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Isolation of Mouse Megakaryocyte Progenitors
Published on: May 20, 2021
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Megakaryocytes regulate hematopoietic stem cell quiescence through CXCL4 secretion
Ingmar Bruns1, Daniel Lucas2, Sandra Pinho2
11] Ruth L. and David S. Gottesman Institute for Stem Cell and Regenerative Medicine Research, Albert Einstein College of Medicine, Bronx, New York, USA. [2] Department of Hematology, Oncology and Clinical Immunology, Heinrich Heine University, Düsseldorf, Germany. [3] Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, USA.
Nature Medicine
|October 20, 2014
Summary
Mature megakaryocytes directly regulate hematopoietic stem cells (HSCs) in the bone marrow niche. These cells produce CXCL4, a molecule that controls HSC proliferation and quiescence, ensuring proper blood cell replenishment without exhausting stem cells.
Area of Science:
- Hematology
- Stem Cell Biology
- Microenvironment Research
Background:
- Hematopoietic stem cells (HSCs) reside in specialized bone marrow niches.
- Niche interactions regulate HSC proliferation and prevent exhaustion.
- The origin of feedback signals from mature cells to HSCs remains unclear.
Purpose of the Study:
- To investigate the role of megakaryocytes (MKs) in regulating HSC pool size.
- To identify the mechanisms by which mature cells communicate with HSCs.
- To determine if HSC-derived cells contribute to the HSC niche.
Main Methods:
- Three-dimensional whole-mount imaging of mouse bone marrow.
- In vivo depletion of MKs.
- Gene expression analysis.
- CXCL4 injection and analysis in mice.
- Computational modeling.
Main Results:
- HSCs are frequently located adjacent to MKs in a nonrandom pattern.
- MK depletion leads to loss of HSC quiescence and expansion of functional HSCs.
- MKs are the source of chemokine CXCL4 in the bone marrow.
- CXCL4 regulates HSC cell cycle activity, promoting quiescence.
- Cxcl4(-/-) mice show increased HSC numbers and proliferation.
Conclusions:
- Megakaryocytes directly regulate HSC pool size and behavior.
- CXCL4 produced by MKs is a key regulator of HSC quiescence.
- Terminally differentiated cells, like MKs, can contribute to the HSC niche, influencing HSC maintenance.
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