High-Glucose-Altered Endothelial Cell Function Involves Both Disruption of Cell-to-Cell Connection and Enhancement of Force Development
- Address correspondence to:
Dr. Koji Nobe, Department of Pharmacology, School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-0555, Japan. E-mail: kojinobe{at}pharm.showa-u.ac.jp
Abstract
Vascular endothelial cells (ECs), which regulate vascular tonus, serve as a barrier at the interface of vascular tissue. It is generally believed that alteration of this barrier is correlated with diabetic complications; however, a detailed mechanism has not been elucidated. This study examined alteration of bovine arterial EC functions stimulated by a thromboxane A2 analog (9,11-dideoxy-11α,9α-epoxymethano prostaglandin F2α; U46619) under normal and high-glucose (HG) conditions. U46619 treatment increased EC layer permeability in a time- and dose-dependent fashion. This response initially disrupted calcium-dependent EC-to-EC connections, namely, vascular endothelial cadherin (VE-CaD). Thereafter, EC force development in association with morphological changes was detected employing a reconstituted EC fiber technique, resulting in paracellular hole formation in the EC layer. Thus, we confirmed that U46619-induced enhancement of EC layer permeability involves these sequential steps. Similar trials were performed using a concentration twice that of normal glucose (22.2 mM glucose for 48 h). This treatment significantly enhanced U46619-induced EC layer permeability; furthermore, increases in both rate of VE-CaD disruption and EC fiber contraction were evident. Inhibition of calcium-independent protein kinase C and diacylglycerol kinase indicated that the glucose-dependent increase in VE-CaD disruption was mediated by a calcium-independent mechanism. Moreover, EC contraction was regulated by a typical calcium-independent pathway associated with rho kinase and actin stress fiber. Contraction was also enhanced under HG conditions. This investigation revealed that glucose-dependent enhancement of EC layer permeability is related to increases in VE-CaD disruption and EC contraction. Increases in both parameters were mediated by alteration of a calcium-independent pathway.
Footnotes
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This work was supported to in part by a Showa University grant-in aid for Innovative Collaborative Research Projects and by a Special Research grant-in aid for Development of Characteristic Education from the Japanese Ministry of Education, Culture Sports, Science, and Technology (to K.H.).
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.106.105015.
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ABBREVIATIONS: EC, endothelial cell; PKC, protein kinase C; VE-CaD, vascular endothelial cadherin; HG, high glucose; TXA2, thromboxane A2; U46619, 9,11-dideoxy-11α,9α-epoxymethano prostaglandin F2α; DG, diacylglycerol; PI, phosphatidylinositol; DMEM, Dulbecco's modified Eagle's medium; AM, acetoxymethyl ester; BAPTA, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid; MOPS, 4-morpholinepropanesulfonic acid; PSS, physiological salt solution; BSA, bovine serum albumin; FITC, fluorescein isothiocyanate; ASF, actin stress fiber; Gö-6976, 12-(2-cyanoethyl)-6,7,12,13-tetrahydro-13-methyl-5-oxo-5H-indolo(2,3-a)pyrrolo(3,4-c)-carbazole; U73122, 1-[6-[[17β-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione; SQ29548, [1S-[1α,2α(Z),3α,4α]]-7-[3[[2-[(phenylamino)carbonyl[hydrazino]methyl]-7-oxabicyclo]2.2.1]hept-2-yl]-5-heptenoic acid; R59022, 6-{2-{4-[(4-fluorophenyl)phenylmethylene]-1-piperidinyl}ethyl}-7-methyl-5H-thiazolo(3,2-α)pyrimidine-5-one; Y27632, ((+)-(R)-trans-4-(1-aminoethyl)-N-(4-pyridyl) cyclohexane carboxamide dihydrochloride, monohydrate.
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- Received March 21, 2006.
- Accepted May 11, 2006.
- The American Society for Pharmacology and Experimental Therapeutics
