Extended Data Fig. 2. SMC investment is significantly impaired in the aortic root of Pdgfrb^SMC-Δ/Δ mice and SMC-PDGFRB KO did not show reduced dedifferentiation, proliferation, or apoptosis of medial SMC following 18 weeks of WD.

(A) Representative images of aortic root lesions from Pdgfrb^SMC-WT/WT and (B) Pdgfrb^SMC-Δ/Δ mice. (C) Quantification of Myh11-eYFP⁺ cells content in the fibrous caps of aortic root lesions from Pdgfrb^SMC-WT/WT and Pdgfrb^SMC-Δ/Δ mice, demonstrated a significant reduction in SMC-derived cells in aortic root lesions. ***p-value = 0.0002. (D) Representative image of the media from the BCA of Pdgfrb^SMC-WT/WT and Pdgfrb^SMC-Δ/Δ mice show ACTA2 downregulation in the innermost layer of the media. (E) Quantification of Myh11-eYFP⁺ACTA2⁺ cells in the media. (F) Representative image of Ki67 staining in Myh11-eYFP⁺ SMC in the media. (G) Quantification of Ki67 expression in the media, representing proliferation. Ki67⁺: **p-value = 0.0017, Myh11-eYFP⁺ Ki67⁺ *p-value = 0.0130, Myh11-eYFP⁻ Ki67⁺ *p-value = 0.0337. (H) Representative image of cleaved caspase 3 staining in Myh11-eYFP⁺ SMC in the media. Myh11-eYFP⁻ Casp3⁺ p-value = 0.0476. (I) Quantification of Casp3 expression in the media, representing apoptosis. *p-value = 0.0476. A: Adventitia, M: Media, L: Lesion. Scale bar: 100μm (whole lesion) or 20μm (zoom). Graphs were analyzed using Graphs were analyzed using two-way ANOVA with Sidak correction and multiple comparisons or two-tailed Mann-Whitney U test, biologically independent animals are indicated as individual dots in (C, H, I), n = 8 (WT and KO) in (G), error bars represent mean ± SEM.