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Fiber Type and Subcellular-Specific Analysis of Lipid Droplet Content in Skeletal Muscle
Published on: June 8, 2022
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Lipid accumulation in dysferlin-deficient muscles
Miranda D Grounds1, Jessica R Terrill1, Hannah G Radley-Crabb2
1Schools of Anatomy, Physiology and Human Biology, University of Western Australia, Perth, Australia.
The American Journal of Pathology
|April 2, 2014
Summary
Dysferlin deficiency causes lipid droplet accumulation and adipocyte replacement in muscles, leading to progressive myopathy. This study reveals early lipogenesis induction, offering new insights into dysferlinopathy mechanisms.
Area of Science:
- Muscle biology
- Cellular pathology
- Biochemistry
Background:
- Dysferlin is a membrane protein crucial for vesicle trafficking and fusion.
- Dysferlin defects cause limb-girdle muscular dystrophy type 2B and Miyoshi myopathy in humans and mice.
- The underlying pathomechanism of dysferlin-related myopathies remains unclear.
Purpose of the Study:
- To investigate the pathomechanism of muscle dysfunction in dysferlin-deficient individuals.
- To identify early molecular events preceding muscle pathology in dysferlinopathies.
- To explore the role of dysferlin in lipid metabolism and adipogenesis within muscle.
Main Methods:
- Oil Red O staining to detect lipid droplets in muscle tissues.
- Electron microscopy to examine myofiber architecture and cellular changes.
- Quantitative real-time PCR to assess gene expression related to lipogenesis.
Main Results:
- Dysferlin-deficient mice (A/J(dys-/-) and BLAJ) and human patients exhibited significant lipid droplet accumulation within myofibers.
- Electron microscopy revealed disturbed myofiber architecture and increased adipocyte presence in affected muscles.
- Early upregulation of CCAAT/enhancer binding protein-δ mRNA was observed in dysferlin-deficient muscles, indicating early lipogenesis induction.
Conclusions:
- Dysferlin deficiency is associated with widespread lipid accumulation and adipocyte infiltration in muscles.
- Early lipogenesis and adipogenesis are key events in the progression of dysferlinopathy.
- These findings provide a new framework for understanding and potentially treating dysferlinopathies.
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