Related Experiment Video
Updated: Feb 10, 2026
Investigation of Macrophage Polarization Using Bone Marrow Derived Macrophages
Published on: June 23, 2013
[Interferon regulatory factor 5(IRF5) regulates the differentiation of bone marrow-derived macrophages in mice]
Objective:
To investigate the expression differences of interferon regulatory factor 5( IRF5) between M1 and M2 macrophages derived from mouse bone marrow and the effects of small interfering RNA targeting IRF5 gene( IRF5siRNA) on macrophage differentiation.
Methods:
With the treatment of IFN-γ and lipopolysaccharide( LPS),mouse bone marrow-derived macrophages were differentiated into M1 macrophages; while with the treatment of IL-4,mouse bone marrow-derived macrophages were differentiated into M2 macrophages. Differentiation efficiency was measured by flow cytometry. The expressions of IRF5,IL-12,tumor necrosis factor-α( TNF-α),inducible nitric oxide synthase( i NOS),arginase 1( Arg1),macrophage mannose receptor( MMR) mRNAs in M1 and M2 macrophages were analyzed by quantitative real-time PCR( RT-PCR). Furthermore,macrophages were infected with IRF5 siRNA,and then the mRNA expressions of the above proteins in M1 and M2 were tested by RT-PCR,and the protein expressions were detected by Western blotting.The results were analyzed to evaluate the polarization state of macrophages.
Results:
The differentiation proportion of macrophages measured by flow cytometry was 81. 7%. RT-PCR showed that the expressions of IRF5,IL-12,i NOS mRNAs were obviously higher in M1 macrophages than in M2,and TNF-α mRNA was also higher in M1 macrophages. The expressions of Arg1,MMR mRNAs were obviously higher in M2 macrophages than in M1 macrophages. After silencing the IRF5 by IRF5 siRNA,the expressions of IRF5, IL-12, TNF-α and i NOS mRNAs decreased remarkably in macrophages, while the expressions of Arg-1,MMR mRNAs increased. Western blotting revealed that the expressions of IRF5,IL-12,TNF-α and i NOS proteins were significantly reduced,while the expressions of Arg1 and MMR protein were raised. The polarization of macrophages shifted to M2 state.
Conclusion:
IRF5 can be used as an important marker to identify M1 and M2 macrophages,and it has an important role in the regulation of macrophage differentiation.
Insights
Interferon regulatory factor 5 (IRF5) is differentially expressed in M1 and M2 macrophages. Silencing IRF5 promotes M2 macrophage differentiation, indicating its role in regulating macrophage polarization.
Area of Science:
- Immunology
- Cell Biology
Background:
- Macrophages play crucial roles in immune responses and can polarize into distinct subtypes, M1 (pro-inflammatory) and M2 (anti-inflammatory).
- Interferon regulatory factor 5 (IRF5) is a transcription factor involved in immune regulation, but its specific role in macrophage polarization is not fully elucidated.
Purpose of the Study:
- To investigate the differential expression of IRF5 in M1 and M2 macrophages derived from mouse bone marrow.
- To determine the effect of IRF5 gene silencing using small interfering RNA (siRNA) on macrophage differentiation and polarization.
Main Methods:
- Mouse bone marrow-derived macrophages were differentiated into M1 (using IFN-γ and LPS) and M2 (using IL-4) phenotypes.
- Gene and protein expression levels of IRF5, M1 markers (IL-12, TNF-α, iNOS), and M2 markers (Arg1, MMR) were analyzed using RT-PCR and Western blotting.
- Macrophage polarization was assessed by flow cytometry and molecular marker analysis.
Main Results:
- IRF5, IL-12, TNF-α, and iNOS mRNA and protein levels were significantly higher in M1 macrophages compared to M2 macrophages.
- Arg1 and MMR mRNA and protein levels were significantly higher in M2 macrophages compared to M1 macrophages.
- Silencing IRF5 with IRF5 siRNA led to decreased expression of M1 markers and increased expression of M2 markers, shifting macrophage polarization towards the M2 phenotype.
Conclusions:
- IRF5 expression is significantly higher in M1 macrophages than in M2 macrophages.
- IRF5 plays a crucial role in regulating macrophage differentiation and polarization, acting as a key factor in promoting the M1 phenotype.
Related Concept Videos
02:23Master Transcription Regulators
02:02Cis-regulatory Sequences
02:02Cis-regulatory Sequences
02:16Transcription Factors
01:22Bone Marrow Sampling and Transplants
The transplant begins with high doses of chemotherapy and radiation treatment, which aim to destroy...
01:46Epigenetic Regulation