Signaling pathway involved in hypoxia-inducible factor-1α regulation in hypoxic-ischemic cortical neurons in vitro

Hypoxia-inducible factor-1α (HIF-1α) is a key transciptional regulator of cellular and systemic oxygen homeostasis. Previous studies have shown that the regulation of HIF-1α is involved in the activation of PI3K/Akt pathway in some cells. However, whether this pathway plays a role in modulating HIF-1α in cultured cortical neurons during hypoxia-ischemia (HI) remains unclear. We therefore investigated the relationship between phosphoinositid 3-kinase/Akt (PI3K/Akt) pathway and HIF-1α expression in cultured neurons using an oxygen and glucose deprivation (OGD) model. In this study, cortical neurons cultured in vitro were subjected to OGD for 3 h followed by reperfusion. The expressions of HIF-1α, VEGF, total Akt and phosphorelated-Akt (p-Akt) were detected by RT-PCR, Western blot and immunocytochemistry. We found that HIF-1α and VEGF were increased at 4 h and peaked at 8 h after OGD. Meanwhile, p-Akt increased and peaked at 4 h after reperfusion, preceding HIF-1α expression. Pretreatment with wortmannin, a PI3K/Akt pathway inhibitor, significantly inhibited p-Akt expression and further attenuated both transcription and translation of HIF-1α and VEGF. Collectively, our findings suggested that PI3K/Akt signaling pathway might be involved in HIF-1α regulation after OGD in cultured cortical neurons.