Salusin-alpha Attenuates Inflammatory Responses in Vascular Endothelial Cells

Abstract

Atherosclerosis accounts for numerous cardiovascular diseases, and cytokines have a critical role in acceleration or suppression of disease. Salusin-alpha presents a new class of bioactive peptides that can have anti-atherogenic properties. Therefore, the effects of salusin-alpha on the expression of some pro- and anti-inflammatory cytokines and on TNF-alpha-induced inflammatory responses in human umbilical vein endothelial cells (HUVECs) were examined. The involvement of the NF-kappa B pathway in effects of salusin-alpha in HUVECs was checked using Bay 11-7082 as an NF-kappa B inhibitor. The mRNA expression of pro-inflammatory cytokines including IL-6, IL-8, and IL-18 and anti-inflammatory cytokine IL-1Ra was assessed by real-time PCR. The protein levels of cytokines were measured by the ELISA method. Salusin-alpha suppressed both mRNA and protein expression of pro-inflammatory cytokines and induced mRNA and protein expression of IL-1Ra in HUVECs. Salusin-alpha suppressed TNF-alpha-induced inflammatory responses in HUVECs. The down-regulatory or up-regulatory effects of salusin-alpha on expression of cytokines could not be influenced by Bay 11-7082 pretreatment. Our findings indicate anti-inflammatory effects of salusin-alpha and suggest a novel peptide-based therapeutic strategy for atherosclerosis.