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Cerebral ischemia injury seriously endangers human health and its molecular mechanism is still not fully understood. has been reported to be involved in many physiological functions but the specific role of miRNA-223 in ischemic neuronal injury is still unclear. An oxygen-glucose deprivation and simulated reperfusion (OGD/R) model was constructed here to investigate the possible role miR-223 played in ischemic neuronal injury. The expression of miRNA-223 in the OGD/R model and its effect on cell proliferation were studied by qPCR and CCK8 assay. We observed that miR-223 was significantly over-expressed after OGD/R treatment and it suppressed significantly cortical neurons proliferation. To further study the mechanism involved, we predicted and examined the potential targets of miR-223 by targetscan, qPCR, western blot and luciferase reporter assay. We found that the expression level of type 1 insulin-like growth factor receptor (IGF1R) was negatively associated with the level of miR-223. Furthermore, the relative luciferase activity of pmirGLO-WT was inhibited obviously, while no significant change was observed in the pmirGLO-Mut group, indicating that miR-223 could bind to IGF1R. Similar cell proliferation suppression caused by miR-223 antagomir was observed when IGF1R was silenced. On the contrary, when cortical neurons were co-treated with miR-223 agomir and the cDNA of IGF1R which did not contain 3'-untranslated region, the inhibition caused by miR-223 disappeared. Our results suggested that miR-223 may suppress proliferation of cortical neurons that were treated with OGD/R via inhibiting IGF1R expression.

No abstract

The purpose of this study was to evaluate whether FGD5-AS1 participates in oxygen-glucose deprivation and simulated reperfusion (OGD/R)-induced neurons injury and the detailed mechanism. An OGD/R model was established using the primary cortical neuron isolated from the brains of Sprague-Dawley rats. qRT-PCR and western blot were performed to detect the RNA and protein expression levels, respectively. Cell counting kit 8 (CCK8) and flow cytometry assays were used to evaluate the proliferation and apoptosis of neurons. The luciferase reporter assay was used to verify the interaction between lncRNA FGD5-AS1 and miRNA-223. We found that the expression of FGD5-AS1 is decreased in neurons suffering from OGD/R. Up-regulation of FGD5-AS1 could recover proliferation and inhibit apoptosis of OGD/R-injured neurons. In addition, the interaction between FGD5-AS1 and miRNA-223 were verified. The expression of miRNA-223 was negatively correlated with the level of FGD5-AS1. In turn, the expression of insulin-like growth factor-1 receptor (IGFIR, a target gene of miR-223) was positively associated with the level of FGD5-AS1. Simultaneously down-regulating miR-223 and over-expressing FGD5-AS1 as well as IGF1R exhibited an additional effect of extenuating OGD/R damage i.e. increasing neuron proliferation and reducing neuron apoptosis. In conclusion, our findings indicated that FGD5-AS1 may protect the neuron against OGD/R injury via acting as a ceRNA for miR-223 to mediate IGF1R expression, which contributes to a deeper understanding of ischemic stroke and provide a promising therapeutic target for this disease.