Inhibition of Aberrant MicroRNA-133a Expression in Endothelial Cells by Statin Prevents Endothelial Dysfunction by Targeting GTP Cyclohydrolase 1 in vivo
Background —GTP cyclohydrolase 1 (GCH1) deficiency is critical for endothelial nitric oxide synthase (eNOS) uncoupling in endothelial dysfunction. MicroRNAs (miR) are a class of regulatory RNAs that negatively regulate gene expression. We investigated whether statins prevent endothelial dysfunction via miR-dependent GCH1 upregulation.
Methods —Endothelial function was assessed by measuring acetylcholine- induced vasorelaxation in the organ chamber. MiR-133a expression was assessed by RT-qPCR and fluorescence in situ hybridization.
Results — We first demonstrated that GCH1 mRNA is a target of miR-133a. In endothelial cells, miR-133a was robustly induced by cytokines/oxidants and inhibited by lovastatin. Furthermore, lovastatin upregulated GCH1 and tetrahydrobiopterin (BH4), and recoupled eNOS in stressed endothelial cells. These actions of lovastatin were abolished by enforced miR-133a expression and were mirrored by a miR-133a antagomir. In mice, hyperlipidemia or hyperglycemia induced ectopic miR-133a expression in the vascular endothelium, reduced GCH1 protein and BH4 levels, and impaired endothelial function, which were reversed by lovastatin or miR-133a antagomir. These beneficial effects of lovastatin in mice were abrogated by in vivo miR-133a overexpression or GCH1 knockdown. In rats, multiple cardiovascular risk factors including hyperglycemia, dyslipidemia, and hyperhomocysteinemia resulted in increased miR-133a vascular expression, reduced GCH1 expression, uncoupled eNOS function, and induced endothelial dysfunction, which were prevented by lovastatin.
Conclusions —Statin inhibits aberrant miR-133a expression in the vascular endothelium to prevent endothelial dysfunction by targeting GCH1. Therefore, miR-133a represents an important therapeutic target for preventing cardiovascular diseases.
- Received April 12, 2016.
- Revision received September 1, 2016.
- Accepted September 20, 2016.
Circulation is published on behalf of the American Heart Association, Inc., by Wolters Kluwer. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial License (http://creative commons.org/licenses/by-nc/3.0/), which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited and is not used for commercial purposes.