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Analyzing Mitochondrial Transport and Morphology in Human Induced Pluripotent Stem Cell-Derived Neurons in Hereditary Spastic Paraplegia
Published on: February 9, 2020
Mitochondrial oxidative metabolism in motor neuron degeneration (mnd) mouse central nervous system
M Bertamini1, B Marzani, R Guarneri
1Department of Molecular and Cellular Physiological and Pharmacological Sciences, University of Pavia, Piazza Botta 11, 27100 Pavia, Italy.
Abstract:
The mnd mouse spontaneously develops slowly evolving motoneuron pathology leading to progressive motor impairment. There is strong evidence that a complex interplay between oxidative stress, mitochondria abnormalities and alteration of glutamate neurotransmission plays an important role in the pathogenesis of motor neuron diseases. Therefore, we investigated the presence of mitochondrial dysfunction in frontal, central (comprising the motor area) and occipital regions of the cerebral cortex and in the spinal cord of 35-week-old mnd mice. Lipid peroxide derivatives reacting with thiobarbituric acid (TBARS) were measured in the cervical, thoracic and lumbar spinal cord. In addition biochemical and behavioural analyses were carried out in mnd mice chronically treated with l-carnitine from the 11th to the 34th week of life (mndT mice). Slight but significant alterations of mitochondrial enzyme activities were seen in the mnd cortical regions. The central area was the most affected and both complex I, IV and citrate synthase were decreased with respect to controls. The rate of oxygen consumption (QO2) was markedly decreased in both the upper (cervical + upper portion of the thoracic region) and lower (lumbar + lower portion of the thoracic region) mnd spinal cord. The level of TBARS showed a rostro-caudal trend to increase, being 30% higher in the lumbar tract of mnd mice in comparison with controls. L-carnitine treatment increased the mitochondrial enzyme activities in cortical regions towards control value and was effective in enhancing QO2 and decreasing TBARS levels in the spinal cord of mndT. Behavioural testing showed that L-carnitine significantly delayed the onset of motor behaviour impairment. This beneficial effect was declining at 35 week of age, when the biochemical measurements were performed.
Insights
Mitochondrial dysfunction contributes to motor neuron disease in mnd mice. L-carnitine treatment improved mitochondrial function and delayed motor impairment, suggesting a therapeutic role.
Area of Science:
- Neuroscience
- Mitochondrial Biology
- Neurodegenerative Diseases
Background:
- Motor neuron diseases involve oxidative stress, mitochondrial dysfunction, and altered glutamate neurotransmission.
- The mnd mouse model exhibits progressive motoneuron pathology and motor impairment.
Purpose of the Study:
- To investigate mitochondrial dysfunction in the cerebral cortex and spinal cord of mnd mice.
- To evaluate the therapeutic potential of L-carnitine in mitigating motor neuron disease pathology.
Main Methods:
- Biochemical analysis of mitochondrial enzyme activities and oxygen consumption (QO2) in cortical and spinal cord tissues.
- Measurement of lipid peroxidation (TBARS) in spinal cord sections.
- Behavioral testing of mnd mice treated with L-carnitine.
Main Results:
- Mnd mice showed decreased mitochondrial enzyme activities (Complex I, IV, citrate synthase) in the central cortex and reduced QO2 in the spinal cord.
- Increased TBARS levels were observed in the lumbar spinal cord of mnd mice.
- L-carnitine treatment normalized mitochondrial enzyme activities, enhanced QO2, reduced TBARS, and delayed motor impairment onset.
Conclusions:
- Mitochondrial dysfunction is a key feature of motor neuron pathology in mnd mice.
- L-carnitine demonstrates neuroprotective effects by improving mitochondrial function and reducing oxidative stress.
- L-carnitine holds promise as a therapeutic agent for motor neuron diseases.
