Rheumatoid arthritis (RA) is an enduring, progressive autoimmune disorder. Abnormal activation of fibroblast-like synoviocytes (FLSs) has been proposed as the initiating factor for inflammation of the synovium and bone destruction. Neutrophil extracellular traps (NETs), which are web-like structures composed of DNA, histones, and granule proteins, are involved in the development of RA in multiple aspects. Pyroptosis, gasdermin-mediated inflammatory programmed cell death, plays a vital function in the etiopathogenesis of RA. However, the exact mechanism underlying NETs-induced pyroptosis in FLSs of RA and its impact on cellular pathogenic behavior remain undefined. In this study, we demonstrated that gasdermin E (GSDME) expression was upregulated in RA plasma and synoviums, which was positively correlated with the elevated cell-free DNA (cfDNA) and citrullinated histone 3 (Cit H3) levels in the plasma. Additionally, in vitro experiments have shown that NETs triggered caspase 3/GSDME-mediated pyroptosis in RA-FLSs, characterized by decreased cell viability, cell membrane blebbing, and rupture, as well as increased levels of pyroptosis-related proteins and pro-inflammatory cytokines. Again, silencing GSDME significantly inhibited pyroptosis and suppressed the migration, invasion, and secretion of pro-inflammatory cytokines in RA-FLSs. Furthermore, we also found that the nuclear factor-kappa B (NF-κB) pathway, serving as an upstream mechanism, was involved in FLS pyroptosis. In conclusion, our investigation indicated that NETs could induce RA-FLS pyroptosis and facilitate phenotypic transformation through targeting the NF-κB/caspase 3/GSDME axis. This is the first to explore the crucial role of NETs-induced FLS pyroptosis in the progression of RA, providing novel targets for the clinical management of refractory RA.

类风湿关节炎（RA）是一种持久的、进行性的自身免疫性疾病。成纤维样滑膜细胞（FLS）的异常激活已被认为是滑膜炎症和骨质破坏的起始因素。中性粒细胞胞外陷阱（NET）是由DNA、组蛋白和颗粒蛋白组成的网状结构，在多个方面参与RA的发生。细胞焦亡（gasdermin 介导的炎症性程序性细胞死亡）在 RA 的发病机制中发挥着重要作用。然而，NETs 诱导 RA FLS 细胞焦亡的确切机制及其对细胞致病行为的影响仍不清楚。在这项研究中，我们证明了 RA 血浆和滑膜中 Gasdermin E (GSDME) 表达上调，这与血浆中游离 DNA (cfDNA) 和瓜氨酸组蛋白 3 (Cit H3) 水平升高呈正相关。此外，体外实验表明，NETs 在 RA-FLS 中触发 caspase 3/GSDME 介导的焦亡，其特征是细胞活力降低、细胞膜起泡和破裂，以及焦亡相关蛋白和促炎细胞因子水平增加。同样，沉默 GSDME 可显着抑制细胞焦亡，并抑制 RA-FLS 中促炎细胞因子的迁移、侵袭和分泌。此外，我们还发现核因子-κB（NF-κB）通路作为上游机制参与FLS焦亡。总之，我们的研究表明 NET 可以通过靶向 NF-κB/caspase 3/GSDME 轴诱导 RA-FLS 焦亡并促进表型转化。这是首次探讨 NETs 诱导的 FLS 焦亡在 RA 进展中的关键作用，为难治性 RA 的临床治疗提供新的靶点。