Corneal scarring is a leading cause of blindness in the world. In this study, we explored the therapeutic potential of corneal stromal stem cell (CSSC)-derived secretome in a mechanical debridement mouse model of corneal scarring. CSSC secretome was able to promote scarless corneal wound healing. The mechanisms include 1) dampening inflammation with reduced CD45+, CD11b+/GR1+, and CD11b+/F4/80+ inflammatory cells in the wounded corneas; 2) reducing fibrotic extracellular matrix deposition such as collagen IV, collagen 3A1, SPARC, and α-SMA; 3) rescuing sensory nerves. The proteomic analysis shows upregulated proteins related to wound healing and cell adhesion which boost scarless wound healing. It also shows upregulated neuroprotective proteins in CSSC secretome related to axon guidance, neurogenesis, neuron projection development, and neuron differentiation. Four unique complement inhibitory proteins CD59, vitronectin, SERPING1, and C1QBP found in CSSC secretome contribute to reducing a complement cascade mediating cell death and membrane attacking complex autoantibodies after corneal injury. This study provides novel insights into mechanisms of stem cell secretome induced scarless corneal wound healing and neuroprotection and identifies regenerative proteins in the CSSC secretome.

Significance Statement

In this study, we report the therapeutic role of corneal stromal stem cell (CSSC) secretome for scarless corneal wound healing and corneal sensory nerve rescuing. We uncovered that CSSC secretome dampens inflammation, reduces fibrosis, induces sensory nerve regeneration, and rescues corneal cells by inhibiting the complement system in the wounded mouse corneas. This study provides pre-clinical evidence for the use of CSSC secretome as a biologic treatment for corneal scarring to prevent corneal blindness. We delineated a plethora of proteins in the CSSC secretome, which individually or in combination have the potential as future therapies for scarless corneal wound healing.