Phalloidin enhances endothelial barrier function and reduces inflammatory permeability in vitro.
Phalloidin, a potent microfilament toxin, induces polymerization of actin in vitro and in vivo. In a permeability assay, bovine aortic endothelial cell cultured on microcarrier beads exclude significantly more serum albumin after 30 min treatment with 10(-6), 10(-8), and 10(-10) M phalloidin than controls. Furthermore, pretreatment of microcarriers with 10(-8) M phalloidin significantly reduces permeability increases by histamine, bradykinin, thromboxane A2 mimetic, and cytochalasin B, (all at 10(-6) M). Phalloidin also causes significant surface area and perimeter increases in cultured endothelial cells. The cells also display increased acting stress fibers and show a weblike cytoskeletal pattern of microfilaments. These data suggest that in vitro the endothelial junctional barrier may be enhanced in part by assembly of actin filaments.
Alexander
J S
JS
Boston University, Biological Science Center, Massachusetts 02215.
Hechtman
H B
HB
Shepro
D
D
D000818:Animals; D001012:Aorta, Abdominal; D001920:Bradykinin / Q000494:pharmacology; D002417:Cattle; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002478:Cells, Cultured; D003571:Cytochalasin B / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D006632:Histamine / Q000494:pharmacology; D008863:Microspheres; D009842:Oligopeptides / Q000494:pharmacology*; D010590:Phalloidine / Q000494:pharmacology*; D013928:Thromboxane A2 / Q000494:pharmacology
D009842:Oligopeptides; D010590:Phalloidine; D003571:Cytochalasin B; D013928:Thromboxane A2; D006632:Histamine; D001920:Bradykinin