In vitro sepsis up-regulates Nociceptin/Orphanin FQ receptor expression and function on human T- but not B-cells

Area of Science:

• Immunology
• Pharmacology
• Cell Biology

Background:

• Animal models of sepsis show increased Nociceptin/Orphanin FQ (N/OFQ) receptor NOP activation correlates with mortality.
• NOP antagonists have demonstrated improved survival rates in sepsis models.
• The role of the N/OFQ-NOP system in human immune cells during sepsis remains underexplored.

Purpose of the Study:

• To investigate the function of the N/OFQ-NOP system in human B- and T-cells.
• To model sepsis in vitro using lipopolysaccharide (LPS) and peptidoglycan G (PepG) stimulation.
• To determine the impact of N/OFQ-NOP signaling on immune cell migration and cytokine release.

Main Methods:

• Human B- and T-cells were isolated and stimulated with LPS/PepG.
• NOP expression and N/OFQ content were measured using fluorescent probes and immunofluorescence.
• N/OFQ release was assessed via a biosensor assay, and cell migration and cytokine/chemokine release (25-plex) were quantified.

Main Results:

• B-cells constitutively expressed NOP and contained N/OFQ, with release stimulated by CXCL13/IL-4; N/OFQ trended to inhibit migration.
• LPS/PepG increased Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) release in B-cells in an N/OFQ-sensitive manner.
• T-cells showed sepsis-inducible NOP expression upon LPS/PepG treatment, leading to N/OFQ binding that reduced migration and GM-CSF release.

Conclusions:

• A constitutive NOP-mediated autocrine regulation exists in B-cells, while sepsis induces T-cell NOP autocrine regulation.
• NOP receptor activation in both cell types inhibits migration and reduces GM-CSF release.
• These findings elucidate the detrimental role of N/OFQ signaling in sepsis and support NOP antagonists as potential therapeutic agents.