The human body has an efficient system of preventing and fighting infections, which is provided by immune cells. Research by scientists from the Institute of Molecular Genetics of the Czech Academy of Sciences (IMG) has shown that in addition to these cells, haematopoietic stem cells also respond to acute threats. Experts have so far confirmed this in animal models. The findings could help in the future to understand how to optimise immune responses and prevent sepsis.
The immune system is responsible for keeping the body healthy by producing immune cells. Immune cells such as granulocytes, B-lymphocytes and T-lymphocytes are responsible for eliminating and removing pathogens – germs or disease-causing agents.
However, scientists have recently posed the question of whether the protection of the body is mediated solely by mature immune cells, or whether other cell types may also be involved.
Acute infections that are not dealt with quickly and effectively can lead to more serious conditions such as sepsis. Sepsis is usually prevented by activating a rapid and acute response to the infectious agent, a process known as emergency granulopoiesis. Scientists at the IMG have been studying emergency granulopoiesis for almost a decade and have confirmed that, in addition to the essential role of immune cells, haematopoietic stem cells are also activated in response to the presence of pathogens and have elucidated the mechanisms of this activation. The results of the study were published in the prestigious journal The EMBO Journal.
Stem cells in bone marrow change their identity when threatened
“We knew that haematopoietic stem cells had all the tools to detect germs in our bodies, but we didn’t understand why and how this would affect them,” explains Meritxell Alberich Jordà from the Laboratory of Haematooncology at the IMG. Her team’s results suggest that haematopoietic stem cells in the bone marrow are able to change their identity and thus promote the production of granulocytes, which are necessary to eradicate the external pathogen.
“Blood-forming stem cells decide to change their fate and compromise their daily tasks to help fight infections. We were surprised that cells whose job is to maintain haematopoiesis throughout our lifetime would be so flexible and able to use such sophisticated mechanisms to destroy germs,” says Karolina Vanickova, a scientist at the IMG who conducted the research.
The scientists reached these conclusions using animal models, but future experiments will need to verify the findings in humans. “In the future, we hope these findings will help us understand how to optimise our immune responses and develop strategies to prevent sepsis,” says Meritxell Alberich Jordà
Vanickova K, Milosevic M, Ribeiro Bas I, Burocziova M, Yokota A, Danek P, Grusanovic S, Chiliński M, Plewczynski D, Rohlena J, Hirai H, Rohlenova K, Alberich-Jorda M: Hematopoietic stem cells undergo a lymphoid to myeloid switch in early stages of emergency granulopoiesis. EMBO J 2023, e113527. [pubmed] [doi]
Image showing the mode of functioning of hematopoietic stem cells (HSCs) was created with BioRender.com.