A new mRNA treatment rejuvenates the body's key immune cells, which may help them fight infections and cancer, research in mice suggests.
T cells help train other immune cells to fight disease. But as the body ages, the activity of these T cells decreases, and they become less responsive to threats. In addition, the thymus gland, where T cells mature, begins to shrink with age. These effects of aging may explain why vaccines and immune-boosting cancer treatments do not work as well in older people as they do in younger people. This was reported by Nature News.
Among other things, mRNA carries instructions from DNA to protein-building organelles in cells, serving as the template from which new proteins are created. The team behind the new study examined T cells in aging mice, identifying three proteins that appear to decline with age, contributing to the aging process. They then created mRNA for these three proteins, encased them in tiny bubbles of fat, and injected them into middle-aged mice that were about 16 months old.
These mRNA-filled vesicles traveled through the bloodstream to the liver, where they accumulated. Most T cells are found in the bloodstream, and since the liver filters the 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 mice that were left untreated. The experiments showed that T cells from treated mice also responded better to vaccinations and cancer immunotherapy.
The benefits of the treatment, which was given to the mice twice a week, quickly disappeared when the scientists stopped the injections. This is not surprising given that mRNA molecules degrade very quickly in the body, whether they were originally created by cells or produced in a laboratory.
“The transient nature of mRNA delivery requires repeated administrations to maintain the therapeutic effect,” the study authors wrote in the paper. However, “the long-term consequences of chronic exposure to these factors, especially in older adults, need to be analyzed through extensive long-term safety studies.”
In short, more research is needed to see if the same approach can work in humans. Read more about the study in Nature news.
