Enhanced cell viscosity : a new phenotype associated with lamin A/C alterations

Lamin A/C is a key player in the stability and rigidity of the cell nucleus. As a result, mutations in this protein can lead to diseases known as laminopathies. One family of laminopathies, in particular, causes symptoms of premature aging, such as Progeria, which leads to premature aging of the entire organism. We have performed microfluidic experiments to measure the mechanical properties of cells and study the impact of alterations in lamin A/C, induced either artificially by a biochemical treatment or by a genetic mutation in lamin A/C associated with the laminopathy called lipodystrophy, which disorganizes adipose tissues and leads, among other things, to cardiovascular problems. Our measurements reveal an increase in cell viscosity in both cases of alterations, driven not only by alterations in the nucleus itself but also by its links with the cell cytoskeleton, and especially with the microtubule cytoskeleton. This change in viscosity could be a marker of lamin A/C alterations, and our microfluidic assay could therefore serve as a diagnostic tool for lamin A/C-related diseases.