Multiocular organoids from human induced pluripotent stem cells displayed retinal, corneal, and retinal pigment epithelium lineages

Helena Isla-Magrané,José García-Arumí,Anna Veiga,Anna Duarri

doi:10.1186/s13287-021-02651-9

Abstract

BackgroundRecently, great efforts have been made to design protocols for obtaining ocular cells from human stem cells to model diseases or for regenerative purposes. Current protocols generally focus on isolating retinal cells, retinal pigment epithelium (RPE), or corneal cells and fail to recapitulate the complexity of the tissue during eye development. Here, the generation of more advanced in vitro multiocular organoids from human induced pluripotent stem cells (hiPSCs) is demonstrated.MethodsA 2-step method was established to first obtain self-organized multizone ocular progenitor cells (mzOPCs) from 2D hiPSC cultures within three weeks. Then, after the cells were manually isolated and grown in suspension, 3D multiocular organoids were generated to model important cellular features of developing eyes.ResultsIn the 2D culture, self-formed mzOPCs spanned the neuroectoderm, surface ectoderm, neural crest, and RPE, mimicking early stages of eye development. After lifting, mzOPCs developed into different 3D multiocular organoids composed of multiple cell lineages including RPE, retina, and cornea, and interactions between the different cell types and regions of the eye system were observed. Within these organoids, the retinal regions exhibited correct layering and contained all major retinal cell subtypes as well as retinal morphological cues, whereas the corneal regions closely resembled the transparent ocular-surface epithelium and contained of corneal, limbal, and conjunctival epithelial cells. The arrangement of RPE cells also formed organoids composed of polarized pigmented epithelial cells at the surface that were completely filled with collagen matrix.ConclusionsThis approach clearly demonstrated the advantages of the combined 2D-3D construction tissue model as it provided a more ocular native-like cellular environment than that of previous models. In this complex preparations, multiocular organoids may be used to model the crosstalk between different cell types in eye development and disease.Graphical abstract

Highlights

Great efforts have been made to design protocols for obtaining ocular cells from human stem cells to model diseases or for regenerative purposes
The anterior segment of the eye is composed of the cornea, conjunctiva, limbus, lens and iris, which are derived from the lens placode that arises from the surface ectoderm (SE)
Multizone ocular precursor cells organized into neuroectoderm, neural crest and surface ectoderm areas Eye field commitment in the 2D Human induced pluripotent stem cells (hiPSC) cultures was induced by inhibiting BMP and Wnt pathways using noggin and DKK1 antagonists, respectively [45], and by activating FGF and Insulin growth factor 1 (IGF-1) pathways [37, 46] (Fig. 1A)

Summary

Introduction

Great efforts have been made to design protocols for obtaining ocular cells from human stem cells to model diseases or for regenerative purposes. Current protocols generally focus on isolating retinal cells, retinal pigment epithelium (RPE), or corneal cells and fail to recapitulate the complexity of the tissue during eye develop‐ ment. The anterior segment of the eye is composed of the cornea, conjunctiva, limbus, lens and iris, which are derived from the lens placode that arises from the surface ectoderm (SE). The cornea is the outer layer of the eye, is developed from the SE and controls and focuses the entry of light into the eye. This transparent layer is formed by a stratified epithelium, a collagen-rich stroma that is maintained by keratocytes, and the endothelium in the inner part [5]. The neural crest (NC)-mesenchymal ectoderm-derived component contributes to from the corneal stroma and endothelium, ciliary body, and melanocytes [7]

Objectives

Methods

Results

Discussion

Conclusion