SiLOXL2 inhibits endothelial inflammatory response and EndMT induced by Ox-LDL.

Abstract

Our research aimed to investigate the potential role and mechanism of lysyl oxidase (LOX)-like-2 (LOXL2) in atherosclerosis (AS) by using the human umbilical vein endothelial cells (HUVECs) stimulated by oxidized low-density lipoprotein (ox-LDL). HUVECs were treated with ox-LDL at different concentrations (0, 10, 25, 50, and 100 μg/mL) and incubated for 24 hours. The transfection efficacy of siLOXL2 was investigated by western blot and RT-qPCR. Cell migration, intracellular ROS measurement, oxidative stress, ELISA, and adhesion assays were carried out to examine the ox-LDL-induced HUVECs injury. RT-qPCR and Western blot were used to determine gene and protein expression levels. LOXL2 protein expression increased in ox‑LDL‑induced endothelial cells. Ox-LDL+siLOXL2 significantly inhibited the migration ability of HUVECs and reduced the expression of vascular endothelial growth factor A (VEGFA) and matrix metalloproteinase 9 (MMP-9) gene expressions (all, P <0.05). The ox-LDL+siLOXL2 significantly reduced intracellular ROS production and inhibited the expression of Malondialdehyde (MDA), whereas it markedly enhanced superoxide dismutase (SOD) and catalase (CAT) (all, P <0.05). Supernatant levels of Interleukin-1 beta (IL-1β), Interleukin 6 (IL-6), and Tumor necrosis factor alpha (TNF-α) were significantly attenuated by the ox-LDL+siLOXL2 treatment (all, P <0.05). Ox-LDL+siLOXL2 markedly suppressed the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) (all, P <0.05). ox-LDL+siLOXL2 treatment remarkably reduced the expression of α-smooth muscle actin (α‑SMA) and Vimentin, while increased CD31 and von Willebrand factor (vWF) gene expression (all, P <0.05). LOXL2 silencing is protected against ox-LDL-induced endothelial cell dysfunction, and the mechanism may be related to the inhibition of the EndMT pathway.