Moringa oleifera Leaf-Derived Exosome-Like Nanoparticles Target Macrophage Senescence to Drive M2 Polarisation and Attenuate Alveolar Bone Loss

Abstract

Background Periodontitis is a chronic inflammatory disease characterised by progressive alveolar bone loss. Macrophages play a pivotal role in coupling inflammation to disrupted bone metabolism, and their dysregulation is a key driver of bone resorption. However, precise therapeutic modulation of macrophage phenotype and function remains an unmet clinical need. Methods Moringa oleifera leaf-derived exosome-like nanoparticles (MOLELNs) were isolated via ultracentrifugation and subsequently characterised. For the in vitro experiments, an inflammatory model was established by stimulating RAW264.7 cells with lipopolysaccharide (LPS) to induce M1 polarisation. The effects of MOLELNs on macrophage polarisation were initially assessed through ROS detection, flow cytometry, RT-qPCR and Western blot. Transcriptome sequencing (RNA-seq) was then employed to identify differentially expressed genes, followed by KEGG pathway enrichment analysis. The regulatory role of MOLELNs in osteogenic differentiation was further evaluated using a co-culture system of macrophages and periodontal ligament stem cells (PDLSCs). In vivo , a rat model of periodontitis was utilised, and the therapeutic efficacy was evaluated by micro-CT, histological analysis and immunofluorescence staining. Results MOLELNs reduced ROS levels in LPS-stimulated inflammatory macrophages and promoted an M2 phenotype. Further analysis showed that MOLELNs attenuated senescence-associated changes in macrophages and modulated p53-related signalling in vitro . These effects were associated with enhanced M2 polarisation. Macrophage phenotype modulation improved the inflammatory microenvironment and preserved PDLSCs’ osteogenic potential. In vivo, MOLELNs modulated the periodontal macrophage balance toward an M2 phenotype, alleviating alveolar bone loss in the rat periodontitis model. Conclusions This study suggests that MOLELNs alleviate the senescence-associated phenotype of macrophages with involvement of p53 signalling and are associated with enhanced M2 polarisation, contributing to reduced alveolar bone loss in experimental periodontitis. These findings provide mechanistic insight into the immunomodulatory effects of plant-derived nanotherapeutics and offer a preclinical proof-of-concept for their use as a host-modulating adjunctive therapy.