Are Ancient Viruses Causing Psychiatric Disorders?
A New Study from King’s College London Says “Yes”
By Viola Spada
Thousands of DNA sequences from ancient viral infections are expressed in the brain, according to new research headed by King's College London. Some of these sequences may increase a person's risk of developing psychiatric conditions like depression, bipolar disorder, and schizophrenia.
Human Endogenous Retroviruses (HERVs) are sequences that arose from ancient viral infections occurring hundreds of thousands of years ago, and they make up about 8% of the human genome. Previously, these so-called "fossil viruses" were considered "junk" DNA with no bodily function. However, due to advancements in genomics research, scientists have now identified the precise locations of these ancient viruses in our DNA, providing more insight into their potential roles and the conditions under which they are expressed.
To investigate how DNA variations associated with psychiatric disorders impact the expression of HERVs, the study analyzed data from extensive genetic studies involving tens of thousands of individuals, both with and without mental health conditions, as well as information from autopsy brain samples from 800 individuals.
The researchers discovered that certain genetic risk variants tended to alter the expression of HERVs, even though most genetic risk variants associated with mental disorders affected genes with well-known biological roles.
Dr. Rodrigo Duarte, the lead author and Research Fellow at the IoPPN, King's College London, stated: "We know that psychiatric disorders have a substantial genetic component, with many parts of the genome incrementally contributing to susceptibility. In our study, we were able to investigate parts of the genome corresponding to HERVs, which led to the identification of five sequences that are relevant to psychiatric disorders. While it is unclear how these HERVs affect brain cells to confer this increased risk, our findings suggest that their expression regulation is important for brain function."
Dr. Douglas Nixon, a researcher from the US Feinstein Institutes for Medical Research at Northwell Health, stated: "More research is necessary to determine the precise role of the majority of HERVs. We believe that a deeper understanding of these ancient viruses and the genes linked to psychiatric diseases could transform mental health research and result in new approaches to diagnosis and treatment."
Citations:
“Ancient viral DNA in the human genome linked to major psychiatric disorders.” ScienceDaily, 2024, https://www.sciencedaily.com/releases/2024/05/240522130345.htm. Accessed 23 May 2024.
