Breakthrough for DNA-editing: US team discovers 'holy grail' to fix genes to cure incurable diseases

Scientists have discovered how to edit DNA to repair 'broken genes' to cure incurable diseases - and potentially extend human lifespan. Until now, it has not been possible to alter genes in the brain, heart, liver and eyes - the root of many debilitating illnesses. Since the cells in these vital organs tend not to divide, it is difficult to gain access to make changes. However, researchers at the Salk Institute claim to have landed on 'the holy grail of gene editing', which can delicately and smoothly cut through DNA. So far the technique, called HITI, has been used to successfully restore blindness in lab mice. Lead researcher Professor Juan Carlos Izpisua Belmonte insists that is nothing compared to the changes the technique could have in the decades to come. 'We are very excited by the technology we discovered because it's something that could not be done before,' Dr Belmonte said. '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.' News of the discovery comes a day after Chinese scientists successfully tested a similar DNA-modifying technique, known as CRISPR. To date, CRISPR has been the most effective method for dividing cells in large organs like the skin or the gut. It uses the cells' normal copying mechanisms, allowing DNA to be inserted and incorporated into very precise locations within the genome. However, Salk's investigators say their technology is ten times more efficient at incorporating new DNA into cultures of dividing cells. It means it is a promising tool for both research and medicine. Crucially, it marks the first time scientists have managed to insert a new gene into a precise DNA location in adult cells that no longer divide, such as those of the eye, brain, pancreas or heart. The landmark procedure offers swathes of new possibilities for disease treatment. The researchers were working on rats who were born with retinitis pigmentosa, a genetic disease that causes blindness. They targeted a DNA-repair pathway, which repairs standard DNA breaks by rejoining the original strand ends. Next, they used this pathway, and existing gene-editing technology, to insert new DNA into a precise location in non-dividing cells. After the procedure, the rats had regained a significant amount of their vision. 'No one has done this before,' Keiichiro Suzuki, a senior research associate in the Izpisua Belmonte lab and one of the paper's lead authors, said. The team's next steps will be to improve the delivery efficiency of the HITI construct. As with all genome editing technologies, getting enough cells to incorporate the new DNA is a challenge. The beauty of HITI technology is that it can adapt to any kind of gene-editing technique and machinery, not just CRISPR. '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,' says 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.' Read more: Follow us: @MailOnline on Twitter | DailyMail on Facebook