Large-scale electron microscopic volume imaging of interfascicular oligodendrocytes in the mouse corpus callosum

Tatsuhide Tanaka, Nobuhiko Ohno, Yasuyuki Osanai, Sei Saitoh, Truc Quynh Thai, Kazuya Nishimura, Takeaki Shinjo, Shoko Takemura, Kouko Tatsumi, Akio Wanaka

Research output: Contribution to journalArticlepeer-review

Abstract

Single oligodendrocytes produce myelin sheaths around multiple axons in the central nervous system. Interfascicular oligodendrocytes (IOs) facilitate nerve conduction, but their detailed morphologies remain largely unknown. In the present study, we three-dimensionally reconstructed IOs in the corpus callosum of adult mouse using serial block face scanning electron microscopy. The cell bodies of IOs were morphologically polarized and extended thick processes from the cytoplasm-rich part of the cell. Processes originating from the cell body of each IO can be classified into two types: one myelinates an axon without branching, while the other type branches and each branch myelinates a distinct axon. Myelin sheaths originating from a particular IO have biased thicknesses, wrapping axons of a limited range of diameters. Consistent with this finding, IOs transduced and visualized with a rabies viral vector expressing GFP showed statistically significant variation in their myelination patterns. We further reconstructed the sheath immediately adjacent to that derived from each of the analyzed IOs; the thicknesses of the pair of sheaths were significantly correlated despite emanating from different IOs. These results suggest that a single axon could regulate myelin sheath thicknesses, even if the sheaths are derived from distinct IOs. Collectively, our results indicate that the IOs have their own myelin profiles defined by myelin thickness and axonal diameter although axons may regulate thickness of myelin sheath.

Original languageEnglish
Pages (from-to)2488-2502
Number of pages15
JournalGLIA
Volume69
Issue number10
DOIs
Publication statusAccepted/In press - 2021

All Science Journal Classification (ASJC) codes

  • Neurology
  • Cellular and Molecular Neuroscience

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