Regulation of macrophage activation by proteins expressed on apoptotic neutrophils: Subversion towards autoimmunity...

Area of Science:

• Immunology
• Molecular Biology
• Inflammation Research

Background:

• Neutrophils are key players in host defense and inflammation modulation.
• Resolution of inflammation requires a complex molecular dialogue between apoptotic neutrophils and proresolving macrophages.
• Efficient efferocytosis and anti-inflammatory reprogramming are critical for immune regulation.

Purpose of the Study:

• To review molecular mechanisms governing the resolution of inflammation involving apoptotic neutrophils.
• To highlight the roles of specific proteins on apoptotic neutrophils and their macrophage receptors.
• To examine how proteinase 3 (PR3) on apoptotic neutrophils influences efferocytosis and immune responses.

Main Methods:

• Review of recent molecular analyses on proteins expressed by apoptotic neutrophils.
• Analysis of cognate partners expressed on macrophages involved in inflammation resolution.
• Examination of chemokine receptors, ligands, annexin A1, its receptor FPR2, and proteinase 3 (PR3).

Main Results:

• Proteins on apoptotic neutrophils, including chemokine receptors and annexin A1, mediate interactions with macrophages.
• Proteinase 3 (PR3), an autoantigen in vasculitis, is expressed on apoptotic neutrophils and affects efferocytosis.
• The fate of apoptotic neutrophils directly influences inflammation resolution and immune responses.

Conclusions:

• Molecular interactions between apoptotic neutrophils and macrophages are central to resolving inflammation.
• Dysfunctional efferocytosis of apoptotic neutrophils, influenced by proteins like PR3, can lead to nonresolving inflammation and autoimmunity.
• Understanding these interactions is vital for developing strategies to manage inflammatory diseases and autoimmunity.