High Glucose/Thrombin-Induced Endothelial Inflammation Via Microrna-146a and Nox4 Regulation

Diabetes is associated with hyperglycemia and increased thrombin generation. It is unknown whether high glucose (HG)/thrombin can modulate the expression of NAPDH oxidase (Nox) subtypes in human aortic endothelial cells (HAECs). Besides, we investigate whether miR-146a is involved in endothelial cell inflammation. We observed that HG (25 mmol/l) exerted a synergistic effect with thrombin (2 U/ml) for induction of Nox4 mRNA level in HAECs. The increased Nox4 mRNA was associated with increased Nox4 protein and ROS production. We also demonstrated that HG/thrombin treatment increased interleukin-8 and interleukin-6 protein levels. Besides, HG/thrombin treatment caused an 11.43-fold increase of THP-1 adhesion to HAECs. In Silico analysis identified homology between miR-146a and the 3’-UTR of the human Nox4 mRNA, suggesting a potential regulation of Nox4 by miR-146a. Furthermore, HG/thrombin treatment decreased miR146a expression to 58% of the control, indicating an impaired feedback restrain of HG/thrombin-induced endothelial inflammation. MiR-146a mimic transfection prevented HG/thrombin-induced upregulation of Nox4 mRNA, Nox4 protein, and ROS generation. In addition, inflammatory phenotypes were attenuated in miR-146a mimic-transfected HAECs. In conclusion, miR-146a is involved in the regulation of endothelial inflammation via modulation of Nox4 in an in-vitro milieu mimicking diabetic atherothrombosis.