Apico-basal cell compression regulates Lamin A/C levels in Epithelial tissues

Abstract

Nuclear lamina bridges mechanical forces from the cytoskeleton to the nucleus, to initiate nuclear mechanotransduction. The concentration of nuclear Lamin proteins, particularly Lamin A/C is crucial for the mechanical properties of the nucleus and nuclear mechanotransduction. Recent studies in mesenchymal tissues show that the concentration of Lamin A/C scales with stiffness and concentration of the underlying extracellular matrix (ECM). But in epithelial tissues, that lack a strong cell-ECM interaction, it is still unclear how Lamin A/C is regulated. Here, we show that concentration of Lamin A/C in epithelial tissues scales with apico-basal compression of cells and is independent of ECM concentration. But, ectopically altering the concentration of Lamin A/C does not influence cell shapes in epithelial tissues. Using genetic perturbations in Drosophila epithelial tissues, we reveal that apico-basal cell compression regulates the concentration of Lamin A/C by deforming the nucleus. We observe a similar mechanism of Lamin A/C regulation in mammalian Madin Darby Canine Kidney (MDCK) cells suggesting that this mechanism is evolutionarily conserved. Taken together, our results reveal a unidirectional mechanical coupling between cell mechanics and nuclear mechanics via the regulation of Lamin A/C. We anticipate that mechanism of Lamin A/C regulation that we revealed, could form the basis for understanding nuclear mechanotransduction in epithelial tissues.