Disease-Causing Mitochondrial Heteroplasmy Segregated Within Induced Pluripotent Stem Cell Clones Derived from a Patient with MELAS§

Authors

  • Clifford D.L. Folmes,

    1. Department of Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
    2. Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
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  • Almudena Martinez-Fernandez,

    1. Department of Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
    2. Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
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  • Ester Perales-Clemente,

    1. Department of Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
    2. Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
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  • Xing Li,

    1. Department of Health Sciences Research, Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota
    2. Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
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  • Amber Mcdonald,

    1. Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
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  • Devin Oglesbee,

    1. Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
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  • Sybil C. Hrstka,

    1. Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
    2. Department of Medicine, Division of General Internal Medicine, Mayo Clinic, Rochester, Minnesota
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  • Carmen Perez-Terzic,

    1. Department of Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
    2. Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
    3. Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota
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  • Andre Terzic,

    1. Department of Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
    2. Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
    3. Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
    4. Department of Medical Genetics, Mayo Clinic, Rochester, Minnesota, USA
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  • Timothy J. Nelson

    Corresponding author
    1. Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
    2. Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota
    3. Department of Medicine, Division of General Internal Medicine, Mayo Clinic, Rochester, Minnesota
    4. Transplant Center, Mayo Clinic, Rochester, Minnesota
    • Department of Medicine and Transplant Center, Mayo Clinic, Stabile 5-42, 200 First St., S.W., Rochester, MN 55905, USA
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    • Telephone: 507-538-7515; Fax: 507-266-9936


  • Author contributions: A.M.-F., C.D.L.F., and E.P.-C.: conception and design, collection and/or assembly of data, data analysis and interpretation, manuscript writing; C.P.-T., S.H., and A.M.: collection and/or assembly of data; X.L.: data analysis and interpretation; D.O.: provision of study materials or patients; A.T. and T.J.N.: conception and design, data analysis and interpretation, manuscript writing, final approval of manuscript. C.D.L.F., A.M.-F., and E.P.-C. contributed equally to this article.

  • Disclosure of potential conflicts of interest is found at the end of this article.

  • §

    first published online in STEM CELLS EXPRESS April 3, 2013.

Abstract

Mitochondrial diseases display pathological phenotypes according to the mixture of mutant versus wild-type mitochondrial DNA (mtDNA), known as heteroplasmy. We herein examined the impact of nuclear reprogramming and clonal isolation of induced pluripotent stem cells (iPSC) on mitochondrial heteroplasmy. Patient-derived dermal fibroblasts with a prototypical mitochondrial deficiency diagnosed as mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) demonstrated mitochondrial dysfunction with reduced oxidative reserve due to heteroplasmy at position G13513A in the ND5 subunit of complex I. Bioengineered iPSC clones acquired pluripotency with multilineage differentiation capacity and demonstrated reduction in mitochondrial density and oxygen consumption distinguishing them from the somatic source. Consistent with the cellular mosaicism of the original patient-derived fibroblasts, the MELAS-iPSC clones contained a similar range of mtDNA heteroplasmy of the disease-causing mutation with identical profiles in the remaining mtDNA. High-heteroplasmy iPSC clones were used to demonstrate that extended stem cell passaging was sufficient to purge mutant mtDNA, resulting in isogenic iPSC subclones with various degrees of disease-causing genotypes. On comparative differentiation of iPSC clones, improved cardiogenic yield was associated with iPSC clones containing lower heteroplasmy compared with isogenic clones with high heteroplasmy. Thus, mtDNA heteroplasmic segregation within patient-derived stem cell lines enables direct comparison of genotype/phenotype relationships in progenitor cells and lineage-restricted progeny, and indicates that cell fate decisions are regulated as a function of mtDNA mutation load. The novel nuclear reprogramming-based model system introduces a disease-in-a-dish tool to examine the impact of mutant genotypes for MELAS patients in bioengineered tissues and a cellular probe for molecular features of individual mitochondrial diseases. STEM Cells2013;31:1298–1308

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