Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers Find a Way to Delay Aging of Stem Cells

25.05.2012
Salk scientists say their findings may lead to strategies to treat age-related diseases and improve regenerative medicine
Stem cells are essential building blocks for all organisms, from plants to humans. They can divide and renew themselves throughout life, differentiating into the specialized tissues needed during development, as well as cells necessary to repair adult tissue.

Therefore, they can be considered immortal, in that they recreate themselves and regenerate tissues throughout a person's lifetime, but that doesn't mean they don't age. They do, gradually losing their ability to effectively maintain tissues and organs.

Now, researchers at the Salk Institute for Biological Studies have uncovered a series of biological events that implicate the stem cells' surroundings, known as their "niche," as the culprit in loss of stem cells due to aging. Their findings, published May 23rd in Nature, have implications for treatment of age-related diseases and for the effectiveness of regenerative medicine.

"The findings suggest, for example, that putting new or young stem cells into an old environment----that of an aged patient----might not lead to the best outcome in tissue regeneration," says the study's senior investigator, Leanne Jones, associate professor in Salk's Laboratory of Genetics.

Stem cells reside within a microenvironment of other cells-the niche-that is known to play a role in stem cell function. For example, after a tissue is injured, the niche signals to stem cells to form new tissue. It is believed that stem cells and their niche send signals to each other to help maintain their potency over a lifetime.

But while the loss of tissue and organ function during aging has been attributed to decreases in stem cell function, it has been unclear how this decline occurs. Jones' lab has been investigating a number of possible scenarios, such as whether the loss of tissue function is due to a decrease in the number of stem cells, to the inability of stem cells to respond to signals from their niche, or to reduced signaling from the niche.

To explore stem cell aging, Jones uses cells found in the testes of the male fruit fly, Drosophila melanogaster, which are remarkably similar to those found in humans.

The researchers show how signals from the niche that act to maintain the vitality of the flies' stem cells are lost over time, leading to a decline in the number of stem cells available to maintain the tissue. They also show that restoring those signals revitalizes the cells.

"Stem cell behavior is similar between flies and humans, so our findings have major implications for breakthroughs in using tissue stem cells to treat age-related tissue decline or regeneration after an injury," says one of the paper's first authors, Hila Toledano, a former Salk investigator who is now at the University of Haifa in Israel.

The Salk researchers discovered that as the stem cell niche ages, the cells produce a microRNA (a molecule that plays a negative role in the production of proteins from RNA) known as let-7. This microRNA is known to exist in a number of species, including humans, and helps time events that occur during development.

This increase in let-7 leads to a domino effect that flips a switch on aging by influencing a protein known as Imp, whose function is to protect another molecule, Upd, which is secreted from a key area of the niche.

In short, Upd promotes the signaling that keeps stem cells active and in contact with the niche so that they can self-renew. And as aging advances, increasing expression of let-7 ultimately leads to lower Upd levels, decreasing the number of active stem cells in the niche. What leads to accumulation of let-7 in the niche of aged flies still remains an open question.

The researchers also demonstrated they could reverse this age-related loss of stem cells by increasing expression of Imp. "We turned the aging switch off," says Jones.

This antidote to aging might be accomplished in a number of ways, such as by preventing let-7 from being elevated, blocking the destruction of Upd or increase the expression of Imp. "This research opens new avenues for drug development aimed at stimulating a patient's own stem cells to overcome the consequences of aging," says Toledano.

Jones says the study uncovered a mechanism by which a niche can lose its supportive function and demonstrates this can be reversed. "In patients, this could include co-transplantation of components of the niche itself, or rejuvenation of the niche using drug therapy to support the transplanted stem cells," says Jones.

Co-authors include Cecilia D'Alterio, from the Laboratory of Genetics at Salk, Benjamin Czech, from the Howard Hughes Medical Institute and Cold Spring Harbor Laboratory, and Erel Levine, from Harvard University.

The study was funded by G. Harold and Leila Y. Mathers Charitable Foundation, Ellison Medical Foundation, Emerald Foundation, American Federation for Aging Research and National Institutes of Health.
About the Salk Institute for Biological Studies:
The Salk Institute for Biological Studies is one of the world's preeminent basic research institutions, where internationally renowned faculty probe fundamental life science questions in a unique, collaborative, and creative environment. Focused both on discovery and on mentoring future generations of researchers, Salk scientists make groundbreaking contributions to our understanding of cancer, aging, Alzheimer's, diabetes and infectious diseases by studying neuroscience, genetics, cell and plant biology, and related disciplines.

Image: Courtesy of the Salk Institute for Biological Studies

These fluorescent microscope images of testes from young (left) and old(right) fruit flies show the effect of aging on the stem cell niche (top center). The hub cells (red) that function as part of the stem cells' supporting niche express more of a microRNA known as let-7 (green) in aged flies, which changes the signaling properties of hub cells, leading to fewer stem cells surrounding the hub that are available for tissue maintenance.

Faculty achievements have been recognized with numerous honors, including Nobel Prizes and memberships in the National Academy of Sciences. Founded in 1960 by polio vaccine pioneer Jonas Salk, M.D., the Institute is an independent nonprofit organization and architectural landmark.

Andy Hoang | Newswise Science News
Further information:
http://www.salk.edu

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A cavity leads to a strong interaction between light and matter

Researchers have succeeded in creating an efficient quantum-mechanical light-matter interface using a microscopic cavity. Within this cavity, a single photon is emitted and absorbed up to 10 times by an artificial atom. This opens up new prospects for quantum technology, report physicists at the University of Basel and Ruhr-University Bochum in the journal Nature.

Quantum physics describes photons as light particles. Achieving an interaction between a single photon and a single atom is a huge challenge due to the tiny...

Im Focus: Solving the mystery of quantum light in thin layers

A very special kind of light is emitted by tungsten diselenide layers. The reason for this has been unclear. Now an explanation has been found at TU Wien (Vienna)

It is an exotic phenomenon that nobody was able to explain for years: when energy is supplied to a thin layer of the material tungsten diselenide, it begins to...

Im Focus: An ultrafast glimpse of the photochemistry of the atmosphere

Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...

Im Focus: Shaping nanoparticles for improved quantum information technology

Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.

Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...

Im Focus: Novel Material for Shipbuilding

A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.

The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

 
Latest News

Kirigami inspires new method for wearable sensors

22.10.2019 | Materials Sciences

3D printing, bioinks create implantable blood vessels

22.10.2019 | Medical Engineering

Ionic channels in carbon electrodes for efficient electrochemical energy storage

22.10.2019 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>