Inflammatory Periodontal Ligament Stem Cells Drive M1 Macrophage Polarization via Exosomal miR-143-3p-Mediated Regulation of PI3K/AKT/NF-κB Signaling.

Macrophage polarization plays an important role in the progression of inflammation. Exosomes derived from stem cells are promising candidates for macrophage immunoregulation. However, how exosomes derived from periodontal ligament stem cells (PDLSCs) in an inflammatory environment influence macrophage polarization has yet to be fully elucidated. In this study, inflammatory PDLSCs were found to downregulate M2 macrophage polarization at the mRNA and protein levels in a Transwell coculture system of PDLSCs and THP-1-derived M0 macrophages. Furthermore, inflammatory PDLSC-derived exosomes shifted macrophages toward the M1 phenotype. The inhibition of inflammatory PDLSC-derived exosomes by GW4869 weakened inflammatory PDLSC-mediated M1 macrophage polarization. A miRNA microarray was used to determine the differential miRNAs shuttled by healthy and inflammatory PDLSC-derived exosomes. Compared with healthy exosomes, miR-143-3p was enriched in inflammatory PDLSC-derived exosomes, which targeted and inhibited the expression of PI3Kγ and promoted M1 macrophage polarization by suppressing PI3K/AKT signaling and activating NF-κB signaling, while an agonist of the PI3K pathway reversed this effect. Moreover, exosome-shuttled miR-143-3p from PDLSCs drove M1 macrophage polarization and aggravated periodontal inflammation in a mouse periodontitis model. In conclusion, these results demonstrate that inflammatory PDLSCs facilitate M1 macrophage polarization through the exosomal miR-143-3p-mediated regulation of PI3K/AKT/NF-κB signaling, providing a potential new target for periodontitis treatment.