Comparison of the Response to the CXCR4 Antagonist AMD3100 During Development of Retinal Organoids Derived from ES Cells and of Zebrafish Retina

Abstract

Retinal organoids generated from embryonic stem cells or iPSCs recreate the key structural and functional features of mammalian retinal tissue in vitro. However, the differences in development of retinal organoids and normal retina in vivo are not well defined. Previous studies have demonstrated that C-X-C chemokine receptor type 4 (CXCR4) plays a key role in neurogenesis and optic nerve development in the retina. Thus, in the present study, we analyzed the development of retinal organoids and zebrafish retina after inhibition of CXCR4 with the antagonist AMD3100. Our data indicated that CXCR4 was mainly expressed in ganglion cells in retinal organoids and was not expressed in amacrine or photoreceptor cells. AMD3100 treatment reduced the retinal organoid generation ratio by approximately 40% and induced abnormal morphological changes. Moreover, CXCR4 blockade impaired differentiation of retinal cells in the organoids. The numbers of ganglion cells, amacrine cells, and photoreceptors were decreased by approximately 25-30% in organoids treated with AMD3100 compared to those in the control. Abnormal locations of ganglion, amacrine, and photoreceptor cells were observed in organoids treated with AMD3100. Neuronal axon outgrowth was also damaged in retinal organoids. Most results were similar to the data obtained in zebrafish retina. A decrease in ganglion cells, amacrine cells, and photoreceptors and the distribution of neural outgrowth induced by AMD3100 treatment in zebrafish retina were consistent with those detected in organoids, except that photoreceptors did not show mislocalization. Abnormal photoreceptor ensembles, such as ‘rosettes’, induced by AMD3100 treatment in the organoids were not detected in zebrafish retina. Therefore, our study suggests that retinal organoids may be a reliable model for reproduction of retinal development; however, certain differences between organoids and the retina in vivo were detected.