ausblenden:
Schlagwörter:
Animals
Antioxidants/metabolism
Cell Count
Cell Death
Cerebral Cortex/*pathology
DNA, Mitochondrial/metabolism
*DNA-Binding Proteins
Disease Models, Animal
Electron Transport
High Mobility Group Proteins
Hippocampus/*pathology
In Situ Hybridization
In Situ Nick-End Labeling
Kainic Acid/administration & dosage
Mice
Mice, Knockout
Mice, Neurologic Mutants
Mitochondrial Myopathies/complications/genetics/*pathology
*Mitochondrial Proteins
Neurodegenerative Diseases/complications/genetics/*pathology
Neurons/drug effects/pathology
Nuclear Proteins/deficiency/genetics
Organ Specificity
*Oxidative Phosphorylation
RNA/metabolism
Reactive Oxygen Species/metabolism
Transcription Factors/deficiency/genetics
Zusammenfassung:
We generated mitochondrial late-onset neurodegeneration (MILON) mice with postnatal disruption of oxidative phosphorylation in forebrain neurons. They develop normally and display no overt behavioral disturbances or histological changes during the first 5 months of life. The MILON mice display reduced levels of mitochondrial DNA and mitochondrial RNA from 2 and 4 months of age, respectively, and severely respiratory chain-deficient neurons from 4 months of age. Surprisingly, these respiratory chain-deficient neurons are viable for at least 1 month without showing signs of neurodegeneration or major induction of defenses against oxidative stress. Prolonged neuronal respiratory chain deficiency is thus required for the induction of neurodegeneration. Before developing neurological symptoms, MILON mice show increased vulnerability to excitotoxic stress. We observed a markedly enhanced sensitivity to excitotoxic challenge, manifest as an abundance of terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL) reactive cells after kainic acid injection, in 4-month-old MILON mice, showing that respiratory chain-deficient neurons are more vulnerable to stress. At approximately 5-5.5 months of age, MILON mice start to show signs of disease, followed by death shortly thereafter. The debut of overt disease in MILON mice coincides with onset of rapidly progressive neurodegeneration and massive cell death in hippocampus and neocortex. This profound neurodegenerative process is manifested as axonal degeneration, gliosis, and abundant TUNEL-positive nuclei. The MILON mouse model provides a novel and powerful tool for additional studies of the role for respiratory chain deficiency in neurodegeneration and aging.
