Mechanics of cardiomyocyte nuclei in a beating heart

<p dir="ltr">How the nucleus, one of the stiffest organelles inside a cell, sustains and responds to mechanical forces in vivo remains understudied. The developing zebrafish vertebrate heart is a unique model system to address this fundamental problem as it generates and withstands substantial mechanical forces.</p><p dir="ltr">Using in toto imaging, 3D morphometrics, genetics, pharmacological perturbations and scRNA-seq, our work reveals that the two heart chambers, ventricle and atrium, have strikingly distinct cardiomyocyte nuclear morphologies, possibly correlating with Lamin A/C expression and microtubule localisation. Manipulation of cardiac forces and knockdown of Lamin A/C affects only ventricle nuclear morphology while microtubule manipulation affects nuclear morphology in both chambers. Of note, overexpressing Lamin A/C in atrium, which naturally lacks Lamin A/C expression leads to nuclear fragmentation. Together, these results indicate that the two chambers have distinct nuclear mechanics, possibly reflecting the underlying difference in the biomechanical environment.</p><p dir="ltr">Poster presented as part of the Crick BioImage Analysis Symposium 2024.</p><p dir="ltr"><i>Permission has been given by authors to upload to Crick Figshare. Copyright remains with the original authors.</i></p>