EXO-VNN2 derived from 3D-cultured DPSCs enhances the inflammatory response of PDLSCs and suppresses bone regeneration in periodontitis

Background: As a chronic inflammatory disease characterized by periodontal tissue destruction, periodontitis has a pathogenesis that remains incompletely understood. This study aimed to investigate the expression of upregulated vanin-2 (VNN2) in exosomes derived from dental pulp stem cells (DPSCs) and its effects on the function of periodontal ligament stem cells (PDLSCs) and the progression of periodontitis. Methods: A total of 35 patients with periodontitis and 35 healthy individuals were enrolled for gingival tissue sample collection. DPSC-EXO-VNN2 was cultured with a 3D system and isolated by ultracentrifugation. The samples were then subjected to nanoparticle tracking analysis (NTA), western blot and transmission electron microscopy (TEM). In vitro, PDLSCs were treated with DPSC- EXO-VNN2 and LPS, and the expression of IL-6 and TNF-α and their osteogenic potential were evaluated. Furthermore, in vivo, experimental periodontitis was induced in rats, which were then divided into two groups and treated with either DPSC-EXO-VNN2 or PBS. The maxillae were subsequently collected for histological staining and micro-CT analysis. Results: VNN2 was upregulated in periodontitis according to dataset analysis, western blot and immunofluorescence (P < 0.05). Higher expression levels of VNN2 were associated with greater periodontal parameters PD and CAL (P < 0.05). The production of DPSC-EXO in the 3D culture system surpassed that in the 2D system. In vitro, PDLSCs internalized 3D-DPSC-EXO-VNN2, which increased LPS-induced IL-6 and TNF-α production while reducing osteogenic differentiation, as shown by decreased ALP activity and mineralization. In vivo, DPSC-EXO-VNN2 administration worsened alveolar bone loss, as micro-CT revealed a significantly lower bone volume fraction (P < 0.01) than did the control treatment. Conclusion: This study reveals for the first time that DPSC-EXO-VNN2 participates in the progression of periodontitis by regulating the inflammatory response and osteogenic differentiation ability of PDLSCs. Future research may further explore the potential application of targeting VNN2 in treating periodontitis.