Establishment of a new cell model to identify drugs curtailing axonal mitochondria depletion in ADOA retinal ganglion cells

Autosomal dominant optic atrophy (ADOA) is a hereditary optic neuropathy characterized by the progressive bilateral loss of vision for which no treatment currently exists. Mutations in the nuclear encoded mitochondrial protein Optic Atrophy 1 (Opa1) are associated with ADOA which affect primarily Retinal Ganglion Cells (RGCs). Upon RGC death, the optic nerve composed of RGC axons degenerates resulting in blindness. The Scorrano lab has demonstrated that RGCs carrying mutated Opa1 display excess autophagy, accumulation of autophagosomes in axonal hillocks and mitochondrial depletion along axons, all associated with loss of vision in an ADOA mouse model. Remarkably, genetic inhibition of autophagy restored both axonal mitochondria distribution and vision in ADOA mice. We hence reasoned that pharmacological inhibition of pathways connecting ADOA mitochondria to autophagy hyperactivation could restore axonal mitochondrial distribution in ADOA RGCs, ultimately interrupting the pathogenetic cascade that leads to blindness. To this end, we seek to perform a high content imaging-based drug screening to identify compounds rescuing axonal mitochondrial content in ADOA RGCs. Such large-scale experiment however highlighted the technical bottleneck that is to work with primary mouse RGCs. Indeed, isolating primary RGC from mice cannot provide the sufficient amount of biological material that is necessary. To meet this demand, we have generated the first immortalized RGC line which will also facilitate our in vitro studies overall.