Enrichment of retinal ganglion and Müller glia progenitors from retinal organoids derived from human induced pluripotent stem cells - possibilities and current limitations.

BACKGROUND Retinal organoids serve as excellent human-specific disease models for conditions affecting otherwise inaccessible retinal tissue from patients. They permit the isolation of key cell types affected in various eye diseases including retinal ganglion cells (RGCs) and Muller glia. AIM To refine human-induced pluripotent stem cells (hiPSCs) differentiated into three-dimensional (3D) retinal organoids to generate sufficient numbers of RGCs and Muller glia progenitors for downstream analyses. METHODS In this study we described, evaluated, and refined methods with which to generate Muller glia and RGC progenitors, isolated them via magnetic-activated cell sorting, and assessed their lineage stability after prolonged 2D culture. Putative progenitor populations were characterized via quantitative PCR and immunocytochemistry, and the ultrastructural composition of retinal organoid cells was investigated. RESULTS Our study confirms the feasibility of generating marker-characterized Muller glia and RGC progenitors within retinal organoids. Such retinal organoids can be dissociated and the Muller glia and RGC progenitor-like cells isolated via magnetic-activated cell sorting and propagated as monolayers. CONCLUSION Enrichment of Muller glia and RGC progenitors from retinal organoids is a feasible method with which to study cell type-specific disease phenotypes and to potentially generate specific retinal populations for cell replacement therapies.