Researchers at the German Cancer Research Center (DKFZ) and the HI-STEM Stem Cell Institute have identified a group of blood stem cells in mice that can stay dormant longer than previously recognized cells, while preserving their capacity to generate blood. The findings, published in Cell Stem Cell, suggest this population could help maintain blood production and immune defenses throughout a mouse’s life.
Blood stem cells in bone marrow renew themselves and produce the body’s blood cells. Many remain inactive for extended periods, dividing when needed. The researchers found that some cells previously overlooked because they lack the surface marker CD150 carry another marker, EPCR, and display especially prolonged dormancy.
More than 200 days into the study, around 10% to 15% of the newly identified cells still showed a marker of dormancy, compared with about 2% of conventional blood stem cells. The newly described cells also responded less readily to inflammatory signals, which can prompt stem cells to activate and produce immune cells but may reduce their reserves when activation happens repeatedly.
The two populations showed different tendencies in the types of blood cells they produced. Conventional CD150-positive stem cells were more oriented toward red blood cells and platelets, while the deeply dormant cells more often developed into immune cells, particularly lymphocytes. Both groups could produce all major blood cell types in mouse transplantation experiments. Individual cells from the newly identified population sustained blood production for life, including after serial transplantation.
The researchers say the findings show that blood stem cells comprise distinct subgroups with different properties. A comparable long-lived population has not yet been demonstrated in humans. The team says investigating whether one exists is a next step; better understanding of how stem cells remain functional with age could eventually inform stem cell transplant therapies.
Sources: Phys.org.