Inefficient DNA repair is an aging-related modifier of Parkinson disease

The underlying relation between Parkinson disease (PD) etiopathology and its major risk factor, aging, is largely unknown. The nature of the specific age-related mechanisms promoting PD onset is experimentally difficult to elucidate because aging is a highly complex process contributed by multiple factors. Recent evidence, however, established a strong and causative link between genome stability and aging. To investigate a possible nexus between DNA damage accumulation, aging, and PD we examined DNA repair pathways associated with aging in laboratory animal models and human cases. We demonstrate that dermal fibroblasts from PD patients display flawed nucleotide excision repair (NER) capacity and that NER-defective mice exhibit typical PD-like pathological alterations, including decreased dopaminergic innervation in the striatum, increased phospho-synuclein levels, and defects in mitochondrial respiration. NER mouse mutants are also more sensitive to the prototypical PD toxin MPTP and their transcriptomic landscape shares important similarities with that of PD patients. Overall, our results demonstrate that specific defects in DNA repair impact the dopaminergic system, are associated with human PD pathology, and might therefore constitute a novel risk factor for PD by affecting the aging process. Overall design: In total 8 samples were analyzed, 4 controls and 4 Ercc1 mutants.