IPLS/BioP Seminar: Dr. Herve Turlier (Collège de France)

Abstract: Early embryos are shaped via a series of cell divisions, shape changes and rearrangements leading generally to a stereotypical blastula structure before gastrulation. I will summarize our recent analysis and modeling efforts to decipher the self-organizing principles of the mouse embryo morphogenesis, combining 3D numerical simulations with simple concepts of soft- matter physics. Pre-implantation mammalian embryogenesis leads to the blastocyst, a structure composed of an epithelial layer surrounding an inner mass of cells and a fluid-filled cavity. In a collaborative efforts with biologists, we demonstrated in the past years that differential changes in cell surface tensions are sufficient to drive the process of compaction at 8-cell stage and the formation of the inner-cell mass at the 8-to-16 cells transition. Here I will focus on the formation and positioning of the blastocoel cavity after the 32-cell stage. I will present our recent results demonstrating that the blastocoel forms by hydraulic fracturing of cell-cell contacts into hundreds of microlumens, which then coarsen into a single cavity though hydro-osmotic luminal fluid exchange.