Nav: Home

Protein found to bolster growth of damaged muscle tissue

July 19, 2016

Johns Hopkins University biologists have found that a protein that plays a key role in the lives of stem cells can bolster the growth of damaged muscle tissue, a step that could potentially contribute to treatments for muscle degeneration caused by old age and diseases such as muscular dystrophy.

The results, published online by the journal Nature Medicine, show that a particular type of protein called integrin is present on the stem cell surface and used by stem cells to interact with, or "sense" their surroundings. How stem cells sense their surroundings, also known as the stem cell "niche," affects how they live and last for regeneration. The presence of the protein β1-integrin was shown to help promote the transformation of those undifferentiated stem cells into muscle after the tissue has degraded, and improve regenerated muscle fiber growth as much as 50 percent.

While the presence of β1-integrin in adult stem cells is apparent, "its role in these cells has not been examined," especially its influence on the biochemical signals promoting stem cell growth, wrote the three authors, Chen-Ming Fan, an adjunct biology professor; Michelle Rozo, who completed her doctorate in biology at Johns Hopkins this year; and doctoral student Liangji Li.

The experiment shows that β1-integrin - one of 28 types of integrin - maintains a link between the stem cell and its environment, and interacts biochemically with a growth factor called fibroblast growth factor [FGF] to promote stem cell growth and restoration after muscle tissue injury. Aged stem cells do not respond to FGF, and the results also show that β1-integrin restores aged stem cell's ability to respond to FGF to grow and improve muscle regeneration.

By tracking an array of proteins inside the stem cells, the researchers tested the effects of removing β1-integrin from the stem cell. This is based on the understanding that the activities of stem cells - undifferentiated cells that can become specialized - are dependent on their environment and supported by the proteins found there.

"If we take out β1-integrin, all these other (proteins) are gone," said Fan, the study's senior author and a staff member at the Carnegie Institution for Science in Washington and Baltimore.

Why that is the case is not clear, but the experiment showed that without β1-integrin, stem cells could not sustain growth after muscle tissue injury.

By examining β1-integrin molecules and the array of proteins that they used to track stem cell activity in aged muscles, the authors found that all of these proteins looked like they had been removed from aged stem cells. They injected an antibody to boost β1-integrin function into aged muscles to test whether this treatment would enhance muscle regeneration. Measurements of muscle fiber growth with and without boosting the function of β1-integrin showed that the protein led to as much as 50-percent more regeneration in cases of injury in aged mice.

When the same β1-integrin function-boosting strategy was applied to mice with muscular dystrophy, the muscle was able to increase strength by about 35 percent.

Fan said the team's research will next try to determine what is happening inside the stem cells as they react with their immediate environment, as a step to understanding more about the interaction of the two. That, in turn, could help refine the application of integrin as a therapy for muscular dystrophy and other diseases, and for age-related muscle degeneration.

"We provide here a proof-of-principle study that may be broadly applicable to muscle diseases that involve SC (stem cell) niche dysfunction," the authors wrote. "But further refinement is needed for this method to become a viable treatment."
-end-
Funding for this work was provided by the Carnegie Institution for Science and the National Institutes of Health (AR060042 and HD075345).

Johns Hopkins University

Related Stem Cells Articles:

First events in stem cells becoming specialized cells needed for organ development
Cell biologists at the University of Toronto shed light on the very first step stem cells go through to turn into the specialized cells that make up organs.
Surprising research result: All immature cells can develop into stem cells
New sensational study conducted at the University of Copenhagen disproves traditional knowledge of stem cell development.
The development of brain stem cells into new nerve cells and why this can lead to cancer
Stem cells are true Jacks-of-all-trades of our bodies, as they can turn into the many different cell types of all organs.
Healthy blood stem cells have as many DNA mutations as leukemic cells
Researchers from the Princess Máxima Center for Pediatric Oncology have shown that the number of mutations in healthy and leukemic blood stem cells does not differ.
New method grows brain cells from stem cells quickly and efficiently
Researchers at Lund University in Sweden have developed a faster method to generate functional brain cells, called astrocytes, from embryonic stem cells.
NUS researchers confine mature cells to turn them into stem cells
Recent research led by Professor G.V. Shivashankar of the Mechanobiology Institute at the National University of Singapore and the FIRC Institute of Molecular Oncology in Italy, has revealed that mature cells can be reprogrammed into re-deployable stem cells without direct genetic modification -- by confining them to a defined geometric space for an extended period of time.
Researchers develop a new method for turning skin cells into pluripotent stem cells
Researchers at the University of Helsinki, Finland, and Karolinska Institutet, Sweden, have for the first time succeeded in converting human skin cells into pluripotent stem cells by activating the cell's own genes.
In mice, stem cells seem to work in fighting obesity! What about stem cells in humans?
This release aims to summarize the available literature in regard to the effect of Mesenchymal Stem Cells transplantation on obesity and related comorbidities from the animal model.
TSRI researchers identify gene responsible for mesenchymal stem cells' stem-ness'
Researchers at The Scripps Research Institute recently published a study in the journal Cell Death and Differentiation identifying factors crucial to mesenchymal stem cell differentiation, providing insight into how these cells should be studied for clinical purposes.
Stem cells in intestinal lining may shed light on behavior of cancer cells
The lining of the intestines -- the epithelium -- does more than absorb nutrients from your lunch.
More Stem Cells News and Stem Cells Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.