eLife (Mar 2019)

Microglial SIRPα regulates the emergence of CD11c+ microglia and demyelination damage in white matter

  • Miho Sato-Hashimoto,
  • Tomomi Nozu,
  • Riho Toriba,
  • Ayano Horikoshi,
  • Miho Akaike,
  • Kyoko Kawamoto,
  • Ayaka Hirose,
  • Yuriko Hayashi,
  • Hiromi Nagai,
  • Wakana Shimizu,
  • Ayaka Saiki,
  • Tatsuya Ishikawa,
  • Ruwaida Elhanbly,
  • Takenori Kotani,
  • Yoji Murata,
  • Yasuyuki Saito,
  • Masae Naruse,
  • Koji Shibasaki,
  • Per-Arne Oldenborg,
  • Steffen Jung,
  • Takashi Matozaki,
  • Yugo Fukazawa,
  • Hiroshi Ohnishi

DOI
https://doi.org/10.7554/eLife.42025
Journal volume & issue
Vol. 8

Abstract

Read online

A characteristic subset of microglia expressing CD11c appears in response to brain damage. However, the functional role of CD11c+ microglia, as well as the mechanism of its induction, are poorly understood. Here we report that the genetic ablation of signal regulatory protein α (SIRPα), a membrane protein, induced the emergence of CD11c+ microglia in the brain white matter. Mice lacking CD47, a physiological ligand of SIRPα, and microglia-specific SIRPα-knockout mice exhibited the same phenotype, suggesting that an interaction between microglial SIRPα and CD47 on neighbouring cells suppressed the emergence of CD11c+ microglia. A lack of SIRPα did not cause detectable damage to the white matter, but resulted in the increased expression of genes whose expression is characteristic of the repair phase after demyelination. In addition, cuprizone-induced demyelination was alleviated by the microglia-specific ablation of SIRPα. Thus, microglial SIRPα suppresses the induction of CD11c+ microglia that have the potential to accelerate the repair of damaged white matter.

Keywords