Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers alleviate symptoms of Rett syndrome in mice

02.02.2006


Rett syndrome is a debilitating neurological disorder occurring primarily in girls. While some existing therapies might ease particular symptoms of the condition, there is no current way to address the syndrome at a molecular level. Now, researchers at Whitehead Institute for Biomedical Research, in collaboration with scientists at Brandeis University, have dramatically reduced certain manifestations of Rett Syndrome in mice, marking a clear path in which to explore possible therapies for people.



"This is the first time we’ve successfully reduced the awful symptoms of Rett syndrome using transgenic techniques," says Whitehead Member Rudolf Jaenisch, senior author of the paper that will be published February 2 in the journal Neuron. "Once we understand the molecular mechanisms of the disease we may be able to design rational strategies that may eventually be useful for the improving the condition in people."

Rett syndrome, whose incidence is roughly 1 in 15,000, is caused by a defective gene on the X chromosome. Most boys with Rett syndrome die before birth. Girls with Rett develop normally until about six to eighteen months, when things begin to go terribly wrong. Their health deteriorates, and they begin to show symptoms such as loss of speech, loss of voluntary motor control, constant hand wringing and seizures.


In March 2001, researchers in the Jaenisch lab published a paper in Nature Genetics describing how they had created the first mouse with Rett syndrome by disabling a gene called MeCP2. Normally, MeCP2 regulates the activities of other genes, particularly those in the brain. When it is shut off completely, the mice become lethargic and a major class of cortical neurons became far less active--classic symptoms of Rett.

In the fall of 2003, Jaenisch and researchers at Children’s Hospital Boston reported in the journal Science that MeCP2 interacted with a neuronal gene called Bdnf, a gene that’s highly active in infants age 6 to 18 months--the same age at which Rett symptoms first appear. But since this study was conducted using explanted neurons in a laboratory dish, researchers still had many unanswered questions about the role of Bdnf in Rett disease progression in mice.

Qiang Chang, a postdoctoral scientist in the Jaenisch lab, began to explore this issue by studying the population of the MeCP2 knock-out mice that Jaenisch had reported on in 2001. His first finding, gleaned through analyzing brain tissue, was not altogether unexpected: Mice without MeCP2 also showed low expression levels of the BDNF protein. In fact, Chang discovered that when he knocked out Bdnf altogether in normal mice, symptoms similar to those observed in the Rett mice occurred. But to discover whether or not these finding might have therapeutic relevance, Chang needed to engage in some complex genetic tinkering.

Chang inserted an additional Bdnf gene into the early embryos of the MeCP2 knock-out mice. He designed the gene so that it would be free of all normal regulatory mechanisms, in effect ensuring that it remains in a state of constant activity. In other words, while MeCP2 was permanently shut off, the new Bdnf was permanently switched on, and at maximum capacity.

This time, the findings were striking.

With BDNF hyper-expressed, Chang witnessed a drastic reduction in certain Rett symptoms. The mice were far less lethargic, and activity in the cortical neurons increased. These mice also had slightly larger brains, a longer lifespan and later onset of disease than the other Rett mice.

"The next step," says Chang, "is to figure out exactly why this is happening. Exactly how much BDNF expression in the mouse brain do you need to achieve these results, and where does it occur?"

"Knowing more about the process and about the precise areas of the brain that are affected will give us options for exploring future therapies," explains Jaenisch, who is also a professor of biology at MIT.

"We’re encouraged by these results," says Monica Coenraads, co-founder and director of research for Rett Syndrome Research Foundation, who helped support this work. "Should this prove to be therapeutically relevant, we look forward to participating in the transition from lab to clinic."

David Cameron | EurekAlert!
Further information:
http://www.wi.mit.edu

More articles from Life Sciences:

nachricht World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>