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

Figure 2 Assessment of maturity and cellular composition of day 56 retinal organoids. A: Retinal organoids (RGs) after ethyl cinnamate clearing following whole-mount ICC for CHX10 (green) and CD44 (red) showing a more superficial layer of the structure; B: Proximal-most layer of OC seen in (A), clearly showing cells expressing CD44 and CHX10 in a non-overlapping but intercalated manner; C and D: Different RGs treated identically to (AB) showing similar distribution of retinal ganglion cells (RGCs) (CHX10-labelled) and Müller glia (CD44-labelled); E: Bright-field (BF) image of RG not showing invagination with the basal membrane (BM) outside. The apical layer (AL) is visible; F: BF image of invaginated RGs with BM inside (inverted). Visible are the retinal pigmented epithelium (RPE), retinal neural epithelium (RNE) and AL; G: Transmission electron microscopy (TEM) of the RPE. Visible are the AL with microvilli, mature pigmented granules and immature/young pigmented granules; H: TEM of the RNE with tight junctions at the AL and high density of mitochondria characteristic of neural tissues. Scale bar represents 100 mm as applies to A-F. Scale bar for G is 5 mm and 2 mm for H. AL: Apical layer; BM: Basal membrane; M: Mitochondria; MPG: Mature pigmented granules; MV: Microvilli; NE: Neural epithelium; TJ: Tight junctions.