1α, 25-dihydroxyvitamin D3 attenuates tumor necrosis factor-α-induced endothelial cell injury by modulating the tumor necrosis factor-α/nuclear factor kappa-B pathway.

OBJECTIVE: Cardiovascular (CV) diseases remain the leading cause of death in modern societies, with endothelial dysfunction being the common pathology of CV diseases with various etiologies. Therefore, effectively regulating the function of endothelial cells is considered the key to the future treatment of various CV diseases. Low levels of vitamin D and its analogs have been shown to be associated with endothelial dysfunction in various diseases. However, the underlying mechanism remains unknown. Here, we conducted an in vitro study to evaluate the effects of 1α,25-dihydroxyvitamin D3 (1α, 25(OH)2D3), the active form of vitamin D, on adhesion molecule expression in human endothelial cells. The possible mechanism involved in this process was also explored. MATERIAL AND METHODS: Human umbilical vein endothelial cells were cultured and treated according to the experimental requirements. Western blotting and reverse transcription polymerase chain reaction were used to evaluate the expression of vascular cell adhesion molecule-1 (VCAM-1) and E-selectin. Chromatin immunoprecipitation (ChIP) assays, immunofluorescence, Western blotting, and coimmunoprecipitation were used to assess the effects of 1α, 25(OH)2D3 on nuclear factor kappa-B (NF-κB) signaling. RESULTS: 1α, 25(OH)2D3 inhibited VCAM-1 and E-selectin mRNA and protein expression after tumor necrosis factor-α (TNF-α) stimulation. Moreover, 1α, 25(OH)2D3 affected TNF-α-induced IκBα phosphorylation and p65 NF-κB activation, leading to the inhibition of p65 expression. A ChIP assay revealed that TNF-α increased p65 binding to the promoters of VCAM-1 and E-selectin, which was suppressed by 1α, 25(OH)2D3. These effects were abrogated by a specific vitamin D receptor siRNA (VDR-siRNA). Coimmunoprecipitation revealed that 1α, 25(OH)2D3 induced increased binding of the vitamin D receptor to p65, which inhibited the ability of p65 to bind to target gene promoters. CONCLUSION: 1α, 25(OH)2D3 regulates adhesion molecule expression in endothelial cells through the TNF-α/NF-κB pathway, laying the foundation for the clinical application of 1α, 25(OH)2D3 in the treatment of CV diseases.