Substrate Rigidity Modulates Segmentation Clock Dynamics in Isolated Presomitic Mesoderm Cells.

Area of Science:

• Developmental Biology
• Mechanobiology
• Cellular Oscillations

Background:

• The segmentation clock, a genetic oscillator in the presomitic mesoderm (PSM), is crucial for embryonic development.
• While biochemical signals are known regulators, the role of mechanical cues in segmentation clock function is poorly understood.
• The intricate PSM microenvironment complicates isolating mechanical effects on clock oscillations.

Purpose of the Study:

• To investigate the impact of mechanical stimuli on segmentation clock oscillations.
• To determine how substrate rigidity influences the behavior of PSM cells and their clock.
• To elucidate the role of cell-substrate interactions in somitogenesis.

Main Methods:

• Zebrafish PSM cells were cultured on polydimethylsiloxane (PDMS) micropost arrays with varying rigidities (0.6–1200 kPa).
• Oscillations, cell percentage, cycle counts, and periods were quantified.
• Cellular biophysical properties including motility, contractility, and circularity were analyzed.

Main Results:

• An inverse sigmoidal relationship was observed between substrate rigidity and the percentage of oscillating cells and oscillation cycles.
• A switching threshold for oscillation was identified between 3–6 kPa rigidity.
• Cellular properties such as motility, contractility, and circularity were altered by substrate rigidity.

Conclusions:

• Cell-substrate interactions play a critical role in regulating segmentation clock behavior.
• Mechanical cues significantly influence the oscillatory dynamics of the segmentation clock.
• These findings provide insights into the mechanobiology of somitogenesis and embryonic patterning.