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Kohei Homma, Toshio Narimatsu, Kazuo Tsubota, Hideyuki Okano, Yoko Ozawa; Analysis of retinal disease mechanism by using MELAS patient-derived induced pluripotent stem cell lines. Invest. Ophthalmol. Vis. Sci. 2020;61(7):3540.
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© ARVO (1962-2015); The Authors (2016-present)
Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is one of the mitochondrial diseases, which are caused by mitochondria DNA mutation. Although several attempts to rescue the phenotype have been made, the effective treatments were limited. To analyze the MELAS disease mechanisms, we utilized induced pluripotent stem cell (iPSC) lines derived from MELAS patients. This study investigates cellular functions and gene expression in MELAS iPSCs and iPSCs -derived retinal pigment epithelium (RPE).
Control hiPSCs (454E2, 201B7) and hiPSCs derived from patients with mitochondria DNA (mtDNA)-mutation, A3243G (MELAS-iPSCs) were cultured for the reporter knock-in experiment. Established iPSCs were treated with several drugs or nutrients. These cell lines were differentiated into retinal organoids by the three-dimensional retinal differentiation culture. The study adhered to the tenets of the Declaration of Helsinki was approved by the Ethics Committee of Keio University School of Medicine (Tokyo, Japan; 20080016).
We confirmed the mutation of mtDNA in MELAS hiPSCs by qPCR. The mutation rates were rather maintained thorough the maintenance culture. The oxygen-consumption rate (OCR) was decreased in MELAS iPSCs, while the extracellular acidification rate (ECAR) was unaffected. Also, the low concentration of 2-deoxy-glucose (2DG), which inhibits glycolysis, decreased cell number of MELAS iPSCs during maintenance culture. In 2DG-treated MELAS iPSCs, cleaved caspase 3 positive cells were increased. After several drug screening of 2DG-treated MELAS iPSCs, we identified taurine may have some effect on the 2DG-induced apoptosis in MELAS iPSCs. After the retinal differentiation culture, we observed rod photoreceptors and RPE from the control and MELAS iPSCs. RPE derived from iPSCs were stained with RPE markers, though the markers were found only patchy and not constant in MELAS RPE. In MELAS RPE, gene expressions of glucose transporters, lactate transporters, are decreased. The OCR and ECAR were decreased in MELAS RPE.
MELAS patient-derived hiPSCs and RPE were established to analyze retinal degeneration in vitro. Taurine rescued the function of mitochondria in MELAS iPSCs. Differentiated photoreceptors and RPE from MELAS iPSC could be used to analyze the effects of drugs for the MELAS treatment.
This is a 2020 ARVO Annual Meeting abstract.
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