Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.36 (caspase-1)
 6,285 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although numerous sarcolemmal protein defects in muscular dystrophies have been identified, the mechanisms linking these defects and muscle fibre degeneration are not fully characterized. As there is evidence that apoptosis is part of muscle fibre loss in dystrophin-deficient mdx-mice, apoptotic muscle fibre death may also play a role in humans with muscular dystrophies. We investigated in-situ DNA-fragmentation by the TUNEL-method and expression of apoptosis-related proteins immunohistochemically in 14 children suffering from deficiencies of dystrophin, adhalin, and merosin, and found TUNEL-positive chromatin-cleavage of muscle fibre nuclei in about 10% of non-necrotic muscle fibres. DNA-fragmentation also occurred in groups of 'necrotic and regenerating' muscle fibres with labelling of nuclei in myogenic cells and phagocytizing macrophages. These lesions also revealed expression of apoptosis-promoting factors, such as bax and ICE, inducing cleavage of myofilaments, and of the apoptosis-inhibiting proteins bcl-XL and bcl-2 which neutralized high bax levels. Mimicking embryonal myogenesis, chromatin-fragmentation in 'necrotic and regenerating' areas seems to be part of the regulating events in muscle regeneration to eliminate excessive proliferating satellite cells. Nevertheless, macrophages are also affected by apoptosis after successful removal of necrotic fibres. In humans, DNA-fragmentation and expression of apoptosis-related proteins indicate that apoptosis plays a role in muscle degeneration and regeneration in muscular dystrophies.
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PMID:DNA-fragmentation and expression of apoptosis-related proteins in muscular dystrophies. 929 73

Apoptosis is well accepted as a type of cell death occurring in the development of mammalian muscles, but the death of adult myofibres in neuromuscular disorders and exercise-induced muscle damage is usually explained in terms of muscle necrosis. The current view that apoptosis precedes necrosis in death of dystrophin-deficient muscle fibres of mdx mouse has been well substantiated. Moreover, apoptotic myonuclei have been reported to increase in mdx mice 2 days after spontaneous exercise. To investigate the contribution of apoptosis to exercise-induced damage of normal muscle fibre a time-course analysis has been performed in adult C57BL/6 mice. Groups of five mice were sacrificed immediately after the end of the exercise, and after a rest period of 6 or 96 h. The amount of apoptosis in leg muscles was assessed by electron microscopy, by the terminal deoxynucleotidyl transferase assay and by electrophoretic detection of fragmented DNA; the expression of Bcl-2, Bax, Fas, ICE, p53 and ubiquitin was examined by immunohistochemistry and Western blot. Absent in muscles of normal 'sedentary' mice, apoptotic myonuclei peak in muscles of normal mice after a night of spontaneous wheel-running (4% +/- 3.5, immediately and 2.5% +/- 1.8 after 6 h rest, P < 0.05 vs non-runner mice); they then decrease but are present 4 days later (0.8% +/- 1.5). Satellite cells are also involved in the apoptotic process. Myofibre content of Bcl-2 decreases whereas Bax, Fas, ICE and ubiquitin modify their pattern of expression in correlation with the changes in apoptotic myonuclei. Apoptosis of endothelial cells is present after the night of wheel-running and with a twofold increase 4 days later (1.5 +/- 2.3 and 4.8 +/- 4.4 P < 0.05, respectively). Satellite cells are also involved in the apoptotic process. Thus, spontaneous running in unaccustomed mice increases the number of apoptotic nuclei in adult muscle fibres and in endothelial cells. It remains to be established whether muscle apoptosis is restricted to the repair mechanisms, as often suggested in many pathologic processes, or it is also part of pathogenesis of muscle damage. Regardless of whether these results are extended to human dystrophies, the clinical implications in terms of secondary pathogenetic mechanisms and muscle training are obvious.
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PMID:Apoptosis of myofibres and satellite cells: exercise-induced damage in skeletal muscle of the mouse. 988 62