Purpose: To expand the use of human retinal organoids from induced pluripotent stem cells (iPSCs) as an in vitro model of the retina for assessing gene therapy treatments, it is essential to establish efficient transduction. To date, targeted transduction of the photoreceptor-like cells of retinal organoids with adeno-associated virus (AAV) vectors has had varied degrees of success, which we have looked to improve in this study.
Methods: Retinal organoids were differentiated from iPSCs of healthy donors and transduced with reporter AAV containing a CAG.GFP, CAG.RFP, GRK1.GFP, or EFS.GFP transgene. Capsid variants assessed were AAV5, AAV2 7m8, AAV2 quad mutant, AAV2 Y444F, and AAV8 Y733F. At 27 days post-transduction, retinal organoids were assessed for reporter expression and viability.
Results: The short intron-less elongation factor 1 alpha (EFS) promoter provided minimal reporter expression, whereas vectors containing the CAG promoter enabled transduction in 1% to 37% of cells depending on the AAV serotype; the AAV2 quad mutant (average 19.4%) and AAV2 7m8 (16.4%) outperformed AAV5 (12%) and AAV8 Y733F (2.1%). Reporter expression from rhodopsin kinase (GRK1) promoter transgenes occurred in ∼5% of cells regardless of the serotype. Positive co-localization with recoverin-expressing cells was achieved from all GRK1 vectors and the CAG AAV2 quad mutant variant. Treatment with the AAV vectors did not influence retinal organoid viability.
Conclusions: Reliable transduction of the photoreceptor-like cells of retinal organoids can be readily achieved. When using a CAG-driven transgene, transduction of a broad range of cell types is observed, and GRK1 transgenes provide a more restricted expression profile locating to the outer layer of photoreceptor-like cells of retinal organoids.
Translational Relevance: This study expands the AAV capsid and transgene options for preclinical testing of gene therapy in iPSC-derived human retinal organoids.
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http://dx.doi.org/10.1167/tvst.11.4.3 | DOI Listing |
Acta Neuropathol Commun
January 2025
Department of Physiology and Pharmacology, Sapienza University of Rome, 00185, Rome, Italy.
The generation of retinal models from human induced pluripotent stem cells holds significant potential for advancing our understanding of retinal development, neurodegeneration, and the in vitro modeling of neurodegenerative disorders. The retina, as an accessible part of the central nervous system, offers a unique window into these processes, making it invaluable for both study and early diagnosis. This study investigates the impact of the Frontotemporal Dementia-linked IVS 10 + 16 MAPT mutation on retinal development and function using 2D and 3D retinal models derived from human induced pluripotent stem cells.
View Article and Find Full Text PDFIn Vitro Model
February 2024
iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade Nova de Lisboa, Rua Camara Pestana, 6, Lisbon, Portugal.
Purpose: Diabetic retinopathy (DR) is a complication of diabetes and a primary cause of visual impairment amongst working-age individuals. DR is a degenerative condition in which hyperglycaemia results in morphological and functional changes in certain retinal cells. Existing treatments mainly address the advanced stages of the disease, which involve vascular defects or neovascularization.
View Article and Find Full Text PDFExp Eye Res
January 2025
Institutes of Biology and Medical Sciences, Soochow University, Suzhou, 215000, China; Key Laboratory of Geriatric Diseases and Immunology, Ministry of Education, Institutes of Biology and Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, 215123, China. Electronic address:
Due to its unique physiological structure and functions, the eye has received considerable attention in the field of adeno-associated virus (AAV) gene therapy. Inherited retinal degenerative diseases, which arise from pathogenic mutations in mRNA transcripts expressed in the eye's photoreceptor cells or retinal pigment epithelium (RPE), are the most common cause of vision loss. However, current retinal gene therapy mostly involves subretinal injection of therapeutic genes, which treats a limited area, entails retinal detachment, and requires sophisticated techniques.
View Article and Find Full Text PDFCommun Med (Lond)
January 2025
Department of Human Genetics, Research Institute for Medical Innovation, Radboud University Medical Center, Nijmegen, The Netherlands.
Background: Stargardt disease type 1 (STGD1) is a progressive retinal disorder caused by bi-allelic variants in the ABCA4 gene. A recurrent variant at the exon-intron junction of exon 6, c.768G>T, causes a 35-nt elongation of exon 6 that leads to premature termination of protein synthesis.
View Article and Find Full Text PDFStem Cell Reports
January 2025
Research Center, Kobe City Eye Hospital, Kobe, Hyogo 650-0047, Japan; Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan; Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan. Electronic address:
We have previously shown that the transplantation of stem cell-derived retinal organoid (RO) sheets into animal models of end-stage retinal degeneration can lead to host-graft synaptic connectivity and restoration of vision, which was further improved using genome-edited Islet1 ROs (gROs) with a reduced number of ON-bipolar cells. However, the details of visual function restoration using this regenerative therapeutic approach have not yet been characterized. Here, we evaluated the electrophysiological properties of end-stage rd1 retinas after transplantation (TP-rd1) and compared them with those of wild-type (WT) retinas using multi-electrode arrays.
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