Generation of novel APBB2 SNP iPSC lines to study increased risk for glaucoma unique to individuals of African ancestry

Abstract

Purpose : Glaucoma has been found to occur more frequently and with higher severity in populations of African ancestry compared to other races, yet research in this population is lacking. A recent GWAS study identified a SNP in the gene APBB2 linked to increased risk for glaucoma uniquely within individuals of African ancestry. The discovery of this SNP provides an exciting opportunity to study why those of African ancestry populations are at increased risk for glaucoma. Human induced pluripotent stem cells (iPSCs) can model genetic diseases by differentiating stem cells into cell types associated with the disease state.

Methods : For the study of APBB2 and how a SNP at this locus may confer increased risk for glaucoma, we generated SNP mutant and isogenic control iPSCs from lines derived from donors of African ancestry using CRISPR/Cas9 gene editing approaches. These iPSC lines were then differentiated into retinal organoids followed by the isolation and maturation of retinal ganglion cells (RGCs), with assays to characterize neurodegenerative features including morphological analyses, functional assays by multielectrode array, and protein expression assays.

Results : We have successfully generated lines of human iPSCs with the APBB2 risk variant for glaucoma via CRISPR/Cas9 gene editing, along with paired isogenic controls. These cell lines were also engineered to express a BRN3b-mNeonGreen-Thy1.2 reporter for identification and purification of RGCs. Each of these cell lines was capable of robust differentiation into retinal organoids, which were then used for the purification and maturation of RGCs for downstream analyses. Ongoing experiments are focusing upon changes in RGC morphological features and functional properties.

Conclusions : These studies represent the first known attempt to develop iPSC-based models from individuals of African ancestry for the study of increased risk for glaucoma among this population. Ongoing studies with these cell lines will likely elucidate important cellular and molecular aspects that uniquely lead to this increased risk for glaucoma among the African ancestry population.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.