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A role for PKCβ in altering calcium homeostasis under hyperglycemic conditions in human endothelial cells
Author(s) -
Zhang Rui,
Thor Der,
Chaharmahali Pegah,
Anderson Leigh,
Rahimian Roshanak
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.840.10
Subject(s) - protein kinase c , thapsigargin , endocrinology , medicine , activator (genetics) , extracellular , homeostasis , calcium , endothelial stem cell , cell culture , chemistry , intracellular , fura 2 , calcium in biology , phorbol , microbiology and biotechnology , biology , kinase , biochemistry , cytosol , receptor , enzyme , in vitro , genetics
Cardiovascular diseases (CVD) are leading causes of morbidity and mortality for diabetic patients. Endothelial cell dysfunction is a hallmark of CVD. Intracellular Ca 2+ concentration ([Ca 2+ ] i ) may regulate endothelial cell function. Here, we investigated the effects of hyperglycemia on [Ca 2+ ] i and a role for protein kinase C (PKC) in regulating [Ca 2+ ] 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 PKCβ inhibitor, 100 nM, 24h), or c) phorbol 12‐myristate 13‐acetate (PMA, PKC activator, 200 nM, 4h). Using a spectrofluorometer, [Ca 2+ ] i in cells loaded with Fura 2‐AM was monitored in the absence of extracellular Ca 2+ . Thapsigargin (SERCA inhibitor, 1 μM,) induced a transient increase in [Ca 2+ ] i which was similar among the experimental groups of cells. However, when 1.5 mM Ca 2+ was added, Ca 2+ entry was significantly increased in cells cultured in HG compared to NG. This elevated Ca 2+ entry in HG‐treated cells was attenuated by treatment with LY341684. Cells treated with PMA in NG showed an increased Ca 2+ entry similar to cells cultured in HG. Our results suggest that hyperglycemia enhanced Ca 2+ entry in endothelial cells is PKCβ dependent. Thus, PKCβ inhibitors may restore normal endothelial cell function under hyperglycemic conditions. Supported by NIH/NIDCR.