Mechanics of epithelial closure over non-adherent environments

Sri Ram Krishna Vedula (1) , Grégoire Peyret (2) , Ibrahim Cheddadi (3) , Tianchi Chen (1) , Agustí Brugués (4) , Hiroaki Hirata (1) , Horacio Lopez-Menendez (2) , Yusuke Toyama (1) , Luís Neves de Almeida (5, 6) , Xavier Trepat (7, 8, 4) , Chwee Teck Lim (1) , Benoit Ladoux

1 NUS - National University of Singapore
2 IJM (UMR_7592) - Institut Jacques Monod
3 VIRTUAL PLANTS - Modeling plant morphogenesis at different scales, from genes to phenotype
4 IBEC - Institute for Bioengineering of Catalonia [Barcelona]
5 LJLL - Laboratoire Jacques-Louis Lions
6 MAMBA - Modelling and Analysis for Medical and Biological Applications
7 ICREA - Institució Catalana de Recerca i Estudis Avançats = Catalan Institution for Research and Advanced Studies
8 CIBERES - Centro de Investigación Biomédica en Red Enfermedades Respiratorias

The closure of gaps within epithelia is crucial to maintain its integrity during biological processes such as wound healing and gastrulation. Depending on the distribution of extracellular matrix, gap closure occurs through assembly of multicellular actin-based contractile cables or protrusive activity of border cells into the gap. Here we show that the supracellular actomyosin contractility of cells near the gap edge exerts sufficient tension on the surrounding tissue to promote closure of non-adherent gaps. Using traction force microscopy, we observe that cell-generated forces on the substrate at the gap edge first point away from the centre of the gap and then increase in the radial direction pointing into the gap as closure proceeds. Combining with numerical simulations, we show that the increase in force relies less on localized purse-string contractility and more on large-scale remodelling of the suspended tissue around the gap. Our results provide a framework for understanding the assembly and the mechanics of cellular contractility at the tissue level.

Domains: Life Sciences [q-bio]; Environmental Engineering

Sri Ram Krishna Vedula, Grégoire Peyret, Ibrahim Cheddadi, Tianchi Chen, Agustí Brugués, et al.. Mechanics of epithelial closure over non-adherent environments. Nature Communications, 2015, 6, pp.Article number: 6111. ⟨10.1038/ncomms7111⟩. ⟨hal-01298859⟩