Abstract
Background: The mammalian eye is a complex organ, comprising different highly specialized tissues derived from various cell linages, including neural ectoderm, surface ectoderm, neural crest and the periocular mesenchyme. Great efforts have been made to design protocols for obtaining ocular cells from human stem cells to model diseases or for regenerative purposes, but the complex crosstalk between ocular cell types driving self-organizing growth is usually limited by restricted experimental designs. Current protocols are overall focused on the isolation of retinal, retinal pigment epithelium (RPE) or corneal cells. Here, we obtained multi-ocular organoids from human induced pluripotent stem cells. Methods: We sought to establish a simple method to induce eye field-commitment in 2D hiPSC cultures with the aim of obtaining self-organized multi-zone ocular progenitor cells in 3 weeks. From this starting point, we generated 3D multi-ocular organoids from the same culture, recapitulating important cellular features of the developing eye. Results: Self-formed multi-zone ocular progenitors in 2D culture spanned the neuroectoderm, surface ectoderm, neural crest and RPE. After manual isolation and growth in suspension, they develop into different 3D multi-ocular organoids composed of multiple cell lineages: retinal pigment epithelium, retina and cornea which could be also generated individually. Within these organoids, retinal regions display correct layering and harbor all major retinal cell subtypes as well as retinal morphological cues, whereas corneal regions closely resemble the transparent ocular-surface epithelium with characteristics of corneal, limbal and conjunctival epithelial cells. RPE also arranged to form organoids composed of polarized pigmented epithelial cells at the surface, full-filled with collagen matrix. Conclusions: The multi-ocular organoids offer a new platform to study early human eye development and disease, and provide a source of human ocular cells from the same individual.
Efficient differentiation of human embryonic stem cells to retinal pigment epithelium under defined conditions
