Abstract
Purpose :
Corneal wound healing is a complex and coordinated process involving injury repair to the epithelial layer and stimulation of limbal epithelial cell (LEC) migration and proliferation for tissue regeneration. Prevention of excessive stromal myofibroblast activation and vascular ingrowth is imperative to avoid fibrosis and angiogenesis, which can compromise corneal transparency. We hypothesize that MG53 constitutes an active component of corneal healing and regeneration by maintaining the health of LEC.
Methods :
An alkaline-induced injury was introduced to the corneas of wildtype (WT) and MG53 knockout (mg53-/-) mice (n=6); healing was monitored for 14 days. Tissue from mice that overexpress MG53 or their littermate controls (n=6) were evaluated for expression of the LEC marker ΔNp63α. Cultured murine LEC were treated with Alexa-647-labeled recombinant human (rh)MG53 to determine protein uptake (n=4). Further, in the presence or absence of rhMG53, LEC underwent a colony formation assay (n=6), a microglass bead injury model followed by an LDH assay to evaluate viability (n=6), and a scratch assay to evaluate migration and proliferation (n=4).
Results :
Mice with ablation of MG53 showed reduced expression of ΔNp63α. Further, following injury, the mg53-/- corneas exhibited hallmarks of limbal stem cell deficiency with compromised corneal epithelial regeneration, increased goblet cell infiltration, and pronounced stromal fibrosis and vascularization, compared to WT littermates. Mice with sustained elevation of systemic MG53 circulation show enhanced ΔNp63α expression within the limbus and increased tissue regenerative capacity with enhanced LEC function. Cultured LEC treated with rhMG53 internalized the protein and, when compared to controls, had significantly increased viability following injury (p<0.001), more colony forming units (p<0.01), and improved migration and proliferation (p<0.01).
Conclusions :
We demonstrate that the protein MG53 is important in modulating LEC function associated with corneal injury-repair. Based on our data, we conclude that MG53 constitutes an active component of corneal injury-repair and regeneration by maintaining the health of LECs, as well as controlling the stromal fibrotic response.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.