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Development-dependent disappearance of caspase-3 in skeletal muscle is post-transcriptionally regulated
Louis-Bruno Ruest1, Abdelnaby Khalyfa, Eugenia Wang
1Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital and Department of Medicine, McGill University, Montreal, Quebec, Canada.
Abstract:
Caspase-3, a major player in apoptosis, engages apoptosis-activated cells into an irreversible pathway leading to cell death. In this article, we report that caspase-3 protein is absent from rat and mouse adult skeletal muscles, despite the abundant presence of its mRNA. During skeletal muscle development, caspase-3 protein is present in neonatal animals, but its expression gradually decreases, and disappears completely by 1 month of age, when there is still abundant caspase-3 mRNA. This discordance between caspase-3 message and protein expression is unique to skeletal muscle, as in all other analyzed tissues the protein presence correlates with the presence of the mRNA. The only circumstance in which caspase-3 protein appears in adults is in regenerating muscles; once regeneration is complete, however, it again becomes undetectable in repaired muscles. We conclude that caspase-3 protein in skeletal muscle is uniquely regulated at the post-transcriptional level, unseen in other tissues such as brain, heart, lung, kidney, thymus, spleen, liver, or testis. The post-transcriptional regulation of caspase-3 might serve as a fail-safe mechanism to avoid accidental cell death.
Insights
Caspase-3 protein is absent in adult skeletal muscles, despite abundant mRNA. This unique post-transcriptional regulation in muscle may prevent accidental cell death.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Caspase-3 is a key executioner of apoptosis, initiating programmed cell death.
- Apoptosis is crucial for development and tissue homeostasis.
- Dysregulation of apoptosis can lead to various diseases.
Purpose of the Study:
- To investigate the expression and regulation of caspase-3 protein in adult skeletal muscle.
- To determine if caspase-3 regulation differs between skeletal muscle and other tissues.
- To explore the potential functional significance of caspase-3 regulation in skeletal muscle.
Main Methods:
- Analysis of caspase-3 mRNA and protein levels in rat and mouse skeletal muscle at different developmental stages and in adult tissues.
- Comparison of caspase-3 expression patterns in skeletal muscle with other major organs (brain, heart, lung, kidney, thymus, spleen, liver, testis).
- Investigation of caspase-3 protein presence in regenerating skeletal muscle.
Main Results:
- Caspase-3 protein is absent in adult rat and mouse skeletal muscles, contrasting with abundant caspase-3 mRNA.
- During development, caspase-3 protein is present in neonatal muscle but disappears by one month of age, while mRNA remains.
- Caspase-3 protein reappears in regenerating muscle but is again undetectable after repair, a pattern unique to skeletal muscle.
Conclusions:
- Skeletal muscle uniquely regulates caspase-3 protein at the post-transcriptional level, unlike other tissues where mRNA and protein levels correlate.
- This unique regulation may function as a safeguard against unintended apoptosis in skeletal muscle.
- Understanding this mechanism could offer insights into muscle physiology and disease.