Bacterial infection caused cell pyroptosis and gingival inflammation contributes to periodontitis progression, and lipopolysaccharide (LPS) is the main infectious agent of gram-negative bacteria, which is reported to be closely associated with gingival inflammation and periodontitis. In this study, the primary human periodontal ligament cells (PDLCs) were isolated, cultured, and exposed to LPS treatment, and the results suggested that LPS suppressed cell viability and promoted pro-inflammatory cytokines’ (IL-1β, IL-18, IL-6, and TNF-α) generation and secretion in the PDLCs and its supernatants in a time- and concentration-dependent manner. Also, we noticed that LPS upregulated NLRP3, Gasdermin D, and cleaved caspase-1 to trigger pyroptotic cell death in the PDLCs. Further experiments identified that glycogen synthase kinase-3β (GSK-3β) was upregulated by LPS treatment, and inhibition of GSK-3β by its inhibitor (GSKI) or GSK-3β downregulation vectors was effective to restore normal cellular functions in LPS-treated PDLCs. Mechanistically, blockage of GSK-3β restrained NLRP3-meidated cell pyroptosis and inflammation, resulting in the recovery of cell viability and inhibition of cell death in PDLCs treated with LPS, which further ameliorated periodontitis progression. Finally, we collected the serum from periodontitis patients and healthy volunteers, and the clinical data supported that those pro-inflammatory cytokines were also upregulated in patients’ serum but not in the healthy participants. Taken together, we concluded that targeting the GSK-3β/NLRP3 pathway mediated cell pyroptosis was effective to attenuate LPS-induced cell death and inflammation in PDLCs, and this study firstly investigated this issue, which broadened our knowledge in this field.

细菌感染引起的细胞焦亡和牙龈炎症有助于牙周炎的进展，脂多糖（LPS）是革兰氏阴性菌的主要感染因子，据报道与牙龈炎症和牙周炎密切相关。在这项研究中，原代人牙周膜细胞 (PDLCs) 被分离、培养并暴露于 LPS 处理，结果表明 LPS 抑制细胞活力并促进促炎细胞因子（IL-1β、IL-18、IL -6 和 TNF-α) 在 PDLCs 及其上清液中以时间和浓度依赖性方式产生和分泌。此外，我们注意到 LPS 上调 NLRP3、Gasdermin D 和裂解 caspase-1 以触发 PDLC 中的细胞焦亡。进一步的实验确定糖原合酶激酶-3β (GSK-3β) 被 LPS 处理上调，其抑制剂 (GSKI) 或 GS​​K-3β 下调载体抑制 GSK-3β 可有效恢复 LPS 处理的 PDLC 的正常细胞功能. 从机制上讲，GSK-3β 的阻断抑制了 NLRP3 介导的细胞焦亡和炎症，导致用 LPS 处理的 PDLC 中细胞活力的恢复和细胞死亡的抑制，这进一步改善了牙周炎的进展。最后，我们收集了牙周炎患者和健康志愿者的血清，临床数据支持这些促炎细胞因子在患者血清中也上调，但在健康参与者中没有上调。综合起来，