Related Experiment Video
Updated: May 22, 2026
Isolation of Murine Peritoneal Macrophages to Carry Out Gene Expression Analysis Upon Toll-like Receptors Stimulation
Published on: April 29, 2015
Bacterial cell wall constituents induce hepcidin expression in macrophages through MyD88 signaling
Antonio Layoun1, Manuela M Santos
1Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Hôpital Notre-Dame, Pav. De Sève Y5625, 1560 rue Sherbrooke est, Montréal, Québec, H2L 4M1, Canada.
Abstract:
Hepcidin is a key regulator of iron recycling by macrophages that is synthesized mainly by hepatocytes but also by macrophages. However, very little is known about the molecular regulation of hepcidin in macrophages. In the present study, we investigated hepcidin regulation in the RAW264.7 macrophage cell line and in murine peritoneal macrophages stimulated with different Toll-like receptor (TLR) ligands. We found that TLR-2 and TLR-4 ligands activated hepcidin expression in RAW264.7 cells and in wild-type murine peritoneal macrophages, but not in murine peritoneal macrophages isolated from TLR2(-/-), TLR-4-deficient or MyD88(-/-) mice. IL-6 production by RAW264.7 cells stimulated with lipopolysaccharide (LPS, TLR4 ligand) was enhanced by high amounts of iron present in the culture medium. We conclude that hepcidin expression in macrophages is regulated mainly through TLR2 and TLR4 receptors via the MyD88-dependent signaling pathway and that autocrine regulation of iron accumulation in macrophages by hepcidin may affect the levels of proinflammatory cytokine production.
Insights
Toll-like receptor (TLR) ligands activate hepcidin expression in macrophages via the MyD88 pathway. This macrophage hepcidin regulation influences iron accumulation and proinflammatory cytokine production.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Hepcidin regulates iron homeostasis and is produced by hepatocytes and macrophages.
- The molecular mechanisms controlling hepcidin synthesis in macrophages remain largely uncharacterized.
Purpose of the Study:
- To investigate the regulation of hepcidin expression in macrophages.
- To elucidate the role of Toll-like receptors (TLRs) in macrophage hepcidin synthesis.
Main Methods:
- Utilized RAW264.7 macrophage cell line and primary murine peritoneal macrophages.
- Stimulated macrophages with various Toll-like receptor (TLR) ligands, including lipopolysaccharide (LPS).
- Assessed hepcidin expression in wild-type and TLR-deficient (TLR2-/-, TLR-4-/-, MyD88-/-) macrophages.
Main Results:
- TLR-2 and TLR-4 ligands significantly induced hepcidin expression in RAW264.7 cells and wild-type macrophages.
- This induction was absent in macrophages lacking TLR2, TLR-4, or MyD88, indicating a MyD88-dependent pathway.
- High iron levels in culture medium enhanced IL-6 production in LPS-stimulated RAW264.7 cells.
Conclusions:
- Macrophage hepcidin expression is primarily regulated by TLR2 and TLR4 receptors through the MyD88 signaling pathway.
- Autocrine regulation of macrophage iron levels by hepcidin may impact the production of proinflammatory cytokines like IL-6.
Related Concept Videos
01:31Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
01:26Gastritis II: Pathophysiology