Transactivation of sphingosine 1-phosphate receptors is essential for vascular barrier regulation. Novel role for hyaluronan and CD44 receptor family.

TitleTransactivation of sphingosine 1-phosphate receptors is essential for vascular barrier regulation. Novel role for hyaluronan and CD44 receptor family.
Publication TypeJournal Article
Year of Publication2006
AuthorsSingleton PA, Dudek SM, Ma S-F, Garcia JGN
JournalJ Biol Chem
Volume281
Issue45
Pagination34381-93
Date Published2006 Nov 10
ISSN Number0021-9258
KeywordsActins, Blood Vessels, Cell Differentiation, Cells, Cultured, Cytoskeleton, Electric Impedance, Endothelium, Vascular, Fluorescent Antibody Technique, Humans, Hyaluronan Receptors, Hyaluronic Acid, Immunoblotting, Immunoprecipitation, Intracellular Signaling Peptides and Proteins, Lipids, Phosphorylation, Protein-Serine-Threonine Kinases, Proto-Oncogene Proteins pp60(c-src), Pulmonary Artery, rac1 GTP-Binding Protein, Receptors, Lysosphingolipid, rho-Associated Kinases, rhoA GTP-Binding Protein, RNA, Small Interfering, Signal Transduction, Transcriptional Activation
Abstract

<p>The role for hyaluronan (HA) and CD44 in vascular barrier regulation is unknown. We examined high and low molecular weight HA (HMW-HA, approximately 1,000 kDa; LMW-HA, approximately 2.5 kDa) effects on human transendothelial monolayer electrical resistance (TER). HMW-HA increased TER, whereas LMW-HA induced biphasic TER changes ultimately resulting in EC barrier disruption. HMW-HA induced the association of the CD44s isoform with, and AKT-mediated phosphorylation of, the barrier-promoting sphingosine 1-phosphate receptor (S1P1) within caveolin-enriched lipid raft microdomains, whereas LMW-HA induced brief CD44s association with S1P1 followed by sustained association of the CD44v10 isoform with, and Src and ROCK 1/2-mediated phosphorylation of, the barrier-disrupting S1P3 receptor. HA-induced EC cytoskeletal reorganization and TER alterations were abolished by either disruption of lipid raft formation, CD44 blocking antibody or siRNA-mediated reductions in expression of CD44 isoforms. Silencing S1P1, AKT1, or Rac1 blocked the barrier enhancing effects of HA whereas silencing S1P3, Src, ROCK1/2, or RhoA blocked the barrier disruption induced by LMW-HA. In summary, HA regulates EC barrier function through novel differential CD44 isoform interaction with S1P receptors, S1P receptor transactivation, and RhoA/Rac1 signaling to the EC cytoskeleton.</p>

DOI10.1074/jbc.M603680200
Alternate JournalJ. Biol. Chem.
PubMed ID16963454
Grant ListF32 HL68472 / HL / NHLBI NIH HHS / United States