Occluding junctions and epithelial wound repair

In epithelial tissues, cells tightly connect to each other through cell–cell junctions, but they also present the remarkable capacity of reorganizing themselves without compromising tissue integrity. Upon injury, simple epithelia efficiently resolve small lesions through the action of actin cytoskeleton contractile structures at the wound edge and cellular rearrangements. However, the underlying mechanisms and how they cooperate are still poorly understood. By using live imaging of wound repair in the fly Drosophila melanogaster and theoretical modeling Carvalho and collaborators reveal a novel and indispensable role for occluding junctions (OJs) in this process. They demonstrate that OJ loss of function leads to severe defects in wound-closure dynamics: instead of contracting, wounds dramatically increase their area. OJ mutants exhibit phenotypes in cell shape, cellular rearrangements, and mechanical properties as well as in actin cytoskeleton dynamics at the wound edge. The authors propose that OJs are required for wound closure by impacting on tissue mechanical properties, which in turn is crucial for the correct regulation of the cellular events occurring at the wound edge.

The article entitled “Occluding junctions as novel regulators of tissue mechanics during wound repair”was published in The Journal of Cell Biology.