Total Glycosides and Regaloside B from Lily: Potential Therapeutic Agents for Osteogenic Differentiation, Migration, and Angiogenesis

Objectives: This study aims to investigate the effects of TGL (total glycosides from lily) and its constituent regaloside B, when absorbed in the blood, on the osteogenic differentiation, migration, and angiogenesis of human umbilical cord-derived mesenchymal stem cells (hUCMSCs).

Methods: hUCMSCs were treated with TNF-α and IFN-γ to induce an inflammatory microenvironment mimicking in vivo conditions. Cell cycle progression and surface markers of the hUCMSCs were analyzed by flow cytometry. Alizarin Red staining was performed to quantify extracellular calcium deposition, reflecting the osteogenic effects of TGL and regaloside B. The relative mRNA and protein expression levels of PTGS1, VEGF, HIF-1α, and CCL5 were assessed by qRT-PCR and Western blotting (WB). Cell migration ability was examined using wound healing assays. TGL components in rat plasma were identified by UHPLC-LTQ-Orbitrap-MSⁿ analysis. The effects of regaloside B on CCL5, CXCL9, CXCL10, VCAM, ICAM, IL8, and IDO mRNA levels were verified under the induction of TNF-α and IFN-γ.

Results: TGL suppressed TNF-α/IFN-γ-induced expression of chemokine CCL5 and angiogenic factors (PTGS1, VEGF), inhibited cell migration, and enhanced osteogenic differentiation of hUCMSCs (p < 0.05). Pharmacokinetic analysis revealed that regaloside B, a systemic metabolite of TGL detected in rat plasma, significantly inhibited TNF-α and IFN-γ-induced chemokines and angiogenic factors in hUCMSCs in comparison with the same dose of TGL (p < 0.05).

Conclusions: TGL and its bioactive metabolite regaloside B demonstrated modulatory effects on TNF-α/IFN-γ-induced alterations in osteogenic differentiation, migratory capacity, and angiogenesis regulatory potential of hUCMSCs, suggesting that regaloside B mediates the therapeutic effects of TGL.