(A) Male ApoE−/− mice fed a Western Diet (WD) for 17 weeks followed by treatment of S2PNP-siCtrl or S2PNP-siEpsin1/2 for 3 weeks (2 doses per week). (B) En face ORO staining of aortas from baseline, control siRNA NP-treated ApoE−/− or Epsin1/2 siRNA NP treated male ApoE−/− mice fed a WD, lesion areas were analyzed with NIH ImageJ, scale bar=5mm. (C) ORO staining of brachiocephalic artery (BCA) and aortic root sections of above three groups. Lesional area (black dash line outlined) were analyzed by NIH ImageJ. (D) Aortic roots from S2PNP-siCtrl-treated ApoE−/− or S2PNP-siEpsin1/2 treated male ApoE−/− mice were stained with the macrophage marker CD68 (dashed white line outlined) and αSMA (white arrow). (E) H&E staining of BCA and aortic root sections of the above three groups. Necrotic areas (black dash line outlined) were analyzed by NIH ImageJ. Data from B-E (n=6) are presented as mean ± SD. Scale bar: B=5mm; C, D, E=500μm. One-way ANOVA followed by Tukey’s post hoc multiple comparisons test was conducted in B-E.