Abstract
Purpose: :
In response to cataract surgery the remaining lens epithelial cells migrate collectively onto the posterior capsule, effectively healing the wound inflicted by the loss of lens fiber cells. Recently, we identified an innate subpopulation of repair cells among the lens epithelium that rapidly migrate to the wound edge and are responsible for directing this wound response. A defining feature of repair cells is their high expression of vimentin. Here, we determine the role of vimentin intermediate filaments in repair cell function in response to lens injury.
Methods: :
These studies use an ex vivo chick embryo lens mock cataract surgery wound-repair model to examine whether vimentin is required for the repair cells to execute their function in regulating collective migration of lens epithelial cells across the posterior lens capsule. Vimentin function was blocked with the inhibitor WithaferinA (WFA). Efficacy of WFA was determined by its induction of vimentin cleavage and aggregation. Effect of WFA on migration of repair cells to the wound edge was determined by immunofluoresecence imaging; migration of lens epithelial cells across the posterior capsule was documented by photomicroscopy. Co-immunoprecipitation studies examined the potential that the role of vimentin in repair cell migration was linked to its association with myosin II, a motor protein that provides the driving force for actin-dependent movement.
Results: :
Exposure to WFA induced cleavage and aggregation of vimentin in lens wound-repair cultures. Perturbing vimentin function with WFA caused defects in repair cell behavior, resulting in a block in the movement of lens epithelial cells across the posterior lens capsule. Without vimentin function, the repair cells failed to move onto the posterior capsule and form a leading edge, both necessary for effective wound repair. Co-immunoprecipitation studies revealed for the first time an association between myosin II and vimentin, suggesting a crucial role for myosin II motors in vimentin-mediated migration of repair cells.
Conclusions: :
Our studies reveal a previously undiscovered function for vimentin in cell migration, shown here in the context of the repair cells that direct collective movement of the lens epithelium following cataract surgery, and the coordinate function of myosin II motor proteins with vimentin in this process.
Keywords: cytoskeleton • wound healing