New gene therapy for eye disease developed

A new gene therapy approach, developed by Irish scientists, could one day treat an eye disease that leads to a progressive loss of vision and affects thousands of people across the globe. The breakthrough has been published in the journal Frontiers in Neuroscience.

Characterised by degeneration of the optic nerves, dominant optic atrophy (DOA) typically starts to cause symptoms in patients in their early adult years. These include moderate vision loss and some colour vision defects, but severity varies, symptoms can worsen over time and some people may become blind. There is currently no way to prevent or cure DOA.

The gene OPA1 provides instructions for making a protein that is found in cells and tissues throughout the body, and which is pivotal for maintaining proper function in mitochondria, which are the energy producers in cells. Without the protein made by OPA1, mitochondrial function is suboptimal and the mitochondrial network which in healthy cells is well interconnected is highly disrupted. For those living with DOA, it is mutations in OPA1 and the dysfunctional mitochondria that are responsible for the onset and progression of the disorder.

Scientists from Trinity College London, collaborating with clinical teams at the Royal Victoria Eye and Ear Hospital and the Mater Misericordiae University Hospital, have now developed a gene therapy that successfully protected the visual function of mice who were treated with a chemical targeting the mitochondria and were consequently living with dysfunctional mitochondria. The scientists also found that their gene therapy improved mitochondrial performance in human cells that contained mutations in the OPA1 gene, offering hope that it may be effective in people.

“We used a clever lab technique that allows scientists to provide a specific gene to cells that need it using specially engineered non-harmful viruses,” said study co-leader Dr Daniel Maloney. “This allowed us to directly alter the functioning of the mitochondria in the cells we treated, boosting their ability to produce energy, which in turn helps protect them from cell damage.”

He added, “Excitingly, our results demonstrate that this OPA1-based gene therapy can potentially provide benefit for diseases like DOA, which are due to OPA1 mutations, and also possibly for a wider array of diseases involving mitochondrial dysfunction.” Mitochondrial dysfunction causes problems in a suite of other neurological disorders, such as Alzheimer’s and Parkinson’s disease.

“Mitochondrial dysfunction is implicated in many neurological disorders that collectively affect millions of people worldwide,” said study co-leader Professor Jane Farrar. “We think there is great potential for this type of therapeutic strategy targeting mitochondrial dysfunction to provide benefit and thereby make a major societal impact.

“We are very excited by the prospect of this new gene therapy strategy, although it is important to highlight that there is still a long journey to complete from a research and development perspective before this therapeutic approach may one day be available as a treatment.”

Image credit: ©iStockphoto.com/Brian Jackson

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