scholarly journals The NleE/OspZ Family of Effector Proteins Is Required for Polymorphonuclear Transepithelial Migration, a Characteristic Shared by Enteropathogenic Escherichia coli and Shigella flexneri Infections

2007 ◽  
Vol 76 (1) ◽  
pp. 369-379 ◽  
Author(s):  
Daniel V. Zurawski ◽  
Karen L. Mumy ◽  
Luminita Badea ◽  
Julia A. Prentice ◽  
Elizabeth L. Hartland ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Deletion Mutant ◽  
Intestinal Epithelial Cells ◽  
Shigella Flexneri ◽  
Host Cells ◽  
Apical Surface ◽  
Intestinal Epithelial ◽  
Wild Type ◽  
Secretion Systems

ABSTRACT Enteropathogenic Escherichia coli (EPEC) and Shigella flexneri are human host-specific pathogens that infect intestinal epithelial cells. However, each bacterial species employs a different infection strategy within this environmental niche. EPEC attaches to the apical surface of small intestine enterocytes, causing microvillus effacement and rearrangement of the host cell cytoskeleton beneath adherent bacteria. In contrast, S. flexneri invades the large intestine epithelium at the basolateral membrane, replicates, and spreads cell to cell. Both EPEC and S. flexneri rely on type three secretion systems (T3SS) to secrete effectors into host cells, and both pathogens recruit polymorphonuclear leukocytes (PMNs) from the submucosa to the lumen of the intestine. In this report, we compared the virulence functions of the EPEC T3SS effector NleE and the homologous Shigella protein Orf212. We discovered that Orf212 was secreted by the S. flexneri T3SS and renamed this protein OspZ. Infection of polarized T84 intestinal epithelial cells with an ospZ deletion mutant of S. flexneri resulted in reduced PMN transepithelial migration compared to infection by the wild type. An nleE deletion mutant of EPEC showed a similar reduction of PMN migration. The ability to induce PMN migration was restored in both mutants when either ospZ or nleE was expressed from a plasmid. An infection of T84 cells with the ΔospZ mutant resulted in reduced extracellular signal-related kinase phosphorylation and NF-κB activation compared to infection with the wild type. Therefore, we conclude that OspZ and NleE have similar roles in the upstream induction of host signaling pathways required for PMN transepithelial migration in Shigella and EPEC infections.

OmpD but not OmpC is involved in adherence ofSalmonella entericaserovar Typhimurium to human cells

2004 ◽  
Vol 50 (9) ◽  
pp. 719-727 ◽  
Author(s):  
Bochiwe Hara-Kaonga ◽  
Thomas G Pistole
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Human Cells ◽  
Host Cells ◽  
Intestinal Epithelial ◽  
Wild Type ◽  
Human Macrophages ◽  
Significant Difference ◽  
Serovar Typhimurium

Conflicting reports exist regarding the role of porins OmpC and OmpD in infections due to Salmonella enterica serovar Typhimurium. This study investigated the role of these porins in bacterial adherence to human macrophages and intestinal epithelial cells. ompC and ompD mutant strains were created by transposon mutagenesis using P22-mediated transduction of Tn10 and Tn5 insertions, respectively, into wild-type strain 14028. Fluorescein-labeled wild-type and mutant bacteria were incubated with host cells at various bacteria to cell ratios for 1 h at 37 °C and analyzed by flow cytometry. The mean fluorescence intensity of cells with associated wild-type and mutant bacteria was used to estimate the number of bacteria bound per host cell. Adherence was also measured by fluorescence microscopy. Neither assay showed a significant difference in binding of the ompC mutant and wild-type strains to the human cells. In contrast, the ompD mutant exhibited lowered binding to both cell types. Our findings suggest that OmpD but not OmpC is involved in the recognition of Salmonella serovar Typhimurium by human macrophages and intestinal epithelial cells.Key words: Salmonella, adherence, porins, intestinal epithelial cells, macrophage.

Efficacy of Plant-Derived Antimicrobials in Controlling Enterohemorrhagic Escherichia coli Virulence In Vitro

2016 ◽  
Vol 79 (11) ◽  
pp. 1965-1970 ◽  
Author(s):  
SANGEETHA ANANDA BASKARAN ◽  
ANUP KOLLANOOR-JOHNY ◽  
MEERA SURENDRAN NAIR ◽  
KUMAR VENKITANARAYANAN
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Antimicrobial Agents ◽  
Intestinal Epithelial Cells ◽  
Enterohemorrhagic Escherichia Coli ◽  
Host Cells ◽  
Intestinal Epithelial ◽  
Virulence Gene Expression ◽  
Human Intestinal Epithelial Cells

ABSTRACTEscherichia coli O157:H7 is a major foodborne pathogen that can cause serious human illness characterized by hemorrhagic diarrhea and kidney failure. The pathology of enterohemorrhagic E. coli O157:H7 (EHEC) infection is primarily mediated by verotoxins, which bind to the globotriaosylceramide receptor on host cells. Antibiotics are contraindicated for treating EHEC infection because they lead to increased verotoxin release, thereby increasing the risk of renal failure and death in patients. Thus, alternative strategies are needed for controlling EHEC infections in humans. This study investigated the effect of subinhibitory concentrations of five plant-derived antimicrobial agents (PDAs) that are generally considered as safe, i.e., trans-cinnamaldehyde, eugenol, carvacrol, thymol, and β-resorcylic acid, on EHEC motility, adhesion to human intestinal epithelial cells, verotoxin production, and virulence gene expression. All tested PDAs reduced EHEC motility and attachment to human intestinal epithelial cells (P < 0.05) and decreased verotoxin synthesis by EHEC. The reverse transcription real-time PCR data revealed that PDAs decreased the expression of critical virulence genes in EHEC (P < 0.05). The results collectively suggest that these PDAs could be used to reduce EHEC virulence, but follow-up studies in animal models are necessary to validate these findings.

scholarly journals Verotoxin 2 Enhances Adherence of Enterohemorrhagic Escherichia coli O157:H7 to Intestinal Epithelial Cells and Expression of β1-Integrin by IPEC-J2 Cells

2010 ◽  
Vol 76 (13) ◽  
pp. 4461-4468 ◽  
Author(s):  
Bianfang Liu ◽  
Xianhua Yin ◽  
Yanni Feng ◽  
James R. Chambers ◽  
Aiguang Guo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Human Colon ◽  
Enterohemorrhagic Escherichia Coli ◽  
Β1 Integrin ◽  
Intestinal Epithelial ◽  
Wild Type ◽  
O157 Strain ◽  
Human Laryngeal Carcinoma

ABSTRACT Verotoxin (VT) has been implicated in the promotion of adherence to and colonization of intestinal epithelial cells by enterohemorrhagic Escherichia coli (EHEC) O157:H7. The present study investigated the effect of VT2 on the adherence of EHEC O157:H7 strain 86-24 to porcine jejunal (IPEC-J2), human colon (CaCo-2), and human laryngeal carcinoma (HEp-2) cell lines and on the expression in IPEC-J2 cells of synthases for β1-integrin and nucleolin, both of which are implicated in bacterial adherence. The effect on expression of globotriaosylceramide (Gb3) synthase, the receptor for VT, was also examined. Data were obtained by adherence assays and quantitative reverse transcriptase PCR, using EHEC O157 strain 86-24, a vt2 deletion mutant, a vt2 phage-negative strain, and complemented mutants in which the vt2 gene was restored. Compared with the adherence of the parent and complemented mutant strains, the vt2-negative strains adhered significantly less to all three types of cells. Adherence of the wild-type EHEC strain to IPEC-J2 cells was accompanied by increased expression of β1-integrin, nucleolin, and Gb3 synthase. IPEC-J2 cells in association with wild-type EHEC O157:H7 or the complemented mutants expressed higher levels of β1-integrin than did cells in association with the vt2-negative strains or with no bacteria. Expression of nucleolin was decreased by association with the vt2-negative mutant, but complementation failed to restore wild-type expression. The data indicate that VT2 plays a role in the adherence of EHEC O157:H7 to intestinal epithelial cells, possibly by increasing the expression of the host receptor β1-integrin.

scholarly journals Salmonella Typhimurium induces NAIP/NLRC4- and NLRP3/ASC-independent, caspase-1/4-dependent inflammasome activation in human intestinal epithelial cells

2021 ◽  
Author(s):  
Nawar Naseer ◽  
Renate Bauer ◽  
Jenna Zhang ◽  
Igor E. Brodsky ◽  
Isabella Rauch ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Adaptor Protein ◽  
Host Cells ◽  
Intestinal Lumen ◽  
Bacterial Invasion ◽  
Inflammasome Activation ◽  
Intestinal Epithelial ◽  
Secretion Systems ◽  
Caspase 1

Salmonella enterica serovar Typhimurium is a gram-negative pathogen that causes diseases ranging from gastroenteritis to systemic infection and sepsis. Salmonella uses type III secretion systems (T3SSs) to inject effectors into host cells. While these effectors are necessary for bacterial invasion and intracellular survival, intracellular delivery of T3SS products also enables detection of Salmonella by cytosolic immune sensors. Upon detecting translocated Salmonella ligands, these sensors form multimeric complexes called inflammasomes, which activate caspases that lead to proinflammatory cytokine release and pyroptosis. In particular, the Salmonella T3SS needle, inner rod, and flagellin proteins activate the NAIP/NLRC4 inflammasome in murine intestinal epithelial cells (IECs), which leads to restriction of bacterial replication and extrusion of infected IECs into the intestinal lumen, thereby preventing systemic dissemination of Salmonella . While these processes are studied quite well in mice, the role of the NAIP/NLRC4 inflammasome in human IECs remains unknown. Unexpectedly, we found the NAIP/NLRC4 inflammasome is dispensable for early inflammasome responses to Salmonella in both human intestinal epithelial cell lines and organoids. Additionally, the NLRP3 inflammasome and the adaptor protein ASC are not required for inflammasome activation in Caco-2 cells. Instead, we observed a partial requirement for caspase-1, and a necessity for caspase-4 and GSDMD pore-forming activity in mediating inflammasome responses to Salmonella in Caco-2 cells. These findings suggest that unlike murine IECs, human IECs do not rely on NAIP/NLRC4, and also do not use NLRP3/ASC. Instead, they primarily use caspases-1 and -4 to mediate early inflammasome responses to SPI-1-expressing Salmonella .

scholarly journals Role of Decreased Levels of Fis Histone-Like Protein in Crohn's Disease-Associated Adherent Invasive Escherichia coli LF82 Bacteria Interacting with Intestinal Epithelial Cells

2010 ◽  
Vol 192 (7) ◽  
pp. 1832-1843 ◽  
Author(s):  
Sylvie Miquel ◽  
Laurent Claret ◽  
Richard Bonnet ◽  
Imen Dorboz ◽  
Nicolas Barnich ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Host Cells ◽  
Intestinal Epithelial ◽  
Type 1 Pili

ABSTRACT The interaction of Crohn's disease (CD)-associated adherent-invasive Escherichia coli (AIEC) strain LF82 with intestinal epithelial cells depends on surface appendages, such as type 1 pili and flagella. Histone-like proteins operate as global regulators to control the expression of these virulence factors. We evaluated the role of histone-like proteins in AIEC reference strain LF82 during infection of intestinal epithelial cells, Intestine-407, and observed that the fis mRNA level was decreased. The role of Fis in AIEC LF82 was determined by studying the phenotype of an LF82 fis::Km mutant. This was the first mutant of strain LF82 that has been described thus far that is unable to express flagellin but still able to produce type 1 pili. The cyclic-di-GMP pathway linking flagella and type 1 pilus expression is not involved in Fis-mediated regulation, and we identified in the present study Fis-binding sites located upstream of the fimE gene and in the intergenic region between fimB and nanC of the fim operon encoding type 1 pili. The major consequence of decreased Fis expression in AIEC bacteria in contact with host cells is a direct downregulation of fimE expression, leading to the preferential ON phase of the fimS element. Thus, by maintaining type 1 pilus expression, AIEC bacteria, which interact with the gut mucosa, have greater ability to colonize and to induce inflammation in CD patients.

scholarly journals The Enteropathogenic Escherichia coli-Secreted Protein EspZ Inhibits Host Cell Apoptosis

2012 ◽  
Vol 80 (11) ◽  
pp. 3850-3857 ◽  
Author(s):  
Jennifer Lising Roxas ◽  
John Scott Wilbur ◽  
Xiangfeng Zhang ◽  
Giovanna Martinez ◽  
Gayatri Vedantam ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Host Cell ◽  
Signaling Pathways ◽  
Intestinal Epithelial Cells ◽  
Host Cells ◽  
Intestinal Epithelial ◽  
Apoptotic Pathway ◽  
Host Signaling ◽  
Infected Cells

ABSTRACTThe diarrheagenic pathogen enteropathogenicEscherichia coli(EPEC) limits the death of infected enterocytes early in infection. A number of bacterial molecules and host signaling pathways contribute to the enhanced survival of EPEC-infected host cells. EspZ, a type III secreted effector protein that is unique to EPEC and related “attaching and effacing” (A/E) pathogens, plays a role in limiting host cell death, but the precise host signaling pathways responsible for this phenotype are not known. We hypothesized that EspZ contributes to the survival of infected intestinal epithelial cells by interfering with apoptosis. Consistent with previous studies, scanning electron microscopy analysis of intestinal epithelial cells infected with an EPECespZmutant (ΔespZ) showed increased levels of apoptotic and necrotic cells compared to cells infected with the isogenic parent strain. Correspondingly, higher levels of cytosolic cytochromecand increased activation of caspases 9, 7, and 3 were observed for ΔespZstrain-infected cells compared to wild-type (WT) EPEC-infected cells. Finally,espZ-transfected epithelial cells were significantly protected from staurosporine-induced, but not tumor necrosis factor alpha (TNF-α)/cycloheximide-induced, apoptosis. Thus, EspZ contributes to epithelial cell survival by mechanisms that include the inhibition of the intrinsic apoptotic pathway. The enhanced survival of infected enterocytes by molecules such as EspZ likely plays a key role in optimal colonization by A/E pathogens.

scholarly journals Expression of lysophosphatidic acid receptor 5 is necessary for the regulation of intestinal Na+/H+ exchanger 3 by lysophosphatidic acid in vivo

2018 ◽  
Vol 315 (4) ◽  
pp. G433-G442 ◽  
Author(s):  
Kayte A. Jenkin ◽  
Peijian He ◽  
C. Chris Yun
Keyword(s):  
Epithelial Cells ◽  
Lysophosphatidic Acid ◽  
Direct Evidence ◽  
Intestinal Epithelial Cells ◽  
Regulatory Role ◽  
Intestinal Epithelial ◽  
Fluid Absorption ◽  
Wild Type

Lysophosphatidic acid (LPA) is a bioactive lipid molecule, which regulates a broad range of pathophysiological processes. Recent studies have demonstrated that LPA modulates electrolyte flux in the intestine, and its potential as an antidiarrheal agent has been suggested. Of six LPA receptors, LPA5 is highly expressed in the intestine. Recent studies by our group have demonstrated activation of Na+/H+ exchanger 3 (NHE3) by LPA5. However, much of what has been elucidated was achieved using colonic cell lines that were transfected to express LPA5. In the current study, we engineered a mouse that lacks LPA5 in intestinal epithelial cells, Lpar5ΔIEC, and investigated the role of LPA5 in NHE3 regulation and fluid absorption in vivo. The intestine of Lpar5ΔIEC mice appeared morphologically normal, and the stool frequency and fecal water content were unchanged compared with wild-type mice. Basal rates of NHE3 activity and fluid absorption and total NHE3 expression were not changed in Lpar5ΔIEC mice. However, LPA did not activate NHE3 activity or fluid absorption in Lpar5ΔIEC mice, providing direct evidence for the regulatory role of LPA5. NHE3 activation involves trafficking of NHE3 from the terminal web to microvilli, and this mobilization of NHE3 by LPA was abolished in Lpar5ΔIEC mice. Dysregulation of NHE3 was specific to LPA, and insulin and cholera toxin were able to stimulate and inhibit NHE3, respectively, in both wild-type and Lpar5ΔIEC mice. The current study for the first time demonstrates the necessity of LPA5 in LPA-mediated stimulation of NHE3 in vivo. NEW & NOTEWORTHY This study is the first to assess the role of LPA5 in NHE3 regulation and fluid absorption in vivo using a mouse that lacks LPA5 in intestinal epithelial cells, Lpar5ΔIEC. Basal rates of NHE3 activity and fluid absorption, and total NHE3 expression were not changed in Lpar5ΔIEC mice. However, LPA did not activate NHE3 activity or fluid absorption in Lpar5ΔIEC mice, providing direct evidence for the regulatory role of LPA5.

scholarly journals Study on effect of anti-diarrheal medicinal plants on enteropathogenic Escherichia coli induced interleukin-8 secretion by intestinal epithelial cells

2011 ◽  
Vol 1 (1) ◽  
pp. 16 ◽  
Author(s):  
S. Brijesh ◽  
Pundarikakshudu Tetali ◽  
Tannaz J. Birdi
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Medicinal Plants ◽  
Inflammatory Responses ◽  
Intestinal Epithelial Cells ◽  
Colon Adenocarcinoma ◽  
Cyperus Rotundus ◽  
Health Concern ◽  
Intestinal Epithelial ◽  
Infantile Diarrhea

Diarrhea is a major health concern in developing countries with enteropathogenic <em>Escherichia coli</em> (EPEC) being a leading cause of infantile diarrhea. Much of the pathology of EPEC infection is due to the inflammatory responses of infected intestinal epithelium through secretion of pro-inflammatory cytoki - nes such as interleukin (IL)-8. With medicinal plants gaining popularity as prospective antidiarrheal agents, we aimed to evaluate the effect of anti-diarrheal medicinal plants on secretion of IL-8 by epithelial cells in response to EPEC infection. The effect of the decoctions of four anti-diarrheal medicinal plants viz. <em>Aegle marmelos</em>, <em>Cyperus rotundus</em>, <em>Psidium guajava</em> and <em>Zingiber officinale</em> was studied on secretion of IL-8 by a human colon adenocarcinoma cell line, HT-29 infected with <em>E. coli </em>E2348/69. Two protocols were used viz. pre-incubation and post-incubation. The data obtained demonstrated that out of the four plants used, only <em>P. guajava</em> decreased secretion of IL-8 in the post-incubation protocol although in the pre-incubation protocol an increase was observed. A similar increase was seen with <em>C. rotundus</em> in the preincubation protocol. No effect on IL-8 secretion was observed with <em>A. marmelos</em> and <em>Z. officinale</em> in both protocols and with <em>C. rotundus </em>in the post-incubation protocol. The post-incubation protocol, in terms of clinical relevance, indicates the effect of the plant decoctions when used as treatment. Hence <em>P. guajava</em> may be effective in controlling the acute inflammatory response of the intestinal epithelial cells in response to EPEC infection.<p> </p>

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