September 25, 2009

Grant boosts study of energy-producing mitochondria

Grant boosts study of energy-producing mitochondria

In the movie “Cocoon,” older people regain the vigor of youth when they swim in a pool filled with alien cocoons. That idea, minus the aliens, might not be so far-fetched.

Vanderbilt scientist Deborah Murdock, Ph.D., has received a five-year, $1.8 million “transformative” R01 grant from the National Institutes of Health to answer fundamental questions about mitochondria, which produce energy for the cell, and which are linked to muscle wasting disorders.

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“We lose mitochondria in our muscle as we age,” said Murdock, an investigator in the Center for Human Genetics Research and research assistant professor of Molecular Physiology & Biophysics. “If we could find a way to alleviate that depletion, we might find a way to age better.”

Scientists believe that mitochondria evolved from bacteria to become a specialized cellular subunit responsible for powering the cell and playing a key role in apoptosis, programmed cell death, a key function in multi-cellular organisms.

Bacteria communicate with each other by emitting chemical signals. When enough bacteria are present, reaching what scientists call a “quorum,” the level of chemical signals rises to a point that it triggers the bacteria to begin a coordinated action, such as releasing a toxin.

Murdock wonders if a similar mechanism, which she calls “mitochondrial quorum sensing,” is used by mitochondria to regulate their numbers in response to energy requirements of various tissues and organs in the body.

If so, and if the molecules by which mitochondria communicate could be identified, then scientists might be able to develop a drug that triggers mitochondrial expansion “so you wouldn’t have muscle wasting in an older person,” she said.

Murdock’s co-investigator on the grant is David Samuels, Ph.D., associate professor of Molecular Physiology & Biophysics.