Mitochondria in amyotrophic lateral sclerosis: a trigger and a target.
Strong evidence shows that mitochondrial dysfunction is involved in amyotrophic lateral sclerosis (ALS), but despite the fact that mitochondria play a central role in excitotoxicity, oxidative stress and apoptosis, the intimate underlying mechanism linking mitochondrial defects to motor neuron degeneration in ALS still remains elusive. Morphological and functional abnormalities occur in mitochondria in ALS patients and related animal models, although their exact nature and extent are controversial. Recent studies postulate that the mislocalization in mitochondria of mutant forms of copper-zinc superoxide dismutase (SOD1), the only well-documented cause of familial ALS, may account for the toxic gain of function of the enzyme, and hence induce motor neuron death. On the other hand, mitochondrial dysfunction in ALS does not seem to be restricted only to motor neurons as it is also present in other tissues, particularly the skeletal muscle. The presence of this 'systemic' defect in energy metabolism associated with the disease is supported in skeletal muscle tissue by impaired mitochondrial respiration and overexpression of uncoupling protein 3. In addition, the lifespan of transgenic mutant SOD1 mice is increased by a highly energetic diet compensating both the metabolic defect and the motorneuronal function. In this review, we will focus on the mitochondrial dysfunction linked to ALS and the cause-and-effect relationships between mitochondria and the pathological mechanisms thought to be involved in the disease.
Dupuis
Luc
L
Laboratoire de Signalisations Moléculaires et Neurodégénérescence, U692 INSERM, Faculté de Médecine, Université Louis Pasteur, Strasbourg, France.
Gonzalez de Aguilar
Jose-Luis
JL
Oudart
Hugues
H
de Tapia
Marc
M
Barbeito
Luis
L
Loeffler
Jean-Philippe
JP
D000690:Amyotrophic Lateral Sclerosis / Q000209:etiology* / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D016923:Cell Death / Q000235:genetics; D019069:Cell Respiration / Q000235:genetics; D006801:Humans; D008928:Mitochondria / Q000201:enzymology* / Q000473:pathology; D028361:Mitochondrial Diseases / Q000150:complications* / Q000378:metabolism* / Q000503:physiopathology; D009046:Motor Neurons / Q000201:enzymology* / Q000473:pathology; D018482:Muscle, Skeletal / Q000201:enzymology / Q000503:physiopathology; D018384:Oxidative Stress / Q000235:genetics; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D000072105:Superoxide Dismutase-1
C000606290:SOD1 protein, human; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1