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A mechanochemical model of cell reorientation on substrates under cyclic stretch.

Qian J, Liu H, Lin Y, Chen W, Gao H - PLoS ONE (2013)

Bottom Line: We report a theoretical study on the cyclic stretch-induced reorientation of spindle-shaped cells.Our main hypothesis is that cells tend to orient in the direction where the formation of stress fibers is energetically most favorable.This theory also provides a simple explanation on the regulation of protein Rho in the formation of stretch-induced stress fibers in cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering Mechanics, Soft Matter Research Center, Zhejiang University, Hangzhou, Zhejiang, China.

ABSTRACT
We report a theoretical study on the cyclic stretch-induced reorientation of spindle-shaped cells. Specifically, by taking into account the evolution of sub-cellular structures like the contractile stress fibers and adhesive receptor-ligand clusters, we develop a mechanochemical model to describe the dynamics of cell realignment in response to cyclically stretched substrates. Our main hypothesis is that cells tend to orient in the direction where the formation of stress fibers is energetically most favorable. We show that, when subjected to cyclic stretch, the final alignment of cells reflects the competition between the elevated force within stress fibers that accelerates their disassembly and the disruption of cell-substrate adhesion as well, and an effectively increased substrate rigidity that promotes more stable focal adhesions. Our model predictions are consistent with various observations like the substrate rigidity dependent formation of stable adhesions and the stretching frequency, as well as stretching amplitude, dependence of cell realignment. This theory also provides a simple explanation on the regulation of protein Rho in the formation of stretch-induced stress fibers in cells.

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Steady state bond density as a function of substrate rigidity.
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pone-0065864-g004: Steady state bond density as a function of substrate rigidity.

Mentions: Let's first neglect any externally applied stretch, correspondingly , and investigate how cells sense and respond to substrate stiffness on their own contractility (described by ) through the competing process between formation and disruption of FAs and SFs in our modeling framework. From Eq. (11), it is clearly seen that the steady state solution is(12)Plotted in Fig. 4 is as a function of for estimated values of , a and in Table 1. Obviously, and hence decrease exponentially as the substrate, or more precisely the bond-substrate system, becomes more compliant, in qualitative agreement with Saez et al. [65] showing that the traction forces developed by cells increase as the substrate becomes more rigid. Physically, this can be understood by realizing that the strain energy stored, or equivalently the amount of energy cells need to invest, in the bond on a softer substrate is higher than that on a more rigid, which makes the formation of bonds on softer substrates more energy-consuming.


A mechanochemical model of cell reorientation on substrates under cyclic stretch.

Qian J, Liu H, Lin Y, Chen W, Gao H - PLoS ONE (2013)

Steady state bond density as a function of substrate rigidity.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3675090&req=5

pone-0065864-g004: Steady state bond density as a function of substrate rigidity.
Mentions: Let's first neglect any externally applied stretch, correspondingly , and investigate how cells sense and respond to substrate stiffness on their own contractility (described by ) through the competing process between formation and disruption of FAs and SFs in our modeling framework. From Eq. (11), it is clearly seen that the steady state solution is(12)Plotted in Fig. 4 is as a function of for estimated values of , a and in Table 1. Obviously, and hence decrease exponentially as the substrate, or more precisely the bond-substrate system, becomes more compliant, in qualitative agreement with Saez et al. [65] showing that the traction forces developed by cells increase as the substrate becomes more rigid. Physically, this can be understood by realizing that the strain energy stored, or equivalently the amount of energy cells need to invest, in the bond on a softer substrate is higher than that on a more rigid, which makes the formation of bonds on softer substrates more energy-consuming.

Bottom Line: We report a theoretical study on the cyclic stretch-induced reorientation of spindle-shaped cells.Our main hypothesis is that cells tend to orient in the direction where the formation of stress fibers is energetically most favorable.This theory also provides a simple explanation on the regulation of protein Rho in the formation of stretch-induced stress fibers in cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering Mechanics, Soft Matter Research Center, Zhejiang University, Hangzhou, Zhejiang, China.

ABSTRACT
We report a theoretical study on the cyclic stretch-induced reorientation of spindle-shaped cells. Specifically, by taking into account the evolution of sub-cellular structures like the contractile stress fibers and adhesive receptor-ligand clusters, we develop a mechanochemical model to describe the dynamics of cell realignment in response to cyclically stretched substrates. Our main hypothesis is that cells tend to orient in the direction where the formation of stress fibers is energetically most favorable. We show that, when subjected to cyclic stretch, the final alignment of cells reflects the competition between the elevated force within stress fibers that accelerates their disassembly and the disruption of cell-substrate adhesion as well, and an effectively increased substrate rigidity that promotes more stable focal adhesions. Our model predictions are consistent with various observations like the substrate rigidity dependent formation of stable adhesions and the stretching frequency, as well as stretching amplitude, dependence of cell realignment. This theory also provides a simple explanation on the regulation of protein Rho in the formation of stretch-induced stress fibers in cells.

Show MeSH
Related in: MedlinePlus