Spatio-Temporal Growth Patterns at Cell and Tissue Levels in the C-Looping Heart

Heart development consists of a series of sequential events including looping. Successful looping is vital to normal development of the heart, and aberrant looping leads to various congenital heart diseases. Looping is a very complex process and, despite a great deal of experimental data and research, the underlying mechanisms controlling the looping phase are unclear. A number of hypotheses have been proposed to explain the looping process, but none of them has yet been fully accepted or rejected. In this study, a comprehensive workflow is developed to investigate C-looping (the first phase of the looping process) using multi-scale and multi-disciplinary experimental and computational approaches. Our results, in general, support the differential growth hypothesis of C-looping by providing further qualitative and quantitative evidence with high spatial and temporal resolution, but also give insights into new cellular features regarding the mechanism of C-looping. We reveal the differential spatio-temporal patterns of growth at both the cellular and tissue levels, and show how geometrical changes of C-looping at the tissue level are linked to growth features at the cellular level. Furthermore, we provide the first 3D datasets for the C-looping heart with cell to organism level information, including datasets of heart images and segmented myocardial cells within the heart.