Open AccessTie2 + Bone Marrow Endothelial Cells Regulate Hematopoietic Stem Cell Regeneration Following Radiation Injury
Author(s) -
Doan Phuong L.,
Russell J. Lauren,
Himburg Heather A.,
Helms Katherine,
Harris Jeffrey R.,
Lucas Joseph,
Holshausen Kirsten C.,
Meadows Sarah K.,
Daher Pamela,
Jeffords Laura B.,
Chao Nelson J.,
Kirsch David G.,
Chute John P.
Publication year - 2013
Publication title -
stem cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.159
H-Index - 229
eISSN - 1549-4918
pISSN - 1066-5099
DOI - 10.1002/stem.1275
Subject(s) - haematopoiesis , bone marrow , stem cell , biology , progenitor cell , hematopoietic stem cell , cancer research , regeneration (biology) , microbiology and biotechnology , endothelial stem cell , total body irradiation , immunology , in vitro , chemotherapy , biochemistry , genetics , cyclophosphamide
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/Bax Fl/− 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/Bax Fl/− 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. S TEM C ELLS 2013;31:327–337