title: Role of phospholipase A2 and tyrosine kinase in Clostridium difficile toxin A-induced disruption of epithelial integrity, histologic inflammatory damage and intestinal secretion.
abstract: Clostridium difficile-associated disease causes diarrhea to fulminant colitis and death. We investigated the role of phospholipase A2 (PLA2) inhibitors, aristolochic acid (AA), bromophenacyl bromide (BPB) and quinacrine (QUIN) on the C. difficile toxin A-induced disruption of epithelial integrity, histologic inflammatory damage and intestinal secretion. Toxin A caused severe hemorrhagic and inflammatory fluid secretion at 6-8 h in rabbit ileal segments, an effect that was significantly inhibited by QUIN (71%, P < 0.01), AA (87%, P < 0.000l) or by BPB (51%, P < 0.01). The secretory effect of toxin A was also inhibited in segments adjacent to those with AA (89%, P < 0.01). Furthermore, QUIN or AA substantially reduced the histologic damage seen after 6-8 h in rabbit ileal segments. The cyclooxygenase inhibitor, indomethacin, also significantly inhibited (96%; n = 6) the secretory effects of toxin A in ligated rabbit intestinal segments. The destruction by toxin A of F-actin at the tight junctions of T-84 cell monolayers was not inhibited by AA or BPB. AA or QUIN had no effect on the T-84 cell tissue resistance reduction over 8-24 h after toxin A exposure. All the inhibitors were shown to be effective in the doses administered direct in ileal loops to inhibit PLA2 activity. The data suggest that PLA2 is involved in the major pathway of toxin A-induced histologic inflammatory damage and hemorrhagic fluid secretion.
authors.affiliation: Division of Infectious Diseases and International Health, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Aldo A M
authors.initials: AA
authors.lastname: Lima
authors.forename: Nilberto R F
authors.initials: NR
authors.lastname: Nascimento
authors.forename: Guodong D
authors.initials: GD
authors.lastname: Fang
authors.forename: Peter
authors.initials: P
authors.lastname: Yotseff
authors.forename: M H
authors.initials: MH
authors.lastname: Toyama
authors.forename: Richard L
authors.initials: RL
authors.lastname: Guerrant
authors.forename: Manassés C
authors.initials: MC
authors.lastname: Fonteles
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D004338:Drug Combinations; D004768:Enterotoxins / Q000633:toxicity*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007082:Ileum / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D007213:Indomethacin / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D064801:Phospholipase A2 Inhibitors; D054467:Phospholipases A2 / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D011796:Quinacrine / Q000494:pharmacology; D011817:Rabbits
chemical_list: D001427:Bacterial Toxins; D004338:Drug Combinations; D004768:Enterotoxins; D004791:Enzyme Inhibitors; D064801:Phospholipase A2 Inhibitors; C041348:tcdA protein, Clostridium difficile; D011505:Protein-Tyrosine Kinases; D054467:Phospholipases A2; D011796:Quinacrine; D007213:Indomethacin