Astaxanthin suppresses End MT by LOX-1 pathway in ox-LDL-induced HUVECs

IntroductionAstaxanthin (ASX) is carotenoid with the highest antioxidant activity in various cell types and reverse atherosclerosis. However, the roles and detailed mechanisms of ASX in atherosclerosis associated endothelial injury remains unclear.MethodsIn vitro atherosclerosis model was established in HUVECs by incubation with oxidized low-density lipoprotein (ox-LDL). Cell viability and oxidative stress were measured. The mRNA and protein expressions of lectin-like ox-LDL receptor (LOX-1) and other related genes were determined.Resultsox-LDL reduced cell viability of HUVECs, and induced oxidative stress, as evidenced by elevated cellular malondialdehyde (MDA) and decreased superoxide dismutase (SOD). Pretreatment with ASX (50, 100, 200, and 400 mu M) markedly reversed the reduction in cell viability and an increase in migration of HUVECs induced by ox-LDL (50 mu g/mL). ASX attenuated the increase in the endothelial-to-mesenchymal transition (EndMT) process, as evidenced by increased CD31 and decreased alpha-SMA and vimentin proteins by ASX treatment in HUVECs. Furthermore, ASX attenuated the increase in MDA and decrease in SOD induced by ox-LDL, increased supernatant NO production, attenuated the increase in iNOS and decrease in eNOS in HUVECs with ox-LDL. ASX enhanced mRNA and protein expressions of the lectin-like ox-LDL receptor (LOX-1), which was dependent on ASX's antioxidant activity. The inhibitory effect of ASX on EndMT could be abolished by overexpression of LOX-1 in HUVECs induced by ox-LDL.ConclusionsOur data speculate that ASX prevents ox-LDL-induced endothelial cell injury and EndMT by inducing antioxidant property (SOD and NO) and decreasing LOX-1 expression.