Cationic Nanostructures for the Treatment of Inflammatory Bone Loss
Abstract Periodontitis is a common type of inflammatory bone loss and is a risk factor for systemic diseases. The pathogenesis of periodontitis relies on inflammatory dysregulation, which represents a target for new therapeutic strategies to treat periodontitis. Here we demonstrate that cell-free DNA (cfDNA) is correlated with periodontitis in patient samples, and that cfDNA/TLR9 interactions participate in the immune response of periodontitis. We then tested the hypothesis that removing cfDNA would benefit periodontitis treatment. To create nucleic acid-binding nanoparticles (NABNs) specific for periodontitis, we coated bone-mimicking selenium-doped hydroxyapatite nanoparticles with cationic polyamidoamine dendrimers (PAMAM-G3), and compared the activities of these NABNs with those of soluble PAMAM-G3 polymers. Both NABNs and PAMAM-G3 inhibited periodontitis-related inflammation in vitro by scavenging cfDNA, and alleviated inflammatory bone loss in a mouse model of ligature-induced periodontitis. Both cfDNA scavengers also regulated the mononuclear phagocyte system in a periodontitis environment, promoting the M1 over the M2 macrophage phenotype. However, NABNs showed greater therapeutic effects than PAMAM-G3 in terms of scavenging and reducing inflammation and bone loss in vivo. Our findings demonstrate the importance of cfDNA in periodontitis and the potential for using cfDNA-scavenging and hydroxyapatite-based NABNs to ameliorate inflammation and bone loss in periodontitis.