An experimental mRNA treatment counters immune cell aging in mice
A new mRNA treatment rejuvenates the body’s key immune cells, which could help them fight infections and cancer, a study in mice suggests.
T cells help other immune cells fight disease. But as the body ages, the activity of these T cells decreases and they become less reactive to threats. Additionally, the thymus – where T cells mature – begins to shrink with age. These impacts of aging may explain why vaccines and immune-boosting cancer therapies don’t work as well in older adults as they do in younger adults, Nature News reported.
Among other roles, mRNA relays instructions from DNA to cells’ protein-building organelles, serving as a template from which new proteins are made. The team behind the new study studied T cells in aging mice, identifying three proteins that appeared to decline with age, contributing to the aging process. They then generated mRNA for these three proteins, enclosed them in tiny fat bubbles, and injected them into middle-aged mice, around 16 months old.
These mRNA-filled bubbles traveled through the bloodstream to the liver, where they accumulated. Most T cells are found in the bloodstream, and because the liver filters blood, the T cells likely passed through the liver, where they were exposed to this waiting supply of mRNA.
Mice treated with mRNA produced more T cells than untreated mice. T cells from treated mice also responded better to vaccination and cancer immunotherapy, the experiments suggest.
The benefits of the treatment, given to the mice twice a week, quickly disappeared when the scientists stopped the injections. This is not necessarily surprising, given that mRNA molecules break down very quickly in the body, whether they were originally made by cells or in the laboratory.
“The transient nature of mRNA administration requires repeated administrations to maintain therapeutic effects,” the study authors write in the article. That said, “the long-term consequences of continued exposure to these factors, particularly in older adults, should be analyzed through comprehensive long-term safety studies.”
In short, more research is needed to see if the same approach could work in humans. You can read more about the study in Nature News.
