Cellular tissues acquire their function and shape via differentiation and morphogenesis, which molecular signaling pathways are known. However, how multicellular forces are organized during these processes remains to be explored. Here we show that topological defects featured in nematic assemblies of elongated cells organize multi cellular stresses. By confining myoblasts into circular micropatterns, we forced the formation of topological defects with integer charge, namely, spirals and asters. Using theory and deformable pillars, we probed the stresses generated at the core of these defects. We further show how topological defects localize tissue differentiation and promote the growth of cylindrical cellular protrusions by harnessing active stresses. We envision topological defects as mechanical organisation centres for controlling morphogenesis during development.

 

Zoom link: https://bristol-ac-uk.zoom.us/j/94983629930