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Updated: Jun 25, 2025
In Vivo Assessment of Alveolar Macrophage Efferocytosis Following Ozone Exposure
Published on: October 22, 2019
[Strong as death or how efferocytotic macrophages promote the resolution of inflammation]
Mathieu Vetter1, Philippe Saas2
1Université de Franche-Comté, Établissement Français du Sang (EFS), Inserm, UMR 1098 RIGHT Besançon, France - LabEx LipSTIC, Besançon, France.
Abstract:
The resolution of inflammation is an active process leading to the restoration of tissue homeostasis. A critical step in the initiation of this process is the elimination of apoptotic immune cells by macrophages. This well-organized process, called efferocytosis, involves four different steps, namely the attraction of macrophages to the site where the cells die, the recognition of apoptotic cells, their internalization and their digestion leading to the activation of different metabolic pathways. All these steps are responsible for the reprogramming of macrophages towards a pro-resolving profile. Efferocytic macrophages produce several factors involved in the resolution of inflammation. These factors include lipids (i.e., specialized pro-resolving mediators such as lipoxins), and proteins (e.g., IL-10 or TGF-β). Here, we describe the different steps of efferocytosis and the mechanisms responsible for both macrophage reprogramming and the release of pro-resolving factors. These factors may represent a new therapeutic approach, called resolution therapy.
Insights
The resolution of inflammation involves macrophages clearing dead cells through efferocytosis. This process reprograms macrophages to release factors that actively restore tissue balance, paving the way for new therapies.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Inflammation resolution is crucial for tissue homeostasis.
- Macrophage-mediated clearance of apoptotic cells (efferocytosis) is a key initiating step.
- Efferocytosis involves distinct stages: attraction, recognition, internalization, and digestion.
Purpose of the Study:
- To elucidate the mechanisms of efferocytosis.
- To describe macrophage reprogramming during efferocytosis.
- To identify pro-resolving factors released by efferocytic macrophages.
Main Methods:
- Review of cellular and molecular mechanisms of efferocytosis.
- Analysis of metabolic pathways activated in macrophages.
- Identification of lipid and protein mediators involved in inflammation resolution.
Main Results:
- Efferocytosis reprograms macrophages to a pro-resolving phenotype.
- Activated macrophages release specialized pro-resolving mediators (SPMs) like lipoxins.
- Pro-resolving proteins such as IL-10 and TGF-β are also produced.
Conclusions:
- Efferocytosis is a complex, multi-step process essential for inflammation resolution.
- Macrophage reprogramming during efferocytosis drives the production of critical pro-resolving factors.
- These factors hold potential for developing novel 'resolution therapies'.
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