FIGURE 3.

SSTR2‐mediated somatostatin signalling regulates fate switch between cone and rod photoreceptor. (A) The transcriptional co‐expression network of developing photoreceptor lineage in the human fetal retina showing the close connection between SSTR2 and NRL. (B) Schematic diagram showing treatment details of SSTR2 ligand somatostatin and its inhibitor CYN154806. (C) Representative images of activated and internalized SSTR2 (green) co‐stained with PRDM1 (red) in control and somatostatin (SST) and CYN154806 treatment (n = 6). Scale bar = 50 μm. (D) The immunostaining of NRL and PDE6H expression. (E) Immunohistochemical quantification analysis of cone photoreceptor marker PDE6H and rod photoreceptor precursor marker NRL. *p < 0.05. (F) Cone photoreceptors labelled by RXRG (green) and PDE6H (red) show a significant increase in CYN154806‐treated organoids (n = 4) and a decrease in SST‐treated organoids (n = 5). Scale bar = 50 μm. (G) Immunohistochemical quantification analysis of cone photoreceptor marker PDE6H and rod photoreceptor precursor marker NR2E3. *p < 0.05. Scale bar = 50 μm. (H) Immunofluorescence staining of rod photoreceptor marker NR2E3 (green) in somatostatin (SST) and SSTR2 inhibitor CYN154806 treatment