Gene therapy in mitochondria
Mitochondria are the energy stations of a cell that have their own DNA. Mutations of mitochondrial DNA (mtDNA) underlie a huge variety of diseases, such as, for example, MELAS syndrome (mitochondrial encephalomyopathy) – a severe multisystem disorder characterized by a gradual loss of motor and mental abilities. Each cell contains a huge number of mitochondria, and if most of them do not have a pathogenic mutation, then a person will be healthy. In order for the disease to manifest, it is necessary that about 60% of mitochondria have the corresponding DNA damage, and the higher this percentage is, the more severe the disease will be. Accordingly, if you reduce the amount of mutated mitochondrial DNA, then the disease can be, if not defeated, then at least ease its course.
Mitochondrial diseases are currently untreatable. However, there is a technique of mitochondrial replacement, which allows those suffering from mitochondrial diseases to have children and not transmit diseases to them. The essence of the method is to carry out the procedure of in vitro fertilization in combination with the replacement of the mitochondria of the egg or embryo with donor ones.
A group of scientists from the University of Cambridge has developed a technique to reduce the amount of damaged mtDNA in the cells of a living organism. The point is to introduce a nuclease enzyme into the cell, which has an "address tag" – zinc fingers (mtZFN) capable of recognizing certain sequences in mtDNA and contacting them, allowing the nuclease to cut out a defective section of DNA. Testing of this method was carried out on mice with signs of heart-affecting mitochondrial disease. To do this, mtZFN was injected into the bloodstream using adenoassociated viruses. According to the results of the study, it was found that in the heart cells of sick mice, the number of mutant mtDNA significantly decreased, as well as improved cardiac activity.
The researchers hope that the results of their work will form the basis of future clinical trials and will allow us to develop an approach to the treatment of various mitochondrial diseases in humans.
Article by Gammage et al. Genome editing in mitochondria corrects a pathogenic mtDNA mutation in vivo published in Nature Medicine.
Anastasia Poznyak, portal "Eternal Youth" http://vechnayamolodost.ru / based on the materials of the University of Cambridge: Mitochondrial diseases could be treated with gene therapy, study suggests.