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Complement-mediated muscle cell lysis: a possible mechanism of myonecrosis in anti-SRP associated necrotizing

Arada Rojana-udomsart1, Chalermchai Mitrpant, Christine Bundell

  • 1Australian Neuro-muscular Research Institute and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Queen Elizabeth II Medical Centre, Perth, WA, Australia.

Journal of Neuroimmunology
|September 18, 2013
PubMed

Insights

Antibodies to signal recognition particle (SRP) cause muscle damage through a complement-dependent mechanism. Complement activation significantly reduces myoblast survival in necrotizing myopathy patients.

Area of Science:

  • Immunology
  • Neurology
  • Cell Biology

Background:

  • Necrotizing myopathy linked to anti-SRP antibodies lacks a clear pathogenic mechanism.
  • Signal recognition particle (SRP) is crucial for protein targeting.

Purpose of the Study:

  • To investigate the role of complement in anti-SRP antibody-mediated myotoxicity.
  • To explore the mechanism of cell damage in anti-SRP-associated myopathy.

Main Methods:

  • Myoblast cultures were incubated with anti-SRP serum and complement.
  • Cell viability was assessed.
  • Immunostaining was performed on cell cultures and patient muscle biopsies for SRP, C3c, and C5b-9.

Main Results:

  • Anti-SRP serum alone caused minimal reduction in myoblast viability.
  • Addition of complement markedly decreased cell survival.
  • Complement components (C3c, C5b-9) and SRP were detected on the surface of myoblasts and in patient biopsies.

Conclusions:

  • The findings support a complement-dependent, antibody-mediated pathway in anti-SRP-associated necrotizing myopathy.
  • Complement activation is a key factor in the pathogenesis of this condition.
Keywords:
Anti-SRP antibodyComplement mediated cell lysisNecrotizing myopathy

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