Gene-editing technique heals mice with muscular dystrophy

DMD mice treated with the technique produced dystrophin protein and progressively showed improved structure and function of skeletal muscle and heart.

That gene editing was done in the fertilised egg of the mouse, making an inheritable change to the mouse’s genome.

Because the disease is devastating and incurable, and common for a hereditary illness, it has always been a target for gene therapy, though without success.

The studies focus on the team of researchers attempting and succeeding in curing an adult mouse suffering from the infamous Duchenne muscular dystrophy, efforts rewarded due to their use of the CRISPR technology – clustered regularly interspaced short palindromic repeats. Since germ line editing is not feasible in humans, strategies would need to be developed to deliver gene-editing components to postnatal tissues. It is also the most common and severe form of muscular dystrophy among boys, UPI reports.

For past three decades, the genetic reason of the disease is known but no effective treatment is available for the same. If the technique is advanced then the technique could lead to one of the successful genome-editing based treatments for the disease.

For the study, researchers used the adeno-associated virus 9 to send gene-editing components to mice cells. A team of researchers conducted the research on mice with a defective gene that leads to Duchenne muscular dystrophy. The researchers that achieved this impressive feat did so using the CRISPR genetic editing machine.

Professor Rhonda Bassel-Duby, Co-Principal Investigator of a genomic editing project with Dr Olson, said: “This study represents a very important translational application of genome editing of DMD mutations in young mice”.

CRISPR-Cas9 is a simple, fast and affordable gene editing system discovered three years ago, which is now being used by laboratories all over the world.

“Recent discussion about using CRISPR to correct genetic mutations in human embryos has rightfully generated considerable concern regarding the ethical implications of such an approach”, said Gersbach. University of Texas researchers were able to correct the gene mutation that causes the disease in mice.

And a virus was used to deliver DNA alterations into the cells of mice.

Now, the research team is working to apply this gene-editing technique to cells from DMD patients and in larger preclinical animal models.

This is what happens in a milder disease known as Becker muscular dystrophy, in which mutations cause instructions from a few exons to be skipped during the protein-making process.

“There is still a significant amount of work to do to translate this to a human therapy and demonstrate safety”, said Charles Gersbach, associate professor of biomedical engineering at Duke University in a statement. The virus infected muscle cells throughout the mouse’s body, snipping out the exon from the dystrophin gene.

For now, the CRISPR has only shown to be effective against DMD, which is a condition in which the person experiences a lot of weakness and a loss in muscle function. Moreover, AAV is in use in many late-stage clinical trials in the United States and has already been approved for use in one gene therapy drug in the European Union.