title: Involvement of cathepsin B in the motor neuron degeneration of amyotrophic lateral sclerosis.
abstract: 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.
authors.affiliation: Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 812-8582 Fukuoka, Japan. hk2068@columbia.edu
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kikuchi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamada
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Furuya
authors.forename: Katsumi
authors.initials: K
authors.lastname: Doh-ura
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Ohyagi
authors.forename: Toru
authors.initials: T
authors.lastname: Iwaki
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kira
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000150:complications / Q000201:enzymology* / Q000378:metabolism; D015153:Blotting, Western; D002401:Cathepsin B / Q000378:metabolism*; D002402:Cathepsin D / Q000378:metabolism; D056655:Cathepsin H; D056668:Cathepsin L; D002403:Cathepsins / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009410:Nerve Degeneration / Q000201:enzymology* / Q000209:etiology / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism
chemical_list: D002403:Cathepsins; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; C534281:CTSL protein, human; D056668:Cathepsin L; C534126:CTSH protein, human; D056655:Cathepsin H; D002402:Cathepsin D