Abstract
Purpose :
Exosomes are secreted by a broad range of cell types, known to facilitate intercellular communication, and considered to be a promising therapeutic tool for multiple diseases. We sought to define the role of exosomes isolated from cultured mouse corneal epithelial cells (CECs) and born marrow derived dendritic cells (BMDC) in modulating corneal wound healing in normal and diabetic mice.
Methods :
Exosomes were isolated from cultured TKE2 cells, a murine corneal epithelial progenitor cell line with or without wounding, and BMDCs using filtration and ultracentrifugation and verified with electron microscopy and Western blotting. The effects of TKE2 exosomes on wound healing and sensory nerve regeneration were assessed using streptozotocin (STZ)-induced diabetic C57BL/6 mice whereas BMDC exosomes in DC depleted mice.
Results :
Exosomes derived from the control and scratch-wounded TKE2 cells were 50-100 µm in size and expressed CD 63 and HSP70. Interestingly, Semaphorin-3C, a neuronal guidance cue protein, was only detected in the exosomes derived from scratched TKE2 cells. Recombinant Sema3C promoted corneal epithelial wound closure and sensory nerve regeneration in diabetic B6 mouse corneas. Exosomes isolated from scratched cultures accelerated delayed epithelial wound closure and sensory nerve regeneration much greater than that from unwounded TKE2 cells in STZ mouse corneas. Local depletion of DCs severely delayed epithelial wound healing and sensory nerve regeneration in normal corneas and these effects were reversed by the application of DC derived exosomes.
Conclusions :
Epithelium-scratch wound altered the content of exosomes, resulting in enhanced epithelial wound healing in diabetic mouse corneas. DCs may functionally be replaced by the exosomes they secreted in the cornea.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.