Examining Integrated Cell Structural Responses: Probing Cytoskeleton Behavior through a Coupled Dual-Mode Mechanical Stimulation Approach

Abstract

Mechanical stimulation of cells has been shown to affect various cellular functions through the actin cytoskeleton such as cell motility, apoptosis, and proliferation. The influence of mechanics on cells is evident whether the stimulation is in the form of tension, compression, or even shear stress. In this there is a need to influence cellular function through its extracellular matrix connections with multiple integrated mechanical approaches to gain a better understanding in the field of mechanotransduction. In this study we developed a device that when utilized with an elastomeric material allows us to stimulate cells with uniaxial strip stretching, shear fluid flow or both simultaneously. This device uses a pressure regulator to induce uniaxial strip stress along the basal surface of cells and a peristaltic flow pump to induce shear stress across the apical surface. We exposed NIH/3T3 fibroblasts to uniaxial strip stretching, shear fluid flow and both simultaneously to examine the question of how the integrated inputs of mechanical stimulation are processed by the cell in terms of its structural response. We used fluorescence microscopy to examine the orientation of F-actin and G-actin structures and found alignment along the direction of force for both uniaxial strip stretching and shear fluid flow in comparison to cells exposed to both mechanical modes, which revealed an alignment out of phase between both axes of applied force. This integrated response is helping to discern the influence of the modes of stimulation in terms of overall cell behavior. These intriguing results have potential implications in a variety of fields including biophysics, mechanotransduction, and cell structure.