Nicotinate-curcumin inhibits LPS-induced inflammatory cytokines secretion and ER stress in HUVECs

Abstract

Objective To investigate the effect of nicotinate-curcumin(NC) on the LPS-induced secretion of cytokines by human umbilical vein endothelial cell (HUVECs) and its mechanism. Methods HUVECs were incubated with different concentrations of NC for 24 h. Western blot was used to detect the phosphorylation of AMPK. After silencing the expression of AMPK with siRNA, the potential outcomes on the phosphorylation of NF-kappa B p65, the expression of adhesion molecules, the secretion of TNF-alpha and MCP-1 in the supernatant of LPS-induced cells, and the expression of endoplasmic reticulum stress markers IRE-1, eIF2α and CHOP were observed. Results The phosphorylation of AMPK was significantly increased and p65 phosphorylation was alleviated after HUVECs treatment with the concentration of 10~20 mmol/L NC for 24 h (P＜0.05). After silencing of AMPK, the inhibition effect of NC on NF-κB was significantly reduced(P＜0.05). At the same time, the expressions of ICAM-1, VCAM-1 and E-selectin, and the adhesion of THP-1 cells to HUVECs, content of TNF-α and MCP-1 in supernatants were significantly reduced after NC treatment (P＜0.05). After siRNA silenced AMPK, the above effects were all inhibited(P＜0.05). NC down-regulated the expression of endoplasmic reticulum stress markers IRE-1, eIF2α and CHOP induced by LPS. The inhibitory effect of curcumin on these molecules was significantly reduced by interfering with the expression of AMPK (P＜0.05). Conclusions NC inhibits LPS-induced expression, secretion of adhesion molecules and cytokines in HUVECs, and also inhibits endoplasmic reticulum stress. The mechanism is potentially related to the activation of AMPK.

Keywords

• nicotinate-curcumin|adenosine monophosphate-activate protein kinase|endoplasmic reticulum stress