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Wu X, Wang H, Xiong J, Yang GX, Hu JF, Zhu Q, Chen Z. Staphylococcus aureus biofilm: Formulation, regulatory, and emerging natural products-derived therapeutics. Biofilm 2024; 7:100175. [PMID: 38298832 PMCID: PMC10827693 DOI: 10.1016/j.bioflm.2023.100175] [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: 08/27/2023] [Revised: 12/21/2023] [Accepted: 12/30/2023] [Indexed: 02/02/2024] Open
Abstract
Staphylococcus aureus can readily form biofilm which enhances the drug-resistance, resulting in life-threatening infections involving different organs. Biofilm formation occurs due to a series of developmental events including bacterial adhesion, aggregation, biofilm maturation, and dispersion, which are controlled by multiple regulatory systems. Rapidly increasing research and development outcomes on natural products targeting S. aureus biofilm formation and/or regulation led to an emergent application of active phytochemicals and combinations. This review aimed at providing an in-depth understanding of biofilm formation and regulation mechanisms for S. aureus, outlining the most important antibiofilm strategies and potential targets of natural products, and summarizing the latest progress in combating S. aureus biofilm with plant-derived natural products. These findings provided further evidence for novel antibiofilm drugs research and clinical therapies.
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Affiliation(s)
- Xiying Wu
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, 200443, China
- Institute of Natural Medicine and Health Products, School of Pharmaceutical Sciences, Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Zhejiang, 318000, China
- Department of Natural Medicine, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Huan Wang
- School of Pharmacy, Naval Medical University, Shanghai, 200433, China
| | - Juan Xiong
- Department of Natural Medicine, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Guo-Xun Yang
- Department of Natural Medicine, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Jin-Feng Hu
- Institute of Natural Medicine and Health Products, School of Pharmaceutical Sciences, Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Zhejiang, 318000, China
| | - Quangang Zhu
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, 200443, China
| | - Zhongjian Chen
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, 200443, China
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2
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Vadakkan K, Sathishkumar K, Kuttiyachan Urumbil S, Ponnenkunnathu Govindankutty S, Kumar Ngangbam A, Devi Nongmaithem B. A review of chemical signaling mechanisms underlying quorum sensing and its inhibition in Staphylococcus aureus. Bioorg Chem 2024; 148:107465. [PMID: 38761705 DOI: 10.1016/j.bioorg.2024.107465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/29/2024] [Accepted: 05/14/2024] [Indexed: 05/20/2024]
Abstract
Staphylococcus aureus is a significant bacterium responsible for multiple infections and is a primary cause of fatalities among patients in hospital environments. The advent of pathogenic bacteria such as methicillin-resistant S. aureus revealed the shortcomings of employing antibiotics to treat bacterial infectious diseases. Quorum sensing enhances S. aureus's survivability through signaling processes. Targeting the key components of quorum sensing has drawn much interest nowadays as a promising strategy for combating infections caused by bacteria. Concentrating on the accessory gene regulator quorum-sensing mechanism is the most commonly suggested anti-virulence approach for S.aureus. Quorum quenching is a common strategy for controlling illnesses triggered by microorganisms since it reduces the pathogenicity of bacteria and improves bacterial biofilm susceptibility to antibiotics, thus providing an intriguing prospect for drug discovery. Quorum sensing inhibition reduces selective stresses and constrains the emergence of antibiotic resistance while limiting bacterial pathogenicity. This review examines the quorum sensing mechanisms involved in S. aureus, quorum sensing targets and gene regulation, environmental factors affecting quorum sensing, quorum sensing inhibition, natural products as quorum sensing inhibitory agents and novel therapeutical strategies to target quorum sensing in S. aureus as drug developing technique to augment conventional antibiotic approaches.
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Affiliation(s)
- Kayeen Vadakkan
- Department of Biotechnology, St. Mary's College (Autonomous), Thrissur, Kerala 680020, India; Manipur International University, Imphal, Manipur 795140, India.
| | - Kuppusamy Sathishkumar
- Center for Global Health Research, Saveetha Medical College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Thandalam, Chennai, Tamil Nadu 602105, India
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3
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Li R, Su Z, Sun C, Wu S. Antibacterial insights into alternariol and its derivative alternariol monomethyl ether produced by a marine fungus. Appl Environ Microbiol 2024; 90:e0005824. [PMID: 38470179 PMCID: PMC11022538 DOI: 10.1128/aem.00058-24] [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: 01/11/2024] [Accepted: 02/14/2024] [Indexed: 03/13/2024] Open
Abstract
Alternaria alternata FB1 is a marine fungus identified as a candidate for plastic degradation in our previous study. This fungus has been recently shown to produce secondary metabolites with significant antimicrobial activity against various pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and the notorious aquaculture pathogen Vibrio anguillarum. The antibacterial compounds were purified and identified as alternariol (AOH) and its derivative, alternariol monomethyl ether (AME). We found that AOH and AME primarily inhibited pathogenic bacteria (MRSA or V. anguillarum) by disordering cell division and some other key physiological and biochemical processes. We further demonstrated that AOH could effectively inhibit the unwinding activity of MRSA topoisomerases, which are closely related to cell division and are the potential action target of AOH. The antibacterial activities of AOH and AME were verified by using zebrafish as the in vivo model. Notably, AOH and AME did not significantly affect the viability of normal human liver cells at concentrations that effectively inhibited MRSA or V. anguillarum. Finally, we developed the genetic operation system of A. alternata FB1 and blocked the biosynthesis of AME by knocking out omtI (encoding an O-methyl transferase), which facilitated A. alternata FB1 to only produce AOH. The development of this system in the marine fungus will accelerate the discovery of novel natural products and further bioactivity study.IMPORTANCEMore and more scientific reports indicate that alternariol (AOH) and its derivative alternariol monomethyl ether (AME) exhibit antibacterial activities. However, limited exploration of their detailed antibacterial mechanisms has been performed. In the present study, the antibacterial mechanisms of AOH and AME produced by the marine fungus Alternaria alternata FB1 were disclosed in vitro and in vivo. Given their low toxicity on the normal human liver cell line under the concentrations exhibiting significant antibacterial activity against different pathogens, AOH and AME are proposed to be good candidates for developing promising antibiotics against methicillin-resistant Staphylococcus aureus and Vibrio anguillarum. We also succeeded in blocking the biosynthesis of AME, which facilitated us to easily obtain pure AOH. Moreover, based on our previous results, A. alternata FB1 was shown to enable polyethylene degradation.
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Affiliation(s)
- Rongmei Li
- College of Life Sciences, Qingdao University, Qingdao, China
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Center for Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Zhenjie Su
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Center for Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
- College of Earth Science, University of Chinese Academy of Sciences, Beijing, China
| | - Chaomin Sun
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Center for Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
- College of Earth Science, University of Chinese Academy of Sciences, Beijing, China
| | - Shimei Wu
- College of Life Sciences, Qingdao University, Qingdao, China
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4
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Xu X, Zhou T, Fang X, Hu L, Zhu J, Zheng F. Biological characteristics and pathogenicity of a Staphylococcus aureus strain with an incomplete hemolytic phenotype isolated from bovine milk. Microbiol Immunol 2024; 68:6-14. [PMID: 37985160 DOI: 10.1111/1348-0421.13102] [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: 09/06/2023] [Revised: 10/21/2023] [Accepted: 11/05/2023] [Indexed: 11/22/2023]
Abstract
Staphylococcus aureus is a common pathogen capable of infecting both humans and animals and causing various severe diseases. Here, we aimed to determine the biological features and pathogenicity of S. aureus strain Sa9, of the incomplete hemolysis phenotype, isolated from bovine milk. Sa9 was classified as ST97 by multilocus sequence typing, and it showed increased β-hemolysin expression and lower Hla and Hld expression levels compared with that in the S. aureus USA300 strain LAC. RT-PCR and ELISA results showed that the expression levels of inflammatory cytokines were higher in Sa9-induced mouse primary peritoneal macrophages compared with those induced by the LAC strain. However, the Sa9 strain also mediated anti-inflammatory effects by upregulating IL-10 and IFN-β in macrophages, which were not apparently induced by S. aureus culture supernatants. Phagocytosis and whole-blood survival assays were also performed to assess the in vitro survival of bacteria, and the virulence was evaluated in mice. Although the Sa9 strain showed lower ability of intracellular survival in macrophages than LAC, similar multiplication in human whole blood and pathogenicity toward mice were observed. Taken together, we report that the distinctive immune response induced by the S. aureus strain with an incomplete hemolysis phenotype occurs in cattle, and its potential pathogenicity and risk of transmission to humans require attention.
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Affiliation(s)
- Xiuhua Xu
- Department of Microbiology, Huadong Medical Institute of Biotechniques, Nanjing, China
- Department of Clinical Laboratory, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Tingting Zhou
- Department of Microbiology, Huadong Medical Institute of Biotechniques, Nanjing, China
| | - Xueyao Fang
- Key Laboratory of Medicine in Jiangxi Province, Department of Clinical Laboratory Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Longhua Hu
- Key Laboratory of Medicine in Jiangxi Province, Department of Clinical Laboratory Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jin Zhu
- Department of Microbiology, Huadong Medical Institute of Biotechniques, Nanjing, China
| | - Feng Zheng
- Department of Microbiology, Huadong Medical Institute of Biotechniques, Nanjing, China
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5
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Fohmann I, Weinmann A, Schumacher F, Peters S, Prell A, Weigel C, Spiegel S, Kleuser B, Schubert-Unkmeir A. Sphingosine kinase 1/S1P receptor signaling axis is essential for cellular uptake of Neisseria meningitidis in brain endothelial cells. PLoS Pathog 2023; 19:e1011842. [PMID: 38033162 PMCID: PMC10715668 DOI: 10.1371/journal.ppat.1011842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 12/12/2023] [Accepted: 11/18/2023] [Indexed: 12/02/2023] Open
Abstract
Invasion of brain endothelial cells (BECs) is central to the pathogenicity of Neisseria meningitidis infection. Here, we established a key role for the bioactive sphingolipid sphingosine-1-phosphate (S1P) and S1P receptor (S1PR) 2 in the uptake process. Quantitative sphingolipidome analyses of BECs infected with N. meningitidis revealed elevated S1P levels, which could be attributed to enhanced expression of the enzyme sphingosine kinase 1 and its activity. Increased activity was dependent on the interaction of meningococcal type IV pilus with the endothelial receptor CD147. Concurrently, infection led to increased expression of the S1PR2. Blocking S1PR2 signaling impaired epidermal growth factor receptor (EGFR) phosphorylation, which has been shown to be involved in cytoskeletal remodeling and bacterial endocytosis. Strikingly, targeting S1PR1 or S1PR3 also interfered with bacterial uptake. Collectively, our data support a critical role of the SphK/S1P/S1PR axis in the invasion of N. meningitidis into BECs, defining a potential target for adjuvant therapy.
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Affiliation(s)
- Ingo Fohmann
- Institute for Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Alina Weinmann
- Institute for Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Fabian Schumacher
- Institute of Pharmacy, Pharmacology and Toxicology, Freie Universität Berlin, Berlin, Germany
| | - Simon Peters
- Institute for Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Agata Prell
- Institute of Pharmacy, Pharmacology and Toxicology, Freie Universität Berlin, Berlin, Germany
| | - Cynthia Weigel
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Burkhard Kleuser
- Institute of Pharmacy, Pharmacology and Toxicology, Freie Universität Berlin, Berlin, Germany
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Ashaiba A, Arun AB, Prasad KS, Tellis RC. Leptospiral sphingomyelinase Sph2 as a potential biomarker for diagnosis of leptospirosis. J Microbiol Methods 2022; 203:106621. [PMID: 36375539 DOI: 10.1016/j.mimet.2022.106621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022]
Abstract
Leptospirosis is an underestimated infectious tropical disease caused by the spirochetes belonging to the genus Leptospira. Leptospirosis is grossly underdiagnosed due to its myriad symptoms, varying from mild febrile illness to severe haemorrhage. Laboratory tests for leptospirosis is an extremely important and potent way for disease diagnosis, as the clinical manifestations are very similar to other febrile diseases. Currently available diagnostic techniques are time-consuming, require expertise and sophisticated instruments, and cannot identify the disease at an early phase of infection. Early diagnosis of leptospirosis is the need of the hour while considering the severe complications after the infection and the rate of mortality after misdiagnosis. Secretion of Leptospira-specific sphingomyelinases in leptospirosis patient's urine within a few days of the onset of infection is quite common and is a virulence factor present only in pathogenic Leptospira species. Herein, the structural and functional importance of leptospiral sphingomyelinase Sph2 in leptospirosis pathogenesis, as well as the potential of screening urinary Sph2 for diagnosis and the scope for developing a rapid and easily affordable point-of-care test for urinary leptospiral sphingomyelinase Sph2 as an alternative to current diagnostic methods are discussed.
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Affiliation(s)
- A Ashaiba
- Department of Microbiology, Yenepoya Medical College, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India; Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India
| | - A B Arun
- Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India
| | - K Sudhakara Prasad
- Nano Materials Research Laboratory, Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India; Centre for Nutrition Studies, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India.
| | - Rouchelle C Tellis
- Department of Microbiology, Yenepoya Medical College, Yenepoya (Deemed to be University), Deralakatte, Mangalore 575 018, India.
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7
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Rao L, Xu Y, Shen L, Wang X, Zhao H, Wang B, Zhang J, Xiao Y, Guo Y, Sheng Y, Cheng L, Song Z, Yu F. Small-molecule compound SYG-180-2-2 attenuates Staphylococcus aureus virulence by inhibiting hemolysin and staphyloxanthin production. Front Cell Infect Microbiol 2022; 12:1008289. [PMID: 36310881 PMCID: PMC9606476 DOI: 10.3389/fcimb.2022.1008289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 09/27/2022] [Indexed: 11/19/2022] Open
Abstract
Multi-drug resistant Staphylococcus aureus infection is still a serious threat to global health. Therefore, there is an urgent need to develop new antibacterial agents based on virulence factor therapy to overcome drug resistance. Previously, we synthesized SYG-180-2-2 (C21H16N2OSe), an effective small molecule compound against biofilm. The aim of this study was to investigate the anti-virulence efficacy of SYG-180-2-2 against Staphylococcus aureus. MIC results demonstrated no apparent antibacterial activity of the SYG-180-2-2. The growth curve assay showed that SYG-180-2-2 had nonlethal effect on S. aureus. Besides, SYG-180-2-2 strongly inhibited the hemolytic activity and staphyloxanthin synthesis in S. aureus. Inhibition of staphyloxanthin by SYG-180-2-2 enhanced the sensitivity of S. aureus to oxidants and human whole blood. In addition, SYG-180-2-2 significantly decreased the expression of saeR-mediated hemolytic gene hlb and staphyloxanthin-related crtM, crtN and sigB genes by quantitative polymerase chain reaction (qPCR). Meanwhile, the expression of oxidative stress-related genes sodA, sodM and katA also decreased. Galleria Mellonella assay revealed that SYG-180-2-2 was not toxic to larvae. Further, the larvae infection model showed that the virulence of bacteria was significantly reduced after 4 μg/mL SYG-180-2-2 treatment. SYG-180-2-2 also reduced skin abscess formation in mice by reducing bacterial burden and subcutaneous inflammation. In conclusion, SYG-180-2-2 might be a promising agent to attenuate the virulence of S. aureus by targeting genes associated with hemolytic activity and staphyloxanthin synthesis.
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Affiliation(s)
- Lulin Rao
- Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yanlei Xu
- Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Li Shen
- Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Xinyi Wang
- Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Huilin Zhao
- Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Bingjie Wang
- Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Jiao Zhang
- Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yanghua Xiao
- Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yinjuan Guo
- Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yaoguang Sheng
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Lixia Cheng
- Integrated Traditional Chinese and Western Medicine Hospital, Hangzhou, China
| | - Zengqiang Song
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
- *Correspondence: Fangyou Yu, ; Zengqiang Song,
| | - Fangyou Yu
- Department of Clinical Laboratory, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
- *Correspondence: Fangyou Yu, ; Zengqiang Song,
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8
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Zheng Y, Hunt RL, Villaruz AE, Fisher EL, Liu R, Liu Q, Cheung GYC, Li M, Otto M. Commensal Staphylococcus epidermidis contributes to skin barrier homeostasis by generating protective ceramides. Cell Host Microbe 2022; 30:301-313.e9. [PMID: 35123653 PMCID: PMC8917079 DOI: 10.1016/j.chom.2022.01.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 12/07/2021] [Accepted: 01/11/2022] [Indexed: 12/19/2022]
Abstract
Previously either regarded as insignificant or feared as potential sources of infection, the bacteria living on our skin are increasingly recognized for their role in benefitting human health. Skin commensals modulate mucosal immune defenses and directly interfere with pathogens; however, their contribution to the skin's physical integrity is less understood. Here, we show that the abundant skin commensal Staphylococcus epidermidis contributes to skin barrier integrity. S. epidermidis secretes a sphingomyelinase that acquires essential nutrients for the bacteria and assists the host in producing ceramides, the main constituent of the epithelial barrier that averts skin dehydration and aging. In mouse models, S. epidermidis significantly increases skin ceramide levels and prevents water loss of damaged skin in a fashion entirely dependent on its sphingomyelinase. Our findings reveal a symbiotic mechanism that demonstrates an important role of the skin microbiota in the maintenance of the skin's protective barrier.
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Affiliation(s)
- Yue Zheng
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, MD 20814, USA
| | - Rachelle L Hunt
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, MD 20814, USA
| | - Amer E Villaruz
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, MD 20814, USA
| | - Emilie L Fisher
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, MD 20814, USA
| | - Ryan Liu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, MD 20814, USA
| | - Qian Liu
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, MD 20814, USA
| | - Min Li
- Department of Laboratory Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, MD 20814, USA.
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9
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Tran PM, Tang SS, Salgado-Pabón W. Staphylococcus aureus β-Toxin Exerts Anti-angiogenic Effects by Inhibiting Re-endothelialization and Neovessel Formation. Front Microbiol 2022; 13:840236. [PMID: 35185854 PMCID: PMC8851161 DOI: 10.3389/fmicb.2022.840236] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 01/11/2022] [Indexed: 12/25/2022] Open
Abstract
Staphylococcus aureus causes severe, life-threatening infections that often are complicated by severe local and systemic pathologies with non-healing lesions. A classic example is S. aureus infective endocarditis (IE), where the secreted hemolysin β-toxin potentiates the disease via its sphingomyelinase and biofilm ligase activities. Although these activities dysregulate human aortic endothelial cell activation, β-toxin effect on endothelial cell function in wound healing has not been addressed. With the use of the ex vivo rabbit aortic ring model, we provide evidence that β-toxin prevents branching microvessel formation, highlighting its ability to interfere with tissue re-vascularization and vascular repair. We show that β-toxin specifically targets both human aortic endothelial cell proliferation and cell migration and inhibits human umbilical vein endothelial cell rearrangement into capillary-like networks in vitro. Proteome arrays specific for angiogenesis-related molecules provided evidence that β-toxin promotes an inhibitory profile in endothelial cell monolayers, specifically targeting production of TIMP-1, TIMP-4, and IGFBP-3 to counter the effect of a pro-angiogenic environment. Dysregulation in the production of these molecules is known to result in sprouting defects (including deficient cell proliferation, migration, and survival), vessel instability and/or vascular regression. When endothelial cells are grown under re-endothelialization/wound healing conditions, β-toxin decreases the pro-angiogenic molecule MMP-8 and increases the anti-angiogenic molecule endostatin. Altogether, the data indicate that β-toxin is an anti-angiogenic virulence factor and highlight a mechanism where β-toxin exacerbates S. aureus invasive infections by interfering with tissue re-vascularization and vascular repair.
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Affiliation(s)
- Phuong M Tran
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States.,Department of Microbiology and Immunology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Sharon S Tang
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States
| | - Wilmara Salgado-Pabón
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States
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10
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Label-free electrochemical biosensor for determination of procalcitonin based on graphene-wrapped Co nanoparticles encapsulated in carbon nanobrushes coupled with AuPtCu nanodendrites. Mikrochim Acta 2022; 189:110. [PMID: 35178584 DOI: 10.1007/s00604-022-05179-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 01/06/2022] [Indexed: 10/19/2022]
Abstract
A new label-free electrochemical immunosensor was constructed for quantitative detection of procalcitonin (PCT), by employing AuPtCu nanodendrites (AuPtCu NDs, prepared by a one-pot solvothermal method) and graphene-wrapped Co nanoparticles encapsulated in 3D N-doped carbon nanobrushes (G-Co@ NCNBs), obtained by self-catalyzed chemical vapor deposition as immune-sensing platform. Impressively, the home-made nanocomposite enlarged the highly accessible active sites and promoted the mass/electron transport, in turn showing the efficient synergistic catalysis towards H2O2 reduction, combined by greatly increasing the loading capacity of the PCT antibody (Ab). The as-constructed sensor displayed a dynamic linear range of 0.0001 ~ 100 ng mL-1 along with an ultra-low limit of detection (LOD = 0.011 pg mL-1, S/N = 3) and was further explored for determination of PCT in a diluted serum sample with acceptable results. The sensor provides some valuable guidelines for bioassay and early diagnosis of sepsis.
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11
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Group B Streptococcus CAMP Factor Does Not Contribute to Interactions with the Vaginal Epithelium and Is Dispensable for Vaginal Colonization in Mice. Microbiol Spectr 2021; 9:e0105821. [PMID: 34908468 PMCID: PMC8672899 DOI: 10.1128/spectrum.01058-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Gram-positive pathogen group B Streptococcus (GBS) is a leading cause of neonatal bacterial infections, preterm birth, and stillbirth. Although maternal GBS vaginal colonization is a risk factor for GBS-associated adverse birth outcomes, mechanisms promoting GBS vaginal persistence are not fully defined. GBS possesses a broadly conserved small molecule, CAMP factor, that is co-hemolytic in the presence of Staphylococcus aureus sphingomyelinase C. While this co-hemolytic reaction is commonly used by clinical laboratories to identify GBS, the contribution of CAMP factor to GBS vaginal persistence is unknown. Using in vitro biofilm, adherence and invasion assays with immortalized human vaginal epithelial VK2 cells, and a mouse model of GBS vaginal colonization, we tested the contribution of CAMP factor using GBS strain COH1 and its isogenic CAMP-deficient mutant (Δcfb). We found no evidence for CAMP factor involvement in GBS biofilm formation, or adherence, invasion, or cytotoxicity toward VK2 cells in the presence or absence of S. aureus. Additionally, there was no difference in vaginal burdens or persistence between COH1 and Δcfb strains in a murine colonization model. In summary, our results using in vitro human cell lines and murine models do not support a critical role for CAMP factor in promoting GBS vaginal colonization. IMPORTANCE Group B Streptococcus (GBS) remains a pervasive pathogen for pregnant women and their newborns. Maternal screening and intrapartum antibiotic prophylaxis to GBS-positive mothers have reduced, but not eliminated GBS neonatal disease, and have not impacted GBS-associated preterm birth or stillbirth. Additionally, this antibiotic exposure is associated with adverse effects on the maternal and neonatal microbiota. Identifying key GBS factors important for maternal vaginal colonization will foster development of more targeted, alternative therapies to antibiotic treatment. Here, we investigate the contribution of a broadly conserved GBS determinant, CAMP factor, to GBS vaginal colonization and find that CAMP factor is unlikely to be a biological target to control maternal GBS colonization.
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Lerche CJ, Schwartz F, Theut M, Fosbøl EL, Iversen K, Bundgaard H, Høiby N, Moser C. Anti-biofilm Approach in Infective Endocarditis Exposes New Treatment Strategies for Improved Outcome. Front Cell Dev Biol 2021; 9:643335. [PMID: 34222225 PMCID: PMC8249808 DOI: 10.3389/fcell.2021.643335] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 05/04/2021] [Indexed: 12/13/2022] Open
Abstract
Infective endocarditis (IE) is a life-threatening infective disease with increasing incidence worldwide. From early on, in the antibiotic era, it was recognized that high-dose and long-term antibiotic therapy was correlated to improved outcome. In addition, for several of the common microbial IE etiologies, the use of combination antibiotic therapy further improves outcome. IE vegetations on affected heart valves from patients and experimental animal models resemble biofilm infections. Besides the recalcitrant nature of IE, the microorganisms often present in an aggregated form, and gradients of bacterial activity in the vegetations can be observed. Even after appropriate antibiotic therapy, such microbial formations can often be identified in surgically removed, infected heart valves. Therefore, persistent or recurrent cases of IE, after apparent initial infection control, can be related to biofilm formation in the heart valve vegetations. On this background, the present review will describe potentially novel non-antibiotic, antimicrobial approaches in IE, with special focus on anti-thrombotic strategies and hyperbaric oxygen therapy targeting the biofilm formation of the infected heart valves caused by Staphylococcus aureus. The format is translational from preclinical models to actual clinical treatment strategies.
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Affiliation(s)
- Christian Johann Lerche
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Franziska Schwartz
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Marie Theut
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Emil Loldrup Fosbøl
- Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Kasper Iversen
- Department of Cardiology, Herlev and Gentofte Hospital, University of Copenhagen, Herlev, Denmark.,Department of Emergency Medicine, Herlev and Gentofte Hospital, University of Copenhagen, Herlev, Denmark
| | - Henning Bundgaard
- Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Claus Moser
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
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13
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Rohmer C, Wolz C. The Role of hlb-Converting Bacteriophages in Staphylococcus aureus Host Adaption. Microb Physiol 2021; 31:109-122. [PMID: 34126612 DOI: 10.1159/000516645] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/17/2021] [Indexed: 11/19/2022]
Abstract
As an opportunistic pathogen of humans and animals, Staphylococcus aureus asymptomatically colonizes the nasal cavity but is also a leading cause of life-threatening acute and chronic infections. The evolution of S. aureus resulting from short- and long-term adaptation to diverse hosts is tightly associated with mobile genetic elements. S. aureus strains can carry up to four temperate phages, many of which possess accessory genes encoding staphylococcal virulence factors. More than 90% of human nasal isolates of S. aureus have been shown to carry Sa3int phages, whereas invasive S. aureus isolates tend to lose these phages. Sa3int phages integrate as prophages into the bacterial hlb gene, disrupting the expression of the sphingomyelinase Hlb, an important virulence factor under specific infection conditions. Virulence factors encoded by genes carried by Sa3int phages include staphylokinase, enterotoxins, chemotaxis-inhibitory protein, and staphylococcal complement inhibitor, all of which are highly human specific and probably essential for bacterial survival in the human host. The transmission of S. aureus from humans to animals is strongly correlated with the loss of Sa3int phages, whereas phages are regained once a strain is transmitted from animals to humans. Thus, both the insertion and excision of prophages may confer a fitness advantage to this bacterium. There is also growing evidence that Sa3int phages may perform "active lysogeny," a process during which prophages are temporally excised from the chromosome without forming intact phage particles. The molecular mechanisms controlling the peculiar life cycle of Sa3int phages remain largely unclear. Nevertheless, their regulation is likely fine-tuned to ensure bacterial survival within different hosts.
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Affiliation(s)
- Carina Rohmer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Christiane Wolz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany.,Cluster of Excellence EXC 2124 "Controlling Microbes to Fight Infections", Tübingen, Germany
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14
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Guan Z, Liu Y, Liu C, Wang H, Feng J, Yang G. Staphylococcus aureus β-Hemolysin Up-Regulates the Expression of IFN-γ by Human CD56 bright NK Cells. Front Cell Infect Microbiol 2021; 11:658141. [PMID: 33854984 PMCID: PMC8039520 DOI: 10.3389/fcimb.2021.658141] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/11/2021] [Indexed: 01/12/2023] Open
Abstract
IFN-γ is produced upon stimulation with S. aureus and may play a detrimental role during infection. However, whether hemolysins play a role in the mechanism of IFN-γ production has not been fully characterized. In this study, we demonstrated that Hlb, one of the major hemolysins of S. aureus, upregulated IFN-γ production by CD56bright NK cells from human peripheral blood mononuclear cells (PBMCs). Further investigation showed that Hlb increased calcium influx and induced phosphorylation of ERK1/2. Either blocking calcium or specifically inhibiting phosphorylation of ERK1/2 decreased the production of IFN-γ induced by Hlb. Moreover, we found that this process was dependent on the sphingomyelinase activity of Hlb. Our findings revealed a novel mechanism of IFN-γ production in NK cells induced by Hlb, which may be involved in the pathogenesis of S. aureus.
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Affiliation(s)
- Zhangchun Guan
- Beijing Institute of Pharmacology and Toxicology, Beijing, China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, China
| | - Yu Liu
- Beijing Institute of Pharmacology and Toxicology, Beijing, China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, China
| | - Chenghua Liu
- Beijing Institute of Pharmacology and Toxicology, Beijing, China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, China
| | - Huiting Wang
- Beijing Institute of Pharmacology and Toxicology, Beijing, China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, China
| | - Jiannan Feng
- Beijing Institute of Pharmacology and Toxicology, Beijing, China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, China
| | - Guang Yang
- Beijing Institute of Pharmacology and Toxicology, Beijing, China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, China
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15
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Lisowska-Łysiak K, Lauterbach R, Międzobrodzki J, Kosecka-Strojek M. Epidemiology and Pathogenesis of Staphylococcus Bloodstream Infections in Humans: a Review. Pol J Microbiol 2021; 70:13-23. [PMID: 33815523 PMCID: PMC8330453 DOI: 10.33073/pjm-2021-005] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/18/2021] [Accepted: 01/12/2021] [Indexed: 01/19/2023] Open
Abstract
Staphylococci are among the most frequent human microbiota components associated with the high level of bloodstream infection (BSI) episodes. In predisposed patients, there is a high risk of transformation of BSI episodes to sepsis. Both bacterial and host factors are crucial for the outcomes of BSI and sepsis. The highest rates of BSI episodes were reported in Africa, where these infections were up to twice as high as the European rates. However, there remains a great need to analyze African data for comprehensive quantification of staphylococcal BSI prevalence. The lowest rates of BSI exist in Australia. Asian, European, and North American data showed similar frequency values. Worldwide analysis indicated that both Staphylococcus aureus and coagulase-negative staphylococci (CoNS) are the most frequent BSI agents. In the second group, the most prevalent species was Staphylococcus epidermidis, although CoNS were not identified at the species level in many studies. The lack of a significant worldwide decrease in BSI episodes indicates a great need to implement standardized diagnostic methods and research etiological factors using advanced genetic methods.
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Affiliation(s)
- Klaudia Lisowska-Łysiak
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Ryszard Lauterbach
- Department of Neonatology, Collegium Medicum, Jagiellonian University, Kraków, Poland
| | - Jacek Międzobrodzki
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Maja Kosecka-Strojek
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
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16
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Ziegler AC, Müller T, Gräler MH. Sphingosine 1-phosphate in sepsis and beyond: Its role in disease tolerance and host defense and the impact of carrier molecules. Cell Signal 2020; 78:109849. [PMID: 33249088 DOI: 10.1016/j.cellsig.2020.109849] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/19/2020] [Accepted: 11/20/2020] [Indexed: 12/29/2022]
Abstract
Sphingosine 1-phosphate (S1P) is an important immune modulator responsible for physiological cellular responses like lymphocyte development and function, positioning and emigration of T and B cells and cytokine secretion. Recent reports indicate that S1P does not only regulate immunity, but can also protect the function of organs by inducing disease tolerance. S1P also influences the replication of certain pathogens, and sphingolipids are also involved in pathogen recognition and killing. Certain carrier molecules for S1P like serum albumin and high density lipoproteins contribute to the regulation of S1P effects. They are able to associate with S1P and modulate its signaling properties. Similar to S1P, both carrier molecules are also decreased in sepsis patients and likely contribute to sepsis pathology and severity. In this review, we will introduce the concept of disease tolerance and the involvement of S1P. We will also discuss the contribution of S1P and its precursor sphingosine to host defense mechanisms against pathogens. Finally, we will summarize current data demonstrating the influence of carrier molecules for differential S1P signaling. The presented data may lead to new strategies for the prevention and containment of sepsis.
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Affiliation(s)
- Anke C Ziegler
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, 07740 Jena, Germany; Center for Molecular Biomedicine, Jena University Hospital, 07745 Jena, Germany
| | - Tina Müller
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, 07740 Jena, Germany; Center for Molecular Biomedicine, Jena University Hospital, 07745 Jena, Germany
| | - Markus H Gräler
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, 07740 Jena, Germany; Center for Molecular Biomedicine, Jena University Hospital, 07745 Jena, Germany; Center for Sepsis Control and Care, Jena University Hospital, 07740 Jena, Germany.
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17
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Vlaeminck J, Raafat D, Surmann K, Timbermont L, Normann N, Sellman B, van Wamel WJB, Malhotra-Kumar S. Exploring Virulence Factors and Alternative Therapies against Staphylococcus aureus Pneumonia. Toxins (Basel) 2020; 12:toxins12110721. [PMID: 33218049 PMCID: PMC7698915 DOI: 10.3390/toxins12110721] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/12/2020] [Accepted: 11/15/2020] [Indexed: 12/13/2022] Open
Abstract
Pneumonia is an acute pulmonary infection associated with high mortality and an immense financial burden on healthcare systems. Staphylococcus aureus is an opportunistic pathogen capable of inducing S. aureus pneumonia (SAP), with some lineages also showing multidrug resistance. Given the high level of antibiotic resistance, much research has been focused on targeting S. aureus virulence factors, including toxins and biofilm-associated proteins, in an attempt to develop effective SAP therapeutics. Despite several promising leads, many hurdles still remain for S. aureus vaccine research. Here, we review the state-of-the-art SAP therapeutics, highlight their pitfalls, and discuss alternative approaches of potential significance and future perspectives.
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Affiliation(s)
- Jelle Vlaeminck
- Laboratory of Medical Microbiology, Vaccine and Infectious Diseases Institute, University of Antwerp, 2610 Antwerp, Belgium; (J.V.); (L.T.)
| | - Dina Raafat
- Department of Immunology, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, 17475 Greifswald, Germany; (D.R.); (N.N.)
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt
| | - Kristin Surmann
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, 17475 Greifswald, Germany;
| | - Leen Timbermont
- Laboratory of Medical Microbiology, Vaccine and Infectious Diseases Institute, University of Antwerp, 2610 Antwerp, Belgium; (J.V.); (L.T.)
| | - Nicole Normann
- Department of Immunology, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, 17475 Greifswald, Germany; (D.R.); (N.N.)
| | - Bret Sellman
- Microbiome Discovery, Microbial Sciences, BioPharmaceuticals R & D, AstraZeneca, Gaithersburg, MD 20878, USA;
| | - Willem J. B. van Wamel
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center Rotterdam, 3015 Rotterdam, The Netherlands;
| | - Surbhi Malhotra-Kumar
- Laboratory of Medical Microbiology, Vaccine and Infectious Diseases Institute, University of Antwerp, 2610 Antwerp, Belgium; (J.V.); (L.T.)
- Correspondence: ; Tel.: +32-3-265-27-52
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18
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Phylogenetic and Molecular Profile of Staphylococcus aureus Isolated from Bloodstream Infections in Northeast Brazil. Microorganisms 2019; 7:microorganisms7070210. [PMID: 31336623 PMCID: PMC6680844 DOI: 10.3390/microorganisms7070210] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 12/16/2022] Open
Abstract
Staphylococcus aureus is a notorious human pathogen associated with serious nosocomial and community-acquired infections, such as pneumonia, meningitis, endocarditis, toxic shock syndrome, and sepsis, among others. The objective of this study was to investigate the molecular profile, antimicrobial resistance, and clonal diversity of S. aureus isolated from the bloodstream. The determination of the minimum inhibitory concentration (MIC) of the antimicrobial was performed by an automated method. The presence of several virulence and resistance genes was evaluated by PCR. In addition, multilocus sequence typing (MLST) was used to analyze the clonal diversity of S. aureus. A high resistance to oxacillin (78%), clindamycin (78%), erythromycin (70%), ciprofloxacin (61%), and gentamicin (52%) was observed among the isolates. In most of them, the following virulence genes were detected: hlb (83%), ebpS (61%), icaA (57%), fnbpA (17%), and clfA (13%). Only one isolate carried the pvl gene. MLST analysis identified five new sequence types (STs): 5429, 5430, 5431, 5432, and 5433, as well as another seven-ST5, ST97, ST398, ST101, ST30, ST461, and ST2779-among the remaining strains. These seven STs and the four new STs are clustered in four clonal complexes: CC1, CC2, CC7, and CC17. Phylogenetic analysis showed the genetic relationship of the five new ST strains with another 18 strains. Altogether, these analyses indicate the horizontal transfer acquisition of virulence factor genes and multidrug resistance.
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19
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ϕSa3mw Prophage as a Molecular Regulatory Switch of Staphylococcus aureus β-Toxin Production. J Bacteriol 2019; 201:JB.00766-18. [PMID: 30962356 PMCID: PMC6597384 DOI: 10.1128/jb.00766-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/01/2019] [Indexed: 11/20/2022] Open
Abstract
Phage regulatory switches (phage-RSs) are a newly described form of active lysogeny where prophages function as regulatory mechanisms for expression of chromosomal bacterial genes. In Staphylococcus aureus, ϕSa3int is a widely distributed family of prophages that integrate into the β-toxin structural gene hlb, effectively inactivating it. However, β-toxin-producing strains often arise during infections and are more virulent in experimental infective endocarditis and pneumonia infections. We present evidence that in S. aureus MW2, ϕSa3mw excision is temporally and differentially responsive to growth conditions relevant to S. aureus pathogenesis. PCR analyses of ϕSa3mw (integrated and excised) and of intact hlb showed that ϕSa3mw preferentially excises in response to hydrogen peroxide-induced oxidative stress and during biofilm growth. ϕSa3mw remains as a prophage when in contact with human aortic endothelial cells in culture. A criterion for a prophage to be considered a phage-RS is the inability to lyse host cells. MW2 grown under phage-inducing conditions did not release infectious phage particles by plaque assay or transmission electron microscopy, indicating that ϕSa3mw does not carry out a productive lytic cycle. These studies highlight a dynamic, and perhaps more sophisticated, S. aureus-prophage interaction where ϕSa3int prophages provide a novel regulatory mechanism for the conditional expression of virulence factors.IMPORTANCE β-Toxin is a sphingomyelinase hemolysin that significantly contributes to Staphylococcus aureus pathogenesis. In most S. aureus isolates the prophage ϕSa3int inserts into the β-toxin gene hlb, inactivating it, but human and experimental infections give rise to β-toxin-producing variants. However, it remained to be established whether ϕSa3mw excises in response to specific environmental cues, restoring the β-toxin gene sequence. This is not only of fundamental interest but also critical when designing intervention strategies and therapeutics. We provide evidence that ϕSa3mw actively excises, allowing the conditional expression of β-toxin. ϕSa3int prophages may play a novel and largely uncharacterized role in S. aureus pathogenesis as molecular regulatory switches that promote bacterial fitness and adaptation to the challenges presented by the mammalian host.
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20
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Belfort M, Lambowitz AM. Group II Intron RNPs and Reverse Transcriptases: From Retroelements to Research Tools. Cold Spring Harb Perspect Biol 2019; 11:11/4/a032375. [PMID: 30936187 DOI: 10.1101/cshperspect.a032375] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Group II introns, self-splicing retrotransposons, serve as both targets of investigation into their structure, splicing, and retromobility and a source of tools for genome editing and RNA analysis. Here, we describe the first cryo-electron microscopy (cryo-EM) structure determination, at 3.8-4.5 Å, of a group II intron ribozyme complexed with its encoded protein, containing a reverse transcriptase (RT), required for RNA splicing and retromobility. We also describe a method called RIG-seq using a retrotransposon indicator gene for high-throughput integration profiling of group II introns and other retrotransposons. Targetrons, RNA-guided gene targeting agents widely used for bacterial genome engineering, are described next. Finally, we detail thermostable group II intron RTs, which synthesize cDNAs with high accuracy and processivity, for use in various RNA-seq applications and relate their properties to a 3.0-Å crystal structure of the protein poised for reverse transcription. Biological insights from these group II intron revelations are discussed.
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Affiliation(s)
- Marlene Belfort
- Department of Biological Sciences and RNA Institute, University at Albany, State University of New York, Albany, New York 12222
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712
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21
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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: 181] [Impact Index Per Article: 36.2] [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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22
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Che R, Ding S, Zhang Q, Yang W, Yan J, Lin X. Haemolysin Sph2 of Leptospira interrogans induces cell apoptosis via intracellular reactive oxygen species elevation and mitochondrial membrane injury. Cell Microbiol 2018; 21:e12959. [PMID: 30278102 DOI: 10.1111/cmi.12959] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 09/18/2018] [Accepted: 09/19/2018] [Indexed: 12/13/2022]
Abstract
Leptospira interrogans causes widespread leptospirosis in humans and animals, with major symptoms of jaundice and haemorrhage. Sph2, a member of the sphingomyelinase haemolysins, is an important virulence factor for leptospire. In this study, the function and mechanism of Sph2 in the pathogenesis of leptospirosis were investigated to further understand the pathogenesis of leptospire. Real-time PCR analysis of expression levels during cell invasion showed that sph2 gene expression was transiently induced in human umbilical vein endothelial cells (HUVECs), human embryo liver cells (L02), and human epithelial lung cells (L132), with expression levels reaching a peak after 45 min of infection. Further functional analysis of recombinant Sph2 (rSph2) by LDH assays and confocal microscopy showed that rSph2 can be internalised by cells both by causing cell membrane damage and by a damage-independent clathrin-mediated endocytosis pathway. Subsequently, rSph2 is able to translocate to mitochondria, which led to an increase in the levels of reactive oxygen species (ROS) and a decrease of the mitochondrial membrane potential (ΔΨm ). Further flowcytometry analyses after rSph2 exposure showed that 28.7%, 31%, and 27.3% of the HUVEC, L02, and L132 cells, respectively, became apoptotic. Because apoptosis could be decreased with the ROS inhibitor N-acetyl cysteine, these experiments suggested that rSph2 triggers apoptosis through mitochondrial membrane damage and ROS elevation. The ability of leptospiral haemolysin rSph2 to cause apoptosis likely contributes to the pathogenesis of leptospirosis.
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Affiliation(s)
- Rongbo Che
- Department of Medical Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Shibiao Ding
- Department of Medical Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China.,Department of Clinical Laboratory, Hospital of integrated traditional Chinese and Western, Hangzhou, China
| | - Qinchao Zhang
- Department of Medical Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Weiqun Yang
- Department of Medical Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jie Yan
- Department of Medical Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China.,Basic Medical Microbiology Division, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xu'ai Lin
- Department of Medical Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China.,Basic Medical Microbiology Division, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
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23
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Stauffer BB, Cui G, Cottrill KA, Infield DT, McCarty NA. Bacterial Sphingomyelinase is a State-Dependent Inhibitor of the Cystic Fibrosis Transmembrane conductance Regulator (CFTR). Sci Rep 2017; 7:2931. [PMID: 28592822 PMCID: PMC5462758 DOI: 10.1038/s41598-017-03103-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 04/24/2017] [Indexed: 02/07/2023] Open
Abstract
Sphingomyelinase C (SMase) inhibits CFTR chloride channel activity in multiple cell systems, an effect that could exacerbate disease in CF and COPD patients. The mechanism by which sphingomyelin catalysis inhibits CFTR is not known but evidence suggests that it occurs independently of CFTR's regulatory "R" domain. In this study we utilized the Xenopus oocyte expression system to shed light on how CFTR channel activity is reduced by SMase. We found that the pathway leading to inhibition is not membrane delimited and that inhibited CFTR channels remain at the cell membrane, indicative of a novel silencing mechanism. Consistent with an effect on CFTR gating behavior, we found that altering gating kinetics influenced the sensitivity to inhibition by SMase. Specifically, increasing channel activity by introducing the mutation K1250A or pretreating with the CFTR potentiator VX-770 (Ivacaftor) imparted resistance to inhibition. In primary bronchial epithelial cells, we found that basolateral, but not apical, application of SMase leads to a redistribution of sphingomyelin and a reduction in forskolin- and VX-770-stimulated currents. Taken together, these data suggest that SMase inhibits CFTR channel function by locking channels into a closed state and that endogenous CFTR in HBEs is affected by SMase activity.
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Affiliation(s)
- B B Stauffer
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
- Molecular and Systems Pharmacology program, Emory University, 201 Dowman Drive, Atlanta, GA, 20322, USA
| | - G Cui
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
| | - K A Cottrill
- Molecular and Systems Pharmacology program, Emory University, 201 Dowman Drive, Atlanta, GA, 20322, USA
| | - D T Infield
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
| | - N A McCarty
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA.
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Staphylococcal β-Toxin Modulates Human Aortic Endothelial Cell and Platelet Function through Sphingomyelinase and Biofilm Ligase Activities. mBio 2017; 8:mBio.00273-17. [PMID: 28325766 PMCID: PMC5362035 DOI: 10.1128/mbio.00273-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Staphylococcus aureus causes many infections, such as skin and soft tissue, pneumonia, osteomyelitis, and infective endocarditis (IE). IE is an endovascular infection of native and prosthetic valves and the lining of the heart; it is characterized by the formation of cauliflower-like “vegetations” composed of fibrin, platelets, other host factors, bacteria, and bacterial products. β-Toxin is an S. aureus virulence factor that contributes to the microorganism’s ability to cause IE. This cytolysin has two enzymatic activities: sphingomyelinase (SMase) and biofilm ligase. Although both activities have functions in a rabbit model of IE, the mechanism(s) by which β-toxin directly affects human cells and is involved in the infectious process has not been elucidated. Here, we compared the in vitro effects of purified recombinant wild-type β-toxin, SMase-deficient β-toxin (H289N), and biofilm ligase-deficient β-toxin (H162A and/or D163A) on human aortic endothelial cells (HAECs) and platelets. β-Toxin was cytotoxic to HAECs and inhibited the production of interleukin 8 (IL-8) from these cells by both SMase and biofilm ligase activities. β-Toxin altered HAEC surface expression of CD40 and vascular cell adhesion molecule 1 (VCAM-1). HAECs treated with β-toxin displayed granular membrane morphology not seen in treatment with the SMase-deficient mutant. The altered morphology resulted in two possibly separable activities, cell rounding and redistribution of cell membranes into granules, which were not the result of endosome production from the Golgi apparatus or lysosomes. β-Toxin directly aggregated rabbit platelets via SMase activity. Each year there are up to 100,000 cases of infective endocarditis (IE) in the United States. S. aureus is the most common pathogen in patients with health care-associated IE and the leading cause of community-associated IE in the developed world. Multiple clonal group strains as defined by the Centers for Disease Control and Prevention, particularly USA200 and other clones encoding β-toxin, are highly associated with IE. Considering the strong association and established contribution of β-toxin in animal models of IE, determining how β-toxin directly affects human cell types, including endothelial cells and platelets, is important. In this study, we demonstrate that β-toxin functions to modulate endothelial cells and platelets by both toxin sphingomyelinase and biofilm ligase activities. Our data suggest that these activities modulate inflammation and increase infection severity.
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