Nematic cell alignment directs calcium waves in an epithelial monolayer

Area of Science:

• Cell biology
• Biophysics
• Developmental biology

Background:

• Tissues coordinate cells using long-range supracellular signals like calcium waves and cell alignment (nematic order).
• Calcium waves guide cell migration during wound healing, while nematic order defects can localize morphogenetic events.
• These signals have typically been studied independently.

Purpose of the Study:

• To investigate the relationship between long-range calcium signaling and cell nematic order in epithelial tissues.
• To understand how cell alignment affects the dynamics of wound-induced calcium waves.
• To model the impact of orientation defects on information propagation within tissues.

Main Methods:

• Experimental measurement of calcium wave dynamics in epithelial tissues.
• Development of a reaction-diffusion model incorporating anisotropic diffusive coupling.
• Analysis of how cell orientation influences wave speed and front propagation.

Main Results:

• Calcium wave speed is dependent on the angle between the wave vector and cell axis, with maximal speed perpendicular to tissue orientation.
• A reaction-diffusion model with anisotropic coupling successfully recapitulates experimental calcium wave dynamics.
• Nematic defects cause anisotropic diffusivity, bending calcium wave fronts and desynchronizing signal reception.

Conclusions:

• Spatial patterns of cell alignment directly control collective communication via calcium signaling.
• Orientation defects can disrupt information propagation across tissues by altering calcium wave dynamics.
• This interplay is crucial for processes like development, wound healing, and disease progression.