Cadaverine Prevents the Escape of<i>Shigella flexneri</i>from the Phagolysosome: A Connection between Bacterial Dissemination and Neutrophil Transepithelial Signaling

Fernandez, Isabel M.; Silva, Milton; Schuch, Raymond; Walker, W. Allan; Siber, Andrew M.; Maurelli, Anthony T.; McCormick, Beth A.

doi:10.1086/323035

Cited by 67 publications

(48 citation statements)

References 43 publications

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“…The relevance of these findings is supported by previous studies in which the modulation of amino acid metabolism has been linked to the ability of bacterial pathogens to survive and, in some cases, to adhere to the gastrointestinal tract and has been proposed as a property which plays an important role in the colonization of host intestine (3,18,20,31) or the urinary tract (55).…”

Section: Discussionsupporting

confidence: 66%

“…The cadA gene encodes the lysine decarboxylase enzyme, responsible for metabolizing lysine, and these investigators found that loss to lysine decarboxylase (LDC) activity was due to a large chromosomal deletion comprising the cadA region (16). Further studies indicated that introduction of cadA in S. flexneri affects the activity of two enterotoxins and the presence of the byproduct cadaverine, generated from the decarboxylation of lysine, caused attenuation in S. flexneri virulence (18,33).…”

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confidence: 99%

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Pathoadaptive Mutation That Mediates Adherence of Shiga Toxin-Producing Escherichia coli O111

Torres

Vázquez-Juárez

Tutt³

et al. 2005

Infect Immun

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The adherence of pathogenic Escherichia coli strains to intestinal epithelium is essential for initiation of infection. The cad operon encodes the lysine decarboxylase (LDC) system responsible for metabolizing lysine, and this operon has been proposed as an antivirulence mechanism in enteroinvasive E. coli and Shigella flexneri and as a factor mediating E. coli O157:H7 adherence. We sought to determine whether the LDC activity was present in a phylogenetically characterized collection of diarrheagenic E. coli (DEC) strains and to establish whether its expression was associated with their adherence to tissue culture cells. LDC activity was found in most of the pathogenic E. coli strains tested and was absent from Shiga toxin-producing E. coli (STEC) O111 strains (DEC pathotype 8). Analysis of the cad region in these O111 strains indicates that the operon has been rearranged and some of the genes are either missing or disrupted. A similar rearrangement was found in an E. coli O111:H8 strain recently isolated from an outbreak in Texas. Complementation of the LDC-negative strains with the cad operon in trans restored the LDC activity and resulted in a reduction in adherence to tissue culture cells. Initial analysis of the protein profiles on the surface of the O111 strains indicates that the LDC activity has an effect on the expression of the adhesin intimin. Cadaverine had a slight effect on LDC-negative strain adhesion but none on intimin expression. Our data suggest that this pathoadaptive mutation is an important mechanism to control functions potentially implicated in the pathogenesis of these organisms.

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Section: Discussionsupporting

confidence: 66%

mentioning

confidence: 99%

Pathoadaptive Mutation That Mediates Adherence of Shiga Toxin-Producing Escherichia coli O111

Torres

Vázquez-Juárez

Tutt³

et al. 2005

Infect Immun

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“…Despite the beneficial role that the CadBAC lysine-dependent acid resistance system might have in the survival of enteric organisms in the intestine, cumulative evidence indicates that the absence of these genes, due to deletions or insertional mutagenesis, in some members of the family Enterobacteriaceae results in an enhancement of their virulence phenotype (31). For example, it is well documented that attenuation of virulence phenotypes in Shigella flexneri 2a has been linked to expression of LDC and, specifically, to the production of cadaverine (7,18,19). These studies demonstrated for the first time that the cadA gene acts as an antivirulence gene for Shigella.…”

Section: Discussionmentioning

confidence: 99%

CadA Negatively Regulates Escherichia coli O157:H7 Adherence and Intestinal Colonization

Vázquez-Juárez

Kuriakose²,

Rasko

et al. 2008

Infect Immun

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Adherence of pathogenicOne of these factors is CadA, a lysine decarboxylase, and this protein has been proposed to negatively regulate virulence in several enteric pathogens. In the case of EHEC strains, CadA modulates expression of the intimin, an outer membrane adhesin involved in pathogenesis. Here, we inactivated cadA in O157:H7 strain 86-24 to investigate the role of this gene in EHEC adhesion to tissue-cultured monolayers, global gene expression patterns, and colonization of the infant rabbit intestine. The cadA mutant did not possess lysine decarboxylation activity and was hyperadherent to tissue-cultured cells. Adherence of the cadA mutant was nearly twofold greater than that of the wild type, and the adherence phenotype was independent of pH, lysine, or cadaverine in the media. Additionally, complementation of the cadA defect reduced adherence back to wild-type levels, and it was found that the mutation affected the expression of the intimin protein. Disruption of the eae gene (intimin-encoding gene) in the cadA mutant significantly reduced its adherence to tissue-cultured cells. However, adherence of the cadA eae double mutant was greater than that of an 86-24 eae mutant, suggesting that the enhanced adherence of the cadA mutant is not entirely attributable to enhanced expression of intimin in this background. Gene array analysis revealed that the cadA mutation significantly altered EHEC gene expression patterns; expression of 1,332 genes was downregulated and that of 132 genes was upregulated in the mutant compared to the wild-type strain. Interestingly, the gene expression variation shows an EHEC-biased gene alteration including intergenic regions. Two putative adhesins, flagella and F9 fimbria, were upregulated in the cadA mutant, suggestive of their association with adherence in the absence of the Cad regulatory mechanism. In the infant rabbit model, the cadA mutant outcompeted the wild-type strain in the ileum but not in the cecum or mid-colon, raising the possibility that CadA negatively regulates EHEC pathogenicity in a tissue-specific fashion.

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“…The human epithelial colon cancer-derived cell line T84 (passages 46 to 66) was maintained in DMEM/F-12 supplemented with 15 mM HEPES (pH 7.5) and 10% FBS. To obtain polarized monolayers, T84 cells were grown on 0.33-or 4.7-cm 2 collagen-coated permeable polycarbonate filters (Costar) that had pore sizes of 5.0 and 3.0 m, respectively, and they were utilized after they reached a confluent and differentiated state, as previously described (5,21,31). All tissue culture media were acquired from Invitrogen, and all cell lines were maintained in the presence of 5% CO 2 at 37°C.…”

Section: Methodsmentioning

confidence: 99%

“…The primary function of the T3SS is to secrete proteins, called effectors, into the host to modify cell function and overcome cell defenses (15,34). In S. flexneri pathogenesis, the T3SS is required for invasion, vacuolar escape, cell-to-cell spread, and PMN transepithelial migration (5,17,31,48). The transcription and expression of the S. flexneri T3SS are induced by the VirF/VirB system when the temperature is shifted from 30°C to 37°C (54).…”

mentioning

confidence: 99%

OspF and OspC1 Are Shigella flexneri Type III Secretion System Effectors That Are Required for Postinvasion Aspects of Virulence

et al. 2006

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Shigella flexneri is the causative agent of dysentery, and its pathogenesis is mediated by a type III secretion system (T3SS). S. flexneri secretes effector proteins into the eukaryotic cell via the T3SS, and these proteins usurp host cellular functions to the benefit of the bacteria. OspF and OspC1 are known to be secreted by S. flexneri, but their functions are unknown. We transformed S. flexneri with a plasmid that expresses a twohemagglutinin tag (2HA) in frame with OspF or OspC1 and verified that these proteins are secreted in a T3SS-dependent manner. Immunofluorescence of HeLa cells infected with S. flexneri expressing OspF-2HA or OspC1-2HA revealed that both proteins localize in the nucleus and cytoplasm of host cells. To elucidate the function of these T3SS effectors, we constructed ⌬ospF and ⌬ospC1 deletion mutants by allelic exchange. We found that ⌬ospF and ⌬ospC1 mutants invade host cells and form plaques in confluent monolayers similar to wild-type S. flexneri. However, in the polymorphonuclear (PMN) cell migration assay, a decrease in neutrophil migration was observed for both mutants in comparison to the migration of wild-type bacteria. Moreover, infection of polarized T84 intestinal cells infected with ⌬ospF and ⌬ospC1 mutants resulted in decreased phosphorylation of extracellular signal-regulated kinase 1/2 in comparison to that of T84 cells infected with wild-type S. flexneri. To date, these are the first examples of T3SS effectors implicated in mitogen-activated protein kinase kinase/extracellular signal-regulated kinase pathway activation. Ultimately, OspF and OspC1 are essential for PMN transepithelial migration, a phenotype associated with increased inflammation and bacterial access to the submucosa, which are fundamental aspects of S. flexneri pathogenesis.Shigella species are responsible for dysentery (shigellosis) in humans, which starts as an acute infection in the large intestine, which is followed by cramps, diarrhea, and fever. The infection is usually self-limiting, but it can also cause damage to the colonic mucosa, intestinal bleeding, and death if untreated. Worldwide, Shigella spp. infections are responsible for approximately 163 million cases of dysentery and 1 million deaths each year (23). The majority of infections occur in third-world countries, where contaminated food and drinking water are common (23); however, even developed nations still have multiple Shigella outbreaks every year (47). Therefore, studying the pathogenesis of these gram-negative bacteria is of utmost importance, particularly in light of emerging antibiotic resistance, the lack of an appropriate vaccine, and the potential for use of Shigella as a bioweapon (23,33,42).Following ingestion, Shigella flexneri eventually reaches the large intestine, the target site for infection, where access to the basolateral membrane is a prerequisite for the invasion of epithelial cells (see reference 48 for a review). M cells in the large intestine phagocytose and subsequently transcytose the bacteria from the lumen to t...

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Cadaverine Prevents the Escape ofShigella flexnerifrom the Phagolysosome: A Connection between Bacterial Dissemination and Neutrophil Transepithelial Signaling

Cited by 67 publications

References 43 publications

Pathoadaptive Mutation That Mediates Adherence of Shiga Toxin-Producing Escherichia coli O111

Pathoadaptive Mutation That Mediates Adherence of Shiga Toxin-Producing Escherichia coli O111

CadA Negatively Regulates Escherichia coli O157:H7 Adherence and Intestinal Colonization

OspF and OspC1 Are Shigella flexneri Type III Secretion System Effectors That Are Required for Postinvasion Aspects of Virulence

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