Abstract
Purpose :
Epithelial corneal wound healing is a multifaceted process that encompasses cell proliferation, migration, and communication from the corneal stroma. Upon corneal injury, bi-directional crosstalk between the epithelium and stroma via extracellular vesicles (EVs) has been reported. We previously demonstrated that human corneal epithelial cell (HCEC) EVs can promote corneal fibroblast (FB) to myofibroblast (MFB) differentiation; however, the mechanisms by which, corneal stromal EVs exert their effects on the corneal epithelium remains unclear. Here, we investigated the roles of corneal stromal (keratocyte (KER), FB, and MFB) EVs in epithelial corneal wound healing.
Methods :
EVs were isolated from corneal KER, FB, and MFB conditioned media by using differential ultracentrifugation and characterized by western blotting (WB), transmission electron microscopy (TEM), Zetaview™ nanoparticle tracking analysis (NTA) and Zeta (ζ) potential. The HCEC’s migratory ability and cell velocity following PKH26-labelled KER-/FB-/MFB-EV treatment was assessed in a scratch assay and determined by brightfield/immunofluorescent microscopy. HCEC’s viability, proliferative and apoptotic activity following EV treatment was also assessed by a WST-8 and a Caspase-Glo® 3/7 assay. KER-/FB-/MFB-EV protein cargo was determined by mass spectrometry and ingenuity pathway analysis.
Results :
WB revealed that FB-/MFB-EVs were enriched for CD63, CD81, INTGNAV and THBS1 compared to KER-EV, whilst all EVs were negative for GM130 as a negative control. All EVs showed minimal differences in biophysical properties (NTA, TEM and ζ-potential). MFB-EVs significantly increased HCEC migration and cell velocity in our scratch assay compared to KER-/FB-EVs and untreated controls. MFB-EV treatment elevated HCEC proliferation and lowered apoptosis levels compared to KER-/FB-EVs. At the proteomic level, we observed the MFB-EV protein cargo showed a >2-fold change in CXCL12, MMP1, COL6A1/-2/-3, TGFBI and EFEMP1 compared to KER-/FB-EVs; with other proteins unique to KER-/FB-EVs.
Conclusions :
These findings highlight that MFB-EVs contains a unique protein cargo that promotes HCEC-migration, cell velocity, and proliferation compared to KER-/FB-EVs. Understanding these elements may offer novel modalities to accelerate epithelial corneal wound healing and future studies in promoting scarless-wound healing.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.