title: Signaling pathways involved in OxPAPC-induced pulmonary endothelial barrier protection.
abstract: Increased tissue or serum levels of oxidized phospholipids have been detected in a variety of chronic and acute pathological conditions such as hyperlipidemia, atherosclerosis, heart attack, cell apoptosis, acute inflammation and injury. We have recently described signaling cascades activated by oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (OxPAPC)in the human pulmonary artery endothelial cells (EC) and reported potent barrier-protective effects of OxPAPC, which were mediated by small GTPases Rac and Cdc42. In this study we have further characterized signal transduction pathways involved in the OxPAPC-mediated endothelial barrier protection. Inhibitors of small GTPases, protein kinase A (PKA), protein kinase C (PKC), Src family kinases and general inhibitors of tyrosine kinases attenuated OxPAPC-induced barrier-protective response and EC cytoskeletal remodeling. In contrast, small GTPase Rho, Rho kinase, Erk-1,2 MAP kinase and p38 MAP kinase and PI3-kinase were not involved in the barrier-protective effects of OxPAPC. Inhibitors of PKA, PKC, tyrosine kinases and small GTPase inhibitor toxin B suppressed OxPAPC-induced Rac activation and decreased phosphorylation of focal adhesion kinase (FAK) and paxillin. Barrier-protective effects of OxPAPC were not reproduced by platelet activating factor (PAF), which at high concentrations induced barrier dysfunction, but were partially attenuated by PAF receptor antagonist A85783. These results demonstrate for the first time upstream signaling cascades involved in the OxPAPC-induced Rac activation, cytoskeletal remodeling and barrier regulation and suggest PAF receptor-independent mechanisms of OxPAPC-mediated endothelial barrier protection.
authors.affiliation: Section of Pulmonary and Critical Medicine, Department of Medicine, Division of Biomedical Sciences, University of Chicago, 929 East 57th Street, CIS Bldg., W410, Chicago, IL 60637, USA.
authors.forename: Anna A
authors.initials: AA
authors.lastname: Birukova
authors.forename: Santipongse
authors.initials: S
authors.lastname: Chatchavalvanich
authors.forename: Olga
authors.initials: O
authors.lastname: Oskolkova
authors.forename: Valery N
authors.initials: VN
authors.lastname: Bochkov
authors.forename: Konstantin G
authors.initials: KG
authors.lastname: Birukov
mesh_terms: D000199:Actins / Q000378:metabolism; D001426:Bacterial Proteins / Q000494:pharmacology; D001427:Bacterial Toxins / Q000494:pharmacology; D002199:Capillary Permeability / Q000187:drug effects; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D017097:Electric Impedance; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D006801:Humans; D051419:Paxillin / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism* / Q000494:pharmacology; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D022502:Stress Fibers / Q000378:metabolism; D020744:rac GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000199:Actins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; C496061:PXN protein, human; D051419:Paxillin; D010713:Phosphatidylcholines; D047428:Protein Kinase Inhibitors; C472349:oxidized-L-alpha-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine; C031815:toxB protein, Clostridium difficile; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human; D019061:src-Family Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D020744:rac GTP-Binding Proteins