Knockdown of circ_0007290 alleviates oxygen-glucose deprivation-induced neuronal injury by regulating miR-496/PDCD4 axis

Circular RNAs (circRNAs) are highly enriched in the brain and involved in many types of central nervous system pathologies. Herein, this study aimed to investigate the role and mechanism of circ_0007290 in ischemic stroke. The oxygen-glucose deprivation (OGD) model was established with the HCN-2 cells in vitro. Levels of genes and proteins was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. In vitro experiments were conducted using cell counting kit-8 (CCK-8) assay, EdU (5-ethynyl-2’-deoxyuridine) assay, flow cytometry and ELISA, respectively. The levels of lactate dehydrogenase (LDH) were measured using the commercial kit. RNA pull-down and dual-luciferase reporter assay were used to identify the target relationship between miR-496 and circ_0007290 or PDCD4 (programmed cell death protein 4). Circ_0007290 expression was elevated in acute ischemic stroke (AIS) patients and OGD-induced cell injury model. OGD stimulation induced neuronal apoptosis, promoted LDH release, and enhanced inflammation in HCN-2 cells, which all were reversed by the knockdown of circ_0007290. Mechanistically, circ_0007290 served as a sponge for miR-496 to relieve the repression of miR-496 on the expression of its target PDCD4. Moreover, miR-496 inhibition or PDCD4 overexpression abolished the inhibitory effects of circ_0007290 knockdown OGD-evoked neuronal injury. Knockdown of circ_0007290 alleviated OGD-induced neuronal injury by regulating miR-496/PDCD4 axis, providing a novel insight into the pathology of ischemic stroke.