Funding Status:
Completed - Task completed and produced a deliverable
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Procurement Mechanism(s):
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Aims:
- In Aim 1, using behavioral tests with which we have recently published (delayed non-match to pattern radial arm maze for fine spatial distribution; Guo et al., Nat Med 2011), we will explore our hypothesis that space radiation decreases pattern separation in a dose- and LET-dependent manner.
- In Aim 2, using transgenic mice we have developed that allow inducible YFP labeling of neural stem cells and their progeny (nestin-CreERT2/R26R mice; Lagace et al., J Neurosci 2007), we will explore our hypothesis that space radiation negatively impacts both adult-generated (Aim 2a) and embryonic-generated (Aim 2b) DG neurons.
- In Aim 3, using transgenic mice developed by our colleagues that allow profiling of translating RNA in genetically-defined DG neural cells [BAC-TRAP mice, aka bacterial artificial chromosome translating ribosome affinity purification; Dougherty et al., Cell 2008], we will explore our hypothesis that space radiation causes discrete changes in DG neural cell types in a dose- and LET-dependent manner. Unlike currently used approaches to assess total RNA profiles from cellularly heterogeneous samples (e.g. laser capture dissection and subsequent microarray analysis), the bac-TRAP approach allows purification of specific cell types via ribosome tag and a quantitative comparison of translating RNA profiles in genetically-distinct DG cells (e.g. neural stem cells, adult-generated immature granule cell neurons, and embryonic-generated mature granule cell neurons using BAC-TRAP PBK, DCX, and Cx3Cl1 mouse lines, respectively).
Tissue from Aims 1-3 will be examined using immunohistochemistry, epifluorescent and confocal microscopy, stereologic cell counting, and morphological analysis, and tissue from Aim 3 will be explored using microarrays on the translating RNA pools and qRT-PCR. Taken together, these aims will allow us to test our overall hypothesis that radiation will have distinct, long-lasting effects on the behavioral, cellular, and molecular integrity of the hippocampus. Thus, these results will expedite the quest to estimate CNS radiation risks due to GCR exposure.