Junctional complex and focal adhesion rearrangement mediates pulmonary endothelial barrier enhancement by FTY720 S-phosphonate.

TitleJunctional complex and focal adhesion rearrangement mediates pulmonary endothelial barrier enhancement by FTY720 S-phosphonate.
Publication TypeJournal Article
Year of Publication2015
AuthorsWang L, Bittman R, Garcia JGN, Dudek SM
JournalMicrovasc Res
Volume99
Pagination102-9
Date Published2015 May
ISSN Number1095-9319
KeywordsAcute Lung Injury, Antigens, CD, Antigens, Nuclear, Cadherins, Endothelial Cells, Fingolimod Hydrochloride, Focal Adhesion Protein-Tyrosine Kinases, Focal Adhesions, Humans, Immunosuppressive Agents, Lung, Lysophospholipids, Microscopy, Fluorescence, Nerve Tissue Proteins, Organophosphonates, Proto-Oncogene Proteins c-akt, rac1 GTP-Binding Protein, Receptors, Lysosphingolipid, RNA, Small Interfering, Sphingosine, Transcription Factors, Zonula Occludens-1 Protein
Abstract

<p><b>RATIONALE: </b>Modulation of pulmonary vascular barrier function is an important clinical goal given the devastating effects of vascular leak in acute lung injury (ALI). We previously demonstrated that FTY720 S-phosphonate (Tys), an analog of sphingosine 1-phosphate (S1P) and FTY720, has more potent pulmonary barrier protective effects than these agents in vitro and in mouse models of ALI. Tys preserves expression of the barrier-promoting S1P1 receptor (S1PR1), whereas S1P and FTY720 induce its ubiquitination and degradation. Here we further characterize the novel barrier promoting effects of Tys in cultured human pulmonary endothelial cells (EC).</p><p><b>METHODS/RESULTS: </b>In human lung EC, Tys significantly increased peripheral redistribution of adherens junction proteins VE-cadherin and β-catenin and tight junction protein ZO-1. Inhibition of VE-cadherin with blocking antibody significantly attenuated Tys-induced transendothelial resistance (TER) elevation, while ZO-1 siRNA partially inhibited this elevation. Tys significantly increased focal adhesion formation and phosphorylation of focal adhesion kinase (FAK). Pharmacologic inhibition of FAK significantly attenuated Tys-induced TER elevation. Tys significantly increased phosphorylation and peripheral redistribution of the actin-binding protein, cortactin, while cortactin siRNA partially attenuated Tys-induced TER elevation. Although Tys significantly increased phosphorylation of Akt and GSK3β, neither PI3 kinase nor GSK3β inhibition altered Tys-induced TER elevation. Tys significantly increased Rac1 activity, while inhibition of Rac1 activity significantly attenuated Tys-induced VE-cadherin redistribution and TER elevation.</p><p><b>CONCLUSION: </b>Junctional complex, focal adhesion rearrangement and Rac1 activation play critical roles in Tys-mediated barrier protection in pulmonary EC. These results provide mechanistic insights into the effects of this potential ALI therapy.</p>

DOI10.1016/j.mvr.2015.03.007
Alternate JournalMicrovasc. Res.
PubMed ID25862132
PubMed Central IDPMC5032626
Grant ListR01 HL 88144 / HL / NHLBI NIH HHS / United States
P01 HL 58064 / HL / NHLBI NIH HHS / United States
P01 HL 98050 / HL / NHLBI NIH HHS / United States
P01 HL098050 / HL / NHLBI NIH HHS / United States
R01 HL088144 / HL / NHLBI NIH HHS / United States
P01 HL058064 / HL / NHLBI NIH HHS / United States