Astragalus Polysaccharide Promotes NLRP3+ Macrophages Polarization via Suppression of OGT in Hepatocellular Carcinoma – Research

Background:

Hepatocellular carcinoma (HCC) is characterized by an immunosuppressive tumor microenvironment (TME) dominated by tumor-associated macrophages (TAMs). Astragalus polysaccharide (APS) exhibits anti-tumor activity, its mechanism in reprogramming immunosuppressive TAMs remains unclear.

Methods:

We established a orthotopic HCC tumor model in C57BL/6 mice and administered APS. Single-cell RNA sequencing (scRNA-seq) was performed to profile immune cell landscapes in HCC TME. Flow cytometry, immunofluorescence, and functional assays were employed to explore the role of O-linked N-acetylglucosamine transferase (OGT) in APS-mediated TME reprogramming.

Results:

APS significantly inhibited tumor growth and remodeled the TME cellular composition. ScRNA-seq revealed 10 cell types in HCC mice tumor tissue. APS increased neutrophils, macrophages, and mast cells while reducing other immune populations. Macrophages were subclassified into C1QC⁺ TAM, NLRP3⁺ TAM, and S100A9⁺ TAM. APS specifically elevated NLRP3⁺ TAM abundance, which positively correlated with M1-like pro-inflammatory phenotypes (TNFα, complement pathway activation). Mechanistically, APS downregulated OGT expression and global O-GlcNAcylation in TAMs, promoting NLRP3⁺ TAM polarization. NLRP3⁺ TAMs with APS treatment secreted pro-inflammatory cytokines and chemokines (IL-6, IL-1B, TNFα, and CXCL10), enhancing CD8⁺ T-cell infiltration and reducing T-cell exhaustion.

Conclusion:

APS suppresses HCC by inhibiting OGT-mediated O-GlcNAcylation and promoting NLRP3⁺ M1-like TAMs enrichment, thereby enhancing anti-tumor immunity, highlighting APS as a potential immunomodulatory agent for HCC therapy.