Vascular calcification is recognized as an independent predictor of cardiovascular mortality, particularly in subjects with
chronic kidney disease. However, the pathways by which dysregulation of
lipid and
mineral metabolism simultaneously occur in this particular population remain unclear. We have shown that activation of the farnesoid X receptor (FXR) blocks mineralization of bovine calcifying vascular cells (CVCs) and in
ApoE knock-out mice with 5/6
nephrectomy. In contrast to FXR, this study showed that
liver X receptor (LXR) activation by LXR agonists and adenovirus-mediated LXR overexpression by VP16-LXRα and VP16-LXRβ accelerated mineralization of CVCs. Conversely, LXR inhibition by dominant negative (DN) forms of LXRα and LXRβ reduced
calcium content in CVCs. The regulation of mineralization by FXR and LXR agonists was highly correlated with changes in
lipid accumulation,
fatty acid synthesis, and the expression of
sterol regulatory
element binding protein-1 (SREBP-1). The rate of lipogenesis in CVCs through the
SREBP-1c dependent pathway was reduced by FXR activation, but increased by LXR activation.
SREBP-1c overexpression augmented mineralization in CVCs, whereas
SREBP-1c DN inhibited
alkaline phosphatase activity and mineralization induced by LXR agonists. LXR and
SREBP-1c activations increased, whereas FXR activation decreased, saturated and
monounsaturated fatty acids derived from lipogenesis. In addition, we found that
stearate markedly promoted mineralization of CVCs as compared with other
fatty acids. Furthermore, inhibition of either
acetyl-CoA carboxylase or
acyl-CoA synthetase reduced mineralization of CVCs, whereas inhibition of
stearoyl-CoA desaturase induced mineralization. Therefore, a
stearate metabolite derived from lipogenesis might be a risk factor for the development of
vascular calcification.