Effects of cytotoxic necrotizing factor 1 and lethal toxin on actin cytoskeleton and VE-cadherin localization in human endothelial cell monolayers.
Integrity of the vascular endothelium is largely dependent on endothelial cell shape and establishment of intercellular junctions. Certain pathogenic bacterial toxins alter the cytoskeletal architecture of intoxicated cells by modulating the GTPase activity of p21 Rho family proteins. In the present study we have analyzed the effect of Rho-directed toxins on the actin cytoskeleton and monolayer integrity of endothelial cells. We report here that Escherichia coli cytotoxic necrotizing factor 1 (CNF1) activates Rho in human umbilical vein endothelial cells (HUVEC). In confluent monolayers, CNF1 treatment induces prominent stress fiber formation without significantly modifying peripheral localization of VE-cadherin, a specific marker of vascular endothelial cell adherens junctions. Further, Rho activation with CNF1 blocks thrombin-induced redistribution of VE-cadherin staining and gap formation in HUVEC monolayers. Inhibition of Rho by prolonged treatment of cells with C3 exoenzyme (Clostridium botulinum) eliminates actin stress fibers without disrupting the continuity of VE-cadherin staining, indicating that Rho-dependent stress fibers are not required for maintaining this adhesion receptor at sites of intercellular contact. Lethal toxin (Clostridium sordellii), an inhibitor of Rac as well as Ras and Rap, potently disrupts the actin microfilament system and monolayer integrity in HUVEC cultures.
Vouret-Craviari
V
V
Centre de Biochimie, CNRS UMR 6543, 06108 Nice Cedex 2, France.
Grall
D
D
Flatau
G
G
Pouysségur
J
J
Boquet
P
P
Van Obberghen-Schilling
E
E
D036002:ADP Ribose Transferases / Q000378:metabolism / Q000494:pharmacology; D000199:Actins / Q000187:drug effects / Q000378:metabolism*; D015703:Antigens, CD; D001427:Bacterial Toxins / Q000378:metabolism* / Q000494:pharmacology; D001905:Botulinum Toxins; D015820:Cadherins / Q000032:analysis*; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000187:drug effects; D003603:Cytotoxins / Q000378:metabolism* / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D029968:Escherichia coli Proteins; D020558:GTP Phosphohydrolases / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D020741:rho GTP-Binding Proteins; D000099152:Cadherin 5
D036002:ADP Ribose Transferases; D000199:Actins; D015703:Antigens, CD; D001427:Bacterial Toxins; D001905:Botulinum Toxins; D015820:Cadherins; D003603:Cytotoxins; D029968:Escherichia coli Proteins; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D020741:rho GTP-Binding Proteins; D000099152:Cadherin 5; C072292:lethal toxin LT, Clostridium sordellii; C060296:cytotoxic necrotizing factor type 1; C063007:exoenzyme C3, Clostridium botulinum