Gene therapy is a highly promising frontier in the quest to conquer hereditary diseases. However, despite significant strides in recent years, several obstacles stand in the way of broad adoption of gene therapies. These include efficiently delivering genetic material into target cells using adeno-associated viral vectors (AAVs) with minimal side effects. AAV carrier substances boast an excellent safety profile and high gene transfer efficiency, making them ideal tools in gene therapies and cutting-edge CRISPR/Cas gene editing technologies. Yet, AAVs exhibit a vital deficiency—a limited capacity for DNA uptake and an inability to transport larger genes reliably.

Previously, various methods have been devised to circumvent these issues, often necessitating splitting the coding DNA into two fragments that can later reunite in the target tissue. These strategies, however, proved inefficient and inflexible and caused potential side effects.

The team of Elvir Becirovic, professor of experimental and translational ophthalmology at the University of Zurich, has unveiled a novel approach to circumvent these hurdles. This pioneering method, aptly named REVeRT (reconstitution via mRNA trans-splicing), also employs the principle of dual AAV vectors. Unlike its forerunners, REVeRT enables the assembly of split gene fragments at the transcript level.

“The advantages of this method are increased efficiency and fewer side effects,” explains Becirovic. “It is also more flexible than previous methods, as the large genes can be divided into two fragments at various points.” Becirovic's team has rigorously tested this approach in ophthalmologic applications through cell cultures and animal models under various conditions, including its application in treating hereditary macular degeneration.

REVeRT is not only applicable to ophthalmology. It holds potential for a wide array of genetic and acquired diseases, including common blood disorders and age-related afflictions. This new method can also integrate with gene therapy studies using CRISPR/Cas genome editing. To harness the therapeutic potential of these modules, the coding DNA must be transferred into target cells with maximum efficiency, primarily through the aid of carriers like AAVs.

“With CRISPR/Cas, further applications are possible, opening up new treatment options,” says Becirovic. This ground-breaking advancement might just open new doors in the realm of gene therapy studies and CRISPR/Cas genome editing.