Respiratory chain deficiency in aged spinal motor neurons

• Published in: Neurobiology of aging Vol. 35; no. 10; pp. 2230 - 2238
• Main Authors: Rygiel, Karolina A., Grady, John P., Turnbull, Doug M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2014; Elsevier
• Subjects: Aged; Aged, 80 and over; Aging - metabolism; Aging - pathology; Complex I; DNA, Mitochondrial - metabolism; Electron Transport Complex I - deficiency; Female; Humans; Internal Medicine; Male; Mitochondria; Mitochondrial Diseases - etiology; Motor neuron; Motor Neurons - metabolism; Motor Neurons - pathology; Motor Neurons - ultrastructure; mtDNA; Neurology; Regular; Sarcopenia; Sarcopenia - etiology; Sarcopenia - pathology; Spinal cord; Spinal Cord - cytology; Sarcopenia; Spinal cord; Mitochondria; Motor neuron; Complex I; mtDNA
• ISSN: 0197-4580; 1558-1497; 1558-1497
• DOI: 10.1016/j.neurobiolaging.2014.02.027

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.