Related Experiment Video
Updated: Aug 19, 2026
Social Threat-Safety Test Uncovers Psychosocial Stress-Related Phenotypes
Published on: December 15, 2023
Selective neuronal vulnerability and inadequate stress response in superoxide dismutase mutant mice
Stephen Lynn1, Eric J Huang, Sailaja Elchuri
1Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA.
Abstract:
To understand the role of oxidative stress and mitochondrial defects in the development of neurodegeneration, we examined the age-related pathological changes and corresponding gene expression profiles in homozygous mutant mice deficient in the mitochondrial form of superoxide dismutase (MnSOD, SOD2). These Sod2-/- mice, generated on a B6D2F1 background, developed ataxia at Postnatal Day (P) 11 and progressively deteriorated with frequent seizures by P14. Histopathological examination revealed neurodegenerative changes consistent with the neurological signs. Vacuolar degeneration was observed in neurons and neuropil throughout the brainstem and rostral cortex. The motor trigeminal nucleus in brainstem and the deeper layers of the motor cortex were the earliest regions to degenerate, with the thalamus and hippocampus affected at later stages. Oligonucleotide microarrays were used to compare gene expression profiles in the brainstem and thalamus of Sod2+/+ and -/- mice from birth to P18. Notably, a large set of heat-shock protein genes was transcriptionally down regulated, and this was most likely due to a reduction in the heat-shock transcription factor 1 (HSF1). Other major classes of differentially expressed genes include lipid biosynthesis and ROS metabolism.
Insights
Mice lacking mitochondrial superoxide dismutase (MnSOD, SOD2) developed neurodegeneration and seizures. Gene expression changes revealed reduced heat-shock proteins, impacting cellular defense mechanisms in this oxidative stress model.
Area of Science:
- Neuroscience
- Mitochondrial Biology
- Genetics
Background:
- Oxidative stress and mitochondrial dysfunction are implicated in neurodegenerative diseases.
- Mitochondrial superoxide dismutase (MnSOD, SOD2) plays a crucial role in mitigating reactive oxygen species (ROS).
Purpose of the Study:
- To investigate the link between oxidative stress, mitochondrial defects, and neurodegeneration.
- To characterize the pathological and gene expression changes in mice lacking MnSOD (Sod2-/-).
Main Methods:
- Generated homozygous mutant mice (Sod2-/-) on a B6D2F1 background.
- Performed histopathological examination to identify neurodegenerative changes.
- Utilized oligonucleotide microarrays to analyze brain gene expression profiles from birth to P18.
Main Results:
- Sod2-/- mice exhibited ataxia by P11 and seizures by P14, with widespread vacuolar degeneration in neurons and neuropil.
- Early degeneration was observed in the motor trigeminal nucleus and motor cortex, followed by the thalamus and hippocampus.
- Gene expression analysis revealed downregulation of heat-shock protein genes, linked to reduced heat-shock transcription factor 1 (HSF1), and altered lipid biosynthesis and ROS metabolism pathways.
Conclusions:
- Mitochondrial MnSOD deficiency leads to severe neurodegeneration, highlighting the critical role of this enzyme in neuronal health.
- Downregulation of heat-shock proteins and altered cellular metabolism are key molecular events in this neurodegenerative model.
- This study provides insights into the mechanisms of neurodegeneration driven by oxidative stress and mitochondrial dysfunction.
