Objective To investigate the effects of wedelolactone (WEL) on lipopolysaccharide (LPS)-induced pyroptosis of alveolar epithelial cells and AMP-activated protein kinase/nucleotide binding oligomeric domain like receptor 3 (NLRP3)/cysteinyl aspartate specific proteinase-1 (Caspase-1) signaling pathway. Methods Human lung epithelial cells BEAS-2B were treated with 5 - 200 μmol/L wedelolactone, and cell activity was detected using MTT assay. The alveolar epithelial cells were divided into control group, lipopolysaccharide group (LPS group), 10 μmol/L wedelolactone group (WEL-L group), 20 μmol/L wedelolactone group (WEL-M group), 40 μmol/L wedelolactone group (WEL-H group), 40 μmol/L wedelolactone+10 μmol/L AMPK inhibitor Compound C group (WEL-H+Compound C group), and 20 μmol/L Caspase-1 inhibitor Z-YVAD-FMK group (Z-YVAD-FMK group). Transmission electron microscopy was applied to observe the microstructure of cells. ELISA was applied to detect levels of inflammatory factors such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-8 (IL-8). Immunofluorescence was applied to detect Caspase-1 and gasdermin family proteins (DGSDMD). Western blot was applied to detect protein expression levels of AMPK, NLRP3, and Caspase-1. Results Wedelolactone concentrations of 10, 20 and 40 μmol/L were selected for follow-up experiments. Compared with Control group, LPS group showed decreased cell activity, severe damage, cell contraction, mitochondrial ridge breakage and decreased number, increased levels of TNF-α, IL-1β, IL-8 and GSDMD, NLRP3, Caspase-1 expression, and decreased p-AMPK/AMPK expression (P<0.05). Wedelolactone treatment could significantly improve LPS-induced pyrosis of alveolar epithelial cells (P<0.05). Compound C could partially reverse the effect of wedelactone on LPS-induced pyrodeath of alveolar epithelial cells (P<0.05). Z-YVAD-FMK treatment also significantly improved LPS-induced pyroptosis of alveolar epithelial cells (P<0.05). Conclusion Wedelolactone can inhibit LPS-induced pyroptosis of pulmonary alveolar epithelial cells by inhibiting AMPK/NLRP3/Caspase-1 signaling pathway.
Objective To investigate the effect of picroside Ⅱ (PIC Ⅱ) on the pyroptosis and thioredoxin-interacting protein (TXNIP)/nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) signaling pathway in alveolar epithelial cells of severe pneumonia rats. Methods A severe pneumonia rat model was constructed and all experimental rats were divided into a control group, a severe pneumonia group, low, medium, and high dose PIC Ⅱ groups (PIC Ⅱ-L, PIC Ⅱ-M, PIC Ⅱ-H groups), and a high-dose PIC Ⅱ+TXNIP/NLRP3 pathway activator trimethylamine oxide group (PIC Ⅱ-H+TMAO group). The levels of tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were detected by ELISA; Wright’s staining was applied to detect eosinophil count (EOS), lymphocyte count (LYM), and neutrophil count (NEU) in the sediment of alveolar lavage fluid. Hematoxylin-eosin staining was used to observe the pathological changes of lung tissue. The expressions of cysteine aspartate protease 1 (Caspase-1) and dermatin D (GSDMD) were detected by immunohistochemistry. The expressions of TXNIP, NLRP3 and apoptosis-associated microprotein (ASC) were detected by Western blot. Results Compared with the control group, the severe pneumonia group had severe lung tissue injury, obvious inflammatory cell infiltration, and increased expressions of TNF-α, IL-1β, IL-6, EOS, LYM, NEU, Caspase-1, GSDMD, TXNIP, NLRP3 and ASC (all P<0.05). Compared with the severe pneumonia group, lung tissue injury in PIC Ⅱ-L, PIC Ⅱ-M and PIC Ⅱ-H groups was reduced successively, and inflammatory cell infiltration was gradually reduced. The expressions of TNF-α, IL-1β, IL-6, EOS, LYM, NEU, Caspase-1, GSDMD, TXNIP, NLRP3 and ASC were decreased successively (all P<0.05). Compared with the PIC Ⅱ-H group, the PIC Ⅱ-H+TMAO group showed increased lung tissue damage and obviously increased inflammatory cell infiltration, the expression of TNF-α, IL-1β, IL-6, EOS, LYM, NEU, Caspase-1, GSDMD, TXNIP, NLRP3, and ASC were obviously increased (all P<0.05). Conclusion PIC Ⅱ inhibits pyroptosis of alveolar epithelial cells in severe pneumonia rats by inhibiting the TXNIP/NLRP3 pathway.