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Zhang Y, Zhang T, Qiu Y, Zhang M, Lu X, Yang W, Hu L, Zhou D, Gao B, Lu R. Transcriptomic Profiles of Vibrio parahaemolyticus During Biofilm Formation. Curr Microbiol 2023; 80:371. [PMID: 37838636 DOI: 10.1007/s00284-023-03425-7] [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: 05/03/2023] [Accepted: 07/19/2023] [Indexed: 10/16/2023]
Abstract
Vibrio parahaemolyticus, the leading cause of bacterial seafood-associated gastroenteritis, can form biofilms. In this work, the gene expression profiles of V. parahaemolyticus during biofilm formation were investigated by transcriptome sequencing. A total of 183, 503, and 729 genes were significantly differentially expressed in the bacterial cells at 12, 24 and 48 h, respectively, compared with that at 6 h. Of these, 92 genes were consistently activated or repressed from 6 to 48 h. The genes involved in polar flagellum, chemotaxis, mannose-sensitive haemagglutinin type IV pili, capsular polysaccharide, type III secretion system 1 (T3SS1), T3SS2, thermostable direct hemolysin (TDH), type VI secretion system 1 (T6SS1) and T6SS2 were downregulated, whereas those involved in V. parahaemolyticus pathogenicity island (Vp-PAI) (except for T3SS2 and TDH) and membrane fusion proteins were upregulated. Three extracellular protease genes (vppC, prtA and VPA1071) and a dozen of outer membrane protein encoding genes were also significantly differentially expressed during biofilm formation. In addition, five putative c-di-GMP metabolism-associated genes were significantly differentially expressed, which may account for the drop in c-di-GMP levels after the beginning of biofilm formation. Moreover, many putative regulatory genes were significantly differentially expressed, and more than 1000 putative small non-coding RNAs were detected, suggesting that biofilm formation was tightly regulated by complex regulatory networks. The data provided a global view of gene expression profiles during biofilm formation, showing that the significantly differentially expressed genes were involved in multiple cellular pathways, including virulence, biofilm formation, metabolism, and regulation.
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Affiliation(s)
- Yiquan Zhang
- Department of Clinical Laboratory, Affiliated Nantong Hospital 3 of Nantong University, Nantong, 226006, Jiangsu, China
- Department of Clinical Laboratory, Nantong Third People's Hospital, Nantong, 226006, Jiangsu, China
| | - Tingting Zhang
- Department of Clinical Laboratory, Affiliated Nantong Hospital 3 of Nantong University, Nantong, 226006, Jiangsu, China
- Department of Clinical Laboratory, Nantong Third People's Hospital, Nantong, 226006, Jiangsu, China
| | - Yue Qiu
- Department of Clinical Laboratory, The Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University, Changzhou, 213000, Jiangsu, China
| | - Miaomiao Zhang
- Department of Clinical Laboratory, Affiliated Nantong Hospital 3 of Nantong University, Nantong, 226006, Jiangsu, China
- Department of Clinical Laboratory, Nantong Third People's Hospital, Nantong, 226006, Jiangsu, China
| | - Xiuhui Lu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China
| | - Wenhui Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China
| | - Lingfei Hu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China
| | - Bo Gao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071, China.
| | - Renfei Lu
- Department of Clinical Laboratory, Affiliated Nantong Hospital 3 of Nantong University, Nantong, 226006, Jiangsu, China.
- Department of Clinical Laboratory, Nantong Third People's Hospital, Nantong, 226006, Jiangsu, China.
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Ulhuq FR, Mariano G. Bacterial pore-forming toxins. MICROBIOLOGY (READING, ENGLAND) 2022; 168:001154. [PMID: 35333704 PMCID: PMC9558359 DOI: 10.1099/mic.0.001154] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 02/03/2022] [Indexed: 12/11/2022]
Abstract
Pore-forming toxins (PFTs) are widely distributed in both Gram-negative and Gram-positive bacteria. PFTs can act as virulence factors that bacteria utilise in dissemination and host colonisation or, alternatively, they can be employed to compete with rival microbes in polymicrobial niches. PFTs transition from a soluble form to become membrane-embedded by undergoing large conformational changes. Once inserted, they perforate the membrane, causing uncontrolled efflux of ions and/or nutrients and dissipating the protonmotive force (PMF). In some instances, target cells intoxicated by PFTs display additional effects as part of the cellular response to pore formation. Significant progress has been made in the mechanistic description of pore formation for the different PFTs families, but in several cases a complete understanding of pore structure remains lacking. PFTs have evolved recognition mechanisms to bind specific receptors that define their host tropism, although this can be remarkably diverse even within the same family. Here we summarise the salient features of PFTs and highlight where additional research is necessary to fully understand the mechanism of pore formation by members of this diverse group of protein toxins.
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Affiliation(s)
- Fatima R. Ulhuq
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Giuseppina Mariano
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
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Yu G, Yu H, Yang Q, Wang J, Fan H, Liu G, Wang L, Bello BK, Zhao P, Zhang H, Dong J. Vibrio harveyi infections induce production of proinflammatory cytokines in murine peritoneal macrophages via activation of p38 MAPK and NF-κB pathways, but reversed by PI3K/AKT pathways. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 127:104292. [PMID: 34656643 DOI: 10.1016/j.dci.2021.104292] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 10/09/2021] [Accepted: 10/09/2021] [Indexed: 06/13/2023]
Abstract
Vibrio harveyi is a zoonotic pathogen that can infect humans through wounds and cause severe inflammatory responses. Previous studies have reported that the Toll like receptors (TLR) mediated MAPK, AKT and NF-κB signaling pathways are involved in innate immune system resistance to pathogen invasion. However, the molecular mechanism of these pathways, as well as their involvement in V. harveyi infection remains elusive. This study established a V. harveyi infection model using murine peritoneal macrophages (PMs). Various techniques, including western blotting, ELISA, RT-qPCR, immunofluorescence, inhibition assays, were used to explore the roles of TLRs, MAPK, AKT and NF-κB signaling pathways in V. harveyi-induced inflammatory responses. ELISA assays showed that V. harveyi infection triggered proinflammatory cytokines secretion in PMs. RT-qPCR and inhibition assays showed that TLR2 participated in V. harveyi infection and up-regulated the proinflammatory cytokines secretion in murine PMs. Western blotting data showed that the phosphorylation of p38, JNK, AKT, and NF-κB p65 were significantly increased partly mediated by TLR2. In addition, immunofluorescence assays revealed that the NF-κB p65 translocated into nucleus in response to V. harveyi infection. The secretion of IL-1β, IL-6, IL-12, and TNF-α were considerably reduced when the p38 MAPK and NF-κB signaling pathways were blocked, whereas blocking of AKT significantly increased the expression of IL-1β, IL-6, IL-12, and TNF-α. These findings indicate that V. harveyi infection induces inflammatory responses in murine PMs via activation of p38 MAPK and NF-κB pathways, which are partly mediated by TLR2, but are inhibited by PI3K/AKT pathways.
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Affiliation(s)
- Guili Yu
- Jiangsu Key Laboratory of Marine Biological Resources and Environment, Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Hong Yu
- Jiangsu Key Laboratory of Marine Biological Resources and Environment, Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Qiankun Yang
- Jiangsu Key Laboratory of Marine Biological Resources and Environment, Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Jinxin Wang
- Jiangsu Key Laboratory of Marine Biological Resources and Environment, Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Hui Fan
- Jiangsu Key Laboratory of Marine Biological Resources and Environment, Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Gang Liu
- Jiangsu Key Laboratory of Marine Biological Resources and Environment, Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Lei Wang
- Jiangsu Key Laboratory of Marine Biological Resources and Environment, Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China; Department of Vascular Surgery, The First People's Hospital of Lianyungang, Lianyungang, 222002, China
| | | | - Panpan Zhao
- Jiangsu Key Laboratory of Marine Biological Resources and Environment, Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China; Key Laboratory of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, 130062, PR China.
| | - Honggang Zhang
- Department of Vascular Surgery, The First People's Hospital of Lianyungang, Lianyungang, 222002, China.
| | - Jingquan Dong
- Jiangsu Key Laboratory of Marine Biological Resources and Environment, Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005, China.
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Xu Y, Yang L, Wang Y, Zhu Z, Yan J, Qin S, Chen L. Prophage-encoded gene VpaChn25_0734 amplifies ecological persistence of Vibrio parahaemolyticus CHN25. Curr Genet 2022; 68:267-287. [PMID: 35064802 PMCID: PMC8783578 DOI: 10.1007/s00294-022-01229-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/03/2021] [Accepted: 12/31/2021] [Indexed: 12/19/2022]
Abstract
Vibrio parahaemolyticus is a waterborne pathogen that can cause acute gastroenteritis, wound infection, and septicemia in humans. The molecular basis of its pathogenicity is not yet fully understood. Phages are found most abundantly in aquatic environments and play a critical role in horizontal gene transfer. Nevertheless, current literature on biological roles of prophage-encoded genes remaining in V. parahaemolyticus is rare. In this study, we characterized one such gene VpaChn25_0734 (543-bp) in V. parahaemolyticus CHN25 genome. A deletion mutant ΔVpaChn25_0734 (543-bp) was obtained by homologous recombination, and a revertant ΔVpaChn25_0734-com (543-bp) was also constructed. The ΔVpaChn25_0734 (543-bp) mutant was defective in growth and swimming mobility particularly at lower temperatures and/or pH 7.0–8.5. Cell surface hydrophobicity and biofilm formation were significantly decreased in the ΔVpaChn25_0734 (543-bp) mutant (p < 0.05). Based on the in vitro Caco-2 cell model, the deletion of VpaChn25_0734 (543-bp) gene significantly reduced the cytotoxicity of V. parahaemolyticus CHN25 to human intestinal epithelial cells (p < 0.05). Comparative secretomic and transcriptomic analyses revealed a slightly increased extracellular proteins, and thirteen significantly changed metabolic pathways in the ΔVpaChn25_0734 (543-bp) mutant, showing down-regulated carbon source transport and utilization, biofilm formation, and type II secretion system (p < 0.05), consistent with the observed defective phenotypes. Taken, the prophage-encoded gene VpaChn25_0734 (543-bp) enhanced V. parahaemolyticus CHN25 fitness for survival in the environment and the host. The results in this study facilitate better understanding of pathogenesis and genome evolution of V. parahaemolyticus, the leading sea foodborne pathogen worldwide.
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Affiliation(s)
- Yingwei Xu
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture and Rural Affairs of the People's Republic of China, College of Food Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
| | - Lianzhi Yang
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture and Rural Affairs of the People's Republic of China, College of Food Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
| | - Yaping Wang
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture and Rural Affairs of the People's Republic of China, College of Food Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
- Department of Internal Medicine, Virginia Commonwealth University/McGuire VA Medical Centre, Richmond, VA, USA
| | - Zhuoying Zhu
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture and Rural Affairs of the People's Republic of China, College of Food Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
| | - Jizhou Yan
- College of Fishers and Life Science, Shanghai Ocean University, Shanghai, 201306, China
| | - Si Qin
- Key Laboratory for Food Science and Biotechnology of Hunan Province, College of Food Science and Technology, Hunan Agricultural University, Changsha, 410128, China.
| | - Lanming Chen
- Key Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture and Rural Affairs of the People's Republic of China, College of Food Science and Technology, Shanghai Ocean University, Shanghai, 201306, China.
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Microfluidic thread-based electrochemical aptasensor for rapid detection of Vibrio parahaemolyticus. Biosens Bioelectron 2021; 182:113191. [PMID: 33780852 DOI: 10.1016/j.bios.2021.113191] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 03/12/2021] [Accepted: 03/18/2021] [Indexed: 12/14/2022]
Abstract
Vibrio parahaemolyticus is one of the foodborne bacteria that widely present in seafood as well as the leading cause of seafood-associated bacterial gastroenteritis. Traditional identification of such pathogens mainly relies on culturing methods, ELISA or PCR. These methods are usually laborious, time-consuming with poor diagnosis competences, or require costly and bulky equipment though of high sensitivity. In this study, a thread-based microfluidic electrochemical aptasensor was designed, fabricated and tested by using label-free aptamer immunosensing technology for rapid and highly sensitive detection of Vibrio parahaemolyticus in seafood. Both the microfluidic channels and electrodes were simply fabricated on threads. Molybdenum disulfide (MoS2) nanosheets were used to obtain enhanced sensitivity of the electrochemical measurement. When used in detecting Vibrio parahaemolyticus, the proposed aptasensor has a dynamic detection range of 10-106 CFU mL-1 with a detection limit of 5.74 CFU mL-1. Compared with traditional plate counting method, the proposed aptasensor has higher detection sensitivity and less assay time (30 min), while high specificity and accuracy are kept. The proposed microfluidic thread-based electrochemical aptasensor grabs the potential to detect other pathogens by simply functionalizing the threaded electrodes with aptamers for targeted biological substances.
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De Nisco NJ, Casey AK, Kanchwala M, Lafrance AE, Coskun FS, Kinch LN, Grishin NV, Xing C, Orth K. Manipulation of IRE1-Dependent MAPK Signaling by a Vibrio Agonist-Antagonist Effector Pair. mSystems 2021; 6:e00872-20. [PMID: 33563785 PMCID: PMC7883537 DOI: 10.1128/msystems.00872-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 01/19/2021] [Indexed: 12/05/2022] Open
Abstract
Diverse bacterial pathogens employ effector delivery systems to disrupt vital cellular processes in the host (N. M. Alto and K. Orth, Cold Spring Harbor Perspect Biol 4:a006114, 2012, https://doi.org/10.1101/cshperspect.a006114). The type III secretion system 1 of the marine pathogen Vibrio parahaemolyticus utilizes the sequential action of four effectors to induce a rapid, proinflammatory cell death uniquely characterized by a prosurvival host transcriptional response (D. L. Burdette, M. L. Yarbrough, A Orvedahl, C. J. Gilpin, and K. Orth, Proc Natl Acad Sci USA 105:12497-12502, 2008, https://doi.org/10.1073/pnas.0802773105; N. J. De Nisco, M. Kanchwala, P. Li, J. Fernandez, C. Xing, and K. Orth, Sci Signal 10:eaa14501, 2017, https://doi.org/10.1126/scisignal.aal4501). Herein, we show that this prosurvival response is caused by the action of the channel-forming effector VopQ that targets the host V-ATPase, resulting in lysosomal deacidification and inhibition of lysosome-autophagosome fusion. Recent structural studies have shown how VopQ interacts with the V-ATPase and, while in the ER, a V-ATPase assembly intermediate can interact with VopQ, causing a disruption in membrane integrity. Additionally, we observed that VopQ-mediated disruption of the V-ATPase activates the IRE1 branch of the unfolded protein response (UPR), resulting in an IRE1-dependent activation of ERK1/2 MAPK signaling. We also find that this early VopQ-dependent induction of ERK1/2 phosphorylation is terminated by the VopS-mediated inhibitory AMPylation of Rho GTPase signaling. Since VopS dampens VopQ-induced IRE1-dependent ERK1/2 activation, we propose that IRE1 activates ERK1/2 phosphorylation at or above the level of Rho GTPases. This study illustrates how temporally induced effectors can work as in tandem as agonist/antagonist to manipulate host signaling and reveals new connections between V-ATPase function, UPR, and MAPK signaling.IMPORTANCE Vibrio parahaemolyticus is a seafood-borne pathogen that encodes two type 3 secretion systems (T3SS). The first system, T3SS1, is thought to be maintained in all strains of V. parahaemolyticus to maintain survival in the environment, whereas the second system, T3SS2, is linked to clinical isolates and disease in humans. Here, we found that first system targets evolutionarily conserved signaling systems to manipulate host cells, eventually causing a rapid, orchestrated cells death within 3 h. We have found that the T3SS1 injects virulence factors that temporally manipulate host signaling. Within the first hour of infection, the effector VopQ acts first by activating host survival signals while diminishing the host cell apoptotic machinery. Less than an hour later, another effector, VopS, reverses activation and inhibition of these signaling systems, ultimately leading to death of the host cell. This work provides example of how pathogens have evolved to manipulate the interplay between T3SS effectors to regulate host signaling pathways.
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Affiliation(s)
- Nicole J De Nisco
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Amanda K Casey
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Mohammed Kanchwala
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Alexander E Lafrance
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Fatma S Coskun
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Lisa N Kinch
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Nick V Grishin
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Chao Xing
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Population and Data Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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S-nitrosylation-mediated activation of a histidine kinase represses the type 3 secretion system and promotes virulence of an enteric pathogen. Nat Commun 2020; 11:5777. [PMID: 33188170 PMCID: PMC7666205 DOI: 10.1038/s41467-020-19506-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 10/15/2020] [Indexed: 12/11/2022] Open
Abstract
Vibrio parahaemolyticus is the leading cause of seafood-borne diarrheal diseases. Experimental overproduction of a type 3 secretion system (T3SS1) in this pathogen leads to decreased intestinal colonization, which suggests that T3SS1 repression is required for maximal virulence. However, the mechanisms by which T3SS1 is repressed in vivo are unclear. Here, we show that host-derived nitrite modifies the activity of a bacterial histidine kinase and mediates T3SS1 repression. More specifically, nitrite activates histidine kinase sensor VbrK through S-nitrosylation on cysteine 86, which results in downregulation of the entire T3SS1 operon through repression of its positive regulator exsC. Replacement of cysteine 86 with a serine (VbrK C86S mutant) leads to increased expression of inflammatory cytokines in infected Caco-2 cells. In an infant rabbit model of infection, the VbrK C86S mutant induces a stronger inflammatory response at the early stage of infection, and displays reduced intestinal colonization and virulence at the later stage of infection, in comparison with the parent strain. Our results indicate that the pathogen V. parahaemolyticus perceives nitrite as a host-derived signal and responds by downregulating a proinflammatory factor (T3SS1), thus enhancing intestinal colonization and virulence. Vibrio parahaemolyticus causes seafood-borne diarrheal diseases. Here, the authors show that the pathogen uses a histidine kinase to sense host-derived nitrite and downregulate a proinflammatory type 3 secretion system, thus enhancing intestinal colonization and virulence.
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Type III Secretion Effector VopQ of Vibrio parahaemolyticus Modulates Central Carbon Metabolism in Epithelial Cells. mSphere 2020; 5:5/2/e00960-19. [PMID: 32188755 PMCID: PMC7082145 DOI: 10.1128/msphere.00960-19] [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] [Indexed: 12/19/2022] Open
Abstract
The metabolic response of host cells upon infection is pathogen specific, and infection-induced host metabolic reprogramming may have beneficial effects on the proliferation of pathogens. V. parahaemolyticus contains a range of virulence factors to manipulate host signaling pathways and metabolic processes. In this study, we identified that the T3SS1 VopQ effector rewrites host metabolism in conjunction with the inflammation and cell death processes. Understanding how VopQ reprograms host cell metabolism during the infection could help us to identify novel therapeutic strategies to enhance the survival of host cells during V. parahaemolyticus infection. Vibrio parahaemolyticus is a Gram-negative halophilic pathogen that frequently causes acute gastroenteritis and occasional wound infection. V. parahaemolyticus contains several virulence factors, including type III secretion systems (T3SSs) and thermostable direct hemolysin (TDH). In particular, T3SS1 is a potent cytotoxic inducer, and T3SS2 is essential for causing acute gastroenteritis. Although much is known about manipulation of host signaling transductions by the V. parahaemolyticus effector, little is known about the host metabolomic changes modulated by V. parahaemolyticus. To address this knowledge gap, we performed a metabolomic analysis of the epithelial cells during V. parahaemolyticus infection using capillary electrophoresis-time of flight mass spectrometry (CE-TOF/MS). Our results revealed significant metabolomic perturbations upon V. parahaemolyticus infection. Moreover, we identified that T3SS1’s VopQ effector was responsible for inducing the significant metabolic changes in the infected cells. The VopQ effector dramatically altered the host cell’s glycolytic, tricarboxylic acid cycle (TCA), and amino acid metabolisms. VopQ effector disrupted host cell redox homeostasis by depleting cellular glutathione and subsequently increasing the level of reactive oxygen species (ROS) production. IMPORTANCE The metabolic response of host cells upon infection is pathogen specific, and infection-induced host metabolic reprogramming may have beneficial effects on the proliferation of pathogens. V. parahaemolyticus contains a range of virulence factors to manipulate host signaling pathways and metabolic processes. In this study, we identified that the T3SS1 VopQ effector rewrites host metabolism in conjunction with the inflammation and cell death processes. Understanding how VopQ reprograms host cell metabolism during the infection could help us to identify novel therapeutic strategies to enhance the survival of host cells during V. parahaemolyticus infection.
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A Novel Mouse Model of Enteric Vibrio parahaemolyticus Infection Reveals that the Type III Secretion System 2 Effector VopC Plays a Key Role in Tissue Invasion and Gastroenteritis. mBio 2019; 10:mBio.02608-19. [PMID: 31848276 PMCID: PMC6918077 DOI: 10.1128/mbio.02608-19] [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] [Indexed: 12/13/2022] Open
Abstract
The Gram-negative marine bacterium Vibrio parahaemolyticus is a common cause of infectious gastroenteritis due to the ingestion of contaminated seafood. Most virulent V. parahaemolyticus strains encode two type III secretion systems (T3SS1 and T3SS2); however, the roles they and their translocated effectors play in causing intestinal disease remain unclear. While studies have identified T3SS1 effectors as responsible for killing epithelial cells in culture, the T3SS2 effectors caused massive epithelial cell disruption in a rabbit ileal loop model. Additional models are thus needed to clarify the pathogen-host interactions that drive V. parahaemolyticus-associated gastroenteritis. Germfree mice were infected with a pathogenic clinical isolate of V. parahaemolyticus, RIMD2210633 (RIMD). The pathogen was found to adhere to as well as invade the cecal mucosa, accompanied by severe inflammation and dramatic mucosal damage, including widespread sloughing of infected epithelial cells. Mice infected with a V. parahaemolyticus strain lacking the T3SS1 (POR2) also developed severe pathology, similar to that seen with RIMD. In contrast, the ΔT3SS2 strain (POR3) appeared unable to invade the intestinal mucosa or cause any mucosal pathology. Confirming a role for TS332 effectors, a strain expressing the T3SS2 but lacking VopC (POR2ΔvopC), a T3SS2 effector implicated in epithelial cell invasion in culture, was strongly attenuated in invading the intestinal mucosa and in causing gastroenteritis, although infection with this mutant resulted in more pathology than the ΔT3SS2 strain. We thus present an experimental system that enables further characterization of T3SS effectors as well as the corresponding host inflammatory response involved in the gastroenteritis caused by invasive V. parahaemolyticus IMPORTANCE Vibrio parahaemolyticus causes severe gastroenteritis following consumption of contaminated seafood. Global warming has allowed this pathogen to spread worldwide, contributing to recent outbreaks. Clinical isolates are known to harbor an array of virulence factors, including T3SS1 and T3SS2; however, the precise role these systems play in intestinal disease remains unclear. There is an urgent need to improve our understanding of how V. parahaemolyticus infects hosts and causes disease. We present a novel mouse model for this facultative intracellular pathogen and observe that the T3SS2 is essential to pathogenicity. Moreover, we show that the T3SS2 effector VopC, previously shown to be a Rac and Cdc42 deamidase that facilitates bacterial uptake by nonphagocytic cells, also plays a key role in the ability of V. parahaemolyticus to invade the intestinal mucosa and cause gastroenteritis. This experimental model thus provides a valuable tool for future elucidation of virulence mechanisms used by this facultative intracellular pathogen during in vivo infection.
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Wang S, Zhang Z, Malakar PK, Pan Y, Zhao Y. The Fate of Bacteria in Human Digestive Fluids: A New Perspective Into the Pathogenesis of Vibrio parahaemolyticus. Front Microbiol 2019; 10:1614. [PMID: 31379774 PMCID: PMC6648005 DOI: 10.3389/fmicb.2019.01614] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/28/2019] [Indexed: 01/23/2023] Open
Abstract
Vibrio parahaemolyticus causes the most seafood-attributed gastroenteritis outbreaks worldwide and studies on its pathogenesis during passage through the human digestive fluids are limited. An in vitro continuous model system mimicking passage through saliva, gastric and intestinal fluid was used to study the survival, morphology and virulence-related gene expression of a total of sixty pathogenic, and non-pathogenic V. parahaemolyticus strains. The changes to these three characteristics for the sixty V. parahaemolyticus strains were minimal on passage through the saliva fluid. No V. parahaemolyticus strains survived passage through gastric fluid with low pH values (2.0 and 3.0) and the cells, examined microscopically, were severely damaged. However, when the pH of gastric fluid increased to 4.0, the bacterial survival rate was 54.70 ± 1.11%, and the survival rate of pathogenic strains was higher when compared to non-pathogenic strains. Even though the bactericidal effect of intestinal fluid was lower than gastric fluid, virulence-related gene expression was enhanced in the intestinal fluid. Seafood matrices can significantly raise the pH level of gastric fluid and thus aid the survival of V. parahaemolyticus through passage from human gastric acid and progression of pathogenesis in the intestinal fluid. We confirmed these phenomena in the in vitro continuous digestion model.
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Affiliation(s)
- Siqi Wang
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Zhaohuan Zhang
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Pradeep K Malakar
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Yingjie Pan
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China.,Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Shanghai, China.,Shanghai Engineering Research Center of Aquatic-Product Processing and Preservation, Shanghai, China
| | - Yong Zhao
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China.,Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Shanghai, China.,Shanghai Engineering Research Center of Aquatic-Product Processing and Preservation, Shanghai, China
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11
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He L, Liang Y, Yu X, Peng W, He J, Fu L, Lin H, Zhang Y, Lu D. Vibrio parahaemolyticus flagellin induces cytokines expression via toll-like receptor 5 pathway in orange-spotted grouper, Epinephelus coioides. FISH & SHELLFISH IMMUNOLOGY 2019; 87:573-581. [PMID: 30721777 DOI: 10.1016/j.fsi.2019.01.054] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/29/2019] [Accepted: 01/31/2019] [Indexed: 06/09/2023]
Abstract
Vibrio parahaemolyticus is the major pathogen of vibriosis in aquatic animals and causes inflammation that may be related to tissue damage. Here, we have established a V. parahaemolyticus flagellin stimulation model using grouper spleen (GS) cell line. Purified V. parahaemolyticus flagellin was used to stimulate GS cells. Our results showed that the mRNA levels of orange-spotted grouper (Epinephelus coioides) toll-like receptor 5M (EcTLR5M), EcTLR5S and downstream cytokines, such as interferon-γ2 (IFN-γ2), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), were all significantly increased after stimulation with V. parahaemolyticus flagellin in GS cells. Gene silencing of the EcTLR5M and EcTLR5S in GS cells by using small interfering RNA resulted in suppression of the V. parahaemolyticus flagellin-induced cytokines expression. We further demonstrated that activation of both mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) were required for cytokines expression. We observed that the phosphorylation of NF-κB inhibitor-α (IκBα), extracellular signal-regulated kinase (ERK) and p38 were induced following treatment with flagellin. Additionally, most of p65, a NF-κB subunit, was found to translocate to the nucleus after 60 min stimulation. Overall, our results suggest that V. parahaemolyticus flagellin influences cytokines expression, such as IFN-γ2, IL-6 and TNF-α, via EcTLR5s recognition and MAPKs/NF-κB signaling pathway activation in GS cells.
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Affiliation(s)
- Liangge He
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory for Aquatic Economic Animals and Guangdong Provincial Engineering Technology Research Center for Healthy Breeding of Important Economic Fish, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China
| | - Yaosi Liang
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory for Aquatic Economic Animals and Guangdong Provincial Engineering Technology Research Center for Healthy Breeding of Important Economic Fish, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China
| | - Xue Yu
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory for Aquatic Economic Animals and Guangdong Provincial Engineering Technology Research Center for Healthy Breeding of Important Economic Fish, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China
| | - Wan Peng
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory for Aquatic Economic Animals and Guangdong Provincial Engineering Technology Research Center for Healthy Breeding of Important Economic Fish, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China; State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University, Guangzhou, 510275, PR China
| | - Jianan He
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory for Aquatic Economic Animals and Guangdong Provincial Engineering Technology Research Center for Healthy Breeding of Important Economic Fish, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China
| | - Lijun Fu
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory for Aquatic Economic Animals and Guangdong Provincial Engineering Technology Research Center for Healthy Breeding of Important Economic Fish, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China
| | - Haoran Lin
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory for Aquatic Economic Animals and Guangdong Provincial Engineering Technology Research Center for Healthy Breeding of Important Economic Fish, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, PR China; College of Ocean, Hainan University, Haikou, 570228, PR China
| | - Yong Zhang
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory for Aquatic Economic Animals and Guangdong Provincial Engineering Technology Research Center for Healthy Breeding of Important Economic Fish, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China; Key Laboratory for Tropical Marine Fishery Resource Protection and Utilization of Hainan Province, Hainan Tropical Ocean University, Sanya, 570228, PR China.
| | - Danqi Lu
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory for Aquatic Economic Animals and Guangdong Provincial Engineering Technology Research Center for Healthy Breeding of Important Economic Fish, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China.
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12
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Li L, Meng H, Gu D, Li Y, Jia M. Molecular mechanisms of Vibrio parahaemolyticus pathogenesis. Microbiol Res 2019; 222:43-51. [PMID: 30928029 DOI: 10.1016/j.micres.2019.03.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/27/2019] [Accepted: 03/07/2019] [Indexed: 12/12/2022]
Abstract
Vibrio parahaemolyticus is a Gram-negative halophilic bacterium that is mainly distributed in the seafood such as fish, shrimps and shellfish throughout the world. V. parahaemolyticus can cause diseases in marine aquaculture, leading to huge economic losses to the aquaculture industry. More importantly, it is also the leading cause of seafood-borne diarrheal disease in humans worldwide. With the development of animal model, next-generation sequencing as well as biochemical and cell biological technologies, deeper understanding of the virulence factors and pathogenic mechanisms of V. parahaemolyticus has been gained. As a globally transmitted pathogen, the pathogenicity of V. parahaemolyticus is closely related to a variety of virulence factors. This article comprehensively reviewed the molecular mechanisms of eight types of virulence factors: hemolysin, type III secretion system, type VI secretion system, adhesion factor, iron uptake system, lipopolysaccharide, protease and outer membrane proteins. This review comprehensively summarized our current understanding of the virulence factors in V. parahaemolyticus, which are potentially new targets for the development of therapeutic and preventive strategies.
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Affiliation(s)
- Lingzhi Li
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Hongmei Meng
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Dan Gu
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China.
| | - Yang Li
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Mengdie Jia
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
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13
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Miller KA, Tomberlin KF, Dziejman M. Vibrio variations on a type three theme. Curr Opin Microbiol 2019; 47:66-73. [PMID: 30711745 DOI: 10.1016/j.mib.2018.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 12/06/2018] [Accepted: 12/16/2018] [Indexed: 11/18/2022]
Abstract
Mounting evidence suggests that Type 3 Secretion Systems (T3SS) are widespread among Vibrio species, and are present in strains isolated from diverse sources such as human clinical infections, environmental reservoirs, and diseased marine life. Experiments evaluating Vibrio parahaemolyticus and Vibrio cholerae T3SS mediated virulence suggest that Vibrio T3SS pathogenicity islands have a tripartite composition. A conserved 'core' region encodes functions essential for colonization and disease in vivo, including modulation of innate immune signaling pathways and actin dynamics, whereas regions flanking core sequences are variable among strains and encode effector proteins performing a diverse array of activities. Characterizing novel functions associated with Vibrio-specific effectors is, therefore, essential for understanding how vibrios employ T3SS mechanisms to cause disease in a broad range of hosts and how T3SS island composition potentially defines species-specific disease.
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Affiliation(s)
- Kelly A Miller
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States
| | - Katharine F Tomberlin
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States
| | - Michelle Dziejman
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States.
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14
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Zhang Y, Hu L, Qiu Y, Osei-Adjei G, Tang H, Zhang Y, Zhang R, Sheng X, Xu S, Yang W, Yang H, Yin Z, Yang R, Huang X, Zhou D. QsvR integrates into quorum sensing circuit to control Vibrio parahaemolyticus virulence. Environ Microbiol 2019; 21:1054-1067. [PMID: 30623553 DOI: 10.1111/1462-2920.14524] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/22/2018] [Accepted: 01/05/2019] [Indexed: 11/29/2022]
Abstract
Vibrio parahaemolyticus, the leading cause of seafood-associated gastroenteritis worldwide, requires the two type-III secretion systems (T3SS1 and T3SS2) and a thermostable direct hemolysin (encoded by tdh1 and tdh2) for full virulence. The tdh genes and the T3SS2 gene cluster constitute an 80 kb pathogenicity island known as Vp-PAI located on the chromosome II. Expression of T3SS1 and Vp-PAI is regulated in a quorum sensing (QS)-dependent manner but its detailed mechanisms remain unknown. Herein, we show that three factors (QS regulators AphA and OpaR and an AraC-type transcriptional regulator QsvR) form a complex regulatory network to control the expression of T3SS1 and Vp-PAI genes. At low cell density (LCD), whereas Vp-PAI expression is repressed, T3SS1 genes are induced by AphA, which directly binds (an operator region of) the exsBAD-vscBCD operon. At high cell density (HCD), the bacterium turns off T3SS1 expression by replacing AphA with OpaR, triggering the induction of Vp-PAI. Furthermore, QsvR binds to the regulatory regions of all the tested T3SS1 and Vp-PAI genes to activate their transcription at HCD. Taken together, our data highlight how multiple QS regulators contribute to the pathogenicity of V. parahaemolyticus by precisely controlling the expression of major virulence determinants during different stages of growth.
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Affiliation(s)
- Yiquan Zhang
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, People's Republic of China
| | - Linghui Hu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
| | - Yue Qiu
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, People's Republic of China
| | - George Osei-Adjei
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, People's Republic of China
| | - Hao Tang
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, People's Republic of China
| | - Ying Zhang
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, People's Republic of China
| | - Rui Zhang
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, People's Republic of China
| | - Xiumei Sheng
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, People's Republic of China
| | - Shungao Xu
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, People's Republic of China
| | - Wenhui Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
| | - Huiying Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
| | - Zhe Yin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
| | - Xinxiang Huang
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, People's Republic of China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, People's Republic of China
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15
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Castillo D, Pérez-Reytor D, Plaza N, Ramírez-Araya S, Blondel CJ, Corsini G, Bastías R, Loyola DE, Jaña V, Pavez L, García K. Exploring the Genomic Traits of Non-toxigenic Vibrio parahaemolyticus Strains Isolated in Southern Chile. Front Microbiol 2018; 9:161. [PMID: 29472910 PMCID: PMC5809470 DOI: 10.3389/fmicb.2018.00161] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/24/2018] [Indexed: 01/30/2023] Open
Abstract
Vibrio parahaemolyticus is the leading cause of seafood-borne gastroenteritis worldwide. As reported in other countries, after the rise and fall of the pandemic strain in Chile, other post-pandemic strains have been associated with clinical cases, including strains lacking the major toxins TDH and TRH. Since the presence or absence of tdh and trh genes has been used for diagnostic purposes and as a proxy of the virulence of V. parahaemolyticus isolates, the understanding of virulence in V. parahaemolyticus strains lacking toxins is essential to detect these strains present in water and marine products to avoid possible food-borne infection. In this study, we characterized the genome of four environmental and two clinical non-toxigenic strains (tdh-, trh-, and T3SS2-). Using whole-genome sequencing, phylogenetic, and comparative genome analysis, we identified the core and pan-genome of V. parahaemolyticus of strains of southern Chile. The phylogenetic tree based on the core genome showed low genetic diversity but the analysis of the pan-genome revealed that all strains harbored genomic islands carrying diverse virulence and fitness factors or prophage-like elements that encode toxins like Zot and RTX. Interestingly, the three strains carrying Zot-like toxin have a different sequence, although the alignment showed some conserved areas with the zot sequence found in V. cholerae. In addition, we identified an unexpected diversity in the genetic architecture of the T3SS1 gene cluster and the presence of the T3SS2 gene cluster in a non-pandemic environmental strain. Our study sheds light on the diversity of V. parahaemolyticus strains from the southern Pacific which increases our current knowledge regarding the global diversity of this organism.
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Affiliation(s)
- Daniel Castillo
- Marine Biological Section, University of Copenhagen, Helsingør, Denmark
| | - Diliana Pérez-Reytor
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Nicolás Plaza
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Sebastián Ramírez-Araya
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile.,Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomás, Santiago, Chile
| | - Carlos J Blondel
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Gino Corsini
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Roberto Bastías
- Laboratory of Microbiology, Institute of Biology, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | | | - Víctor Jaña
- Facultad de Medicina Veterinaria y Agronomía, Universidad de Las Américas, Santiago, Chile
| | - Leonardo Pavez
- Facultad de Medicina Veterinaria y Agronomía, Universidad de Las Américas, Santiago, Chile.,Departamento de Ciencias Químicas y Biológicas, Universidad Bernardo O'Higgins, Santiago, Chile
| | - Katherine García
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
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16
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Asakawa S, Onodera R, Kasai K, Kishimoto Y, Sato T, Segawa R, Mizuno N, Ogasawara K, Moriya T, Hiratsuka M, Hirasawa N. Nickel ions bind to HSP90β and enhance HIF-1α-mediated IL-8 expression. Toxicology 2018; 395:45-53. [PMID: 29355601 DOI: 10.1016/j.tox.2018.01.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/04/2018] [Accepted: 01/12/2018] [Indexed: 01/07/2023]
Abstract
Nickel ions (Ni2+) eluted from biomedical devices cause inflammation and Ni allergy. Although Ni2+ and Co2+ elicit common effects, Ni2+ induces a generally stronger inflammatory reaction. However, the molecular mechanism by which Ni2+ and Co2+ induce such different responses remains to be elucidated. In the present study, we compared the effects of Ni2+ and Co2+ on the expression of interleukin (IL)-8 in human monocyte THP-1 cells. We report that NiCl2 but not CoCl2 induced the expression of IL-8; in contrast, CoCl2 elicited a higher expression of hypoxia-inducible factor-1α (HIF-1α). The NiCl2-induced expression of IL-8 in late phase was blocked by a HIF-1α inhibitor, PX-478, indicating that NiCl2 targets additional factors responsible for activating HIF-1α. To identify such targets, proteins that bound preferentially to Ni-NTA beads were analyzed by LC/MS/MS. The analysis yielded heat shock protein 90β (HSP90β) as a possible candidate. Furthermore, Ni2+ reduced the interaction of HSP90β with HIF-1α, and instead promoted the interaction between HIF-1α and HIF-1β, as well as the nuclear localization of HIF-1α. Using various deletion variants, we showed that Ni2+ could bind to the linker domain on HSP90β. These results suggest that HSP90β plays important roles in Ni2+-induced production of IL-8 and could be a potential target for the regulation of Ni2+-induced inflammation.
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Affiliation(s)
- Sanki Asakawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Ryo Onodera
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Koji Kasai
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Yu Kishimoto
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Taiki Sato
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Ryosuke Segawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Natsumi Mizuno
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Kouetsu Ogasawara
- Department of Immunobiology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi, Japan
| | - Takahiro Moriya
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Masahiro Hiratsuka
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Noriyasu Hirasawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan.
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17
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Vibrio cholerae OmpU induces IL-8 expression in human intestinal epithelial cells. Mol Immunol 2017; 93:47-54. [PMID: 29145158 DOI: 10.1016/j.molimm.2017.11.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 11/05/2017] [Accepted: 11/07/2017] [Indexed: 01/22/2023]
Abstract
Although Vibrio cholerae colonizes the small intestine and induces acute inflammatory responses, less is known about the molecular mechanisms of V. cholerae-induced inflammatory responses in the intestine. We recently reported that OmpU, one of the most abundant outer membrane proteins of V. cholerae, plays an important role in the innate immunity of the whole bacteria. In this study, we evaluated the role of OmpU in induction of IL-8, a representative chemokine that recruits various inflammatory immune cells, in the human intestinal epithelial cell (IEC) line, HT-29. Recombinant OmpU (rOmpU) of V. cholerae induced IL-8 expression at the mRNA and protein levels in a dose- and time-dependent manner. Interestingly, IL-8 was secreted through both apical and basolateral sides of the polarized HT-29 cells upon apical exposure to rOmpU but not upon basolateral exposure. rOmpU-induced IL-8 expression was inhibited by interference of lipid raft formation with nystatin, but not by blocking the formation of clathrin-coated pits with chlorpromazine. In addition, rOmpU-induced IL-8 expression was mediated via ERK1/2 and p38 kinase pathways, but not via JNK signaling pathway. Finally, V. cholerae lacking ompU elicited decreased IL-8 expression and adherence to HT-29 cells compared to the parental strain. Collectively, these results suggest that V. cholerae OmpU might play an important role in intestinal inflammation by inducing IL-8 expression in human IECs.
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18
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Osei-Adjei G, Gao H, Zhang Y, Zhang L, Yang W, Yang H, Yin Z, Huang X, Zhang Y, Zhou D. Regulatory actions of ToxR and CalR on their own genes and type III secretion system 1 in Vibrio parahaemolyticus. Oncotarget 2017; 8:65809-65822. [PMID: 29029474 PMCID: PMC5630374 DOI: 10.18632/oncotarget.19498] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 06/20/2017] [Indexed: 12/11/2022] Open
Abstract
Vibrio parahaemolyticus is the leading cause of seafood-associated gastroenteritis. Type III secretion system 1 (T3SS1) is one of the virulence determinants of this bacteria. T3SS1 expression is regulated by ToxR and CalR. ToxR represses the transcription of T3SS1 genes via activation of CalR, which acts as a transcriptional repressor of T3SS1 genes. However, the transcriptional regulation mechanisms have not been elucidated. As showing in the present work, ToxR binds to the promoter DNA region of calR to activate its transcription. CalR occupies the promoter-proximal regions of each detected target operons in T3SS1 loci to repress their transcription, and thereby inhibiting T3SS1-dependent cytotoxicity. Moreover, a feedback CalR inhibits toxR and its own gene in a direct manner. Collectively, this work reported an interesting gene regulatory network involving the reciprocal regulation of ToxR and CalR, and their regulation on T3SS1 genes transcription in V. parahaemolyticus.
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Affiliation(s)
| | - He Gao
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Ying Zhang
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - Lingyu Zhang
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - Wenhui Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Huiying Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Zhe Yin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Xinxiang Huang
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - Yiquan Zhang
- School of Medicine, Jiangsu University, Zhenjiang 212013, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
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De Nisco NJ, Kanchwala M, Li P, Fernandez J, Xing C, Orth K. The cytotoxic type 3 secretion system 1 of Vibrio rewires host gene expression to subvert cell death and activate cell survival pathways. Sci Signal 2017; 10:10/479/eaal4501. [PMID: 28512145 DOI: 10.1126/scisignal.aal4501] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Bacterial effectors potently manipulate host signaling pathways. The marine bacterium Vibrio parahaemolyticus (V. para) delivers effectors into host cells through two type 3 secretion systems (T3SSs). T3SS1 is vital for V. para survival in the environment, whereas T3SS2 causes acute gastroenteritis in human hosts. Although the natural host is undefined, T3SS1 effectors attack highly conserved cellular processes and pathways to orchestrate nonapoptotic cell death. To understand how the concerted action of T3SS1 effectors globally affects host cell signaling, we compared gene expression changes over time in primary fibroblasts infected with V. para that have a functional T3SS1 (T3SS1+) to those in cells infected with V. para lacking T3SS1 (T3SS1-). Overall, the host transcriptional response to both T3SS1+ and T3SS1-V. para was rapid, robust, and temporally dynamic. T3SS1 rewired host gene expression by specifically altering the expression of 398 genes. Although T3SS1 effectors targeted host cells at the posttranslational level to cause cytotoxicity, V. para T3SS1 also precipitated a host transcriptional response that initially activated cell survival and repressed cell death networks. The increased expression of several key prosurvival transcripts mediated by T3SS1 depended on a host signaling pathway that is silenced posttranslationally later in infection. Together, our analysis reveals a complex interplay between the roles of T3SS1 as both a transcriptional and posttranslational manipulator of host cell signaling.
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Affiliation(s)
- Nicole J De Nisco
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mohammed Kanchwala
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Peng Li
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jessie Fernandez
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Chao Xing
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. .,Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Ghenem L, Elhadi N, Alzahrani F, Nishibuchi M. Vibrio Parahaemolyticus: A Review on Distribution, Pathogenesis, Virulence Determinants and Epidemiology. SAUDI JOURNAL OF MEDICINE & MEDICAL SCIENCES 2017; 5:93-103. [PMID: 30787765 PMCID: PMC6298368 DOI: 10.4103/sjmms.sjmms_30_17] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vibrio parahaemolyticus is a Gram-negative, halophilic bacterium isolated from marine environments globally. After the consumption of contaminated seafood, V. parahaemolyticus causes acute gastroenteritis. To initiate infection, a wide range of virulence factors are required. A complex group of genes is known to participate in the pathogenicity of V. parahaemolyticus; however, to understand the full mechanism of infection, extensive research is yet required. V. parahaemolyticus has become the leading cause of seafood-related gastroenteritis in Japan, the United States and several other parts of the world. In addition, outbreaks caused by the pandemic clone of this organism are escalating and spreading universally. To minimize the risk of V. parahaemolyticus infection and warrant the safety of seafood, collaboration between governments and scientists is required. We herein provide an updated review of the pathogenicity determinants and distribution of V. parahaemolyticus to deliver a better understanding of the significance of V. parahaemolyticus and its host-pathogen interactions.
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Affiliation(s)
- Lubna Ghenem
- Department of Clinical Laboratory Science, College of Applied Medical Sciences, University of Dammam, 31441 Dammam, Kingdom of Saudi Arabia
| | - Nasreldin Elhadi
- Department of Clinical Laboratory Science, College of Applied Medical Sciences, University of Dammam, 31441 Dammam, Kingdom of Saudi Arabia
| | - Faisal Alzahrani
- Department of Clinical Laboratory Science, College of Applied Medical Sciences, University of Dammam, 31441 Dammam, Kingdom of Saudi Arabia
| | - Mitsuaki Nishibuchi
- Center for Southeast Asian Studies, Kyoto University, 46 Shomoadachi-cho, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
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Wang Y, Li H, Li D, Li K, Wang Y, Xu J, Ye C. Multiple Cross Displacement Amplification Combined with Gold Nanoparticle-Based Lateral Flow Biosensor for Detection of Vibrio parahaemolyticus. Front Microbiol 2016; 7:2047. [PMID: 28066368 PMCID: PMC5177632 DOI: 10.3389/fmicb.2016.02047] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 12/06/2016] [Indexed: 12/21/2022] Open
Abstract
Vibrio parahaemolyticus (V. parahaemolyticus) is a marine seafood-borne pathogen causing severe illnesses in humans and aquatic animals. In the present study, multiple cross displacement amplification was combined with a lateral flow biosensor (MCDA-LFB) to detect the toxR gene of V. parahaemolyticus in DNA extracts from pure cultures and spiked oyster homogenates. Amplification was carried out at a constant temperature (62°C) for only 30 min, and amplification products were directly applied to the biosensor. The entire process, including oyster homogenate processing (30 min), isothermal amplification (30 min) and results indicating (∼2 min), could be completed within 65 min. Amplification product was detectable from as little as 10 fg of pure V. parahaemolyticus DNA and from approximately 4.2 × 102 CFU in 1 mL of oyster homogenate. No cross-reaction with other Vibrio species and with non-Vibrio species was observed. Therefore, the MCDA-LFB method established in the current report is suitable for the rapid screening of V. parahaemolyticus in clinical, food, and environmental samples.
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Affiliation(s)
- Yi Wang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention Beijing, China
| | - Hui Li
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and PreventionBeijing, China; Department of Microbiology, Guizhou Medical UniversityGuiyang, China
| | - Dongxun Li
- Changping District Center for Disease Control and Prevention Beijing, China
| | - Kewei Li
- Institute of Microbiology, Jilin Provincial Center for Disease Control and Prevention Changchun, China
| | - Yan Wang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention Beijing, China
| | - Jianguo Xu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention Beijing, China
| | - Changyun Ye
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention Beijing, China
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DNA-Binding Protein HU Coordinates Pathogenicity in Vibrio parahaemolyticus. J Bacteriol 2015; 197:2958-64. [PMID: 26148713 DOI: 10.1128/jb.00306-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/28/2015] [Indexed: 01/07/2023] Open
Abstract
UNLABELLED HU is one of the most abundant nucleoid-associated proteins in bacterial cells and regulates the expression of many genes involved in growth, motility, metabolism, and virulence. It is known that Vibrio parahaemolyticus pathogenicity is related to its characteristic rapid growth and that type III secretion system 1 (T3SS1) contributes to its cytotoxicity. However, it is not known if HU plays a role in the pathogenicity of V. parahaemolyticus. In the present study, we investigated the effect of HU proteins HU-2 (HUα) (V. parahaemolyticus 2911 [vp2911]) and HUβ (vp0920) on the pathogenicity of V. parahaemolyticus. We found that a deletion of both HU subunits (yielding the ΔHUs [Δvp0920 Δvp2911] strain), but not single deletions, led to a reduction of the growth rate. In addition, expression levels of T3SS1-related genes, including exsA (positive regulator), exsD (negative regulator), vp1680 (cytotoxic effector), and vp1671 (T3SS1 apparatus), were reduced in the ΔHUs strain compared to the wild type (WT). As a result, cytotoxicity to HeLa cells was decreased in the ΔHUs strain. The additional deletion of exsD in the ΔHUs strain restored T3SS1-related gene expression levels and cytotoxicity but not the growth rate. These results suggest that the HU protein regulates the levels of T3SS1 gene expression and cytotoxicity in a growth rate-independent manner. IMPORTANCE Nucleoid-binding protein HU regulates cellular behaviors, including nucleoid structuring, general recombination, transposition, growth, replication, motility, metabolism, and virulence. It is thought that both the number of bacteria and the number of virulence factors may affect the pathogenicity of bacteria. In the present study, we investigated which factor(s) has a dominant role during infection in one of the most rapidly growing bacterial species, Vibrio parahaemolyticus. We found that V. parahaemolyticus cytotoxicity is regulated, in a growth rate-independent manner, by the HU proteins through regulation of a number of virulence factors, including T3SS1 gene expression.
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Wang R, Zhong Y, Gu X, Yuan J, Saeed AF, Wang S. The pathogenesis, detection, and prevention of Vibrio parahaemolyticus. Front Microbiol 2015; 6:144. [PMID: 25798132 PMCID: PMC4350439 DOI: 10.3389/fmicb.2015.00144] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 02/07/2015] [Indexed: 12/02/2022] Open
Abstract
Vibrio parahaemolyticus, a Gram-negative motile bacterium that inhabits marine and estuarine environments throughout the world, is a major food-borne pathogen that causes life-threatening diseases in humans after the consumption of raw or undercooked seafood. The global occurrence of V. parahaemolyticus accentuates the importance of investigating its virulence factors and their effects on the human host. This review describes the virulence factors of V. parahaemolyticus reported to date, including hemolysin, urease, two type III secretion systems and two type VI secretion systems, which both cause both cytotoxicity in cultured cells and enterotoxicity in animal models. We describe various types of detection methods, based on virulence factors, that are used for quantitative detection of V. parahaemolyticus in seafood. We also discuss some useful preventive measures and therapeutic strategies for the diseases mediated by V. parahaemolyticus, which can reduce, to some extent, the damage to humans and aquatic animals attributable to V. parahaemolyticus. This review extends our understanding of the pathogenic mechanisms of V. parahaemolyticus mediated by virulence factors and the diseases it causes in its human host. It should provide new insights for the diagnosis, treatment, and prevention of V. parahaemolyticus infection.
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Affiliation(s)
- Rongzhi Wang
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Yanfang Zhong
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Xiaosong Gu
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Jun Yuan
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Abdullah F Saeed
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Shihua Wang
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
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O'Boyle N, Boyd A. Manipulation of intestinal epithelial cell function by the cell contact-dependent type III secretion systems of Vibrio parahaemolyticus. Front Cell Infect Microbiol 2014; 3:114. [PMID: 24455490 PMCID: PMC3887276 DOI: 10.3389/fcimb.2013.00114] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 12/21/2013] [Indexed: 12/23/2022] Open
Abstract
Vibrio parahaemolyticus elicits gastroenteritis by deploying Type III Secretion Systems (TTSS) to deliver effector proteins into epithelial cells of the human intestinal tract. The bacteria must adhere to the human cells to allow colonization and operation of the TTSS translocation apparatus bridging the bacterium and the host cell. This article first reviews recent advances in identifying the molecules responsible for intercellular adherence. V. parahaemolyticus possesses two TTSS, each of which delivers an exclusive set of effectors and mediates unique effects on the host cell. TTSS effectors primarily target and alter the activation status of host cell signaling proteins, thereby bringing about changes in the regulation of cellular behavior. TTSS1 is responsible for the cytotoxicity of V. parahaemolyticus, while TTSS2 is necessary for the enterotoxicity of the pathogen. Recent publications have elucidated the function of several TTSS effectors and their importance in the virulence of the bacterium. This review will explore the ability of the TTSS to manipulate activities of human intestinal cells and how this modification of cell function favors bacterial colonization and persistence of V. parahaemolyticus in the host.
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Affiliation(s)
- Nicky O'Boyle
- Pathogenic Mechanisms Research Group, Microbiology, School of Natural Sciences, National University of Ireland Galway Galway, Ireland
| | - Aoife Boyd
- Pathogenic Mechanisms Research Group, Microbiology, School of Natural Sciences, National University of Ireland Galway Galway, Ireland
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The MSHA pilus of Vibrio parahaemolyticus has lectin functionality and enables TTSS-mediated pathogenicity. Int J Med Microbiol 2013; 303:563-73. [DOI: 10.1016/j.ijmm.2013.07.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 07/24/2013] [Accepted: 07/29/2013] [Indexed: 01/15/2023] Open
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Vibrio effector protein, VopQ, forms a lysosomal gated channel that disrupts host ion homeostasis and autophagic flux. Proc Natl Acad Sci U S A 2013; 110:11559-64. [PMID: 23798441 DOI: 10.1073/pnas.1307032110] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Defects in normal autophagic pathways are implicated in numerous human diseases--such as neurodegenerative diseases, cancer, and cardiomyopathy--highlighting the importance of autophagy and its proper regulation. Herein we show that Vibrio parahaemolyticus uses the type III effector VopQ (Vibrio outer protein Q) to alter autophagic flux by manipulating the partitioning of small molecules and ions in the lysosome. This effector binds to the conserved Vo domain of the vacuolar-type H(+)-ATPase and causes deacidification of the lysosomes within minutes of entering the host cell. VopQ forms a gated channel ∼18 Å in diameter that facilitates outward flux of ions across lipid bilayers. The electrostatic interactions of this type 3 secretion system effector with target membranes dictate its preference for host vacuolar-type H(+)-ATPase-containing membranes, indicating that its pore-forming activity is specific and not promiscuous. As seen with other effectors, VopQ is exploiting a eukaryotic mechanism, in this case manipulating lysosomal homeostasis and autophagic flux through transmembrane permeation.
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Zhang L, Orth K. Virulence determinants for Vibrio parahaemolyticus infection. Curr Opin Microbiol 2013; 16:70-7. [PMID: 23433802 DOI: 10.1016/j.mib.2013.02.002] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 01/22/2013] [Accepted: 02/03/2013] [Indexed: 12/31/2022]
Abstract
Vibrio parahaemolyticus is a marine microorganism that causes acute gastroenteritis associated with the consumption of contaminated raw or under cooked seafood. During infection, the bacterium utilizes a wide variety of virulence factors, including adhesins, toxins and type III secretion systems, to cause both cytotoxicity in cultured cells and enterotoxicity in animal models. Herein, we describe recent discoveries on the regulation and characterization of the virulence factors from V. para. Determining how this bacterial pathogen uses virulence factors to mediate pathogenicity improves our understanding of V. para. infections and more generally, host-pathogen interactions.
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Affiliation(s)
- Lingling Zhang
- Department of Molecular Biology, Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390, USA
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Genetic diversity of clinical and environmental Vibrio parahaemolyticus strains from the Pacific Northwest. Appl Environ Microbiol 2012; 78:8631-8. [PMID: 23042162 DOI: 10.1128/aem.01531-12] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Since 1997, cases of Vibrio parahaemolyticus-related gastroenteritis from the consumption of raw oysters harvested in Washington State have been higher than historical levels. These cases have shown little or no correlation with concentrations of potentially pathogenic V. parahaemolyticus (positive for the thermostable direct hemolysin gene, tdh) in oysters, although significant concentrations of tdh(+) V. parahaemolyticus strains were isolated from shellfish-growing areas in the Pacific Northwest (PNW). We compared clinical and environmental strains isolated from the PNW to those from other geographic regions within the United States and Asia for the presence of virulence-associated genes, including the thermostable direct hemolysin (tdh), the thermostable-related hemolysin (trh), urease (ureR), the pandemic group specific markers orf8 and toxRS, and genes encoding both type 3 secretion systems (T3SS1 and T3SS2). The majority of clinical strains from the PNW were positive for tdh, trh, and ureR genes, while a significant proportion of environmental isolates were tdh(+) but trh negative. Hierarchical clustering grouped the majority of these clinical isolates into a cluster distinct from that including the pandemic strain RIMD2210633, clinical isolates from other geographical regions, and tdh(+), trh-negative environmental isolates from the PNW. We detected T3SS2-related genes (T3SS2β) in environmental strains that were tdh and trh negative. The presence of significant concentrations of tdh(+), trh-negative environmental strains in the PNW that have not been responsible for illness and T3SS2β in tdh- and trh-negative strains emphasizes the diversity in this species and the need to identify additional virulence markers for this bacterium to improve risk assessment tools for the detection of this pathogen.
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Clostridium perfringens alpha-toxin induces the release of IL-8 through a dual pathway via TrkA in A549 cells. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1581-9. [DOI: 10.1016/j.bbadis.2012.06.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/08/2012] [Accepted: 06/12/2012] [Indexed: 12/27/2022]
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Shimohata T, Mawatari K, Iba H, Hamano M, Negoro S, Asada S, Aihara M, Hirata A, Su Z, Takahashi A. VopB1 and VopD1 are essential for translocation of type III secretion system 1 effectors of Vibrio parahaemolyticus. Can J Microbiol 2012; 58:1002-7. [PMID: 22827847 DOI: 10.1139/w2012-081] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Vibrio parahaemolyticus is a pathogenic Vibrio species that causes food-borne acute gastroenteritis, often related to the consumption of raw or undercooked seafood. Vibrio parahaemolyticus has 2 type III secretion systems (T3SS1 and T3SS2). Here, we demonstrate that VP1657 (VopB1) and VP1656 (VopD1), which share sequence similarity with Pseudomonas genes popB (38%) and popD (36%), respectively, are essential for translocation of T3SS1 effectors into host cells. A VP1680CyaA fusion reporter system was constructed to observe effector translocation. Using this reporter assay we showed that the VopB1 and VopD1 deletion strains were unable to translocate VP1680 to host cell but that the secretion of VP1680 into the culture medium was not affected. VopB1 or VopD1 deletion strains did not enhance cytotoxicity and failed to activate mitogen-activated protein kinases and secretion of interleukin-8, which depend on VP1680. Thus, we conclude that VopB1 and VopD1 are essential components of the translocon. To target VopB1 and VopD1 may have therapeutic potential for the treatment or prevention in V. parahaemolyticus infection.
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Affiliation(s)
- Takaaki Shimohata
- Department of Preventive Environment and Nutrition Institute of Health Biosciences, University of Tokushima Graduate School Kuromoto-cho 3-18-15, Tokushima City, Tokushima 770-8503, Japan.
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Matsuda S, Okada N, Kodama T, Honda T, Iida T. A cytotoxic type III secretion effector of Vibrio parahaemolyticus targets vacuolar H+-ATPase subunit c and ruptures host cell lysosomes. PLoS Pathog 2012; 8:e1002803. [PMID: 22829766 PMCID: PMC3400558 DOI: 10.1371/journal.ppat.1002803] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 06/01/2012] [Indexed: 12/20/2022] Open
Abstract
Vibrio parahaemolyticus is one of the human pathogenic vibrios. During the infection of mammalian cells, this pathogen exhibits cytotoxicity that is dependent on its type III secretion system (T3SS1). VepA, an effector protein secreted via the T3SS1, plays a major role in the T3SS1-dependent cytotoxicity of V. parahaemolyticus. However, the mechanism by which VepA is involved in T3SS1-dependent cytotoxicity is unknown. Here, we found that protein transfection of VepA into HeLa cells resulted in cell death, indicating that VepA alone is cytotoxic. The ectopic expression of VepA in yeast Saccharomyces cerevisiae interferes with yeast growth, indicating that VepA is also toxic in yeast. A yeast genome-wide screen identified the yeast gene VMA3 as essential for the growth inhibition of yeast by VepA. Although VMA3 encodes subunit c of the vacuolar H+-ATPase (V-ATPase), the toxicity of VepA was independent of the function of V-ATPases. In HeLa cells, knockdown of V-ATPase subunit c decreased VepA-mediated cytotoxicity. We also demonstrated that VepA interacted with V-ATPase subunit c, whereas a carboxyl-terminally truncated mutant of VepA (VepAΔC), which does not show toxicity, did not. During infection, lysosomal contents leaked into the cytosol, revealing that lysosomal membrane permeabilization occurred prior to cell lysis. In a cell-free system, VepA was sufficient to induce the release of cathepsin D from isolated lysosomes. Therefore, our data suggest that the bacterial effector VepA targets subunit c of V-ATPase and induces the rupture of host cell lysosomes and subsequent cell death. Vibrio parahaemolyticus is a bacterial pathogen that causes food-borne gastroenteritis and also wound infection and septicemia. It exhibits cytotoxicity that is dependent on its type III secretion system (T3SS1) during the infection of mammalian cells. Although an effector VepA plays a major role in the cytotoxicity, the mechanism was unknown. Here we show that VepA targets subunit c of the vacuolar H+-ATPase (V-ATPase) and induces the rupture of host cell lysosomes. We found that VepA alone is cytotoxic in HeLa cells and also toxic in yeast Saccharomyces cerevisiae. Using a yeast genome-wide screening, we identified yeast V-ATPase subunit c as essential for the toxicity of VepA to yeast. We also demonstrated that knockdown of V-ATPase subunit c decreased VepA-mediated cytotoxicity toward HeLa cells and that VepA interacted with subunit c of V-ATPase. During infection, lysosomal contents leaked into the cytosol prior to cell lysis, and VepA was necessary and sufficient for this leakage. Our data suggest that a bacterial effector VepA ruptures lysosomes, the “suicide bags” of host cells, by targeting the evolutionarily conserved V-ATPase, and elicits subsequent cell death.
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Affiliation(s)
- Shigeaki Matsuda
- Laboratory of Genomic Research on Pathogenic Bacteria, International Research Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
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Paracoccidioides brasiliensis induces secretion of IL-6 and IL-8 by lung epithelial cells. Modulation of host cytokine levels by fungal proteases. Microbes Infect 2012; 14:1077-85. [PMID: 22687715 DOI: 10.1016/j.micinf.2012.05.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 05/24/2012] [Accepted: 05/25/2012] [Indexed: 11/21/2022]
Abstract
Paracoccidioides brasiliensis is a pathogenic, dimorphic fungus that causes paracoccidioidomycosis, a systemic human mycosis that is highly prevalent in Latin America. In this study, we demonstrated that P. brasiliensis yeasts induced interleukin (IL)-8 and IL-6 secretion by human lung epithelial A549 cells. However, tumor necrosis factor-α and interferon-γ were undetectable in these cultures. Moreover, P. brasiliensis yeasts induced activation of p38 mitogen-activated protein kinase (MAPK), c-Jun NH(2)-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) 1/2 in A549 cells, and IL-8 and IL-6 secretion promoted by this fungus was dependent on activation of p38 MAPK and ERK 1/2. In addition, IL-8 and IL-6 levels were significantly higher in culture supernatants of A549 cells that were incubated with formaldehyde-fixed P. brasiliensis compared to cultures of cells that were infected with live yeasts. Our results indicate that the observed cytokine level differences were due to protease expression, in live yeasts, that degraded these cytokines. Degradation of human recombinant IL-8 and IL-6 by live P. brasiliensis was inhibited by AEBSF and aprotinin, suggesting that these proteases belong to a family of serine proteases. This is the first report showing that P. brasiliensis may modulate host inflammation by expressing proteases that degrade proinflammatory cytokines.
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Rahman MA, Cheng Z, Matsuo J, Rikihisa Y. Penicillin-binding protein of Ehrlichia chaffeensis: cytokine induction through MyD88-dependent pathway. J Infect Dis 2012; 206:110-6. [PMID: 22539814 DOI: 10.1093/infdis/jis313] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Human monocytic ehrlichiosis is one of the most prevalent tick-borne zoonoses caused by infection with Ehrlichia chaffeensis. Although E. chaffeensis lacks entire lipopolysaccharide and most peptidoglycan biosynthesis genes, it induces inflammatory cytokines and chemokines. Ehrlichia chaffeensis components that induce inflammation and the responsive host cell pathway are not known. METHODS Expression of penicillin-binding protein (PBP) in E. chaffeensis was analyzed by reverse-transcription polymerase chain reaction and Bocillin FL binding assay. Next, recombinant PBP, which was high-pressure liquid chromatography purified, and native PBP of E. chaffeensis were investigated for their ability to induce proinflammatory cytokines in the human monocytic leukemia cell line THP-1 and bone marrow-derived macrophages (BMDMs) from wild-type and MyD88 knockout mice. RESULTS Expression of PBP by E. chaffeensis was upregulated during its intracellular life cycle. PBP induced interleukin 8 or CXCL2, tumor necrosis factor α, interleukin 1β, and interleukin 10 in THP-1 cells and BMDMs. Cytokine induction by PBP was MyD88-dependent. Removal of PBP from E. chaffeensis lysate using penicillin affinity column and a complementation assay confirmed cytokine-inducing activity of native PBP. CONCLUSIONS The cytokine-inducing activity by E. chaffeensis PBP provides novel insights into pathogen-associated molecular patterns and pathogenesis of E. chaffeensis infection.
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Affiliation(s)
- Mohd Akhlakur Rahman
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210-1093, USA
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The Vibrio parahaemolyticus ToxRS regulator is required for stress tolerance and colonization in a novel orogastric streptomycin-induced adult murine model. Infect Immun 2012; 80:1834-45. [PMID: 22392925 DOI: 10.1128/iai.06284-11] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Vibrio parahaemolyticus, a marine bacterium, is the causative agent of gastroenteritis associated with the consumption of seafood. It contains a homologue of the toxRS operon that in V. cholerae is the key regulator of virulence gene expression. We examined a nonpolar mutation in toxRS to determine the role of these genes in V. parahaemolyticus RIMD2210633, an O3:K6 isolate, and showed that compared to the wild type, ΔtoxRS was significantly more sensitive to acid, bile salts, and sodium dodecyl sulfate stresses. We demonstrated that ToxRS is a positive regulator of ompU expression, and that the complementation of ΔtoxRS with ompU restores stress tolerance. Furthermore, we showed that ToxRS also regulates type III secretion system genes in chromosome I via the regulation of the leuO homologue VP0350. We examined the effect of ΔtoxRS in vivo using a new orogastric adult murine model of colonization. We demonstrated that streptomycin-treated adult C57BL/6 mice experienced prolonged intestinal colonization along the entire intestinal tract by the streptomycin-resistant V. parahaemolyticus. In contrast, no colonization occurred in non-streptomycin-treated mice. A competition assay between the ΔtoxRS and wild-type V. parahaemolyticus strains marked with the β-galactosidase gene lacZ demonstrated that the ΔtoxRS strain was defective in colonization compared to the wild-type strain. This defect was rescued by ectopically expressing ompU. Thus, the defect in stress tolerance and colonization in ΔtoxRS is solely due to OmpU. To our knowledge, the orogastric adult murine model reported here is the first showing sustained intestinal colonization by V. parahaemolyticus.
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Broberg CA, Calder TJ, Orth K. Vibrio parahaemolyticus cell biology and pathogenicity determinants. Microbes Infect 2011; 13:992-1001. [PMID: 21782964 PMCID: PMC3384537 DOI: 10.1016/j.micinf.2011.06.013] [Citation(s) in RCA: 247] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 06/15/2011] [Accepted: 06/17/2011] [Indexed: 10/18/2022]
Abstract
Vibrio parahaemolyticus is a significant cause of gastroenteritis worldwide. Characterization of this pathogen has revealed a unique repertoire of virulence factors that allow for colonization of the human host and disease. The following describes the known pathogenicity determinants while establishing the need for continued research.
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Affiliation(s)
- Christopher A. Broberg
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas TX 75390-9148, USA
| | - Thomas J. Calder
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas TX 75390-9148, USA
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas TX 75390-9148, USA
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Ehrlichia chaffeensis induces monocyte inflammatory responses through MyD88, ERK, and NF-κB but not through TRIF, interleukin-1 receptor 1 (IL-1R1)/IL-18R1, or toll-like receptors. Infect Immun 2011; 79:4947-56. [PMID: 21930764 DOI: 10.1128/iai.05640-11] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Human monocytic ehrlichiosis, an influenza-like illness accompanied by signs of hepatitis, is caused by infection of monocytes/macrophages with a lipopolysaccharide-deficient bacterium, Ehrlichia chaffeensis. The E. chaffeensis strain Wakulla induces diffuse hepatitis with neutrophil infiltration in mice with severe combined immunodeficiency, which is accompanied by strong CXCL2 (mouse functional homolog of interleukin-8 [IL-8]) and tumor necrosis factor alpha (TNF-α) expression in the liver. In this study, we found that expression of IL-1β, CXCL2, and TNF-α was induced by strain Wakulla in mouse bone marrow-derived macrophages; this expression was dependent on MyD88, but not on TRIF, TLR2/4, IL-1R1/IL-18R1, or endosome acidification. When the human leukemia cell line THP-1 was exposed to E. chaffeensis, significant upregulation of IL-8, IL-1β, and TNF-α mRNA and extracellular regulated kinase 2 (ERK2) activation were detected. U0126 (inhibitor of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1/2 [MEK1/2] upstream of ERK), manumycin A (Ras inhibitor), BAY43-9006 (Raf-1 inhibitor), and NS-50 (inhibitor of NF-κB nuclear translocation) inhibited the cytokine gene expression. A luciferase reporter assay using HEK293 cells, which lack Toll-like receptors (TLRs), showed activation of both the IL-8 promoter and NF-κB by E. chaffeensis. Activation of the IL-8 promoter in transfected HEK293 cells was inhibited by manumycin A, BAY43-9006, U0126, and transfection with a dominant-negative Ras mutant. These results indicate that the E. chaffeensis Wakulla strain can induce inflammatory responses through MyD88-dependent NF-κB and ERK pathways, without the involvement of TRIF and TLRs.
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