Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mice stressed in simulated weightlessness show organ atrophy

04.09.2007
Rutgers researchers track osteopontin-dependent changes in thymus and spleen

A ground-based, experimental model used to simulate astronaut weightlessness in space has provided Rutgers scientists an opportunity to study the effects of stress on immune organs.

Earlier collaborative research with Japanese scientists employing this model implicated the protein osteopontin (OPN) in bone mineral loss associated with simulated weightlessness in mice. This research was made possible by the creation at Rutgers of a mouse unable to make OPN (a “knock-out” mouse). Studies with this Rutgers mouse have demonstrated that OPN likely plays a role in a variety of human problems including cancer metastasis, multiple sclerosis and other autoimmune diseases, osteoporosis and certain inflammatory responses.

The new study, which also simulated weightlessness, demonstrated that OPN is required for the atrophy of immune organs brought on by the stress resulting from hindlimb unloading – a technique employed to simulate weightless conditions by lifting the animal’s body weight off its hind legs. Results are presented Sept. 3 online in the Proceedings of the National Academy of Sciences (PNAS) and in the Sept. 11 print issue.

... more about:
»Condition »OPN »Thymus »atrophy »bone loss »simulated

“The bone loss seen in astronauts or bedridden patients is not a stress issue,” explained David Denhardt, a professor in the Department of Cell Biology and Neuroscience at Rutgers, The State University of New Jersey. “They are experiencing a loss of weight bearing on the bones, and the loss of bone mineral is a direct result of this load reduction.”

The presence of OPN, a feature common to both the bone loss and the organ atrophy, is produced by two different causes – weightlessness and stress – coincidentally related to the same laboratory conditions.

OPN is the continuing focus of Denhardt’s research interests. His long-term goal is to develop an OPN antibody – a monoclonal or target-specific antibody – that will inhibit OPN function in lab mice, and ultimately, in humans. This antibody could prove useful in treating the many destructive diseases associated with OPN.

Denhardt’s graduate student Kathryn Wang, a co-author on the PNAS paper, had previously conducted experiments in which the mouse was positioned in such a way as to produce hind limb unloading. This simulated weightless condition produced OPN-dependent bone loss in the hind limbs and provided a potential testing ground for possible OPN antibodies. The specialized equipment for that experiment was supplied by another co-author on the paper, Yufang Shi, a professor in the Department of Molecular Genetics, Microbiology and Immunology at Robert Wood Johnson Medical School–University of Medicine and Dentistry of New Jersey.

Shi, an authority on stress, suggested that along with the bone loss studies, the Rutgers researchers should look at the spleen and thymus – the organs responsible for most of the animal’s immune cells. If stress affects the spleen and thymus so that they atrophy, the immune system becomes impaired. People under severe stress often get sick.

The Rutgers scientists took their colleague’s advice and compared the OPN-deficient knock-out mice to normal mice, with some dramatic results.

“To our astonishment and surprise, the OPN-deficient animals responded differently to the stress than the normal controls,” Denhardt said. “We had no basis to expect this, but the spleen and thymus of the OPN-deficient animals remained normal whereas there was atrophy of the spleen and thymus in the normal controls. This was a novel and totally unexpected result for which we have no explanation at this time. The next phase of our research will ask what exactly is going on.”

The stressed normal mice also displayed elevated levels of corticosterone – a hormone known to induce apoptosis (programmed cell death), a process evident in the spleen and thymus of these mice and a possible mechanism underlying the atrophy.

Denhardt said that their results indicate that OPN needs to be present for these stress related symptoms to occur, pointing to a whole new physiological realm in which the culprit osteopontin is causing problems.

Joseph Blumberg | EurekAlert!
Further information:
http://www.rutgers.edu

Further reports about: Condition OPN Thymus atrophy bone loss simulated

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>