can lead to the development of neurodegenerative diseases in individuals with this gene variant. The study suggests that mitochondrial dysfunction plays a key role in the body’s ability to defend against viral infections, and that this dysfunction can ultimately contribute to the development of neurodegenerative diseases.
Different triggers can cause and change symptoms of neurological illnesses in individuals with genetic susceptibility.
The study is published in Nature.
Gene mutation from the Viking age affects defense against viruses
It is still unclear why a disease appears at a specific age and what kind of triggers might be involved. Recent evidence suggests that mitochondria, which are the energy and nutrient metabolism centers of cells, play new crucial roles in protecting cells from both internal and external pressures. Significantly, a new function of mitochondria in enhancing the immune system has been identified, but the relevance of these findings is not yet clear.The link between deficient mitochondrial functions in immune defense and the development of brain diseases and liver dysfunction has been unclear. However, a recent study led by academy professor Anu Suomalainen and her multidisciplinary team has found that a genetic variant affecting the function of the mitochondrial POLG enzyme can delay the detection of viral infections. This delay can lead to a severe inflammatory reaction, causing damage to the brain and liver.
The POLG variant can be traced back to a single individual from Viking times and has since spread to populations of European origin, particularly those from Northern Europe.ean countries have high carrier frequencies, with one in a hundred individuals in Finland and Norway carrying the variant. If someone inherits the POLG-variant from both parents, it can lead to a neurological disease called MIRAS (mitochondrial recessive ataxia syndrome). The onset and symptoms of MIRAS can vary widely, which raises questions about other factors that may trigger the disease.
Through the use of different model systems, the research team found that the POLG variant can result in weakened initial immune response to viral infection, followed by a delayed and overactivated inflammation that can damage the brain and liver. This research sheds light on the potential mechanisms behind MIRAS.suggesting that the reason some MIRAS patients experience severe epilepsy in their teenage years, while others with the same genetic background may show signs of disease much later, such as motor coordination defects or Parkinson’s disease. “Our findings suggest that environmental factors, such as viral infections, can alter the onset and manifestation of neurological diseases,” says postdoctoral scientist Yilin Kang. “Identifying factors that make individuals susceptible and the mechanisms that trigger these diseases are important targets for developing new therapies. These findings highlight the significance of newly discovered mitochondrial functions.”The Jane and Aatos Erkko Foundation, Sigrid Juselius Foundation, Research Council of Finland, European Molecular Biology Organization, and PolG foundation have all contributed to the research on maintaining brain health.