Mannose Receptor Mediates the Immune Response to Ganoderma atrum Polysaccharides in Macrophages

Area of Science:

• Immunology
• Molecular Biology
• Pharmacology

Background:

• Mannose receptor (MR) is known for recognizing carbohydrate structures.
• Ganoderma atrum polysaccharide (PSG-1) is a compound with potential immunomodulatory effects.
• Understanding the interaction between polysaccharides and immune receptors is crucial for developing novel therapeutics.

Purpose of the Study:

• To investigate the role of Mannose Receptor (MR) in the immune response to Ganoderma atrum polysaccharide (PSG-1).
• To elucidate the signaling pathways involved in PSG-1-mediated immune modulation.
• To explore the interplay between MR and Toll-like Receptor 4 (TLR4) in macrophage activation.

Main Methods:

• Macrophage cultures were treated with PSG-1.
• Expression levels of MR, IL-1β, TNF-α, and IL-10 were measured.
• Phagocytosis assays were performed.
• The effect of anti-MR antibody on PSG-1-mediated responses was assessed.
• Nuclear factor-kappa B (NF-κB) pathway activation was analyzed in LPS-stimulated macrophages treated with PSG-1.

Main Results:

• PSG-1 increased MR expression, phagocytosis, IL-1β, and TNF-α in normal macrophages.
• PSG-1 elevated IL-10 and inhibited phagocytosis and IL-1β in LPS-stimulated macrophages, indicating anti-inflammatory effects.
• Anti-MR antibody partially blocked PSG-1's anti-inflammatory effects, suggesting involvement of other receptors.
• MR and TLR4 coordinated to influence the TLR4-mediated NF-κB signaling pathway in response to PSG-1.

Conclusions:

• Macrophage recognition of PSG-1 via MR is essential for initiating immune responses.
• The NF-κB pathway is central to the coordinated action of MR and TLR4 in PSG-1-induced immunity.
• PSG-1 exhibits dual immunomodulatory effects, acting as both an immune activator and an anti-inflammatory agent depending on the context.