During hypoxia the degradation of HIF selleck Tubacin 1 is inhibited, and then HIF 1 heterodimerizes with HIF 1B and translocates to the nucleus. HIF 1 B dimer binds to hypoxia response elements and activates target genes transcription, including heme oxygenase 1, erythropoietin, vascular endothelial growth factor, and various glycolytic enzymes that contribute to adaptation to hypoxia and or ischemia. Therefore HIF 1 plays a key role in hypoxic ischemic response. Recent studies indicate that miRNAs play important roles in hypoxia ischemia. MiR 494 has been reported to be significantly increased in ex vivo ischemia reperfusion mouse hearts. Moreover, miR 494 has cardiopro tective effects against ischemia reperfusion induced injury by targeting both proapoptotic proteins and antiapoptotic proteins to active the Akt mitochondrial signaling pathway.

Obviously, HIF 1 plays an important role in hypoxia and or ischemia conditions. Studies have shown that Akt can augment HIF 1 expression by increasing its translation under both normoxic and hypoxic conditions. However, the potential link between miR 494 and HIF 1 is unknown. We hypothesize that miR 494 may have a role in influen cing HIF 1 expression and contribute to the cellular re sponse to hypoxia. Simultaneously, almost all previous studies about miR 494 were implemented in tumour cells or myocardial cell. The role of miR 494 in liver cell was unclear. Therefore, the present study was undertaken to investigate the influence of miR 494 on HIF 1 expression and its relative mechanism in human hepatic cell line L02.

We also investigated the function of miR 494 in response to hypoxia induced apoptosis. Our results showed that miR 494 were upregulated up to peak after 4 h of hypoxia in the L02 human hepatic cell line. Furthermore, we found that overexpression of miR 494 increased the of expres sion HIF 1 through activating the PI3K Akt signaling pathway and protected against hypoxia induced apoptosis in the immortalized hepatocyte cell line L02. Methods Cell culture The L02 human hepatic cell line purchased from China Center for Type Culture Collection was cultured in RPMI 1640 medium supplemented with 10% fetal bovine serum. Cells were grown under normoxic or hypoxic conditions at 37 C 5% CO2. Specially, medium was replaced with Dulbeccos modified Eagles medium without serum and glucose during hypoxia.

To block PI3K Akt signaling pathway, LY294002 was added to the culture medium. MiRNA and cell transfection MiR 494 mimic and the negative control were obtained from RiboBio. The miR 494 overexpression study was performed using miR 494 mimic and its negative control. Cells were cultured Drug_discovery to 30 50% confluence, and transfected with miR 494 mimic and negative control using Lipofectamine 2000 in serum free Opti MEM medium according to the manufacturers instruction. Cells were cultured in fresh medium containing 10% FBS after transfection.