Emergency granulopoiesis is the enhanced and accelerated production of granulocytes that occurs during acute infection. The contribution of hematopoietic stem cells (HSCs) to this process was reported; however, how HSCs participate in emergency granulopoiesis remains elusive. Here, using a mouse model of emergency granulopoiesis we observe transcriptional changes in HSCs as early as 4 h after lipopolysaccharide (LPS) administration. We observe that the HSC identity is changed towards a myeloid-biased HSC and show that CD201 is enriched in lymphoid-biased HSCs. While CD201 expression under steady-state conditions reveals a lymphoid bias, under emergency granulopoiesis loss of CD201 marks the lymphoid-to-myeloid transcriptional switch. Mechanistically, we determine that lymphoid-biased CD201 HSCs act as a first response during emergency granulopoiesis due to direct sensing of LPS by TLR4 and downstream activation of NF-κΒ signaling. The myeloid-biased CD201 HSC population responds indirectly during an acute infection by sensing G-CSF, increasing STAT3 phosphorylation, and upregulating LAP/LAP* C/EBPβ isoforms. In conclusion, HSC subpopulations support early phases of emergency granulopoiesis due to their transcriptional rewiring from a lymphoid-biased to myeloid-biased population and thus establishing alternative paths to supply elevated numbers of granulocytes.
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http://dx.doi.org/10.15252/embj.2023113527 | DOI Listing |
J Leukoc Biol
November 2024
Immunology Center of Georgia, Augusta University, 1410 Laney Walker Blvd, Augusta, GA 30912, United States.
Neutrophils are traditionally viewed as uncomplicated exterminators that arrive quickly at sites of infection, kill pathogens, and then expire. However, recent studies employing modern transcriptomics coupled with novel imaging modalities have discovered that neutrophils exhibit significant heterogeneity within organs and have complex functional roles ranging from tissue homeostasis to cancer and chronic pathologies. This has revised the view that neutrophils are simplistic butchers, and there has been a resurgent interest in neutrophils.
View Article and Find Full Text PDFJ Inflamm (Lond)
October 2024
Department of Anesthesiology, Surgical Intensive Care Medicine and Pain Medicine, Mannheim Institute of Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
Front Immunol
July 2024
Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD, United States.
While most of the cancer immunotherapy strategies engage adaptive immunity, especially tumor-associated T cells, the small fraction of responding patients and types of cancers amenable, and the possibility of severe adverse effects limit its usage. More effective and general interventions are urgently needed. Recently, a de facto innate immune memory, termed 'trained immunity', has become a new research focal point, and promises to be a powerful tool for achieving long-term therapeutic benefits against cancers.
View Article and Find Full Text PDFJ Biol Chem
August 2024
Division of Hematology-Oncology, Department of Medicine, Northwestern University, Chicago, Illinois, USA; Division of Hematology-Oncology, Department of Medicine, Jesse Brown VA Medical Center, Chicago, Illinois, USA. Electronic address:
Fanconi anemia (FA) is an inherited disorder of DNA repair due to mutation in one of 20+ interrelated genes that repair intrastrand DNA crosslinks and rescue collapsed or stalled replication forks. The most common hematologic abnormality in FA is anemia, but progression to bone marrow failure (BMF), clonal hematopoiesis, or acute myeloid leukemia may also occur. In prior studies, we found that Fanconi DNA repair is required for successful emergency granulopoiesis; the process for rapid neutrophil production during the innate immune response.
View Article and Find Full Text PDFCell Mol Immunol
August 2024
Molecular Signaling and Cell Death Unit, VIB-UGent Center for Inflammation Research, Flanders Institute for Biotechnology, Ghent, Belgium.
Acute systemic inflammation critically alters the function of the immune system, often promoting myelopoiesis at the expense of lymphopoiesis. In the thymus, systemic inflammation results in acute thymic atrophy and, consequently, impaired T-lymphopoiesis. The mechanism by which systemic inflammation impacts the thymus beyond suppressing T-cell development is still unclear.
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