M3 mAChR-mediated IL-8 expression through PKC/NF-κB signaling pathways

Area of Science:

• Pharmacology
• Immunology
• Cell Biology

Background:

• Muscarinic acetylcholine receptors (mAChRs) modulate immune responses.
• The M3 mAChR subtype is implicated in regulating cytokine production during inflammation.

Purpose of the Study:

• To investigate the role of M3 mAChR in interleukin-8 (IL-8) expression upon agonist stimulation.
• To elucidate the signaling pathways involved in M3 mAChR-mediated IL-8 regulation.

Main Methods:

• Utilized recombinant U2OS cells stably expressing M3 mAChR.
• Stimulated cells with carbachol to assess IL-8 mRNA and protein levels.
• Employed specific inhibitors for M3 mAChR, NF-κB, MAP kinases (ERK, p38, JNK), and protein kinase C (PKC).

Main Results:

• Carbachol-induced M3 mAChR activation dose-dependently increased IL-8 expression, blocked by antagonists.
• Inhibition of NF-κB significantly reduced M3 mAChR-mediated IL-8, with partial effects from MAPK inhibitors.
• PKC activation mimicked carbachol's effect on IL-8, and PKC inhibition attenuated M3 mAChR-induced IL-8 and NF-κB activation.

Conclusions:

• M3 mAChR plays a critical role in regulating inflammatory cytokine IL-8.
• The M3 mAChR/PKC/NF-κB signaling axis is a key pathway in inflammatory responses.
• This pathway represents a potential therapeutic target for inflammatory diseases.