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Nature. 2015 Jul 9;523(7559):226-30. doi: 10.1038/nature14582. Epub 2015 Jun 22.

Hypoxia fate mapping identifies cycling cardiomyocytes in the adult heart.

Author information

1
1] Department of Internal Medicine, Division of Cardiology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA [2] Life Science Center, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan.
2
Department of Internal Medicine, Division of Cardiology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
3
Departments of Physiology and Developmental Biology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
4
1] Department of Internal Medicine, Division of Cardiology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA [2] Department of Medicine, VA North Texas Health Care System, 4600 South Lancaster Road, Dallas, Texas 75216, USA.
5
1] Department of Molecular Biology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA [2] Department of Pathology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
6
Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
7
McDermott Center for Human Growth and Development, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
8
1] Department of Internal Medicine, Division of Cardiology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA [2] Hamon Center for Regenerative Science and Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.

Abstract

Although the adult mammalian heart is incapable of meaningful functional recovery following substantial cardiomyocyte loss, it is now clear that modest cardiomyocyte turnover occurs in adult mouse and human hearts, mediated primarily by proliferation of pre-existing cardiomyocytes. However, fate mapping of these cycling cardiomyocytes has not been possible thus far owing to the lack of identifiable genetic markers. In several organs, stem or progenitor cells reside in relatively hypoxic microenvironments where the stabilization of the hypoxia-inducible factor 1 alpha (Hif-1α) subunit is critical for their maintenance and function. Here we report fate mapping of hypoxic cells and their progenies by generating a transgenic mouse expressing a chimaeric protein in which the oxygen-dependent degradation (ODD) domain of Hif-1α is fused to the tamoxifen-inducible CreERT2 recombinase. In mice bearing the creERT2-ODD transgene driven by either the ubiquitous CAG promoter or the cardiomyocyte-specific α myosin heavy chain promoter, we identify a rare population of hypoxic cardiomyocytes that display characteristics of proliferative neonatal cardiomyocytes, such as smaller size, mononucleation and lower oxidative DNA damage. Notably, these hypoxic cardiomyocytes contributed widely to new cardiomyocyte formation in the adult heart. These results indicate that hypoxia signalling is an important hallmark of cycling cardiomyocytes, and suggest that hypoxia fate mapping can be a powerful tool for identifying cycling cells in adult mammals.

PMID:
26098368
DOI:
10.1038/nature14582
[Indexed for MEDLINE]

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