Figure 1.

Collective morphological response of population cells in ICM upon periodic TNF-α stimulation

(A) Schematic showing that the ICM was maintained in a microfluidic culture chamber and stimulated by dynamic TNF-α inflammatory signal of various amplitudes and frequencies.

(B) Cell-cell interactions are evaluated by measuring the triangular area connecting three neighboring cells.

(C–E) Relative displacement of the nucleus with respect to the neighbors causes changes in the triangular area, which reflect the cell-cell and cell-ECM interactions. The traces were normalized by their average value. The translucent lines are traces of individual cells. The solid line is the average of all traces, and the dashed line is the enlarged view of the solid line for better visualization of the fluctuation.

(F) Fast Fourier transform (FFT) shows that variations in the triangular area at all TNF-α input periodicities share a similar dominant frequency, ranging from 1/40 to 1/30 min⁻¹

(G–I) Collective vibration of nuclear centroid during cell migration within the ICM reflects deformation of the cell monolayer, which coordinates with periodic TNF-α stimulation. The traces were normalized by their average value. The translucent lines are traces of individual cells. The solid line is the average of all traces, and the dashed line is the enlarged view of the solid line for better visualization of the fluctuation.

(J) Fast Fourier transform (FFT) shows that the dynamic ICM deformation synchronizes with TNF-α input.

(K–M) Nuclear shape fluctuation (NSF) traces of single fibroblasts in the ICM upon stimulation. The traces were normalized by their average value. The translucent lines are traces of individual cells. The solid line is the average of all traces, and the dashed line is the enlarged view of the solid line for better visualization of the fluctuation.

(N) Fast Fourier transform (FFT) shows dominant NSF frequency between 1/20 and 1/30 min⁻¹, when stimulated by 1/20 min⁻¹ TNF-α stimulation.

(O) Fluctuation amplitude of nuclear shape changes in ICM and the stand-alone (SA) cells upon periodic TNF-α stimulation. The fluctuation amplitude of individual cells' nucleus was normalized to its time averaged area. The error bars represent standard deviation of population cell's fluctuation amplitude in nuclear area.

(P) Cross-correlation analysis of the morphological responses of population cells in the ICM reveals that the collective behavior is most obvious in NSF when stimulated by 1/20 min⁻¹ TNF-α input. The error bars represent standard deviation of the correlation coefficients between any 2 neighboring cells in a population.

(Q) Cross-correlation analysis between the morphological responses of population cells in the ICM and TNF-α periodic stimulations reveal that contractile activities of ICM as a whole entity coordinate with TNF-α stimulation. The error bars represent standard deviation of the correlation coefficients between individual cells and the TNF-α input.