Demonstration of cathepsins B, H and L in xenografts of normal and Duchenne-muscular-dystrophy muscles transplanted into nude mice

Abstract

The activities and contents of the lysosomal cysteine proteinases cathepsins B, H and L were examined in xenografts of biopsied muscles transplanted from age-matched normal subjects and Duchenne-muscular-dystrophy (DMD) patients into nude mice. The activity of cathepsin B increased 9-fold and that of B-plus-L increased 24-fold in the first week after transplantation in normal muscle xenografts. By the third week, the activity of cathepsin B increased a total of 20-fold and B-plus-L increased to 36-fold the original level. The activity levels of cathepsin B, B-plus-L, H and D, and acid phosphatase in normal and DMD xenografts were not significantly different when compared 2 weeks after transplantation. However, the protein content of cathepsin B in DMD muscle xenografts was more than 3-fold that of normal xenografts at 2 weeks. The profile of cathepsin H activity in normal muscle xenografts was different than those of cathepsins B and B-plus-L. In the first week, the cathepsin H diminished sharply to about one-third of the biopsied muscle level and then, by 3 weeks after transplantation, it had increased slightly to about half the original level. The amount of endogenous cysteine-proteinase inhibitor changed in parallel with the activity of cathepsins B and B-plus-L. Cathepsins B and H, but not cathepsin L, were found immunohistochemically in regenerating muscle fibres of normal and DMD xenografts 2 weeks after transplantation. Staining of cathepsin B in DMD xenografts was slightly stronger than that in normal subjects. There was no immunostaining in degenerating or necrotic muscle fibres 2 weeks after transplantation. Western-blot analysis revealed that the cathepsin B band at 29 kDa was increased in normal xenografts 2 and 3 weeks after transplantation. Also, 2 weeks after transplantation the staining intensity of this band was slightly stronger in DMD xenografts than in normal xenografts. These results suggest that cathepsin B participates in the regeneration of transplanted muscle, both normal and DMD, and in the DMD muscle fibre-wasting processes, during regeneration.

VBP15, a novel anti‐inflammatory and membrane‐stabilizer, improves muscular dystrophy without side effects

“…Optical imaging of live animals was used to monitor muscle inflammation. ProSense 680, a substrate cleaved by cathepsin proteases upregulated in DMD (Kar & Pearson, ; Takeda et al, ), was injected as previously reported (Baudy et al, ). Cathepsin activity was elevated in mdx mice (Fig E, Supporting Information Fig 1B and C).…”

Molecular Cloning and Structural and Functional Characterization of Human Cathepsin F, a New Cysteine Proteinase of the Papain Family with a Long Propeptide Domain

“…Nevertheless, it is remarkable that cathepsin F expression levels in normal tissues exhibit a large variability, and there are tissues such as skeletal muscle and testis, in which its mRNA levels are up to 20-fold higher than in others such as kidney and colon, which also produce this novel protease, albeit at low levels. The finding of very high levels of cathepsin F mRNA in skeletal muscle is of particular interest in light of previous data reporting an essential role of cysteine proteinases in muscle proteolysis in both normal and pathological conditions, including some forms of muscular dystrophy (62)(63)(64). Further studies will be required to evaluate the possibility that cathepsin F could be responsible for the catabolism of specific protein substrates in the muscle.…”

Insulin-Like Growth Factor-I and High Protein Diet Decrease Calpain-Mediated Proteolysis in Murine Muscular Dystrophy

“…TWO factors shown to reduce rates of proteolysis in dystrophic muscle are rhIGF-I administration and a high-protein diet (HPD) (8)(9)(10). In both dystrophic mice and hamsters, longterm treatment with rhIGF-I and/or HPD was effective in reducing overall and myofibrillar proteolysis in these animals.…”