Galectin‐3 Aggravates Ox‐ldl‐induced Endothelial Dysfunction Through LOX‐1 Mediated Signaling Pathway

Galectin‐3, a biomarker linking oxidative stress and inflammation, participates in different mechanisms related to atherothrombosis, such as inflammation, proliferation, or macrophage chemotaxis. Accumulating evidence indicates that galectin‐3 may also promote atherogenesis through inducing endothelial dysfunction. Lectin‐like oxidized low‐density lipoprotein (oxLDL) receptor‐1 (LOX‐1), a receptor for oxLDL uptake, contributes to oxLDL‐induced endothelial dysfunction. Whether galectin‐3 induces endothelial dysfunction through modulation of LOX‐1‐mediated signaling remains unclear. In the present study, we explored the mechanisms underlying galectin‐3 enhanced cytotoxicity of oxLDL in human umbilical vein endothelial cells (HUVECs) and the role of LOX‐1. Incubation of HUVECs with galectin‐3 increased the expression of LOX‐1 in RNA and protein levels. In addition, the expression of LOX‐1 induced by oxLDL was promoted by galectin‐3. However, pretreatment of LOX‐1 antibody reduced LOX‐1 mRNA expression level in cells with oxLDL plus galectin‐3 incubation. Compared to cells treated with oxLDL alone, reactive oxygen species (ROS) generation via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation and subsequent activation of p38 mitogen‐activated protein kinases followed by nuclear factor kappa B (NF‐κB) activation and related inflammatory responses including adhesion molecule expression, adhesiveness of monocytic cells, and IL‐8 release were also aggravated in cells treated with galectin‐3 combined with oxLDL. Compared to cells treated with galectin‐3 plus oxLDL group. We found that LOX‐1 antibody mitigated NADPH oxidase activity, p‐38 up‐regulation, NF‐κB activation, and proinflammatory responses in cells treated with galectin‐3 combined with oxLDL. We conclude that galectin‐3 enhances endothelial LOX‐1 expression and propose a new mechanism by which galectin‐3 may promote endothelial dysfunction by inducing inflammation via LOX‐1/ROS/p38/NF‐κB‐mediated signaling pathway.