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Qin Wan, Mitra Farnoodian, Nathan Hotaling, Aman George, Kiyoharu miyagishima, Roba Dejene, Tyler Pfister, Arvydas Maminishkis, Brian Patrick Brooks, Sheldon S Miller, Kapil Bharti; Altered electrical responses in iPSC-RPE derived from distinct genetic eye diseases. Invest. Ophthalmol. Vis. Sci. 2019;60(9):6396.
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© ARVO (1962-2015); The Authors (2016-present)
The retinal pigment epithelium (RPE) is essential for the homeostasis of retinal photoreceptors and the preservation of vision. The damage or function abnormality of RPE cells is implicated in many genetic eye diseases, contributing to the progressive loss of photoreceptors and vision. In the present study, we assess the resting and stimulated electrical property changes in human iPSC derived RPE (iPSC-RPE) generated from patients with various genetic eye diseases, in pursuit of standard physiological assays that could efficiently evaluate iPSC-RPE function in disease conditions or determine its potency prior to a cell therapy.
iPSC-RPE generated from healthy control or patients with different genetic eye diseases were grown on semi-permeable transwells to reach a confluent monolayer. For electrical recording, calomel electrodes in series with agar bridges were used to measure the transepithelial potential (TEP). The tissue resistance (Rt) was obtained by passing current across the tissue and measuring the resultant changes in TEP. To evaluate the iPSC-RPE physiological function, two physiologically relevant stimuli, 1mM low-K+ or 100mM ATP was applied to the apical bath.
As compared to the control, iPSC-RPE derived from Best disease patient showed decreased resting TEP with the same range Rt, ATP-induced response was reduced while low-K+ response remained unchanged. In contrast, iPSC-RPE derived from ocular albinism, with two types of OCA2 mutations, displayed similar resting TEP and Rt as the control, but decreased low-K+ response and enhanced ATP response. In iPSC-RPE derived from Stargardt macular degeneration with ABCA4 mutation in RPE cells, the resting TEP and Rt were decreased accompanied with suppression of both low-K+ and ATP responses. No noticeable electrical changes were observed in iPSC-RPE derived from the patient with Late-onset retinal denegation.
iPSC-RPE demonstrates distinct electrical property alterations in different genetic eye diseases, implicating electrophysiology assay as a valuable approach to assess RPE function in disease condition. Physiologically relevant low-K+ and ATP stimuli produce notable electrical changes in various disease conditions thus can be used as standard benchmark to evaluate various disease cellular endophenotypes and to determine iPSC-RPE monolayer potency prior to transplantation in patients with retinal degenerative diseases.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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