• Open Access

FGF2 and Insulin Signaling Converge to Regulate Cyclin D Expression in Multipotent Neural Stem Cells

Authors

  • Adedamola Adepoju,

    1. National Institute for Neurological Disorders and Stroke, Maryland, USA
    2. University of Massachusetts School of Medicine, Massachusetts, USA
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  • Nicola Micali,

    1. National Institute for Neurological Disorders and Stroke, Maryland, USA
    2. Lieber Institute for Brain Development, Baltimore, Maryland, USA
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  • Kazuya Ogawa,

    1. National Institute for Neurological Disorders and Stroke, Maryland, USA
    2. Lieber Institute for Brain Development, Baltimore, Maryland, USA
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  • Daniel J. Hoeppner,

    1. National Institute for Neurological Disorders and Stroke, Maryland, USA
    2. Lieber Institute for Brain Development, Baltimore, Maryland, USA
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  • Ronald D.G. McKay

    Corresponding author
    1. National Institute for Neurological Disorders and Stroke, Maryland, USA
    2. Lieber Institute for Brain Development, Baltimore, Maryland, USA
    • Correspondence: Ronald McKay, Ph.D., Lieber Institute for Brain Development, 855 N Wolfe Street, Baltimore, Maryland 21205, USA. Telephone: 410-955-1000; Fax: 410-955-1044; e-mail: ronald.mckay@libd.org; or Daniel Hoeppner, Ph.D., Lieber Institute for Brain Development, 855 N Wolfe Street, Baltimore, Maryland 21205, USA. Telephone: 410–955-1000; Fax: 410–955-1044; e-mail: daniel.hoeppner@libd.org

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Abstract

The ex vivo expansion of stem cells is making major contribution to biomedical research. The multipotent nature of neural precursors acutely isolated from the developing central nervous system has been established in a series of studies. Understanding the mechanisms regulating cell expansion in tissue culture would support their expanded use either in cell therapies or to define disease mechanisms. Basic fibroblast growth factor (FGF2) and insulin, ligands for tyrosine kinase receptors, are sufficient to sustain neural stem cells (NSCs) in culture. Interestingly, real-time imaging shows that these cells become multipotent every time they are passaged. Here, we analyze the role of FGF2 and insulin in the brief period when multipotent cells are present. FGF2 signaling results in the phosphorylation of Erk1/2, and activation of c-Fos and c-Jun that lead to elevated cyclin D mRNA levels. Insulin signals through the PI3k/Akt pathway to regulate cyclins at the post-transcriptional level. This precise Boolean regulation extends our understanding of the proliferation of multipotent NSCs and provides a basis for further analysis of proliferation control in the cell states defined by real-time mapping of the cell lineages that form the central nervous system. Stem Cells 2014;32:770–778

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