How work tells muscles to grow

Jan 03, 2012

We take it for granted, but the fact that our muscles grow when we work them makes them rather unique. Now, researchers have identified a key ingredient needed for that bulking up to take place. A factor produced in working muscle fibers apparently tells surrounding muscle stem cell "higher ups" that it's time to multiply and join in, according to a study in the January Cell Metabolism, a Cell Press journal.

In other words, that so-called serum response factor (Srf) translates the mechanical signal of work into a chemical one.

"This signal from the muscle fiber controls stem and participation in muscle growth," says Athanassia Sotiropoulos of Inserm in France. "It is unexpected and quite interesting." It might also lead to new ways to combat .

Sotiropoulos' team became interested in Srf's role in muscle in part because their earlier studies in mice and humans showed that Srf concentrations decline with age. That led them to think Srf might be a culprit in the muscle atrophy so common in aging.

The new findings support that view, but Srf doesn't work in the way the researchers had anticipated. Srf was known to control many other genes within muscle fibers. That Srf also influences the activities of the satellite stem cells came as a surprise.

Mice with lacking Srf are no longer able to grow when they are experimentally overloaded, the new research shows. That's because don't get the message to proliferate and fuse with those pre-existing myofibers.

Srf works through a network of genes, including one known as . That raises the intriguing possibility that commonly used Cox2 inhibitors—think ibuprofen—might work against muscle growth or recovery, Sotiropoulos notes.

Treatments designed to tweak this network of factors might be used to wake muscle stem cells up and enhance muscle growth in circumstances such as aging or following long periods of bed rest, she says. Most likely, such therapies would be more successfully directed not at Srf itself, which has varied roles, but at its targets.

"It may be difficult to find a beneficial amount of Srf," she says. "Its targets, interleukins and prostaglandins, may be easier to manipulate."

Explore further: Cell division speed influences gene architecture

More information: Guerci et al.: "Srf-dependent paracrine signals produced by myofibers control satellite cell-mediated skeletal muscle hypertrophy."

add to favorites email to friend print save as pdf

Related Stories

New clues about the basis of muscle wasting disease

Mar 12, 2010

New findings that shed light on how genetic damage to muscle cell proteins can lead to the development of the rare muscle-wasting disease, nemaline myopathy, are reported today (15 March) in the Biochemical Journal.

Team identifies stem cells that repair injured muscles

Mar 05, 2009

A University of Colorado at Boulder research team has identified a type of skeletal muscle stem cell that contributes to the repair of damaged muscles in mice, which could have important implications in the treatment of injured, ...

Recommended for you

Cell division speed influences gene architecture

20 hours ago

Speed-reading is a technique used to read quickly. It involves visual searching for clues to meaning and skipping non-essential words and/ or sentences. Similarly to humans, biological systems are sometimes ...

Secret life of cells revealed with new technique

22 hours ago

(Phys.org) —A new technique that allows researchers to conduct experiments more rapidly and accurately is giving insights into the workings of proteins important in heart and muscle diseases.

In the 'slime jungle' height matters

23 hours ago

(Phys.org) —In communities of microbes, akin to 'slime jungles', cells evolve not just to grow faster than their rivals but also to push themselves to the surface of colonies where they gain the best access ...

Queuing theory helps physicist understand protein recycling

Apr 22, 2014

We've all waited in line and most of us have gotten stuck in a check-out line longer than we would like. For Will Mather, assistant professor of physics and an instructor with the College of Science's Integrated Science Curriculum, ...

User comments : 0

More news stories

When things get glassy, molecules go fractal

Colorful church windows, beads on a necklace and many of our favorite plastics share something in common—they all belong to a state of matter known as glasses. School children learn the difference between ...

SK Hynix posts Q1 surge in net profit

South Korea's SK Hynix Inc said Thursday its first-quarter net profit surged nearly 350 percent from the previous year on a spike in sales of PC memory chips.