1. Zonula occludens toxin modulates tight junctions through protein kinase C-dependent actin reorganization, in vitro.
- Author
-
Fasano A, Fiorentini C, Donelli G, Uzzau S, Kaper JB, Margaretten K, Ding X, Guandalini S, Comstock L, and Goldblum SE
- Subjects
- Alkaloids pharmacology, Animals, Carcinoma pathology, Cattle, Cell Line, Colonic Neoplasms pathology, Cytoskeleton metabolism, Cytoskeleton ultrastructure, Endothelium, Vascular drug effects, Endotoxins, Humans, Ileum drug effects, Intestinal Mucosa drug effects, Isoenzymes antagonists & inhibitors, Isoenzymes physiology, Kidney Cortex, Male, Organ Specificity, Permeability drug effects, Phosphatidylinositol Diacylglycerol-Lyase, Phosphoric Diester Hydrolases physiology, Protein Kinase C antagonists & inhibitors, Pulmonary Artery, Rabbits, Rats, Species Specificity, Staurosporine, Swine, Tumor Cells, Cultured, Vibrio cholerae physiology, Actins metabolism, Adenosine Triphosphatases pharmacology, Cholera Toxin pharmacology, Cytoskeleton drug effects, Intercellular Junctions drug effects, Protein Kinase C physiology, Signal Transduction
- 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.
- Published
- 1995
- Full Text
- View/download PDF