Mechanical coupling narrows an epithelial colony before it reaches a bottleneck

MDCK epithelial monolayers migrating through a microchannel taper narrow their lateral extent and reorganize at the transition zone, with axial flow reversing sign repeatedly before entering the narrow inlet.

• Why it matters: Crowding in constrictions can jam non-living particles because contact interactions cannot reorganize before the bottleneck; it was unclear whether cohesive living tissue can adapt upstream.
• What they did: The team imaged migrating MDCK monolayers in microchannels that widen then narrow, used particle image velocimetry and nuclear tracking to quantify aperiodic axial velocity sign changes and positive divergence in the transition zone, and mapped edge belts via fluorescence and laser ablation.
• The result: A belt co-enriched in E-cadherin, F-actin, and myosin-II forms at the edges under elevated tension that dissolves after passing into the narrow inlet; E-cadherin knockdown abolishes narrowing, flow reversal, density redistribution, and belt assembly.

AI summary of the abstract · may contain errors · not medical advice · read the paper.