Self-formation of concentric zones of telencephalic and ocular tissues and directional retinal ganglion cell axons

Telencephalon, optic stalk, and optic-cup in vertebrates are originated from adjacent fields in the anterior neuroplate. How these tissues develop coordinately along the midline-periphery axis is unclear. Here, we report the self-formation of a human telencephalon-eye organoid comprising concentric zones of FOXG1+ telencephalon, PAX2+ optic disc/stalk, VSX2+ neuroretina, and PAX6+ tissues along the center-periphery axis. FGFs and BMPs were expressed starting at early stages and subsequently exhibited concentric gradients, suggesting their involvement in tissue patterning and coordinated cell differentiation. Early differentiated retinal ganglion cells (RGC) grew axons towards and along a path defined by an adjacent PAX2+ cell population. Lens cells were also found. Single-cell RNA sequencing confirmed telencephalic and ocular cell identities, located PAX2+ cell populations mimicking the optic disc/stalk, and identified RGC-specific cell surface protein CNTN2. RGCs were isolated in one step via CNTN2 in a native condition, facilitating therapeutic development for RGC-related retinal diseases such as glaucoma. CONCEPT telencephalon-eye organoids at day 24 from one culture well were dissociated into single cells using activated Papain (Worthington Biochemical Corporation LS003126) following manufacturer’s instructions. Then, 10,000 dissociated cells were captured using Chromium Controller (10x Genomics), followed by library preparation following manufacturer’s instructions. The library was sequenced in one lane of Illumina HiSeq (2x150 bp) in GeneWIZ company.