Abstract
Purpose :
The lack of regeneration found in the adult retina following optic nerve injury has led to the study of tissue engineered cell delivery methods. However, when designing these delivery devices, it is necessary to orient and polarize retinal ganglion cell (RGC) axon and dendrite growth. During development, this polarization is the result of neurotrophic factors and the developing retina’s extracellular matrix (ECM). Here we investigate how specific ECM components regulate RGC axon and dendrite outgrowth.
Methods :
To identify potential ECM components which regulate RGC axon and dendrite outgrowth, RGC integrin expression during development was analyzed. ECM proteins which bind to these integrins were identified and RGC neurite outgrowth for both control and pro-regenerative (Pten KO) RGCs were measured in two dimensional (2D) cultures. RGCs were analyzed for longest neurite, total neurite outgrowth as well as number of axons and dendrites per cell. We further examined neurite outgrowth of these cells in a three-dimensional (3D) hydrogels that composed of these same ECM components or decellularized central nervous system (CNS) tissues-hydrogels.
Results :
RGCs cultured on laminin, fibronectin, and vitronectin produced significantly longer neurite outgrowth while those cultured on laminin produced a significantly longer average neurite length. RGCs cultured on collagen and fibrinogen produced a greater number of dendrites whereas laminin produced the largest number of axons per cell. Data from 3D hydrogel experiment suggests that as was observed in 2D experiments, RGCs cultured on hydrogels containing laminin resulted in an increased neurite outgrowth while hydrogels produced from decellularized CNS tissues were able to increase neurite outgrowth while also promoting a more complex dendrite structure.
Conclusions :
RGCs, both control and Pten KO, cultured on lamanin and fibronectin substrates produced significantly longer axons and average neurite length. RGCs cultured on lamanin produced an increased number of axons per cell, but produced fewer dendrites than extended on other protein substrates suggesting that laminin may be best suited for axonal growth, whereas collagen and fibrinogen may be better suited for dendritic growth as we construct 3D model to study RGC polarization.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.