Mutation in the Core Structure of Desmin Intermediate Filaments Affects Myoblast Elasticity.

Elastic properties of cells are mainly derived from the actin cytoskeleton. However, intermediate filaments are emerging as major contributors to the mechanical properties of cells. Using atomic force microscopy, we studied the elasticity of mouse myoblasts expressing a mutant form of the gene encoding for desmin intermediate filaments, p.D399Y. This variant produces desmin aggregates, the main pathological symptom of myofibrillar myopathies. Here we show that desmin-mutated cells display a 39% increased median elastic modulus compared to wild-type cells. Desmin-mutated cells required higher forces than wild-type cells to reach high indentation depths, where desmin intermediate filaments are typically located. In addition, heat-shock treatment increased the proportion of cells with aggregates and induced a secondary peak in the distribution of Young's moduli. By performing atomic force microscopy mechanical mapping combined with fluorescence microscopy, we show that higher Young's moduli were measured where desmin aggregates were located, indicating that desmin aggregates are rigid. Therefore, we provide evidence that p.D399Y stiffens mouse myoblasts. Based on these results, we suggest that p.D399Y-related myofibrillar myopathy is at least partly due to altered mechanical properties at the single-cell scale, which are propagated to the tissue scale. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Citation

Catherine Even, Gilles Abramovici, Florence Delort, Anna F Rigato, Virginie Bailleux, Abel de Sousa Moreira, Patrick Vicart, Felix Rico, Sabrina Batonnet-Pichon, Fatma Briki. Mutation in the Core Structure of Desmin Intermediate Filaments Affects Myoblast Elasticity. Biophysical journal. 2017 Aug 08;113(3):627-636

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PMID: 28793217

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