title: Anthrax lethal toxin induces endothelial barrier dysfunction.
abstract: Hemorrhage and pleural effusion are prominent pathological features of systemic anthrax infection. We examined the effect of anthrax lethal toxin (LT), a major virulence factor of Bacillus anthracis, on the barrier function of primary human lung microvascular endothelial cells. We also examined the distribution patterns of cytoskeletal actin and vascular endothelial-cadherin (VE-cadherin), both of which are involved in barrier function regulation. Endothelial monolayers cultured on porous membrane inserts were treated with the LT components lethal factor (LF) and protective antigen (PA) individually, or in combination. LT induced a concentration- and time-dependent decrease in transendothelial electrical resistance that correlated with increased permeability to fluorescently labeled albumin. LT also produced a marked increase in central actin stress fibers and significantly altered VE-cadherin distribution as revealed by immunofluorescence microscopy and cell surface enzyme-linked immunosorbent assay. Treatment with LF, PA, or the combination of an inactive LF mutant and PA did not alter barrier function or the distribution of actin or VE-cadherin. LT-induced barrier dysfunction was not dependent on endothelial apoptosis or necrosis. The present findings support a possible role for LT-induced barrier dysfunction in the vascular permeability changes accompanying systemic anthrax infection.
authors.affiliation: Laboratory of Biochemistry and Vascular Biology, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, 29 Lincoln Drive, Bldg. 29, Rm. 129, Bethesda, MD 20892, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Warfel
authors.forename: Amber D
authors.initials: AD
authors.lastname: Steele
authors.forename: Felice
authors.initials: F
authors.lastname: D'Agnillo
mesh_terms: D000942:Antigens, Bacterial / Q000633:toxicity*; D001427:Bacterial Toxins / Q000633:toxicity*; D015820:Cadherins / Q000187:drug effects / Q000378:metabolism; D002199:Capillary Permeability / Q000187:drug effects*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D017097:Electric Impedance; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008856:Microscopy, Fluorescence
chemical_list: D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D015820:Cadherins; C502403:FAT1 protein, human; C030325:anthrax toxin