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Updated: May 11, 2026
Proteomic Profiling of Macrophages by 2D Electrophoresis
Published on: November 4, 2014
A significant part of macrophage-derived growth factor consists of at least two forms of PDGF
Abstract:
The macrophage has been suggested to be responsible for the connective tissue cell proliferation that accompanies most chronic inflammatory responses. One of the secretory products of activated macrophages is MDGF, a growth factor (or factors) for fibroblasts, 3T3 cells, smooth muscle, and vascular endothelium. This report demonstrates that a significant portion of the mitogenic activity for 3T3 cells secreted by cultured human alveolar and peritoneal macrophages is due to a molecule (or molecules) similar to platelet-derived growth factor (PDGF). Two size classes (approximately 37,000-39,000 and 12,000-17,000 daltons) of mitogenically active PDGF-like molecules are detected by two criteria--antigenic similarity with PDGF and ability to compete with 125I-PDGF for high-affinity binding to the PDGF receptor. The presence of mRNA for the B chain of PDGF is demonstrated by Northern analysis, and de novo synthesis of these molecules by activated macrophages is shown by immunoprecipitation of 35S-labeled proteins with anti-PDGF IgG.
Insights
Activated macrophages secrete platelet-derived growth factor (PDGF)-like molecules that drive cell proliferation during chronic inflammation. These findings reveal a key mechanism in inflammatory responses.
Area of Science:
- Cell Biology
- Immunology
- Molecular Biology
Background:
- Macrophages are implicated in connective tissue cell proliferation during chronic inflammation.
- Macrophages secrete Macrophage-Derived Growth Factor (MDGF), a mitogen for various cell types.
Purpose of the Study:
- To investigate the role of PDGF-like molecules in mitogenic activity secreted by human macrophages.
- To characterize the PDGF-like molecules produced by activated macrophages.
Main Methods:
- Cultured human alveolar and peritoneal macrophages were used.
- Mitogenic activity was assessed using 3T3 cells.
- PDGF-like molecules were detected via antigenic similarity and receptor binding assays.
- Northern analysis detected PDGF B chain mRNA.
- Immunoprecipitation identified de novo synthesis of PDGF-like proteins.
Main Results:
- Human macrophages secrete PDGF-like molecules with mitogenic activity for 3T3 cells.
- Two size classes of PDGF-like molecules (37-39 kDa and 12-17 kDa) were identified.
- These molecules exhibit antigenic similarity to PDGF and bind to the PDGF receptor.
- Macrophages synthesize PDGF B chain mRNA and de novo PDGF-like proteins.
Conclusions:
- Macrophages produce and secrete PDGF-like molecules that contribute to cell proliferation in inflammatory conditions.
- These findings highlight macrophages as a significant source of PDGF-like growth factors, influencing inflammatory tissue responses.
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