Quiescent adult neural stem cells are exceptionally sensitive to cosmic radiation.
Generation of new neurons in the adult brain, a process that is likely to be essential for learning, memory, and mood regulation, is impaired by radiation. Therefore, radiation exposure might have not only such previously expected consequences as increased probability of developing cancer, but might also impair cognitive function and emotional stability. Radiation exposure is encountered in settings ranging from cancer therapy to space travel; evaluating the neurogenic risks of radiation requires identifying the at-risk populations of stem and progenitor cells in the adult brain. Here we have used a novel reporter mouse line to find that early neural progenitors are selectively affected by conditions simulating the space radiation environment. This is reflected both in a decrease in the number of these progenitors in the neurogenic regions and in an increase in the number of dying cells in these regions. Unexpectedly, we found that quiescent neural stem cells, rather than their rapidly dividing progeny, are most sensitive to radiation. Since these stem cells are responsible for adult neurogenesis, their death would have a profound impact on the production of new neurons in the irradiated adult brain. Our finding raises an important concern about cognitive and emotional risks associated with radiation exposure.
Encinas
Juan M
JM
Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
Vazquez
Marcelo E
ME
Switzer
Robert C
RC
Chamberland
Dennis W
DW
Nick
Harry
H
Levine
Howard G
HG
Scarpa
Philip J
PJ
Enikolopov
Grigori
G
Steindler
Dennis A
DA
D053687:Adult Stem Cells / Q000528:radiation effects*; D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D002454:Cell Differentiation / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects*; D003359:Cosmic Radiation; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D007381:Intermediate Filament Proteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D064231:Nestin
C485182:Cyan Fluorescent Protein; D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; C577485:Nes protein, mouse; D064231:Nestin; D049452:Green Fluorescent Proteins; D053148:Caspase 3; D001973:Bromodeoxyuridine