Rearrangement of adherens junctions by transforming growth factor-beta1: role of contraction.
The signal transduction pathways that lead to disruption of pulmonary endothelial monolayer integrity by transforming growth factor-beta1 (TGF-beta1) have not been elucidated. The purpose of this investigation was to determine whether disassembly of the adherens junction is temporally associated with the TGF-beta1-induced decrease in pulmonary endothelial monolayer integrity. Measurement of albumin clearance and electrical resistance showed that monolayer integrity started to decrease between 1 and 2 h post-TGF-beta1 treatment and continued to slowly decrease over the next 6 h. Immunofluorescence microscopy of monolayers between 2 and 3 h post-TGF-beta1 showed that beta-catenin, plakoglobin, alpha-catenin, and cadherin-5 were colocalized both at the cell periphery and in newly formed bands that are perpendicular to the cell-cell border. At 4 h post-TGF-beta1, cells began separating; however, beta- and alpha-catenin, plakoglobin, and cadherin-5 could still be found at the cell periphery at areas of cell separation and in strands between separated cells. By 8 h, these junctional proteins were no longer present at the cell periphery at areas of cell separation. The myosin light chain kinase inhibitor KT-5926 prevented the TGF-beta1-induced change in integrity but did not inhibit the formation of actin stress fibers or the formation of bands containing adherens junction proteins that were perpendicular to the cell-cell junction. Overall, these results suggest that adherens junction disassembly occurs after cell separation during TGF-beta1-induced decreases in pulmonary endothelial monolayer integrity and that the loss of integrity may be due to the activation of a myosin light chain kinase-dependent signaling cascade.
Hurst V
I V
IV
Department of Physiology and Cell Biology, Albany Medical College, Albany, New York 12208, USA.
Goldberg
P L
PL
Minnear
F L
FL
Heimark
R L
RL
Vincent
P A
PA
D000818:Animals; D015703:Antigens, CD; D015820:Cadherins / Q000032:analysis; D002417:Cattle; D002448:Cell Adhesion; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000032:analysis; D051180:Desmoplakins; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D007365:Intercellular Junctions / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D007700:Kinetics; D008564:Membrane Potentials / Q000502:physiology; D011651:Pulmonary Artery; D013997:Time Factors; D015534:Trans-Activators; D016212:Transforming Growth Factor beta / Q000494:pharmacology* / Q000502:physiology; D051178:alpha Catenin; D051176:beta Catenin; D051185:gamma Catenin; D000099152:Cadherin 5
D015703:Antigens, CD; D015820:Cadherins; D003598:Cytoskeletal Proteins; D051180:Desmoplakins; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D051178:alpha Catenin; D051176:beta Catenin; D051185:gamma Catenin; D000099152:Cadherin 5