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Waidner LA, Potdukhe TV. Tools to Enumerate and Predict Distribution Patterns of Environmental Vibrio vulnificus and Vibrio parahaemolyticus. Microorganisms 2023; 11:2502. [PMID: 37894160 PMCID: PMC10609196 DOI: 10.3390/microorganisms11102502] [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: 09/07/2023] [Revised: 09/28/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
Vibrio vulnificus (Vv) and Vibrio parahaemolyticus (Vp) are water- and foodborne bacteria that can cause several distinct human diseases, collectively called vibriosis. The success of oyster aquaculture is negatively impacted by high Vibrio abundances. Myriad environmental factors affect the distribution of pathogenic Vibrio, including temperature, salinity, eutrophication, extreme weather events, and plankton loads, including harmful algal blooms. In this paper, we synthesize the current understanding of ecological drivers of Vv and Vp and provide a summary of various tools used to enumerate Vv and Vp in a variety of environments and environmental samples. We also highlight the limitations and benefits of each of the measurement tools and propose example alternative tools for more specific enumeration of pathogenic Vv and Vp. Improvement of molecular methods can tighten better predictive models that are potentially important for mitigation in more controlled environments such as aquaculture.
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Affiliation(s)
- Lisa A. Waidner
- Hal Marcus College of Science and Engineering, University of West Florida, 11000 University Pkwy, Building 58, Room 108, Pensacola, FL 32514, USA
| | - Trupti V. Potdukhe
- GEMS Program, College of Medicine, University of Illinois Chicago, 1853 W. Polk St., Chicago, IL 60612, USA;
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Vibrio vulnificus PlpA facilitates necrotic host cell death induced by the pore forming MARTX toxin. J Microbiol 2022; 60:224-233. [PMID: 35102528 DOI: 10.1007/s12275-022-1448-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 01/10/2022] [Accepted: 01/10/2022] [Indexed: 10/19/2022]
Abstract
Opportunistic pathogen Vibrio vulnificus causes severe systemic infection in humans with high mortality. Although multiple exotoxins have been characterized in V. vulnificus, their interactions and potential synergistic roles in pathogen-induced host cell death have not been investigated previously. By employing a series of multiple exotoxin deletion mutants, we investigated whether specific exotoxins of the pathogen functioned together to achieve severe and rapid necrotic cell death. Human epithelial cells treated with V. vulnificus with a plpA deletion background exhibited an unusually prolonged cell blebbing, suggesting the importance of PlpA, a phospholipase A2, in rapid necrotic cell death by this pathogen. Additional deletion of the rtxA gene encoding the multifunctional autoprocessing repeats-in-toxin (MARTX) toxin did not result in necrotic cell blebs. However, if the rtxA gene was engineered to produce an effector-free MARTX toxin, the cell blebbing was observed, indicating that the pore forming activity of the MARTX toxin is sufficient, but the MARTX toxin effector domains are not necessary, for the blebbing. When a recombinant PlpA was treated on the blebbed cells, the blebs were completely disrupted. Consistent with this, MARTX toxin-pendent rapid release of cytosolic lactate dehydrogenase was significantly delayed in the plpA deletion background. Mutations in other exotoxins such as elastase, cytolysin/hemolysin, and/or extracellular metalloprotease did not affect the bleb formation or disruption. Together, these findings indicate that the pore forming MARTX toxin and the phospholipase A2, PlpA, cooperate sequentially to achieve rapid necrotic cell death by inducing cell blebbing and disrupting the blebs, respectively.
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Spatiotemporal Regulation of Vibrio Exotoxins by HlyU and Other Transcriptional Regulators. Toxins (Basel) 2020; 12:toxins12090544. [PMID: 32842612 PMCID: PMC7551375 DOI: 10.3390/toxins12090544] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023] Open
Abstract
After invading a host, bacterial pathogens secrete diverse protein toxins to disrupt host defense systems. To ensure successful infection, however, pathogens must precisely regulate the expression of those exotoxins because uncontrolled toxin production squanders energy. Furthermore, inappropriate toxin secretion can trigger host immune responses that are detrimental to the invading pathogens. Therefore, bacterial pathogens use diverse transcriptional regulators to accurately regulate multiple exotoxin genes based on spatiotemporal conditions. This review covers three major exotoxins in pathogenic Vibrio species and their transcriptional regulation systems. When Vibrio encounters a host, genes encoding cytolysin/hemolysin, multifunctional-autoprocessing repeats-in-toxin (MARTX) toxin, and secreted phospholipases are coordinately regulated by the transcriptional regulator HlyU. At the same time, however, they are distinctly controlled by a variety of other transcriptional regulators. How this coordinated but distinct regulation of exotoxins makes Vibrio species successful pathogens? In addition, anti-virulence strategies that target the coordinating master regulator HlyU and related future research directions are discussed.
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Abstract
V. vulnificus is an opportunistic human pathogen that can cause life-threatening sepsis in immunocompromised patients via seafood poisoning or wound infection. Among the toxic substances produced by this pathogen, the MARTX toxin greatly contributes to disease progression by promoting the dysfunction and death of host cells, which allows the bacteria to disseminate and colonize the host. In response to this, host cells mount a counterattack against the invaders by upregulating various defense genes. In this study, the gene expression profiles of both host cells and V. vulnificus were analyzed by RNA sequencing to gain a comprehensive understanding of host-pathogen interactions. Our results suggest that V. vulnificus uses the MARTX toxin to subvert host cell immune responses as well as to oppose host counterattacks such as iron limitation. To understand toxin-stimulated host-pathogen interactions, we performed dual-transcriptome sequencing experiments using human epithelial (HT-29) and differentiated THP-1 (dTHP-1) immune cells infected with the sepsis-causing pathogen Vibrio vulnificus (either the wild-type [WT] pathogen or a multifunctional-autoprocessing repeats-in-toxin [MARTX] toxin-deficient strain). Gene set enrichment analyses revealed MARTX toxin-dependent responses, including negative regulation of extracellular related kinase 1 (ERK1) and ERK2 (ERK1/2) signaling and cell cycle regulation in HT-29 and dTHP-1 cells, respectively. Further analysis of the expression of immune-related genes suggested that the MARTX toxin dampens immune responses in gut epithelial cells but accelerates inflammation and nuclear factor κB (NF-κB) signaling in immune cells. With respect to the pathogen, siderophore biosynthesis genes were significantly more highly expressed in WT V. vulnificus than in the MARTX toxin-deficient mutant upon infection of dTHP-1 cells. Consistent with these results, iron homeostasis genes that limit iron levels for invading pathogens were overexpressed in WT V. vulnificus-infected dTHP-1 cells. Taken together, these results suggest that MARTX toxin regulates host inflammatory responses during V. vulnificus infection while also countering host defense mechanisms such as iron limitation. IMPORTANCEV. vulnificus is an opportunistic human pathogen that can cause life-threatening sepsis in immunocompromised patients via seafood poisoning or wound infection. Among the toxic substances produced by this pathogen, the MARTX toxin greatly contributes to disease progression by promoting the dysfunction and death of host cells, which allows the bacteria to disseminate and colonize the host. In response to this, host cells mount a counterattack against the invaders by upregulating various defense genes. In this study, the gene expression profiles of both host cells and V. vulnificus were analyzed by RNA sequencing to gain a comprehensive understanding of host-pathogen interactions. Our results suggest that V. vulnificus uses the MARTX toxin to subvert host cell immune responses as well as to oppose host counterattacks such as iron limitation.
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Hernández-Cabanyero C, Amaro C. Phylogeny and life cycle of the zoonotic pathogen Vibrio vulnificus. Environ Microbiol 2020; 22:4133-4148. [PMID: 32567215 DOI: 10.1111/1462-2920.15137] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 01/08/2023]
Abstract
Vibrio vulnificus is a zoonotic pathogen able to cause diseases in humans and fish that occasionally result in sepsis and death. Most reviews about this pathogen (including those related to its ecology) are clearly biased towards its role as a human pathogen, emphasizing its relationship with oysters as its main reservoir, the role of the known virulence factors as well as the clinic and the epidemiology of the human disease. This review tries to give to the reader a wider vision of the biology of this pathogen covering aspects related to its phylogeny and evolution and filling the gaps in our understanding of the general strategies that V. vulnificus uses to survive outside and inside its two main hosts, the human and the eel, and how its response to specific environmental parameters determines its survival, its death, or the triggering of an infectious process.
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Affiliation(s)
| | - Carmen Amaro
- ERI-Biotecmed, University of Valencia, Dr. Moliner, 50, Valencia, 46100, Spain
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Choi G, Jang KK, Lim JG, Lee ZW, Im H, Choi SH. The transcriptional regulator IscR integrates host-derived nitrosative stress and iron starvation in activation of the vvhBA operon in Vibrio vulnificus. J Biol Chem 2020; 295:5350-5361. [PMID: 32169898 PMCID: PMC7170529 DOI: 10.1074/jbc.ra120.012724] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/09/2020] [Indexed: 12/30/2022] Open
Abstract
For successful infection of their hosts, pathogenic bacteria recognize host-derived signals that induce the expression of virulence factors in a spatiotemporal manner. The fulminating food-borne pathogen Vibrio vulnificus produces a cytolysin/hemolysin protein encoded by the vvhBA operon, which is a virulence factor preferentially expressed upon exposure to murine blood and macrophages. The Fe-S cluster containing transcriptional regulator IscR activates the vvhBA operon in response to nitrosative stress and iron starvation, during which the cellular IscR protein level increases. Here, electrophoretic mobility shift and DNase I protection assays revealed that IscR directly binds downstream of the vvhBA promoter P vvhBA , which is unusual for a positive regulator. We found that in addition to IscR, the transcriptional regulator HlyU activates vvhBA transcription by directly binding upstream of P vvhBA , whereas the histone-like nucleoid-structuring protein (H-NS) represses vvhBA by extensively binding to both downstream and upstream regions of its promoter. Of note, the binding sites of IscR and HlyU overlapped with those of H-NS. We further substantiated that IscR and HlyU outcompete H-NS for binding to the P vvhBA regulatory region, resulting in the release of H-NS repression and vvhBA induction. We conclude that concurrent antirepression by IscR and HlyU at regions both downstream and upstream of P vvhBA provides V. vulnificus with the means of integrating host-derived signal(s) such as nitrosative stress and iron starvation for precise regulation of vvhBA transcription, thereby enabling successful host infection.
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Affiliation(s)
- Garam Choi
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul 08826, South Korea
| | - Kyung Ku Jang
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul 08826, South Korea
| | - Jong Gyu Lim
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul 08826, South Korea
| | - Zee-Won Lee
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul 08826, South Korea
| | - Hanhyeok Im
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul 08826, South Korea
| | - Sang Ho Choi
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul 08826, South Korea.
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Melatonin restores Muc2 depletion induced by V. vulnificus VvpM via melatonin receptor 2 coupling with Gαq. J Biomed Sci 2020; 27:21. [PMID: 31906951 PMCID: PMC6943958 DOI: 10.1186/s12929-019-0606-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/19/2019] [Indexed: 12/21/2022] Open
Abstract
Background Melatonin (5-methoxy-N-acetyltryptamine), a hormone produced in the pineal gland, has a variety of biological functions as an antioxidant, but a functional role of melatonin in the regulation of intestinal mucin (Muc) production during bacterial infection has yet to be described in detail. In this study, we investigate the effects of melatonin during Muc2 repression elicited by the Gram-negative bacterium V. vulnificus. Methods Mucus-secreting human HT29-MTX cells were used to study the functional role of melatonin during Muc2 depletion induced by the recombinant protein (r) VvpM produced by V. vulnificus. The regulatory effects of melatonin coupling with melatonin receptor 2 (MT2) on the production of reactive oxygen species (ROS), the activation of PKCδ and ERK, and the hypermethylation of the Muc2 promoter as induced by rVvpM were examined. Experimental mouse models of V. vulnificus infection were used to study the role of melatonin and how it neutralizes the bacterial toxin activity related to Muc2 repression. Results Recombinant protein (r) VvpM significantly reduced the level of Muc2 in HT29-MTX cells. The repression of Muc2 induced by rVvpM was significantly restored upon a treatment with melatonin (1 μM), which had been inhibited by the knockdown of MT2 coupling with Gαq and the NADPH oxidase subunit p47 phox. Melatonin inhibited the ROS-mediated phosphorylation of PKCδ and ERK responsible for region-specific hypermethylation in the Muc2 promoter in rVvpM-treated HT29-MTX cells. In the mouse models of V. vulnificus infection, treatment with melatonin maintained the level of Muc2 expression in the intestine. In addition, the mutation of the VvpM gene from V. vulnificus exhibited an effect similar to that of melatonin. Conclusions These results demonstrate that melatonin acting on MT2 inhibits the hypermethylation of the Muc2 promoter to restore the level of Muc2 production in intestinal epithelial cells infected with V. vulnificus.
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Imdad S, Batool N, Pradhan S, Chaurasia AK, Kim KK. Identification of 2',4'-Dihydroxychalcone as an Antivirulence Agent Targeting HlyU, a Master Virulence Regulator in Vibrio vulnificus. Molecules 2018; 23:E1492. [PMID: 29925801 PMCID: PMC6099652 DOI: 10.3390/molecules23061492] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/14/2018] [Accepted: 06/19/2018] [Indexed: 12/14/2022] Open
Abstract
The emergence of antimicrobial resistance and rapid acclimation allows Vibrio vulnificus to rapidly propagate in the host. This problematic pathological scenario can be circumvented by employing an antivirulence strategy, treating Vibrio infections without hindering the bacterial growth. We developed a genome-integrated orthogonal inhibitor screening platform in E. coli to identify antivirulence agents targeting a master virulence regulator of V. vulnificus. We identified 2′,4′-dihydroxychalcone (DHC) from the natural compound library and verified that it decreases the expression of the major toxin network which is equivalent to the ∆hlyU deletion mutant. 2′,4′-DHC also reduced the hemolytic activity of V. vulnificus which was tested as an example of virulence phenotype. The electrophoretic mobility shift assay confirmed that 2′,4′-DHC specifically targeted HlyU and inhibited its binding to PrtxA1 promoter. Under in vivo conditions, a single dose of 2′,4′-DHC protected ~50% wax-worm larvae from V. vulnificus infection at a non-toxic concentration to both V. vulnificus and wax-worm larvae. In the current study, we demonstrated that an orthogonal reporter system is suitable for the identification of antivirulence compounds with accuracy, and identified 2′,4′-DHC as a potent antivirulence agent that specifically targets the HlyU virulence transcriptional regulator and significantly reduces the virulence and infection potential of V. vulnificus.
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Affiliation(s)
- Saba Imdad
- Department of Molecular Cell Biology, School of Medicine, Samsung Medical Center, Sungkyunkwan University, Suwon 16419, Korea.
| | - Nayab Batool
- Department of Molecular Cell Biology, School of Medicine, Samsung Medical Center, Sungkyunkwan University, Suwon 16419, Korea.
| | - Subhra Pradhan
- Department of Molecular Cell Biology, School of Medicine, Samsung Medical Center, Sungkyunkwan University, Suwon 16419, Korea.
| | - Akhilesh Kumar Chaurasia
- Department of Molecular Cell Biology, School of Medicine, Samsung Medical Center, Sungkyunkwan University, Suwon 16419, Korea.
| | - Kyeong Kyu Kim
- Department of Molecular Cell Biology, School of Medicine, Samsung Medical Center, Sungkyunkwan University, Suwon 16419, Korea.
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Imdad S, Chaurasia AK, Kim KK. Identification and Validation of an Antivirulence Agent Targeting HlyU-Regulated Virulence in Vibrio vulnificus. Front Cell Infect Microbiol 2018; 8:152. [PMID: 29868508 PMCID: PMC5958221 DOI: 10.3389/fcimb.2018.00152] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/23/2018] [Indexed: 12/19/2022] Open
Abstract
Antimicrobial resistance (AMR) in pathogens is the result of indiscriminate use of antibiotics and consequent metabolic/genetic modulation to evolve survival strategies and clonal-selection in AMR strains. As an alternative to antibiotic treatment, antivirulence strategies are being developed, not only to combat bacterial pathogenesis, but also to avoid emerging antibiotic resistance. Vibrio vulnificus is a foodborne pathogen that causes gastroenteritis, necrotizing wound infections, and sepsis with a high rate of mortality. Here, we developed an inhibitor-screening reporter platform to target HlyU, a master transcriptional regulator of virulence factors in V. vulnificus by assessing rtxA1 transcription under its control. The inhibitor-screening platform includes wild type and ΔhlyU mutant strains of V. vulnificus harboring the reporter construct PrtxA1::luxCDABE for desired luminescence signal detection and control background luminescence, respectively. Using the inhibitor-screening platform, we identified a small molecule, fursultiamine hydrochloride (FTH), that inhibits the transcription of the highly invasive repeat-in-toxin (rtxA1) and hemolysin (vvhA) along with other HlyU regulated virulence genes. FTH has no cytotoxic effects on either host cells or pathogen at the tested concentrations. FTH rescues host cells from the necrotic cell-death induced by RtxA1 and decreases the hemolytic activity under in vitro conditions. The most important point is that FTH treatment does not induce the antivirulence resistance. Current study validated the antivirulence strategy targeting the HlyU virulence transcription factor and toxin-network of V. vulnificus and demonstrated that FTH, exhibits a potential to inhibit the pathogenesis of deadly, opportunistic human pathogen, V. vulnificus without inducing AMR.
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Affiliation(s)
- Saba Imdad
- Department of Molecular Cell Biology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Akhilesh Kumar Chaurasia
- Department of Molecular Cell Biology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Kyeong Kyu Kim
- Department of Molecular Cell Biology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, South Korea
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Sarvan S, Charih F, Askoura M, Butcher J, Brunzelle JS, Stintzi A, Couture JF. Functional insights into the interplay between DNA interaction and metal coordination in ferric uptake regulators. Sci Rep 2018; 8:7140. [PMID: 29739988 PMCID: PMC5940780 DOI: 10.1038/s41598-018-25157-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 04/11/2018] [Indexed: 12/19/2022] Open
Abstract
Ferric uptake regulators (Fur) are a family of transcription factors coupling gene regulatory events to metal concentration. Recent evidence has expanded the mechanistic repertoires employed by Fur to activate or repress gene expression in the presence or absence of regulatory metals. However, the mechanistic basis underlying this extended repertoire has remained largely unexplored. In this study, we used an extensive set of mutations to demonstrate that Campylobacter jejuni Fur (CjFur) employs the same surface to positively and negatively control gene expression regardless of the presence or absence of metals. Moreover, the crystal structure determination of a CjFur devoid of any regulatory metals shows that subtle reorientation of the transcription factor DNA binding domain negatively impacts DNA binding, gene expression and gut colonization in chickens. Overall, these results highlight the versatility of the CjFur DNA binding domain in mediating all gene regulatory events controlled by the metalloregulator and that the full metalation of CjFur is critical to the Campylobacter jejuni life cycle in vivo.
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Affiliation(s)
- Sabina Sarvan
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada
| | - François Charih
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada
| | - Momen Askoura
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada.,Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - James Butcher
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada
| | - Joseph S Brunzelle
- Feinberg School of Medicine, Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, Chicago, Illinois, 60611, USA
| | - Alain Stintzi
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada
| | - Jean-François Couture
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada.
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Repression of VvpM Protease Expression by Quorum Sensing and the cAMP-cAMP Receptor Protein Complex in Vibrio vulnificus. J Bacteriol 2018; 200:JB.00526-17. [PMID: 29339417 DOI: 10.1128/jb.00526-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 01/10/2018] [Indexed: 12/13/2022] Open
Abstract
Septicemia-causing Vibrio vulnificus produces at least three exoproteases, VvpE, VvpS, and VvpM, all of which participate in interactions with human cells. Expression of VvpE and VvpS is induced in the stationary phase by multiple transcription factors, including sigma factor S, SmcR, and the cAMP-cAMP receptor protein (cAMP-CRP) complex. Distinct roles of VvpM, such as induction of apoptosis, lead us to hypothesize VvpM expression is different from that of the other exoproteases. Its transcription, which was found to be independent of sigma S, is induced at the early exponential phase and then becomes negligible upon entry into the stationary phase. SmcR and CRP were studied regarding the control of vvpM expression. Transcription of vvpM was repressed by SmcR and cAMP-CRP complex individually, which specifically bound to the regions -2 to +20 and +6 to +27, respectively, relative to the vvpM transcription initiation site. Derepression of vvpM gene expression was 10- to 40-fold greater in an smcR crp double mutant than in single-gene mutants. Therefore, these results show that the expression of V. vulnificus exoproteases is differentially regulated, and in this way, distinct proteases can engage in specific interactions with a host.IMPORTANCE An opportunistic human pathogen, Vibrio vulnificus produces multiple extracellular proteases that are involved in diverse interactions with a host. The total exoproteolytic activity is detected mainly in the supernatants of the high-cell-density cultures. However, some proteolytic activity derived from a metalloprotease, VvpM, was present in the supernatants of the low-cell-density cultures sampled at the early growth period. In this study, we present the regulatory mechanism for VvpM expression via repression by at least two transcription factors. This type of transcriptional regulation is the exact opposite of those for expression of the other V. vulnificus exoproteases. Differential regulation of each exoprotease's production then facilitates the pathogen's participation in the distinct interactions with a host.
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Schwartz K, Kukuc C, Bier N, Taureck K, Hammerl JA, Strauch E. Diversity of Vibrio navarrensis Revealed by Genomic Comparison: Veterinary Isolates Are Related to Strains Associated with Human Illness and Sewage Isolates While Seawater Strains Are More Distant. Front Microbiol 2017; 8:1717. [PMID: 28932221 PMCID: PMC5592226 DOI: 10.3389/fmicb.2017.01717] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 08/24/2017] [Indexed: 12/30/2022] Open
Abstract
Strains of Vibrio navarrensis are present in aquatic environments like seawater, rivers, and sewage. Recently, strains of this species were identified in human clinical specimens. In this study, V. navarrensis strains isolated from livestock in Germany were characterized that were found in aborted fetuses and/or placentas after miscarriages. The veterinary strains were analyzed using phenotypical and genotypical methods and compared to isolates from marine environments of the Baltic Sea and North Sea. The investigated phenotypical traits were similar in all German strains. Whole genome sequencing (WGS) was used to evaluate a phylogenetic relationship by performing a single nucleotide polymorphism (SNP) analysis. For the SNP analysis, WGS data of two American human pathogenic strains and two Spanish environmental isolates from sewage were included. A phylogenetic analysis of concatenated sequences of five protein-coding housekeeping genes (gyrB, pyrH, recA, atpA, and rpoB), was additionally performed. Both phylogenetic analyses reveal a greater distance of the environmental seawater strains to the other strains. The phylogenetic tree constructed from concatenated sequences of housekeeping genes places veterinary, human pathogenic and Spanish sewage strains into one cluster. Presence and absence of virulence-associated genes were investigated based on WGS data and confirmed by PCR. However, this analysis showed no clear pattern for the potentially pathogenic strains. The detection of V. navarrensis in human clinical specimens strongly suggests that this species should be regarded as a potential human pathogen. The identification of V. navarrensis strains in domestic animals implicates a zoonotic potential of this species. This could indicate a potential threat for humans, as according to the “One Health” concept, human, animal, and environmental health are linked. Future studies are necessary to search for reservoirs of these bacteria in the environment and/or in living organisms.
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Affiliation(s)
- Keike Schwartz
- Department of Biological Safety, German Federal Institute for Risk AssessmentBerlin, Germany
| | - Cindy Kukuc
- Department of Biological Safety, German Federal Institute for Risk AssessmentBerlin, Germany
| | - Nadja Bier
- Department of Biological Safety, German Federal Institute for Risk AssessmentBerlin, Germany
| | - Karin Taureck
- Landesuntersuchungsanstalt für das Gesundheits- und Veterinärwesen SachsenDresden, Germany
| | - Jens A Hammerl
- Department of Biological Safety, German Federal Institute for Risk AssessmentBerlin, Germany
| | - Eckhard Strauch
- Department of Biological Safety, German Federal Institute for Risk AssessmentBerlin, Germany
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Jang KK, Lee ZW, Kim B, Jung YH, Han HJ, Kim MH, Kim BS, Choi SH. Identification and characterization of Vibrio vulnificus plpA encoding a phospholipase A 2 essential for pathogenesis. J Biol Chem 2017; 292:17129-17143. [PMID: 28855258 DOI: 10.1074/jbc.m117.791657] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/28/2017] [Indexed: 12/23/2022] Open
Abstract
The marine bacterium Vibrio vulnificus causes food-borne diseases, which may lead to life-threatening septicemia in some individuals. Therefore, identifying virulence factors in V. vulnificus is of high priority. We performed a transcriptome analysis on V. vulnificus after infection of human intestinal HT29-methotrexate cells and found induction of plpA, encoding a putative phospholipase, VvPlpA. Bioinformatics, biochemical, and genetic analyses demonstrated that VvPlpA is a phospholipase A2 secreted in a type II secretion system-dependent manner. Compared with the wild type, the plpA mutant exhibited reduced mortality, systemic infection, and inflammation in mice as well as low cytotoxicity toward the human epithelial INT-407 cells. Moreover, plpA mutation attenuated the release of actin and cytosolic cyclophilin A from INT-407 cells, indicating that VvPlpA is a virulence factor essential for causing lysis and necrotic death of the epithelial cells. plpA transcription was growth phase-dependent, reaching maximum levels during the early stationary phase. Also, transcription factor HlyU and cAMP receptor protein (CRP) mediate additive activation and host-dependent induction of plpA Molecular biological analyses revealed that plpA expression is controlled via the promoter, P plpA , and that HlyU and CRP directly bind to P plpA upstream sequences. Taken together, this study demonstrated that VvPlpA is a type II secretion system-dependent secretory phospholipase A2 regulated by HlyU and CRP and is essential for the pathogenicity of V. vulnificus.
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Affiliation(s)
- Kyung Ku Jang
- From the National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, and
| | - Zee-Won Lee
- From the National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, and
| | - Bityeoul Kim
- From the National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, and
| | - Young Hyun Jung
- the Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Medicine, BK21 PLUS Creative Veterinary Research Center, Seoul National University, Seoul 08826, South Korea and
| | - Ho Jae Han
- the Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Medicine, BK21 PLUS Creative Veterinary Research Center, Seoul National University, Seoul 08826, South Korea and
| | - Myung Hee Kim
- the Infection and Immunity Research Laboratory, Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, South Korea
| | - Byoung Sik Kim
- the Infection and Immunity Research Laboratory, Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, South Korea
| | - Sang Ho Choi
- From the National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, and
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14
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Lee SJ, Jung YH, Kim JS, Lee HJ, Lee SH, Lee KH, Jang KK, Choi SH, Han HJ. A Vibrio vulnificus VvpM Induces IL-1β Production Coupled with Necrotic Macrophage Death via Distinct Spatial Targeting by ANXA2. Front Cell Infect Microbiol 2017; 7:352. [PMID: 28848713 PMCID: PMC5554522 DOI: 10.3389/fcimb.2017.00352] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 07/21/2017] [Indexed: 12/23/2022] Open
Abstract
An inflammatory form of phagocyte death evoked by the Gram-negative bacterium Vibrio (V.) vulnificus (WT) is one of hallmarks to promote their colonization, but the virulence factor and infectious mechanism involved in this process remain largely unknown. Here, we identified extracellular metalloprotease VvpM as a new virulence factor and investigated the molecular mechanism of VvpM which acts during the regulation of the inflammatory form of macrophage death and bacterial colonization. Mutation of the vvpM gene appeared to play major role in the prevention of IL-1β production due to V. vulnificus infection in macrophage. However, the recombinant protein (r) VvpM caused IL-1β production coupled with necrotic cell death, which is highly susceptible to the knockdown of annexin A2 (ANXA2) located in both membrane lipid and non-lipid rafts. In lipid rafts, rVvpM recruited NOX enzymes coupled with ANXA2 to facilitate the production of ROS responsible for the epigenetic and transcriptional regulation of NF-κB in the IL-1β promoter. rVvpM acting on non-lipid rafts increased LC3 puncta formation and autophagic flux, which are required for the mRNA expression of Atg5 involved in the autophagosome formation process. The autophagy activation caused by rVvpM induced NLRP3 inflammasome-dependent caspase-1 activation in the promoting of IL-1β production. In mouse models of V. vulnificus infection, the VvpM mutant failed to elevate the level of pro-inflammatory responses closely related to IL-1β production and prevented bacterial colonization. These findings delineate VvpM efficiently regulates two pathogenic pathways that stimulate NF-κB-dependent IL-1β production and autophagy-mediated NLRP3 inflammasome via distinct spatial targeting by ANXA2.
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Affiliation(s)
- Sei-Jung Lee
- Department of Pharmaceutical Engineering, Daegu Haany UniversityGyeongsan, South Korea
| | - Young Hyun Jung
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science and BK21 PLUS Program for Creative Veterinary Science Research Center, Seoul National UniversitySeoul, South Korea
| | - Jun Sung Kim
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science and BK21 PLUS Program for Creative Veterinary Science Research Center, Seoul National UniversitySeoul, South Korea
| | - Hyun Jik Lee
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science and BK21 PLUS Program for Creative Veterinary Science Research Center, Seoul National UniversitySeoul, South Korea
| | - Sang Hun Lee
- Medical Science Research Institute, Soonchunhyang University Seoul HospitalSeoul, South Korea
- Departments of Biochemistry, Soonchunhyang University College of MedicineCheonan, South Korea
| | - Kyu-Ho Lee
- Department of Life Science, Sogang UniversitySeoul, South Korea
| | - Kyung Ku Jang
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Seoul National UniversitySeoul, South Korea
| | - Sang Ho Choi
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Seoul National UniversitySeoul, South Korea
| | - Ho Jae Han
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science and BK21 PLUS Program for Creative Veterinary Science Research Center, Seoul National UniversitySeoul, South Korea
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15
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Heng SP, Letchumanan V, Deng CY, Ab Mutalib NS, Khan TM, Chuah LH, Chan KG, Goh BH, Pusparajah P, Lee LH. Vibrio vulnificus: An Environmental and Clinical Burden. Front Microbiol 2017; 8:997. [PMID: 28620366 PMCID: PMC5449762 DOI: 10.3389/fmicb.2017.00997] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/17/2017] [Indexed: 12/14/2022] Open
Abstract
Vibrio vulnificus is a Gram negative, rod shaped bacterium that belongs to the family Vibrionaceae. It is a deadly, opportunistic human pathogen which is responsible for the majority of seafood-associated deaths worldwide. V. vulnificus infection can be fatal as it may cause severe wound infections potentially requiring amputation or lead to sepsis in susceptible individuals. Treatment is increasingly challenging as V. vulnificus has begun to develop resistance against certain antibiotics due to their indiscriminate use. This article aims to provide insight into the antibiotic resistance of V. vulnificus in different parts of the world as well as an overall review of its clinical manifestations, treatment, and prevention. Understanding the organism's antibiotic resistance profile is vital in order to select appropriate treatment and initiate appropriate prevention measures to treat and control V. vulnificus infections, which should eventually help lower the mortality rate associated with this pathogen worldwide.
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Affiliation(s)
- Sing-Peng Heng
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University MalaysiaBandar Sunway, Malaysia
| | - Vengadesh Letchumanan
- Division of Genetics and Molecular Biology, Faculty of Science, Institute of Biological Sciences, University of MalayaKuala Lumpur, Malaysia
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia
| | - Chuan-Yan Deng
- Zhanjiang Evergreen South Ocean Science and Technology CorporationGuangdong, China
| | - Nurul-Syakima Ab Mutalib
- UKM Medical Centre, UKM Medical Molecular Biology Institute, Universiti Kebangsaan MalaysiaKuala Lumpur, Malaysia
| | - Tahir M. Khan
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia
- Department of Pharmacy, Absyn University PeshawarPeshawar, Pakistan
| | - Lay-Hong Chuah
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Faculty of Science, Institute of Biological Sciences, University of MalayaKuala Lumpur, Malaysia
| | - Bey-Hing Goh
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia
- Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of PhayaoPhayao, Thailand
| | - Priyia Pusparajah
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University MalaysiaBandar Sunway, Malaysia
| | - Learn-Han Lee
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia
- Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of PhayaoPhayao, Thailand
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16
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Wen Y, Kim IH, Kim KS. Iron- and Quorum-sensing Signals Converge on Small Quorum-regulatory RNAs for Coordinated Regulation of Virulence Factors in Vibrio vulnificus. J Biol Chem 2016; 291:14213-14230. [PMID: 27151217 DOI: 10.1074/jbc.m116.714063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Indexed: 12/31/2022] Open
Abstract
Vibrio vulnificus is a marine bacterium that causes human infections resulting in high mortality. This pathogen harbors five quorum-regulatory RNAs (Qrr1-5) that affect the expression of pathogenicity genes by modulating the expression of the master regulator SmcR. The qrr genes are activated by phosphorylated LuxO to different degrees; qrr2 is strongly activated; qrr3 and qrr5 are moderately activated, and qrr1 and qrr4 are marginally activated and are the only two that do not respond to cell density-dependent regulation. Qrrs function redundantly to inhibit SmcR at low cell density and fully repress when all five are activated. In this study, we found that iron inhibits qrr expression in three distinct ways. First, the iron-ferric uptake regulator (Fur) complex directly binds to qrr promoter regions, inhibiting LuxO activation by competing with LuxO for cis-acting DNA elements. Second, qrr transcription is repressed by iron independently of Fur. Third, LuxO expression is repressed by iron independently of Fur. We also found that, under iron-limiting conditions, the five Qrrs functioned additively, not redundantly, to repress SmcR, suggesting that cells lacking iron enter a high cell density mode earlier and could thereby modulate expression of virulence factors sooner. This study suggests that iron and quorum sensing, along with their cognate regulatory circuits, are linked together in the coordinated expression of virulence factors.
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Affiliation(s)
- Yancheng Wen
- Department of Life Science, Sogang University, 35 Baekbeom-Ro, Mapo-Gu, Seoul 121-742, Korea
| | - In Hwang Kim
- Department of Life Science, Sogang University, 35 Baekbeom-Ro, Mapo-Gu, Seoul 121-742, Korea
| | - Kun-Soo Kim
- Department of Life Science, Sogang University, 35 Baekbeom-Ro, Mapo-Gu, Seoul 121-742, Korea; Interdisciplinary Program of Integrated Biotechnology, Sogang University, 35 Baekbeom-Ro, Mapo-Gu, Seoul 121-742, Korea.
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17
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Payne SM, Mey AR, Wyckoff EE. Vibrio Iron Transport: Evolutionary Adaptation to Life in Multiple Environments. Microbiol Mol Biol Rev 2016; 80:69-90. [PMID: 26658001 PMCID: PMC4711184 DOI: 10.1128/mmbr.00046-15] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Iron is an essential element for Vibrio spp., but the acquisition of iron is complicated by its tendency to form insoluble ferric complexes in nature and its association with high-affinity iron-binding proteins in the host. Vibrios occupy a variety of different niches, and each of these niches presents particular challenges for acquiring sufficient iron. Vibrio species have evolved a wide array of iron transport systems that allow the bacteria to compete for this essential element in each of its habitats. These systems include the secretion and uptake of high-affinity iron-binding compounds (siderophores) as well as transport systems for iron bound to host complexes. Transporters for ferric and ferrous iron not complexed to siderophores are also common to Vibrio species. Some of the genes encoding these systems show evidence of horizontal transmission, and the ability to acquire and incorporate additional iron transport systems may have allowed Vibrio species to more rapidly adapt to new environmental niches. While too little iron prevents growth of the bacteria, too much can be lethal. The appropriate balance is maintained in vibrios through complex regulatory networks involving transcriptional repressors and activators and small RNAs (sRNAs) that act posttranscriptionally. Examination of the number and variety of iron transport systems found in Vibrio spp. offers insights into how this group of bacteria has adapted to such a wide range of habitats.
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Affiliation(s)
- Shelley M Payne
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - Alexandra R Mey
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - Elizabeth E Wyckoff
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
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18
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Transgenic expression of omega-3 PUFA synthesis genes improves zebrafish survival during Vibrio vulnificus infection. J Biomed Sci 2015; 22:103. [PMID: 26572495 PMCID: PMC4647518 DOI: 10.1186/s12929-015-0208-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 10/16/2015] [Indexed: 02/04/2023] Open
Abstract
Background Highly desaturated n-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are synthesized by desaturases and elongase. They exert hepatoprotective effects to prevent alcoholic fatty liver syndrome or cholestatic liver injury. However, it is unclear how n-3 PUFAs improve immune function in liver. Vibrio vulnificus, a gram-negative bacterial pathogen, causes high mortality of aquaculture fishes upon infection. Humans can become infected with V. vulnificus through open wounds or by eating raw seafood, and such infections may result in systemic septicemia. Moreover, patients with liver diseases are vulnerable to infection, and are more likely than healthy persons to present with liver inflammation following infection. This study quantified n-3 PUFAs and their anti-bacterial effects in Fadsd6 and Elvol5a transgenic zebrafish. Results Two transgenic zebrafish strains with strong liver specific expression of Fadsd6 and Elvol5a (driven by the zebrafish Fabp10 promoter) were established using the Tol2 system. Synthesis of n-3 PUFAs in these strains were increased by 2.5-fold as compared to wild type (Wt) fish. The survival rate in 24 h following challenge with V. vulnificus was 20 % in Wt, but 70 % in the transgenic strains. In addition, the bacteria counts in transgenic fish strains were significantly decreased. The expression levels of pro-inflammatory genes, such as TNF-α, IL-1β, and NF-κB, were suppressed between 9 and 12 h after challenge. This study confirms the anti-bacterial function of n-3 PUFAs in a transgenic zebrafish model. Conclusions Fadsd6 and Elvol5a transgenic zebrafish are more resistant to V. vulnificus infection, and enhance survival by diminishing the attendant inflammatory response. Electronic supplementary material The online version of this article (doi:10.1186/s12929-015-0208-1) contains supplementary material, which is available to authorized users.
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19
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León-Sicairos N, Angulo-Zamudio UA, de la Garza M, Velázquez-Román J, Flores-Villaseñor HM, Canizalez-Román A. Strategies of Vibrio parahaemolyticus to acquire nutritional iron during host colonization. Front Microbiol 2015. [PMID: 26217331 PMCID: PMC4496571 DOI: 10.3389/fmicb.2015.00702] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Iron is an essential element for the growth and development of virtually all living organisms. As iron acquisition is critical for the pathogenesis, a host defense strategy during infection is to sequester iron to restrict the growth of invading pathogens. To counteract this strategy, bacteria such as Vibrio parahaemolyticus have adapted to such an environment by developing mechanisms to obtain iron from human hosts. This review focuses on the multiple strategies employed by V. parahaemolyticus to obtain nutritional iron from host sources. In these strategies are included the use of siderophores and xenosiderophores, proteases and iron-protein receptor. The host sources used by V. parahaemolyticus are the iron-containing proteins transferrin, hemoglobin, and hemin. The implications of iron acquisition systems in the virulence of V. parahaemolyticus are also discussed.
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Affiliation(s)
- Nidia León-Sicairos
- Unidad de Investigación, Facultad de Medicina, Universidad Autónoma de Sinaloa Culiacán, Mexico ; Departamento de Investigación, Hospital Pediátrico de Sinaloa "Dr. Rigoberto Aguilar Pico" Culiacán, Mexico
| | - Uriel A Angulo-Zamudio
- Maestría en Ciencias de la Salud, Facultad de Medicina, Universidad Autónoma de Sinaloa Culiacán, Mexico
| | - Mireya de la Garza
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Mexico, Mexico
| | - Jorge Velázquez-Román
- Unidad de Investigación, Facultad de Medicina, Universidad Autónoma de Sinaloa Culiacán, Mexico
| | | | - Adrian Canizalez-Román
- Unidad de Investigación, Facultad de Medicina, Universidad Autónoma de Sinaloa Culiacán, Mexico
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20
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Liu L, Chi H, Sun L. Pseudomonas fluorescens: identification of Fur-regulated proteins and evaluation of their contribution to pathogenesis. DISEASES OF AQUATIC ORGANISMS 2015; 115:67-80. [PMID: 26119301 DOI: 10.3354/dao02874] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Pseudomonas fluorescens is a Gram-negative bacterium and a common pathogen to a wide range of farmed fish. In a previous study, we found that the ferric uptake regulator gene (fur) is essential to the infectivity of a pathogenic fish isolate of P. fluorescens (wild-type strain TSS). In the present work, we conducted comparative proteomic analysis to examine the global protein profiles of TSS and the P. fluorescens fur knockout mutant TFM. Twenty-eight differentially produced proteins were identified, which belong to different functional categories. Four of these proteins, viz. TssP (a type VI secretion protein), PspA (a serine protease), OprF (an outer membrane porin), and ClpP (the proteolytic subunit of an ATP-dependent Clp protease), were assessed for virulence participation in a model of turbot Scophthalmus maximus. The results showed that the oprF and clpP knockouts exhibited significantly reduced capacities in (1) resistance against the bactericidal effect of host serum, (2) dissemination into and colonization of host tissues, and (3) inducing host mortality. In contrast, mutation of tssP and pspA had no apparent effect on the pathogenicity of TSS. Purified recombinant OprF, when used as a subunit vaccine, induced production of specific serum antibodies in immunized fish and elicited significant protection against lethal TSS challenge. Antibody blocking of the OprF in TSS significantly impaired the ability of the bacteria to invade host tissues. Taken together, these results indicate for the first time that in pathogenic P. fluorescens, Fur regulates the expression of diverse proteins, some of which are required for optimal infection.
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Affiliation(s)
- Li Liu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, PR China
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21
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Kim JA, Park JH, Lee MA, Lee HJ, Park SJ, Kim KS, Choi SH, Lee KH. Stationary-phase induction of vvpS expression by three transcription factors: repression by LeuO and activation by SmcR and CRP. Mol Microbiol 2015; 97:330-46. [PMID: 25869813 DOI: 10.1111/mmi.13028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2015] [Indexed: 11/27/2022]
Abstract
An exoprotease of Vibrio vulnificus, VvpS, exhibits an autolytic function during the stationary phase. To understand how vvpS expression is controlled, the regulators involved in vvpS transcription and their regulatory mechanisms were investigated. LeuO was isolated in a ligand-fishing experiment, and experiments using a leuO-deletion mutant revealed that LeuO represses vvpS transcription. LeuO bound the extended region including LeuO-binding site (LBS)-I and LBS-II. Further screening of additional regulators revealed that SmcR and cyclic adenosine monophosphate-receptor protein (CRP) play activating roles in vvpS transcription. SmcR and CRP bound the regions overlapping LBS-I and -II, respectively. In addition, the LeuO occupancy of LBS-I and LBS-II was competitively exchanged by SmcR and CRP, respectively. To examine the mechanism of stationary-phase induction of vvpS expression, in vivo levels of three transcription factors were monitored. Cellular level of LeuO was maximal at exponential phase, while those of SmcR and CRP were maximal at stationary phase and relatively constant after the early-exponential phase, respectively. Thus, vvpS transcription was not induced during the exponential phase by high cellular content of LeuO. When entering the stationary phase, however, LeuO content was significantly reduced and repression by LeuO was relieved through simultaneous binding of SmcR and CRP to LBS-I and -II, respectively.
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Affiliation(s)
- Jeong-A Kim
- Department of Life Science, Sogang University, Seoul, 121-742, South Korea
| | - Jin Hwan Park
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Seoul National University, Seoul, 151-921, South Korea
| | - Mi-Ae Lee
- Department of Life Science, Sogang University, Seoul, 121-742, South Korea
| | - Hyun-Jung Lee
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 120-752, South Korea
| | - Soon-Jung Park
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 120-752, South Korea
| | - Kun-Soo Kim
- Department of Life Science, Sogang University, Seoul, 121-742, South Korea
| | - Sang-Ho Choi
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Seoul National University, Seoul, 151-921, South Korea
| | - Kyu-Ho Lee
- Department of Life Science, Sogang University, Seoul, 121-742, South Korea
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22
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VvpM, an extracellular metalloprotease of Vibrio vulnificus, induces apoptotic death of human cells. J Microbiol 2014; 52:1036-43. [PMID: 25363631 DOI: 10.1007/s12275-014-4531-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 10/10/2014] [Accepted: 10/14/2014] [Indexed: 12/19/2022]
Abstract
A pathogenic bacterium, Vibrio vulnificus produces various extracellular proteases including the elastolytic metalloprotease, VvpE. In silico analysis of its genome revealed a VvpE-homologous protease, VvpM whose proteolytic activity was abolished by specific inhibitors against metalloproteases. To investigate whether this newly identified protease has pathogenic role in host interaction in addition to proteolytic role, human cell lines were incubated with recombinant VvpM (rVvpM). rVvpM-challenged cells showed typical morphological changes found in cells under apoptosis. Apoptotic cell death was further evidenced by estimating the Annexin V-stained cells, whose proportions were dependent upon the concentrations of rVvpM treated to human cells. To elucidate the signaling pathway for VvpM-induced apoptosis, three MAPKs were tested if their activation were mediated by rVvpM. ERK1/2 was phosphorylated by treatment of rVvpM and rVvpM-induced cell death was blocked by a specific inhibitor against ERK1/2. In rVvpM-treated cells, the cytosolic levels of cytochrome c were increased in a VvpM concentration-dependent manner, while the levels of cytochrome c in mitochondria were decreased. Cell deaths were accompanied by apparent cleavages of procaspases-9 and -3 to the active caspases-9 and -3, respectively. Therefore, this study demonstrates that an extracellular metalloprotease of V. vulnificus, VvpM induces apoptosis of human cells via a pathway consisting of ERK activation, cytochrome c release, and then activation of caspases-9 and -3.
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23
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Vanhove AS, Duperthuy M, Charrière GM, Le Roux F, Goudenège D, Gourbal B, Kieffer-Jaquinod S, Couté Y, Wai SN, Destoumieux-Garzón D. Outer membrane vesicles are vehicles for the delivery ofVibrio tasmaniensisvirulence factors to oyster immune cells. Environ Microbiol 2014; 17:1152-65. [DOI: 10.1111/1462-2920.12535] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 06/08/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Audrey Sophie Vanhove
- Ecology of Coastal Marine Systems; CNRS UMR 5119; Montpellier F-34095 France
- Ecology of Coastal Marine Systems; Ifremer; Montpellier F-34095 France
- Ecology of Coastal Marine Systems; University of Montpellier 1; Montpellier F-34095 France
- Ecology of Coastal Marine Systems; University of Montpellier 2 and IRD; Montpellier F-34095 France
| | - Marylise Duperthuy
- Ecology of Coastal Marine Systems; Ifremer; Montpellier F-34095 France
- Department of Molecular Biology; The Laboratory for Molecular Infection Medicine Sweden (MIMS); Umeå University; Umeå S-90187 Sweden
| | - Guillaume M. Charrière
- Ecology of Coastal Marine Systems; CNRS UMR 5119; Montpellier F-34095 France
- Ecology of Coastal Marine Systems; Ifremer; Montpellier F-34095 France
- Ecology of Coastal Marine Systems; University of Montpellier 1; Montpellier F-34095 France
- Ecology of Coastal Marine Systems; University of Montpellier 2 and IRD; Montpellier F-34095 France
| | - Frédérique Le Roux
- Unité Physiologie Fonctionnelle des Organismes Marins; Ifremer; Plouzané F-29280 France
- Integrative Biology of Marine Models UPMC Univ Paris 06; Sorbonne Universités; Roscoff Cedex F-29688 France
- Integrative Biology of Marine Models; CNRS UMR 8227; Station Biologique de Roscoff; Roscoff Cedex F-29688 France
| | - David Goudenège
- Unité Physiologie Fonctionnelle des Organismes Marins; Ifremer; Plouzané F-29280 France
- Integrative Biology of Marine Models UPMC Univ Paris 06; Sorbonne Universités; Roscoff Cedex F-29688 France
- Integrative Biology of Marine Models; CNRS UMR 8227; Station Biologique de Roscoff; Roscoff Cedex F-29688 France
| | - Benjamin Gourbal
- Ecology and Evolution of Interactions; CNRS UMR 5244; Université de Perpignan Via Domitia; Perpignan Cedex F-66860 France
| | - Sylvie Kieffer-Jaquinod
- U1038; Université Grenoble-Alpes; Grenoble F-38054 France
- iRTSV; Biologie à Grande Echelle; CEA; Grenoble F-38054 France
- U1038; INSERM; Grenoble F-38054 France
| | - Yohann Couté
- U1038; Université Grenoble-Alpes; Grenoble F-38054 France
- iRTSV; Biologie à Grande Echelle; CEA; Grenoble F-38054 France
- U1038; INSERM; Grenoble F-38054 France
| | - Sun Nyunt Wai
- Department of Molecular Biology; The Laboratory for Molecular Infection Medicine Sweden (MIMS); Umeå University; Umeå S-90187 Sweden
| | - Delphine Destoumieux-Garzón
- Ecology of Coastal Marine Systems; CNRS UMR 5119; Montpellier F-34095 France
- Ecology of Coastal Marine Systems; Ifremer; Montpellier F-34095 France
- Ecology of Coastal Marine Systems; University of Montpellier 1; Montpellier F-34095 France
- Ecology of Coastal Marine Systems; University of Montpellier 2 and IRD; Montpellier F-34095 France
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Lim JG, Choi SH. IscR is a global regulator essential for pathogenesis of Vibrio vulnificus and induced by host cells. Infect Immun 2014; 82:569-78. [PMID: 24478072 PMCID: PMC3911388 DOI: 10.1128/iai.01141-13] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 11/11/2013] [Indexed: 12/12/2022] Open
Abstract
A mutant that exhibited less cytotoxic activity toward INT-407 human intestinal epithelial cells than the wild type was screened from a random transposon mutant library of Vibrio vulnificus, and an open reading frame encoding an Fe-S cluster regulator, IscR, was identified using a transposon-tagging method. A mutational analysis demonstrated that IscR contributes to mouse mortality as well as cytotoxicity toward the INT-407 cells, indicating that IscR is essential for the pathogenesis of V. vulnificus. A whole-genome microarray analysis revealed that IscR influenced the expression of 67 genes, of which 52 were upregulated and 15 were downregulated. Among these, 12 genes most likely involved in motility and adhesion to host cells, hemolytic activity, and survival under oxidative stress of the pathogen during infection were selected and experimentally verified to be upregulated by IscR. Accordingly, the disruption of iscR resulted in a significant reduction in motility and adhesion to INT-407 cells, in hemolytic activity, and in resistance to reactive oxygen species (ROS) such as H2O2 and tert-butyl hydroperoxide (t-BOOH). Furthermore, the present study demonstrated that iscR expression was induced by exposure of V. vulnificus to the INT-407 cells, and the induction appeared to be mediated by ROS generated by the host cells during infection. Consequently, the combined results indicated that IscR is a global regulator that contributes to the overall success in the pathogenesis of V. vulnificus by regulating the expression of various virulence and survival genes in addition to Fe-S cluster genes.
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Affiliation(s)
- Jong Gyu Lim
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Seoul National University, Seoul, South Korea
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Lee HJ, Kim JA, Lee MA, Park SJ, Lee KH. Measurement of Haemolysin Activities in Vibrio vulnificus. Bio Protoc 2014. [DOI: 10.21769/bioprotoc.1062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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Troxell B, Hassan HM. Transcriptional regulation by Ferric Uptake Regulator (Fur) in pathogenic bacteria. Front Cell Infect Microbiol 2013; 3:59. [PMID: 24106689 PMCID: PMC3788343 DOI: 10.3389/fcimb.2013.00059] [Citation(s) in RCA: 290] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 09/18/2013] [Indexed: 12/16/2022] Open
Abstract
In the ancient anaerobic environment, ferrous iron (Fe2+) was one of the first metal cofactors. Oxygenation of the ancient world challenged bacteria to acquire the insoluble ferric iron (Fe3+) and later to defend against reactive oxygen species (ROS) generated by the Fenton chemistry. To acquire Fe3+, bacteria produce low-molecular weight compounds, known as siderophores, which have extremely high affinity for Fe3+. However, during infection the host restricts iron from pathogens by producing iron- and siderophore-chelating proteins, by exporting iron from intracellular pathogen-containing compartments, and by limiting absorption of dietary iron. Ferric Uptake Regulator (Fur) is a transcription factor which utilizes Fe2+ as a corepressor and represses siderophore synthesis in pathogens. Fur, directly or indirectly, controls expression of enzymes that protect against ROS damage. Thus, the challenges of iron homeostasis and defense against ROS are addressed via Fur. Although the role of Fur as a repressor is well-documented, emerging evidence demonstrates that Fur can function as an activator. Fur activation can occur through three distinct mechanisms (1) indirectly via small RNAs, (2) binding at cis regulatory elements that enhance recruitment of the RNA polymerase holoenzyme (RNAP), and (3) functioning as an antirepressor by removing or blocking DNA binding of a repressor of transcription. In addition, Fur homologs control defense against peroxide stress (PerR) and control uptake of other metals such as zinc (Zur) and manganese (Mur) in pathogenic bacteria. Fur family members are important for virulence within bacterial pathogens since mutants of fur, perR, or zur exhibit reduced virulence within numerous animal and plant models of infection. This review focuses on the breadth of Fur regulation in pathogenic bacteria.
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Affiliation(s)
- Bryan Troxell
- Department of Immunology and Microbiology, Indiana University School of Medicine Indianapolis, IN, USA
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