Exosomes as a Novel Multitarget Approach to Promote Growth of Corneal Sensory Neurons

Abstract

Purpose : Several growth factors, lipids and microRNAs can influence the regeneration of corneal nerves after injury. However, they have been primarily used as single entities with variable results. Here we propose the use of exosomes, which carry as “cargo” many of these regenerative factors, as a multitarget approach to enhance nerve growth.

Methods : Exosomes from cultured human corneal mesenchymal stem cells (cMSCs) and bone marrow mesenchymal stem cells (BM-MSCs) were isolated using ultracentrifugation. Trigeminal ganglia neurons from adult mice were cultured in neurobasal A media alone (negative control), supplemented with nerve growth factor (NGF) as a positive control, or supplemented with exosomes derived from cMSCs or BM-MSCs. Neurons were observed for four days and subsequently fixed with paraformaldehyde (PFA) and stained with beta-tubulin to evaluate neurite growth. Treatment conditions were masked to prevent bias and neurons were imaged and traced using Neurolucida software. Finally, branched-length and Sholl analysis were performed. Experiments were repeated for each treatment condition (n=3).

Results : Neurons treated with exosomes derived from BM-MSCs had an average neurite length of 576 um, while those in the control and NGF group had an average length of 288 and 529 um respectively. Additionally, Sholl analysis indicated that neurons from the BM-MSC exosome group had greater complexity than controls. Exosomes derived from cMSCs did not show as strong of an effect, with an average neurite length of 433 um.

Conclusions : Our results indicate a possible neurotrophic effect of exosomes. Neurons treated with exosomes displayed greater neurite growth and complexity than controls. Additional work will evaluate the effects of stem cell derived exosomes on in-vivo models of corneal nerve injury.

This is a 2021 ARVO Annual Meeting abstract.