Conference Agenda

Cell organisation controls critical physiological functions in a range of organs, but this organisation has never been thought to be influenced by tissue shape. We show that the overall shape of the tissue strongly affects the alignment of fibroblasts. For rectangular-shaped tissues, cells align preferentially with the long axis, with the degree of alignment increasing with both the tissue aspect ratio and cell density. Remarkably, this alignment occurs without corresponding realignment of the collagen. Moreover, there is no spatial gradient in cell distribution, consistent with the fact that self-similarly increasing tissue size did not affect cell alignment; all of this suggests a very long-range mechanism by which cells detect the overall tissue shape. We demonstrate that these counterintuitive observations can be rationalized by recognizing that, unlike a collection of non-living particles that collectively attain an equilibrium state, the internal metabolic processes within living cells drive them to maintain a homeostatic state individually. This individual constraint, combined with the overall constraint of the tissue, drives a long-range mechanism of tissue shape detection.