Two adhesive systems cooperatively regulate axon ensheathment and myelin growth in the CNS

Nat Commun. 2019 Oct 22;10(1):4794. doi: 10.1038/s41467-019-12789-z.

Abstract

Central nervous system myelin is a multilayered membrane produced by oligodendrocytes to increase neural processing speed and efficiency, but the molecular mechanisms underlying axonal selection and myelin wrapping are unknown. Here, using combined morphological and molecular analyses in mice and zebrafish, we show that adhesion molecules of the paranodal and the internodal segment work synergistically using overlapping functions to regulate axonal interaction and myelin wrapping. In the absence of these adhesive systems, axonal recognition by myelin is impaired with myelin growing on top of previously myelinated fibers, around neuronal cell bodies and above nodes of Ranvier. In addition, myelin wrapping is disturbed with the leading edge moving away from the axon and in between previously formed layers. These data show how two adhesive systems function together to guide axonal ensheathment and myelin wrapping, and provide a mechanistic understanding of how the spatial organization of myelin is achieved.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Axons / physiology*
  • Cell Adhesion / physiology
  • Cell Adhesion Molecules, Neuronal / genetics
  • Cell Adhesion Molecules, Neuronal / metabolism
  • Central Nervous System / physiology*
  • Contactin 1 / genetics
  • Contactin 1 / metabolism
  • Female
  • Larva
  • Male
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Myelin Sheath / pathology
  • Myelin Sheath / physiology*
  • Myelin-Associated Glycoprotein / genetics
  • Myelin-Associated Glycoprotein / metabolism
  • Neural Cell Adhesion Molecules / genetics
  • Neural Cell Adhesion Molecules / metabolism*
  • Optic Nerve / metabolism
  • Optic Nerve / pathology
  • Zebrafish / genetics
  • Zebrafish Proteins / genetics
  • Zebrafish Proteins / metabolism

Substances

  • Cell Adhesion Molecules, Neuronal
  • Cntn1 protein, mouse
  • Cntnap1 protein, mouse
  • Contactin 1
  • Mag protein, mouse
  • Myelin-Associated Glycoprotein
  • Neural Cell Adhesion Molecules
  • Zebrafish Proteins
  • cntn1a protein, zebrafish