Assessing Variant Causality and Severity Using Retinal Pigment Epithelial Cells Derived from Stargardt Disease Patients.

TitleAssessing Variant Causality and Severity Using Retinal Pigment Epithelial Cells Derived from Stargardt Disease Patients.
Publication TypeJournal Article
Year of Publication2022
AuthorsMatynia, A, Wang, J, Kim, S, Li, Y, Dimashkie, A, Jiang, Z, Hu, J, Strom, SP, Radu, RA, Chen, R, Gorin, MB
JournalTransl Vis Sci Technol
Date Published2022 Mar 02
KeywordsATP-Binding Cassette Transporters, Epithelial Cells, Humans, Phenotype, Retinal Pigments, Stargardt Disease

PURPOSE: Modern molecular genetics has revolutionized gene discovery, genetic diagnoses, and precision medicine yet many patients remain unable to benefit from these advances as disease-causing variants remain elusive for up to half of Mendelian genetic disorders. Patient-derived induced pluripotent stem (iPS) cells and transcriptomics were used to identify the fate of unsolved ABCA4 alleles in patients with Stargardt disease.

METHODS: Multiple independent iPS lines were generated from skin biopsies of three patients with Stargardt disease harboring a single identified pathogenic ABCA4 variant. Derived retinal pigment epithelial cells (dRPE) from a normal control and patient cells were subjected to RNA-Seq on the Novaseq6000 platform, analyzed using DESeq2 with calculation of allele specific imbalance from the pathogenic or a known linked variant. Protein analysis was performed using the automated Simple Western system.

RESULTS: Nine dRPE samples were generated, with transcriptome analysis on eight. Allele-specific expression indicated normal transcripts expressed from splice variants albeit at low levels, and missense transcripts expressed at near-normal levels. Corresponding protein was not easily detected. Patient phenotype correlation indicated missense variants expressed at high levels have more deleterious outcomes. Transcriptome analysis suggests mitochondrial membrane biodynamics and the unfolded protein response pathway may be relevant in Stargardt disease.

CONCLUSIONS: Patient-specific iPS-derived RPE cells set the stage to assess non-expressing variants in difficult-to-detect genomic regions using easily biopsied tissue.

TRANSLATIONAL RELEVANCE: This "Disease in a Dish" approach is likely to enhance the ability of patients to participate in and benefit from clinical trials while providing insights into perturbations in RPE biology.

Alternate JournalTransl Vis Sci Technol
PubMed ID35348597
PubMed Central IDPMC8976924
Grant ListR01 EY025002 / EY / NEI NIH HHS / United States
P30 EY000331 / EY / NEI NIH HHS / United States
S10 OD023469 / OD / NIH HHS / United States
R01 EY022356 / EY / NEI NIH HHS / United States
R01 EY018571 / EY / NEI NIH HHS / United States

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