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Updated: Jul 15, 2026
Culture of Macrophage Colony-stimulating Factor Differentiated Human Monocyte-derived Macrophages
Published on: June 30, 2016
Mouse neutrophilic granulocytes express mRNA encoding the macrophage colony-stimulating factor receptor (CSF-1R) as
R Tedjo Sasmono1, Achim Ehrnsperger, Stephen L Cronau
1CRC for Chronic Inflammatory Diseases and ARC Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia.
Abstract:
The differentiation of macrophages from their progenitors is controlled by macrophage colony-stimulating factor (CSF-1), which binds to a receptor (CSF-1R) encoded by the c-fms proto-oncogene. We have previously used the promoter region of the CSF-1R gene to direct expression of an enhanced green fluorescent protein (EGFP) reporter gene to resident macrophage populations in transgenic mice. In this paper, we show that the EGFP reporter is also expressed in all granulocytes detected with the Gr-1 antibody, which binds to Ly-6C and Ly-6G or with a Ly-6G-specific antibody. Transgene expression reflects the presence of CSF-1R mRNA but not CSF-1R protein. The same pattern is observed with the macrophage-specific F4/80 marker. Based on these findings, we performed a comparative array profiling of highly purified granulocytes and macrophages. The patterns of mRNA expression differed predominantly through granulocyte-specific expression of a small subset of transcription factors (Egr1, HoxB7, STAT3), known abundant granulocyte proteins (e.g., S100A8, S100A9, neutrophil elastase), and specific receptors (fMLP, G-CSF). These findings suggested that appropriate stimuli might mediate rapid interconversion of the major myeloid cell types, for example, in inflammation. In keeping with this hypothesis, we showed that purified Ly-6G-positive granulocytes express CSF-1R after overnight culture and can subsequently differentiate to form F4/80-positive macrophages in response to CSF-1.
Insights
Macrophage colony-stimulating factor (CSF-1) controls macrophage differentiation. Granulocytes can express CSF-1 receptor (CSF-1R) and differentiate into macrophages, suggesting myeloid cell plasticity.
Area of Science:
- Immunology
- Cell Biology
- Hematopoiesis
Background:
- Macrophage differentiation is regulated by CSF-1 binding to CSF-1R.
- Previous studies used CSF-1R promoter to express EGFP in macrophages of transgenic mice.
Purpose of the Study:
- To investigate EGFP expression in granulocytes using CSF-1R promoter.
- To compare mRNA expression profiles of granulocytes and macrophages.
- To explore the potential for myeloid cell interconversion.
Main Methods:
- Transgenic mice expressing EGFP under CSF-1R promoter.
- Antibody staining (Gr-1, Ly-6G, F4/80).
- Comparative array profiling of purified granulocytes and macrophages.
- Overnight culture of purified granulocytes with CSF-1.
Main Results:
- EGFP reporter expressed in granulocytes (Gr-1+, Ly-6G+) and macrophages (F4/80+).
- Transgene expression correlated with CSF-1R mRNA, not protein.
- Distinct mRNA expression patterns identified between granulocytes and macrophages, including specific transcription factors and proteins.
- Purified granulocytes expressed CSF-1R after culture and differentiated into macrophages upon CSF-1 stimulation.
Conclusions:
- CSF-1R promoter directs expression in both macrophages and granulocytes.
- Granulocytes possess the capacity to differentiate into macrophages.
- Myeloid cell plasticity may occur rapidly in response to inflammatory stimuli.
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