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Updated: Aug 29, 2026
CRISPR/Cas9 Technology in Restoring Dystrophin Expression in iPSC-Derived Muscle Progenitors
Published on: September 14, 2019
Stimulation of calcineurin signaling attenuates the dystrophic pathology in mdx mice
Joe V Chakkalakal1, Mary-Ann Harrison, Salvatore Carbonetto
1Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
Abstract:
Utrophin has been studied extensively in recent years in an effort to find a cure for Duchenne muscular dystrophy. In this context, we previously showed that mice expressing enhanced muscle calcineurin activity (CnA*) displayed elevated levels of utrophin around their sarcolemma. In the present study, we therefore crossed CnA* mice with mdx mice to determine the suitability of elevating calcineurin activity in preventing the dystrophic pathology. Muscles from mdx/CnA* displayed increased nuclear localization of NFATc1 and a fiber type shift towards a slower phenotype. Measurements of utrophin levels in mdx/CnA* muscles revealed an approximately 2-fold induction in utrophin expression. Consistent with this induction, we also observed that members of the dystrophin-associated protein (DAP) complex were present at the sarcolemma of mdx/CnA* mouse muscle. This restoration of the utrophin-DAP complex was accompanied by significant reductions in the extent of central nucleation and fiber size variability. Importantly, assessment of myofiber sarcolemmal damage, as monitored by the intracellular presence of IgM and albumin as well as by Evans blue uptake in vivo, revealed a net amelioration of membrane integrity. Finally, immunofluorescence experiments using Mac-1 antibodies showed a reduction in the number of infiltrating immune cells in muscles from mdx/CnA* mice. These results show that elevated calcineurin activity attenuates the dystrophic pathology and thus provides an effective target for pharmacological intervention.
Insights
Elevating calcineurin activity in mice with Duchenne muscular dystrophy (mdx) increased utrophin levels, reduced muscle damage, and improved membrane integrity, suggesting a potential therapeutic target.
Area of Science:
- Muscle Physiology
- Molecular Biology
- Genetics
Background:
- Duchenne muscular dystrophy (DMD) is a severe genetic disorder.
- Utrophin is a protein investigated as a potential therapeutic for DMD.
- Enhanced calcineurin activity (CnA*) in mice was previously shown to increase utrophin levels.
Purpose of the Study:
- To investigate if elevated calcineurin activity can prevent dystrophic pathology in mdx mice.
- To assess the therapeutic potential of targeting calcineurin for DMD treatment.
Main Methods:
- Crossed CnA* mice with mdx mice (mdx/CnA*).
- Measured utrophin levels, NFATc1 localization, and fiber type.
- Assessed sarcolemmal damage using IgM, albumin, and Evans blue uptake.
- Quantified immune cell infiltration with Mac-1 antibodies.
Main Results:
- mdx/CnA* mice showed a 2-fold increase in utrophin expression.
- Restoration of the dystrophin-associated protein (DAP) complex at the sarcolemma.
- Significant reduction in central nucleation and fiber size variability.
- Amelioration of myofiber sarcolemmal damage and reduced immune cell infiltration.
Conclusions:
- Elevated calcineurin activity effectively attenuates dystrophic pathology in mdx mice.
- Targeting calcineurin activity represents a promising strategy for pharmacological intervention in DMD.
