Breakthrough Gene-Editing Study Returns Sight to Blind Animals

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In a breakthrough that may peek into the future of gene-editing potential, scientists have figured out a way to manipulate the DNA within non-dividing adults cells – a technique that may prove especially useful against a variety of genetic diseases.

Proving the efficacy of the new technology, the researchers were able to restore sight in genetically blind rodents, according to the study appearing in the journal Nature.

Credit: Salk Institute
Credit: Salk Institute

Both the revolutionary process and the results already gained in animal studies may augur much greater things to come. “We are very excited by the technology we discovered because it’s something that could not be done before,” said Juan Carlos Izpisua Belmonte, a professor at the Salk Institute’s Gene Expression Laboratory and senior author of the paper.

“For the first time, we can enter into cells that do not divide and modify the DNA at will. The possible applications of this discovery are vast,” he said.

The breakthrough methodology

Non-dividing cells comprise the majority of the body’s organs and tissues, yet prior to this study no viable method existed to reach these vital building blocks. The lack of direct reach to non-dividing cells posed “a barrier for uncovering fundamental biological principles and developing treatments for a broad range of genetic disorders,” wrote the researchers.

Most studies previously focused on dividing cells, which have proven easier to manipulate.

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Pictured is a part of the adult mouse brain. Cell nuclei are blue and genome-edited neurons are green. Caption/Image Credit: Salk Institute

Yet the new research may push aside those barriers forever. Building on known gene-editing technology, the research team focused their sights on a specific DNA repair process called non-homologous end-joining (NHEJ), which occurs when cellular mechanisms repair normal breaks in the DNA by rejoining the end strands.

The major breakthrough is that researchers discovered a way to execute gene-editing technology during this complex repair process. “Using this NHEJ pathway to insert entirely new DNA is revolutionary for editing the genome in live adult organisms,” said Keiichiro Suzuki, a senior research associate and co-author. “No one has done this before.”

In the study on rats, the researchers studied those animals with a genetically engineered form of blindness known as retinitis pigmentosa, a condition that affects about one in 4,000 people. The researchers injected a virus containing specific gene-editing instructions into the retinal cells of the blind rodents when they were three weeks old.

At eight weeks, the rats responded to light. Further tests showed that their retinal cells were healing. “We were able to improve the vision of these blind rats,” said co-lead author Reyna Hernandez-Benitez, also of the Salk Institute. “This early success suggests that this technology is very promising.”

Vast implications

The researchers hope that human trials can begin within one or two years, and the new discovery already has tremendous implications on a multitude of genetic and acquired disease states.

“We now have a technology that allows us to modify the DNA of non-dividing cells, to fix broken genes in the brain, heart and liver,” said Izpisua Belmonte. “It allows us for the first time to be able to dream of curing diseases that we couldn’t before, which is exciting.”

Richard Scott

Richard Scott is a health care reporter focusing on health policy and public health. Richard keeps tabs on national health trends from his Philadelphia location and is an active member of the Association of Health Care Journalists.