Curing diseases with CRISPR
Most strategies for treating genetic diseases focus on managing signs and symptoms, not on altering the gene itself. But recently, Berkeley Engineering researchers have successfully used CRISPR-Cas9 technology — a gene editing tool developed by Jennifer Doudna, professor of molecular and cell biology and of chemistry at Berkeley, and Emmanuelle Charpentier — to advance innovative cures for several formidable diseases:
Amyotrophic lateral sclerosis (ALS)
In the United States each year, about 6,000 people are diagnosed with amyotrophic lateral sclerosis (ALS) — also called Lou Gehrig’s disease — with a life expectancy of 2–5 years from the time of diagnosis. But research from a team led by David Schaffer, professor of bioengineering and chemical and biomolecular engineering, may lead to new therapies and an eventual cure for the disease. Using CRISPR-Cas9 gene editing, the scientists disabled a defective gene that causes ALS in mice, significantly increasing their lifespan. The team used a benign virus to ferry a gene encoding the Cas9 protein into motor neurons in the spinal cord. There, the gene was translated into the Cas9 protein, a molecular scissors that cut and disabled the mutant gene responsible for ALS in the mice. Not only did the therapy delay the onset of the disease, it also extended the lifespan of the mice by 25 percent.
Duchenne muscular dystrophy
Researchers from the laboratories of Berkeley bioengineering professors Niren Murthy and Irina Conboy have developed a new way to deliver CRISPR-Cas9 gene-editing technology inside cells. Called CRISPR-Gold because gold nanoparticles are a key component, their technique can deliver Cas9 — the protein that binds and cuts DNA — along with guide RNA and donor DNA into the cells of a living organism to fix a gene mutation. Viruses are commonly used to deliver CRISPR-Cas9 into cells, but that approach can have complications; CRISPR-Gold does not need viruses and repairs DNA mutations through a process called homology-directed repair. In their study, the researchers showed that a single injection of CRISPR-Gold into mice with Duchenne muscular dystrophy led to an 18-times-higher correction rate and a two-fold increase in a strength and agility test compared to control groups. Duchenne muscular dystrophy, a fatal muscle-wasting disease, affects 1 in 3,500 boys, with 20,000 new cases diagnosed each year worldwide.