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Updated: May 21, 2026
Gene-environment Interaction Models to Unmask Susceptibility Mechanisms in Parkinson's Disease
Published on: January 7, 2014
Ogg1 null mice exhibit age-associated loss of the nigrostriatal pathway and increased sensitivity to MPTP
Fernando Cardozo-Pelaez1, Monica Sanchez-Contreras, Andrew B C Nevin
1Center for Environmental Health Sciences, Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT 59812, USA. Fernando.Cardozo@umontana.edu
Abstract:
Cumulative damage to cellular macromolecules via oxidative stress is a hallmark of aging and neurodegenerative disease. Whether such damage is a cause or a subsequent effect of neurodegeneration is still unknown. This paper describes the development of an age-associated mild parkinsonian model in mice that lack the DNA repair enzyme 8-oxoguanine glycosylase 1 (Ogg1). Aged OGG1 knock-out (OGG1 KO) mice show a decreased spontaneous locomotor behavior and evidence a decrease in striatal dopamine levels, a loss of tyrosine hydroxylase (TH)-positive neurons in the substantia nigra (SN), and an increase in ubiquitin-positive inclusions in their remaining SN neurons. In addition, young OGG1 KO mice are more susceptible to the dopaminergic toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) than their wild-type (WT) counterparts. Age-associated increases in 7,8-dihydro-2'-deoxyguanine (oxo(8)dG) have been reported in brain regions and neuronal populations affected in Parkinson's disease (PD), toxin-induced parkinsonian models, and mice harboring genetic abnormalities associated with PD. Because of these increased oxo(8)dG levels, the OGG1 KO mouse strain could shed light on molecular events leading to neuronal loss as a consequence of cumulative oxidative damage to DNA during aging and after toxicological challenge.
Insights
Mice lacking the OGG1 DNA repair enzyme develop age-related Parkinson
Area of Science:
- Neuroscience
- Genetics
- Molecular Biology
Background:
- Oxidative stress and cumulative DNA damage are implicated in aging and neurodegenerative diseases like Parkinson's disease (PD).
- The precise role of DNA damage in neurodegeneration remains unclear.
- 8-oxoguanine glycosylase 1 (Ogg1) is a key DNA repair enzyme.
Purpose of the Study:
- To investigate the role of oxidative DNA damage in age-associated neurodegeneration.
- To develop and characterize a novel mouse model for studying Parkinson's disease pathogenesis.
- To explore the function of the OGG1 enzyme in maintaining neuronal health during aging.
Main Methods:
- Development of OGG1 knock-out (OGG1 KO) mice.
- Assessment of age-associated behavioral and neurochemical changes in OGG1 KO mice.
- Evaluation of susceptibility to the neurotoxin MPTP in young OGG1 KO and wild-type (WT) mice.
Main Results:
- Aged OGG1 KO mice exhibited reduced locomotor activity, decreased striatal dopamine, loss of dopaminergic neurons in the substantia nigra, and increased ubiquitin inclusions.
- Young OGG1 KO mice were more vulnerable to MPTP-induced dopaminergic neurotoxicity compared to WT mice.
- Elevated levels of 7,8-dihydro-2'-deoxyguanine (oxo(8)dG), a marker of oxidative DNA damage, were observed in relevant brain regions.
Conclusions:
- The OGG1 KO mouse model recapitulates key features of age-associated parkinsonism.
- This model highlights the contribution of cumulative oxidative DNA damage to neurodegeneration.
- OGG1 deficiency exacerbates susceptibility to neurotoxic insults, implicating DNA repair in PD pathogenesis.
