Zonula occludens toxin modulates tight junctions through protein kinase C-dependent actin reorganization, in vitro.
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.
Fasano
A
A
Division of Pediatric Gastroenterology and Nutrition, University of Maryland School of Medicine, Baltimore 21201, USA.
Fiorentini
C
C
Donelli
G
G
Uzzau
S
S
Kaper
J B
JB
Margaretten
K
K
Ding
X
X
Guandalini
S
S
Comstock
L
L
Goldblum
S E
SE
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
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