Akt Suppression of TGFβ Signaling Contributes to the Maintenance of Vascular Identity in Embryonic Stem Cell-Derived Endothelial Cells

Authors

  • Edo Israely,

    1. Department of Genetic Medicine, Ansary Stem Cell Institute, Howard Hughes Medical Institute, Weill Cornell Medical College, New York, New York, USA
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  • Michael Ginsberg,

    1. Angiocrine Bioscience, Inc., New York, New York, USA
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  • Daniel Nolan,

    1. Angiocrine Bioscience, Inc., New York, New York, USA
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  • Bi-Sen Ding,

    1. Department of Genetic Medicine, Ansary Stem Cell Institute, Howard Hughes Medical Institute, Weill Cornell Medical College, New York, New York, USA
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  • Daylon James,

    1. Department of Genetic Medicine, Ansary Stem Cell Institute, Howard Hughes Medical Institute, Weill Cornell Medical College, New York, New York, USA
    2. Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medical College, New York, New York, USA
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  • Olivier Elemento,

    1. HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Cornell Medical College, New York, New York, USA
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  • Shahin Rafii,

    1. Department of Genetic Medicine, Ansary Stem Cell Institute, Howard Hughes Medical Institute, Weill Cornell Medical College, New York, New York, USA
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  • Sina Y. Rabbany

    Corresponding author
    1. Department of Genetic Medicine, Ansary Stem Cell Institute, Howard Hughes Medical Institute, Weill Cornell Medical College, New York, New York, USA
    2. Bioengineering Program, Hofstra University, Hempstead, New York, New York, USA
    • Correspondence: Sina Y. Rabbany, Ph.D., 1300 York Avenue, Room A-869, New York, New York 10065, USA. Telephone: +1–212-746–7014; Fax: +1–212-746–8481; e-mail: sir2007@med.cornell.edu

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Abstract

The ability to generate and maintain stable in vitro cultures of mouse endothelial cells (ECs) has great potential for genetic dissection of the numerous pathologies involving vascular dysfunction as well as therapeutic applications. However, previous efforts at achieving sustained cultures of primary stable murine vascular cells have fallen short, and the cellular requirements for EC maintenance in vitro remain undefined. In this study, we have generated vascular ECs from mouse embryonic stem (ES) cells and show that active Akt is essential to their survival and propagation as homogeneous monolayers in vitro. These cells harbor the phenotypical, biochemical, and functional characteristics of ECs and expand throughout long-term cultures, while maintaining their angiogenic capacity. Moreover, Akt-transduced embryonic ECs form functional perfused vessels in vivo that anastomose with host blood vessels. We provide evidence for a novel function of Akt in stabilizing EC identity, whereby the activated form of the protein protects mouse ES cell-derived ECs from TGFβ-mediated transdifferentiation by downregulating SMAD3. These findings identify a role for Akt in regulating the developmental potential of ES cell-derived ECs and demonstrate that active Akt maintains endothelial identity in embryonic ECs by interfering with active TGFβ-mediated processes that would ordinarily usher these cells to alternate fates. Stem Cells 2014;32:177–190

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