Embryonic Stem Cell-derived
Retinal Pigment Epithelium and Photoreceptor Cells
Early: Transient loss of vision
Mid-term: The lines of an object look bent like waves. With further development, the center of the object appears dark and is not visible, creating a blank space or the center of the object is not visible as if it had been erased
Terminal: Loss of vision
Differentiation into RPE cells was confirmed as proteins known to be specifically expressed in RPE cells, namely, ZO1, Mitf, Pax6, Bestrophin, and RPE65, were observed.
FITC-labeled latex beads and FITC-labeled photoreceptor outer segment were treated on differentiated RPE cells to observe phagocytosis, one of the main functions of RPE cells. As a result, an influx of fluorescent substances into RPE cells was observed. Thus, phagocytosis of differentiated RPE cells was confirmed.
ZO1/FITC-labeled latex beads
ZO1/FITC-labeled photoreceptor outer segments
Through morphological verification of differentiated RPE cells using electron microscope, phagosome (A), a typical structure of RPE cells for phagocytosis, tight junction (A*) for cell-cell interactions, melanin granule (A**) for pigmentation and microvilli (B) used in phagocytosis were identified.
It was confirmed that differentiated RPE cells secrete PEDF and VEGF, the growth factors typically secreted from mature RPE cells, at a level similar to that of the positive control group (adult RPE cell line).
Differentiation into photoreceptors was confirmed as proteins known to be specifically expressed in photoreceptors, namely, blue opsin, red opsin, PDE6b, recoverin, and rhodopsin were observed.
When photoreceptors undergo an optical transmission signal, the concentration of cyclic GMP (Guanosine Monophosphate) becomes lower in photopic vision than in scotopic vision. The experiment confirmed the function of differentiated photoreceptors as the cyclic GMP decreased more in photopic vision (light) than in scotopic vision (dark).
When two types of TED-R cells were transplanted respectively into model animals with macular degeneration, the thickness of the outer nuclear layer (ONL), which became thinner due to macular degeneration, showed improvement compared to that of the control group.
When two types of TED-R cells were transplanted respectively into model animals with macular degeneration, the visual performance showed improvement as it was observed that the electroretinogram (b-wave), which decreased due to macular degeneration, was higher than that of the control group.