Dynamic crosstalk between cytoskeletal filaments regulates dorsoventral cytoplasmic mechanics

The cytoplasm exhibits viscoelastic properties, displaying both solid and liquid-like behaviour, and can actively regulate its mechanical attributes. The cytoskeleton is a major regulator among the numerous factors influencing cytoplasmic mechanics. We explore the interdependence of various cytoskeletal filaments and the impact of their density on cytoplasmic viscoelasticity. The heterogeneous distribution of these filaments gives rise to polarised mechanical properties of the cytoplasm along the dorsoventral axis. Actin filament disassembly softens the ventral cytoplasm while stiffening the mid cytoplasm, due to increased vimentin filament assembly. Disruption of microtubules or depletion of vimentin softens both the ventral and mid cytoplasm. Cytochalasin D (Cyto D) treatment results in a localised increase of vimentin assembly in the mid cytoplasm, which is dependent on the cytolinker plectin. Nocodazole treatment has a negligible effect on F-actin distribution but significantly alters the spatial arrangement of vimentin. We demonstrate that Cyto D treatment upregulates vimentin expression via reactive oxygen species-mediated activation of NF-κΒ. This article investigates how different cytoskeletal filaments influence the rheological characteristics of various cytoplasmic regions.