Histological and single cell transcriptomic analysis of human retinal organoid models of Leber Congenital Amaurosis identifies endoplasmic reticulum stress as a common degenerative pathway
This study utilized human stem cell derived retinal organoids to characterize two models of Leber Congenital Amaurosis.  Using CRISPR/Cas9, we generated CRB1 and RPGRIP1 KO cell lines and differentiated WT and KO lines into retinal organoids.  Single cell capture was performed using Dropseq at days 70, 90, 120, 150, 190, and 225 of differentiation.  We report upregulation of DDIT3 in both KO organoids relative to WT and confirm DDIT3 induction at the protein level by immunohistochemistry.  These results indicate that these genetically different models of disease converge on endoplasmic reticulum stress and DDIT3 induction as a shared degenerative pathway.  Therapeutic targeting of ER stress could help alleviate the degenerative phenotype in cases where diseased photorececeptors suffer ER stress. Overall design: single cell RNAseq of wild type, RPGRIP1 KO, and CRB1 KO human retinal organoids at days 70, 90, 120, 150, 190, and 225