Related Experiment Video
Updated: Mar 13, 2026
Metabolic Characterization of Polarized M1 and M2 Bone Marrow-derived Macrophages Using Real-time Extracellular Flux Analysis
Published on: November 28, 2015
Mitochondrial Dysfunction Prevents Repolarization of Inflammatory Macrophages
Jan Van den Bossche1, Jeroen Baardman1, Natasja A Otto2
1Department of Medical Biochemistry, Experimental Vascular Biology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105, the Netherlands.
Abstract:
Macrophages are innate immune cells that adopt diverse activation states in response to their microenvironment. Editing macrophage activation to dampen inflammatory diseases by promoting the repolarization of inflammatory (M1) macrophages to anti-inflammatory (M2) macrophages is of high interest. Here, we find that mouse and human M1 macrophages fail to convert into M2 cells upon IL-4 exposure in vitro and in vivo. In sharp contrast, M2 macrophages are more plastic and readily repolarized into an inflammatory M1 state. We identify M1-associated inhibition of mitochondrial oxidative phosphorylation as the factor responsible for preventing M1→M2 repolarization. Inhibiting nitric oxide production, a key effector molecule in M1 cells, dampens the decline in mitochondrial function to improve metabolic and phenotypic reprogramming to M2 macrophages. Thus, inflammatory macrophage activation blunts oxidative phosphorylation, thereby preventing repolarization. Therapeutically restoring mitochondrial function might be useful to improve the reprogramming of inflammatory macrophages into anti-inflammatory cells to control disease.
Insights
Inflammatory (M1) macrophages resist reprogramming into anti-inflammatory (M2) cells due to inhibited mitochondrial function. Restoring this function may help treat inflammatory diseases by promoting M2 macrophage repolarization.
Area of Science:
- Immunology
- Cell Biology
- Metabolic Research
Background:
- Macrophages are key innate immune cells with diverse activation states (M1/M2).
- Repolarizing M1 macrophages to M2 is a therapeutic target for inflammatory diseases.
- Current understanding of M1-M2 plasticity is incomplete.
Purpose of the Study:
- Investigate the mechanisms preventing M1 macrophage repolarization to M2.
- Identify factors inhibiting M1 to M2 conversion.
- Explore therapeutic strategies to enhance M1-M2 reprogramming.
Main Methods:
- In vitro and in vivo experiments using mouse and human macrophages.
- Analysis of macrophage activation states and metabolic function.
- Intervention targeting nitric oxide production and mitochondrial function.
Main Results:
- M1 macrophages showed limited M1→M2 repolarization upon IL-4 stimulation.
- M2 macrophages were plastic and readily repolarized to M1.
- M1-associated inhibition of mitochondrial oxidative phosphorylation prevents M1→M2 reprogramming.
- Inhibiting nitric oxide production improved mitochondrial function and M2 reprogramming.
Conclusions:
- Inflammatory macrophage activation impairs mitochondrial oxidative phosphorylation, blocking M1→M2 repolarization.
- Targeting mitochondrial function and nitric oxide production can enhance M2 macrophage reprogramming.
- Restoring mitochondrial function presents a potential therapeutic strategy for inflammatory diseases.
More Related Videos
09:40Phosphorus-31 Magnetic Resonance Spectroscopy: A Tool for Measuring In Vivo Mitochondrial Oxidative Phosphorylation Capacity in Human Skeletal Muscle
Published on: January 19, 2017
07:18Author Spotlight: New Insights into PBMC Mitochondrial Responses Using Fluorespirometry
Published on: May 24, 2024
Related Concept Videos
01:45Mitochondrial Membranes
01:38Inflammation