title: Mechanics of epithelial closure over non-adherent environments.
abstract: 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.
authors.affiliation: Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore.
authors.forename: Sri Ram Krishna
authors.initials: SR
authors.lastname: Vedula
authors.affiliation: 1] Institut Jacques Monod (IJM), CNRS UMR 7592 and Université Paris Diderot, 75013 Paris, France [2] Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, and CIBERES, 08036 Barcelona, Spain.
authors.forename: Grégoire
authors.initials: G
authors.lastname: Peyret
authors.affiliation: 1] Sorbonne Universités, UPMC Univ Paris 06 and CNRS UMR 7598, Laboratoire Jacques-Louis Lions, F-75252 Paris, France [2] INRIA-Paris-Rocquencourt, MAMBA Team, Domaine de Voluceau, BP105, 78153 Le Chesnay Cedex, France.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Cheddadi
authors.affiliation: Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore.
authors.forename: Tianchi
authors.initials: T
authors.lastname: Chen
authors.affiliation: Institute for Bioengineering of Catalonia, C/ Baldiri Reixac 10-12, 08028 Barcelona, Spain.
authors.forename: Agustí
authors.initials: A
authors.lastname: Brugués
authors.affiliation: Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hirata
authors.affiliation: Institut Jacques Monod (IJM), CNRS UMR 7592 and Université Paris Diderot, 75013 Paris, France.
authors.forename: Horacio
authors.initials: H
authors.lastname: Lopez-Menendez
authors.affiliation: 1] Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore [2] Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543 Singapore [3] Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Toyama
authors.affiliation: 1] Sorbonne Universités, UPMC Univ Paris 06 and CNRS UMR 7598, Laboratoire Jacques-Louis Lions, F-75252 Paris, France [2] INRIA-Paris-Rocquencourt, MAMBA Team, Domaine de Voluceau, BP105, 78153 Le Chesnay Cedex, France.
authors.forename: Luís Neves
authors.initials: LN
authors.lastname: de Almeida
authors.affiliation: 1] Institute for Bioengineering of Catalonia, C/ Baldiri Reixac 10-12, 08028 Barcelona, Spain [2] Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys, 23 08010 Barcelona, Spain [3] Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, and CIBERES, 08036 Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Trepat
authors.affiliation: 1] Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore [2] Department of Biomedical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575, Singapore [3] Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575, Singapore.
authors.forename: Chwee Teck
authors.initials: CT
authors.lastname: Lim
authors.affiliation: 1] Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore [2] Institut Jacques Monod (IJM), CNRS UMR 7592 and Université Paris Diderot, 75013 Paris, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Ladoux
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D000199:Actins / Q000737:chemistry; D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003198:Computer Simulation; D004285:Dogs; D004848:Epithelium / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D008962:Models, Theoretical
chemical_list: D000199:Actins; D000205:Actomyosin