The adult vertebrate lens is composed of an anterior epithelial cell monolayer and lens fibre cells inside the acellular lens capsule, which constitutes a very thick basement membrane. Extracellular matrix proteins like laminin or fibronectin (FN) have been implicated in lens cell fate. Following cataract surgery, the epithelial cells of the lens are exposed to increased levels of fibronectin. Now (VanSlyke et al., 2018), Linda Musil and co-workers assess whether FN affects lens cell fate in a primary lens epithelial cell culture system. The authors find that upon exposure of these cells to FN, transforming growth factor β (TGFβ) signalling increases and both epithelial–myofibroblast transition and lens fibre cell differentiation are induced. These cell types are involved in the pathological condition of posterior capsule opacification (PCO) that arises as a complication to cataract surgery and disrupts vision. Furthermore, the authors show that FN exposure bypasses the need of the cells for bone morphogenetic protein (BMP) as part of normal fibroblast growth factor (FGF)-induced lens fibre cell differentiation. The inhibition of endogenous TGFβ restores the need for BMP, demonstrating the importance of the TGFβ–FN axis for lens cell fate. This study highlights a new target in the prevention of PCO as a complication of cataract surgery.
