5-Aminoimidazole-4-carboxyamide Ribonucleoside Induces G1/S Arrest and Nanog Downregulation via p53 and Enhances Erythroid Differentiation§

Authors

  • Hee-Don Chae,

    1. Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana
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  • Man-Ryul Lee,

    1. Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana
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  • Hal E. Broxmeyer

    Corresponding author
    1. Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana
    • Department of Microbiology and Immunology, Indiana University School of Medicine, 950 West Walnut Street, R2-302 Indianapolis, Indiana 46202, USA
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    • Telephone: 317-274-7510; Fax: 317-274-7592


  • Author contributions: H.-D.C.: conception and design, collection and/or assembly of data, data analysis and interpretation, and manuscript writing; M.R.L.: collection of data.; H.E.B.: financial support, data analysis and interpretation, and manuscript writing.

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

  • §

    First published online in STEM CELLSEXPRESS November 10, 2011.

Abstract

Molecular mechanisms of how energy metabolism affects embryonic stem cell (ESC) pluripotency remain unclear. AMP-activated protein kinase (AMPK), a key regulator for controlling energy metabolism, is activated in response to ATP-exhausting stress. We investigated whether cellular energy homeostasis is associated with maintenance of self-renewal and pluripotency in mouse ESCs (mESCs) by using 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) as an activator of AMPK. We demonstrate that AICAR treatment activates the p53/p21 pathway and markedly inhibits proliferation of R1 mESCs by inducing G1/S-phase cell cycle arrest, without influencing apoptosis. Treatment with AICAR also significantly reduces pluripotent stem cell markers, Nanog and stage-specific embryonic antigen-1, in the presence of leukemia inhibitory factor, without affecting expression of Oct4. H9 human ESCs also responded to AICAR with induction of p53 activation and repression of Nanog expression. AICAR reduced Nanog mRNA levels in mESCs transiently, an effect not due to expression of miR-134 which can suppress Nanog expression. AICAR induced Nanog degradation, an effect inhibited by MG132, a proteasome inhibitor. Although AICAR reduced embryoid body formation from mESCs, it increased expression levels of erythroid cell lineage markers (Ter119, GATA1, Klf1, Hbb-b, and Hbb-bh1). Although erythroid differentiation was enhanced by AICAR, endothelial lineage populations were remarkably reduced in AICAR-treated cells. Our results suggest that energy metabolism regulated by AMPK activity may control the balance of self-renewal and differentiation of ESCs. STEM CELLS 2012; 30:140–149.

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