title: Respiratory chain deficiency in aged spinal motor neurons.
abstract: Sarcopenia, muscle wasting, and strength decline with age, is an important cause of loss of mobility in the elderly individuals. The underlying mechanisms are uncertain but likely to involve defects of motor nerve, neuromuscular junction, and muscle. Loss of motor neurons with age and subsequent denervation of skeletal muscle has been recognized as one of the contributing factors. This study investigated aspects of mitochondrial biology in spinal motor neurons from elderly subjects. We found that protein components of complex I of mitochondrial respiratory chain were reduced or absent in a proportion of aged motor neurons-a phenomenon not observed in fetal tissue. Further investigation showed that complex I-deficient cells had reduced mitochondrial DNA content and smaller soma size. We propose that mitochondrial dysfunction in these motor neurons could lead to the cell loss and ultimately denervation of muscle fibers.
authors.affiliation: Newcastle University Centre for Brain Ageing and Vitality, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, UK; Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Karolina A
authors.initials: KA
authors.lastname: Rygiel
authors.affiliation: Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: John P
authors.initials: JP
authors.lastname: Grady
authors.affiliation: Newcastle University Centre for Brain Ageing and Vitality, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, UK; Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, UK. Electronic address: doug.turnbull@newcastle.ac.uk.
authors.forename: Doug M
authors.initials: DM
authors.lastname: Turnbull
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism* / Q000473:pathology*; D004272:DNA, Mitochondrial / Q000378:metabolism; D042967:Electron Transport Complex I / Q000172:deficiency; D005260:Female; D006801:Humans; D008297:Male; D028361:Mitochondrial Diseases / Q000209:etiology*; D009046:Motor Neurons / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure*; D055948:Sarcopenia / Q000209:etiology / Q000473:pathology; D013116:Spinal Cord / Q000166:cytology*
chemical_list: D004272:DNA, Mitochondrial; D042967:Electron Transport Complex I
keywords: Complex I; Mitochondria; Motor neuron; Sarcopenia; Spinal cord; mtDNA