Tie2+ Bone Marrow Endothelial Cells Regulate Hematopoietic Stem Cell Regeneration Following Radiation Injury§

Authors

  • Phuong L. Doan,

    1. Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • J. Lauren Russell,

    1. Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • Heather A. Himburg,

    1. Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • Katherine Helms,

    1. Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • Jeffrey R. Harris,

    1. Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • Joseph Lucas,

    1. Institute for Genome Sciences and Policy, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • Kirsten C. Holshausen,

    1. Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • Sarah K. Meadows,

    1. Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • Pamela Daher,

    1. Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • Laura B. Jeffords,

    1. Department of Radiation Oncology, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • Nelson J. Chao,

    1. Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke University, Durham, North Carolina, USA
    2. Department of Immunology, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • David G. Kirsch,

    1. Department of Radiation Oncology, Duke University, Durham, North Carolina, USA
    2. Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
    Search for more papers by this author
  • John P. Chute

    Corresponding author
    1. Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke University, Durham, North Carolina, USA
    2. Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
    • Professor of Medicine, Pharmacology and Cancer Biology, Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke University, Durham, North Carolina 27710, USA
    Search for more papers by this author
    • Tel: 919-668-4706; Fax: 919-668-1091


  • Author contributions: P.L.D.: collection and assembly of data, data analysis and interpretation, and manuscript writing; J.L.R.: collection and/or assembly of data and data analysis and interpretation; H.A.H., K.H., J.R.H, K.C.H., and S.K.M.: collection and/or assembly of data; J.L.: data analysis and interpretation; L.B.J.: provision of study materials and collection and assembly of data; N.J.C. and D.G.K.: data analysis and interpretation, manuscript writing, and final approval of manuscript; J.P.C.: conception and design, 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 CELLSEXPRESS November 6, 2012.

Abstract

Hematopoietic stem cells (HSCs) reside in proximity to bone marrow endothelial cells (BM ECs) and maintenance of the HSC pool is dependent upon EC-mediated c-kit signaling. Here, we used genetic models to determine whether radioprotection of BM ECs could facilitate hematopoietic regeneration following radiation-induced myelosuppression. We developed mice bearing deletion of the proapoptotic proteins, BAK and BAX, in Tie2+ ECs and HSCs (Tie2Bak/BaxFl/− mice) and compared their hematopoietic recovery following total body irradiation (TBI) with mice which retained Bax in Tie2+ cells. Mice bearing deletion of Bak and Bax in Tie2+ cells demonstrated protection of BM HSCs, preserved BM vasculature, and 100% survival following lethal dose TBI. In contrast, mice that retained Bax expression in Tie2+ cells demonstrated depletion of BM HSCs, disrupted BM vasculature, and 10% survival post-TBI. In a complementary study, VEcadherinBak/BaxFl/− mice, which lack Bak and Bax in VEcadherin+ ECs, also demonstrated increased recovery of BM stem/progenitor cells following TBI compared to mice which retained Bax in VEcadherin+ ECs. Importantly, chimeric mice that lacked Bak and Bax in HSCs but retained Bak and Bax in BM ECs displayed significantly decreased HSC content and survival following TBI compared to mice lacking Bak and Bax in both HSCs and BM ECs. These data suggest that the hematopoietic response to ionizing radiation is dependent upon HSC-autonomous responses but is regulated by BM EC-mediated mechanisms. Therefore, BM ECs may be therapeutically targeted as a means to augment hematopoietic reconstitution following myelosuppression. STEM CELLS2013;31:327–337

Ancillary