Shen, Weiyong; Li, Shiying; Chung, Sook Hyun; Zhu, Ling; Stayt, Jason; Su, Tao; Couraud, Pierre-Olivier; Romero, Ignacio A.; Weksler, Babette and Gillies, Mark C.
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|DOI (Digital Object Identifier) Link:||http://dx.doi.org/10.1016/j.ejcb.2010.10.013|
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Breakdown of the inner blood–retinal barrier and the blood–brain barrier is associated with changes in tight and adherens junction-associated proteins that link vascular endothelial cells. This study aimed to test the hypothesis that transforming growth factor (TGF)-β1 increases the paracellular permeability of vascular endothelial monolayers through tyrosine phosphorylation of VE-cadherin and claudin-5. Bovine retinal and human brain capillary endothelial cells were grown as monolayers on coated polycarbonate membranes. Paracellular permeability was studied by measuring the equilibration of 14C-inulin or fluorescence-labelled dextran. Changes in VE-cadherin and claudin-5 expression were studied by immunocytochemistry (ICC) and quantified by cell-based enzyme linked immunosorbent assays (ELISA). Tyrosine phosphorylation of VE-cadherin and claudin-5 was studied by ICC, immunoprecipitation and Western blotting. We found that exposure of endothelial cells to TGF-β1 caused a dose-dependent increase in paracellular permeability as reflected by increases in the equilibration of 14C-inulin. This effect was enhanced by the tyrosine phosphatase inhibitor orthovanadate and attenuated by the tyrosine kinase inhibitor lavendustin A. ICC and cell-based ELISA revealed that TGF-β1 induced both dose- and time-dependent decreases in VE-cadherin and claudin-5 expression. Assessment of cell viability indicated that changes in these junction-associated proteins were not due to endothelial death or injury. ICC revealed that tyrosine phosphorylation of endothelial monolayers was greatly enhanced by TGF-β1 treatment, and immunoprecipitation of cell lysates showed increased tyrosine phosphorylation of VE-cadherin and claudin-5. Our results suggest that tyrosine phosphorylation of VE-cadherin and claudin-5 is involved in the increased paracellular permeability of central nervous system-derived vascular endothelium induced by TGF-β1.
|Item Type:||Journal Article|
|Copyright Holders:||2010 Elsevier GmbH|
|Keywords:||blood-retinal barrier; blood-brain barrier; transforming growth factor-β1; VE-cadherin; claudin-5; tyrosine phosphorylation|
|Academic Unit/Department:||Science > Life, Health and Chemical Sciences|
|Depositing User:||Astrid Peterkin|
|Date Deposited:||05 Jan 2011 11:40|
|Last Modified:||21 Nov 2012 16:50|
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