Self-organization, quality control, and preclinical studies of human iPSC-derived retinal sheets for tissue-transplantation therapy.

Three-dimensional retinal organoids (3D-retinas) are a promising graft source for transplantation therapy. We previously developed self-organizing culture for 3D-retina generation from human pluripotent stem cells (hPSCs). Here we present a quality control method and preclinical studies for tissue-sheet transplantation. Self-organizing hPSCs differentiated into both retinal and off-target tissues. Gene expression analyses identified the major off-target tissues as eye-related, cortex-like, and spinal cord-like tissues. For quality control, we developed a qPCR-based test in which each hPSC-derived neuroepithelium was dissected into two tissue-sheets: inner-central sheet for transplantation and outer-peripheral sheet for qPCR to ensure retinal tissue selection. During qPCR, tissue-sheets were stored for 3-4 days using a newly developed preservation method. In a rat tumorigenicity study, no transplant-related adverse events were observed. In retinal degeneration model rats, retinal transplants differentiated into mature photoreceptors and exhibited light responses in electrophysiology assays. These results demonstrate our rationale toward self-organizing retinal sheet transplantation therapy.

Publisher Correction: Preconditioning the Initial State of Feeder-free Human Pluripotent Stem Cells Promotes Self-formation of Three-dimensional Retinal Tissue.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Preconditioning the Initial State of Feeder-free Human Pluripotent Stem Cells Promotes Self-formation of Three-dimensional Retinal Tissue.

A three-dimensional retinal tissue (3D-retina) is a promising graft source for retinal transplantation therapy. We previously demonstrated that embryonic stem cells (ESCs) can generate 3D-retina in vitro using a self-organizing stem cell culture technique known as SFEBq. Here we show an optimized culture method for 3D-retina generation from feeder-free human pluripotent stem cells (hPSCs). Although feeder-free hPSC-maintenance culture was suitable for cell therapy, feeder-free hPSC-derived aggregates tended to collapse during 3D-xdifferentiation culture. We found that the initial hPSC state was a key factor and that preconditioning of the hPSC state by modulating TGF-beta and Shh signaling improved self-formation of 3D-neuroepithelium. Using the preconditioning method, several feeder-free hPSC lines robustly differentiated into 3D-retina. In addition, changing preconditioning stimuli in undifferentiated hPSCs altered the proportions of neural retina and retinal pigment epithelium, important quality factors for 3D-retina. We demonstrated that the feeder-free hiPSC-derived 3D-retina differentiated into rod and cone photoreceptors in vitro and in vivo. Thus, preconditioning is a useful culture methodology for cell therapy to direct the initial hPSC state toward self-organizing 3D-neuroepithelium.