miR‑140‑5p regulates angiogenesis following ischemic stroke by targeting VEGFA

MicroRNA (miRNA or miR) expression profiles are altered in tissues under hypoxic-ischemic conditions. The expression of miR‑140 is downregulated >2-fold following hypoxic-ischemic brain damage, however, its role in angiogenesis subsequent to cerebral ischemia is not fully understood. The present study aimed to investigate the role of miR-140-5p in angiogenesis and the molecular mechanism mediated by vascular endothelial growth factor A (VEGFA) in an in vitro model for brain ischemia. A rat middle cerebral artery occlusion (MCAO) model was constructed, and the results from reverse transcription-quantitative polymerase chain reaction and western blot analysis demonstrated that the expression levels of miR-140‑5p were significantly decreased, while the expression levels of VEGFA were significantly increased between 12 and 48 h in the rat cerebral following MCAO. Furthermore, human umbilical vein endothelial cells (HUVECs) were exposed to low oxygen conditions and it was demonstrated that hypoxia downregulated miR-140-5p and upregulated VEGFA expression levels. The miR-140-5p mimic was transfected into the normoxic and hypoxic HUVECs and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Transwell migration and tube formation assays were performed. The results indicated that miR‑140‑5p inhibited angiogenesis by decreasing cell proliferation, migration and tube formation. Additionally, in human embryonic kidney 293 cells, results from the luciferase reporter assay revealed that miR‑140‑5p directly targeted the 3' untranslated region of VEGFA and that miR‑140‑5p regulated the protein expression of VEGFA. To further analyze this effect, a VEGFA‑pEGFP‑C1 plasmid was transfected into the normoxic and hypoxic HUVECs, and it was revealed that the inhibitory effect of miR‑140‑5p on angiogenesis was attenuated by the overexpression of VEGFA. In conclusion, to the best of our knowledge, the present study is the first to suggest that miR‑140‑5p exerts an inhibitory effect on angiogenesis in an in vitro model of ischemia, and this effect is achieved partially by targeting VEGFA. The present study provided a novel biomarker for the treatment of cerebral ischemia.