The team from the Immunology Department at Weill Cornell Medical Center in New York has taken another step toward slowing human aging.
Ancient viruses, whose DNA has been carried in the human genome for millennia, may contribute to many age-related diseases. Now scientists have shown for the first time that they can use this viral DNA—known as “retroelements”—to predict the age of human cells with high accuracy.
This seemingly inactive “junk” DNA has been linked to multiple age-related processes, from sleep and memory to conditions such as bipolar disorder.
Armed with the new ability to track a person’s age using ancient viral DNA, researchers plan to investigate whether antiviral treatments can slow aging by deactivating the most harmful retroelement genes.
Insights from the Researchers
Previous studies have shown that about 8 percent of the human genome is made up of viral sequences similar to the retroelements that form the basis of this research.
The team used previously unknown features of ancient viral DNA to build a biological clock that tracks human age based on chemical changes in DNA.
Researchers suggest that new antiretroviral treatments, similar to drugs used against HIV/AIDS, could one day help reverse some signs of aging.
“Our results showed that the retroelement clock captures previously undetected aspects of biological aging,” said Dr. Michael Corley, a co-author of the study. He added that the new age-calculation method—Retro-Age—”could open doors to future treatments for various age-related diseases.”
The foundation of this age-determination method is a process called methylation. Methylation adds a methyl group—a chemical marker—to DNA, which can change gene activity. Changes in these chemical markers on certain ancient viral retroelements are likely linked to inflammation, genomic instability, and some age-related diseases.
The study used a machine-learning model developed by the medical firm TruDiagnostic of Kentucky to track DNA methylation. The model was trained on DNA data from about 12,670 people between the ages of 12 and 100.
The reactivation of certain retroelements increases with age, which can lead to biological signs of aging, Dr. Corley explained. He also noted that cellular senescence, when cells stop dividing, is likely associated with activated ancient viral DNA.
Key Takeaways
Researchers believe that treatments capable of stopping the activation of ancient viral DNA could slow many physical symptoms of aging.
Dr. Corley and his colleagues’ Retro-Age method has shown promising results in at least two areas.
First, it has helped more accurately identify and document when a person’s biological age diverges from their chronological age.
Second, the work suggests an anti-aging effect from antiretroviral drugs similar to those used to treat HIV/AIDS.
The team now hopes to conduct further research to determine whether these treatments have a similar rejuvenating effect in people without HIV or other immunosuppressive infections.
The study’s findings were published in the journal Aging Cell.
