Abstract
Purpose :
Ocular Albinism type 1 (OA) is an X-linked disease caused by mutations in the GPR143 and GNAI3 genes. Currently, there is no experimental human model of this yet untreatable disease. To address this issue, we developed an induced pluripotent stem cell (iPSCs) line from a patient with OA. We then compared the human retinal pigment epithelial (hRPE) cells differentiated from the patient’s iPSCs with hRPE cells differentiated from normal H9 human embryonic stem cells (hESCs).
Methods :
A skin biopsy was collected from an OA patient who has a mutation in the GPR143 gene and skin fibroblasts were reprogrammed into iPSCs using a Sendai virus-based method. Pluripotency and absence of chromosomal abnormalities in the clones were confirmed by flow cytometry, immunofluorescence, and karyotyping. iPSCs were differentiated into hRPE cells using a 14 days protocol. The morphology, phenotype and GPR143 expression of iPSCs-derived hRPE cells was compared by immunofluorescence, Western blot, RT-qPCR and transmission electron microscopy, with those of hRPE cells derived from H9 hESCs using the same differentiation protocol.
Results :
iPSCs generated from the patient's skin show normal karyotype, high expression of stem cell markers OCT4, NANOG, TRA1-60, SSEA4, and a trilineage differentiation capability similar to H9 hESCs. hRPE cells derived from the patient’s iPSCs are comparable with hRPE cells derived from H9 hESCs in terms of phenotype, morphology and function, but show a drastic reduction in GPR143 expression and abnormalities in the size, shape and number of melanosomes, consistent with the typical phenotype of RPE cells from GPR143 knock-out mice.
Conclusions :
hRPE cells differentiated from an OA patient’s iPSCs recapitulate key features of RPE cells derived from GPR143 knock-out mice. This first human in-vitro modeling of OA is an important step forward for gaining more knowledge on the physiopathology of this disease.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.