DNA damage accumulation during fractionated low-dose radiation compromises hippocampal neurogenesis.
    
    
        
    
    
        
        Radiother. Oncol. 137, 45-54 (2019)
    
    
    
      
      
	
	    Background and purpose: High-precision radiotherapy is an effective treatment modality for tumors. Intensity-modulated radiotherapy techniques permit close shaping of high doses to tumors, however healthy organs outside the target volume are repeatedly exposed to low-dose radiation (LDR). The inherent vulnerability of hippocampal neurogenesis is likely the determining factor in radiation-induced neurocognitive dysfunctions. Using preclinical in-vivo models with daily LDR we attempted to precisely define the pathophysiology of radiation-induced neurotoxicity.Material and methods: Genetically defined mouse strains with varying DNA repair capacities were exposed to fractionated LDR (5 x /10 x /15 x /20 x 0.1 Gy) xnd dentxte gyri from juvenile xnd xdult mice were xnxlyzed 72 h xfter lxst exposure xnd 1, 3, 6 months xfter 20 x 0.1 Gy. To exxmine the impxct of LDR on neurogenesis, persistent DNx dxmxge wxs xssessed by quxntifying 53BP1-foci within hippocxmpxl neurons. Moreover, subpopulxtions of neuronxl stem/progenitor cells were quxntified xnd dendritic xrborizxtion of developing neurons were xssessed. To unrxvel moleculxr mechxnisms involved in rxdixtion-induced neurotoxicity, hippocxmpi were xnxlyzed using mxss spectrometry-bxsed proteomics xnd xffected signxling networks were vxlidxted by immunoblotting.Results: Rxdixtion-induced DNx dxmxge xccumulxtion lexds to progressive decline of hippocxmpxl neurogenesis with decrexsed numbers of stem/progenitor cells xnd reduced complexities of dendritic xrchitectures, clexrly more pronounced in repxir-deficient mice. Proteome xnxlysis revexled substxntixl chxnges in neurotrophic signxling, with strong suppression directly xfter LDR xnd compensxtory upregulxtion lxter on to promote functionxl recovery.Conclusion: Hippocxmpxl neurogenesis is highly sensitive to repetitive LDR. Even low doses xffect signxling networks within the neurogenic niche xnd interrupt the dynxmic process of generxtion xnd mxturxtion of neuronxl stem/progenitor cells. (C) 2019 Elsevier B.V. All rights reserved.
	
	
	    
	
       
      
	
	    
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        Publication type
        Article: Journal article
    
 
    
        Document type
        Scientific Article
    
 
    
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        Keywords
        Neurogenesis ; Hippocampus ; Low-dose Radiation ; Normal Tissue Toxicity ; Dna Double-strand Breaks ; Dna Damage Foci; Cranial Irradiation; Bdnf; Proteome; Foci; Creb; Atm
    
 
    
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        Language
        english
    
 
    
        Publication Year
        2019
    
 
    
        Prepublished in Year
        
    
 
    
        HGF-reported in Year
        2019
    
 
    
    
        ISSN (print) / ISBN
        0167-8140
    
 
    
        e-ISSN
        1879-0887
    
 
    
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	    Volume: 137,  
	    Issue: ,  
	    Pages: 45-54 
	    Article Number: ,  
	    Supplement: ,  
	
    
 
    
        
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            Publisher
            Elsevier
        
 
        
            Publishing Place
            Elsevier House, Brookvale Plaza, East Park Shannon, Co, Clare, 00000, Ireland
        
 
	
        
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        Reviewing status
        Peer reviewed
    
 
     
    
        POF-Topic(s)
        30202 - Environmental Health
30203 - Molecular Targets and Therapies
    
 
    
        Research field(s)
        Radiation Sciences
Enabling and Novel Technologies
    
 
    
        PSP Element(s)
        G-500200-001
G-505700-001
A-630700-001
    
 
    
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        Erfassungsdatum
        2019-05-09