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DNA-fragmentation and apoptosis-related proteins of muscle cells in motor neuron disorders

D S Tews1, H H Goebel, H M Meinck

  • 1Division of Neuropathology, Johannes-Gutenberg-University Medical Center, Mainz, Germany.

Acta Neurologica Scandinavica
|February 4, 1998
PubMed

Insights

Muscle fibers in denervating disorders like ALS and polyneuropathy undergo apoptosis, a programmed cell death. This process involves pro-apoptotic factors (Bax, ICE) and anti-apoptotic factors (Bcl-2).

Area of Science:

  • Muscle biology
  • Cellular apoptosis
  • Neurodegenerative diseases

Background:

  • Apoptosis (programmed cell death) is a known cause of muscle fiber loss in infantile spinal muscular atrophy.
  • The role of muscle fiber apoptosis in other denervating disorders remains less understood.

Purpose of the Study:

  • To investigate the involvement of muscle fiber apoptosis in Amyotrophic Lateral Sclerosis (ALS) and polyneuropathy.
  • To analyze DNA fragmentation and apoptosis-related protein expression in muscle fibers of patients with these conditions.

Main Methods:

  • Utilized the TUNEL assay to detect DNA fragmentation, a key indicator of apoptosis.
  • Examined the expression patterns of apoptosis-related proteins, including Bax, ICE, and Bcl-2, in muscle fibers.

Main Results:

  • Identified DNA cleavage in muscle fibers of all studied patients with ALS and polyneuropathy.
  • Observed strong expression of pro-apoptotic factors (Bax, ICE) and the anti-apoptotic factor (Bcl-2) in muscle fibers.
  • Evidence suggests actin cleavage, potentially forming apoptotic bodies.

Conclusions:

  • Defective innervation in ALS and polyneuropathy may trigger an intrinsic muscle fiber "suicide" program.
  • Pro-apoptotic factors (Bax, ICE) promote apoptosis, while anti-apoptotic factor (Bcl-2) counteracts these effects.
  • Muscle fibers exhibit a complex interplay of pro- and anti-apoptotic mechanisms in response to denervation.

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