Direct-induced human retinal ganglion cells mimic fetal RGCs and are neuroprotective after transplant in vivo

ABSTRACT: Since retinal ganglion cells (RGCs) do not regenerate after injury, RGC replacement therapy could provide an approach to vision restoration in glaucoma and other optic neuropathies. Here we developed a rapid protocol for direct induction of RGC (iRGC) differentiation from human iPSCs and ESCs in less than two weeks, by overexpression of NGN2 in RGC survival-promoting medium supplemented with a Notch inhibitor. Neuronal morphology and neurite growth were observed within one week of induction. Immunostaining and qRT-PCR for characteristic RGC-specific genes confirmed identity. Calcium imaging was used to evaluate iRGCs’ electrophysiologic maturation, and demonstrated GABA-induced excitatory calcium influx characteristic of immature RGCs. Using single cell-RNA sequencing (scRNA-seq) we further delineated iRGCs’ differentiation and compared iRGC transcriptomic profiles to fetal human and retinal organoid-derived RGCs. Unbiased clustering showed high similarities of transcriptomic profiles among iRGCs, early-stage fetal human RGCs and early-stage retinal organoid-derived RGCs. However, for some markers, including BRN3a, BRN3b and NEFL, iRGCs demonstrated expression patterns more similar to fetal RGCs than to retinal organoid RGCs. After intravitreal injection into rodent eyes, transplanted iRGCs survived and migrated into host retinas where they were detected one week and one month after transplant. Prior optic nerve trauma to the recipient host did not significantly enhance or detract from iRGC integration, but iRGCs protected host RGCs from neurodegeneration. Taken together, these data demonstrate rapid iRGC generation in vitro into an immature cell with high similarity to human fetal RGCs and capacity for retinal integration after transplant, including after optic nerve injury. The simplicity of this system may benefit translational studies on human RGCs.

ORGANISM(S): Homo sapiens

PROVIDER: GSE200452 | GEO | 2022/04/10

REPOSITORIES: GEO