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Myelin suppresses axon regeneration by PIR-B/SHP-mediated inhibition of Trk activity

Yuki Fujita1, Shota Endo, Toshiyuki Takai

  • 1Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan.

The EMBO Journal
|March 3, 2011
PubMed

Insights

Inhibiting Paired immunoglobulin-like receptor B (PIR-B) signaling enhances central nervous system (CNS) axon regeneration. Targeting PIR-B and its associated phosphatases offers a new strategy for treating CNS injuries.

Area of Science:

  • Neuroscience
  • Cell Biology
  • Regenerative Medicine

Background:

  • Myelin-derived inhibitors like MAG impede central nervous system (CNS) axon regeneration.
  • Paired immunoglobulin-like receptor B (PIR-B) is implicated in mediating these inhibitory effects.

Purpose of the Study:

  • To investigate the molecular mechanisms by which PIR-B signaling inhibits axon regeneration.
  • To identify potential therapeutic targets for enhancing CNS repair.

Main Methods:

  • Investigated the interaction between myelin-associated glycoprotein (MAG) and PIR-B in neurons.
  • Assessed the role of Src homology 2-containing protein tyrosine phosphatases (SHP)-1 and SHP-2 in MAG-induced signaling.
  • Utilized in vivo small interfering RNA (siRNA) to inhibit SHP-1/2 in optic nerve injury models.

Main Results:

  • MAG binding to PIR-B recruits SHP-1 and SHP-2, which dephosphorylate tropomyosin receptor kinase (Trk) neurotrophin receptors.
  • Inhibition of SHP-1/2 blocks MAG-induced Trk dephosphorylation and restores neurite growth.
  • In vivo knockdown of SHP-1 or SHP-2 promotes axonal regeneration after optic nerve injury.

Conclusions:

  • PIR-B signaling, through SHP-1/2, downregulates Trk activity, inhibiting axon regeneration.
  • Targeting the PIR-B/Trk/SHP-1/2 pathway presents a promising strategy for promoting CNS repair.

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