Mildly oxidized low density lipoprotein induces contraction of human endothelial cells through activation of Rho/Rho kinase and inhibition of myosin light chain phosphatase.
Mildly oxidized low density lipoprotein (mox-LDL) is critically involved in the early atherogenic responses of the endothelium and increases endothelial permeability through an unknown signal pathway. Here we show that (i) exposure of confluent human endothelial cells (HUVEC) to mox-LDL but not to native LDL induces the formation of actin stress fibers and intercellular gaps within minutes, leading to an increase in endothelial permeability; (ii) mox-LDL induces a transient decrease in myosin light chain (MLC) phosphatase that is paralleled by an increase in MLC phosphorylation; (iii) phosphorylated MLC stimulated by mox-LDL is incorporated into stress fibers; (iv) cytoskeletal rearrangements and MLC phosphorylation are inhibited by C3 transferase from Clostridium botulinum, a specific Rho inhibitor, and Y-27632, an inhibitor of Rho kinase; and (v) mox-LDL does not increase intracellular Ca(2+) concentration. Our data indicate that mox-LDL induces endothelial cell contraction through activation of Rho and its effector Rho kinase which inhibits MLC phosphatase and phosphorylates MLC. We suggest that inhibition of this novel cell signaling pathway of mox-LDL could be relevant for the prevention of atherosclerosis.
Essler
M
M
Institut für Prophylaxe und Epidemiologie der Kreislaufkrankheiten, Universität München, Pettenkoferstrasse 9, 80336 München, Germany. messler@klp.med.unimuenchen.de
Retzer
M
M
Bauer
M
M
Heemskerk
J W
JW
Aepfelbacher
M
M
Siess
W
W
D036002:ADP Ribose Transferases / Q000494:pharmacology; D000577:Amides / Q000494:pharmacology; D001905:Botulinum Toxins; D002478:Cells, Cultured; D003014:Clostridium botulinum; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006706:Homeostasis; D006735:Horseradish Peroxidase / Q000493:pharmacokinetics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D018994:Myosin Light Chains / Q000378:metabolism; D043263:Myosin-Light-Chain Phosphatase; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D014471:Umbilical Veins; D020741:rho GTP-Binding Proteins / Q000378:metabolism*; D054460:rho-Associated Kinases
D000577:Amides; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D008077:Lipoproteins, LDL; D018994:Myosin Light Chains; D011725:Pyridines; C099252:oxidized low density lipoprotein; C108830:Y 27632; D006735:Horseradish Peroxidase; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D010749:Phosphoprotein Phosphatases; D043263:Myosin-Light-Chain Phosphatase; D001905:Botulinum Toxins; D020741:rho GTP-Binding Proteins