title: Association between adherens junctions and tight junctions via Rap1 promotes barrier protective effects of oxidized phospholipids.
abstract: Previous studies showed that cyclopenthenone-containing products resulting from oxidation of a natural phospholipid, 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (OxPAPC) exhibit potent barrier-protective effects in the in vitro and in vivo models of lung endothelial cell (EC) barrier dysfunction, and these effects are associated with enhancement of peripheral actin cytoskeleton, cell-cell and cell-substrate contacts driven by activation of Rac and Cdc42 GTPases. Rap1 GTPase is another member of small GTPase family involved in control of cell-cell interactions; however, its involvement in EC barrier-protective effects by OxPAPC remains unknown. This study examined a role of Rap1 in regulation of OxPAPC-induced interactions in adherens junctions (AJ) and tight junctions (TJ) as a novel mechanism of EC barrier preservation in vitro and in vivo. Immunofluorescence analysis, subcellular fractionation, and co-immunoprecipitation assays indicate that OxPAPC promoted accumulation of AJ proteins: VE-cadherin, p120-catenin, and β-catenin; and TJ proteins: ZO-1, occludin, and JAM-A in the cell membrane, and induced novel cross-interactions between AJ and TJ protein complexes, that were dependent on OxPAPC-induced Rap1 activation. Inhibition of Rap1 function suppressed OxPAPC-mediated pulmonary EC barrier enhancement and AJ and TJ interactions in vitro, as well as inhibited protective effects of OxPAPC against ventilator-induced lung injury in vivo. These results show for the first time a role of Rap1-mediated association between adherens junctions and tight junction complexes in the OxPAPC-induced pulmonary vascular EC barrier protection.
authors.affiliation: Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA. kbirukov@medicine.bsd.uchicago.edu
authors.forename: Anna A
authors.initials: AA
authors.lastname: Birukova
authors.forename: Noureddine
authors.initials: N
authors.lastname: Zebda
authors.forename: Panfeng
authors.initials: P
authors.lastname: Fu
authors.forename: Valery
authors.initials: V
authors.lastname: Poroyko
authors.forename: Ivan
authors.initials: I
authors.lastname: Cokic
authors.forename: Konstantin G
authors.initials: KG
authors.lastname: Birukov
mesh_terms: D022005:Adherens Junctions / Q000378:metabolism*; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D051177:Catenins / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002460:Cell Line; D042783:Endothelial Cells / Q000378:metabolism; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism*; D008168:Lung / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D062793:Occludin; D010713:Phosphatidylcholines / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011651:Pulmonary Artery / Q000378:metabolism; D011956:Receptors, Cell Surface; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins / Q000378:metabolism*; D019108:Tight Junctions / Q000378:metabolism*; D055397:Ventilator-Induced Lung Injury / Q000378:metabolism; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin / Q000378:metabolism; D000095002:Delta Catenin; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D015820:Cadherins; D051177:Catenins; D015815:Cell Adhesion Molecules; D007136:Immunoglobulins; D008565:Membrane Proteins; D062793:Occludin; D010713:Phosphatidylcholines; D010750:Phosphoproteins; D011956:Receptors, Cell Surface; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin; D000095002:Delta Catenin; D000099152:Cadherin 5; C407243:F11R protein, human; C568985:OCLN protein, human; C568986:Ocln protein, mouse; C440809:TERF2IP protein, human; C569042:TJP1 protein, human; C569043:Tjp1 protein, mouse; C472349:oxidized-L-alpha-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine