Long-chain noncoding RNA GAS5 mediates oxidative stress in cardiac microvascular endothelial cells injury

This study is performed to figure out the role of long-chain noncoding RNA growth-arrest specific transcript 5 (GAS5) in homocysteine (HCY)-induced cardiac microvascular endothelial cells (CMECs) injury. CMECs were cultured and the model of CMECs injury was established by coincubation with HCY. To construct stable overexpression of GAS5 cells, the expression of GAS5, microRNA-33a-5p (miR-33a-5p) and ATP-binding cassette transporter A1 (ABCA1), and biological characteristics of cells were determined. The messenger RNA (mRNA) level and secretion of vascular endothelial growth factor (VEGF), activity of reactive oxygen species (ROS) and superoxide dismutase (SOD), and the content of malondialdehyde (MDA) were measured. The binding site between GAS5 and miR-33a-5p and between miR-33a-5p and ABCA1 was verified. CMECs were successfully cultured. Reduction of GAS5 expression and ABCA1 expression together with increased expression of miR-33a-5p was found in CMECs induced by HCY. After overexpression of GAS5, there showed increased proliferative activity, decreased cell apoptosis rate and apoptosis index, enhanced cell migration ability, increased number of lumen formation, increased mRNA expression of VEGF in cells and the secretion in the supernatant, decreased activity of ROS and SOD in cells, and decreased content of ROS in cells. miR-33a-5p could promote the enrichment of GAS5 and ABCA1 was the direct target gene of miR-33a-5p. Our study suggests that the low expression of GAS5 was observed in HCY-induced CMECs injury, and the upregulation of GAS5 could attenuate HCY-induced CMECs injury by mediating oxidative stress, and its mechanism is related to the upregulation of ABCA1 expression by competitively binding with miR-33a-5p.