• Open Access

Hhex and Cer1 Mediate the Sox17 Pathway for Cardiac Mesoderm Formation in Embryonic Stem Cells

Authors

  • Yu Liu,

    1. Center for Cardiovascular Development, Baylor College of Medicine, Houston, Texas, USA
    2. Institute for Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas, USA
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  • Ruri Kaneda,

    1. Center for Cardiovascular Development, Baylor College of Medicine, Houston, Texas, USA
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  • Thomas W. Leja,

    1. British Heart Foundation Centre of Research Excellence, Imperial College London, London, United Kingdom
    2. National Heart and Lung Institute, Imperial College London, London, United Kingdom
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  • Tatiana Subkhankulova,

    1. British Heart Foundation Centre of Research Excellence, Imperial College London, London, United Kingdom
    2. National Heart and Lung Institute, Imperial College London, London, United Kingdom
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  • Oleg Tolmachov,

    1. British Heart Foundation Centre of Research Excellence, Imperial College London, London, United Kingdom
    2. National Heart and Lung Institute, Imperial College London, London, United Kingdom
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  • Gabriella Minchiotti,

    1. Institute of Genetics and Biophysics “Adriano Buzzati Traverso,” CNR, Naples, Italy
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  • Robert J. Schwartz,

    1. Center for Cardiovascular Development, Baylor College of Medicine, Houston, Texas, USA
    2. Institute for Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas, USA
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  • Mauricio Barahona,

    1. British Heart Foundation Centre of Research Excellence, Imperial College London, London, United Kingdom
    2. Department of Mathematics, Imperial College London, London, United Kingdom
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  • Michael D. Schneider

    Corresponding author
    1. Center for Cardiovascular Development, Baylor College of Medicine, Houston, Texas, USA
    2. Institute for Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas, USA
    3. British Heart Foundation Centre of Research Excellence, Imperial College London, London, United Kingdom
    4. National Heart and Lung Institute, Imperial College London, London, United Kingdom
    • Correspondence: Michael D. Schneider, M.D., British Heart Foundation Centre for Research Excellence, Imperial College London, Imperial Centre for Translational and Experimental Medicine, Room 336, Du Cane Road, London W12 0NN, U.K. Telephone: 11–44-20–7594-3027; Fax: 11–44-20–7594-3015; e-mail: m.d.schneider@imperial.ac.uk

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Abstract

Cardiac muscle differentiation in vivo is guided by sequential growth factor signals, including endoderm-derived diffusible factors, impinging on cardiogenic genes in the developing mesoderm. Previously, by RNA interference in AB2.2 mouse embryonic stem cells (mESCs), we identified the endodermal transcription factor Sox17 as essential for Mesp1 induction in primitive mesoderm and subsequent cardiac muscle differentiation. However, downstream effectors of Sox17 remained to be proven functionally. In this study, we used genome-wide profiling of Sox17-dependent genes in AB2.2 cells, RNA interference, chromatin immunoprecipitation, and luciferase reporter genes to dissect this pathway. Sox17 was required not only for Hhex (a second endodermal transcription factor) but also for Cer1, a growth factor inhibitor from endoderm that, like Hhex, controls mesoderm patterning in Xenopus toward a cardiac fate. Suppressing Hhex or Cer1 blocked cardiac myogenesis, although at a later stage than induction of Mesp1/2. Hhex was required but not sufficient for Cer1 expression. Over-expression of Sox17 induced endogenous Cer1 and sequence-specific transcription of a Cer1 reporter gene. Forced expression of Cer1 was sufficient to rescue cardiac differentiation in Hhex-deficient cells. Thus, Hhex and Cer1 are indispensable components of the Sox17 pathway for cardiopoiesis in mESCs, acting at a stage downstream from Mesp1/2. Stem Cells 2014;32:1515–1526

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