Myelin degeneration induced by mutant superoxide dismutase 1 accumulation promotes amyotrophic lateral sclerosis

Suhyun Kim, Ah Young Chung, Ji E. Na, Se J. Lee, Sang H. Jeong, Eunmi Kim, Woong Sun, Im Joo Rhyu, Hae Chul Park

Research output: Contribution to journalArticle

Abstract

Myelin is a specialized membrane that wraps around nerve fibers and is essential for normal axonal conduction in neurons. In the central nervous system, oligodendrocytes are responsible for myelin formation. Recent studies have reported pathological abnormalities in oligodendrocytes in human patients with amyotrophic lateral sclerosis (ALS) and a mouse model of ALS expressing the G93A mutation of the human superoxide dismutase 1 (mtSOD1). However, it is unclear whether oligodendrocyte pathology in ALS represents the primary dysfunction induced by mtSOD1 and how mtSOD1 contributes to oligodendrocyte degeneration and ALS pathogenesis. We analyzed GAL4-VP16-UAS transgenic zebrafish selectively expressing mtSOD1 in mature oligodendrocytes. We observed that mtSOD1 directly induced oligodendrocyte degeneration by disrupting the myelin sheath and downregulating monocarboxylate transporter 1 (MCT1), thereby causing spinal motor neuron degeneration. Pathological changes observed in this transgenic zebrafish were similar to the pathology observed in the SOD1G93A mouse model of ALS, which is characterized by expression of mtSOD1 in all cells. In addition, oligodendrocyte dysfunction induced by mtSOD1 was associated with anxiety-related behavioral abnormalities, learning impairments, and motor defects in the early symptomatic stage. We also found that treatment with potassium channel inhibitors rescued behavioral abnormalities without rescuing MCT1 expression, suggesting that myelin disruption induces behavioral abnormalities independently of MCT1. These results indicate that mtSOD1-induced dysfunction of mature oligodendrocytes is sufficient to induce motor neuron degeneration, thus informing future therapeutic strategies targeted at oligodendrocytes in ALS.

Original languageEnglish
JournalGLIA
DOIs
Publication statusPublished - 2019 Jan 1

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Oligodendroglia
Amyotrophic Lateral Sclerosis
Myelin Sheath
Mutation
Nerve Degeneration
Motor Neurons
Zebrafish
Pathology
Superoxide Dismutase-1
Potassium Channels
Nerve Fibers
Down-Regulation
Anxiety
Central Nervous System
Learning
Neurons
Membranes
Therapeutics

Keywords

  • amyotrophic lateral sclerosis
  • myelination
  • oligodendrocytes
  • superoxide dismutase 1
  • zebrafish

ASJC Scopus subject areas

  • Neurology
  • Cellular and Molecular Neuroscience

Cite this

Myelin degeneration induced by mutant superoxide dismutase 1 accumulation promotes amyotrophic lateral sclerosis. / Kim, Suhyun; Chung, Ah Young; Na, Ji E.; Lee, Se J.; Jeong, Sang H.; Kim, Eunmi; Sun, Woong; Rhyu, Im Joo; Park, Hae Chul.

In: GLIA, 01.01.2019.

Research output: Contribution to journalArticle

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