Mechanics of epithelial closure over non-adherent environments

• Published in: Nature communications 2015-01, Vol.6 (1), p.6111-6111, Article 6111
• Main Authors: Vedula, Sri Ram Krishna, Peyret, Grégoire, Cheddadi, Ibrahim, Chen, Tianchi, Brugués, Agustí, Hirata, Hiroaki, Lopez-Menendez, Horacio, Toyama, Yusuke, Neves de Almeida, Luís, Trepat, Xavier, Lim, Chwee Teck, Ladoux, Benoit
• Format: Article
• Language: English
• Subjects: 13; 14; 631/57/2267; 631/57/2270; 631/80/79/750; Actin Cytoskeleton - metabolism; Actins - chemistry; Actomyosin - metabolism; Animals; Biomechanics; Biomecànica; Cell Adhesion; Cell Line, Tumor; Cell Proliferation; Computer Simulation; Cèl·lules epitelials; Dogs; Environmental Engineering; Environmental Sciences; Epithelial cells; Epithelium - metabolism; Extracellular Matrix - metabolism; Humanities and Social Sciences; Humans; Life Sciences; Madin Darby Canine Kidney Cells; Microscopy, Atomic Force; Microscopy, Confocal; Models, Theoretical; multidisciplinary; Science; Science (multidisciplinary); Teixits (Histologia); Tissues
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms7111

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. Closure of epithelial gaps such as wounds is thought to involve contraction of an actomyosin ‘purse-string’. By creating non-adherent gaps to exclude contributions of adhesive protrusion, the authors find that large-scale tension, more than purse-string contraction, mediates closure.