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A neuronal DNA damage response is detected at the earliest stages of Alzheimer's neuropathology and correlates with cognitive impairment in the Medical Research Council's Cognitive Function and Ageing Study ageing brain cohort

Simpson, Julie E.; Ince, Paul G.; Matthews, Fiona E.; Shaw, Pamela J.; Heath, Paul R.; Brayne, Carol; Garwood, Claire; Higginbottom, Adrian; Wharton, Stephen B.

Authors

Julie E. Simpson

Paul G. Ince

Pamela J. Shaw

Paul R. Heath

Carol Brayne

Claire Garwood

Adrian Higginbottom

Stephen B. Wharton



Abstract

Aims: Population-based studies have shown that approximately 20% of the ageing population (aged 65 years and over) with dementia have little or no classical Alzheimer-type neuropathology. Cumulative DNA damage and a reduced capacity of DNA repair may result in neuronal dysfunction and contribute to cognitive impairment independent of Alzheimer-type pathology in the ageing brain. Methods: We investigated expression of the DNA damage response (DDR)-associated molecules γH2AX and DNA-PKcs using immunohistochemistry and western blotting, and senescence-associated β-galactosidase in the frontal association neocortex of cases with low levels of Alzheimer-type pathology (Braak & Braak stage 0-II), and explored their relationship to cognitive impairment in a population-representative sample from the Medical Research Council's Cognitive Function and Ageing Study cohort. Results: Increases in both γH2AX+ (rs=-0.36, P=0.025) and DNA-PKcs+ (rs=-0.39, P=0.01) neuronal counts were associated with a lower Mini-Mental State Examination score. Increasing levels of senescence associated-β-gal+ pyramidal neurones were weakly associated with the total number of DNA-PKcs+ neurones (P=0.08), but not with traditional senescence-associated signalling molecules, including p53 and p16. Conclusion: The association between the neuronal DDR and cognitive impairment, independent of AD pathology in the ageing brain, may be suggestive of a causal link via neuronal dysfunction.

Citation

Simpson, J. E., Ince, P. G., Matthews, F. E., Shaw, P. J., Heath, P. R., Brayne, C., …Wharton, S. B. (2015). A neuronal DNA damage response is detected at the earliest stages of Alzheimer's neuropathology and correlates with cognitive impairment in the Medical Research Council's Cognitive Function and Ageing Study ageing brain cohort. Neuropathology and Applied Neurobiology, 41(4), 483-496. https://doi.org/10.1111/nan.12202

Journal Article Type Article
Publication Date Jun 1, 2015
Deposit Date Dec 8, 2023
Journal Neuropathology and Applied Neurobiology
Print ISSN 0305-1846
Electronic ISSN 1365-2990
Publisher British Neuropathological Society
Volume 41
Issue 4
Pages 483-496
DOI https://doi.org/10.1111/nan.12202
Public URL https://hull-repository.worktribe.com/output/4454155