Autophagy is induced by the type III secretion system of Vibrio alginolyticus in several mammalian cell lines

Zhao, Zhe; Zhang, Lvping; Ren, Chen; Zhao, Jingjing; Chen, Chang; Jiang, Xiao; Luo, Peng; Hu, Chaoqun

doi:10.1007/s00203-010-0646-9

Cited by 26 publications

(22 citation statements)

References 32 publications

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“…In V. alginolyticus, a V. harveyi-like QS signaling system has been characterized, which involved pivotal LuxO and LuxR regulators (16)(17)(18)(19)(20)(21)(22)29). AphA has been reported as another master regulator of QS in V. harveyi, V. cholerae, and V. parahaemolyticus (3,4,34).…”

Section: Discussionmentioning

confidence: 99%

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Chromatin Immunoprecipitation Sequencing Technology Reveals Global Regulatory Roles of Low-Cell-Density Quorum-Sensing Regulator AphA in the Pathogen Vibrio alginolyticus

Liu

Yang

et al. 2016

J Bacteriol

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Quorum sensing (QS) is an important regulatory system in virulence expression and environmental adaptation in bacteria. The master QS regulators (MQSR) LuxR and AphA reciprocally control QS gene expression in vibrios. However, the molecular basis for the regulatory functions of AphA remains undefined. In this study, we characterized its regulatory roles in Vibrio alginolyticus, an important zoonotic pathogen causing diseases in marine animals as well as in humans. AphA is involved in the motility ability, biofilm formation, and in vivo survival of V. alginolyticus. Specifically, AphA is expressed at low-cell-density growth phases. In addition, AphA negatively regulates the expression of the main virulence factor, alkaline serine protease (Asp), through LuxR. Chromatin immunoprecipitation (ChIP) followed by high-throughput DNA sequencing (ChIP-seq) detected 49 enriched loci harboring AphA-binding peaks across the V. alginolyticus genome. An AphA-specific binding motif was identified and further confirmed by electrophoretic mobility shift assay (EMSA) and mutagenesis analysis. A quantitative real-time PCR (qRT-PCR) assay further validated the regulation of AphA on these genes. AphA binds directly to the aphA promoter and negatively regulates its own expression. Moreover, AphA directly regulates genes encoding adenylate cyclase, anti-D , FabR, and the small RNA CsrB, revealing versatile regulatory roles of AphA in its physiology and virulence. Furthermore, our data indicated that AphA modulates motility through the coordinated function of LuxR and CsrB. Collectively, the findings of this work contribute to better understanding of the regulatory roles of AphA in QS and non-QS genes. IMPORTANCEIn this work, we determined that AphA, the master regulator of QS at low cell density, plays essential roles in expression of genes associated with physiology and virulence in V. alginolyticus, a Gram-negative pathogen for humans and marine animals. We further uncovered that 49 genes could be directly regulated by AphA and a 19-bp consensus binding sequence was identified. Among the 49 genes, the QS and other non-QS-associated genes were identified to be regulated by AphA. Besides, the small RNA CsrB was negatively regulated by AphA, and AphA regulate motility abilities through both CsrB and LuxR. Taken together, the findings of this study improve our understanding of the complex regulation network of AphA and QS. B acteria are highly social organisms capable of sophisticated cooperative behaviors mediated by the quorum-sensing (QS) system, a cell density-dependent signaling circuit (1). In Vibrio harveyi, there are three well-defined QS signaling molecules, known as autoinduers (AIs), including acylated homoserine lactones (HAI-1), furanosyl borate diester (AI-2), and CAI-1 (2). The membrane sensors LuxN, LuxQ, and CqsS can detect their cognate AIs and transduce the signals required to trigger gene expression through phospho-relay cascades (2). At low cell densities (LCDs; low AI concentrations), phosphates are directe...

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Section: Discussionmentioning

confidence: 99%

“…The major virulence factors of V. alginolyticus are extracellular proteases, motility, siderophore-dependent iron uptake systems, biofilm, type III secretion systems (T3SS), and type VI secretion systems (T6SS) (16)(17)(18)(19)(20)(21)(22). These factors and some other virulence-related genes are closely regulated by the QS system in V. alginolyticus.…”

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confidence: 99%

Chromatin Immunoprecipitation Sequencing Technology Reveals Global Regulatory Roles of Low-Cell-Density Quorum-Sensing Regulator AphA in the Pathogen Vibrio alginolyticus

Liu

Yang

et al. 2016

J Bacteriol

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“…Among the vibrios, V. alginolyticus , V. harveyi and V. tubiashii possess T3SSs that are highly homologous to V. parahaemolyticus T3SS1 [8]. The V. alginolyticus T3SS exhibits cytotoxicity in mammalian and fish cells [33], [34]. Because VepA is also conserved among these species, it is possible that VepA homologs are involved in the cytotoxicity of other Vibrio species.…”

Section: Discussionmentioning

confidence: 99%

A Cytotoxic Type III Secretion Effector of Vibrio parahaemolyticus Targets Vacuolar H+-ATPase Subunit c and Ruptures Host Cell Lysosomes

et al. 2012

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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.

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“…V. alginolyticus is prevalent in coastal waters of southern China and it is commonly associated with costly disease of aquatic animals (Austin, 2010). Previous studies demonstrated that V. alginolyticus induces apoptosis, cell rounding and osmotic lysis in fish cells and autophagy in mammalian cell lines in a T3SS-dependent manner (Zhao et al, 2010, 2011). Although the T3SS of V. alginolyticus is similar to T3SS1 of V. parahaemolyticus with respect to gene synteny (Zhao et al, 2010), it is unclear if the same regulatory mechanism is employed by V. alginolyticus .…”

Section: Introductionmentioning

confidence: 98%

ExsE Is a Negative Regulator for T3SS Gene Expression in Vibrio alginolyticus

Liu

Orfe

et al. 2016

Front. Cell. Infect. Microbiol.

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Type III secretion systems (T3SSs) contribute to microbial pathogenesis of Vibrio species, but the regulatory mechanisms are complex. We determined if the classic ExsACDE protein-protein regulatory model from Pseudomonas aeruginosa applies to Vibrio alginolyticus. Deletion mutants in V. alginolyticus demonstrated that, as expected, the T3SS is positively regulated by ExsA and ExsC and negatively regulated by ExsD and ExsE. Interestingly, deletion of exsE enhanced the ability of V. alginolyticus to induce host-cell death while cytotoxicity was inhibited by in trans complementation of this gene in a wild-type strain, a result that differs from a similar experiment with Vibrio parahaemolyticus ExsE. We further showed that ExsE is a secreted protein that does not contribute to adhesion to Fathead minnow epithelial cells. An in vitro co-immunoprecipitation assay confirmed that ExsE binds to ExsC to exert negative regulatory effect on T3SS genes. T3SS in V. alginolyticus can be activated in the absence of physical contact with host cells and a separate regulatory pathway appears to contribute to the regulation of ExsA. Consequently, like ExsE from P. aeruginosa, ExsE is a negative regulator for T3SS gene expression in V. alginolyticus. Unlike the V. parahaemolyticus orthologue, however, deletion of exsE from V. alginolyticus enhanced in vitro cytotoxicity.

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Autophagy is induced by the type III secretion system of Vibrio alginolyticus in several mammalian cell lines

Cited by 26 publications

References 32 publications

Chromatin Immunoprecipitation Sequencing Technology Reveals Global Regulatory Roles of Low-Cell-Density Quorum-Sensing Regulator AphA in the Pathogen Vibrio alginolyticus

Chromatin Immunoprecipitation Sequencing Technology Reveals Global Regulatory Roles of Low-Cell-Density Quorum-Sensing Regulator AphA in the Pathogen Vibrio alginolyticus

A Cytotoxic Type III Secretion Effector of Vibrio parahaemolyticus Targets Vacuolar H+-ATPase Subunit c and Ruptures Host Cell Lysosomes

ExsE Is a Negative Regulator for T3SS Gene Expression in Vibrio alginolyticus

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