Mutant protein in muscle linked to neuromuscular disorder

April 16, 2014
Mutant protein in muscle linked to neuromuscular disorder
This is a graphic of the SBMA mouse model. Credit: UC San Diego School of Medicine

Sometimes known as Kennedy's disease, spinal and bulbar muscular atrophy (SBMA) is a rare inherited neuromuscular disorder characterized by slowly progressive muscle weakness and atrophy. Researchers have long considered it to be essentially an affliction of primary motor neurons – the cells in the spinal cord and brainstem that control muscle movement.

But in a new study published in the April 16, 2014 online issue of Neuron, a team of scientists at the University of California, San Diego School of Medicine say novel mouse studies indicate that mutant protein levels in cells, not , are fundamentally involved in SBMA, suggesting an alternative and promising new avenue of treatment for a condition that is currently incurable.

SBMA is an X-linked recessive disease that affects only males, though females carrying the defective gene have a 50:50 chance of passing it along to a son. It belongs to a group of diseases, such as Huntington's disease, in which a C-A-G DNA sequence is repeated too many times, resulting in a protein with too many glutamines (an amino acid), causing the diseased protein to misfold and produce harmful consequences for affected cells. Thus far, human clinical trials of treatments to protect against these repeat toxicities have failed.

In the new paper, a team led by principal investigator Albert La Spada, MD, PhD, professor of pediatrics, cellular and molecular medicine, and neurosciences, and the associate director of the Institute for Genomic Medicine at UC San Diego, propose a different therapeutic target. After creating a new mouse model of SBMA, they discovered that skeletal muscle was the site of mutant protein toxicity and that measures which mitigated the protein's influence in muscle suppressed symptoms of SBMA in treated mice, such as weight loss and progressive weakness, and increased survival.

In a related paper, published in the April 16, 2014 online issue of Cell Reports, La Spada and colleagues describe a potential treatment for SBMA. Currently, there is none.

The scientists developed antisense oligonucleotides – sequences of synthesized genetic material – that suppressed androgen receptor (AR) gene expression in peripheral tissues, but not in the central nervous system. Mutations in the AR gene are the cause of SBMA, a discovery that La Spada made more than 20 years ago while a MD-PhD student.

La Spada said that antisense therapy helped mice modeling SBMA to recover lost muscle weight and strength and extended survival.

"The main points of these papers is that we have identified both a genetic cure and a drug cure for SBMA – at least in mice. The goal now is to further develop and refine these ideas so that we can ultimately test them in people," La Spada said.

Explore further: Neurological disorder impacts brain cells differently

Related Stories

Neurological disorder impacts brain cells differently

November 9, 2011
In a paper published in the Nov. 9 issue of the Journal of Neuroscience, researchers at the University of California, San Diego School of Medicine and University of Washington describe in deeper detail the pathology of a ...

Two proteins offer a 'clearer' way to treat Huntington's disease

July 11, 2012
In a paper published in the July 11 online issue of Science Translational Medicine, researchers at the University of California, San Diego School of Medicine have identified two key regulatory proteins critical to clearing ...

Having Huntington's disease or other 'polyQ' diseases protects against cancer, suggesting common genetic mechanism

April 11, 2012
Having Huntington's disease or other diseases known as polyglutamine (polyQ) diseases reduces a person's risk of getting cancer, suggesting a common genetic mechanism, concludes an Article published Online First by The Lancet ...

Recommended for you

Molecular hitchhiker on human protein signals tumors to self-destruct

July 24, 2017
Powerful molecules can hitch rides on a plentiful human protein and signal tumors to self-destruct, a team of Vanderbilt University engineers found.

Researchers develop new method to generate human antibodies

July 24, 2017
An international team of scientists has developed a method to rapidly produce specific human antibodies in the laboratory. The technique, which will be described in a paper to be published July 24 in The Journal of Experimental ...

New vaccine production could improve flu shot accuracy

July 24, 2017
A new way of producing the seasonal flu vaccine could speed up the process and provide better protection against infection.

A sodium surprise: Engineers find unexpected result during cardiac research

July 20, 2017
Irregular heartbeat—or arrhythmia—can have sudden and often fatal consequences. A biomedical engineering team at Washington University in St. Louis examining molecular behavior in cardiac tissue recently made a surprising ...

Want to win at sports? Take a cue from these mighty mice

July 20, 2017
As student athletes hit training fields this summer to gain the competitive edge, a new study shows how the experiences of a tiny mouse can put them on the path to winning.

'Smart' robot technology could give stroke rehab a boost

July 19, 2017
Scientists say they have developed a "smart" robotic harness that might make it easier for people to learn to walk again after a stroke or spinal cord injury.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.