Single-cell imaging and transcriptomic analyses of endogenous cardiomyocyte dedifferentiation and cycling

a Cardiomyocyte renewal can potentially originate from pre-existing cardiomyocytes (GFP+) or resident progenitors (RFP+) in tamoxifen-treated bi-transgenic αMHC-MCM;RFPfl/GFP mice. b α-sarcomeric actinin (αSA, magenta) immunostaining on myocytes isolated from bi-transgenic αMHC-MCM;RFPfl/GFP mice with tamoxifen (TAM) or vehicle (VEH) treatment, or cells from wild-type (WT) littermates. Scale bar？=？50？μm. c Flow cytometry analysis showing the expression of GFP and RFP in myocytes isolated from hearts of bi-transgenic mice without (VEH) or with tamoxifen (TAM) treatment. The far-left panel shows the total ventricular populations containing small cells (non-myocytes), and larger cells (circled) that were either RFP+ (VEH; 2nd dot plot) or GFP+ (TAM; 3rd dot plot). n？=？3 mice for each group. d Expression profile of GFP and RFP in cardiomyocytes from bi-transgenic mouse ventricles 10 days, 3.5 weeks, or 3 months after MI or Sham operation. Statistics: p？>？0.05 in two-way ANOVA analysis (n？=？3–4 mice for each group). e ImageStream analysis on total ventricle cells from 3.5-week post-MI or sham mice. GFP and RFP are shown in channel Ch02 and Ch04, respectively; and BrdU incorporation signal revealed by Alexa Fluor 647-conjugated antibody is shown in Ch05; nuclear staining (by DAPI) in Ch01; and the bright phase signal in Ch03. n？=？3 mice (Sham or MI). *p？<？0.05 in t-tes