The antiangiogenic effect of total saponins of Panax japonicus C.A. Meyer in rheumatoid arthritis is mediated by targeting the HIF-1α/VEGF/ANG-1 axis

Abstract

Ethnopharmacological relevance: Traditional Chinese herbal medicine Panax japonicus C.A. Meyer has a long history in clinical treatment of rheumatoid arthritis (RA). Total saponins of Panax japonicus C.A. Meyer (TSPJs) were extracted from the root of Panax japonicus C.A. Meyer, and its anti-rheumatism mechanism is still unclear.

Aim of the study: To investigate whether TSPJs attenuated synovial angiogenesis in RA and explore the potential mechanisms.

Materials and methods: Potential TSPJs targets involving gene function were predicted by network pharmacology related databases. Bioinformatics analysis and molecular docking technology were used to predict the mechanism of TSPJs in the treatment of RA. The predicted results were validated by cell experiments and a collagen-induced arthritis (CIA) mouse model.

Results: Bioinformatics analysis results showed that TSPJs may inhibit RA-related angiogenesis through the hypoxia-inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) pathways. In vitro, different doses of TSPJs showed a good inhibitory effect on the tube formation of EA.hy926 cells. The results of the cellular thermal shift assay indicated that TSPJs can bind to the HIF-1α, VEGFA, and angiopoietin-1 (ANG-1) proteins. In vivo, the administration of TSPJs alleviated the symptoms of CIA mice, including the arthritis index, hind paw thickness, and swollen joint count. The histological results demonstrated that TSPJs inhibited inflammation, angiogenesis, bone damage, and cartilage destruction. Furthermore, TSPJs decreased the number of vessels and the expression level of CD31. The mechanistic results revealed that TSPJs decreased the expression of HIF-1α, VEGFA, and ANG-1 in the serum or synovial tissues of CIA mice.

Conclusion: These results suggest that TSPJs effectively inhibit angiogenesis in RA, and the mechanism may be related to inhibiting the HIF-1α/VEGF/ANG-1 axis.

Keywords: Angiogenesis; Collagen-induced arthritis; Panax japonicus C.A. Meyer; Rheumatoid arthritis; Saponins.