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Impaired respiratory function in MELAS-induced pluripotent stem cells with high heteroplasmy levels.

Kodaira M, Hatakeyama H, Yuasa S, Seki T, Egashira T, Tohyama S, Kuroda Y, Tanaka A, Okata S, Hashimoto H, Kusumoto D, Kunitomi A, Takei M, Kashimura S, Suzuki T, Yozu G, Shimojima M, Motoda C, Hayashiji N, Saito Y, Goto Y, Fukuda K - FEBS Open Bio (2015)

Bottom Line: We successfully established iPSCs from the primary MELAS-fibroblasts carrying 77.7% of m.3243A>G heteroplasmy.MELAS-iPSC lines ranged from 3.6% to 99.4% of m.3243A>G heteroplasmy levels.The enzymatic activities of mitochondrial respiratory complexes indicated that MELAS-iPSC-derived fibroblasts with high heteroplasmy levels showed a deficiency of complex I activity but MELAS-iPSC-derived fibroblasts with low heteroplasmy levels showed normal complex I activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.

ABSTRACT
Mitochondrial diseases are heterogeneous disorders, caused by mitochondrial dysfunction. Mitochondria are not regulated solely by nuclear genomic DNA but by mitochondrial DNA. It is difficult to develop effective therapies for mitochondrial disease because of the lack of mitochondrial disease models. Mitochondrial myopathy, encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is one of the major mitochondrial diseases. The aim of this study was to generate MELAS-specific induced pluripotent stem cells (iPSCs) and to demonstrate that MELAS-iPSCs can be models for mitochondrial disease. We successfully established iPSCs from the primary MELAS-fibroblasts carrying 77.7% of m.3243A>G heteroplasmy. MELAS-iPSC lines ranged from 3.6% to 99.4% of m.3243A>G heteroplasmy levels. The enzymatic activities of mitochondrial respiratory complexes indicated that MELAS-iPSC-derived fibroblasts with high heteroplasmy levels showed a deficiency of complex I activity but MELAS-iPSC-derived fibroblasts with low heteroplasmy levels showed normal complex I activity. Our data indicate that MELAS-iPSCs can be models for MELAS but we should carefully select MELAS-iPSCs with appropriate heteroplasmy levels and respiratory functions for mitochondrial disease modeling.

No MeSH data available.


Related in: MedlinePlus

Histogram of the number of MELAS-iPSC lines with different heteroplasmy levels.
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f0010: Histogram of the number of MELAS-iPSC lines with different heteroplasmy levels.

Mentions: By quantitative real-time PCR, the m.3243A>G heteroplasmy levels in MELAS-iPSC lines ranged from 3.6% (line D1) to 99.4% (line G1), and 14 MELAS-iPSC lines had a mutant heteroplasmy level of over 80% (Fig. 2). These results indicated that MELAS-iPSC lines with a wide variety of m.3243A>G contents (<5% to >95%) could be established from the same patient. Nevertheless, those MELAS-iPSC lines showed typical iPSC morphology (Fig. 1A), differentiation capability into three different germ layer-derived tissues (Fig. 1B and C) and typical growth rates of human iPSCs (Fig. 1E). During reprogramming of the fibroblasts to iPSCs, mitochondria assumed an apparently “quiescent” state: a round-shaped morphology with poor cristae structure, less active OXPHOS, and reduced mtDNA copies [15]. Undifferentiated human iPSCs predominantly produce energy by anaerobic glycolysis, and this could explain why MELAS-iPSC lines carrying a higher proportion of m.3243A>G, even over its pathogenic threshold level, were also stably established.


Impaired respiratory function in MELAS-induced pluripotent stem cells with high heteroplasmy levels.

Kodaira M, Hatakeyama H, Yuasa S, Seki T, Egashira T, Tohyama S, Kuroda Y, Tanaka A, Okata S, Hashimoto H, Kusumoto D, Kunitomi A, Takei M, Kashimura S, Suzuki T, Yozu G, Shimojima M, Motoda C, Hayashiji N, Saito Y, Goto Y, Fukuda K - FEBS Open Bio (2015)

Histogram of the number of MELAS-iPSC lines with different heteroplasmy levels.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4383791&req=5

f0010: Histogram of the number of MELAS-iPSC lines with different heteroplasmy levels.
Mentions: By quantitative real-time PCR, the m.3243A>G heteroplasmy levels in MELAS-iPSC lines ranged from 3.6% (line D1) to 99.4% (line G1), and 14 MELAS-iPSC lines had a mutant heteroplasmy level of over 80% (Fig. 2). These results indicated that MELAS-iPSC lines with a wide variety of m.3243A>G contents (<5% to >95%) could be established from the same patient. Nevertheless, those MELAS-iPSC lines showed typical iPSC morphology (Fig. 1A), differentiation capability into three different germ layer-derived tissues (Fig. 1B and C) and typical growth rates of human iPSCs (Fig. 1E). During reprogramming of the fibroblasts to iPSCs, mitochondria assumed an apparently “quiescent” state: a round-shaped morphology with poor cristae structure, less active OXPHOS, and reduced mtDNA copies [15]. Undifferentiated human iPSCs predominantly produce energy by anaerobic glycolysis, and this could explain why MELAS-iPSC lines carrying a higher proportion of m.3243A>G, even over its pathogenic threshold level, were also stably established.

Bottom Line: We successfully established iPSCs from the primary MELAS-fibroblasts carrying 77.7% of m.3243A>G heteroplasmy.MELAS-iPSC lines ranged from 3.6% to 99.4% of m.3243A>G heteroplasmy levels.The enzymatic activities of mitochondrial respiratory complexes indicated that MELAS-iPSC-derived fibroblasts with high heteroplasmy levels showed a deficiency of complex I activity but MELAS-iPSC-derived fibroblasts with low heteroplasmy levels showed normal complex I activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.

ABSTRACT
Mitochondrial diseases are heterogeneous disorders, caused by mitochondrial dysfunction. Mitochondria are not regulated solely by nuclear genomic DNA but by mitochondrial DNA. It is difficult to develop effective therapies for mitochondrial disease because of the lack of mitochondrial disease models. Mitochondrial myopathy, encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is one of the major mitochondrial diseases. The aim of this study was to generate MELAS-specific induced pluripotent stem cells (iPSCs) and to demonstrate that MELAS-iPSCs can be models for mitochondrial disease. We successfully established iPSCs from the primary MELAS-fibroblasts carrying 77.7% of m.3243A>G heteroplasmy. MELAS-iPSC lines ranged from 3.6% to 99.4% of m.3243A>G heteroplasmy levels. The enzymatic activities of mitochondrial respiratory complexes indicated that MELAS-iPSC-derived fibroblasts with high heteroplasmy levels showed a deficiency of complex I activity but MELAS-iPSC-derived fibroblasts with low heteroplasmy levels showed normal complex I activity. Our data indicate that MELAS-iPSCs can be models for MELAS but we should carefully select MELAS-iPSCs with appropriate heteroplasmy levels and respiratory functions for mitochondrial disease modeling.

No MeSH data available.


Related in: MedlinePlus