Year 3
In this project, we developed a stem cell therapy approach to treat muscular dystrophy. The approach had three steps. 1. In the first step, we utilized stem cells that had been created from patient tissues. Since muscular dystrophy is a genetic disease, we first had to correct the mutation in the patient’s stem cells. The correction was done by using several gene editing techniques that have been developed in recent years. The correction was successful, resulting in patient stem cells that now carried the correct version of the gene that had been mutated. 2. In the next step, we grew the stem cells in a fashion in which they would differentiate into cells that resembled muscle stem cells. This differentiation was done by exposing the stem cells to several small molecules that brought about differentiation. The differentiated stem cells looked and acted like muscle stem cells in a culture dish. 3. The final step was to reintroduce the corrected and differentiated stem cells back into muscle, where they might carry out repair of degenerating muscle tissue. For this step, we used a mouse model of muscular dystrophy that had a similar disease to that of the human patients. The mice were made immune-deficient so they would not reject injected human cells. We developed a procedure to introduce the corrected and differentiated human stem cells into muscle by injecting the cells into the bloodstream, where they travelled to all the muscles in the mouse hind limb. By carrying out this procedure, we obtained engraftment of low numbers of donor cells in the mouse muscles. While the whole procedure worked at the proof of principle level, aspects of the procedure were time-consuming, expensive, complicated, and inefficient. We are now seeking ways to improve the procedure to make it faster, cheaper, and more effective.