Inhibition of microRNA-92a Prevents Endothelial Dysfunction and Atherosclerosis in Mice
Rationale: MicroRNAs (miRNAs) are small non-coding RNAs that regulate protein expression at post-transcriptional level. We hypothesized that a specific pool of endothelial miRNAs could be selectively regulated by flow conditions and inflammatory signals, and as such be involved in the development of atherosclerosis.
Objective: To identify miRNAs, called atheromiRs, that are selectively regulated by shear stress and oxidized low-density lipoproteins (oxLDL), and determine their role in atherogenesis.
Methods and Results: Large scale miRNA profiling in HUVECs identified miR-92a as an atheromiR candidate, whose expression is preferentially upregulated by the combination of low shear stress (SS) and atherogenic oxLDL. Ex vivo analysis of atheroprone and atheroprotected areas of mouse arteries and human atherosclerotic plaques demonstrated the preferential expression of miR-92a in atheroprone low SS regions. In Ldlr-/- mice, miR-92a expression was markedly enhanced by hypercholesterolemia, in particular in atheroprone areas of the aorta. Assessment of endothelial inflammation in gain- and loss-of-function experiments targeting miR-92a expression revealed that miR-92a regulated endothelial cell activation by oxLDL, more specifically under low SS conditions, which was associated with modulation of KLF2, KLF4 and SOCS5. miR-92a expression was regulated by STAT3 in SS- and oxLDL-dependent manner. Furthermore, specific in vivo blockade of miR-92a expression in Ldlr-/- mice reduced endothelial inflammation and altered the development of atherosclerosis, decreasing plaque size and promoting a more stable lesion phenotype.
Conclusions: Upregulation of miR-92a by oxLDL in atheroprone areas promotes endothelial activation and the development of atherosclerotic lesions. Therefore, miR-92a antagomir appears as a new athero-protective therapeutic strategy.
- Received July 17, 2013.
- Revision received November 15, 2013.
- Accepted November 19, 2013.