P005. Enterohaemorrhagic Escherichia coli inhibit iNOS expression in activated human intestinal epithelial cells

Nitric Oxide ◽  
2006 ◽  
Vol 14 (4) ◽  
pp. 18
Author(s):  
Marjolaine Vareille ◽  
Thibaut de Sablet ◽  
Alexandra Durand ◽  
Christine Martin ◽  
Alain P. Gobert
2010 ◽  
Vol 1 (3) ◽  
pp. 283-295 ◽  
Author(s):  
H. Putaala ◽  
R. Barrangou ◽  
G. Leyer ◽  
A. Ouwehand ◽  
E. Bech Hansen ◽  
...  

The complex microbial population residing in the human gastrointestinal tract consists of commensal, potential pathogenic and beneficial species, which are probably perceived differently by the host and consequently could be expected to trigger specific transcriptional responses. Here, we provide a comparative analysis of the global in vitro transcriptional response of human intestinal epithelial cells to Lactobacillus acidophilus NCFM™, Lactobacillus salivarius Ls-33, Bifidobacterium animalis subsp. lactis 420, and enterohaemorrhagic Escherichia coli O157:H7 (EHEC). Interestingly, L. salivarius Ls-33 DCE-induced changes were overall more similar to those of B. lactis 420 than to L. acidophilus NCFM™, which is consistent with previously observed in vivo immunomodulation properties. In the gene ontology and pathway analyses both specific and unspecific changes were observed. Common to all was the regulation of apoptosis and adipogenesis, and lipid-metabolism related regulation by the probiotics. Specific changes such as regulation of cell-cell adhesion by B. lactis 420, superoxide metabolism by L. salivarius Ls-33, and regulation of MAPK pathway by L. acidophilus NCFM™ were noted. Furthermore, fundamental differences were observed between the pathogenic and probiotic treatments in the Toll-like receptor pathway, especially for adapter molecules with a lowered level of transcriptional activation of MyD88, TRIF, IRAK1 and TRAF6 by probiotics compared to EHEC. The results in this study provide insights into the relationship between probiotics and human intestinal epithelial cells, notably with regard to strain-specific responses, and highlight the differences between transcriptional responses to pathogenic and probiotic bacteria.


2016 ◽  
Vol 79 (11) ◽  
pp. 1965-1970 ◽  
Author(s):  
SANGEETHA ANANDA BASKARAN ◽  
ANUP KOLLANOOR-JOHNY ◽  
MEERA SURENDRAN NAIR ◽  
KUMAR VENKITANARAYANAN

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.


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