Nuclear Stress-Strain State over Micropillars: A Mechanical In silico Study

Cells adapt to their environment and stimuli of different origin. During confined migration through sub-cellular and sub-nuclear pores, they can undergo large strains and the nucleus, the most voluminous and the stiffest organelle, plays a critical role. Recently, patterned microfluidic devices have been employed to analyze the cell mechanical behavior and the nucleus self-deformations. In this paper, we present an in silico model to simulate the interactions between the cell and the underneath microstructured substrate under the effect of the sole gravity. The model lays on mechanical features only and it has the potential to assess the contribution of the nuclear mechanics on the cell global behavior. The cell is constituted by the membrane, the cytosol, the lamina, and the nucleoplasm. Each organelle is described through a constitutive law defined by specific mechanical parameters, and it is composed of a fluid and a solid phase leading to a viscoelastic behavior. Our main objective is to evaluate the influence of such mechanical components on the nucleus behavior. We have quantified the stress and strain distributions in the nucleus, which could be responsible of specific phenomena such as the lamina rupture or the expression of stretch-sensitive proteins.