Paeoniflorin suppresses IL-33 production by macrophages

Area of Science:

• Immunology and Pharmacology
• Cytokine Regulation
• Inflammation Research

Background:

• Interleukin-33 (IL-33), a member of the IL-1 cytokine family, plays a significant role in immune responses.
• The regulatory mechanisms of endogenous IL-33 production are not fully understood.
• Paeoniflorin (PF) exhibits known anti-inflammatory and anti-allergy properties.

Purpose of the Study:

• To investigate the effect of Paeoniflorin (PF) on IL-33 production in macrophages.
• To elucidate the underlying molecular mechanisms by which PF regulates IL-33.

Main Methods:

• In vivo studies using enzyme-linked immunosorbent assay (ELISA) to measure IL-33 in LPS-treated mice with PF.
• In vitro assays including MTT, Real-time PCR, ELISA, Calcium imaging, and Western blot on RAW264.7 macrophages.
• Assessment of cytotoxicity, IL-33 expression, Ca2+ influx, Protein Kinase C (PKC), Nuclear Factor-kappa B (NF-κB), and Mitogen-Activated Protein Kinase (MAPK) activation.

Main Results:

• PF significantly reduced TNF-α, IL-1β, and IL-33 production in vivo.
• PF (10 μM) inhibited IL-33 production, Ca2+ influx, PKC activity, NF-κB (p65) activation, and P38MAPK phosphorylation in vitro.
• Inhibitors of NF-κB, P38MAPK, and Ca2+ blockers also reduced LPS-induced IL-33 production.

Conclusions:

• Paeoniflorin suppresses IL-33 production by macrophages.
• The mechanism involves the inhibition of NF-κB and P38MAPK activation.
• Regulation of Ca2+ mobilization is a key component of PF's effect on IL-33 production.