Interactions between mesenchymal stem cells (MSCs) and trigeminal ganglion (TGs) improve neurite growth and elongation

Abstract

Purpose : Sensory innervation of the cornea is essential for the perception of stimuli critical for blinking, maintenance of hydration, and injury avoidance. Disease, infection and ophthalmic surgical procedures can all damage corneal central nerves, resulting in scarring and vision problems. Corneal nerves regenerate over several years, however, sub-basal nerve density never returns to normal. Despite the clinical need to promote corneal nerve regeneration, few specific therapeutic interventions are available. Cell therapy, specifically MSCs presents an attractive treatment option for enhancing nerve regeneration in this critical ocular structure. In this project, we studied the role of MSCs in corneal nerve regeneration.

Methods : Mouse TGs neurons were isolated from Thy1-YFP mice which have fluorescent corneal nerves. Human corneal MSCs (CO-MSCs) and bone marrow MSCs (BM-MSCs) were used. 2D and 3D co-culture system was developed to grow TGs in presence of each type of MSCs. The morphology of the TGs was monitored over 7 days. Cells were then fixed and immune-stained on day 7. Immunocytochemistry was performed to observe β3 tubulin and CD90 expression marker for TGs and MSCs respectively. Confocal microscopy and Neurolucida software used to analyze the density and length of the neurites in different conditions.

Results : Morphology observations illustrated enhanced axonal growth and survival over time in presence of MSCs compared to TG-only conditions. After 5 days, TGs started to shrink and finally die after 8 to 10 days whereas TGs in presence of MSCs showed enhanced survival after 2 weeks in culture. Immunostaining data (β3 tubulin/CD90) and then analysis using Neurolucida illustrated a significant increase in density and the complexity of the TGs in the co-culture system versus TGs alone. Finally, a significant increase in neuron branching was observed in 3D versus 2D.

Conclusions : These results demonstrate the distinct effect of MSCs in maintenance, growth, and elongation of neurites nerve regeneration over time. Further functional experiments will be performed to study the effect of MSCs in vivo and the mechanisms by which MSCs can promote corneal nerve regeneration after injury. These studies will enable us to develop highly novel therapeutics for the restoration of damaged corneal nerves and potentially, other ocular diseases.

This is a 2021 ARVO Annual Meeting abstract.