The Sesn2/Nrf2 axis suppresses oxidative stress and pyroptosis-associated signaling in LPS/nigericin-challenged alveolar macrophages.

BACKGROUND: Pyroptosis is a key mechanism driving immune imbalance in sepsis, while the stress-induced protein Sestrin 2 (Sesn2) and Nuclear factor E2-related factor 2 (Nrf2) are core regulators of antioxidant defense. No existing studies have clarified the interactive regulatory effect of the Sesn2/Nrf2 axis on pyroptosis in alveolar macrophages. Therefore, this study aims to investigate the regulatory mechanism of the Sesn2/Nrf2 axis on pyroptosis and oxidative stress in LPS/nigericin-challenged alveolar macrophages, providing a theoretical basis for further understanding of sepsis. METHODS: Bioinformatics analysis involved screening differentially expressed genes in sepsis from the Gene Expression Omnibus dataset GSE185263, intersecting them with genes related to pyroptosis and ferroptosis, constructing a protein-protein interaction network, and identifying core genes. An inflammatory injury model was established in the mouse alveolar macrophage cell line MH-S by stimulating cells with LPS and nigericin. Interventions were performed using siRNA to knock down Sesn2 and plasmids to overexpress Nrf2. Cell viability, oxidative stress markers, expression of pyroptosis-related molecules, and secretion of inflammatory cytokines were measured. RESULTS: SESN2 as a key gene common to sepsis, pyroptosis, and ferroptosis. The Sesn2/Nrf2 signaling axis significantly enhanced the cell viability of MH-S cells after inflammatory injury, increased Superoxide Dismutase activity and Glutathione levels, and reduced reactive oxygen species and Lactate Dehydrogenase levels. Simultaneously, this axis suppressed the expression of pyroptosis-related inflammasomes (NOD-like receptor thermal protein domain associated protein 3, Absent in melanoma 2) and key execution proteins (Gasdermin D, Cleaved Caspase-1, Caspase-4), and reduced the secretion of inflammatory cytokines IL-1β, IL-18, and TNF-α. Sesn2 and Nrf2 exhibited mutual positive regulation in macrophages following inflammatory injury. CONCLUSION: In vitro cell model studies indicate that the Sesn2/Nrf2 axis synergistically suppresses oxidative stress and pyroptosis-associated signaling in LPS/nigericin-challenged alveolar macrophages, suggesting that this axis may represent a potential target warranting further investigation in in vivo models.