A new study finds that cyclic bursts of a STAT3 inhibitor can replenish muscle stem cells and promote their differentiation into muscle fibers. The findings are an important step toward developing and maintaining new muscle to treat muscle diseases.
Researchers at Sanford-Burnham Medical Research Institute (Sanford-Burnham) have developed a novel technique to promote tissue repair in damaged muscles. The technique also creates a sustainable pool of muscle stem cells needed to support multiple rounds of muscle repair.
The study, published September 7 in Nature Medicine, provides promise for a new therapeutic approach to treating the millions of people suffering from muscle diseases, including those with muscular dystrophies and muscle wasting associated with cancer and aging.
There are two important processes that need to happen to maintain skeletal-muscle health. First, when muscle is damaged by injury or degenerative disease such as muscular dystrophy, muscle stem cells—or satellite cells—need to differentiate into mature muscle cells to repair injured muscles.
Second, the pool of satellite cells needs to be replenished so there is a supply to repair muscle in case of future injuries. In the case of muscular dystrophy, the chronic cycles of muscle regeneration and degeneration that involve satellite-cell activation exhaust the muscle stem-cell pool to the point of no return.
"Our study found that by introducing an inhibitor of the STAT3 protein in repeated cycles, we could alternately replenish the pool of satellite cells and promote their differentiation into muscle fibers," said Alessandra Sacco, Ph.D., assistant professor in the Development, Aging, and Regeneration Program at Sanford-Burnham. "Our results are important because the process works in mice and in human muscle cells."
"Our next step is to see how long we can extend the cycling pattern, and test some of the STAT3 inhibitors currently in clinical trials for other indications such as cancer, as this could accelerate testing in humans," added Sacco.
"These findings are very encouraging. Currently, there is no cure to stop or reverse any form of muscle-wasting disorders—only medication and therapy that can slow the process," said Vittorio Sartorelli, M.D., chief of the Laboratory of Muscle Stem Cells and Gene Regulation and deputy scientific director at the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). "A treatment approach consisting of cyclic bursts of STAT3 inhibitors could potentially restore muscle mass and function in patients, and this would be a very significant breakthrough."
Revealing the mechanism of STAT3
STAT3 (signal transducer and activator of transcription 3) is a protein that activates the transcription of genes in response to IL-6, a signaling protein released by cells in response to injury and inflammation. Prior to the study, scientists knew that STAT3 played a complex role in skeletal muscle, promoting tissue repair in some instances and hindering it in others. But the precise mechanism of how STAT3 worked was a mystery.
The research team first used normally aged mice and mice models of a form of muscular dystrophy that resembles the human disease to see what would happen if they were given a drug to inhibit STAT3. They found that the inhibitor initially promoted satellite-cell replication, followed by differentiation of the satellite cells into muscle fibers. When they injected the STAT3 inhibitor every seven days for 28 days, they found an overall improvement in skeletal-muscle repair, and an increase in the size of muscle fibers.
"We were pleased to find that we achieved similar results when we performed the experiments in human muscle cells," said Sacco. "We have discovered that by timing the inhibition of STAT3—like an "on/off" light switch—we can transiently expand the satellite-cell population followed by their differentiation into mature muscle cells."
About Sanford-Burnham Medical Research Institute
Sanford-Burnham Medical Research Institute is dedicated to discovering the fundamental molecular causes of disease and devising the innovative therapies of tomorrow. Sanford-Burnham takes a collaborative approach to medical research with major programs in cancer, neurodegeneration and stem cells, diabetes, and infectious, inflammatory, and childhood diseases. The Institute is recognized for its National Cancer Institute-designated Cancer Center, its NIH-designated Neuroscience Center Cores, and expertise in drug discovery technologies. Sanford-Burnham is a nonprofit, independent institute that employs more than 1,000 scientists and staff in San Diego (La Jolla), Calif., and Orlando (Lake Nona), Fla. For more information, visit us at sanfordburnham.org.
Sanford-Burnham can also be found on Facebook at facebook.com/sanfordburnham and on Twitter @sanfordburnham.
Deborah Robison | Eurek Alert!
Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care
Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses