scholarly journals The type III secretion system of Vibrio alginolyticus induces rapid apoptosis, cell rounding and osmotic lysis of fish cells

Microbiology ◽  
2010 ◽  
Vol 156 (9) ◽  
pp. 2864-2872 ◽  
Author(s):  
Zhe Zhao ◽  
Chang Chen ◽  
Chao-Qun Hu ◽  
Chun-Hua Ren ◽  
Jing-Jing Zhao ◽  
...  
Keyword(s):  
Cell Death ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Infected Fish ◽  
Secretion System ◽  
Vibrio Alginolyticus ◽  
Marine Animals ◽  
Cell Rounding ◽  
Type Iii ◽  
Fish Cells

Vibrio alginolyticus is a Gram-negative bacterium and has been recognized as an opportunistic pathogen in humans as well as marine animals. However, the virulence mechanisms for this species of Vibrio have not been elucidated. This study characterized multiple mechanisms that induce cell death in fish cells upon infection with a V. alginolyticus strain, ZJO. The bacterium required its type III secretion system (T3SS) to cause rapid death of infected fish cells. Dying cells exhibited some features of apoptotic cells, such as membrane blebbing, nuclear condensation and DNA fragmentation. Further studies showed that caspase-3 was activated by the T3SS of the ZJO strain, confirming that infection with V. alginolyticus rapidly induces T3SS-dependent apoptosis in fish cells. Infection with the ZJO strain also led to membrane pore formation and release of cellular contents from infected fish cells, as evidenced by lactate dehydrogenase release and the uptake of a membrane-impermeable dye. Importantly, inhibition of apoptosis did not prevent ZJO-infected cells from releasing cellular contents and did not block cell rounding. Taken together, these data demonstrate that infection with V. alginolyticus may promote at least three different T3SS-dependent events, which lead to the death of fish cells. This study provides an important insight into the mechanism used by Vibrio species to cause host-cell death.

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

2010 ◽  
Vol 193 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Zhe Zhao ◽  
Lvping Zhang ◽  
Chunhua Ren ◽  
Jingjing Zhao ◽  
Chang Chen ◽  
...  
Keyword(s):  
Cell Lines ◽  
Mammalian Cell ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Vibrio Alginolyticus ◽  
Type Iii ◽  
Mammalian Cell Lines

scholarly journals SseK1 and SseK3 Type III Secretion System Effectors Inhibit NF-κB Signaling and Necroptotic Cell Death in Salmonella-Infected Macrophages

2017 ◽  
Vol 85 (3) ◽  
Author(s):  
Regina A. Günster ◽  
Sophie A. Matthews ◽  
David W. Holden ◽  
Teresa L. M. Thurston
Keyword(s):  
Cell Death ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Host Cells ◽  
Macrophage Infection ◽  
Content Type ◽  
Type Iii ◽  
Tnf Α ◽  
Arginine Residues

ABSTRACT Within host cells such as macrophages, Salmonella enterica translocates virulence (effector) proteins across its vacuolar membrane via the SPI-2 type III secretion system. Previously, it was shown that when expressed ectopically, the effectors SseK1 and SseK3 inhibit tumor necrosis factor alpha (TNF-α)-induced NF-κB activation. In this study, we show that ectopically expressed SseK1, SseK2, and SseK3 suppress TNF-α-induced, but not Toll-like receptor 4- or interleukin-induced, NF-κB activation. Inhibition required a DXD motif in SseK1 and SseK3, which is essential for the transfer of N-acetylglucosamine to arginine residues (arginine-GlcNAcylation). During macrophage infection, SseK1 and SseK3 inhibited NF-κB activity in an additive manner. SseK3-mediated inhibition of NF-κB activation did not require the only known host-binding partner of this effector, the E3-ubiquitin ligase TRIM32. SseK proteins also inhibited TNF-α-induced cell death during macrophage infection. Despite SseK1 and SseK3 inhibiting TNF-α-induced apoptosis upon ectopic expression in HeLa cells, the percentage of infected macrophages undergoing apoptosis was SseK independent. Instead, SseK proteins inhibited necroptotic cell death during macrophage infection. SseK1 and SseK3 caused GlcNAcylation of different proteins in infected macrophages, suggesting that these effectors have distinct substrate specificities. Indeed, SseK1 caused the GlcNAcylation of the death domain-containing proteins FADD and TRADD, whereas SseK3 expression resulted in weak GlcNAcylation of TRADD but not FADD. Additional, as-yet-unidentified substrates are likely to explain the additive phenotype of a Salmonella strain lacking both SseK1 and SseK3.

scholarly journals A Survey of the Pseudomonas syringae pv. tomato DC3000 Type III Secretion System Effector Repertoire Reveals Several Effectors That Are Deleterious When Expressed in Saccharomyces cerevisiae

2008 ◽  
Vol 21 (4) ◽  
pp. 490-502 ◽  
Author(s):  
Kathy R. Munkvold ◽  
Michael E. Martin ◽  
Philip A. Bronstein ◽  
Alan Collmer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Death ◽  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Dependent Manner ◽  
Tomato Dc3000 ◽  
Type Iii ◽  
Pathogen Effector

The injection of nearly 30 effector proteins by the type III secretion system underlies the ability of Pseudomonas syringae pv. tomato DC3000 to cause disease in tomato and other host plants. The search for effector functions is complicated by redundancy within the repertoire and by plant resistance (R)-gene sentinels, which may convert effector virulence activities into a monolithic defense response. On the premise that some effectors target universal eukaryotic processes and that yeast (Saccharomyces cerevisiae) lacks R genes, the DC3000 effector repertoire was expressed in yeast. Of 27 effectors tested, HopAD1, HopAO1, HopD1, HopN1, and HopU1 were found to inhibit growth when expressed from a galactose-inducible GAL1 promoter, and HopAA1-1 and HopAM1 were found to cause cell death. Catalytic site mutations affecting the tyrosine phosphatase activity of HopAO1 and the cysteine protease activity of HopN1 prevented these effectors from inhibiting yeast growth. Expression of HopAA1-1, HopAM1, HopAD1, and HopAO1 impaired respiration in yeast, as indicated by tests with ethanol glycerol selective media. HopAA1-1 colocalized with porin to yeast mitochondria and was shown to cause cell death in yeast and plants in a domain-dependent manner. These results support the use of yeast for the study of plant-pathogen effector repertoires.

scholarly journals Type III Secretion System-Dependent Translocation of Ectopically Expressed Yop Effectors into Macrophages by Intracellular Yersinia pseudotuberculosis

2011 ◽  
Vol 79 (11) ◽  
pp. 4322-4331 ◽  
Author(s):  
Yue Zhang ◽  
Galina Romanov ◽  
James B. Bliska
Keyword(s):  
Cell Death ◽  
Type Iii Secretion ◽  
Yersinia Pseudotuberculosis ◽  
Bacterial Pathogen ◽  
Type Iii Secretion System ◽  
Inducible Promoter ◽  
Secretion System ◽  
Host Cells ◽  
Content Type ◽  
Type Iii

ABSTRACTYersinia pseudotuberculosisis a Gram-negative bacterial pathogen. Virulence inY. pseudotuberculosisrequires the plasmid-encoded Ysc type III secretion system (T3SS), which functions to translocate a set of effectors called Yops into infected host cells. The effectors function to antagonize phagocytosis (e.g., YopH) or to induce apoptosis (YopJ) in macrophages infected withY. pseudotuberculosis. Additionally, when antiphagocytosis is incomplete andY. pseudotuberculosisis internalized by macrophages, the bacterium can survive in phagosomes. Previous studies have shown that delivery of effectors into host cells occurs efficiently whenYersiniais extracellular. However, it is not clear whether the T3SS can be utilized by intracellularY. pseudotuberculosisto translocate Yops. This possibility was investigated here usingY. pseudotuberculosisstrains that express YopJ or YopH under the control of an inducible promoter. Bone marrow-derived murine macrophages were infected with these strains under conditions that prevented the survival of extracellular bacteria. Effector translocation was detected by measuring apoptosis or the activities of Yop-β-lactamase fusion proteins. Results showed that macrophages underwent apoptosis when YopJ expression was induced prior to phagocytosis, confirming that delivery of this effector prior to or during uptake is sufficient to cause cell death. However, macrophages also underwent apoptosis when YopJ was ectopically expressed after phagocytosis; furthermore, expression of the translocator YopB from intracellular bacteria also resulted in increased cell death. Analysis by microscopy showed that translocation of ectopically expressed YopH- or YopJ-β-lactamase fusions could be correlated with the presence of viableY. pseudotuberculosisin macrophages. Collectively, our results suggest that the Ysc T3SS ofY. pseudotuberculosiscan function within macrophage phagosomes to translocate Yops into the host cytosol.

scholarly journals Caspase-1 Activation in Macrophages Infected with Yersinia pestis KIM Requires the Type III Secretion System Effector YopJ

2008 ◽  
Vol 76 (9) ◽  
pp. 3911-3923 ◽  
Author(s):  
Sarit Lilo ◽  
Ying Zheng ◽  
James B. Bliska
Keyword(s):  
Cell Death ◽  
Yersinia Pestis ◽  
Type Iii Secretion ◽  
Yersinia Pseudotuberculosis ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Host Cells ◽  
Enzyme Linked Immunosorbent Assay ◽  
Type Iii ◽  
Caspase 1

ABSTRACT Pathogenic Yersinia species utilize a type III secretion system (T3SS) to translocate effectors called Yersinia outer proteins (Yops) into infected host cells. Previous studies demonstrated a role for effector Yops in the inhibition of caspase-1-mediated cell death and secretion of interleukin-1β (IL-1β) in naïve macrophages infected with Yersinia enterocolitica. Naïve murine macrophages were infected with a panel of different Yersinia pestis and Yersinia pseudotuberculosis strains to determine whether Yops of these species inhibit caspase-1 activation. Cell death was measured by release of lactate dehydrogenase (LDH), and enzyme-linked immunosorbent assay for secreted IL-1β was used to measure caspase-1 activation. Surprisingly, isolates derived from the Y. pestis KIM strain (e.g., KIM5) displayed an unusual ability to activate caspase-1 and kill infected macrophages compared to other Y. pestis and Y. pseudotuberculosis strains tested. Secretion of IL-1β following KIM5 infection was reduced in caspase-1-deficient macrophages compared to wild-type macrophages. However, release of LDH was not reduced in caspase-1-deficient macrophages, indicating that cell death occurred independently of caspase-1. Analysis of KIM-derived strains defective for production of functional effector or translocator Yops indicated that translocation of catalytically active YopJ into macrophages was required for caspase-1 activation and cell death. Release of LDH and secretion of IL-1β were not reduced when actin polymerization was inhibited in KIM5-infected macrophages, indicating that extracellular bacteria translocating YopJ could trigger cell death and caspase-1 activation. This study uncovered a novel role for YopJ in the activation of caspase-1 in macrophages.

Type III secretion system 1 of Vibrio parahaemolyticus induces oncosis in both epithelial and monocytic cell lines

Microbiology ◽  
2009 ◽  
Vol 155 (3) ◽  
pp. 837-851 ◽  
Author(s):  
Xiaohui Zhou ◽  
Michael E. Konkel ◽  
Douglas R. Call
Keyword(s):  
Cell Death ◽  
Cell Lines ◽  
Type Iii Secretion ◽  
Vibrio Parahaemolyticus ◽  
Active Form ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Monocytic Cell ◽  
Type Iii ◽  
System 1

The Vibrio parahaemolyticus type III secretion system 1 (T3SS1) induces cytotoxicity in mammalian epithelial cells. We characterized the cell death phenotype in both epithelial (HeLa) and monocytic (U937) cell lines following infection with V. parahaemolyticus. Using a combination of the wild-type strain and gene knockouts, we confirmed that V. parahaemolyticus strain NY-4 was able to induce cell death in both cell lines via a T3SS1-dependent mechanism. Bacterial contact, but not internalization, was required for T3SS1-induced cytotoxicity. The mechanism of cell death involves formation of a pore structure on the surface of infected HeLa and U937 cells, as demonstrated by cellular swelling, uptake of cell membrane-impermeable dye and protection of cytotoxicity by osmoprotectant (PEG3350). Western blot analysis showed that poly ADP ribose polymerase (PARP) was not cleaved and remained in its full-length active form. This result was evident for seven different V. parahaemolyticus strains. V. parahaemolyticus-induced cytotoxicity was not inhibited by addition of the pan-caspase inhibitor carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]-fluoromethylketone (Z-VAD-FMK) or the caspase-1 inhibitor N-acetyl-tyrosyl-valyl-alanyl-aspartyl-aldehyde (Ac-YVAD-CHO); thus, caspases were not involved in T3SS1-induced cytotoxicity. DNA fragmentation was not evident following infection and autophagic vacuoles were not observed after monodansylcadaverine staining. We conclude that T3SS1 of V. parahaemolyticus strain NY-4 induces a host cell death primarily via oncosis rather than apoptosis, pyroptosis or autophagy.

scholarly journals Neutrophils Are Resistant to Yersinia YopJ/P-Induced Apoptosis and Are Protected from ROS-Mediated Cell Death by the Type III Secretion System

PLoS ONE ◽  
2010 ◽  
Vol 5 (2) ◽  
pp. e9279 ◽  
Author(s):  
Justin L. Spinner ◽  
Keun Seok Seo ◽  
Jason L. O'Loughlin ◽  
Jennifer A. Cundiff ◽  
Scott A. Minnich ◽  
...  
Keyword(s):  
Cell Death ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Type Iii ◽  
Induced Apoptosis
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