Cell Rep 2021 May 4; 35(5):109088
Human cardiac regeneration is limited by low cardiomyocyte replicative rates and progressive polyploidization by unclear mechanisms. To study this process, we engineer a human cardiomyocyte model to track replication and polyploidization using fluorescently tagged cyclin B1 and cardiac troponin T. Using time-lapse imaging, in vitro cardiomyocyte replication patterns recapitulate the progressive mononuclear polyploidization and replicative arrest observed in vivo. Single-cell transcriptomics and chromatin state analyses reveal that polyploidization is preceded by sarcomere assembly, enhanced oxidative metabolism, a DNA damage response, and p53 activation. CRISPR knockout screening reveals p53 as a driver of cell-cycle arrest and polyploidization. Inhibiting sarcomere function, or scavenging ROS, inhibits cell-cycle arrest and polyploidization. Finally, we show that cardiomyocyte engraftment in infarcted rat hearts is enhanced 4-fold by the increased proliferation of troponin-knockout cardiomyocytes. Thus, the sarcomere inhibits cell division through a DNA damage response that can be targeted to improve cardiomyocyte replacement strategies.
Pettinato, Anthony M; Yoo, Dasom; VanOudenhove, Jennifer; Chen, Yu-Sheng; Cohn, Rachel; Ladha, Feria A; Yang, Xiulan; Thakar, Ketan; Romano, Robert; Legere, Nicolas; Meredith, Emily; Robson, Paul; Regnier, Michael; Cotney, Justin L; Murry, Charles E; and Hinson, J Travis, "Sarcomere function activates a p53-dependent DNA damage response that promotes polyploidization and limits in vivo cell engraftment." (2021). Faculty Research 2021. 95.