Expression of microRNA-150 targeting vascular endothelial growth factor-A is downregulated under hypoxia during liver...

Vascular endothelial growth factor (VEGF) is a factor that stimulates the proliferation of sinusoidal endothelial cells and hepatocytes during liver regeneration (LR). The present study aimed to screen and validate a microRNA (miRNA) that targets VEGF-A with relative specificity and to elucidate the potential association between hypoxia-inducible factor-1α (HIF‑1α) and miRNA expression in the early phase of LR. Changes in the expression of miRNAs, which were predicted to target VEGF-A using online databases, were detected at 12, 24 and 48 h following a 70% partial hepatectomy (PHx) using quantitative PCR (qPCR). An inhibitor of the most downregulated miRNA was transfected into the primary hepatocytes in order to observe changes in the expression of the VEGF-A gene. The expression of HIF-1α protein in the regenerating liver was investigated using western blot analysis. The expression levels of HIF-1α mRNA (messenger RNA), the selected miRNA and VEGF-A mRNA in an anoxic model of hepatocytes was examined with qPCR. Of seven putative miRNAs, the expression of miR-150 exhibited the sharpest downregulation from 12-48 h. The micrOFF™ miR-150 inhibitor significantly elevated the expression levels of VEGF-A mRNA and protein 48 h after transfection. Thus, VEGF-A may be a downstream target of miR-150 during LR. Furthermore, HIF-1α protein expression increased to its highest level 24 h following PHx. miR-150 expression was inhibited and the expression of VEGF-A mRNA increased accordingly in the hypoxia-induced hepatocytes. Our results suggest that miR-150 expression is subject to negative regulation by HIF-1α.