the effect of adiponectin on osteonectin gene expression by oxidized low density lipoprotein-treated vascular smooth muscle cells

osteonectin is a bone- associated protein involved in vascular calcification. adiponectin may protect against cardiovascular disease but possible effects on vascular calcification have been poorly studied. the aim of this study was to investigate the modulatory effect of adiponectin on oxidized low density lipoprotein (oxldl)- induced expression of osteonectin in human aorta vascular smooth muscle cells (ha/vsmcs). ha/vsmcs were cultured in f12k media and then treated with oxldl (100 µg/ml) in the presence or absence of adoponectin (5 µg/ml) for 24 and 48 hours. mrna expression and protein level of osteonectin were determined by quantitative real-time pcr and western blot analysis, respectively. after exposure to oxldl, osteonectin expression increased 1.62 ± 0.23- and 6.62 ± 0.48-fold after 24 and 48 hours respectively compared to the control. adiponectin increased oxldl- induced osteonectin expression in a time-dependent manner after 24 and 48 hours (3.24 ± 0.39- and 24.93 ± 2.15-fold, respectively). western blotting confirmed that osteonectin protein was upregulated by adiponectin.our data suggest that oxldl might cause the increase of osteonectin expression both at mrna and protein level. this upregulation is intensified by adiponectin.