MicroRNA‑199a‑5p aggravates primary hypertension by damaging vascular endothelial cells through inhibition of autophagy and promotion of apoptosis

The present study investigated the expression of microRNA (miRNA or miR)-199a-5p in the peripheral blood of patients with primary hypertension, and examined its mechanism of action in vascular endothelial cell injury induced by hypertension. A total of 57 patients with primary hypertension, who were treated at the Affiliated Hospital of Qingdao University (Qingdao, China) between December 2014 and November 2015 were included in the present study. Peripheral blood was collected from all patients. The expression of miR-199a-5p was measured using reverse-transcription quantitative polymerase chain reaction analysis. Human umbilical vein endothelial cells (HUVECs) were divided into negative control, miR-199a-5p mimics and rescue (co-transfected with miR-199a-5p mimics and inhibitor) groups. After transfection, the proliferation and apoptosis of HUVECs were evaluated by a Cell Counting Kit-8 assay, a bromodeoxyuridine incorporation assay and flow cytometry. Western blot analysis was used to determine the expression of proteins involved in autophagy-associated and adenosine monophosphate kinase (AMPK)/unc-51 like autophagy activating kinase 1 (ULK1) signaling pathways. Laser scanning confocal microscopy and electron microscopy were used to observe the autophagy of HUVECs. The expression of miR-199a-5p was elevated in peripheral blood of patients with hypertension, and was correlated with the progression of hypertension. Overexpression of miR-199a-5p inhibited the proliferation and promoted the apoptosis of HUVECs. Upon expression of miR-199a-5p, the transition between microtubule-associated proteins 1A/1B light chain 3B (LC3B)I and LC3BII proteins was inhibited, the expression of p62 protein was upregulated. In addition, miR-199a-5p decreased the numbers of autophagosomes and autolysosomes in HUVECs. The present study demonstrated that expression of miR-199a-5p is positively correlated with the severity of hypertension. Expression of miR-199a-5p aggravated vascular endothelial injury by inhibiting autophagy and promoting the apoptosis of HUVECs via downregulation of the AMPK/ULK1 signaling pathway.