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Updated: Aug 15, 2026
Immunolabelling Myofiber Degeneration in Muscle Biopsies
Published on: December 5, 2019
Increased expression of deltaCaMKII isoforms in skeletal muscle regeneration: Implications in dystrophic muscle
S Thomas Abraham1, Carisa Shaw
1Department of Pharmaceutical Sciences, Campbell University School of Pharmacy, PO 1090, Buies Creek, NC 27529, USA. abraham@campbell.edu
Abstract:
The expression of delta isoforms of calcium-calmodulin/dependent protein kinase II (CaMKII) has been reported in mammalian skeletal muscle; however, their functions in this tissue are largely unknown. This study was conducted to determine if deltaCaMKII expression was altered during regeneration of skeletal muscle fibers in two distinct models. In the first model, necrosis and regeneration were induced in quadriceps of normal mice by intramuscular administration of 50% glycerol. Immunostaining and confocal microscopy revealed that deltaCaMKII expression was clearly enhanced in fibers showing centralized nuclei. The second model was the mdx mouse, which undergoes enhanced muscle necrosis and regeneration due to a mutation in the dystrophin gene. sern blot analysis of hind leg extracts from 4 to 6 week old mdx mice revealed that deltaCaMKII content was decreased when compared to age-matched control mice. This loss in delta kinase content was seen in myofibrillar and membrane fractions and was in contrast to unchanged deltaCaMKII levels in cardiac and brain extracts from dystrophic mice. Confocal microscopy of mdx quadriceps and tibialis muscle showed that deltaCaMKII expression was uniformly decreased in most fibers from dystrophic mice; however, enhanced kinase expression was observed in regenerating muscle fibers. These data support a fundamental role for deltaCaMKII in the regeneration process of muscle fibers in normal and mdx skeletal muscle and may have important implications in the reparative process following muscle death.
Insights
Delta CaMKII expression is altered during skeletal muscle regeneration. This protein is enhanced in regenerating fibers in normal mice and in mdx mice, suggesting a role in muscle repair.
Area of Science:
- Muscle physiology and regeneration
- Molecular biology of muscle repair
- Calcium-calmodulin/dependent protein kinase II (CaMKII) signaling
Background:
- Delta isoforms of CaMKII are present in mammalian skeletal muscle, but their specific functions remain largely uncharacterized.
- Skeletal muscle regeneration is a complex process involving the repair of damaged muscle fibers.
Purpose of the Study:
- To investigate the expression patterns of deltaCaMKII during skeletal muscle regeneration in two distinct mouse models.
- To determine the role of deltaCaMKII in the regenerative processes of normal and dystrophic skeletal muscle.
Main Methods:
- Induction of muscle necrosis and regeneration using glycerol in normal mouse quadriceps.
- Analysis of mdx mice, a model for Duchenne muscular dystrophy, exhibiting enhanced muscle regeneration.
- Utilized immunostaining, confocal microscopy, and Western blot analysis to assess deltaCaMKII expression levels and localization.
Main Results:
- DeltaCaMKII expression was significantly enhanced in regenerating muscle fibers with centralized nuclei in normal mice.
- Western blot analysis revealed decreased deltaCaMKII content in myofibrillar and membrane fractions of mdx mouse hind leg extracts compared to controls.
- While overall deltaCaMKII levels were reduced in mdx mice, enhanced expression was observed in regenerating muscle fibers within these mice.
Conclusions:
- Delta CaMKII plays a fundamental role in the regeneration of skeletal muscle fibers in both normal and mdx mouse models.
- The findings suggest that deltaCaMKII is involved in the reparative processes following muscle injury and degeneration.
- Understanding deltaCaMKII's role may offer insights into therapeutic strategies for muscle-related disorders.
