Programmed cell death contributes force to the movement of cells

Sep 18, 2008

In addition to pruning cells out of the way during embryonic development, the much-studied process of programmed cell death, or apoptosis, has been newly found to exert significant mechanical force on surrounding cells.

This mechanical force may be harnessed throughout biology by tissues to aid wound formation, organ development and other processes that require cell movement, according to a Duke University team that melds biology with physics to investigate force at the cellular level.

Cells are known to move in coordinated fashion during the closure of an eye-shaped opening on the back of a developing fruit fly embryo, a model system Duke biophysicists have been working on for nearly a decade. Duke biology chair Dan Kiehart likens this dorsal closure event to drawing the strings on a sleeping bag.

The newly discovered force created by apoptotic cells imploding and withdrawing "is making a force sort of like a friend helping you tuck the edge of the sleeping bag in," Kiehart said.

Dying cells appear to occur at random times across the plane of cells comprising the shrinking opening, in a pattern that totals about 10 percent of the population of cells. When Kiehart first observed them in 2000, he thought "well if it's only 10 percent, I can ignore it."

Physics post-doctoral researcher Yusuke Toyama thought that the apoptotic cells might be particularly significant for force production. Toyama, who's training started in particle physics but has moved toward biology, began carefully measuring the motion of cells immediately surrounding a dying cell.

What he saw through the microscope, by laser-induced fluorescence, was that as a dying cell collapsed and sunk beneath the surface, it contributed to the forces pulling the edges of the opening closer together.

"So apoptosis is not a single cell event but is amplified by the five-to-seven surrounding cells," Toyama said.

On balance, these dying cells exert perhaps a third to a half of the force that is moving the edges of the opening together, so it's a very significant part of the process, said Glenn Edwards, professor of physics and director of Duke's Free Electron Laser Lab. "The forces at work here are measured in perhaps billionths of a Newton, but that's because you're moving cells," Edwards said. At the cellular scale, these forces are quite substantial.

The group's findings appear in the Sept. 19 edition of Science. Funding for the research was provided by the National Institutes of Health.

Though this finding is so far limited to dorsal closure in the fruit fly embryo, Edwards and Kiehart are going to begin looking for the mechanical force of apoptosis elsewhere. Their earlier findings on the fruit fly model so far have appeared applicable to wound closure and organ development in vertebrates like humans.

It's entirely possible, Kiehart said, that evolution has harnessed the mechanical force created by dying cells in many other ways. "In evolution, biology uses what is available to it."

Source: Duke University

Explore further: A cost-effective method uses fungi to convert palm oil waste to green products

add to favorites email to friend print save as pdf

Related Stories

Skeleton of cells controls cell multiplication

Feb 26, 2015

A research team from Instituto Gulbenkian de Ciencia (IGC; Portugal), led by Florence Janody, in collaboration with Nicolas Tapon from London Research Institute (LRI; UK), discovered that the cell's skeleton ...

Voltage tester for beating cardiac cells

Feb 17, 2015

For the first time, scientists have succeeded in recording the current in membrane channels of contracting cardiac cells. To do this, the scientists combined an atomic force microscope with a widely used ...

Recommended for you

Metabolic path to improved biofuel production

15 minutes ago

Researchers with the Energy Biosciences Institute (EBI), a partnership that includes the Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, have found a way ...

Deadly frog fungus dates back to 1880s, studies find

2 hours ago

A deadly fungus responsible for the extinction of more than 200 amphibian species worldwide has coexisted harmlessly with animals in Illinois and Korea for more than a century, a pair of studies have found.

Wild yaks: Shaggy barometers of climate change

3 hours ago

A new study led by WCS (Wildlife Conservation Society), University of Montana, Qinghai Forestry Bureau, Keke Xili National Nature Reserve, and other groups finds that climate change and past hunting in the ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.