Involvement of cathepsin B in the motor neuron degeneration of amyotrophic lateral sclerosis

Acta Neuropathol. 2003 May;105(5):462-8. doi: 10.1007/s00401-002-0667-9. Epub 2003 Jan 29.


Abnormal proteolysis may be involved in the motor neuron degeneration of amyotrophic lateral sclerosis (ALS). Although several studies of the ubiquitin-proteasome system in ALS have been reported, the endosome-lysosome system has not been investigated in detail. To clarify the association of neurodegeneration with the endosome-lysosome system in ALS, we examined the pathological expression of cysteine proteases such as cathepsins B, H and L and an aspartate protease, cathepsin D, in the anterior horns of 15 ALS cases and 5 controls. In the ALS cases, cathepsin B immunoreactivity was preferentially decreased in the lateral parts of the anterior gray horns compared with the controls. Its immunoreactivity was increased in the cytoplasm of both shrunken and pigmented neurons but was weak in the neurons containing Bunina bodies. In addition, reactive astrocytes were also immunolabeled with cathepsin B. Cathepsin H and cathepsin L were detected in the cytoplasm of a small number of shrunken and pigmented neurons. Cathepsin D immunoreactivity was strong in the cytoplasm of all motor neurons. The immunoreactivity of cathepsins H, L and D was not significantly different between control and ALS cases. Western blot analysis showed that the 25-kDa activated form of cathepsin B was down-regulated in ALS. Our results suggest that cathepsin B is involved in the motor neuron degeneration in ALS.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Amyotrophic Lateral Sclerosis / complications
  • Amyotrophic Lateral Sclerosis / enzymology*
  • Amyotrophic Lateral Sclerosis / metabolism
  • Blotting, Western
  • Cathepsin B / metabolism*
  • Cathepsin D / metabolism
  • Cathepsin H
  • Cathepsin L
  • Cathepsins / metabolism
  • Cysteine Endopeptidases / metabolism
  • Female
  • Humans
  • Immunohistochemistry
  • Male
  • Middle Aged
  • Nerve Degeneration / enzymology*
  • Nerve Degeneration / etiology
  • Nerve Degeneration / metabolism
  • Spinal Cord / cytology
  • Spinal Cord / metabolism


  • Cathepsins
  • Cysteine Endopeptidases
  • Cathepsin B
  • CTSL protein, human
  • Cathepsin L
  • CTSH protein, human
  • Cathepsin H
  • Cathepsin D