Three-dimensional mechanical cooperativity optimises epithelial wound healing.

Epithelial tissues serve as critical physical barriers that protect organs, making their efficient repair essential upon damage. To achieve this, tissues must quickly react, forcing cells to rearrange and accommodate to achieve rapid wound closure. In the Drosophila wing disc, we previously showed how tissue fluidisation accelerated wound healing in 2D. However, the 3D aspect of tissue repair remains poorly understood. Here, we uncover a new mechanism that facilitates tissue repair through changing cell height. We find actomyosin contractile cables at the wound edge connecting the apical and basal cell surfaces, which indent the apical side of the tissue and deform the basement membrane, respectively. To assess the role of the different repair mechanisms, we develop a 3D vertex model allowing independent apical, lateral and basal behaviours. The model predicts that lateral cables play a role in regulating planar cell-cell intercalations, confirmed by Drosophila mutations affecting cell deformations. Our results demonstrate that lateral cables cooperate with the apical purse string to drive 3D cell shape changes and planar cell-cell intercalations for efficient wound repair.