Figure 3: NOTCH-Mediated Regulation of Cell Fate Decision Between the Smooth Muscle Cell and Cardiomyocyte Lineages Depends on

(A) Expression of MIR-143 and MIR-145 in proliferating CPCs (Expansion; black) and in adult CPCs exposed to DLL1 (gray), and differentiated in the absence (upper panels) or presence of DAPT (lower panels). Data represent mean ± SEM; *p < 0.05 as compared with proliferating CPCs; ‡p < 0.05 as compared with differentiating unstimulated (None; white) CPCs in absence of DAPT (n = 5). (B) Expression of MIR-143, -145, and miRNA targets (ELK1, KLF4) in proliferating CPCs (Expansion; black) and in differentiated adult CPCs (without prior DLL1 exposure, in the absence of DAPT). Cells were either transfected (white) or not (None; gray) with the indicated miRNA LNA inhibitor. Data represent mean ± SEM; *p < 0.05 as compared with proliferating CPCs; ‡p < 0.05 as compared with differentiating CPCs transfected with scrambled miRNA LNA inhibitor (n = 3). (C) Expression of sarcomeric proteins (MYH6, MYH7, MYH11) in proliferating CPCs (Expansion; black) and in differentiated adult CPCs (without prior DLL1 exposure, in the absence of DAPT). Cells were transfected (white) or not (None; gray) with the indicated miRNA LNA inhibitor. Data represent mean ± SEM; *p < 0.05 as compared with proliferating CPCs; ‡p < 0.05 as compared with differentiating CPCs transfected with scrambled miRNA LNA inhibitor (Scr) (n = 3). (D) Analysis of SM-MHC and α-ACTININ expression by immunostaining in differentiated CPCs (without prior DLL1 exposure, in the absence of DAPT), transfected or not with the indicated miRNA LNA inhibitor. Nuclei were stained with DAPI (blue). Scale bars: 50 μm. Quantification of the numbers of α-ACTININPOS cardiomyocytes or sm-MHCPOS smooth muscle cells. Data represent mean ± SEM; *p < 0.05 as compared with proliferating CPCs; ‡p < 0.05 as compared with differentiating CPCs transfected with scrambled miRNA LNA inhibitor (Scr) (minimum 2,000 cells in 30 different fields at a magnification of 40× per quantification). Abbreviations as in Figure 1.