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Novel Rap1‐dependent regulator of endothelial cell junctions afadin mediates protective effects by oxidized phospholipids in the models of acute lung injury
Author(s) -
Birukov Konstantin G,
Sarich Nicolene,
Dubrovskyi Oleksii,
Zebda Noureddine
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1131.4
Subject(s) - adherens junction , rap1 , microbiology and biotechnology , tight junction , rhoa , chemistry , endothelial stem cell , gtpase , gene knockdown , biology , cell , cadherin , signal transduction , in vitro , biochemistry , apoptosis
Afadin has been described as a regulator of epithelial cell junctions assembly. However, its role in control of vascular permeability remains obscure. We have previously described protective effects of oxidized phospohlipids (OxPL). This study examined a role of afadin and its upstream regulator Rap1 GTPase in the OxPL‐induced cell junction assembly as a novel mechanism of endothelial cell barrier preservation. OxPL induced Rap1‐ dependent afadin translocation to the cell periphery and promoted accumulation of adherens junction and tight junction proteins at the cell membrane. OxPL also stimulated Rap1‐dependent afadin interactions with adherens junction and tight junction proteins p120‐catenin and ZO‐1, respectively. SiRNA‐induced knockdown of afadin or Rap1 suppressed endothelial barrier enhancement caused by OxPL and abolished barrier protective effects of OxPL against thrombin‐induced endothelial permeability. Similar effects were obtained in experiments with ectopic expression of afadin mutant lacking Rap1 GTPase binding domain or inhibitor of Rap1 activity, Rap1‐GAP. Afadin or Rap1 siRNA‐mediated knockdown also abolished protective effects of OxPL against acute lung injury in vivo. These results demonstrate for the first time a critical role of afadin in the regulation of vascular barrier function in vitro and in vivo. Funding: NHLBI HL76259, HL089257 , HL107920