title: Transactivation of sphingosine 1-phosphate receptors is essential for vascular barrier regulation. Novel role for hyaluronan and CD44 receptor family.
abstract: 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.
authors.affiliation: Department of Medicine, Pritzker School of Medicine, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Singleton
authors.forename: Steven M
authors.initials: SM
authors.lastname: Dudek
authors.forename: Shwu-Fan
authors.initials: SF
authors.lastname: Ma
authors.forename: Joe G N
authors.initials: JG
authors.lastname: Garcia
mesh_terms: D000199:Actins / Q000378:metabolism; D001808:Blood Vessels / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation; D002478:Cells, Cultured; D003599:Cytoskeleton; D017097:Electric Impedance; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000473:pathology; D005455:Fluorescent Antibody Technique; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism*; D015151:Immunoblotting; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008055:Lipids; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011651:Pulmonary Artery / Q000166:cytology / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D049349:Receptors, Lysosphingolipid / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D015533:Transcriptional Activation; D020830:rac1 GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D018960:Hyaluronan Receptors; D047908:Intracellular Signaling Peptides and Proteins; D008055:Lipids; D034741:RNA, Small Interfering; D049349:Receptors, Lysosphingolipid; D006820:Hyaluronic Acid; D016392:Proto-Oncogene Proteins pp60(c-src); D017346:Protein Serine-Threonine Kinases; C515851:ROCK1 protein, human; D054460:rho-Associated Kinases; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein