Glia-Neuron Interactions in the Retina Can Be Studied in Cocultures of Muller Cells and Retinal Ganglion Cells

Glia-neuron partnership is important for inner retinal homeostasis and any disturbances may result in retinal ganglion cell (RGC) death. Muller cells support RGCs with essential functions such as removing excess glutamate and providing energy sources. The aim was to explore the impact of Muller cells on RGC survival. To investigate the Muller cell/RGC interactions we developed a coculture model, in which primary Muller cells were grown in inserts on top of pure primary RGC cultures. The impact of starvation and mitochondrial inhibition on the Muller cell ability to protect RGCs was studied. Moreover, the ability of Muller cells to remove glutamate from the extracellular space was investigated. RGC survival was evaluated by cell viability assays and glutamate uptake was assessed by kinetic uptake assays. We demonstrated a significantly increased RGC survival in presence of untreated and prestarved Muller cells. Additionally, prestarved Muller cells significantly increased RGC survival after mitochondrial inhibition. Finally, we revealed a significantly increased ability to take up glutamate in starved Muller cells. Overall, our study confirms essential roles of Muller cells in RGC survival. We suggest that targeting Muller cell function could have potential for future treatment strategies to prevent blinding neurodegenerative retinal diseases.