götz F. The Polycyclic Polyprenylated Acylphloroglucinol Antibiotic PPAP 23 Targets the Membrane and Iron Metabolism in Staphylococcus aureus. Front Microbiol 2019; 10:14. [PMID: 30728811 PMCID: PMC6352742 DOI: 10.3389/fmicb.2019.00014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/07/2019] [Indexed: 11/13/2022] Open
Abstract
Recently, a series of endo-type B polycyclic polyprenylated acylphloroglucinols (PPAP) derivatives with high antimicrobial activities were chemically synthesized. One of the derivatives, PPAP 23, which showed high antimicrobial activity and low cytotoxicity, was chosen for further investigation of its bactericidal profiles and mode of action. PPAP 23 showed a better efficacy in killing methicillin resistant Staphylococcus aureus (MRSA) and decreasing the metabolic activity of 5-day-old biofilm cells than vancomycin. Moreover, S. aureus did not appear to develop resistance against PPAP 23. The antimicrobial mechanism of PPAP 23 was investigated by RNA-seq combined with phenotypic and biochemical approaches. RNA-seq suggested that PPAP 23 signaled iron overload to the bacterial cells because genes involved in iron transport were downregulated and iron storage gene was upregulated by PPAP 23. PPAP 23 affected the membrane integrity but did not induce pore formation; it inhibited bacterial respiration. PPAP 23 preferentially inhibited Fe–S cluster enzymes; it has a mild iron chelating activity and supplementation of exogenous iron attenuated its antimicrobial activity. PPAP 23 was more effective in inhibiting the growth of S. aureus under iron-restricted condition. The crystal structure of a benzylated analog of PPAP 23 showed a highly defined octahedral coordination of three PPAP ligands around a Fe (3+) core. This suggests that PPAPs are generally capable of iron chelation and are able to form defined stable complexes. PPAP 23 was found to induce reactive oxygen species (ROS) and oxidative stress. Fluorescence microscopic analysis showed that PPAP 23 caused an enlargement of the bacterial cells, perturbed the membrane, and dislocated the nucleoid. Taken together, we postulate that PPAP 23 interacts with the cytoplasmic membrane with its hydrophobic pocket and interferes with the iron metabolism to exert its antimicrobial activity in Staphylococcus aureus.
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Affiliation(s)
- Huanhuan Wang
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Frank Kraus
- Institut für Organische Chemie, Universität Stuttgart, Stuttgart, Germany
| | - Peter Popella
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Aslihan Baykal
- Institut für Organische Chemie, Universität Stuttgart, Stuttgart, Germany
| | - Claudia Guttroff
- Institut für Organische Chemie, Universität Stuttgart, Stuttgart, Germany
| | - Patrice François
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospital, Geneva, Switzerland
| | - Peter Sass
- Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Bernd Plietker
- Institut für Organische Chemie, Universität Stuttgart, Stuttgart, Germany
| | - Friedrich Götz
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
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25
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Wu X, Yang M, Fang X, Zhen S, Zhang J, Yang X, Qiao L, Yang Y, Zhang C. Expression and regulation of phenol-soluble modulins and enterotoxins in foodborne Staphylococcus aureus. AMB Express 2018; 8:187. [PMID: 30467730 PMCID: PMC6250609 DOI: 10.1186/s13568-018-0717-x] [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: 07/18/2018] [Accepted: 11/17/2018] [Indexed: 12/15/2022] Open
Abstract
Although high levels of staphylococcal phenol-soluble modulins (PSMs) in clinical methicillin-resistant Staphylococcus aureus (MRSA) has been shown to correlate with bacterial virulence, the PSMs expression in foodborne Staphylococcus aureus (S. aureus), as well as its association with staphylococcal food poisoning (SFP) was not yet clear. We collected a panel of 350 foodborne and 127 clinic-derived S. aureus strains and compared their PSMs expression. Overall, foodborne strains exhibited higher PSMs than clinical isolates, indicating a potential pathological significance of PSMs in staphylococcal food contamination. Furthermore, PSMs expression and staphylococcal enterotoxins (SEs) levels in relation to antibiotic sensitive and resistant strains were analysed. While the co-expression of PSMs and SEs was confirmed, one typical foodborne strain simultaneously yielding PSMs, SEB and SED was selected. By comparing this wildtype strain to a series of gene-deficient mutants, we concluded that PSMs and SEs expressions both relied on staphylococcal accessory regulator A initiation in the early stage of accessory gene regulator control, yet their succedent regulations differentiated to RNAIII-dependent and independent, respectively. These data provided preliminary insight into PSMs and SEs expression in foodborne S. aureus, and may guide the further studies on PSMs effects in SFP.
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26
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Montanaro L, Campoccia D, Arciola CR. A Glance at the Role of Exotoxins in Opportunistic Bacterial Infections. Int J Artif Organs 2018; 29:462-7. [PMID: 16705616 DOI: 10.1177/039139880602900417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The production and the mechanism of action of exotoxins from Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa are presented. The attack to the immune host's defenses is the main virulence factor of opportunistic bacteria in implant infections, favoring the invasion and colonization of compromised periprosthesis tissues.
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Affiliation(s)
- L Montanaro
- Research Laboratory on Biocompatibility of Implant Materials, Rizzoli Orthopedic Institute, Bologna and Experimental Pathology Department, University of Bologna, Italy.
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Swarupa V, Chaudhury A, Sarma PVGK. Iron enhances the peptidyl deformylase activity and biofilm formation in Staphylococcus aureus. 3 Biotech 2018; 8:32. [PMID: 29291145 DOI: 10.1007/s13205-017-1050-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 12/17/2017] [Indexed: 11/30/2022] Open
Abstract
Staphylococcus aureus plays a major role in persistent infections and many of these species form structured biofilms on different surfaces which is accompanied by changes in gene expression profiles. Further, iron supplementation plays a critical role in the regulation of several protein(s)/enzyme function, which all aid in the development of active bacterial biofilms. It is well known that for each protein, deformylation is the most crucial step in biosynthesis and is catalyzed by peptidyl deformylase (PDF). Thus, the aim of the current study is to understand the role of iron in biofilm formation and deformylase activity of PDF. Hence, the PDF gene of S. aureus ATCC12600 was PCR amplified using specific primers and sequenced, followed by cloning and expression in Escherichia coli DH5α. The deformylase activity of the purified recombinant PDF was measured in culture supplemented with/without iron where the purified rPDF showed Km of 1.3 mM and Vmax of 0.035 mM/mg/min, which was close to the native PDF (Km = 1.4 mM, Vmax = 0.030 mM/mg/min). Interestingly, the Km decreased and PDF activity increased when the culture was supplemented with iron, corroborating with qPCR results showing 100- to 150-fold more expression compared to control in S. aureus and its drug-resistant strains. Further biofilm-forming units (BU) showed an incredible increase (0.42 ± 0.005 to 6.3 ± 0.05 BU), i.e., almost 15-fold elevation in anaerobic conditions, indicating the significance of iron in S. aureus biofilms.
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Affiliation(s)
- Vimjam Swarupa
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, 517507 AP India
| | - Abhijit Chaudhury
- Department of Microbiology, Sri Venkateswara Institute of Medical Sciences, Tirupati, 517507 India
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28
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Prasad UV, Vasu D, Gowtham RR, Pradeep CK, Swarupa V, Yeswanth S, Choudhary A, Sarma PVGK. Cloning, Expression and Characterization of NAD Kinase from Staphylococcus aureus Involved in the Formation of NADP (H): A Key Molecule in the Maintaining of Redox Status and Biofilm Formation. Adv Biomed Res 2017; 6:97. [PMID: 28828348 PMCID: PMC5549544 DOI: 10.4103/2277-9175.211833] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Staphylococcus aureus has the ability to form biofilms on any niches, a key pathogenic factor of this organism and this phenomenon is directly related to the concentration of NADPH. The formation of NADP is catalyzed by NAD kinase (NADK) and this gene of S. aureus ATCC 12600 was cloned, sequenced, expressed and characterized. MATERIALS AND METHODS The NADK gene was polymerase chain reaction amplified from the chromosomal DNA of S. aureus ATCC 12600 and cloned in pQE 30 vector, sequenced and expressed in Escherichia coli DH5α. The pure protein was obtained by passing through nickel metal chelate agarose column. The enzyme kinetics of the enzyme and biofilm assay of the S. aureus was carried out in both aerobic and anaerobic conditions. The kinetics was further confirmed by the ability of the substrates to dock to the NADK structure. RESULTS The recombinant NADK exhibited single band with a molecular weight of 31kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the gene sequence (GenBank: JN645814) revealed presence of only one kind of NADK in all S. aureus strains. The enzyme exhibited very high affinity for NAD compared to adenosine triphosphate concurring with the docking results. A root-mean-square deviation value 14.039Å observed when NADK structure was superimposed with its human counterpart suggesting very low homology. In anaerobic conditions, higher biofilm units were found with decreased NADK activity. CONCLUSION The results of this study suggest increased NADPH concentration in S. aureus plays a vital role in the biofilm formation and survival of this pathogen in any environmental conditions.
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Affiliation(s)
- U Venkateswara Prasad
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
| | - D Vasu
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
| | - R Rishi Gowtham
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
| | - Ch Krishna Pradeep
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
| | - V Swarupa
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
| | - S Yeswanth
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
| | - Abhijit Choudhary
- Department of Microbiology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
| | - P V G K Sarma
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
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Pollitt EJG, Diggle SP. Defining motility in the Staphylococci. Cell Mol Life Sci 2017; 74:2943-2958. [PMID: 28378043 PMCID: PMC5501909 DOI: 10.1007/s00018-017-2507-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 02/16/2017] [Accepted: 03/14/2017] [Indexed: 01/17/2023]
Abstract
The ability of bacteria to move is critical for their survival in diverse environments and multiple ways have evolved to achieve this. Two forms of motility have recently been described for Staphylococcus aureus, an organism previously considered to be non-motile. One form is called spreading, which is a type of sliding motility and the second form involves comet formation, which has many observable characteristics associated with gliding motility. Darting motility has also been observed in Staphylococcus epidermidis. This review describes how motility is defined and how we distinguish between passive and active motility. We discuss the characteristics of the various forms of Staphylococci motility, the molecular mechanisms involved and the potential future research directions.
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Affiliation(s)
- Eric J G Pollitt
- Department of Biomedical Science, Western Bank, University of Sheffield, Sheffield, UK
| | - Stephen P Diggle
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
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30
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Effect of decreased BCAA synthesis through disruption of ilvC gene on the virulence of Streptococcus pneumoniae. Arch Pharm Res 2017; 40:921-932. [PMID: 28735462 DOI: 10.1007/s12272-017-0931-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
Streptococcus pneumoniae (pneumococcus) is responsible for significant morbidity and mortality worldwide. It causes a variety of life-threatening infections such as pneumonia, bacteremia, and meningitis. In bacterial physiology, the metabolic pathway of branched-chain amino acids (BCAAs) plays an important role in virulence. Nonetheless, the function of IlvC, one of the enzymes involved in the biosynthesis of BCAAs, in S. pneumoniae remains unclear. Here, we demonstrated that downregulation of BCAA biosynthesis by ilvC ablation can diminish BCAA concentration and expression of pneumolysin (Ply) and LytA, and subsequently attenuate virulence. Infection with an ilvC mutant showed significantly reduced mortality and colonization in comparison with strain D39 (serotype 2, wild type), suggesting that ilvC can potentiate S. pneumoniae virulence due to adequate BCAA synthesis. Taken together, these results suggest that the function of ilvC in BCAA synthesis is essential for virulence factor and could play an important role in the pathogenesis of respiratory infections.
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Janesch P, Rouha H, Weber S, Malafa S, Gross K, Maierhofer B, Badarau A, Visram ZC, Stulik L, Nagy E. Selective sensitization of human neutrophils to LukGH mediated cytotoxicity by Staphylococcus aureus and IL-8. J Infect 2017; 74:473-483. [PMID: 28237625 DOI: 10.1016/j.jinf.2017.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 02/14/2017] [Accepted: 02/17/2017] [Indexed: 01/03/2023]
Abstract
OBJECTIVES Staphylococcus aureus produces up to five bi-component leukocidins - LukSF-PV, gamma-hemolysins AB and CB, LukGH (LukAB) and LukED - to evade innate immunity by lysing phagocytic cells. Species specificity of these leukocidins limits the relevance of animal models, therefore we assessed their individual contribution using human neutrophils. METHODS Human polymorphonuclear leukocytes (PMNs) were activated with stimuli relevant during bacterial infections and sensitivity to recombinant leukocidins was measured in cell-viability assays. Leukocidin receptor expression was quantified by flow cytometry. RESULTS We observed greatly variable sensitivities of different PMN preparations towards LukGH. Activation of PMNs by lipopolysaccharide (LPS) or S. aureus culture supernatant (CS) lacking all leukocidins resulted in higher surface expression of CD11b, the LukGH receptor, and greatly enhanced the sensitivity towards LukGH, eliminating the variability observed with unstimulated cells. In contrast, CS induced a decrease in sensitivity of PMNs to the other four leukocidins and reduced surface staining for their cognate receptors (CXCR1, CXCR2, C5aR, C5L2). Delta-toxin and peptidoglycan mimicked the effect of CS. Moreover, IL-8, an important cytokine in neutrophil activation, also selectively increased LukGH sensitivity. Deletion of lukGH, but not other leukocidin genes, prevented PMN killing upon infection with USA300 CA-MRSA. CONCLUSION Inflammatory signals enhance the susceptibility of human PMNs to lysis by LukGH rendering this toxin dominant among the S. aureus leukocidins in vitro.
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RpiRc Is a Pleiotropic Effector of Virulence Determinant Synthesis and Attenuates Pathogenicity in Staphylococcus aureus. Infect Immun 2016; 84:2031-2041. [PMID: 27113358 DOI: 10.1128/iai.00285-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 04/17/2016] [Indexed: 12/16/2022] Open
Abstract
In Staphylococcus aureus, metabolism is intimately linked with virulence determinant biosynthesis, and several metabolite-responsive regulators have been reported to mediate this linkage. S. aureus possesses at least three members of the RpiR family of transcriptional regulators. Of the three RpiR homologs, RpiRc is a potential regulator of the pentose phosphate pathway, which also regulates RNAIII levels. RNAIII is the regulatory RNA of the agr quorum-sensing system that controls virulence determinant synthesis. The effect of RpiRc on RNAIII likely involves other regulators, as the regulators that bind the RNAIII promoter have been intensely studied. To determine which regulators might bridge the gap between RpiRc and RNAIII, sarA, sigB, mgrA, and acnA mutations were introduced into an rpiRc mutant background, and the effects on RNAIII were determined. Additionally, phenotypic and genotypic differences were examined in the single and double mutant strains, and the virulence of select strains was examined using two different murine infection models. The data suggest that RpiRc affects RNAIII transcription and the synthesis of virulence determinants in concert with σ(B), SarA, and the bacterial metabolic status to negatively affect virulence.
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Abstract
Pathogenic bacteria must contend with immune systems that actively restrict the availability of nutrients and cofactors, and create a hostile growth environment. To deal with these hostile environments, pathogenic bacteria have evolved or acquired virulence determinants that aid in the acquisition of nutrients. This connection between pathogenesis and nutrition may explain why regulators of metabolism in nonpathogenic bacteria are used by pathogenic bacteria to regulate both metabolism and virulence. Such coordinated regulation is presumably advantageous because it conserves carbon and energy by aligning synthesis of virulence determinants with the nutritional environment. In Gram-positive bacterial pathogens, at least three metabolite-responsive global regulators, CcpA, CodY, and Rex, have been shown to coordinate the expression of metabolism and virulence genes. In this chapter, we discuss how environmental challenges alter metabolism, the regulators that respond to this altered metabolism, and how these regulators influence the host-pathogen interaction.
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Quave CL, Lyles JT, Kavanaugh JS, Nelson K, Parlet CP, Crosby HA, Heilmann KP, Horswill AR. Castanea sativa (European Chestnut) Leaf Extracts Rich in Ursene and Oleanene Derivatives Block Staphylococcus aureus Virulence and Pathogenesis without Detectable Resistance. PLoS One 2015; 10:e0136486. [PMID: 26295163 PMCID: PMC4546677 DOI: 10.1371/journal.pone.0136486] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 08/04/2015] [Indexed: 01/08/2023] Open
Abstract
The Mediterranean is home to a rich history of medical traditions that have developed under the influence of diverse cultures over millennia. Today, many such traditions are still alive in the folk medical practices of local people. Investigation of botanical folk medicines used in the treatment of skin and soft tissue infections led us to study Castanea sativa (European Chestnut) for its potential antibacterial activity. Here, we report the quorum sensing inhibitory activity of refined and chemically characterized European Chestnut leaf extracts, rich in oleanene and ursene derivatives (pentacyclic triterpenes), against all Staphylococcus aureus accessory gene regulator (agr) alleles. We present layers of evidence of agr blocking activity (IC50 1.56–25 μg mL-1), as measured in toxin outputs, reporter assays hemolytic activity, cytotoxicity studies, and an in vivo abscess model. We demonstrate the extract’s lack of cytotoxicity to human keratinocytes and murine skin, as well as lack of growth inhibitory activity against S. aureus and a panel of skin commensals. Lastly, we demonstrate that serial passaging of the extract does not result in acquisition of resistance to the quorum quenching composition. In conclusion, through disruption of quorum sensing in the absence of growth inhibition, this study provides insight into the role that non-biocide inhibitors of virulence may play in future antibiotic therapies.
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Affiliation(s)
- Cassandra L. Quave
- Center for the Study of Human Health, Emory University, Atlanta, Georgia, United States of America
- Department of Dermatology, Emory University School of Medicine, Atlanta, Georgia, United States of America
- * E-mail:
| | - James T. Lyles
- Center for the Study of Human Health, Emory University, Atlanta, Georgia, United States of America
| | - Jeffery S. Kavanaugh
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Kate Nelson
- Department of Dermatology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Corey P. Parlet
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Heidi A. Crosby
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Kristopher P. Heilmann
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Alexander R. Horswill
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
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Venkateswara Prasad U, Vasu D, Yeswanth S, Swarupa V, Sunitha MM, Choudhary A, Sarma PVGK. Phosphorylation controls the functioning ofStaphylococcus aureusisocitrate dehydrogenase – favours biofilm formation. J Enzyme Inhib Med Chem 2015; 30:655-61. [DOI: 10.3109/14756366.2014.959945] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Bloes DA, Kretschmer D, Peschel A. Enemy attraction: bacterial agonists for leukocyte chemotaxis receptors. Nat Rev Microbiol 2014; 13:95-104. [PMID: 25534805 DOI: 10.1038/nrmicro3390] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The innate immune system recognizes conserved microorganism-associated molecular patterns (MAMPs), some of which are sensed by G protein-coupled receptors (GPCRs), and this leads to chemotactic leukocyte influx. Recent studies have indicated that these processes are crucial for host defence and rely on a larger set of chemotactic MAMPs and corresponding GPCRs than was previously thought. Agonists, such as bacterial formyl peptides, enterococcal pheromone peptides, staphylococcal peptide toxins, bacterial fermentation products and the Helicobacter pylori peptide HP(2-20), stimulate specific GPCRs. The importance of leukocyte chemotaxis in host defence is highlighted by the fact that some bacterial pathogens produce chemotaxis inhibitors. How the various chemoattractants, receptors and antagonists shape antibacterial host defence represents an important topic for future research.
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Affiliation(s)
- Dominik Alexander Bloes
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Dorothee Kretschmer
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Andreas Peschel
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
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Quave CL, Horswill AR. Flipping the switch: tools for detecting small molecule inhibitors of staphylococcal virulence. Front Microbiol 2014; 5:706. [PMID: 25566220 PMCID: PMC4264471 DOI: 10.3389/fmicb.2014.00706] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 11/27/2014] [Indexed: 11/25/2022] Open
Abstract
Through the expression of the accessory gene regulator quorum sensing cascade, Staphylococcus aureus is able to produce an extensive array of enzymes, hemolysins and immunomodulators essential to its ability to spread through the host tissues and cause disease. Many have argued for the discovery and development of quorum sensing inhibitors (QSIs) to augment existing antibiotics as adjuvant therapies. Here, we discuss the state-of-the-art tools that can be used to conduct screens for the identification of such QSIs. Examples include fluorescent reporters, MS-detection of autoinducing peptide production, agar plate methods for detection of hemolysins and lipase, High performance liquid chromatography-detection of hemolysins from supernatants, and cell-toxicity assays for detecting damage (or relief thereof) against human keratinocyte cells. In addition to providing a description of these various approaches, we also discuss their amenability to low-, medium-, and high-throughput screening efforts for the identification of novel QSIs.
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Affiliation(s)
- Cassandra L Quave
- Department of Dermatology, Emory University School of Medicine Atlanta, GA, USA ; Center for the Study of Human Health, Emory University College of Arts and Sciences Atlanta, GA, USA
| | - Alexander R Horswill
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa Iowa City, IA, USA
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Hartmann T, Baronian G, Nippe N, Voss M, Schulthess B, Wolz C, Eisenbeis J, Schmidt-Hohagen K, Gaupp R, Sunderkötter C, Beisswenger C, Bals R, Somerville GA, Herrmann M, Molle V, Bischoff M. The catabolite control protein E (CcpE) affects virulence determinant production and pathogenesis of Staphylococcus aureus. J Biol Chem 2014; 289:29701-11. [PMID: 25193664 DOI: 10.1074/jbc.m114.584979] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Carbon metabolism and virulence determinant production are often linked in pathogenic bacteria, and several regulatory elements have been reported to mediate this linkage in Staphylococcus aureus. Previously, we described a novel protein, catabolite control protein E (CcpE) that functions as a regulator of the tricarboxylic acid cycle. Here we demonstrate that CcpE also regulates virulence determinant biosynthesis and pathogenesis. Specifically, deletion of ccpE in S. aureus strain Newman revealed that CcpE affects transcription of virulence factors such as capA, the first gene in the capsule biosynthetic operon; hla, encoding α-toxin; and psmα, encoding the phenol-soluble modulin cluster α. Electrophoretic mobility shift assays demonstrated that CcpE binds to the hla promoter. Mice challenged with S. aureus strain Newman or its isogenic ΔccpE derivative revealed increased disease severity in the ΔccpE mutant using two animal models; an acute lung infection model and a skin infection model. Complementation of the mutant with the ccpE wild-type allele restored all phenotypes, demonstrating that CcpE is negative regulator of virulence in S. aureus.
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Affiliation(s)
- Torsten Hartmann
- From the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Grégory Baronian
- the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université Montpellier 2, CNRS, UMR 5235, 34090 Montpellier, France
| | - Nadine Nippe
- the Institute of Immunology, University of Münster, 48149 Münster, Germany
| | - Meike Voss
- the Department of Internal Medicine V-Pulmonology, Allergology and Critical Care Medicine, Saarland University Medical Centre, 66421 Homburg/Saar, Germany
| | - Bettina Schulthess
- the Institute of Medical Microbiology, University of Zürich, 8006 Zürich, Switzerland
| | - Christiane Wolz
- the Institute of Medical Microbiology and Hygiene, University Hospital of Tübingen, 72076 Tübingen, Germany
| | - Janina Eisenbeis
- From the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Kerstin Schmidt-Hohagen
- the Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Rosmarie Gaupp
- From the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Cord Sunderkötter
- the Department of Dermatology, University of Münster, 48149 Münster, Germany, and
| | - Christoph Beisswenger
- the Department of Internal Medicine V-Pulmonology, Allergology and Critical Care Medicine, Saarland University Medical Centre, 66421 Homburg/Saar, Germany
| | - Robert Bals
- the Department of Internal Medicine V-Pulmonology, Allergology and Critical Care Medicine, Saarland University Medical Centre, 66421 Homburg/Saar, Germany
| | - Greg A Somerville
- the School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska 68583-0903
| | - Mathias Herrmann
- From the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Virginie Molle
- the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université Montpellier 2, CNRS, UMR 5235, 34090 Montpellier, France
| | - Markus Bischoff
- From the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany,
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Islam N, Kim Y, Ross JM, Marten MR. Proteomic analysis of Staphylococcus aureus biofilm cells grown under physiologically relevant fluid shear stress conditions. Proteome Sci 2014; 12:21. [PMID: 24855455 PMCID: PMC4013085 DOI: 10.1186/1477-5956-12-21] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 04/17/2014] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The biofilm forming bacterium Staphylococcus aureus is responsible for maladies ranging from severe skin infection to major diseases such as bacteremia, endocarditis and osteomyelitis. A flow displacement system was used to grow S. aureus biofilms in four physiologically relevant fluid shear rates (50, 100, 500 and 1000 s(-1)) to identify proteins that are associated with biofilm. RESULTS Global protein expressions from the membrane and cytosolic fractions of S. aureus biofilm cells grown under the above shear rate conditions are reported. Sixteen proteins in the membrane-enriched fraction and eight proteins in the cytosolic fraction showed significantly altered expression (p < 0.05) under increasing fluid shear. These 24 proteins were identified using nano-LC-ESI-MS/MS. They were found to be associated with various metabolic functions such as glycolysis / TCA pathways, protein synthesis and stress tolerance. Increased fluid shear stress did not influence the expression of two important surface binding proteins: fibronectin-binding and collagen-binding proteins. CONCLUSIONS The reported data suggest that while the general metabolic function of the sessile bacteria is minimal under high fluid shear stress conditions, they seem to retain the binding capacity to initiate new infections.
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Affiliation(s)
- Nazrul Islam
- Current address: Department of Plant Sciences, University of Maryland, College Park, MD 20742, USA
| | - Yonghyun Kim
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Julia M Ross
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County (UMBC), Baltimore, MD 21250, USA
| | - Mark R Marten
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County (UMBC), Baltimore, MD 21250, USA
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Influence of iron and aeration on Staphylococcus aureus growth, metabolism, and transcription. J Bacteriol 2014; 196:2178-89. [PMID: 24706736 DOI: 10.1128/jb.01475-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus is a prominent nosocomial pathogen and a major cause of biomaterial-associated infections. The success of S. aureus as a pathogen is due in part to its ability to adapt to stressful environments. As an example, the transition from residing in the nares to residing in the blood or deeper tissues is accompanied by changes in the availability of nutrients and elements such as oxygen and iron. As such, nutrients, oxygen, and iron are important determinants of virulence factor synthesis in S. aureus. In addition to influencing virulence factor synthesis, oxygen and iron are critical cofactors in enzymatic and electron transfer reactions; thus, a change in iron or oxygen availability alters the bacterial metabolome. Changes in metabolism create intracellular signals that alter the activity of metabolite-responsive regulators such as CodY, RpiRc, and CcpA. To assess the extent of metabolomic changes associated with oxygen and iron limitation, S. aureus cells were cultivated in iron-limited medium and/or with decreasing aeration, and the metabolomes were examined by nuclear magnetic resonance (NMR) spectroscopy. As expected, oxygen and iron limitation dramatically decreased tricarboxylic acid (TCA) cycle activity, creating a metabolic block and significantly altering the metabolome. These changes were most prominent during post-exponential-phase growth, when TCA cycle activity was maximal. Importantly, many of the effects of iron limitation were obscured by aeration limitation. Aeration limitation not only obscured the metabolic effects of iron limitation but also overrode the transcription of iron-regulated genes. Finally, in contrast to previous speculation, we confirmed that acidification of the culture medium occurs independent of the availability of iron.
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Prasad UV, Swarupa V, Yeswanth S, Kumar PS, Kumar ES, Reddy KMK, Kumar YN, Rani VJ, Chaudhary A, Sarma PVGK. Structural and Functional analysis of Staphylococcus aureus NADP-dependent IDH and its comparison with Bacterial and Human NADPdependent IDH. Bioinformation 2014; 10:81-6. [PMID: 24616559 PMCID: PMC3937580 DOI: 10.6026/97320630010081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 01/31/2014] [Indexed: 01/14/2023] Open
Abstract
Staphylococcus aureus a natural inhabitant of nasopharyngeal tract mainly survives as biofilms and possess complete Krebs cycle which plays major role in its pathogenesis. This TCA cycle is regulated by Isocitrate dehydrogenase (IDH) we have earlier cloned, sequenced (HM067707), expressed and characterized this enzyme from S. aureus ATCC12600. We have observed only one type of IDH in all the strains of S. aureus which dictates the flow of carbon thereby controlling the virulence and biofilm formation, this phenomenon is variable among bacteria. Therefore in the present study comparative structural and functional analysis of IDH was undertaken. As the crystal structure of S. aureus IDH was not available therefore using the deduced amino sequence of complete gene the 3D structure of IDH was built in Modeller 9v8. The PROCHECK and ProSAweb analysis showed the built structure was close to the crystal structure of Bacillus subtilis. This structure when superimposed with other bacterial IDH structures exhibited extensive structural variations as evidenced from the RMSD values correlating with extensive sequential variations. Only 24% sequence identity was observed with both human NADP dependent IDHs (PDB: 1T09 and 1T0L) and the structural comparative studies indicated extensive structural variations with an RMSD values of 14.284Å and 10.073Å respectively. Docking of isocitrate to both human IDHs and S. aureus IDH structures showed docking scores of -11.6169 and -10.973 respectively clearly indicating higher binding affinity of isocitrate to human IDH.
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Affiliation(s)
- Uppu Venkateswara Prasad
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, AP, India, 517507
| | - Vimjam Swarupa
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, AP, India, 517507
| | - Sthanikam Yeswanth
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, AP, India, 517507
| | - Pasupuleti Santhosh Kumar
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, AP, India, 517507
| | - Easambadi Siva Kumar
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati, AP, India, 517507
| | | | - Yellapu Nanda Kumar
- Department of Zoology, Sri Venkateswara University, Tirupati, AP, India, 517502
| | | | - Abhijit Chaudhary
- Department of Microbiology, Sri Venkateswara Institute of Medical Sciences, Tirupati - 517 507
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42
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Christiansen MT, Kaas RS, Chaudhuri RR, Holmes MA, Hasman H, Aarestrup FM. Genome-wide high-throughput screening to investigate essential genes involved in methicillin-resistant Staphylococcus aureus Sequence Type 398 survival. PLoS One 2014; 9:e89018. [PMID: 24563689 PMCID: PMC3923074 DOI: 10.1371/journal.pone.0089018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 01/14/2014] [Indexed: 02/06/2023] Open
Abstract
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) Sequence Type 398 (ST398) is an opportunistic pathogen that is able to colonize and cause disease in several animal species including humans. To better understand the adaptation, evolution, transmission and pathogenic capacity, further investigations into the importance of the different genes harboured by LA-MRSA ST398 are required. In this study we generated a genome-wide transposon mutant library in an LA-MRSA ST398 isolate to evaluate genes important for bacterial survival in laboratory and host-specific environments. The transposon mutant library consisted of approximately 1 million mutants with around 140,000 unique insertion sites and an average number of unique inserts per gene of 44.8. We identified LA-MRSA ST398 essential genes comparable to other high-throughput S. aureus essential gene studies. As ST398 is the most common MRSA isolated from pigs, the transposon mutant library was screened in whole porcine blood. Twenty-four genes were specifically identified as important for bacterial survival in porcine blood. Mutations in 23 of these genes resulted in attenuated bacterial fitness. Seven of the 23 genes were of unknown function, whereas 16 genes were annotated with functions predominantly related to carbon metabolism, pH shock and a variety of regulations and only indirectly to virulence factors. Mutations in one gene of unknown function resulted in a hypercompetitive mutant. Further evaluation of these genes is required to determine their specific relevance in blood survival.
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Affiliation(s)
- Mette T. Christiansen
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
- * E-mail: (MTC); (FMA)
| | - Rolf S. Kaas
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Roy R. Chaudhuri
- Department of Veterinary Medicine, University of Cambridge, Cambridge, England, United Kingdom
| | - Mark A. Holmes
- Department of Veterinary Medicine, University of Cambridge, Cambridge, England, United Kingdom
| | - Henrik Hasman
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Frank M. Aarestrup
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
- * E-mail: (MTC); (FMA)
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43
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Chua KYL, Monk IR, Lin YH, Seemann T, Tuck KL, Porter JL, Stepnell J, Coombs GW, Davies JK, Stinear TP, Howden BP. Hyperexpression of α-hemolysin explains enhanced virulence of sequence type 93 community-associated methicillin-resistant Staphylococcus aureus. BMC Microbiol 2014; 14:31. [PMID: 24512075 PMCID: PMC3922988 DOI: 10.1186/1471-2180-14-31] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 02/05/2014] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The community-associated methicillin-resistant S. aureus (CA-MRSA) ST93 clone is becoming dominant in Australia and is clinically highly virulent. In addition, sepsis and skin infection models demonstrate that ST93 CA-MRSA is the most virulent global clone of S. aureus tested to date. While the determinants of virulence have been studied in other clones of CA-MRSA, the basis for hypervirulence in ST93 CA-MRSA has not been defined. RESULTS Here, using a geographically and temporally dispersed collection of ST93 isolates we demonstrate that the ST93 population hyperexpresses key CA-MRSA exotoxins, in particular α-hemolysin, in comparison to other global clones. Gene deletion and complementation studies, and virulence comparisons in a murine skin infection model, showed unequivocally that increased expression of α-hemolysin is the key staphylococcal virulence determinant for this clone. Genome sequencing and comparative genomics of strains with divergent exotoxin profiles demonstrated that, like other S. aureus clones, the quorum sensing agr system is the master regulator of toxin expression and virulence in ST93 CA-MRSA. However, we also identified a previously uncharacterized AraC/XylS family regulator (AryK) that potentiates toxin expression and virulence in S. aureus. CONCLUSIONS These data demonstrate that hyperexpression of α-hemolysin mediates enhanced virulence in ST93 CA-MRSA, and additional control of exotoxin production, in particular α-hemolysin, mediated by regulatory systems other than agr have the potential to fine-tune virulence in CA-MRSA.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Benjamin P Howden
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria 3052, Australia.
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44
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Cheung GYC, Joo HS, Chatterjee SS, Otto M. Phenol-soluble modulins--critical determinants of staphylococcal virulence. FEMS Microbiol Rev 2014; 38:698-719. [PMID: 24372362 DOI: 10.1111/1574-6976.12057] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 12/05/2013] [Accepted: 12/19/2013] [Indexed: 10/25/2022] Open
Abstract
Phenol-soluble modulins (PSMs) are a recently discovered family of amphipathic, alpha-helical peptides that have multiple roles in staphylococcal pathogenesis and contribute to a large extent to the pathogenic success of virulent staphylococci, such as Staphylococcus aureus. PSMs may cause lysis of many human cell types including leukocytes and erythrocytes, stimulate inflammatory responses, and contribute to biofilm development. PSMs appear to have an original role in the commensal lifestyle of staphylococci, where they facilitate growth and spreading on epithelial surfaces. Aggressive, cytolytic PSMs seem to have evolved from that original role and are mainly expressed in highly virulent S. aureus. Here, we will review the biochemistry, genetics, and role of PSMs in the commensal and pathogenic lifestyles of staphylococci, discuss how diversification of PSMs defines the aggressiveness of staphylococcal species, and evaluate potential avenues to target PSMs for drug development against staphylococcal infections.
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Affiliation(s)
- Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, MD, USA
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45
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Abstract
Staphylococcus aureus is an important human pathogen and a leading cause of death worldwide. Phenol-soluble modulins (PSMs) have recently emerged as a novel toxin family defining the virulence potential of highly aggressive S. aureus isolates. PSMs have multiple roles in staphylococcal pathogenesis, causing lysis of red and white blood cells, stimulating inflammatory responses and contributing to biofilm development and the dissemination of biofilm-associated infections. Moreover, the pronounced capacity of PSMs to kill human neutrophils after phagocytosis might explain failures in the development of anti-staphylococcal vaccines. Here, we discuss recent progress made in our understanding of the biochemical and genetic properties of PSMs and their role in S. aureus pathogenesis, and suggest potential avenues to target PSMs for the development of anti-staphylococcal drugs.
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46
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Ferreira MT, Manso AS, Gaspar P, Pinho MG, Neves AR. Effect of oxygen on glucose metabolism: utilization of lactate in Staphylococcus aureus as revealed by in vivo NMR studies. PLoS One 2013; 8:e58277. [PMID: 23472168 PMCID: PMC3589339 DOI: 10.1371/journal.pone.0058277] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 02/01/2013] [Indexed: 01/25/2023] Open
Abstract
The ability to successfully adapt to changing host conditions is crucial for full virulence of bacterial pathogens. Staphylococcus aureus has to cope with fluctuating oxygen concentrations during the course of infection. Hence, we studied the effect of oxygen on glucose metabolism in non-growing S. aureus COL-S cells by in vivo13C-NMR. Glucose catabolism was probed at different oxygen concentrations in suspensions of cells grown aerobically (direct effects on metabolism) or anaerobically (transcriptional adjustment to oxygen deprivation). In aerobically-grown cells, the rate of glucose consumption diminished progressively with decreasing oxygen concentrations. Additionally, oxygen deprivation resulted in biphasic glucose consumption, with the second phase presenting a higher rate. The fructose-1,6-bisphosphate pool peaked while glucose was still abundant, but the transient maximum varied with the oxygen concentration. As oxygen became limiting mannitol/mannitol-1-phosphate were detected as products of glucose catabolism. Under anoxic conditions, accumulation of mannitol-1-phosphate ceased with the switch to higher glucose consumption rates, which implies the activation of a more efficient means by which NAD+ can be regenerated. The distribution of end-products deriving from glucose catabolism was dramatically affected by oxygen: acetate increased and lactate decreased with the oxygen concentration; ethanol was formed only anaerobically. Moreover, oxygen promoted the energetically favourable conversion of lactate into acetate, which was particularly noticeable under fully oxygenated conditions. Interestingly, under aerobiosis growing S. aureus cells also converted lactate to acetate, used simultaneously glucose and lactate as substrates for growth, and grew considerably well on lactate-medium. We propose that the efficient lactate catabolism may endow S. aureus with a metabolic advantage in its ecological niche.
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Affiliation(s)
- Maria Teresa Ferreira
- Laboratory of Lactic Acid Bacteria & in vivo NMR, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ana S. Manso
- Laboratory of Lactic Acid Bacteria & in vivo NMR, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Paula Gaspar
- Laboratory of Lactic Acid Bacteria & in vivo NMR, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Mariana G. Pinho
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ana Rute Neves
- Laboratory of Lactic Acid Bacteria & in vivo NMR, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- * E-mail:
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47
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Schreiner J, Kretschmer D, Klenk J, Otto M, Bühring HJ, Stevanovic S, Wang JM, Beer-Hammer S, Peschel A, Autenrieth SE. Staphylococcus aureus phenol-soluble modulin peptides modulate dendritic cell functions and increase in vitro priming of regulatory T cells. THE JOURNAL OF IMMUNOLOGY 2013; 190:3417-26. [PMID: 23460735 DOI: 10.4049/jimmunol.1202563] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The major human pathogen Staphylococcus aureus has very efficient strategies to subvert the human immune system. Virulence of the emerging community-associated methicillin-resistant S. aureus depends on phenol-soluble modulin (PSM) peptide toxins, which are known to attract and lyse neutrophils. However, their influences on other immune cells remain elusive. In this study, we analyzed the impact of PSMs on dendritic cells (DCs) playing an essential role in linking innate and adaptive immunity. In human neutrophils, PSMs exert their function by binding to the formyl peptide receptor (FPR) 2. We show that mouse DCs express the FPR2 homolog mFPR2 as well as its paralog mFPR1 and that PSMs are chemoattractants for DCs at noncytotoxic concentrations. PSMs reduced clathrin-mediated endocytosis and inhibited TLR2 ligand-induced secretion of the proinflammatory cytokines TNF, IL-12, and IL-6, while inducing IL-10 secretion by DCs. As a consequence, treatment with PSMs impaired the capacity of DCs to induce activation and proliferation of CD4(+) T cells, characterized by reduced Th1 but increased frequency of FOXP3(+) regulatory T cells. These regulatory T cells secreted high amounts of IL-10, and their suppression capacity was dependent on IL-10 and TGF-β. Interestingly, the induction of tolerogenic DCs by PSMs appeared to be independent of mFPRs, as shown by experiments with mice lacking mFPR2 (mFPR2(-/-)) and the cognate G protein (p110γ(-/-)). Thus, PSMs from highly virulent pathogens affect DC functions, thereby modulating the adaptive immune response and probably increasing the tolerance toward the pathogen.
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Affiliation(s)
- Jens Schreiner
- Interfaculty Institute for Cell Biology, Eberhard Karls University, 72076 Tübingen, Germany
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48
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Arnison PG, Bibb MJ, Bierbaum G, Bowers AA, Bugni TS, Bulaj G, Camarero JA, Campopiano DJ, Challis GL, Clardy J, Cotter PD, Craik DJ, Dawson M, Dittmann E, Donadio S, Dorrestein PC, Entian KD, Fischbach MA, Garavelli JS, Göransson U, Gruber CW, Haft DH, Hemscheidt TK, Hertweck C, Hill C, Horswill AR, Jaspars M, Kelly WL, Klinman JP, Kuipers OP, Link AJ, Liu W, Marahiel MA, Mitchell DA, Moll GN, Moore BS, Müller R, Nair SK, Nes IF, Norris GE, Olivera BM, Onaka H, Patchett ML, Piel J, Reaney MJT, Rebuffat S, Ross RP, Sahl HG, Schmidt EW, Selsted ME, Severinov K, Shen B, Sivonen K, Smith L, Stein T, Süssmuth RD, Tagg JR, Tang GL, Truman AW, Vederas JC, Walsh CT, Walton JD, Wenzel SC, Willey JM, van der Donk WA. Ribosomally synthesized and post-translationally modified peptide natural products: overview and recommendations for a universal nomenclature. Nat Prod Rep 2013; 30:108-60. [PMID: 23165928 DOI: 10.1039/c2np20085f] [Citation(s) in RCA: 1445] [Impact Index Per Article: 131.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This review presents recommended nomenclature for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), a rapidly growing class of natural products. The current knowledge regarding the biosynthesis of the >20 distinct compound classes is also reviewed, and commonalities are discussed.
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Affiliation(s)
- Paul G Arnison
- Prairie Plant Systems Inc, Botanical Alternatives Inc, Suite 176, 8B-3110 8th Street E, Saskatoon, SK, S7H 0W2, Canada
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Prasad UV, Vasu D, Kumar YN, Kumar PS, Yeswanth S, Swarupa V, Phaneendra BV, Chaudhary A, Sarma PVGK. Cloning, expression and characterization of NADP-dependent isocitrate dehydrogenase from Staphylococcus aureus. Appl Biochem Biotechnol 2013; 169:862-9. [PMID: 23288593 DOI: 10.1007/s12010-012-0027-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 12/10/2012] [Indexed: 12/01/2022]
Abstract
The Krebs cycle dictates oxidative and reductive conditions in Staphylococcus aureus and is mainly regulated by isocitrate dehydrogenase (IDH) which plays pivotal role in the growth and pathogenesis of the bacteria. In the present study, IDH gene from S. aureus ATCC12600 was cloned in the Sma I site of pQE 30 vector; the resultant clone was named as UVIDH1. The insert in the clone was sequenced (accession number HM067707), and the sequence showed complete homology with IDH sequence of other S. aureus strains reported in the database indicating presence of single enzyme in S. aureus, and considerable sequence homology with other bacteria was observed; however, only 24% homology was found with NADP-dependent human IDH. Phylogenetically, the S. aureus IDH showed close identity with Bacillus subtilis and high degree of variability with other bacteria and human IDH. The expression of IDH in the clone UVIDH1 was induced with 1 mM IPTG, and the recombinant IDH was purified by passing through nickel metal chelate column; the purified recombinant IDH showed a single band in SDS-PAGE with a molecular weight of 40 kDa; K(m) and V(max) for isocitrate are 8.2 ± 0.28 and 525 ± 25 μM NADPH/mg/min, respectively, and for cofactor NADP 67.5 ± 2.82 μM and V(max) 50.5 ± 2.12 μM NADPH/mg/min.
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Affiliation(s)
- U Venkateswara Prasad
- Department of Biotechnology, Sri Venkateswara Institute of Medical Sciences, Tirupati 517507, India
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50
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Distinct roles of phenol-soluble modulins in spreading of Staphylococcus aureus on wet surfaces. Appl Environ Microbiol 2012. [PMID: 23183971 DOI: 10.1128/aem.03157-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The human pathogen Staphylococcus aureus is renowned for the rapid colonization of contaminated wounds, medical implants, and food products. Nevertheless, little is known about the mechanisms that allow S. aureus to colonize the respective wet surfaces. The present studies were therefore aimed at identifying factors used by S. aureus cells to spread over wet surfaces, starting either from planktonic or biofilm-associated states. Through proteomics analyses we pinpoint phenol-soluble modulins (PSMs) as prime facilitators of the spreading process. To dissect the roles of the eight PSMs produced by S. aureus, these peptides were chemically synthesized and tested in spreading assays with different psm mutant strains. The results show that PSMα3 and PSMγ are the strongest facilitators of spreading both for planktonic cells and cells in catheter-associated biofilms. Compared to the six other PSMs of S. aureus, PSMα3 and PSMγ combine strong surfactant activities with a relatively low overall hydropathicity. Importantly, we show that PSM-mediated motility of S. aureus facilitates the rapid colonization of wet surfaces next to catheters and the colonization of fresh meat.
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