Fig. 7: β-TCP stimulation modulated MΦ polarization and exosome production.

A Effect of β-TCP extracts on MΦs polarization. MΦs stimulated by β-TCP extracts for 2 days were Mix-type with upregulated expression of CCR7, CD206, and TGF-β1 and downregulated expression of TNF-α (n = 3, *p < 0.05). B The expression of BMP2, VEGFA, and PDGF-BB was upregulated in β-TCP-stimulated MΦs (n = 3, *p < 0.05). MΦ-Exo production detected by C ExoELISA-ULTRA CD81 assays and D BCA protein assays (n = 3, *p < 0.05). MΦ-Exos induced by β-TCP extracts of 0, 25, 50, and 100 mg/mL for 2 days were referred to as E-0T-2D, E-25T-2D, E-50T-2D, and E-100T-2D, respectively. E Effect of the inhibitor GW4869 on MΦ-exosomal protein secretion (n = 3, *p < 0.05). F Effect of the inhibitor GW4869 on the paracrine effect of β-TCP-stimulated MΦs on BMSCs at Day 3. Gene expression of Runx2, ALP, COL I, OPN, and BMP2 was significantly impaired in the CM-MΦs+β-TCP + GW4869 group compared to the CM- MΦs+β-TCP group (n = 4, *p < 0.05). G Summary of the possible mechanism by which β-TCP regulates the immunomodulation of macrophages and MΦ-Exo-mediated paracrine effects: β-TCP stimulation-induced changes in the cell microenvironment, such as ionic concentrations of Ca²⁺ and PO₄³⁻, which resulted in the increased activity of nSMases to promote BC-Exo production and alter exosomal miRNA cargos. Exosomal miRNAs could contribute to the improved adhesion, proliferation, differentiation, and immunomodulation of tissue cells by signaling pathways, such as the MAPK and NFκB pathways.