[Mechanism of salidroside in inhibiting expression of adhesion molecules in oxLDL-induced endothelial cells by regulating ferroptosis mediated by SIRT1/Nrf2]

Abstract

This article investigated the effect and mechanism of salidroside(SAL) on the expression of adhesion molecules in oxidized low-density lipoprotein(oxLDL)-induced mouse aortic endothelial cell(MAEC). The oxLDL-induced endothelial cell injury model was constructed, and the safe concentration and action time of SAL were screened. The cells were divided into control group, oxLDL group, low and high concentration groups of SAL, and ferrostatin-1(Fer-1) group. The cell viability was detected by CCK-8 assay; lactate dehydrogenase(LDH) leakage was measured by colorimetry; the expression of intercellular adhesion molecule 1(ICAM-1) and recombinant vascular cell adhesion molecule 1(VCAM-1) were detected by immunofluorescence; Fe~(2+),glutathione(GSH),malondialdehyde(MDA),and 4-hydroxynonenal(4-HNE) levels were detected by kit method; reactive oxygen species(ROS) was detected by DCFH-DA probe; the levels of glutathione peroxidase 4(GPX4),silent mating type information regulation 2 homolog 1(SIRT1), and nuclear factor erythroid 2-related factor 2(Nrf2) were determined by using Western blot. The inhibitors of Nrf2 and SIRT1 were used, and endothelial cell were divided into control group, oxLDL group, SAL group, ML385 group(Nrf2 inhibitor), and EX527 group(SIRT1 inhibitor). The ultrastructure of mitochondria was observed by electron microscope; mitochondrial membrane potential(MMP) was detected by flowcytometry; the expressions of SIRT1,Nrf2,solute carrier family 7 member 11(SLC7A11),GPX4,ferroportin 1(FPN1),ferritin heavy chain 1(FTH1),ICAM-1, and VCAM-1 were detected by Western blot. The results showed that similar to Fer-1,low and high concentrations of SAL could improve cell viability, inhibit LDH release and the expression of ICAM-1 and VCAM-1 in oxLDL-induced endothelial cells(P<0.05 or P<0.01). It was related to increase in GSH level, decrease in Fe~(2+),ROS,MDA, and 4-HNE level, and up-regulation of SIRT1,Nrf2, and GPX4 expression to inhibit ferroptosis(P<0.05 or P<0.01). The intervention effect of high concentration SAL was the most significant. ML385 and EX527 could partially offset the protection of SAL on mitochondrial structure and MMP and reverse the ability of SAL to up-regulate the expression of SIRT1,Nrf2,SLC7A11,GPX4,FPN1, and FTH1 and down-regulate the expression of ICAM-1 and VCAM-1(P<0.05 or P<0.01).To sum up, SAL could reduce the expression of ICAM-1 and VCAM-1 in oxLDL-induced endothelial cell, which may relate to activation of SLC7A11/GPX4 antioxidant signaling pathway mediated by SITR1/Nrf2, up-regulation of FPN1 and FTH1 expression, and inhibition of ferroptosis.

Keywords: ICAM-1; SIRT1/Nrf2/SLC7A11/GPX4 pathway; VCAM-1; ferroptosis; salidroside.