Fig. 2.

A single SMC gives rise to most of the cells in an atherosclerotic plaque. a, b ApoE^(−/−), SMMHC-CreER^T2, ROSA26R^(Rb/+) mice were induced with tamoxifen (1 mg/day for 5 days), rested, fed a high fat diet (HFD) for 6 or 12 weeks as indicated, and transverse aortic root sections were stained with DAPI and directly imaged for the Rb colors (mCherry (mCh), mOrange (mOr), and Cerulean (Cer)). Marked cells in each atherosclerotic plaque are a single color (Cer in a and mOr in b) indicating that a single SMC gives rise to all smooth muscle-derived plaque cells. Scale bars, 50 μm. c Quantification of marked cells by Rb color in aortic root atherosclerotic plaques and adjacent media mice fed a high fat diet for 6, 12, and 16 weeks from sections stained and imaged as in a and b. n = 9 mice (all male), 11 atherosclerotic plaques, 6 sections per plaque were quantified and the average number of labeled plaque cells scored per plaque by duration of high fat diet: 6 weeks (80 plaque cells), 12 weeks (458), and 16 weeks (936). d Quantification of the average percent of atherosclerotic plaque cells that are SMC-derived classified by weeks of high fat feeding. n = 9 mice, 11 plaques. *vs. 6 weeks, p < 0.0001. One-way ANOVA with Tukey’s multiple comparisons test was used. Error bars represent standard deviations