Outer Membrane Protein A of
            <i>Escherichia coli</i>
            O157:H7 Stimulates Dendritic Cell Activation

Torres, Alfredo G.; Li, Yongguo; Tutt, Christopher B.; Luo, Xin; Eaves-Pyles, Tonyia; Soong, Lynn

doi:10.1128/iai.74.5.2676-2685.2006

Cited by 67 publications

(54 citation statements)

References 51 publications

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“…OmpA of Klebsiella pneumoniae has been shown to bind to and activate human macrophages and immature monocyte-derived dendritic cells in a TLR2-dependent manner (6,7). It has also been found that OmpA of Escherichia coli efficiently stimulates cytokine production by dendritic cells (8). However, the role of S. flexneri 2a OmpA in linking the innate and adaptive immune responses remains unexplored.…”

mentioning

confidence: 99%

Outer Membrane Protein A (OmpA) of Shigella flexneri 2a Links Innate and Adaptive Immunity in a TLR2-dependent Manner and Involvement of IL-12 and Nitric Oxide

Pore¹,

Mahata

Chakrabarti

2012

Journal of Biological Chemistry

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Background: OmpA activates innate immunity through TLR2, but its function and mechanism of targeting adaptive immunity remains unexplored. Results: TLR2 regulates OmpA processing and presentation, NO and cytokine release, which contributes to development of type-1 adaptive immunity. Conclusion: TLR2 is crucial to link innate and adaptive responses stimulated by OmpA. Significance: S. flexneri 2a OmpA, a novel molecule, coordinates the innate and adaptive responses.

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mentioning

confidence: 99%

Outer Membrane Protein A (OmpA) of Shigella flexneri 2a Links Innate and Adaptive Immunity in a TLR2-dependent Manner and Involvement of IL-12 and Nitric Oxide

Pore¹,

Mahata

Chakrabarti

2012

Journal of Biological Chemistry

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“…tEHEC is able to downregulate IFN-␥-induced iNOS mRNA expression and NO production in fully differentiated Caco-2 and T84 cells by suppressing the STAT-1-dependent transcription of the gene encoding iNOS following activation of the enzyme heme oxygenase 1 (208,788). In addition, it has been observed that the adhesive factor of EHEC OmpA induces IL-1, IL-10, and IL-12 cytokine production by DCs and the DC transepithelial migration across fully differentiated Caco-2 cell monolayers (789). In fully differentiated Caco-2 cells infected with EHEC, the observed tEHEC-induced downregulation of IFN-␥-induced iNOS mRNA expression and NO production (208,788,790) results from the action of its Stx in inhibiting the IFN-␥-mediated proinflammatory pathway by decreasing Stat-1 tyrosine phosphorylation (791).…”

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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“…In E. coli K1, OmpA is associated with neonatal meningitis through invasion of endothelial cells (Prasadarao et al, 1996). In E. coli O157 : H7, OmpA plays a role in adherence to intestinal epithelial cells (Torres & Kaper, 2003) and is also believed to mediate stimulation of dendritic cells to produce cytokines (Torres et al, 2006). Kuehn and co-workers demonstrated that ETEC OmpA is an outer-membrane component of native vesicles (Kesty et al, 2004).…”

Section: Leoa Interacts With Ompamentioning

confidence: 99%

Biochemical characterization of the enterotoxigenic Escherichia coli LeoA protein

Brown

Hardwidge

2007

Microbiology

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Enterotoxigenic Escherichia coli (ETEC) causes enterotoxin-induced diarrhoea and significant mortality. The molecular mechanisms underlying how the heat-labile enterotoxin (LT) is secreted during infection are poorly understood. ETEC produce outer-membrane vesicles (OMVs) containing LT that are endocytosed into host cells. Although OMV production and protein content may be a regulated component of ETEC pathogenesis, how LT loading into OMVs is regulated is unknown. The LeoA protein plays a role in secreting LT from the bacterial periplasm. To begin to understand the function of LeoA and its role in ETEC H10407 pathogenesis, a site-directed mutant lacking the putative GTP-binding domain was constructed. The ability of wild-type and mutant LeoA to hydrolyse GTP in vitro was quantified. This domain was found to be responsible for GTP binding; it is important to LeoA's function in LT secretion, and may play a modest role in the formation and protein content of OMVs. Deletion of leoA reduced the abundance of OmpX in outer-membrane protein preparations and of LT in OMVs. Immunoprecipitation experiments revealed that LeoA interacts directly with OmpA, but that the GTP-binding domain is nonessential for this interaction. Deletion of leoA rendered ETEC H10407 non-motile, through apparent periplasmic accumulation of FliC.

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Outer Membrane Protein A of Escherichia coli O157:H7 Stimulates Dendritic Cell Activation

Cited by 67 publications

References 51 publications

Outer Membrane Protein A (OmpA) of Shigella flexneri 2a Links Innate and Adaptive Immunity in a TLR2-dependent Manner and Involvement of IL-12 and Nitric Oxide

Outer Membrane Protein A (OmpA) of Shigella flexneri 2a Links Innate and Adaptive Immunity in a TLR2-dependent Manner and Involvement of IL-12 and Nitric Oxide

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

Biochemical characterization of the enterotoxigenic Escherichia coli LeoA protein

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