A, The experimental design for investigating adult CM reprogramming in vivo.
B, RNA expression level and induction level of OSKM in adult CMs after inducing OSKM reprogramming for 2 days. C, Protein expression level and induction level of OSKM in adult CMs after inducing OSKM reprogramming for 2 days. D, Flow cytometry analysis of isolated proliferative CMs through BrdU tracking in CM-reprogramming mice after OSKM induction. E, Percentage of proliferative CMs at each CM-reprogramming day determined by flow cytometry. F, Heart function measured by echocardiography in control or CM-reprogramming hearts after doxycycline treatment for 2 days. G, TUNEL staining of heart sections isolated from CM-OSKM mice after doxycycline treatment at the different time points. H, Heart function measured by echocardiography in control or CM-reprogramming hearts after doxycycline treatment for 5 days. I, Schematic diagram of intravital imaging protocol used for live investigating CM-reprogramming hearts after PBS or OSKM induction in vivo for 2 days. J, Investigation of CM alignment in the whole CM-reprogramming hearts by intravital microscopy after PBS or OSKM induction in vivo for 2 days. K, The morphology of CMs in CM-reprogramming hearts determined by length and width in intravital imaging data after PBS or OSKM induction in vivo for 2 days. Each dot represents one CM in one Ctrl or reprogramming heart. L, Aspect ratio determined by length-to-width ratio of each CM-reprogramming mouse in intravital imaging data after PBS or OSKM induction specifically in CMs in vivo for 2 days. Each dot represents one mouse sample. M, Immunofluorescence staining of heart tissue sections showing morphology of proliferative CMs through H3P and WGA staining on CM-reprogramming hearts after PBS or OSKM induction for 2 days. Arrow heads represented H3P+ proliferative CMs. Scale bars were 50 μm. N, Percentage of proliferative CM percentage (H3P+ %) in the heart tissue sections of CM-reprogramming hearts after PBS or OSKM induction for 2 days. O, The morphology of H3P+ CMs in three CM-reprogramming hearts determined by length, width, and aspect ratio in heart tissue sections after OSKM induction in vivo for 2 days. Each dot represents one CM in one Ctrl or reprogramming heart. P, The experimental design for discovering the detail mechanism for adult CM reprogramming at day 2 by microarray analysis. Q, Gene ontology analysis of gene expressional changes in adult CMs after PBS or OSKM induction for 2 days in vivo. R, Heat map showing metabolism-related gene expressional changes in adult CMs after PBS or OSKM induction for 2 days in vivo.