title: Zonula occludens toxin modulates tight junctions through protein kinase C-dependent actin reorganization, in vitro.
abstract: The intracellular signaling involved in the mechanism of action of zonula occludens toxin (ZOT) was studied using several in vitro and ex vivo models. ZOT showed a selective effect among various cell lines tested, suggesting that it may interact with a specific receptor, whose surface expression on various cells differs. When tested in IEC6 cell monolayers, ZOT-containing supernatants induced a redistribution of the F-actin cytoskeleton. Similar results were obtained with rabbit ileal mucosa, where the reorganization of F-actin paralleled the increase in tissue permeability. In endothelial cells, the cytoskeletal rearrangement involved a decrease of the soluble G-actin pool (-27%) and a reciprocal increase in the filamentous F-actin pool (+22%). This actin polymerization was time- and dose-dependent, and was reversible. Pretreatment with a specific protein kinase C inhibitor, CGP41251, completely abolished the ZOT effects on both tissue permeability and actin polymerization. In IEC6 cells ZOT induced a peak increment of the PKC-alpha isoform after 3 min incubation. Taken together, these results suggest that ZOT activates a complex intracellular cascade of events that regulate tight junction permeability, probably mimicking the effect of physiologic modulator(s) of epithelial barrier function.
authors.affiliation: Division of Pediatric Gastroenterology and Nutrition, University of Maryland School of Medicine, Baltimore 21201, USA.
authors.forename: A
authors.initials: A
authors.lastname: Fasano
authors.forename: C
authors.initials: C
authors.lastname: Fiorentini
authors.forename: G
authors.initials: G
authors.lastname: Donelli
authors.forename: S
authors.initials: S
authors.lastname: Uzzau
authors.forename: J B
authors.initials: JB
authors.lastname: Kaper
authors.forename: K
authors.initials: K
authors.lastname: Margaretten
authors.forename: X
authors.initials: X
authors.lastname: Ding
authors.forename: S
authors.initials: S
authors.lastname: Guandalini
authors.forename: L
authors.initials: L
authors.lastname: Comstock
authors.forename: S E
authors.initials: SE
authors.lastname: Goldblum
mesh_terms: D000199:Actins / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000494:pharmacology*; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D002277:Carcinoma / Q000473:pathology; D002417:Cattle; D002460:Cell Line; D002772:Cholera Toxin / Q000494:pharmacology*; D003110:Colonic Neoplasms / Q000473:pathology; D003599:Cytoskeleton / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D004730:Endothelium, Vascular / Q000187:drug effects; D004731:Endotoxins; D006801:Humans; D007082:Ileum / Q000187:drug effects; D007365:Intercellular Junctions / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000187:drug effects; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000502:physiology; D007672:Kidney Cortex; D008297:Male; D009928:Organ Specificity; D010539:Permeability / Q000187:drug effects; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010727:Phosphoric Diester Hydrolases / Q000502:physiology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D011651:Pulmonary Artery; D011817:Rabbits; D051381:Rats; D015398:Signal Transduction; D013045:Species Specificity; D019311:Staurosporine / Q000031:analogs & derivatives; D013552:Swine; D014407:Tumor Cells, Cultured; D014734:Vibrio cholerae / Q000502:physiology
chemical_list: D000199:Actins; D000470:Alkaloids; D004731:Endotoxins; D007527:Isoenzymes; C077728:zonula occludens toxin, Vibrio cholerae; D002772:Cholera Toxin; D011493:Protein Kinase C; D010727:Phosphoric Diester Hydrolases; D000251:Adenosine Triphosphatases; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D019311:Staurosporine; C059539:midostaurin