Affiliations: [a] Department of Cardiac Function, The First People’s Hospital of Lianyungang, The First Affiliated Hospital of Kangda College of Nanjing Medical University, Lianyungang City, Jiangsu, China
| [b] Department of Rehabilitation, Geriatric Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| [c] Department of Cardiovascular Division, The First People’s Hospital of Lianyungang, The First Affiliated Hospital of Kangda College of Nanjing Medical University, Lianyungang City, Jiangsu, China
Correspondence:
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Corresponding author: Hejian Song, Department of Cardiovascular Division, The First People’s Hospital of Lianyungang, The First Affiliated Hospital of Kangda College of Nanjing Medical University, No. 182 North Tongguan Road, Haizhou, Lianyungang, Jiangsu, China. Tel.: +86 518 85605248; E-mail: hjsong660758@21cn.com.
Note: [1] These authors contributed equally to this work.
Abstract: BACKGROUND:Previous data have shown that circ_0033596 is involved in the pathogenesis of atherosclerosis (AS). The study aims to reveal the detailed mechanism of circ_0033596 in AS. METHODS:Human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL) to establish an AS cell model. Quantitative real-time polymerase chain reaction and western blot were implemented to detect the expression of circ_0033596, miR-637, growth factor receptor bound protein2 (GRB2), BCL2-associated x protein (Bax) and B-cell lymphoma-2 (Bcl-2). Cell viability, proliferation, apoptosis and tube formation were investigated by cell counting kit-8, EdU assay, flow cytometry and tube formation assay, respectively. The production of interleukin (IL-6) and tumor necrosis factor-α (TNF-α) was evaluated by enzyme-linked immunosorbent assay. Oxidative stress was evaluated by lipid peroxidation malondialdehyde assay kit and superoxide dismutase activity assay kit. Dual-luciferase reporter assay, RNA pull-down assay and RIP assay were performed to identify the associations among circ_0033596, miR-637 and GRB2. RESULTS:The expression of circ_0033596 and GRB2 was significantly increased, while miR-637 was decreased in the blood of AS patients and ox-LDL-induced HUVECs compared with controls. Ox-LDL treatment inhibited HUVEC viability, proliferation and angiogenic ability and induced cell apoptosis, inflammation and oxidative stress, while these effects were attenuated after circ_0033596 knockdown. Circ_0033596 interacted with miR-637 and regulated ox-LDL-induced HUVEC damage by targeting miR-637. In addition, GRB2, a target gene of miR-637, participated in ox-LDL-induced HUVEC injury by combining with miR-637. Importantly, circ_0033596 activated GRB2 by interacting with miR-637. CONCLUSION:Circ_0033596 depletion protected against ox-LDL-induced HUVEC injury by miR-637/GRB2 pathway, providing a therapeutic target for AS.
