Protein O-GlcNAcylation Is a Novel Cytoprotective Signal in Cardiac Stem Cells§

Authors

  • Ayesha Zafir,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
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  • Ryan Readnower,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
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  • Bethany W. Long,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
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  • James McCracken,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
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  • Allison Aird,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
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  • Alejandro Alvarez,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
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  • Timothy D. Cummins,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
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  • Qianhong Li,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
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  • Bradford G. Hill,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
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  • Aruni Bhatnagar,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
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  • Sumanth D. Prabhu,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
    2. Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama, USA
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  • Roberto Bolli,

    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
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  • Steven P. Jones

    Corresponding author
    1. Department of Medicine, Division of Cardiovascular Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky, USA
    • Institute of Molecular Cardiology, University of Louisville, 580 South Preston Street—321F, Baxter II—321F, Louisville, Kentucky 40202, USA
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    • Telephone: (502) 852-2460; Fax: (502) 852-8070


  • A.Z.: conception and design, collection and assembly of data, data analysis and interpretation, manuscript writing, and final approval of manuscript; R.R., B.W.L., A.A., and A.A.: collection and/or assembly of data and data analysis and interpretation; J.M. and T.D.C.: collection and/or assembly of data, data analysis and interpretation, and final approval of manuscript; Q.L.: provision of study material; B.G.H.: administrative support, data analysis and interpretation, manuscript writing, and final approval of manuscript; A.B.: financial support, administrative support, manuscript writing, and final approval of manuscript; S.D.P.: financial support and administrative support; R.B.: conception and design, financial support, administrative support, provision of study material, and final approval of manuscript, S.P.J.: conception and design, financial support, administrative support, data analysis and interpretation, manuscript writing, and final approval of manuscript.

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

  • §

    First published online in STEM CELLS EXPRESS January 17, 2013.

Abstract

Clinical trials demonstrate the regenerative potential of cardiac stem cell (CSC) therapy in the postinfarcted heart. Despite these encouraging preliminary clinical findings, the basic biology of these cells remains largely unexplored. The principal requirement for cell transplantation is to effectively prime them for survival within the unfavorable environment of the infarcted myocardium. In the adult mammalian heart, the β-O-linkage of N-acetylglucosamine (i.e., O-GlcNAc) to proteins is a unique post-translational modification that confers cardioprotection from various otherwise lethal stressors. It is not known whether this signaling system exists in CSCs. In this study, we demonstrate that protein O-GlcNAcylation is an inducible stress response in adult murine Sca-1+/lin CSCs and exerts an essential prosurvival role. Posthypoxic CSCs responded by time-dependently increasing protein O-GlcNAcylation upon reoxygenation. We used pharmacological interventions for loss- and gain-of-function, that is, enzymatic inhibition of O-GlcNAc transferase (OGT) (adds the O-GlcNAc modification to proteins) by TT04, or inhibition of OGA (removes O-GlcNAc) by thiamet-G (ThG). Reduction in the O-GlcNAc signal (via TT04, or OGT gene deletion using Cre-mediated recombination) significantly sensitized CSCs to posthypoxic injury, whereas augmenting O-GlcNAc levels (via ThG) enhanced cell survival. Diminished O-GlcNAc levels render CSCs more susceptible to the onset of posthypoxic apoptotic processes via elevated poly(ADP-ribose) polymerase cleavage due to enhanced caspase-3/7 activation, whereas promoting O-GlcNAcylation can serve as a pre-emptive antiapoptotic signal regulating the survival of CSCs. Thus, we report the primary demonstration of protein O-GlcNAcylation as an important prosurvival signal in CSCs, which could enhance CSC survival prior to in vivo autologous transfer. STEM CELLS 2013;31:765–775

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