Abstract
Purpose :
The extracellular matrix (ECM) plays a critical role during periocular neural crest (pNC) migration and maturation of corneal layers. Nephronectin (Npnt), is an ECM protein that is involved in several cellular processes during development, disease, and homeostasis, but its function in the cornea remains unknown. This study characterizes the novel expression of Npnt and examines its function during corneal development.
Methods :
In situ hybridization and immunofluorescence were utilized to determine the spatiotemporal expression of Npnt and its receptor integrin alpha 8 (Itgα8) during chick corneal development. Virus mediated knockdown and overexpression of Npnt or Itgα8 was utilized to determine the function of Npnt. Corneas were collected at embryonic stages (E)4, E6, E7, E9, and E15, and analyzed for morphology and cell proliferation. In vitro studies were performed with pNC explants cultured on poly-lysine-, fibronectin-, or Npnt-coated slides and cell migration was tracked by time-lapse video microscopy.
Results :
Npnt is transiently localized in the migratory pNC, primary stroma, and Bowman’s layer while Itgα8, is expressed by migratory pNC. Knockdown of Npnt or Itgα8 resulted in corneal thinning and compromised epithelial integrity. Conversely, overexpression of Npnt resulted in corneal thickening, but this was not associated with increased cell proliferation. In vitro studies showed significant increase in pNC migration on Npnt compared to fibronectin substrate, and that migration on Npnt substrate was significantly reduced by inhibition of integrin α8β1 signaling.
Conclusions :
Combined, our results show novel expression of Npnt and indicate that Npnt-Itgα8β1 signaling is critical for regulating pNC migration and epithelial integrity during corneal development.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.