A multiscale model of early cell lineage specification including cell division

Area of Science:

• Developmental Biology
• Computational Biology
• Systems Biology

Background:

• Embryonic development involves complex cell division, interaction, and fate changes governed by gene regulatory networks.
• The preimplantation mouse embryo's inner cell mass differentiates into epiblast and primitive endoderm, a process not fully understood.
• Understanding early cell fate acquisition is crucial for developmental biology and regenerative medicine.

Purpose of the Study:

• To model the dynamic process of epiblast and primitive endoderm cell fate acquisition in the mouse preimplantation embryo.
• To investigate the robustness of existing models of cell fate selection within a realistic 3D framework.
• To elucidate the interplay between gene regulatory networks and extracellular signaling in early embryonic patterning.

Main Methods:

• Developed a multiscale computational model incorporating cell division, cell-cell interactions, and intracellular/extracellular biochemical reactions.
• Simulated the acquisition of epiblast and primitive endoderm identities within the inner cell mass.
• Analyzed the role of noise and extracellular signaling (Fgf4) in breaking symmetry and driving cell fate specification.

Main Results:

• Confirmed the robustness of extracellular signaling mechanisms in driving cell fate selection via a tristable regulatory network.
• Simulations recapitulated in vivo observations in wild-type and mutant mouse embryos.
• Demonstrated that gene regulatory networks confer differential plasticity to cell fates.
• Highlighted the critical role of noise and Fgf4 signaling in generating initial cell heterogeneity and driving salt-and-pepper patterning.

Conclusions:

• The interplay between internal gene regulatory networks and extracellular Fgf4 signaling drives developmental transitions and cell patterning.
• Initial cell-to-cell differences, amplified by self-regulation, are essential for establishing distinct cell fates by the blastocyst stage.
• Noise is a necessary component for initiating the cell specification process in early embryonic development.