Counter regulatory effects of PKCbetaII and PKCdelta on coronary endothelial permeability.
OBJECTIVE
The aim of this study was to examine the endothelial distribution and activity of selected PKC isoforms in coronary vessels with respect to their functional impact on endothelial permeability under the experimental conditions relevant to diabetes.


RESULTS
En face immunohistochemistry demonstrated a significant increase of PKC(betaII) and decrease of PKCdelta expression in coronary arterial endothelium of Zucker diabetic rats. To test whether changes in PKC expression alter endothelial barrier properties, we measured the transcellular electric resistance in human coronary microvascular endothelial monolayers and found that either PKC(betaII) overexpression or PKCdelta inhibition disrupted the cell-cell adhesive barrier. Three-dimensional fluorescence microscopy revealed that hyperpermeability was caused by altered PKC activity in association with distinct translocation of PKC(betaII) to the cell-cell junction and PKCdelta localization to the cytosol. Further analyses in fractionated endothelial lysates confirmed the differential redistribution of these isozymes. Additionally, FRET analysis of PKC subcellular dynamics demonstrated a high PKC(betaII) activity at the cell surface and junction, whereas PKCdelta activity is concentrated in intracellular membrane organelles.


CONCLUSIONS
Taken together, these data suggest that PKC(betaII) and PKCdelta counter-regulate coronary endothelial barrier properties by targeting distinctive subcellular sites. Imbalanced PKC(betaII)/PKCdelta expression and activity may contribute to endothelial hyperpermeability and coronary dysfunction in diabetes.
Gaudreault
Nathalie
N
Department of Surgery, University of California Davis School of Medicine, 4625 2nd Avenue, Room 3006, Sacramento, CA 95817, USA.
Perrin
Rachel M
RM
Guo
Mingzang
M
Clanton
Chase P
CP
Wu
Mack H
MH
Yuan
Sarah Y
SY
D000818:Animals; D002199:Capillary Permeability / Q000502:physiology*; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000502:physiology*; D003920:Diabetes Mellitus / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology*; D006801:Humans; D008297:Male; D011493:Protein Kinase C / Q000502:physiology*; D064546:Protein Kinase C beta; D051745:Protein Kinase C-delta / Q000502:physiology*; D051381:Rats; D011924:Rats, Zucker
D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051745:Protein Kinase C-delta