Xenorhabdus nematophila (Enterobacteriacea) Secretes a Cation-selective Calcium-independent Porin Which Causes Vacuolation of the Rough Endoplasmic Reticulum and Cell Lysis

Ribeiro, Carlos; Vignes, Michel; Brehélin, Michel

doi:10.1074/jbc.m210353200

Cited by 46 publications

(36 citation statements)

References 36 publications

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“…ShlA-induced vacuoles, however, do not appear to be derived from late endosomes. Alpha toxin of Xenorhabdus triggers endoplasmic reticulum vacuolation by increasing monovalent cation permeability of the membrane, resulting in cell death by colloid-osmotic lysis (Ribeiro et al, 2003). An early in vivo study showed that V. parahaemolyticus-infected mice displayed congestion, oedema and vacuolation in mucosal and submucosal tissues (Hoashi et al, 1990).…”

Section: Discussionmentioning

confidence: 99%

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

2009

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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-valylalanyl-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. INTRODUCTIONVibrio parahaemolyticus is a Gram-negative food-borne pathogen that is commonly associated with consumption of raw or undercooked seafood (Joseph et al., 1982). Symptoms of infection include diarrhoea, nausea, vomiting, headache, fever and chills. In addition to typical gastrointestinal infections, approximately 5 % of V. parahaemolyticus infections advance to septicaemia (Hlady & Klontz, 1996) and these infections may be fatal, especially in immunocompromised patients or those with a preexisting medical condition such as liver disease or diabetes (Yeung & Boor, 2004).Thermostable direct haemolysin (TDH) is considered the primary virulence factor in V. parahaemolyticus. In addition to its ability to form pores in red blood cells, TDH causes increased short circuit current, increased Cl 2 secretion in human colonic epithelial cells, and enhanced Ca 2+ entry from the extracellular medium (Takahashi et al., 2001). An early study of a tdh deletion mutant demonstrated significantly reduced ability to cause fluid accumulation in ileal loops of a rabbit model (Nishibuchi et al., 1992). In contrast, Park et al. (2004) showed that a tdh deletion mutant has the ability to cause fluid accumulation in the ligated intestine of rabbits. Furthermore, both TDH-positive and -negative strains of V. parahaemolyticus can disrupt the epithelial tight junction, a precursor to dissemination of bacteria into the circulation (Lynch et a...

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Section: Discussionmentioning

confidence: 99%

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

2009

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“…Various studies have shown that the nematobacterial complex attenuates insect cellular reactions in the hemolymph. The inhibition of nodule formation was studied in vivo (8,16,17), and cytotoxic factors active against hemocytes have been identified in vitro (4,21,22). The mode of action of a cytolytic factor on immunocytes (cells of the insect hemolymph) was recently characterized in detail (22).…”

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confidence: 99%

Stages of Infection during the Tripartite Interaction between Xenorhabdus nematophila , Its Nematode Vector, and Insect Hosts

Sicard

Brugirard-Ricaud

Pagès

et al. 2004

Appl Environ Microbiol

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114

113

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Bacteria of the genus Xenorhabdus are mutually associated with entomopathogenic nematodes of the genus Steinernema and are pathogenic to a broad spectrum of insects. The nematodes act as vectors, transmitting the bacteria to insect larvae, which die within a few days of infection. We characterized the early stages of bacterial infection in the insects by constructing a constitutive green fluorescent protein (GFP)-labeled Xenorhabdus nematophila strain. We injected the GFP-labeled bacteria into insects and monitored infection. We found that the bacteria had an extracellular life cycle in the hemolymph and rapidly colonized the anterior midgut region in Spodoptera littoralis larvae. Electron microscopy showed that the bacteria occupied the extracellular matrix of connective tissues within the muscle layers of the Spodoptera midgut. We confirmed the existence of such a specific infection site in the natural route of infection by infesting Spodoptera littoralis larvae with nematodes harboring GFP-labeled Xenorhabdus. When the infective juvenile (IJ) nematodes reached the insect gut, the bacterial cells were rapidly released from the intestinal vesicle into the nematode intestine. Xenorhabdus began to escape from the anus of the nematodes when IJs were wedged in the insect intestinal wall toward the insect hemolymph. Following their release into the insect hemocoel, GFP-labeled bacteria were found only in the anterior midgut region and hemolymph of Spodoptera larvae. Comparative infection assays conducted with another insect, Locusta migratoria, also showed early bacterial colonization of connective tissues. This work shows that the extracellular matrix acts as a particular colonization site for X. nematophila within insects.

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“…The size variation could be due to differences in the lipid composition of the membranes in liposomes and the target cells, allowing variable numbers of subunits to assemble in the pore. Toxin proteins producing pores of different size in different cell types have been reported earlier (30).…”

Section: Fig 2 Effect Of Mrxa On Larval Hemocytes and Their Protectmentioning

confidence: 99%

“…Pore-forming toxic proteins facilitate entry of the pathogen and/or damage the host cell for their own ends. In addition to the orally toxic proteins (7), X. nematophila is reported to produce a 10-kDa cytotoxic, cation-selective channel-forming protein in the culture medium (30). To understand the mode of action of cytotoxic fimbrial subunit MrxA of X. nematophila, we have investigated the pore-forming activity of the protein.…”

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confidence: 99%

The Cytotoxic Fimbrial Structural Subunit of Xenorhabdus nematophila Is a Pore-Forming Toxin

et al. 2006

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We have purified a fimbrial shaft protein (MrxA) of Xenorhabdus nematophila. The soluble monomeric protein lysed larval hemocytes of Helicoverpa armigera. Osmotic protection of the cells with polyethylene glycol suggested that the 17-kDa MrxA subunit makes pores in the target cell membrane. The internal diameter of the pores was estimated to be >2.9 nm. Electron microscopy confirmed the formation of pores by the fimbrial subunit. MrxA protein oligomerized in the presence of liposomes. Electrophysiological studies demonstrated that MrxA formed large, voltage-gated passive-diffusion channels in lipid bilayers.

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Xenorhabdus nematophila (Enterobacteriacea) Secretes a Cation-selective Calcium-independent Porin Which Causes Vacuolation of the Rough Endoplasmic Reticulum and Cell Lysis

Cited by 46 publications

References 36 publications

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

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

Stages of Infection during the Tripartite Interaction between Xenorhabdus nematophila , Its Nematode Vector, and Insect Hosts

The Cytotoxic Fimbrial Structural Subunit of Xenorhabdus nematophila Is a Pore-Forming Toxin

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