Presentation Information
[POS-08]Surface tension driven phase-field model of Dictyostelium fruiting body formation
*Seiya Nishikawa1, Satoshi Kuwana2, Gen Honda2, Hidenori Hashimura2, Satoshi Sawai2, Shuji Ishihara2 (1. Kyoto Univ. (Japan), 2. The Univ. of Tokyo (Japan))
Keywords:
Phase-field model,Quantitative analysis,Dictyostelium discoideum,Fruiting body,Morphogenesis
In multicellular organisms, cell populations exhibit highly self-organized behavior during development, wound healing, and other processes. For orchestrated multicellular behaviors, not only biochemical but also mechanical properties of cells are important. Fruiting body formation in Dictyostelium discoideum is an excellent model system for understanding such mechanically driven cell behavior, in which the formation of complex 3D tissues, known as culmination, can be directly observed. Here we applied two theoretical approaches to the culmination process for understanding this complex tissue development.
First, using the morphology and mechanical parameters (e.g., Young’s modulus) measured in our experiments, we characterized several mechanical aspects of fruiting bodies, such as the bending elasticity of the stalk, the magnitude of gravitational effects, and the force balance between internal pressure and surface tension in the tissue.
Since the above analysis suggested the importance of surface tension, we constructed a phase-field-based continuum model in which surface tension acts as the driving force for tissue deformation. By introducing phase fields φ and ρ and velocity fields v, the model successfully reproduces the culmination. We subdivided the tissue formation process into early and late stages, and quantitatively compared experimental observations with simulation results at each stage from a morphological perspective. In the experimental analysis of the early stage, we found that the relationship between the ratio of the tissue’s base radius to its height and the contact angle between the tissue and the substrate, showed the same trend. The simulation also exhibited the same trend, indicating that tissue surface tension determines the saturation value of the contact angle. In the analysis of the late stage, we found that the epithelial-like properties of the upper region are crucial for reproducing the observed morphology. In addition, we examined the effect of surface tension acting on each tissue surface using our mathematical model. In the future, the application of our surface tension driven phase-field model is expected to further advance our understanding of the physical aspects of 3D tissue morphogenesis.
First, using the morphology and mechanical parameters (e.g., Young’s modulus) measured in our experiments, we characterized several mechanical aspects of fruiting bodies, such as the bending elasticity of the stalk, the magnitude of gravitational effects, and the force balance between internal pressure and surface tension in the tissue.
Since the above analysis suggested the importance of surface tension, we constructed a phase-field-based continuum model in which surface tension acts as the driving force for tissue deformation. By introducing phase fields φ and ρ and velocity fields v, the model successfully reproduces the culmination. We subdivided the tissue formation process into early and late stages, and quantitatively compared experimental observations with simulation results at each stage from a morphological perspective. In the experimental analysis of the early stage, we found that the relationship between the ratio of the tissue’s base radius to its height and the contact angle between the tissue and the substrate, showed the same trend. The simulation also exhibited the same trend, indicating that tissue surface tension determines the saturation value of the contact angle. In the analysis of the late stage, we found that the epithelial-like properties of the upper region are crucial for reproducing the observed morphology. In addition, we examined the effect of surface tension acting on each tissue surface using our mathematical model. In the future, the application of our surface tension driven phase-field model is expected to further advance our understanding of the physical aspects of 3D tissue morphogenesis.