Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder primarily affecting women during the reproductive years, often complicating pregnancy outcomes with elevated levels of neutrophil extracellular traps (NETs) infiltration. However, potential impacts of NETs on placental trophoblasts in SLE and the underlying molecular mechanisms remain unclear. To address this, transcriptome sequencing was conducted on placentas collected from seven pregnant women with SLE and six healthy pregnant controls to identify SLE-specific placental features. The effects of NETs were further assessed in MRL/lpr lupus-prone mice and pristane-induced lupus (PIL) mice, focusing on pregnancy outcomes and placental pathology. In vitro, trophoblasts were stimulated with NETs derived from patients with SLE, followed by molecular analyses such as transcriptomic, cellular energy metabolism assays and liquid chromatography-tandem mass spectrometry to explore the effects and mechanisms of NETs. Results showed elevated NETs were observed in the placentas of both patients with SLE and lupus mouse models, accompanied by activation of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome. Treatment with DNase I significantly improved pregnancy outcomes in MRL/lpr mice, while the use of peptidyl arginine deiminase 4 (PAD4)-deficient mice was beneficial on the pregnancy outcomes of PIL mice. Furthermore, SLE-derived NETs activated pyroptosis in trophoblasts by promoting glycolysis and subsequent lactylation of NLRP3. These findings highlight that NETs contribute to placental damage in SLE by inducing the lactylation of the NLRP3 inflammasome in trophoblasts, demonstrating the therapeutic potential of inhibiting NETs to improve placental function.

Keywords: Lactylation; NLRP3; Neutrophil extracellular traps; Systemic lupus erythematosus; Trophoblast.

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