Effect of Human Periodontal Ligament Stem Cell-Derived Extracellular Vesicles on Macrophage Pyroptosis and Periodontal Inflammatory Injury in Periodontitis

Periodontitis is an inflammatory disease resulting from subgingival microorganisms. Human periodontal ligament stem cells (hPDLSCs) can be applied in periodontal tissue regeneration. This study investigated the effect of hPDLSC-derived extracellular vesicles (EVs) on periodontitis. hPDLSC-derived EVs were isolated and identified. The murine model of periodontitis was established by ligation, and the cell model of periodontitis was established by treatment of macrophages with lipopolysaccharide (LPS). The effects of EVs on macrophage pyroptosis and periodontal inflammatory injury were measured by the means of HE staining, detection of LDH content, CCK-8 assay, Calcein-AM/PI staining, ELISA, Western blot, as well as measurement of caspase-1, SOD, and MDA. miR-590-3p expression was detected using RT-qPCR. miR-590-3p expression was then intervened to validate the effect of miR-590-3p on macrophage pyroptosis. The binding relationship between miR-590-3p and TLR4 was verified using dual-luciferase assay. Functional rescue experiment was performed to validate the role of TLR4 in macrophage pyroptosis. The results showed that inflammatory levels and macrophage pyroptosis were enhanced in the in vivo and in vitro models of periodontitis, evidenced by the increased NLRP3, GSDMD-N, caspase-1, IL-1β, IL-18, TNF-α, and MDA and decreased IL-10 and SOD. EVs alleviated periodontal inflammatory injury and macrophage pyroptosis. Physiologically, EVs carried miR-590-3p into macrophages to upregulate miR-590-3p expression and thereby suppress TLR4 transcription. miR-590-3p silencing or TLR4 overexpression reduced the inhibitory effect of EVs on macrophage pyroptosis. Collectively, EVs carried miR-590-3p into macrophages to subsequently inhibit TLR4 transcription, thereby reducing macrophage pyroptosis and alleviating periodontal inflammatory injury.