As an extracellular structure, the basement membrane separates tissue layers and surrounds muscles and organs. The basement membrane serves as a mechanical scaffold and promotes molecular signalling to adjacent cells. However, despite its many roles, the mechanisms for assembly and repair of the basement membrane are not well known. Now, Andrea Page-McCaw and colleagues (Howard et al., 2019) set out to establish a model for basement membrane damage and repair using the gut basement membrane of Drosophila adults. By feeding the intestinal irritant dextran sodium sulfate (DSS) to flies, the authors found that DSS incorporates into the basement membrane and causes its expansion and a decrease of basement membrane stiffness. This DSS-induced damage induces a contracted rounded appearance in peristalsis muscles, which are surrounded by basement membrane. Removal of DSS from the diet allows the basement membrane to repair. The authors show that basement membrane repair requires cross-linking of its main component collagen IV; specifically, cross-linking stabilizes newly incorporated repaired, rather than damaged collagen. Taken together, this study suggests that the gut basement membrane is a dynamic matrix and proposes a DSS-based experimental model for damage and repair of the basement membrane.
