Vibrio cholerae Cytolysin Causes an Inflammatory Response in Human Intestinal Epithelial Cells That Is Modulated by the PrtV Protease

Ou, Gangwei; Rompikuntal, Pramod Kumar; Bitar, Aziz; Lindmark, Barbro; Vaitkevicius, Karolis; Wai, Sun Nyunt; Hammarström, Marie‐Louise

doi:10.1371/journal.pone.0007806

Cited by 29 publications

(31 citation statements)

References 33 publications

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“…Upregulation of IL-1␣, IL-1␤, TNF-␣, IL-8, and MCP-1 has been found in V. cholerae-infected fully differentiated T84 cells, whereas a striking dissimilarity in cytokine expression was observed in infected fully differentiated Caco-2 cells (759). The increased paracellular permeability and production of IL-8 and TNF-␣ in V. cholerae-infected fully differentiated T84 cells have been found to be triggered by the V. cholerae protease PrtV and V. cholerae cytolysin (VCC) (760).…”

Section: Host Cellular Defense Responsesmentioning

confidence: 99%

Pathogenesis of Human Enterovirulent Bacteria: Lessons from Cultured, Fully Differentiated Human Colon Cancer Cell Lines

Moal

Servin

2013

Microbiol Mol Biol Rev

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SUMMARY Hosts are protected from attack by potentially harmful enteric microorganisms, viruses, and parasites by the polarized fully differentiated epithelial cells that make up the epithelium, providing a physical and functional barrier. Enterovirulent bacteria interact with the epithelial polarized cells lining the intestinal barrier, and some invade the cells. A better understanding of the cross talk between enterovirulent bacteria and the polarized intestinal cells has resulted in the identification of essential enterovirulent bacterial structures and virulence gene products playing pivotal roles in pathogenesis. Cultured animal cell lines and cultured human nonintestinal, undifferentiated epithelial cells have been extensively used for understanding the mechanisms by which some human enterovirulent bacteria induce intestinal disorders. Human colon carcinoma cell lines which are able to express in culture the functional and structural characteristics of mature enterocytes and goblet cells have been established, mimicking structurally and functionally an intestinal epithelial barrier. Moreover, Caco-2-derived M-like cells have been established, mimicking the bacterial capture property of M cells of Peyer's patches. This review intends to analyze the cellular and molecular mechanisms of pathogenesis of human enterovirulent bacteria observed in infected cultured human colon carcinoma enterocyte-like HT-29 subpopulations, enterocyte-like Caco-2 and clone cells, the colonic T84 cell line, HT-29 mucus-secreting cell subpopulations, and Caco-2-derived M-like cells, including cell association, cell entry, intracellular lifestyle, structural lesions at the brush border, functional lesions in enterocytes and goblet cells, functional and structural lesions at the junctional domain, and host cellular defense responses.

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Section: Host Cellular Defense Responsesmentioning

confidence: 99%

Pathogenesis of Human Enterovirulent Bacteria: Lessons from Cultured, Fully Differentiated Human Colon Cancer Cell Lines

Moal

Servin

2013

Microbiol Mol Biol Rev

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“…Having found that V. cholerae induces neutrophil recruitment and a subset of proinflammatory factors in infant C57BL/6 mice at 24 to 30 h postinfection, we investigated bacterial factors that could contribute to the induction of inflammation. The toxins HlyA and RtxA are encoded within the genomes of all V. cholerae strains, regardless of whether they have acquired CTX, and have been implicated in inflammation with epithelial cells in vitro and in adult mouse models of V. cholerae infection (19,21,22,28). Mutants deleted for genes encoding RtxA or HlyA were investigated for PMN recruitment in infant mice.…”

Section: Inflammatory Markers Observed By Qrt-pcr In the Infantmentioning

confidence: 99%

“…In the infant rabbit model, flagellin-independent inflammation was still observed, suggesting that V. cholerae encodes other minor proinflammatory factors (16). In tissue culture models, purified V. cholerae O1 lipopolysaccharide (LPS) induces the proinflammatory transcription factor NF-B (18), and hemolysin A (HlyA) contributes to inflammation induced by non-O1/ non-O139 V. cholerae supernatants (19). Repeats toxin, encoded by rtxA and elaborated by the El Tor V. cholerae O1 biotype, but not the extinct classical biotype (20), was implicated in El Torinduced inflammation in an adult mouse pulmonary infection model (21), and both HlyA and RtxA are required for virulence in a mouse model of prolonged colonization (22).…”

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confidence: 99%

Vibrio cholerae-Induced Inflammation in the Neonatal Mouse Cholera Model

2014

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Vibrio cholerae is the causative agent of the acute diarrheal disease of cholera. Innate immune responses to V. cholerae are not a major cause of cholera pathology, which is characterized by severe, watery diarrhea induced by the action of cholera toxin. Innate responses may, however, contribute to resolution of infection and must be required to initiate adaptive responses after natural infection and oral vaccination. Here we investigated whether a well-established infant mouse model of cholera can be used to observe an innate immune response. We also used a vaccination model in which immunized dams protect their pups from infection through breast milk antibodies to investigate innate immune responses after V. cholerae infection for pups suckled by an immune dam. At the peak of infection, we observed neutrophil recruitment accompanied by induction of KC, macrophage inflammatory protein 2 (MIP-2), NOS-2, interleukin-6 (IL-6), and IL-17a. Pups suckled by an immunized dam did not mount this response. Accessory toxins RtxA and HlyA played no discernible role in neutrophil recruitment in a wild-type background. The innate response to V. cholerae deleted for cholera toxin-encoding phage (CTX) and part of rtxA was significantly reduced, suggesting a role for CTX-carried genes or for RtxA in the absence of cholera toxin (CTX). Two extracellular V. cholerae DNases were not required for neutrophil recruitment, but DNase-deficient V. cholerae caused more clouds of DNA in the intestinal lumen, which appeared to be neutrophil extracellular traps (NETs), suggesting that V. cholerae DNases combat NETs. Thus, the infant mouse model has hitherto unrecognized utility for interrogating innate responses to V. cholerae infection. Vibrio cholerae is the causative agent of cholera, which remains endemic in many regions of Africa and Asia (1). Sporadic outbreaks can devastate immunologically naïve populations, such as occurred in Haiti in 2010 (2). The O1 serogroup and, to a lesser degree, O139 are the major causes of cholera, and El Tor is currently the circulating O1 biotype (1). Cholera toxin (CTX), encoded by a lysogenic phage (3), is the major cause of the severe secretory diarrhea that is typical of cholera. Without rehydration therapy, cholera results in 25 to 50% mortality, but if treated, cholera will resolve in most patients (4). Unlike diseases such as shigellosis and Salmonella-induced gastroenteritis (5, 6), the pathology of cholera is not immune driven. However, innate immune responses have been observed in cholera patients during the acute phase of infection (7) and likely play a direct and/or indirect role in the resolution of disease. The majority of individuals who survive a bout of cholera will become immune to subsequent infection for at least 3 years (8-10), and some aspects of the observed innate immune response must be required to initiate this protective immunity.Many live attenuated vaccine candidate strains of V. cholerae have been developed in which ctxA, the gene encoding the catalytic subunit of cholera tox...

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“…Therefore, it may be suggested that the presence of metalloprotease PrtV in CHA6.8 OMVs may be responsible for increased OMV-mediated cytotoxicity. However, earlier studies have shown that PrtV modulates IL-8 secretion from T84 cells (46). Interestingly, when cells were treated with CHA6.8 ⌬prtV, a shift from an apoptotic population to a necrotic population was observed.…”

Section: Discussionmentioning

confidence: 78%

Cytotoxic and Inflammatory Responses Induced by Outer Membrane Vesicle-Associated Biologically Active Proteases from Vibrio cholerae

et al. 2016

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e Proteases in Vibrio cholerae have been shown to play a role in its pathogenesis. V. cholerae secretes Zn-dependent hemagglutinin protease (HAP) and calcium-dependent trypsin-like serine protease (VesC) by using the type II secretion system (TIISS). Our present studies demonstrated that these proteases are also secreted in association with outer membrane vesicles (OMVs) and transported to human intestinal epithelial cells in an active form. OMV-associated HAP induces dose-dependent apoptosis in Int407 cells and an enterotoxic response in the mouse ileal loop (MIL) assay, whereas OMV-associated VesC showed a hemorrhagic fluid response in the MIL assay, necrosis in Int407 cells, and an increased interleukin-8 (IL-8) response in T84 cells, which were significantly reduced in OMVs from VesC mutant strain. Our results also showed that serine protease VesC plays a role in intestinal colonization of V. cholerae strains in adult mice. In conclusion, our study shows that V. cholerae OMVs secrete biologically active proteases which may play a role in cytotoxic and inflammatory responses. Vibrio cholerae is the causative agent of the life-threatening disease cholera. Cholera epidemics in Haiti in 2010 provide evidence that it still remains an ongoing public health threat (1). Strains of the El Tor biotype O1 serogroup are responsible for seventh pandemic and recent cholera outbreaks (2). Cholera toxin (CT) and toxin-coregulated pilus (TCP) have been identified as the major virulence factors for V. cholerae pathogenesis. CT is responsible for profuse watery diarrhea, whereas TCP is essential for sustaining colonization of human small intestine. V. cholerae also secretes several proteases which may also play a role in its pathogenesis (3).The major protease secreted by V. cholerae strains is the 35-kDa hemagglutinin protease (HAP) (4). HAP has been reported to accelerate the bacterial detachment from cultured cells by digestion of V. cholerae adhesins (5). HAP modulates the enterotoxigenicity of cholera toxin by nicking the A subunit of CT (6). HAP also plays a role in processing hemolysin to its mature form by removal of a 15-kDa N-terminal peptide (7). As shown in the above-mentioned studies, HAP plays an indirect role in V. cholerae pathogenesis. The possibility of its direct role in pathogenesis has been shown by Ghosh et al. (8). They reported that purified HAP from a V. cholerae non-O1, non-O139 strain showed a hemorrhagic response in rabbit ileal loops (RILs) and an increase in intestinal short-circuit current in Ussing's chamber (8). Besides HAP, the other major well-characterized metalloprotease is a 97-kDa Vibrio cholerae protease, PrtV which has been shown to play a role in virulence in the Caenorhabditis elegans infection model (9). In an earlier study, we also reported the presence of a novel serine protease encoded by VC1649 (VesC) in a hapA prtV mutant Vibrio cholerae O1 strain and showed its role in the hemorrhagic response in the rabbit ileal loop model (10).Gram-negative bacteria, including V. cholerae, us...

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Vibrio cholerae Cytolysin Causes an Inflammatory Response in Human Intestinal Epithelial Cells That Is Modulated by the PrtV Protease

Cited by 29 publications

References 33 publications

Pathogenesis of Human Enterovirulent Bacteria: Lessons from Cultured, Fully Differentiated Human Colon Cancer Cell Lines

Pathogenesis of Human Enterovirulent Bacteria: Lessons from Cultured, Fully Differentiated Human Colon Cancer Cell Lines

Vibrio cholerae-Induced Inflammation in the Neonatal Mouse Cholera Model

Cytotoxic and Inflammatory Responses Induced by Outer Membrane Vesicle-Associated Biologically Active Proteases from Vibrio cholerae

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