Scientists have looked inside living stem cells

The study is based on an advanced type of ribosome profiling. This approach allows scientists to identify which messenger RNAs are currently being converted into proteins within a cell. Essentially, the researchers have created a map of the production processes occurring in different tissues at different stages of an organism’s life. Although the experiments were conducted using a mouse model, the findings have significant implications for understanding human aging.

Stem cells possess two key characteristics: they can self-renew indefinitely and differentiate into various cell types. Their uniqueness is largely determined by their special mode of operation: despite their high activity in creating ribosomes (cellular factories for protein assembly), their overall level of protein synthesis is quite low. This, according to experts, supports their “stemness” — the ability to remain undifferentiated until the right moment.

However, as we age, the picture changes. The study revealed that as cells age, they reconfigure their internal processes. Their overall pattern of protein synthesis transforms, which directly affects the regenerative capabilities of the tissue. In particular, the scientists recorded a decrease in the E-cadherin signal in old epidermal cells, which may be one of the markers of their loss of functional properties.

It is noteworthy that in their youth, stem cells do not work at full capacity, and their ribosomes are not loaded with continuous production. This moderation is part of the mechanism for maintaining stemness. However, as the years pass, the balance is disrupted, and the cells lose their ability to maintain an optimal mode of protein synthesis.

These findings not only shed light on the mechanisms of skin aging, but also open up new avenues for research. The single-cell ribosome profiling method can be adapted to study other tissues, although this will require additional protocol adjustments. According to Dr. Clara Dure, the lead author of the study, understanding how stem cells age in different organs will help develop more targeted strategies for maintaining the body’s regenerative potential in the future.