Branching geometry induced by lung self-regulated growth

Area of Science:

• Developmental Biology
• Computational Biology
• Morphogenesis

Background:

• Branching morphogenesis is crucial for organogenesis, exemplified by mammalian lung development.
• Key signaling molecules like Fibroblast Growth Factor 10 (FGF10) and Sonic Hedgehog (SHH) regulate lung branching.
• Previous models demonstrated FGF10 dynamics can induce self-avoiding branching, but early lung geometry features remained unexplained.

Purpose of the Study:

• To investigate if the FGF10-diffusion model can account for specific early lung morphology aspects.
• To analyze the emergence of size dispersion, branching asymmetry, and epithelium-mesothelium equilibrium.
• To understand the underlying mechanisms driving these geometrical features through simulations and data analysis.

Main Methods:

• Utilized a Laplacian model to simulate FGF10 dynamics in the mesenchyme.
• Performed data analysis alongside simulations to examine lung morphology.
• Focused on understanding how gradient-mesenchyme interactions and shape influence branching patterns.

Main Results:

• The FGF10-diffusion model spontaneously generated size dispersion in lung structures.
• Asymmetry in branching events emerged naturally within the simulation.
• The model successfully reproduced the distal epithelium-mesothelium equilibrium.
• These features were linked to dynamical interactions between FGF10 gradients and tissue shape.

Conclusions:

• The FGF10-diffusion model adequately explains complex early lung geometry, including size dispersion and asymmetry.
• Emergence of these features is driven by intrinsic interactions between signaling gradients and tissue shape.
• Specific regulatory mechanisms may not be essential for generating these striking geometrical aspects of lung development.