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Updated: May 7, 2026
Generation and Identification of GM-CSF Derived Alveolar-like Macrophages and Dendritic Cells From Mouse Bone Marrow
Published on: June 25, 2016
Establishment of self-renewable GM-CSF-dependent immature macrophages in vitro from murine bone marrow
Sachiko Ito1, Yuriko Tanaka, Naomi Nishio
1Department of Immunology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Abstract:
Macrophages play a key role in the innate immune system. Macrophages are thought to originate from hematopoietic precursors or the yolk sac. Here, we describe the in vitro establishment of self-renewable GM-CSF-dependent immature macrophages (GM-IMs) from murine bone marrow (BM). GM-IMs grow continuously in vitro in conditioned medium containing GM-CSF. The immunophenotype of GM-IMs is F4/80(high) CD11b(high) CD11c(low) Ly6C(low). By comparing gene expression in GM-IMs and BM dendritic cells, we found that GM-IMs expressed lower levels of chemokines, cytokines and their receptors. GM-IMs are round in shape, attach loosely to non-coated culture dishes and have a marked phagocytic capacity. These results indicate that GM-IMs are macrophage precursor cells. Following stimulation with LPS, monocyte-like GM-IMs converted to flat macrophage-like cells that tightly adhered to non-coated culture dishes and produced pro-inflammatory cytokines TNFα, IL-6 and IL-1β. These results indicated that GM-IMs differentiated to M1 pro-inflammatory macrophages. This was confirmed by stimulation of GM-IMs with IFNγ, an inducer of M1 markers. GM-IMs showed enhanced expression of M2 macrophage markers such as Arg1 and Retnla following stimulation by Th2 cytokines IL-4 and IL-13. When GM-IMs were injected into mice at sites of wounding, wound repair was enhanced. These results indicate that GM-IMs can differentiate to M2 macrophages. When GM-IMs were injected into clodronate-treated mice, they induced resident macrophage proliferation by producing M-CSF. In conclusion we have established self-renewable GM-CSF-dependent immature macrophages in vitro from murine BM, which differentiate to M1 or M2 macrophages.
Insights
Researchers established self-renewable immature macrophages (GM-IMs) from mouse bone marrow. These macrophage precursors can differentiate into M1 or M2 types and enhance wound repair in vivo.
Area of Science:
- Immunology
- Cell Biology
Background:
- Macrophages are crucial innate immune cells originating from hematopoietic precursors or the yolk sac.
- Understanding macrophage development and differentiation is key to modulating immune responses.
Purpose of the Study:
- To establish and characterize self-renewable immature macrophage precursors in vitro from murine bone marrow.
- To investigate the differentiation potential of these precursors into M1 and M2 macrophages.
- To assess the in vivo effects of these precursors on wound repair and resident macrophage populations.
Main Methods:
- Isolation and culture of immature macrophages (GM-IMs) dependent on granulocyte-macrophage colony-stimulating factor (GM-CSF) from murine bone marrow.
- Immunophenotyping (F4/80, CD11b, CD11c, Ly6C) and gene expression analysis of GM-IMs.
- Stimulation of GM-IMs with lipopolysaccharide (LPS), interferon-gamma (IFNγ), and Th2 cytokines (IL-4, IL-13) to induce differentiation.
- In vivo studies involving injection of GM-IMs into mouse wound sites and clodronate-treated mice.
Main Results:
- Established continuously growing, self-renewable, immature macrophages (GM-IMs) from murine bone marrow.
- GM-IMs exhibit a distinct immunophenotype and phagocytic capacity, identifying them as macrophage precursors.
- GM-IMs successfully differentiated into M1 pro-inflammatory macrophages upon LPS/IFNγ stimulation and M2 macrophages upon IL-4/IL-13 stimulation.
- In vivo administration of GM-IMs enhanced wound repair and promoted resident macrophage proliferation via M-CSF production.
Conclusions:
- Successfully established self-renewable, GM-CSF-dependent immature macrophages (GM-IMs) in vitro from murine bone marrow.
- GM-IMs serve as versatile macrophage precursors capable of differentiating into both M1 and M2 phenotypes.
- These findings highlight the potential therapeutic applications of GM-IMs in wound healing and immune modulation.
