Macrophage Efferocytosis Regulation By Pdlsc-Derived Exosomes In Apical Periodontitis

Our study explores the regulatory effects of exosomes derived from human periodontal ligament stem cells (PDLSCs) on macrophage efferocytosis, aiming to provide new insights into CAP management. Primary PDLSCs were cultured and exposed to Lipopolysaccharide to generate LPS-PDLSCs. Exosomes were isolated and characterized using nanoparticle tracking analysis, transmission electron microscopy, and Western blot. THP-1 cells were differentiated into M0 macrophages and treated with PBS, PDLSC-derived exosomes (NC-EXO), or LPS-PDLSC-derived exosomes (LPS-EXO). Macrophage efferocytosis was evaluated via confocal microscopy and flow cytometry after co-culturing apoptotic neutrophils. Subsequently, western-blot, real-time PCR experiments were conducted to evaluate the secretion of pro- or anti-inflammatory cytokines, including IL-1β, IL-6, and IL-10. Moreover, to elucidate the potential mechanisms of Effero-Exos, Tandem mass tags (TMT)-labeled quantitative proteomics were applied to screen differently expressed proteins for insights into the associated mechanisms. Based on the successful extraction of Effero-Exos, the results revealed NC-EXO significantly enhanced macrophage efferocytosis compared to the PBS group, while LPS-EXO suppressed this process. Moreover, in comparison to the above two groups, macrophages treated with LPS-EXO exhibited increased expression of IL-1β, IL-6, alongside reduced expression of IL-10. The TMT-labeled quantitative proteomics indicated differently expressed proteins between the NC-EXO group and LPS-EXO group. This study underscored the divergent roles of exosomes from healthy and inflamed PDLSCs in modulating macrophage efferocytosis and the progression of chronic apical periodontitis via differently expressed proteins.