The pathophysiology of hyperuricemia in essential hypertension: a pilot study

High Concentrations of Uric Acid Inhibit Endothelial Cell Migration via miR-663 Which Regulates Phosphatase and Tensin Homolog by Targeting Transforming Growth Factor-β1

BACKGROUND

Whether microRNAs participate in endothelial dysfunction HUA remains unknown. A previous study indicated that miR-663 was the most significantly differentially expressed endothelial microRNA under HUA conditions. Some studies have demonstrated that the miR-663 target gene and TGF-β1, promoted endothelial cell migration by inhibiting PTEN deleted on chromosome 10. Therefore, we hypothesized that HUA inhibits endothelial migration via miR-663, which regulates PTEN by targeting TGF-β1.

METHODS

PCR analysis was performed to determine miR-663 expression levels. A luciferase assay was performed to validate whether miR-663 targets TGF-β1 directly. Western blot analysis was performed to determine TGF-β1 and PTEN expression levels. An miR-663 inhibitor and TGF-β1- and PTEN-specific siRNAs were transfected into EA.hy926 cells to inhibit miR-663, TGF-β1, and PTEN expression, respectively. A wound healing assay was performed to determine the migratory ability of EA.hy926 cells.

RESULTS

miR-663 had higher expression levels in HUA-stimulated endothelial cells and in the sera of hyperuricemic patients and animals. TGF-β1 was targeted directly by miR-663. Endothelial miR-663 was up-regulated under HUA conditions, and HUA inhibited endothelial cell migration via miR-663, which targeted TGF-β1. Thus, TGF-β1 regulated cell migration in a PTEN-dependent manner.

CONCLUSION

HUA inhibits endothelial cell migration via miR-663, which regulates PTEN by targeting TGF-β1.

High concentrations of uric acid inhibit angiogenesis via regulation of the Krüppel-like factor 2-vascular endothelial growth factor-A axis by miR-92a

BACKGROUND

Angiogenesis is a critical component of many pathological conditions, and microRNAs (miRNAs) are indispensable in angiogenesis. It is unclear whether miRNAs regulate angiogenesis in the presence of high concentrations of uric acid (HUA), and the underlying mechanisms remain unknown.

METHODS AND RESULTS

It was found that HUA inhibited the angiogenic ability of endothelial cells. miRNA expression profiling was conducted using microarray assays in HUA-stimulated endothelial cells. Eighteen differentially expressed miRNAs were subjected to bioinformatic analyses. The results indicated that miR-92a was negatively regulated and was closely related to angiogenesis. Furthermore, the effects of miR-92a on HUA-stimulated endothelial cell angiogenesis and the underlying mechanisms were investigated in dual-luciferase reporter assays, electrophoretic mobility shift assays, immunoblot assays, and tube formation assays. It was determined that Krüppel-like factor 2 (KLF2) is a target gene of miR-92a, and KLF2 binds the vascular endothelial growth factor-A (VEGFA) promoter to inhibit its expression. miR-92a and VEGFA overexpression or KLF2 downregulation alleviates the HUA-mediated inhibition of angiogenesis in endothelial cells in vitro.

CONCLUSIONS

This study reported that there is a novel pathway regulating angiogenesis under HUA conditions. In the presence of HUA, miR-92a downregulation increased KLF2 expression, subsequently inhibiting VEGFA, which resulted in decreased angiogenesis. Thus, this study reports a possible mechanism for cardiovascular injury caused by hyperuricemia and suggests that the miR-92a-KLF2-VEGFA axis may be a target for hyperuricemia treatment.