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.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Actins / metabolism
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Blood Vessels / metabolism*
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Blood Vessels / pathology
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Cell Differentiation
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Cells, Cultured
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Cytoskeleton
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Electric Impedance
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Endothelium, Vascular / metabolism*
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Endothelium, Vascular / pathology
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Fluorescent Antibody Technique
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Humans
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Hyaluronan Receptors / metabolism*
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Hyaluronic Acid / metabolism*
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Immunoblotting
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Immunoprecipitation
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Intracellular Signaling Peptides and Proteins / antagonists & inhibitors
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Intracellular Signaling Peptides and Proteins / genetics
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Intracellular Signaling Peptides and Proteins / metabolism
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Lipids
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Phosphorylation
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Protein Serine-Threonine Kinases / antagonists & inhibitors
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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Proto-Oncogene Proteins pp60(c-src) / antagonists & inhibitors
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Proto-Oncogene Proteins pp60(c-src) / genetics
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Proto-Oncogene Proteins pp60(c-src) / metabolism
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Pulmonary Artery / cytology
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Pulmonary Artery / metabolism
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RNA, Small Interfering / pharmacology
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Receptors, Lysosphingolipid / antagonists & inhibitors
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Receptors, Lysosphingolipid / genetics
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Receptors, Lysosphingolipid / metabolism*
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Signal Transduction
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Transcriptional Activation*
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rac1 GTP-Binding Protein / antagonists & inhibitors
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rac1 GTP-Binding Protein / genetics
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rac1 GTP-Binding Protein / metabolism
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rho-Associated Kinases
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rhoA GTP-Binding Protein / antagonists & inhibitors
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rhoA GTP-Binding Protein / genetics
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rhoA GTP-Binding Protein / metabolism
Substances
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Actins
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Hyaluronan Receptors
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Intracellular Signaling Peptides and Proteins
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Lipids
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RNA, Small Interfering
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Receptors, Lysosphingolipid
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Hyaluronic Acid
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Proto-Oncogene Proteins pp60(c-src)
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Protein Serine-Threonine Kinases
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ROCK1 protein, human
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rho-Associated Kinases
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rac1 GTP-Binding Protein
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rhoA GTP-Binding Protein