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

Abstract

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 48h 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 12-48h. The micrOFF™ miR-150 inhibitor significantly elevated the expression levels of VEGF-A mRNA and protein 48h 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 24h 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.