Reactive astrocytes in multiple sclerosis impair neuronal outgrowth through TRPM7-mediated chondroitin sulfate proteoglycan production

Glia. 2019 Jan;67(1):68-77. doi: 10.1002/glia.23526. Epub 2018 Nov 19.

Abstract

Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system (CNS), characterized by inflammation-mediated demyelination, axonal injury and neurodegeneration. The mechanisms underlying impaired neuronal function are not fully understood, but evidence is accumulating that the presence of the gliotic scar produced by reactive astrocytes play a critical role in these detrimental processes. Here, we identified astrocytic Transient Receptor Potential cation channel, subfamily M, member 7 (TRPM7), a Ca2+ -permeable nonselective cation channel, as a novel player in the formation of a gliotic scar. TRPM7 was found to be highly expressed in reactive astrocytes within well-characterized MS lesions and upregulated in primary astrocytes under chronic inflammatory conditions. TRPM7 overexpressing astrocytes impaired neuronal outgrowth in vitro by increasing the production of chondroitin sulfate proteoglycans, a key component of the gliotic scar. These findings indicate that astrocytic TRPM7 is a critical regulator of the formation of a gliotic scar and provide a novel mechanism by which reactive astrocytes affect neuronal outgrowth.

Keywords: TRPM7; astrocytes; chondroitin sulfate proteoglycan; multiple sclerosis; neurodegeneration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Animals
  • Astrocytes / metabolism*
  • Cells, Cultured
  • Chondroitin Sulfate Proteoglycans / biosynthesis*
  • Chondroitin Sulfate Proteoglycans / genetics
  • Female
  • Humans
  • Male
  • Middle Aged
  • Multiple Sclerosis / genetics
  • Multiple Sclerosis / metabolism*
  • Multiple Sclerosis / pathology
  • Neurons / metabolism*
  • Neurons / pathology
  • Protein-Serine-Threonine Kinases / biosynthesis*
  • Protein-Serine-Threonine Kinases / genetics
  • Rats
  • TRPM Cation Channels / biosynthesis*
  • TRPM Cation Channels / genetics

Substances

  • Chondroitin Sulfate Proteoglycans
  • TRPM Cation Channels
  • Protein-Serine-Threonine Kinases
  • TRPM7 protein, human