title: Feedback effects of host-derived adenosine on enteropathogenic Escherichia coli.
abstract: Enteropathogenic E. coli (EPEC) is a common cause of diarrhea in children in developing countries. After adhering to intestinal cells, EPEC secretes effector proteins into host cells, causing cell damage and eventually death. We previously showed that EPEC infection triggers the release of ATP from host cells and that ATP is broken down to ADP, AMP, and adenosine. Adenosine produced from the breakdown of extracellular ATP triggers fluid secretion in intestinal monolayers and may be an important mediator of EPEC-induced diarrhea. Here we examined whether adenosine has any effects on EPEC bacteria. Adenosine stimulated EPEC growth in several types of media in vitro. Adenosine also altered the pattern of EPEC adherence to cultured cells from a localized adherence pattern to a more diffuse pattern. Adenosine changed the expression of virulence factors in EPEC, inhibiting the expression of the bundle-forming pilus (BFP) and enhancing expression of the EPEC secreted proteins (Esps). In vivo, experimental manipulations of adenosine levels had strong effects on the outcome of EPEC infection in rabbit intestinal loops. In addition to its previously reported effects on host tissues, adenosine has strong effects on EPEC bacteria, stimulating EPEC growth, altering its adherence pattern, and changing the expression of several important virulence genes. Adenosine, like noradrenaline, is a small, host-derived molecule that is utilized as a signal by EPEC.
authors.affiliation: Department of Medicine, Division of Infectious Diseases, University at Buffalo, Buffalo, NY 14214, USA. jcrane@acsu.buffalo.edu
authors.forename: John K
authors.initials: JK
authors.lastname: Crane
authors.forename: Irina
authors.initials: I
authors.lastname: Shulgina
mesh_terms: D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D001422:Bacterial Adhesion / Q000187:drug effects; D002460:Cell Line; D054308:Enteropathogenic Escherichia coli / Q000187:drug effects* / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000096:biosynthesis; D025461:Feedback, Physiological; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006801:Humans; D007082:Ileum / Q000382:microbiology; D011817:Rabbits; D037521:Virulence Factors / Q000096:biosynthesis
chemical_list: D029968:Escherichia coli Proteins; D037521:Virulence Factors; D000241:Adenosine