UCLA scientists have developed a gene editing strategy to alter the genetic defect in muscle cells using stem cells derived from patients with Duchenne muscular dystrophy (DMD), a deadly disorder that affects children. Patient cells, with a variety of different mutations, were repaired and demonstrated restored function after the scientists used a single CRISPR/Cas9 gene editing strategy applicable to the majority of DMD patients. This proof-of-concept study appears in Cell Stem Cell.

Laboratories around the world are working to find a treatment for DMD, which affects approximately 1 in 5,000 boys. The disease causes progressive muscle wasting and death in the twenties. Other labs have used CRISPR to repair mutations that apply to smaller numbers of patients and in cell types that aren't necessarily clinically relevant. In this study, the researchers created "corrected" human induced pluripotent stem cell lines that could directly restore the muscle tissue that is affected by DMD.

"This work demonstrates the feasibility of using a single gene editing platform to edit the mutant DMD gene for a majority of DMD patients," says co-senior author April Pyle, associate professor of microbiology, immunology, and molecular genetics and member of the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA.

"Because the platform can work on a variety of different mutations, it sets the stage for direct translation to patients with DMD, either through transplantation of these stem cells or delivery of the platform by other means," says Melissa Spencer, professor of neurology, co-director of the Center for Duchenne Muscular Dystrophy at UCLA, member of the Broad Stem Cell Research Center and co-senior author.

The team, led by first author graduate student Courtney Young, next plan to develop strategies to deliver the CRISPR platform in living animals using stem cells or direct delivery.