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Updated: Sep 23, 2025
05:58
Tissue Triage and Freezing for Models of Skeletal Muscle Disease
Published on: July 15, 2014
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A pathogenic mechanism associated with myopathies and structural birth defects involves TPM2-directed myogenesis
Jennifer McAdow1, Shuo Yang1, Tiffany Ou1
1Department of Developmental Biology, Washington University in St. Louis, St. Louis, Missouri, USA.
JCI Insight
|May 17, 2022
Summary
Pathogenic variants in Tropomyosin 2 (TPM2) cause muscle disorders. This study reveals disrupted myogenesis as a novel mechanism and demonstrates that zebrafish assays can predict disease severity in patients.
Area of Science:
- Genetics
- Molecular Biology
- Developmental Biology
Background:
- Nemaline myopathy (NM) is a congenital myopathy caused by genetic variants.
- Tropomyosin 2 (TPM2) variants lead to a range of musculoskeletal disorders, including NM and distal arthrogryposis (DA).
- The in vivo mechanisms of TPM2-related disorders remain largely unknown.
Purpose of the Study:
- To investigate the in vivo pathomechanisms of TPM2-related musculoskeletal disorders.
- To establish and validate myogenic assays for predicting clinical severity.
Main Methods:
- Expressed dominant pathogenic TPM2 variants in Drosophila embryos.
- Performed transient overexpression assays in mouse myotubes (in vitro) and zebrafish (in vivo).
- Characterized TPM2 variants identified in patients with distal arthrogryposis (DA).
Main Results:
- Four TPM2 variants significantly impaired muscle development and function in Drosophila.
- Overexpression of pathogenic TPM2 variants disrupted mouse myotube morphogenesis and zebrafish muscle development.
- Zebrafish assays with novel and recurring TPM2 variants mirrored patient-observed musculoskeletal defects.
Conclusions:
- Disrupted myogenesis is a potential novel pathomechanism in TPM2 disorders.
- Myogenic assays in model organisms can predict the clinical severity of TPM2 variants.
- This research provides insights into the molecular basis of congenital myopathies and related disorders.
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