Featured Research

from universities, journals, and other organizations

Protein Causes Muscle Wasting Syndrome In Mice; Possible Clue To Treatments For Muscular Dystrophy, Other Conditions

Date:
May 27, 2002
Source:
Johns Hopkins Medical Institutions
Summary:
The Johns Hopkins researchers who first identified myostatin as a key restrictor of muscle growth in animals now report that excessive amounts of the protein in mice cause rapid and dramatic loss of both muscle and fat, without affecting appetite.

The Johns Hopkins researchers who first identified myostatin as a key restrictor of muscle growth in animals now report that excessive amounts of the protein in mice cause rapid and dramatic loss of both muscle and fat, without affecting appetite.

The results, obtained by implanting cells engineered to make extra myostatin into adult mice, support the idea of targeting myostatin to find potential new treatments for muscle-wasting diseases like muscular dystrophy, the team from Johns Hopkins and pharmaceutical company Wyeth report in the May 24 issue of Science.

"We now know that myostatin can affect muscle growth and maintenance in adult animals and that it acts throughout the body," says Se-Jin Lee, M.D., Ph.D., professor of molecular biology and genetics in the School of Medicine's Institute for Basic Biomedical Sciences. "These are key pieces of information, because agents interfering with myostatin could only help if the protein normally acts postnatally."

The situation observed in mice is similar to a common and largely untreatable complication of certain cancers, AIDS and other diseases in humans -- extreme loss of both muscle and fat, even while food consumption is normal. However, the researchers caution that it's still unknown whether myostatin is involved in the human wasting syndrome, called cachexia (ka-KEX-ee-a).

"We don't know whether myostatin is a key mediator in human wasting syndromes, but our findings raise the possibility that blocking myostatin activity may have beneficial effects in patients with cachexia," says Teresa Zimmers, Ph.D., who carried out the studies as a graduate student at Hopkins. "At the very least the finding will help clarify aspects of muscle wasting in general."

Previous studies had proved that myostatin normally limits muscle growth; mice without a working myostatin gene develop more muscle than normal mice, making them so-called "mighty mice." Until now the researchers weren't sure if myostatin would affect adult animals as well.

To find out, the researchers engineered cellular myostatin factories -- hamster cells altered to make and release lots of the protein. The scientists also created a line of these cells that make a naturally occurring myostatin blocker, a protein called follistatin.

After implanting the cells into mice, the scientists saw that those with myostatin-producing cells had dramatic weight loss, even though they ate the same as other mice. Mice with follistatin-producing cells to counteract their myostatin-producing ones lost significantly less weight, the researchers report.

"A few other proteins have been shown to cause muscle wasting in mice, but they also reduced the animals' appetites," says Zimmers. "That myostatin causes wasting without appetite changes makes its wasting syndrome much more similar, at least on the surface, to that in people."

But despite the similarities, the researchers don't know yet whether myostatin is actually important in human muscle wasting diseases or conditions. "Based on what we know about myostatin, we're hopeful that it's involved, but we have no direct evidence of that yet," says Lee.

"Regardless, treating cachexia still would not treat the underlying condition -- cancer, AIDS or what-have-you," notes Lee. "But because cachexia is the direct cause of death in many cases, we hope that relieving it could improve outcomes and treatment options for patients."

When animals don't eat, fat is lost at a predictable rate depending on the body's burning of calories. However, in cachexia, muscle and fat are both lost at an inexplicably fast rate even when food intake is normal. For people, the condition is defined by a loss of 10 percent of body weight in six months or 5 percent in 30 days, says Lee.

Other authors on the paper are Leonidas Koniaris, Aurora Esquela and Alexandra McPherron of the Johns Hopkins School of Medicine; and Monique Davies, Paul Haynes, Kathy Tomkinson and Neil Wolfman of Wyeth Pharmaceuticals, Cambridge, Mass. Zimmers and Koniaris are now at the University of Rochester School of Medicine and Dentistry. Haynes is now at the Torrey Mesa Research Institute, San Diego.

The research was supported by grants from the National Institutes of Health and funds from American Home Products (AHP). Myostatin was licensed by The Johns Hopkins University to MetaMorphix (MMI) and sublicensed to AHP. Lee and McPherron are entitled to a share of sales royalty received by the University from sales of this factor. The University, Lee, McPherron and Esquela also own MMI stock, which is subject to certain restrictions under University policy. Lee is a paid consultant to MMI. The terms of these arrangements are being managed by the University in accordance with its conflict of interest policies.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "Protein Causes Muscle Wasting Syndrome In Mice; Possible Clue To Treatments For Muscular Dystrophy, Other Conditions." ScienceDaily. ScienceDaily, 27 May 2002. <www.sciencedaily.com/releases/2002/05/020527081926.htm>.
Johns Hopkins Medical Institutions. (2002, May 27). Protein Causes Muscle Wasting Syndrome In Mice; Possible Clue To Treatments For Muscular Dystrophy, Other Conditions. ScienceDaily. Retrieved September 3, 2014 from www.sciencedaily.com/releases/2002/05/020527081926.htm
Johns Hopkins Medical Institutions. "Protein Causes Muscle Wasting Syndrome In Mice; Possible Clue To Treatments For Muscular Dystrophy, Other Conditions." ScienceDaily. www.sciencedaily.com/releases/2002/05/020527081926.htm (accessed September 3, 2014).

Share This



More Plants & Animals News

Wednesday, September 3, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Snack Attack: Study Says Action Movies Make You Snack More

Snack Attack: Study Says Action Movies Make You Snack More

Newsy (Sep. 2, 2014) You're more likely to gain weight while watching action flicks than you are watching other types of programming, says a new study published in JAMA. Video provided by Newsy
Powered by NewsLook.com
Get A Mortgage, Receive A Cat — Only In Russia

Get A Mortgage, Receive A Cat — Only In Russia

Newsy (Sep. 2, 2014) The incentive is in keeping with a Russian superstition that it's good luck for a cat to be the first to cross the threshold of a new home. Video provided by Newsy
Powered by NewsLook.com
U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Sharks Off the Menu and on the Tourist Trail in Palau

Sharks Off the Menu and on the Tourist Trail in Palau

AFP (Sep. 2, 2014) Tourists in Palau clamour to dive with sharks thanks to a pioneering conservation initiative -- as the island nation plans to completely ban commercial fishing in its vast ocean territory. 01:15 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins