A method for analysing tissue motion and deformation during mammalian organogenesis
Fig 5
Creating an in-silico fate map to analyse heart tube morphogenesis at both cellular and regional levels.
(A), Concatenation path of the individual live image. We concatenated through the hookPC and eye-PC strategy the videos related to embryos e31, e16, e35, e27, e24 and e12. The reference embryo is e35. (B), In-silico fate map tracking early cardiac morphogenesis as a continuum. The tool in Imaris allows to select points or regions in the myocardium and follow their motion over time from Gr2 to Gr9 in Atlas. In grey the point-cloud, in yellow the selected points track the regional changes at different stages. The lines, on the other hand, draw the displacement of the point-cloud. (C), The selected 10 arbitrary zones of the myocardium on the Gr9 shape. (C’), The displacement of the 10 zones in the different groups of the Dynamic Atlas. The two rows above represent the anterior part of the heart, the two rows below the posterior part. (D), Strategy to identify the same 10 anatomical zones in the live embryo. For each group, ‘Live-Shape’s were rescaled with a rigid registration algorithm to the Corresponding Atlas shape. Then the area of each mesh was calculated (colour map) for each rescaled ‘Live-Shape’s. Finally, the area values were averaged within the Atlas reference and summed for each of the 10 areas. (E-E’), The ‘Live-Shape’ and the Dynamic Atlas growth profiles of the 10 zones, interpolated for each Grs with a 3degree B-Spline. (E”) The validation strategy. (F) Top: A selected region in the Dynamic Atlas, illustrating how the region deformed anisotropically over time. Bottom: Cumulative anisotropy from Gr3 to Gr9. (G), At the cellular level (left), we tracked cell positions in e02 at Gr3 and Gr4 using Imaris (pink spots). On the right, we marked the initial positions of these cells on the fate map at Gr3 and then evaluated their predicted final positions at Gr4 (pink spots). (G’), At the regional level, we tracked different groups of points on the myocardium mesh of e27 from Gr4 to Gr5 (pink and yellow points). On the right, we identified the same groups of points on the fate map at Gr4 and assessed where these points ended up in Gr5. (H), Cellular-level error across 40 tracked cells from e01, e02, e05, and e16, compared to the corresponding predicted positions from the dynamic atlas. On average, the error is 20 µm, roughly equivalent to a cell diameter. Only 2 cells show an error greater than twice the cell diameter. We consider 95% of the cells to be well-predicted.