Mechanics of Embryonic Self-Organization and Plasticity – Embryonics
To measure the forces that shape the embryo and its mechanical properties (i.e. the properties that dictate the deformation of tissues in response to these forces), it is necessary to interact in a controlled manner and in real time with the developing embryo. We have therefore built a motorized micromanipulator that allows us to come in contact with the embryo while its development is monitored in real time by video-microscopy. The development of this micromanipulator required to adapt to the constraints related to the culture of the embryo but also to those related to its imaging. Moreover, we have set up an image analysis and biophysical modeling system allowing us to extract physical quantities from the films obtained during the experiments.
The development of this approach (micromanipulator and biophysical analysis) allowed us to measure in absolute values the forces, elasticity and viscosity of the early embryo and thus to approach the formation of the embryo from a biophysical point of view. Our results indicate that the embryo behaves as an elastic material over short times (seconds, minutes), and as a fluid material over long times (tens of minutes).
These results will allow us to explore the cellular events underlying the elasticity and viscosity of the tissue or to apply controlled mechanical perturbations and observe the effects on the development of the embryo. These are areas of research that we are currently pursuing.
This approach, experimental and conceptual, will allow both the mapping and perturbation of the mechanical forces and material properties of the different embryonic territories that make up the early embryo, paving the way to understanding how mechanical and molecular signals interact to allow the emergence of cell fate, during embryonic self-organization.
- One publication in progress.
- One review on the role of mechanical force in patterning has been published: P.-F. Lenne et al., Phys Biol. 18 (2021), doi:10.1088/1478-3975/abd0db
How molecular and mechanical cues combine to coordinate the morphogenesis and patterning of embryonic structures is an open question in the field of developmental biology. The early avian embryo is an ideal model for the study of this interplay as it exhibits highly regulative development, is greatly amenable to live imaging approaches, and can be readily mechanically challenged. We have recently characterized the mechanical forces that shape the early avian embryo, identifying a tensile ring, at the margin between the embryonic and extra-embryonic territories, as the driver of morphogenetic movements within the embryonic disk. These findings suggest that mechanical stresses transmitted along the embryo margin and throughout the surrounding tissue could function as signals in embryonic regulation and in the establishment of embryonic territories. To pursue this hypothesis, we propose, through a tight integration of experiments and theory, to i) test whether a mechanical self-organizing system underlies the remarkable regulative potential of the early avian embryo; ii) elucidate the role of mechanical forces in cell fate specification. These studies will decipher the interplay between cellular, molecular, and mechanical cues that ensures the robust, yet plastic, specification and allocation of cell fate.
Monsieur Jerome GROS (INSTITUT PASTEUR)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
LPENS Laboratoire de physique de l'ENS
IP INSTITUT PASTEUR
Help of the ANR 130,680 euros
Beginning and duration of the scientific project: March 2020 - 48 Months