Single-cell profiles of retinal neurons differing in resilience to injury reveal neuroprotective genes - Adult control RGCs treated with Actinomycin

Neuronal types in the central nervous system differ dramatically in their resilience to injury or insults. Here we studied selective resilience in mouse retinal ganglion cells (RGCs) following optic nerve crush (ONC), which severs their axons and leads to death of ~80% of RGCs in 2 weeks. To identify expression programs associated with differential resilience, we first used single-cell RNA-seq (scRNA-seq) to generate a comprehensive molecular atlas of 45 RGC types in adult retina. We tracked their survival after ONC, characterized transcriptomic, morphological, and physiological changes that preceded degeneration, and identified genes selectively expressed by each type. Finally, loss- and gain-of-function assays in vivo showed that manipulating some of these genes improved neuronal survival and axon regeneration following ONC. This study provides a systematic framework for parsing type-specific responses to injury, and demonstrates that these responses can be used to reveal molecular targets for intervention. In these experiments, we FACS sorted for retinal ganglion cells using a combination of a transgenic reporter (VGLUT2) and a surface protein (CD90) from dissociated retinas of adult (6-8 wk old) mice.