LncRNA MIR4697HG Alleviates Endothelial Cell Injury and Atherosclerosis Progression in Mice via the FUS/ANXA5 Axis

Atherosclerosis (AS) manifests with arterial intimal injury, lipid deposition and chronic inflammation, which is a key pathogenic cause of cardio-cerebrovascular disorders. LncRNA MIR4697HG was downregulated in human advanced atherosclerotic plaques. This study probed the precise biological functions and downstream regulatory mechanisms of MIR4697HG during AS progression. MIR4697HG levels in atherosclerotic plaque tissues and normal arterial intima were measured by RT-qPCR. An injury model of human umbilical vein endothelial cells (HUVECs) was induced through treating with oxidative low-density lipoprotein (ox-LDL). MIR4697HG overexpression plasmids (pcDNA-MIR4697HG) was transfected into ox-LDL-treated HUVECs, and then cell viability, apoptosis, reactive oxygen species (ROS) level, oxidative stress marker protein malondialdehyde (MDA) level and superoxide dismutase (SOD) activity, and adhesion molecule intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) levels in HUVECs were determined. Moreover, the binding between MIR4697HG and fused in sarcoma (FUS) was checked with RNA pull-down assay. The interaction between FUS and annexin A5 (ANXA5) was gauged with Co-immunoprecipitation. Then MIR4697HG/FUS/ANXA5 axis mediated HUVEC functions were accessed with rescue experiments. Additionally, an AS model was established via feeding a high-fat diet for ApoE(-/-) mice, and lentivirus MIR4697HG overexpression vector (Lv-MIR4697HG) was injected into AS mice followed by detection of atherosclerotic plaque area in mice. MIR4697HG was downregulated in atherosclerotic plaque tissues and HUVECs stimulated by ox-LDL. MIR4697HG overexpression attenuated ox-LDL-induced HUVEC viability inhibition, apoptosis, oxidative stress and adhesion molecule release. Moreover, MIR4697HG bound with FUS and facilitated FUS expression in HUVECs. FUS knockdown abrogated the functions of lncRNA MIR4697HG overexpression in ox-LDL induced HUVEC injury. Besides, FUS could bind with ANXA5. FUS overexpression inhibited ox-LDL induced HUVEC injury, while ANXA5 knockdown reversed these effects. Additionally, Lv-MIR4697HG reduced atherosclerotic plaque area in ApoE(-/-) mice. LncRNA MIR4697HG mitigated ox-LDL-induced apoptosis, oxidative stress and adhesion molecule release in HUVECs and alleviated AS progression in mice through the FUS/ANXA5 axis.