Monday, June 20, 2005
Boston, MA - An international team led by Jeffrey J. Fredberg, professor of bioengineering
and physiology at the Harvard School of Public Health, has found that the cell
modulates its mechanical properties in much the same way as a glassblower shapes
fine glassware. This new view of cellular functions sheds light on mechanical
facets of phenomena as diverse as asthma, cancer, inflammation, and vascular
disease. These findings appear in advance online from the July, 2005 issue of Nature
Materials ( http://www.nature.com/nmat/index.html ).
To fashion a work of glass, a glassblower must heat
the object, shape it, and then cool it down. Fredberg
and his colleagues have shown that the cell modulates
its mechanical properties and changes its malleability in much the same way.
But instead of changing temperature, the cell changes a temperature-like property
that has much the same effect.
Using an array of novel nanotechnologies developed by the researchers at HSPH,
Fredberg et al. discovered the basic physical laws that describe cell
mechanical behavior. Previously, the classical model of cell mechanical
behavior had pictured the cell as a viscous fluid core contained by an elastic
cortical membrane, but their findings did not at all conform to that picture.
The team's experiments show that the cell is a strange intermediate form of matter
that is neither solid nor fluid, but retains features of both. Moreover, as the
cell goes about its routine business of stretching, spreading, and contracting,
it can vary that temperature-like property and control where it sits along the
spectrum between solid-like and fluid-like states.
"These findings have important lessons for understanding the dynamics of structural
proteins at a scale that is intermediate between the single molecule and integrative
cellular function. This is a collective phenomenon of many molecules interacting
in concert, and would disappear altogether in the study of one molecule interacting
with another in isolation," said Fredberg. He continued, "The laws governing
cell behavior bring together into one physical picture cell elasticity, viscosity,
and remodeling, and give us a different way to think about the molecular basis
of airway narrowing in asthma, vessel narrowing in vascular disease, wound repair,
embryonic development, and cell invasion in cancer, all of which have important
mechanical components. Perhaps most surprising of all, in addition to offering
a different way to think about mechanisms of disease, these findings shed light
upon the behavior of familiar inert condensed substances that remain poorly understood,
including pastes, foams, emulsions, and granular materials."
The research was supported by grants from the National Institutes of Health.
Christina Roache (617) 432-6052
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Boston, MA 02115
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