Abstract
Purpose: :
Recent studies have shown that after Descemet membrane endothelial keratoplasty (DMEK) corneal endothelial cells (CEC) can migrate from the donor corneal endothelium (CE) to the denuded Descemet membrane of the recipient. This could explain several reported cases where re-endothelization of the Descemet membrane occurred in patients with nearly complete graft detachment after DMEK. Since primary cilia assemble in migrating CEC involved in repair of wounded CE we tested the hypothesis that cilia are required for CEC polarization during directed cell migration in development and repair of the CE.
Methods: :
Identification and localization of cilia, bb, cell-cell contacts and IFT20 was achieved by immuno-confocal microscopy using antibodies directed to acetylated tubulin, γ-tubulin, ZO1 and IFT20, respectively. Morphometric analysis was conducted with ImageJ and graphs were generated with Prism (GraphPad) and ROSE software.Ciliary mutant mouse strains orpk and CAGG-creERTM; ift88flox/- were analyzed.
Results: :
To assess intracellular polarization during CEC migration in development and repair we have analyzed the intracellular position of two cellular organelles: the basal bodies and the Golgi apparatus by using anti-γ-tubulin and anti-IFT20 antibodies, respectively. In central CEC of wild-type mice the bb and the IFT20 were localized near the cell center. In contrast, the bb and IFT20 were shifted toward the periphery in CEC located at the CE periphery. Strikingly, the position of the bb and distribution of IFT20 in peripheral CEC was random in orpk mice that show short cilia and defective CE patterning. We confirmed that CEC neighboring a wound and involved in repair assemble a primary cilium but lose cytoplasmic acetylated microtubules (Blitzer et al., 2011 PNAS). In contrast, in CAGG-creERTM; ift88flox/-, mice lacking IFT88 we did not detect cilia on any CEC involved in repair, acetylated microtubules were still visible in the cytoplasm and CEC did not polarized and elongate toward the wound.
Conclusions: :
We have found that the cilium is required for directed cell migration of CEC during development and repair. The CE cilium could represent a novel target to enhance re-endothelialization of denuded Descemet membrane.
Keywords: cornea: endothelium • wound healing • development