VITAMIN D SUPPRESSES LIPOPOLYSACCHARIDES-INDUCED ENDOTHELIAL EXPRESSION OF ADHESION MOLECULES THROUGH PI3K/AKT/NF-KB SIGNALING PATHWAY

Wen Zhou¹, Qingsong Wang^{2, *}

¹Department of Histology and Embryology, Hainan Medical College, Haikou, 571199, China - ²Department of Biochemistry and Molecular Biology, Hainan Medical College, Haikou, 571199, China

Introduction: Adhesion molecules are key components for recruitment of leukocytes during the process of endothelial cell activation. The effects of vitamin D on the adhesion molecule expression in activated endothelial cells remain unclear. 

Materials and methods: human umbilical vein endothelial cells (HUVECs) were treated with or without 100nM 1,25(OH)₂D₃ for 24h. Then the cells were maintained with or without lipopolysaccharides (LPS) (5μg/mL) for 12h. Quantitative RT-PCR and western blotting were used to detect the LPS-activated transcription and expression of adhesion molecules (E-selectin, P-selectin, ICAM-1, VCAM-1) by HUVECs. ELISA was employed to examine the soluble isoforms of adhesion molecules. Further, phosphorylation levels of Akt Ser473 and Thr308, phosphorylation of IκBα phosphorylation and nuclear NF-κB accumulation were examined using western blotting.

Results: 1,25(OH)₂D₃ treatment ameliorated the expressions of E-selectin, P-selectin, ICAM-1 and VCAM-1 activated by LPS in HUVECs. 1,25(OH)₂D₃ treatment also suppressed upregulation of corresponding soluble isoforms of adhesion molecules in the cellular supernatant and inhibited LPS-stimulated PI3K/Akt/NF-κB signaling in HUVECs. Furthermore, the suppressive effect of 1,25(OH)₂D₃ on LPS-stimulated PI3K/Akt or NF-κB signaling was abrogated by PI3K inhibitor (Ly294002) or NF-κB inhibitor (BAY11-7082), and the inhibitory effect of 1,25(OH)₂D₃ on adhesion molecule expressions was subsequently blocked. 

Conclusion: 1,25(OH)₂D₃ inhibits LPS-activated expressions of adhesion molecules in HUVECs by suppressing PI3K/Akt/NF-κB pathway.