Integrin and cell type specific traction force generation and the impact of extrinsic and intrinsic factors

Abstract

We used cell traction force microscopy with micropost arrays, to gain insight into the force generation apparatus of different cell types. Therefore we created micropost arrays made of polydimethylsiloxane and established an own implementation of displacement detection. We compared two different methods and tested the detection accuracy of the method of choice for the later applications. With our established method we performed cell traction force measurements on different cell types and changed several parameters to test the influence on traction forces. Important components of the cell adhesion and migration machinery are the integrins, the actin cytoskeleton and messenger proteins. The analysis of the exact contribution of the individual components of this machinery to cellular properties is hampered by its complexity. Therefore, we reduced the complexity and examined mouse fibroblasts expressing only the fibronectin-binding integrins avb3 or a5b1 or a combination of the two. By manipulating either environmental cues or cell internal parameters we could link the observed effects to the specific integrin type. In addition, we analysed the difference in force generation of two distinct cell lines derived from lung tissue, R3/1 and A549 cells. These are two cells lines that are commonly used as model cells for the alveolar type I and type II cells. Further we analysed the osteocyte-like cell line MLO-Y4. For all cell types we changed intrinsic and extrinsic factors and observed the changes in traction force generation.