Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study links autistic behaviors to enzyme

24.07.2014

UC Riverside-led mouse study shows that deleting the enzyme favorably impacts behaviors associated with Fragile X syndrome

Fragile X syndrome (FXS) is a genetic disorder that causes obsessive-compulsive and repetitive behaviors, and other behaviors on the autistic spectrum, as well as cognitive deficits. It is the most common inherited cause of mental impairment and the most common cause of autism.


Iryna Ethell is a professor of biomedical sciences in the UC Riverside School of Medicine.

Credit: L. Duka.

Now biomedical scientists at the University of California, Riverside have published a study that sheds light on the cause of autistic behaviors in FXS. Appearing online today (July 23) in the Journal of Neuroscience, and highlighted also on the cover in this week's print issue of the journal, the study describes how MMP-9, an enzyme, plays a critical role in the development of autistic behaviors and synapse irregularities, with potential implications for other autistic spectrum disorders.

MMP-9 is produced by brain cells. Inactive, it is secreted into the spaces between cells of the brain, where it awaits activation. Normal brains have quite a bit of inactive MMP-9, and the activation of small amounts has significant effects on the connections between neurons, called synapses. Too much MMP-9 activity causes synapses in the brain to become unstable, leading to functional deficits.

"Our study targets MMP-9 as a potential therapeutic target in Fragile X and shows that genetic deletion of MMP-9 favorably impacts key aspects of FXS-associated anatomical alterations and behaviors in a mouse model of Fragile X," said Iryna Ethell, a professor of biomedical sciences in the UC Riverside School of Medicine, who co-led the study. "We found that too much MMP-9 activity causes synapses to become unstable, which leads to functional deficits that depend on where in the brain that occurs."

Ethell explained that mutations in FMR1, a gene, have been known for more than a decade to cause FXS, but until now it has been unclear how these mutations cause unstable synapses and characteristic physical features of this disorder. The new findings expand on earlier work by the research group that showed that an MMP-9 inhibitor, minocycline, can reduce behavioral aspects of FXS, which then led to its use to treat FXS.

To further establish a causative role for MMP-9 in the development of FXS-associated features, including autistic behaviors, the authors generated mice that were missing both FMR1 and MMP-9. They found that while mice with a single FMR1 mutation showed autistic behaviors and macroorchidism (abnormally large testes), mice that also lacked MMP-9 showed no autistic behaviors.

"Our work points directly to MMP-9 over-activation as a cause for synaptic irregularities in FXS, with potential implications for other autistic spectrum disorders and perhaps Alzheimer's disease," said Doug Ethell, the head of Molecular Neurobiology at the Western University of Health Sciences, Pomona, Calif., and a coauthor on the study.

The research paper represents many years of bench work and effort by a dedicated team led by the Ethells. The work was primarily done in mice, but human tissue samples were also analyzed, with findings found to be consistent. Specifically, the work involved assessing behaviors, biochemistry, activity and anatomy of synaptic connections in the brain of a mouse model of FXS, as well as the creation of a new mouse line that lacked both the FXS gene and MMP-9.

FXS affects both males and females, with females often having milder symptoms than males. It is estimated that about 1 in 5,000 males are born with the disorder.

The Ethells were joined in the study by UCR's Harpreet Sidhu (first author of the research paper), Lorraine E. Dansie, and Peter Hickmott. Sidhu and Dansie are neuroscience graduate students; Hickmott is an associate professor of psychology.

Next, the researchers plan to understand how MMP-9 regulates synapse stability inside the neurons. They also plan to find drugs that specifically target MMP-9 without side effects such as new tetracycline derivatives that are potent inhibitors of MMP-9 but lack antibiotic properties.

"Although minocycline was successfully used in clinical trial in FXS, it has some side effects associated with its antibiotic properties, such gastrointestinal irritation," Iryna Ethell said. "We, therefore, plan to test new non-antibiotic minocycline derivatives. These compounds lack antibiotic activity but still act as non-competitive inhibitors of MMP-9 similar to minocycline."

###

The research was funded by grants from the FRAXA Research Foundation, the National Institutes of Health and the California Institute for Regenerative Medicine.

The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion. A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.

Iqbal Pittalwala | Eurek Alert!

Further reports about: FMR1 FXS activity antibiotic autistic deficits disorder enzyme spectrum synapses

More articles from Studies and Analyses:

nachricht The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>