TGF-β Signaling Induces the Expression of OPN in Blood Vessel Endothelial Cells

The mechanism of blood vessel formation and degeneration still remains unclear. Transforming growth factor-β1 (TGF-β1) signaling is a critical pathway in this progression and can induce multiple biological effects. Osteopontin (OPN) is involved in mineral metabolism and the inflammatory response associated with vascular calcification.To identify the relationship between TGF-β signaling pathway and OPN, we stimulated human vascular endothelial cells (HVECs) and human aortic endothelial cells (HAECs) using various concentration of TGF-β1 in vitro.As assessed by flow cytometry and western blots, apoptosis levels were significantly increased with TGF-β1 treatment. We also demonstrated that OPN increased in vitro with TGF-β signaling by western blot and quantitative real time polymerase chain reaction (qRT-PCR) analyses. The inhibitory phosphorylation of endothelial nitric-oxide synthase (eNOS) (Thr495) was also up-regulated by TGF-β signaling. Meanwhile, the anti-inflammatory factor Nrf2 and the activating phosphorylation of eNOS (Ser1177) were down-regulated.Taken together, our findings demonstrate that TGF-β signaling can induce the expression of OPN, which may play an important role in the dysfunction of the vascular wall.