Modulation Of Osteogenesis By Salivary Exosomes In Periodontal Microenvironment

Salivary exosomes (Salivary-Exo) serve as an important reservoir of biomarkers that may reflect the status of periodontal disease, however, the relationship between severe periodontitis-induced alveolar bone resorption and the morphology and function of Salivary-Exo in this context, along with the specific underlying mechanisms, remains unclear. Salivary-Exo from patients with severe periodontitis (SSP-Exo) and healthy receptors (SH-Exo) were isolated by ultracentrifugation and characterized by transmission electron microscopy (TEM), nanoparticle tracer analysis (NTA) and Western Blot. In vitro, periodontal ligament stem cells (PDLSCs) were treated with SSP-Exo and SH-Exo, the abilities of cell proliferation, migration and osteogenic potential were evaluated. Furthermore, transcriptomic profiling was conducted through targeted gene silencing, overexpression assays and qRT-PCR. In vivo, an alveolar bone defect model in rabbit was established and treated with SSP-Exo and SH-Exo. The mandibles were collected at 4, 8, and 12 weeks, respectively, and examined by micro-CT and histological staining. SSP-Exo inhibited the proliferation, migration and osteogenesis of PDLSCs while promoting the apoptosis of PDLSCs in vitro. In addition, the results showed that SSP-Exo downregulated the expression of osteogenic gene. In vivo, we found that SH-Exo demonstrated significant in situ osteogenic capacity in rabbits with alveolar bone defects. Salivary-Exo plays an important role in regulating the osteogenic differentiation of PDLSCs in the microenvironment of periodontitis. This study suggests a promising exosome-based therapy for periodontitis.