Mechanics of epithelial tissues during gap closure

Abstract

The closure of gaps is crucial to maintaining epithelium integrity during developmental and repair processes such as dorsal closure and wound healing. Depending on biochemical as well as physical properties of the microenvironment, gap closure occurs through assembly of multicellular actin-based contractile cables and/or protrusive activity of cells lining the gap. This review discusses the relative contributions of 'purse-string' and cell crawling mechanisms regulated by cell-substrate and cell-cell interactions, cellular mechanics and physical constraints from the environment.

Upper and lower airway remodelling mechanisms in asthma, allergic rhinitis and chronic rhinosinusitis: The one airway concept revisited

“…19 The repair process begins with the deposition of ECM proteins over the denuded epithelium. 20 The ECM matrix acts as a substrate over which the basal epithelial cells at the 'wound edge' can attach to, proliferate, flatten out and migrate over and is composed of the remnant components of the BM, such as, type IV collagen and laminin, and blood-derived factors including fibrin and fibronectin. Activation of the attenuated fibroblast sheath is evident, particularly in response to signals from the transforming growth fac- 29 This may be related to the ability of IL-13 to induce the production of TGF-b1, although IL-13 can also induce airway fibrosis in TGF-b1-independent pathways.…”

Human fetal wound healing: a review of molecular and cellular aspects

“…Cell adhesion molecules (fibronectin and tenascin) and cell surface receptors (integrins) appear earlier in the healing of fetal wound compared to post-native wounds, which potentially allows faster cell infiltration into the injured dermis and faster migration rate fibroblasts [25]. During fetal development, tenascin facilitates cell movement, and fibronectin facilitates anchoring.…”

An orientation‐independent DIC microscope allows high resolution imaging of epithelial cell migration and wound healing in a cnidarian model

“…Numerous wound healing studies in tissue culture cells and in embryos have revealed that, in many cases, lamellipodia are produced by cells at the wound margin, and these cells migrate into the wound area (reviewed in Begnaud et al, 2016). When the edges of lamellipodia meet across the gap they establish cell-cell junctions and restore the integrity of the epithelial cell sheet.…”

“…Clytia is ideal for imaging epithelial cells because they occur as a flat squamous monolayer that covers the surface of the Clytia medusa. Epithelial cell sheets occur in all animals and are easily damaged by abrasion, surgery, or normal events such as the passage of food in the gut (Evans et al, 2013;Begnaud et al, 2016). Gaps must be rapidly closed to prevent infection and disease (Han & Ceilley, 2017).…”

“…Therefore, understanding how cells in the epithelial sheet recognize and close a wound is of tremendous importance as a basic science question and for clinical applications. Epithelial cell dynamics are difficult to study in intact animals or tissues; therefore, much of our understanding of epithelial wound healing comes from artificially wounded monolayers of epithelial cells grown in tissue culture (reviewed in Begnaud et al, 2016). Although epithelial cells are easy to visualize and manipulate in culture, it is important to develop in vivo models to complement the tissue culture approach.…”