1α,25-dihydroxyvitamin D3 inhibits tumor necrosis factor-α induced activation of human umbilical vein endothelial cells via NF-κB signaling pathway / 中华内分泌代谢杂志

ABSTRACT

Objective To investigate the effect of 1α, 25-dihydroxyvitamin D3 [1α,25-(OH)2 D3] on tumor necrosis factor-α ( TNF-α) induced activation of human umbilical vein endothelial cells ( HUVECs ) . The mechanism involved in this process was also studied. Methods HUVECs were cultured and treated with TNF-α( 40 ng/ml), 1α,25-(OH)2D3(10-8 mol/L), and SN50 as indicated. Vascular cell adhesion molecule (VCAM) and E-selectin were used as markers of endothelial activation, which were detected by Western blotting and realtime PCR (RT-PCR). NF-κB signaling pathway was investigated to study the mechanism. Western blotting, RT-PCR, immunofluorescence assay, and chromatin immunoprecipitation ( ChIP ) method were used to evaluate the effects of 1α,25-( OH) 2 D3 on its early activation, nuclear transport, and binding to VCAM and E-selectin promoters. Results (1) Western blotting and RT-PCR showed that TNF-α could significantly up-regulate the expression of VCAM and E-selectin in HUVECs, which can be inhibited by specific NF-κB blocker SN50. 1α,25-( OH) 2 D3 down-regulated the expression of VCAM and E-selectin induced by TNF-α. ( 2 ) Western blotting showed that TNF-α induces I-κBαphosphorylation, thereby activating NF-κB p65 subunit. Immunofluorescence showed that 1α, 25-( OH ) 2 D3 significantly inhibited the nuclear translocation of NF-κB p65 subunit. ChIP analysis revealed that 1α,25-( OH) 2 D3 inhibited the binding of NF-κB p65 to VCAM and E-selectin promoters and thus affected gene expression. Conclusions TNF-αenhanced the expression of E-selectin and VCAM in HUVECs via NF-κB signaling pathway. 1α,25-( OH) 2 D3 may inhibit NF-κB early activation, nuclear transport and the binding of NF-κB p65 to VCAM and E-selectin promoters, thereby inhibiting TNF-α-induced endothelial cell activation.