Cd169+ Macrophages In Periodontitis: A New Target For Therapy

This study is to investigates the functions of a unique type of macrophages, CD169+ macrophages, during periodontitis and the recovery phase of periodontitis. Periodontal tissues were analyzed by immunohistochemical staining (IHC), which were collected from periodontitis patients and healthy individuals. CD169+ macrophages were isolated from mouse bone marrow-derived macrophages (BMDMs) using magnetic bead sorting and analyzed by qPCR, flow cytometry, and indirect co-culture with bone marrow mesenchymal stem cells (BMSCs) experiments. In vivo, experiments were performed using a ligature-induced periodontitis (LIP) mouse model, besides Micro-CT, immunofluorescence and IHC were used to explain the effects of blocking IFNIAR1 in the animal models. The number of CD169+ macrophages in the gingival tissues of periodontitis patients was higher than that in the healthy control group. In vitro experiments showed that CD169+ macrophages had stronger ability of phagocytosis, anti-inflammatory phenotype and could promote osteogenesis. We also proved that IFNα can induce the differentiation of macrophages into CD169+ macrophages. In vivo experiments further indicated that blocking the type I interferon pathway would inhibit the increase of CD169+ macrophages. This leads to more severe bone loss and impaired restoration of bone resorption. This study reveals the important roles of CD169+ macrophages in periodontitis. Their differentiation is regulated by the type I interferon pathway. These cells demonstrate enhanced phagocytic and osteogenic capabilities.