Signaling Through Purinergic Receptor P2Y₂ Enhances Macrophage IL-1β Production

Area of Science:

• Immunology
• Cell Biology
• Molecular Biology

Background:

• Nucleotide release during cell death can exert dual pro- and anti-inflammatory effects.
• Macrophages play a central role in orchestrating inflammatory responses.

Purpose of the Study:

• To investigate the specific effects of extracellular nucleotides on macrophage inflammatory cytokine production.
• To elucidate the role of the P2Y2 receptor in nucleotide-mediated macrophage activation.

Main Methods:

• Murine resident peritoneal macrophages were primed with low concentrations of UTP and ATP.
• Subsequent activation of the NLRP3 inflammasome was performed.
• Interleukin-1 beta (IL-1β) and Tumor Necrosis Factor-alpha (TNF-α) production were measured.
• The role of the P2Y2 receptor was assessed using genetic deficiency and pharmacological inhibition.
• Gene expression of Il1b and JNK activity were analyzed.

Main Results:

• Priming macrophages with low UTP/ATP concentrations significantly enhanced IL-1β production upon NLRP3 inflammasome activation.
• This enhancement was dependent on the P2Y2 purinergic receptor and Il1b gene expression, likely involving JNK signaling.
• Conversely, nucleotides suppressed the production of other pro-inflammatory cytokines, such as TNF-α.
• Nucleotides thus induce a specific pro-inflammatory profile in macrophages.

Conclusions:

• Extracellular nucleotides, specifically UTP and ATP, can selectively modulate macrophage inflammatory responses.
• The P2Y2 receptor is critical for nucleotide-induced enhancement of IL-1β production.
• These findings suggest a mechanism by which nucleotides shape macrophage inflammatory signatures, potentially relevant to specific inflammatory diseases.