Force Transduction In Smooth Muscle Cells

Abstract

Mechanical forces directly affect the form and function of tissues. Transmission of force from outside the cell through focal and junctional adhesions controls the maturation or disassembly of these adhesion sites and initiates intracellular signaling cascades that alter cellular behavior. To understand the mechanism by which living cells sense mechanical forces, and how they respond and adapt to their environment, a critical first step is to develop a new technology able to investigate cellular behavior at sub-cellular level that integrates an atomic force microscope (AFM) with total internal reflection fluorescence (TIRF) microscopy and fast-spinning disk (FSD) confocal microscopy, providing high spatial and temporal resolution. The integrated system is broadly applicable across a wide range of molecular dynamic studies in any adherent live cells, allowing direct optical imaging of cell responses to mechanical stimulation in real-time.Thus, we are able to: (i) image with high spatial resolution or stimulate the apical cell surface using AFM, and (ii) quantitatively time-lapse image the cell-coverslip interface using TIRF, or FSD confocal image to study molecular dynamics and protein translocation between different sub-cellular structures. Significant rearrangement of the actin filaments and focal adhesions was shown due to local mechanical smooth muscle cell stimulation at the apical cell membrane that induced changes into the cellular structure throughout the cell body.By exploring innovative approaches like those used in these investigations, new information for understanding live cell restructuring and dynamics in response to mechanical force can be provided. Understanding how live cells adapt to mechanical force and how they are able to recognize and respond to mechanical stimuli represents an important biophysical problem.