Being out of shape: cell stiffness correlates with actin fiber content rather than cell area

Monday, October 24, 2011 — Poster Session I
Noon – 2:00 p.m.	Natcher Conference Center	NIDCD	BIOPHY-3

* FARE Award Winner

Authors

• N Gavara
• A LaCroix
• V Luo
• R Chadwick

Abstract

Recent studies stressing the effect of geometric cues on cell contractility have brought new interest to the role of cell shape in cellular function. Cell spreading is believed to increase cell stiffness via upregulation of cytoskeleton (CSK) contractility. Previous studies correlated cell stiffness with parameters that were easily measured, such as cell spreading. This was due to the difficulty of measuring cell stiffness and actin fiber content simultaneously in living cells. We have combined live-cell imaging of GFP-actin transfected cells, novel image processing algorithms and Atomic Force Microscopy to assess for the first time the relationship between cell spreading, actin fiber content and cell stiffness. Cell stiffness increased linearly with actin fiber content, but increases were significantly larger for randomly-organized CSKs rather than CSKs with aligned fibers. A CSK with randomly-oriented fibers has more intersecting points between fibers and is likely to be more crosslinked, which provides further mechanical strength to a structure. We also investigated which parameter, cell area or fiber content correlates better with cell stiffness. Our results suggests that cell stiffness correlates with actin fiber content rather than cell area. Our study can reveal the genuine key players on cell mechanics and have implications for cell mechanosensing.

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