Our blood consists of many types of cells that are developed through different stages from a precursor type: blood stem cells. An international research team led by Universitätsmedizin Frankfurt and Goethe University has now investigated the development paths of blood cells in humans. The results produced a surprise: even stem cells have superficial proteins that allow them to suppress the activation of inflammatory and immune responses in the body. This finding is particularly relevant to stem cell transplants, requested for the treatment of leukemia for example.
Every second, an adult generates around five million new blood cells to replace aging or dying, which makes the blood system a highly regenerative organ. These new blood cells are formed in the bone marrow from non -specialized cells, known as blood cells. Through several intermediate stages, these stem cells become erythrocytes that transport oxygen, platelets that coincide with the blood and the large group of white blood cells that orchestrate immune defense. This process, known as differentiation, must be accurately regulated to guarantee a balanced production of mature blood cells in all types of cells.
An International Team of Scientists at the University of Universitätsmedizin Frankfurt/Goethe, the University of Gothenburg, and the Pamplona University Hospital, directed by Prof. Michael Rieger of the University of the University Frankfurt Department of Medicine II, now has molecularly decoded the differentiation routes of the cells of the semáreos of human blood in all types of blood specialized. Using latest generation sequencing methods, the research team identified genes and protein expression patterns in more than 62,000 individual cells and analyzed the resulting data with high performance computing.
“We were able to obtain an overview of molecular processes in stem cells and discover new superficial proteins that are crucial for complex interaction between stem cells and their bone marrow environment,” Rieger explains. “This provides us with detailed information on which exactly the unique characteristics of a stem cell and what genes regulate stem cell differentiation. This technology recently established in my laboratory will answer many unresolved questions in health research with extraordinary precision.”
The researchers discovered an unexpected finding: “We found a protein called PD-L2 on the surface of blood stem cells, which we know that suppresses the immune response of our defense cells, T cells, by preventing their activation and proliferation and inhibiting the release of inflammatory substances called cytokines called cytokines, summarizes the first author of the study, student of PhD Schmachteel.
PD-L2 probably serves to prevent immunomedized damage, explains the biologist Schmachtel. “This is particularly important to protect stem cells from possible attacks by reactive T cells and probably plays a key role in stem cell transplants with unrelated donor grafts. PD-L2 could help reduce the body’s immune response against transplanted stem cells.”
Rieger is convinced: “Innovative discoveries can only be made on the basis of a close interdisciplinary collaboration between doctors, scientists and bioinformatics, as practiced at Universitätsmedizin Frankfurt, and through the establishment of international networks.”