Scientists discover the fountain of youth in blood cells

The levels of cyclophilin A, shown here in red, decline as hematopoietic stem cells age. Credit: Nature Cell Biology (2024).

Blood-forming stem cells, known as hematopoietic stem cells (HSCs), are essential for creating the billions of new blood cells our bodies need daily.

These stem cells are unique because they can last for a very long time, helping to produce red blood cells for oxygen, white blood cells for fighting diseases, and platelets for blood clotting.

Researchers at Baylor College of Medicine have uncovered why these stem cells can live so long and continue to work effectively without showing signs of aging.

Published in Nature Cell Biology, their study reveals that an enzyme called cyclophilin A is crucial for keeping these cells young and functional.

HSCs are usually inactive in the bone marrow but can spring into action when needed to replenish blood cells.

Over time, most cells accumulate old proteins that can clump together, causing harm and leading to aging.

Cells that divide frequently, like progenitor cells that come from HSCs, can get rid of these old proteins easily. However, HSCs don’t divide often, so they face a bigger challenge in dealing with these protein build-ups.

The study, led by Dr. André Catic and Dr. Lauren Maneix, shows that HSCs use cyclophilin A to manage this issue.

Cyclophilin A acts like a helper that ensures proteins maintain their proper shapes and avoid clumping, which can lead to aging and dysfunction.

Using mice for their experiments, the researchers observed that cyclophilin A is abundantly present in young HSCs but decreases in older ones.

By removing cyclophilin A from young HSCs, they noticed these cells aged faster. Conversely, adding cyclophilin A back into older HSCs helped restore their function.

The team also explored how cyclophilin A interacts with certain types of proteins that naturally shift their shapes to perform different functions.

These proteins are prone to sticking together and forming clumps. Cyclophilin A helps these flexible proteins perform their roles correctly and prevents them from aggregating.

By understanding the interaction between cyclophilin A and these flexible proteins, the researchers have provided new insights into how stem cells can resist the effects of aging.

This discovery is not only important for understanding how our body maintains healthy blood cells but could also lead to advances in treatments for aging-related diseases and conditions.

Dr. Catic emphasized the significance of this study for cancer treatment and other clinical applications, suggesting that enhancing the function of cyclophilin A could be a key strategy in medical research focused on prolonging the health and vitality of stem cells.