• Open Access

Cellular lifespan and senescence signaling in embryonic stem cells

Authors

  • Takumi Miura,

    1. Stem Cell Biology Unit and
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  • Mark P. Mattson,

    1. Cellular and Molecular Neurosciences Section, Laboratory of Neurosciences, National Institute on Aging, Gerontology Research Center, Baltimore, MD 21224, USA
    2. Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
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  • Mahendra S. Rao

    Corresponding author
    1. Stem Cell Biology Unit and
    2. Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
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Dr M. S. Rao, Stem Cell Biology Unit, Laboratory of Neurosciences, National Institute on Aging, GRC, 5600 Nathan Shock Drive, Room 4E01, Baltimore, MD 21224, USA. Tel.: +410 558 8204; fax: +410 558 8323; e-mail: raomah@grc.nia.nih.gov

Summary

Most mammalian cells when placed in culture will undergo a limited number of cell divisions before entering an unresponsive non-proliferating state termed senescence. However, several pathways that are activated singly or in concert can allow cells to bypass senescence at least for limited periods. These include the telomerase pathway required to maintain telomere ends, the p53 and Rb pathways required to direct senescence in response to DNA damage, telomere shortening and mitogenic signals, and the insulin-like growth factor – Akt pathway that may regulate lifespan and cell proliferation. In this review, we summarize recent findings related to these pathways in embryonic stem (ES) cells and suggest that ES cells are immortal because these pathways are tightly regulated.

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