Newly developed molecule may help neutralize gene that causes muscular dystrophy

From Health News:

A newly developed molecule has been shown to neutralize the genetic flaw that causes the most common type of the muscle-wasting disease, muscular dystrophy. The muscular dystrophies are a group of more than 30 different genetic diseases that are characterized by the progressive weakness and degeneration of the skeletal muscles that control our movement. Some forms of muscular dystrophy can be seen in infancy or childhood, while other may not appear until middle age or later.

The researchers injected mice with a compound that is found to neutralize the faulty gene activity, after which the mice regained use of muscles that were frozen by myotonic dystrophy. Dr. Charles Thornton, from the University of Rochester in New York and whose study appears in the journal Science, said, “We haven’t corrected the underlying gene abnormality. What we’ve done is made it behave in a more mannerly fashion.”

The research relies on a technology that is called antisense, which uses synthetic molecules to help block the activity of the specific genes. Several companies, which include Isis Pharmaceuticals, are developing drugs that are using this approach. Thornton stated that unlike many of the inherited diseases in which faulty genes make faulty or missing proteins, myotonic dystrophy makes a toxic form of the ribonucleic acid, also known as RNA, which carries the genetic instructions for making our proteins. Thornton also said that in myotonic dystrophy, however, the RNA is toxic to cells. “This RNA has proteins that get stuck on it,” he stated.

Myotonic muscular dystrophy, which affects approximately 40,000 people in the United States, is marked by the inability to relax muscles. Thornton said that the people who suffer from myotonic dystrophy have all of the ingredients for a healthy body. “It’s just that some proteins are in the wrong location,” he stated in an interview.

To fix that problem, Thornton’s research team used antisense to create bits of genetic material that lock onto the RNA that is faulty. Typically, the antisense drugs destroy the offending RNA, but Thornton’s lab designed a particular molecule to simply neutralize the RNA that is toxic. Thornton said that he didn’t want to destroy the RNA. He simply wanted to get something that would bind to the RNA, an release the proteins that were stuck together so they could do their job.

The researchers injected this particular compound into the muscle tissue in the mice that had myotonic dystrophy. The proteins that were stuck together were released and resumed their normal function, which allowed the muscles to relax properly. Thornton said that their study showed promise for a new treatment for humans, but the team is still looking for a better way of getting the treatment into the body than a direct injection into the affected muscles. They also said that there is a need to study whether muscles that have wasted away because of this disease can be restored to normal tone and size after the treatment.