Abstract
Purpose :
Exosomes are known to transfer bioactive molecules among cells and play crucial roles in wound healing, angiogenesis, and cancer. We hypothesized that corneal epithelial cell-derived exosomes may gain access to the underlying stromal fibroblasts upon disruption of the epithelial basement membrane and that they induce signaling events essential for corneal wound healing.
Methods :
Exosomes were isolated from mouse corneal epithelial cells and fibroblasts using Total Exosomes Isolation Reagent (Invitrogen). Electron microscopy, dynamic light scattering, and detection of exosomal markers by Western blotting were performed to characterize exosomes. The effects of epithelial cell-derived exosomes on the proliferation of keratocytes/endothelial cells were determined using BrdU assays. The effect of epithelial cell-derived exosomes on alpha-smooth muscle actin expression on keratocytes was monitored by immunofluorescence staining under confocal microscopy. Proteomics analysis was performed to elucidate the biological activities of the epithelial cell derived-exosomes.
Results :
Corneal epithelial cell-derived exosomes were found to fuse to keratocytes in vitro and to induce myofibroblast transformation. In addition, epithelial cell derived-exosomes induced endothelial cell proliferation and ex vivo aortic ring sprouting. Multiple bioactive molecules including TGF-β, cell adhesion proteins, metalloproteinases, and chemokines were identified on epithelial cell-derived exosomes.
Conclusions :
Our results indicate that epithelial cell-derived exosomes mediate communication between corneal epithelial cells and corneal keratocytes as well as vascular endothelial cells. These findings demonstrate that epithelial cell-derived exosomes may be involved in corneal wound healing and neovascularization, and thus, may serve as targets for potential therapeutic interventions.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.