p38 MAPK activation by TGF-beta1 increases MLC phosphorylation and endothelial monolayer permeability.
Transforming growth factor (TGF)-beta1 increases endothelial monolayer permeability and myosin light chain phosphorylation (MLC-P) beginning 1-2 h posttreatment, suggesting that changes in gene expression may be required for these responses. The role of extracellular signal-regulated kinase (ERK) 1/2 and p38 mitogen-activated protein kinase (p38 MAPK) was investigated because both kinases have been implicated in regulating gene expression after TGF-beta1. ERK1/2 phosphorylation increased threefold above the control level, and the increase was temporally associated with the increase in MLC-P. Inhibition of ERK1/2 phosphorylation with the MAPK kinase inhibitor U-0126 did not prevent the increase in either monolayer permeability or MLC-P. p38 MAPK phosphorylation increased fourfold above the control level, but unlike ERK1/2, this increase peaked 30 min and 1 h post-TGF-beta1 treatment. Inhibition of p38 MAPK activity with SB-203580 prevented the increases in both monolayer permeability and MLC-P. Treatment of the monolayers with cycloheximide in conjunction with TGF-beta1-inhibited MLC-P, showing a requirement for protein synthesis. These studies demonstrate that p38 MAPK activation and subsequent protein synthesis are part of the signal transduction pathway leading to the TGF-beta1-induced increases in monolayer permeability and MLC-P.
Goldberg
Peter L
PL
Center for Cardiovascular Sciences, Albany Medical College, Albany, New York 12208, USA.
MacNaughton
Darren E
DE
Clements
Richard T
RT
Minnear
Fred L
FL
Vincent
Peter A
PA
D000818:Animals; D002199:Capillary Permeability / Q000187:drug effects*; D002417:Cattle; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D004789:Enzyme Activation; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D018994:Myosin Light Chains / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D014176:Protein Biosynthesis; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1; D048051:p38 Mitogen-Activated Protein Kinases
D018994:Myosin Light Chains; D011500:Protein Synthesis Inhibitors; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D003513:Cycloheximide; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases