Downregulation of MicroRNA-4463 Attenuates High-Glucose- and Hypoxia-Induced Endothelial Cell Injury by Targeting PNUTS

Abstract

Background/Aims: Vascular complications are the main reasons for disability and mortality associated with type 2 diabetes mellitus (T2DM) and numerous microRNAs (miRNAs) are involved in this process. Our previous study demonstrated that miR-4463 was increased in the plasma of T2DM patients combined with arteriosclerosis of low extremity artery (ASO). However, the role of miR-4463 remains unclear. Methods: miR-4463 expression in the vascular tissues of patients with ASO and T2DM and in human umbilical vein endothelial cells (HUVECs) was detected by qPCR. Cell survival and apoptosis was analyzed via Cell Counting Kit-8 and flow cytometry assays, respectively. Protein expression was determined by Western blot and protein subcellular localization was detected with immunofluorescence. A dual-luciferase assay was used to elucidate the target gene of miR-4463. Results: miR-4463 was elevated in the vascular tissues of patients with T2DM and ASO. In HUVECs, both 25 mmol/L glucose (high glucose, HG) and hypoxia induced miR-4463 expression. Downregulation of miR-4463 promoted HUVEC survival and reduced cell apoptosis under HG and/or hypoxic conditions by facilitating the expression of protein phosphatase-1 nuclear targeting subunit (PNUTS), X-linked inhibitor of apoptosis protein (XIAP), p-AKT, p-Bad, increased the Bcl-2/Bax ratio, as well as downregulated cleaved caspase 3 expression. Mechanistically, we identified PNUTS as a direct target gene of miR-4463. Both the inhibition of AKT phosphorylation and silencing of PNUTS diminished the effect of miR-4463 on HUVEC apoptosis. Moreover, downregulation of miR-4463 enhanced PNUTS to enable PTEN nuclear localization, which resulted in AKT phosphorylation. Conclusion: Our results suggest that downregulation of miR-4463 attenuates cell apoptosis by directly enhancing PNUTS expression to promote PTEN nuclear localization, subsequently activating AKT signaling pathway in HUVECs under HG and/ or hypoxic conditions.

miR-4463 regulates aromatase expression and activity for 17β-estradiol synthesis in response to follicle-stimulating hormone

“…The upregulation of miR-4463 expression enhanced H 2 O 2 -induced oxidative stress and promotes apoptosis in endothelial cells [ 52 ]. The inhibition of miR-4463 promoted human umbilical vein endothelial cell survival and reduced apoptosis under hypoxic conditions by targeting the protein phosphatase-1 nuclear targeting subunit [ 53 ]. In addition, miR-4463 promoted vascular smooth muscle cell migration, which is implicated in vascular diseases, by targeting angiomotin [ 54 ].…”

Down‐regulation of miR‐383‐5p suppresses apoptosis in oxidative stress rat hepatocytes by targeting Bcl2

“…H 2 O 2 was added exogenously and shown to be the most convenient and effective method to construct oxidative stress models in different cells. H 2 O 2 is a ROS, which can enter the cell through the membrane and change the normal physiologic state of the cell (He et al, 2018). Studies have shown that ROS can induce apoptosis through the mitochondrial apoptotic pathway and activation of the NF‐κB and SAPK signalling pathways (Dhupal et al, 2018; Tanaka et al 2018; Yang et al 2018).…”

Regulatory MicroRNAs in T2DM and Breast Cancer

“…miRNAs have also been associated with diabetic complications. For example, the expression of miR-4463 is elevated in T2DM patients with arteriosclerosis [96]. It was shown to attenuate cell apoptosis via peanut (PNUT)-mediated PTEN nuclear localization and the activation of the cell survival PI3K/AKT pathway in hypoxic and/or hyperglycemic endothelial cells.…”