Activation of vitamin D receptor promotes VEGF and CuZn-SOD expression in endothelial cells.
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ABSTRACT: Endothelial dysfunction associated with vitamin D deficiency has been linked to many chronic vascular diseases. Vitamin D elicits its bioactive actions by binding to its receptor, vitamin D receptor (VDR), on target cells and organs. In the present study, we investigated the role of VDR in response to 1,25(OH)?D? stimulation and oxidative stress challenge in endothelial cells. We found that 1,25(OH)?D? not only induced a dose- and time-dependent increase in VDR expression, but also induced up-regulation of vascular endothelial growth factor (VEGF) and its receptors (Flt-1 and KDR), as well as antioxidant CuZn-superoxide dismutase (CuZn-SOD) expression in endothelial cells. We demonstrated that inhibition of VDR by VDR siRNA blocked 1,25(OH)?D? induced increased VEGF and KDR expression and prevented 1,25(OH)?D? induced endothelial proliferation/migration. Using CoCl?, a hypoxic mimicking agent, we found that hypoxia/oxidative stress not only reduced CuZn-SOD expression, but also down-regulated VDR expression in endothelial cells, which could be prevented by addition of 1,25(OH)?D3 in culture. These findings are important indicating that VDR expression is inducible in endothelial cells and oxidative stress down-regulates VDR expression in endothelial cells. We conclude that sufficient vitamin D levels and proper VDR expression are fundamental for angiogenic and oxidative defense function in endothelial cells.
SUBMITTER: Zhong W
PROVIDER: S-EPMC3915503 | biostudies-literature | 2014 Mar
REPOSITORIES: biostudies-literature
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