Simulating the mammalian blastocyst--molecular and mechanical interactions pattern the embryo

Area of Science:

• Developmental Biology
• Computational Biology
• Cell Mechanics

Background:

• Mammalian embryogenesis involves complex gene expression and mechanical forces.
• Precise lineage patterning of trophectoderm and endoderm is crucial but debated.
• Understanding these interactions is key to embryonic development.

Purpose of the Study:

• To develop a computational framework analyzing combined mechanical and genetic interactions in proliferating cells during mammalian embryogenesis.
• To quantitatively compare hypotheses on position-dependent vs. gene expression-dependent cell fate in trophectoderm formation.
• To investigate mechanisms of endoderm formation, including differential adhesion and blastocoel dynamics.

Main Methods:

• Developed a computational modeling framework integrating cell-based spatial mechanical simulations with genetic networks.
• Analyzed mechanical forces, elastic conformational energy, and cell-cell adhesion.
• Simulated gene expression and its interplay with cell movement and positioning.

Main Results:

• Demonstrated mechanical forces minimize elastic energy, aligning embryonic axes (a-v and eb-ab) within the zona pellucida.
• Showed coupling of gene expression and cell mechanics is vital for trophectoderm and endoderm formation.
• Identified differential adhesion as critical for robust endoderm formation, with two distinct hypotheses proposed for its mechanism.

Conclusions:

• The computational framework provides a novel approach to test hypotheses in silico.
• Mechanical forces and gene expression are intricately linked in mammalian embryogenesis.
• Differential adhesion and blastocoel dynamics are critical factors in endoderm development.