CRISPR/Cas9

The CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats) method for genome editing is a powerful new technology with many applications in biomedical research, including the potential to treat human genetic diseases, such as muscular dystrophy. CRISPR/Cas9 allows researchers to edit parts of the genome by removing, adding, or changing sections of the DNA sequence.

What is muscular dystrophy?

Muscular dystrophy refers to a group of genetic diseases characterized by muscle weakness and atrophy. There are many types of muscular dystrophy, and most are caused by mutations in genes that provide instructions for cells to make structural proteins that are important in muscle development and function. There is currently no cure for muscular dystrophy, but there are treatments available to manage symptoms. There also are new experimental treatments that are being explored to slow or halt the progression of muscular dystrophy. 

What is CRISPR/Cas9?

The CRISPR/Cas9 method is based on bacteria’s natural system to protect itself from viral infections (similar to an immune system). When bacteria detect the presence of foreign (viral) DNA, the CRISPR proteins capture a piece of the virus’ DNA and insert that piece into the bacteria’s own genome. The bacteria then uses the “immunizing” viral DNA piece to produce “antibodies” that recognize and defend against future viral attacks.
The bacterial “antibodies” are composed of two types of short RNA, one of which contains a sequence that matches that of the invading virus. These two RNAs form a complex with a protein called Cas9. Cas9 is a nuclease (a type of enzyme that can cut DNA). When the matching sequence (called a “guide” RNA) finds its target within the viral genome, the Cas9 cuts the viral DNA, disabling the virus and preventing it from replicating.

How can CRISPR/Cas9 be used to treat muscular dystrophy?

The CRISPR/Cas9 system can be used to modify or correct genetic mutations in patient cells. Researchers are working to find the best way to treat different types of muscular dystrophy (and other genetic diseases) with CRISPR/Cas9.

The first human clinical trials of CRISPR/Cas9 treatments are underway for diseases such as cancer or cystic fibrosis, in which patient cells are isolated, treated to correct the genetic mutation, and then injected back into the patient to fight the disease.

For muscular dystrophy, a viral delivery system could provide patient cells with the instructions to make the Cas9 protein, as well as the “guide” RNAs that target specific regions of DNA.

For example, mouse models of Duchenne muscular dystrophy (DMD) — which is caused by mutations in the gene that provides instructions for making dystrophin — have been treated with a CRISPR/Cas9 system that was able to restore the function of dystrophin protein in muscle cells.

Similar pre-clinical studies are being conducted to assess the potential of the CRISPR/Cas9 system in treating other types of muscular dystrophy.

 

Last updated: Aug. 28, 2019

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Muscular Dystrophy News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

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