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 A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>