Rearrangement of adherens junctions by transforming growth factor-β1: role of contraction

Abstract

The signal transduction pathways that lead to disruption of pulmonary endothelial monolayer integrity by transforming growth factor-β1 (TGF-β1) have not been elucidated. The purpose of this investigation was to determine whether disassembly of the adherens junction is temporally associated with the TGF-β1-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-β1 treatment and continued to slowly decrease over the next 6 h. Immunofluorescence microscopy of monolayers between 2 and 3 h post-TGF-β1 showed that β-catenin, plakoglobin, α-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-β1, cells began separating; however, β- and α-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-β1-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-β1-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.

TGF-β1 induces transendothelial migration of the pathogenic fungus Sporothrix schenckii by a paracellular route involving extracellular matrix proteins

“…Indeed, the treatment of HUVECs with TGF-b1 resulted in significant exposure of the subendothelial matrix. This result is corroborated by the work of others, who demonstrated that TGF-b1 promotes a strong rearrangement of endothelial adherent junctions and actin cytoskeleton, resulting in increased areas of cell separation (Goldblum et al, 1999;Hurst et treated or not with 10 ng TGF-b1 ml "1 for 4 h, were pre-incubated with polyclonal anti-FN antibodies or rabbit control IgGs (both at 10 mg ml "1 ), or with an anti-LM serum or a pre-immune serum (both at 1 : 1000). Then cultures were incubated with S. schenckii yeasts (5¾10 6 cells) for 90 min.…”

“…It has been suggested that actin cortical patches may be essential for the initiation of endocytosis (EngqvistGoldstein & Drubin, 2003). Interestingly, treatment of HUVECs with TGF-b1 induced a modification in the microfilament cytoskeleton structure, leading to an actin rearrangement from a cortical pattern to an array of perpendicular stress fibres, as already described by others (Goldblum et al, 1999;Hurst et al, 1999).…”

“…Some reports have implicated TGF-b1 in the induction of changes in endothelial cell phenotype, including loss of cell-cell contact, rearrangement in endothelial cell actin cytoskeleton and impairment of endothelial permeability (Coomber, 1991;Molony & Armstrong, 1991;Hurst et al, 1999;Goldberg et al, 2002). In this study, a fluorescence microscopy approach was used to analyse changes in actin distribution in HUVECs treated with TGF-b1 for 4 h. Although the presence of stress fibre-bearing cells was observed under all conditions, the quantification of at least five high-power fields showed that TGF-b1 treatment increased the number of endothelial cells exhibiting abundant stress fibre cells (37.5±4.3 % in treated cultures compared to the 12.45±2.4 % observed in untreated cells; Fig.…”

Transforming Growth Factor β1 Inhibits Cystic Fibrosis Transmembrane Conductance Regulator-dependent cAMP-stimulated Alveolar Epithelial Fluid Transport via a Phosphatidylinositol 3-Kinase-dependent Mechanism

“…First, the concentration of TGF-␤1 is elevated in edema fluid from patients with acute lung injury (18), and active TGF-␤1 is present early in the syndrome, detectable within 24 h of initial diagnosis (19). TGF-␤1 has been associated with increased endothelial and epithelial permeability, leading to pulmonary edema (20,21). We have also shown that increased TGF-␤1 activity in the distal airspaces during ALI promotes alveolar edema by reducing distal airspace epi-thelial sodium and fluid clearance.…”

Effect of Shear Stress on Permeability of Vascular Endothelial Monolayer Cocultured with Smooth Muscle Cells

“…It was reported that rearrangement of expression of VE-cadherin, the transmembrane protein for the formation of adherens junction, occurred under shear conditions (14) . Furthermore, tumor necrosis factor-α (TNF-α) (15) and TGF-ß1 (16) , which are synthesized by SMCs, have effects on expression of VEcadherin. For quantitative analysis of EC permeability, well-defined flow conditions and cellular interactions between ECs and SMCs are necessary.…”