The accumulation of cellular damage, including DNA damage, is hypothesized to contribute to aging-related neurodegenerative changes. DNA excision repair cross-complementing group 1 (Ercc1) knock-out mice represent an accepted model of neuronal aging, showing gradual neurodegenerative changes, including loss of synaptic contacts and cell body shrinkage. Here, we used the Purkinje cell-specific Ercc1 DNA-repair knockout mouse model to study aging in the mouse cerebellum. We performed an in-depth quantitative proteomics analysis, using stable isotope dimethyl labeling, to decipher changes in protein expression between the early (8 weeks), intermediate (16 weeks), and late (26 weeks) stages of the phenotypically aging Ercc1 knock-out and healthy littermate control mice. The expression of over 5,200 proteins from the cerebellum was compared quantitatively, whereby 79 proteins ( i.e. 1.5%) were found to be substantially regulated during aging. Nearly all of these molecular markers of the early aging onset belonged to a strongly interconnected network involved in excitatory synaptic signaling. Using immunohistological staining, we obtained temporal and spatial profiles of these markers confirming not only the proteomics data but in addition revealed how the change in protein expression correlates to synaptic changes in the cerebellum. In summary, this study provides a highly comprehensive spatial and temporal view of the dynamic changes in the cerebellum and Purkinje cell signaling in particular, indicating that synapse signaling is one of the first processes to be affected in this premature aging model, leading to neuron morphological changes, neuron degeneration, inflammation, and ultimately behavior disorders.

dx.doi.org/10.1074/mcp.M112.024950, hdl.handle.net/1765/64068
Molecular and Cellular Proteomics
This work was funded by the European Commission 7th Framework Programme; grant id fp7/262067 - Proteomics Research Infrastructure Maximising knowledge EXchange and access (XS) (PRIME-XS), This work was funded by the European Commission 7th Framework Programme; grant id fp7/200880 - European Study to Establish Biomarkers of Human Ageing (MARK-AGE), This work was funded by the European Commission 7th Framework Programme; grant id fp7/259893 - The DNA damage response and breast cancer (DDRESPONSE)
Department of Neuroscience

de Graaf, E.L, Vermeij, W.P, de Waard, M.C, Rijksen, Y.M, van der Pluijm, I, Hoogenraad, C.C, … Heck, A.J.R. (2013). Spatio-temporal analysis of molecular determinants of neuronal degeneration in the aging mouse cerebellum. Molecular and Cellular Proteomics, 12(5), 1350–1362. doi:10.1074/mcp.M112.024950