Inhibition of Shigella flexneri-induced transepithelial migration of polymorphonuclear leucocytes by cadaverine

McCormick, Beth A.; Fernandez, M. Isabel; Siber, Andrew M.; Maurelli, Anthony T.

doi:10.1046/j.1462-5822.1999.00014.x

Cited by 57 publications

(43 citation statements)

References 41 publications

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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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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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“…It is not known whether their O111:H Ϫ isolate lacked the LDC system. The role of the cad operon in virulence expression and as an inducible system that responds to environmental factors was first elucidated by Maurelli et al, who found that introduction of cadA in Shigella flexneri 2a causes attenuation of its virulence and inhibition of enterotoxin production (32) and showed that cadaverine had an effect on the migration of polymorphonuclear leukocytes across the intestinal epithelial monolayers as well as inducing compartmentalization of Shigella species to the phagolysosome (18,33). Furthermore, they revealed that the lack of LDC activity in Shigella strains is due to a large chromosomal deletion up to 90 kb in the vicinity of the cadA gene (16) and proposed that the presence of "black holes" is a mechanism which provides an evolutionary advantage enabling S. flexneri to increase its pathogenic potential in host tissues.…”

Section: Discussionmentioning

confidence: 99%

“…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%

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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“…One hundred microliters of a stationary-phase culture was used to inoculate 10 ml of TSB, and the bacteria were grown in a shaking incubator for approximately 2 h at 37°C to the mid-exponential phase (optical density at 600 nm of 0.30). Trypticase soy agar is TSB containing 15 g of Bacto agar per liter (Difco Laboratories) (32,33).…”

Section: Methodsmentioning

confidence: 99%

Shigella flexneriInteractions with the Basolateral Membrane Domain of Polarized Model Intestinal Epithelium: Role of Lipopolysaccharide in Cell Invasion and in Activation of the Mitogen-Activated Protein Kinase ERK

2002

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An early step governing Shigella flexneri pathogenesis is the invasion of the colonic epithelium from the basolateral surface followed by disruption of the colonic epithelial barrier. Despite recent insight into S. flexneri-host interactions, much remains to be determined regarding the nature of the initial contact between S. flexneri and the host epithelial basolateral membrane domain. Since the lipopolysaccharide (LPS) is located at the outermost part of the bacterial membrane, we considered that this component might be used by S. flexneri to attach to the basolateral surface of the intestinal epithelium and promote a proinflammatory response. Therefore, polarized human T84 intestinal epithelial cells were infected from the basolateral surface with either wild-type S. flexneri or one of its isogenic LPS-defective strains with mutations in either rfc, rfaL, or galU. We found that both adherence to and internalization into the basolateral surface of a polarized intestinal epithelium with S. flexneri were highly dependent on the length of the LPS (i.e., rfc > rfaL > galU). Furthermore, the addition of the anti-inflammatory LPS (RsDPLA) considerably decreased the invasion profile of wild-type S. flexneri by nearly 50%. Since LPS is associated with host inflammation, we further examined whether this molecule was involved in Shigella-induced inflammatory events. We found that S. flexneri LPS plays an important role in mediating epithelial-derived signaling, which leads to directed migration of polymorphonuclear leukocytes across model intestinal epithelium. This signaling most likely involves the activation of the mitogen-activated protein kinase extracellular regulated kinase. Thus, our findings have important implications on the understanding of the mechanisms by which S. flexneri can elicit mucosal inflammation.Shigella spp. are a group of gram-negative enteric bacilli that cause acute bacillary dysentery in humans. The syndrome caused by Shigella consists of painful abdominal cramps, nausea, and fever, along with blood and mucus in the stool. In its most severe forms, shigellosis is associated with an intense inflammatory reaction that leads to the destruction of the colonic mucosa (4). The ability of this food-borne pathogen to invade and colonize the colonic epithelium is a key determinant in the establishment of the disease. Following entry into epithelial cells from the basolateral surface (35), Shigella flexneri lyses the primary vacuole and multiplies within the host cytoplasm. Dissemination occurs by both intracellular and intercellular spreading and results in the formation of "fingerlike" protrusions that extend from infected cells and are endocytosed by adjacent cells (1,9,18,47,51). Thus, since Shigella can spread in cell monolayers without extracellular steps, these organisms are typically confined to the epithelial layer of the colonic mucosa.The histopathology of shigellosis is defined by diffuse erythema, swelling of the mucosa, focal hemorrhages, and a purulent exudate. This response is largely c...

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Inhibition of Shigella flexneri-induced transepithelial migration of polymorphonuclear leucocytes by cadaverine

Cited by 57 publications

References 41 publications

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

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

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

Shigella flexneriInteractions with the Basolateral Membrane Domain of Polarized Model Intestinal Epithelium: Role of Lipopolysaccharide in Cell Invasion and in Activation of the Mitogen-Activated Protein Kinase ERK

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