Probing effects of vimentin on cell cytoskeleton dynamics through Differential Dynamic Microscopy (DDM)

The cell cytoskeleton is a complex network of actin, microtubules, and intermediate filaments, which play a fundamental role in various cellular processes, such as cell polarization, intracellular transport, and cell migration. While microtubules are central to cell-polarization and have been studied in great detail, vimentin intermediate filaments also seem to play a role, as disrupting vimentin impairs polarized cell motion and the directional mobility of vesicles. In our investigation, we employed Differential Dynamic Microscopy (DDM) to explore the dynamic behavior of the microtubules and vesicles in wild-type and vimentin-null mouse embryonic fibroblasts. Here, we measured the dynamics and spatial organization of microtubule network using DDM in presence and absence of vimentin. Our research reveals that cells lacking vimentin show 1.5 times higher decay times compared to cells with vimentin, which suggest that vimentin enhances the dynamics of microtubule filaments in the cell. Furthermore, Fluorescence Recovery after Photobleaching studies indicate that, despite an equivalent tubulin concentration in both wild-type (WT) and vimentin-null (VN) cells, the rate of fluorescence recovery is higher in cells with vimentin. Our results indicate a role of vimentin in mediating microtubule dynamics, which has important implications for how cells organize and coordinate polarized motion.