A role for PKCβ in altering calcium homeostasis under hyperglycemic conditions in human endothelial cells

Document Type

Abstract

Publication Title

FASEB Journal

ISSN

0892-6638

Volume

26

Issue

Supp 1

DOI

10.1096/fasebj.26.1_supplement.840.10

Publication Date

1-1-2012

Abstract

Cardiovascular diseases (CVD) are leading causes of morbidity and mortality for diabetic patients. Endothelial cell dysfunction is a hallmark of CVD. Intracellular Ca2+ concentration ([Ca2+]i) may regulate endothelial cell function. Here, we investigated the effects of hyperglycemia on [Ca2+]i and a role for protein kinase C (PKC) in regulating [Ca2+]i in the human endothelial cell line, EA.hy926. Cells were cultured in normal (5.5 mM, NG) or high (25 mM, HG) glucose media then treated with either a) vehicle (0.1% DMSO), b) LY341684 (selective PKC? inhibitor, 100 nM, 24h), or c) phorbol 12-myristate 13-acetate (PMA, PKC activator, 200 nM, 4h). Using a spectrofluorometer, [Ca2+]i in cells loaded with Fura 2-AM was monitored in the absence of extracellular Ca2+. Thapsigargin (SERCA inhibitor, 1 ?M,) induced a transient increase in [Ca2+]i which was similar among the experimental groups of cells. However, when 1.5 mM Ca2+ was added, Ca2+ entry was significantly increased in cells cultured in HG compared to NG. This elevated Ca2+ entry in HG-treated cells was attenuated by treatment with LY341684. Cells treated with PMA in NG showed an increased Ca2+ entry similar to cells cultured in HG. Our results suggest that hyperglycemia enhanced Ca2+ entry in endothelial cells is PKC? dependent. Thus, PKC? inhibitors may restore normal endothelial cell function under hyperglycemic conditions. Supported by NIH/NIDCR.

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