scholarly journals Antibacterial activity of a synthetic peptide (PR-26) derived from PR-39, a proline-arginine-rich neutrophil antimicrobial peptide.

1996 ◽  
Vol 40 (1) ◽  
pp. 115-121 ◽  
Author(s):  
J Shi ◽  
C R Ross ◽  
M M Chengappa ◽  
M J Sylte ◽  
D S McVey ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Synthetic Peptide ◽  
Intestinal Epithelial Cells ◽  
Functional Domain ◽  
Gram Negative Bacteria ◽  
Intestinal Epithelial ◽  
Amino Acid Residues ◽  
Truncated Form ◽  
Gram Negative ◽  
Salmonella Choleraesuis

PR-39 is a proline-arginine-rich (PR) neutrophil antibacterial peptide originally identified and purified from the porcine small intestine. We report on the synthesis of a functional antibacterial domain of PR-39, the first 26 amino acid residues of the NH2 terminus. PR-26 was as potent as or more potent than PR-39 against enteric gram-negative bacteria. This truncated form of PR-39 potentiated neutrophil phagocytosis of Salmonella choleraesuis and decreased the level of S. typhimurium invasion into intestinal epithelial cells. Scanning electron microscopy confirmed that these peptides did not lyse cells by pore-forming mechanisms; however, they potentiated the antibacterial capabilities of a pore-forming peptide, magainin A. In addition, PR-26 was not toxic to epithelial cells at concentrations several times greater than its bactericidal concentration. These data suggest that PR-39 and its functional domain, PR-26, may potentiate the host's defense capabilities against gram-negative infections.

Transcriptomic response of immune signalling pathways in intestinal epithelial cells exposed to lipopolysaccharides, Gram-negative bacteria or potentially probiotic microbes

2012 ◽  
Vol 3 (4) ◽  
pp. 273-286 ◽  
Author(s):  
J. Audy ◽  
O. Mathieu ◽  
J. Belvis ◽  
T.A. Tompkins
Keyword(s):  
Epithelial Cells ◽  
Host Response ◽  
Intestinal Epithelial Cells ◽  
Mitogen Activated Protein Kinase ◽  
Gram Negative Bacteria ◽  
Intestinal Epithelial ◽  
Gram Positive ◽  
Transcriptomic Response ◽  
Gram Negative ◽  
The Impact

In order to understand the appropriate use of potentially probiotic Gram-positive microbes through their introduction in the gut microbiome, it is necessary to understand the influence of individual bacteria on the host-response system at a cellular level. In the present study, we have shown that lipopolysaccharides, flagellated Gram-negative bacteria, potentially probiotic Gram-positive bacteria and yeast interact differently with human intestinal epithelial cells with a custom-designed expression microarray evaluating 17 specific host-response pathways. Only lipopolysaccharides and flagellated Gram-negative bacteria induced inflammatory response, while a subset of Gram-positive microbes had anti-inflammatory potential. The main outcome from the study was the differential regulation of the central mitogen-activated protein kinase signalling pathway by these Gram-positive microbes versus commensal/pathogenic Gram-negative bacteria. The microarray was efficient to highlight the impact of individual bacteria on the response of intestinal epithelial cells, but quantitative real-time polymerase chain reaction validation demonstrated some underestimation for down-regulated genes by the microarray. This immune array will allow us to better understand the mechanisms underlying microbe-induced host immune responses.

Flagellin-induced tolerance of the Toll-like receptor 5 signaling pathway in polarized intestinal epithelial cells

2007 ◽  
Vol 292 (3) ◽  
pp. G767-G778 ◽  
Author(s):  
Jun Sun ◽  
Pamela E. Fegan ◽  
Anjali S. Desai ◽  
James L. Madara ◽  
Michael E. Hobert
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Prior Exposure ◽  
Intestinal Epithelial ◽  
Toll Like Receptor ◽  
Proinflammatory Response ◽  
Gram Negative ◽  
Human Intestinal Epithelial Cells ◽  
Induced Tolerance ◽  
Toll Like Receptor 5

Salmonella typhimurium is a gram-negative enteric pathogen that invades the mucosal epithelium and is associated with diarrheal illness in humans. Flagellin from S. typhimurium and other gram-negative bacteria has been shown to be the predominant proinflammatory mediator through activation of the basolateral Toll-like receptor 5 (TLR5). Recent evidence has shown that prior exposure can render immune cells tolerant to subsequent challenges by TLR ligands. Accordingly, we examined whether prior exposure to purified flagellin would render human intestinal epithelial cells insensitive to future contact. We found that flagellin-induced tolerance is common to polarized epithelial cells and prevents further activation of proinflammatory signaling cascades by both purified flagellin and Salmonella bacteria but does not affect TNF-α stimulation of the same pathways. Flagellin tolerance is a rapid process that does not require protein synthesis, and that occurs within 1 to 2 h of flagellin exposure. Prolonged flagellin exposure blocks activation of the NF-κB, MAPK, and phosphoinositol 3-kinase signaling pathways and results in the internalization of a fraction of the basolateral TLR5 without affecting the polarity or total expression of TLR5. After removal of flagellin, cells require more than 24 h to fully recover their ability to mount a normal proinflammatory response. We have found that activation of phosphoinositol 3-kinase and Akt by flagellin has a small damping effect in the early stages of flagellin signaling but is not responsible for tolerance. Our study indicates that inhibition of TLR5-associated IL-1 receptor-associated kinase-4 activity occurs during the development of flagellin tolerance and is likely to be the cause of tolerance.

scholarly journals Crosstalk Between Nuclear Glucose-Regulated Protein 78 and Tumor Protein 53 Contributes to the Lipopolysaccharide Aggravated Apoptosis of Endoplasmic Reticulum Stress-Responsive Porcine Intestinal Epithelial Cells

2018 ◽  
Vol 48 (6) ◽  
pp. 2441-2455 ◽  
Author(s):  
Qian Jiang ◽  
Gang Liu ◽  
Jiashun Chen ◽  
Kang Yao ◽  
Yulong Yin
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Endoplasmic Reticulum Stress ◽  
Intestinal Inflammation ◽  
Intestinal Epithelial Cells ◽  
Intestinal Cells ◽  
Intestinal Epithelial ◽  
Gram Negative ◽  
Rna Transfection ◽  
Glucose Regulated Protein

Background/Aims: Lipopolysaccharides (LPSs) act as virulence factors that trigger intestinal inflammation and thereby compromise the production of pigs worldwide. Intestinal diseases and dysfunction have been attributed to endoplasmic reticulum stress (ERS) and the subsequent apoptosis of intestinal epithelial cells. Therefore It is important to explore whether LPSs aggravate ERS-mediated apoptosis of intestinal epithelial cells. Methods: ERS and inflammation models were established in porcine cell line J2 (IPEC-J2) and the cells were treated with tunicamycin or LPS at specific times. The expression of marker proteins was determined by western blot and immunofluorescence. Possible crosstalk between proteins was analyzed by co-immunoprecipitation. Small interfering RNA transfection was employed to verify the mechanisms. Results: We found that Escherichia coli-derived LPS aggravated ERS and ERS-mediated apoptosis in ERS-responsive IPEC-J2 cells. The crosstalk between nuclear glucose-regulated protein 78 (GRP78) and tumor protein 53 (p53) was verified to trigger this LPS-aggravated apoptosis of ERS-responsive intestinal cells. Conclusion: This novel finding implies that intestinal malfunctions might solely originate from the effects of Gram-negative bacteria on ERS-responsive intestinal cells. The regulation of ERS signaling (especially the crosstalk between nuclear GRP78 and p53) in ERS-responsive/rapidly growing intestines may help intestinal cells survive from Gram-negative bacterial infections.

scholarly journals Nod1 Is an Essential Signal Transducer in Intestinal Epithelial Cells Infected with Bacteria That Avoid Recognition by Toll-Like Receptors

2004 ◽  
Vol 72 (3) ◽  
pp. 1487-1495 ◽  
Author(s):  
Jae Gyu Kim ◽  
Sung Joong Lee ◽  
Martin F. Kagnoff
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelium ◽  
Mammalian Cells ◽  
Target Genes ◽  
Intestinal Epithelial Cells ◽  
Enteric Bacteria ◽  
Intestinal Epithelial ◽  
Gram Negative ◽  
Iκb Kinase ◽  
Human Intestinal Epithelial Cells

ABSTRACT The transcription factor NF-κB in human intestinal epithelial cells plays a central role in regulating genes that govern the onset of mucosal inflammatory responses following intestinal microbial infection. Nod1 is a cytosolic pattern recognition receptor in mammalian cells that senses components of microbial peptidoglycans and signals the activation of NF-κB. The aim of these studies was to assess the functional importance of Nod1 in activating NF-κB and NF-κB proinflammatory target genes in human intestinal epithelium. Human colon epithelial cells that constitutively express Nod1 were used as a model intestinal epithelium. These cells do not signal through Toll-like receptor 4 (TLR4) or respond to bacterial lipopolysaccharide, but they express functional TLR5 and interleukin 1 (IL-1) receptors that signal the activation of NF-κB in response to bacterial flagellin or IL-1 stimulation. Stable expression of dominant negative (DN) Nod1 in colon epithelial cells prevented IκB kinase and NF-κB activation in response to infection with enteroinvasive Escherichia coli. In contrast, DN Nod1 did not eliminate IL-1 or flagellin-stimulated NF-κB activation. Inhibition of NF-κB was accompanied by inhibition of NF-κB target genes that provide signals for the mucosal influx of neutrophils during intestinal infection. We conclude that signaling through Nod1 is required for activating NF-κB in human intestinal epithelial cells infected with gram-negative enteric bacteria that can bypass TLR activation. Signaling through Nod1 provides the intestinal epithelium with a backup mechanism for rapidly activating innate immunity during infection with a group of highly invasive pathogenic gram-negative bacteria.

Three-dimensional organization and functional relationships of endocytotic compartments in pig intestinal epithelial cells

1992 ◽  
Vol 50 (1) ◽  
pp. 576-577
Author(s):  
Julian P. Heath ◽  
Buford L. Nichols ◽  
László G. Kömüves
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Three Dimensional ◽  
Intestinal Epithelial ◽  
Cell Surfaces ◽  
Basal Surface ◽  
Functional Relationships

The newborn pig intestine is adapted for the rapid and efficient absorption of nutrients from colostrum. In enterocytes, colostral proteins are taken up into an apical endocytotic complex of channels that transports them to target organelles or to the basal surface for release into the circulation. The apical endocytotic complex of tubules and vesicles clearly is a major intersection in the routes taken by vesicles trafficking to and from the Golgi, lysosomes, and the apical and basolateral cell surfaces.Jejunal tissues were taken from piglets suckled for up to 6 hours and prepared for electron microscopy and immunocytochemistry as previously described.

Sign in / Sign up

Export Citation Format

Share Document