IWP‐2 modulates the immunomodulatory properties of human dental pulp stem cells in vitro

Aim To investigate the effect of IWP‐2, Wnt inhibitor, on human dental pulp stem cells (hDPSCs) responses. Methodology hDPSCs were isolated from human dental pulp tissues. Cells were treated with 25 μM IWP‐2 for 24 h, and subsequently, the gene expression profile was examined using high‐throughput RNA sequencing. The mRNA expression was analysed using qPCR. The effect of IWP‐2 was investigated in both normal and LPS‐induced hDPSCs (inflamed hDPSCs). CD4+ T cells and CD14+ monocyte‐derived macrophages were cultured with conditioned media of IWP‐2 treated hDPSCs to observe the immunosuppressive property. Results RNA sequencing indicated that IWP‐2 significantly downregulated several KEGG pathways, including cytokine‐cytokine receptor interaction, IL‐17 signalling pathway, and TNF signalling pathway. In both normal and inflamed conditions, IWP‐2 markedly upregulated TGFB1 mRNA expression while the mRNA expression of pro‐inflammatory cytokines, TNFA, IL1B, IFNG, and IL6, was inhibited. In the inhibition experiment, the pretreatment with p38, MAPK, or PI3K inhibitors abolished the effects of IWP‐2 in LPS‐induced inflammation. In terms of immune cells, IWP‐2‐treated‐inflamed hDPSCs conditioned media attenuated T cell proliferation and regulated regulatory T cell differentiation. In addition, the migratory property of macrophage was decreased after being exposed to IWP‐2‐treated inflamed hDPSCs conditioned media. Conclusion IWP‐2 suppressed inflammatory cytokine expression in both normal and inflamed hDPSCs. Moreover, hDPSCs exerted the immunosuppressive property after IWP‐2 treatment. These results suggest the role of Wnt in inflammatory responses and immunomodulation in dental pulp tissues.