MiRNA profiling in aortas of Apoe-/- mice with an specific knock-out of Dicer in endothelial cells compared to control mice after 12 weeks of a high-fat diet

Increased monocyte adhesion to dysfunctional endothelial cells (ECs) orchestrated by chemokines plays an important role in arterial inflammation during atherosclerosis. Endothelial microRNAs (miRNAs) processed by the RNase Dicer1 determine the phenotype of ECs by posttranscriptional regulation of gene expression. However, the impact of endothelial miRNAs on endothelial inflammation and atherosclerosis is currently unclear. To study the effect of Dicer-dependent miRNAs in ECs on atherosclerosis, Apoe-/- mice with an inducible, EC-specific knock-out of Dicer (EC-Dicerflox) and control mice (EC-DicerWT) mice were treated with tamoxifen to induce Cre-recombinase activity and fed with a high fat-diet (HFD) for 12 weeks. The comparison of the miRNA expression profile in the aortas of EC-Dicerflox and EC-DicerWT mice after 12 weeks of a HFD was performed to identify EC-specific miRNAs that may play a role in the EC function during atherogenesis. VE-Cadherin-CreERT2 mice were crossed with Dicer1flox/flox/Apoe-/- to obtain VE-Cadherin-CreERT2Dicer1WT/flox/Apoe-/-. VE-Cadherin-CreERT2Dicer1flox/flox/Apoe-/- (EC-Dicerflox) mice and VE-Cadherin-CreERT2Dicer1WT/WT/Apoe-/- (EC-DicerWT) littermates were used for experiments. Cre-recombinase activity was induced by Tamoxifen (TMX) treatment (2 mg/20 g body weight, dissolved in neutral oil) for 5 consecutive days (i.p. injection). One week after the last TMX injection, 6-8 week old females were fed a high-fat diet (HFD) comprising 21% crude fat, 0.15% cholesterol and 19.5% casein for 12 weeks. The aortas were harvested after in situ perfusion with RNAlater and total RNA was isolated using mirVana microRNA Isolation Kit. The Dicer knockout in EC-Dicerflox mice was confirmed by quantification of Dicer1 mRNA expression in the aortas of EC-DicerWT and EC-Dicerflox by qRT-PCR.