Transactivation of sphingosine 1-phosphate receptors is essential for vascular barrier regulation. Novel role for hyaluronan and CD44 receptor family.
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.
Singleton
Patrick A
PA
Department of Medicine, Pritzker School of Medicine, University of Chicago, Chicago, Illinois 60637, USA.
Dudek
Steven M
SM
Ma
Shwu-Fan
SF
Garcia
Joe G N
JG
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
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