Heme oxygenase-1 is a critical regulator of nitric oxide production in enterohemorrhagic Escherichia coli-infected human enterocytes
PubMed ID
18390757
Abstract
Enterohemorrhagic Escherichia coli (EHEC) are the causative agent of hemolytic-uremic syndrome. In the first stage of the infection, EHEC interact with human enterocytes to modulate the innate immune response. Inducible NO synthase (iNOS)-derived NO is a critical mediator of the inflammatory response of the infected intestinal mucosa. We therefore aimed to analyze the role of EHEC on iNOS induction in human epithelial cell lines. In this regard, we show that EHEC down-regulate IFN-gamma-induced iNOS mRNA expression and NO production in Hct-8, Caco-2, and T84 cells. This inhibitory effect occurs through the decrease of STAT-1 activation. In parallel, we demonstrate that EHEC stimulate the rapid inducible expression of the gene hmox-1 that encodes for the enzyme heme oxygenase-1 (HO-1). Knock-down of hmox-1 gene expression by small interfering RNA or the blockade of HO-1 activity by zinc protoporphyrin IX abrogated the EHEC-dependent inhibition of STAT-1 activation and iNOS mRNA expression in activated human enterocytes. These results highlight a new strategy elaborated by EHEC to control the host innate immune response.
Date Issued
2008
Publication Type
Article
Language(s)
en
Author(s)
Rannou, François | |
Thélier, Natacha | |
Glasser, Anne-Lise | |
de Sablet, Thibaut | |
Martin, Christine | |
Gobert, Alain P |
Additional Credits
Journal
Journal of immunology
Publisher
American Association of Immunologists
ISSN
0022-1767
ISBN
18390757
Access(Rights)
metadata.only