Mechanical and morphological response of confluent epithelial cell layers to reinforcement and dissolution of the F-actin cytoskeleton

Abstract

The F-actin cytoskeleton and its connection to the plasma membrane provide structure and shape of epithelial cells. In this study we focus on the impact of the F-actin cytoskeleton on the morphology and mechanical behaviour of confluent epithelial cells. F-actin depolymerisation was fostered by Latrunculin A, while depolymerisation was allayed by Jasplakinolide. The impact of drug treatment on cellular mechanics was measured using atomic force microscopy based active microrheology and force-indentation curves, while morphology was monitored by AFM imaging, electric cell-substrate impedance sensing (ECIS) experiments and fluorescence microscopy. A softening and fluidisation of the cells upon dissolution of F-actin was observed, accompanied by reduction of cell-substrate and cell-cell contacts and an altered topography. The strengthening of actin filaments upon Jasplakinolide treatment was mirrored in several mechanical properties. The largest impact was on the cellular viscosity. The cells were, however, capable of restoring their initial phenotypes, e.g., amount of actin, intercellular and cell-substrate interactions.

Keywords: AFM; Actin; Cell mechanics; Cytoskeleton affecting drugs; Microrheology; Tension.