Human stem cell aging: do mitochondrial DNA mutations have a causal role?

Authors

  • Holly L. Baines,

    1. Centre for Brain Ageing and Vitality, Institute for Ageing and Health, The Medical School, Newcastle upon Tyne, UK
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  • Douglass M. Turnbull,

    1. Centre for Brain Ageing and Vitality, Institute for Ageing and Health, The Medical School, Newcastle upon Tyne, UK
    2. Wellcome Trust centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
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  • Laura C. Greaves

    Corresponding author
    1. Centre for Brain Ageing and Vitality, Institute for Ageing and Health, The Medical School, Newcastle upon Tyne, UK
    • Correspondence

      Dr Laura C Greaves, Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK. Tel.: +44 1912226291; fax: +44 1912086662;

      e-mail: laura.greaves@ncl.ac.uk

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Summary

A decline in the replicative and regenerative capacity of adult stem cell populations is a major contributor to the aging process. Mitochondrial DNA (mtDNA) mutations clonally expand with age in human stem cell compartments including the colon, small intestine, and stomach, and result in respiratory chain deficiency. Studies in a mouse model with high levels of mtDNA mutations due to a defect in the proofreading domain of the mtDNA polymerase γ (mtDNA mutator mice) have established causal relationships between the accumulation of mtDNA point mutations, stem cell dysfunction, and premature aging. These mtDNA mutator mice have also highlighted that the consequences of mtDNA mutations upon stem cells vary depending on the tissue. In this review, we present evidence that these studies in mice are relevant to normal human stem cell aging and we explore different hypotheses to explain the tissue-specific consequences of mtDNA mutations. In addition, we emphasize the need for a comprehensive analysis of mtDNA mutations and their effects on cellular function in different aging human stem cell populations.

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