Abstract
Purpose :
A large body of evidence demonstrated the critical role of regulatory T cells (Tregs) in regulating wound repair and regeneration. However, the function of increased Tregs during corneal epithelial wound healing remained largely uncertain. We therefore aimed to investigate the role of Tregs in the corneal epithelial wound healing.
Methods :
Based on murine corneal epithelial abrasion model, Foxp3DTR/EGFP mice and anti-CD25 antibodies were applied to deplete in vivo Tregs and evaluate their role in corneal wound healing. Single-cell RNA sequencing (scRNA seq) was performed to systemically investigate the effect of Treg on corneal limbal epithelial stem cells (LESCs) and various immunocytes. Besides, exosome released from Tregs was isolated and used to determine the potential to treat corneal wound healing under different pathological scenarios. Additionally, exosomal proteomic approach and loss-of-function experiment were employed to explore the underlying mechanism.
Results :
When compared with the normal corneas, more accumulation of Tregs in the corneas during epithelial wound healing was observed. Specifical depletion of Tregs apparently impaired corneal epithelial wound closure, characterized by the lowered wound healing rate and decreased expression of Ki67 and GPHA2. Through scRNA seq analysis, some clusters of genes related with LSC function and epithelial proliferation showed a remarkably lowered expression in Treg-depleted group. By contrast, the proportions of several types of immunocytes (such as monocytes, macrophages and dendritic cells) in Treg-depleted corneas were obviously increased, the significant enrichment of inflammation-associated biological processes of the up-regulated genes in Treg-depleted corneas were also determined. More interestingly, we also found that the exosomes derived from Tregs promoted corneal epithelial wound healing, mechanistically relied on CD47, suggesting the possibility of exosome in the replace of Tregs’ function.
Conclusions :
Our findings demonstrated that Tregs in corneas play vital roles in maintaining corneal homeostasis, and further highlighted Treg-derived exosomes as an alternative approach for treating corneal epithelial wound healing.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.