1. Movement and structure of mitochondria in oligodendrocytes and their myelin sheaths.
- Author
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Rinholm JE, Vervaeke K, Tadross MR, Tkachuk AN, Kopek BG, Brown TA, Bergersen LH, and Clayton DA
- Subjects
- Animals, Animals, Newborn, Basic Helix-Loop-Helix Transcription Factors metabolism, Cytoplasm metabolism, Cytoplasm ultrastructure, Excitatory Amino Acid Antagonists pharmacology, Glutamic Acid pharmacology, In Vitro Techniques, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Mitochondria drug effects, Myelin Basic Protein genetics, Myelin Basic Protein metabolism, Myelin Basic Protein ultrastructure, Nerve Tissue Proteins metabolism, Oligodendrocyte Transcription Factor 2, Oligodendroglia metabolism, Organ Culture Techniques, Quinoxalines pharmacology, Rats, Rats, Wistar, Receptors, G-Protein-Coupled genetics, Receptors, G-Protein-Coupled metabolism, Sodium Channel Blockers pharmacology, Tetrodotoxin pharmacology, Mitochondria physiology, Myelin Sheath physiology, Myelin Sheath ultrastructure, Oligodendroglia ultrastructure
- Abstract
Mitochondria play several crucial roles in the life of oligodendrocytes. During development of the myelin sheath they are essential providers of carbon skeletons and energy for lipid synthesis. During normal brain function their consumption of pyruvate will be a key determinant of how much lactate is available for oligodendrocytes to export to power axonal function. Finally, during calcium-overload induced pathology, as occurs in ischemia, mitochondria may buffer calcium or induce apoptosis. Despite their important functions, very little is known of the properties of oligodendrocyte mitochondria, and mitochondria have never been observed in the myelin sheaths. We have now used targeted expression of fluorescent mitochondrial markers to characterize the location and movement of mitochondria within oligodendrocytes. We show for the first time that mitochondria are able to enter and move within the myelin sheath. Within the myelin sheath the highest number of mitochondria was in the cytoplasmic ridges along the sheath. Mitochondria moved more slowly than in neurons and, in contrast to their behavior in neurons and astrocytes, their movement was increased rather than inhibited by glutamate activating NMDA receptors. By electron microscopy we show that myelin sheath mitochondria have a low surface area of cristae, which suggests a low ATP production. These data specify fundamental properties of the oxidative phosphorylation system in oligodendrocytes, the glial cells that enhance cognition by speeding action potential propagation and provide metabolic support to axons., (© 2016 Wiley Periodicals, Inc.)
- Published
- 2016
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