Sarcomere function activates a p53-dependent DNA damage response that promotes polyploidization and limits in vivo cell engraftment

Cell Rep. 2021 May 4;35(5):109088. doi: 10.1016/j.celrep.2021.109088.


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.

Keywords: DNA damage; P53; cardiac regeneration; cardiomyocytes; cell cycle; cell therapy; polyploidization; sarcomere; single-cell genomics.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Proliferation
  • DNA Damage / genetics*
  • Disease Models, Animal
  • Humans
  • Rats
  • Sarcomeres / metabolism*
  • Tumor Suppressor Protein p53 / metabolism*


  • Tumor Suppressor Protein p53