Figure 3A. Canonical NLRP3 inflammasome activation was not altered by GPx8 deficiency. BMDMs were primed for 6 h with 0.5 μg/ml LPS and then transfected with LPS (TF LPS) for 8 h, stimulated with ATP (5 mM) for 3 h, MSU (150 μg/mL) for 8 h, or nigericin (5 μM) for 3 h. Activation of inflammasome was demonstrated by secreted IL-1β. Data information: data are representative of at least 3 independent experiments and presented as the mean ± SD, n=4-5, technical repeats. P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001 (Student's two‐tailed t‐test).B. GPx8 deficiency enhanced noncanonical inflammasome activation. Activation of the noncanonical inflammasome by different amounts of cytoplasmic LPS was verified by IL-1β (left panel) and LDH release (right panel). Data information: data are representative of at least 3 independent experiments and presented as the mean ± SD, n=4-5, technical repeats. P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001 (Student's two‐tailed t‐test).C. Upregulation of noncanonical inflammasome activation by GPx8 deficiency occurred independently of TLRs. BMDMs were primed for 6 h with 1 μg/ml poly(I:C) and then transfected with LPS for 8 h. Data information: data are representative of at least 3 independent experiments and presented as the mean ± SD, n=4-5, technical repeats. P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001 (Student's two‐tailed t‐test).Over-activation of noncanonical inflammasome induced by GPx8 deficiency in BMDMs can be rescued by ectopically-expressing human GPx8 (hGPx8). (D) Activation of noncanonical inflammasome in BMDMs with empty vector (EV) or hGPx8 was verified by IL-1β (left panel) and LDH release (right panel). Data information: data are representative of at least 3 independent experiments and presented as the mean ± SD, n=4-5, technical repeats. P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001 (Student's two‐tailed t‐test).Over-activation of noncanonical inflammasome induced by GPx8 deficiency in BMDMs can be rescued by ectopically-expressing human GPx8 (hGPx8). (E) Expression of hGPx8 mRNA in BMDMs was confirmed by quantitative reverse transcriptase PCR. Data information: data are representative of at least 3 independent experiments and presented as the mean ± SD, n=4-5, technical repeats.F. GPx8 deficiency enhanced caspase-11 cleavage and activation. Levels of processed caspase-1 and -11 in the supernatants (Sup) and full-length caspase-1, -11 and GAPDH in the cell lysates (Cell ext) were determined by immunoblotting. Fold changes of protein expression were normalized with internal controls and are indicated below the blots.G. RNA expression of caspase-11 was not altered by GPx8 deficiency. Caspase-11 RNA expression of BMDMs isolated from GPx8-/- mice was measured after LPS priming. Data information: ata are representative of at least 3 independent experiments and presented as the mean ± SD, n=4-5, technical repeats.H. GPx8 deficiency enhanced noncanonical inflammasome activation and pyroptosis in vivo. Colon samples from 5 WT or GPx8-/- mice treated with DSS for 5 days were collected on day 7. Levels of full-length and processed caspase-1, -11 and gasdermin D (GSDMD) in tissue lysates were individually analyzed by immunoblots.GPx8-/- mice were more susceptible than WT mice to endotoxic shock by activation of the noncanonical inflammasome. (I) Survival of mice primed with ultra pure LPS (E. coli O55:B5, 400 μg/kg) and re-challenged 6 h later with LPS (40 mg/kg) (n = 8 per group).GPx8-/- mice were more susceptible than WT mice to endotoxic shock by activation of the noncanonical inflammasome. (J) Survival of mice primed with poly(I:C) (LMW 1 mg/kg) and re-challenged 6 h later with LPS (10 mg/kg) (n = 9 per group).GPx8-/- mice were more susceptible than WT mice to endotoxic shock by activation of the noncanonical inflammasome. (K) IL-1β production levels in mice sera were measured 2 h after being primed with poly(I:C) (LMW 1 mg/kg) and re-challenged 6 h later with LPS (1 mg/kg) (n = 8-9 per group). In (K), data are presented as the mean ± SEM. NS, no significance. P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001 (Student's two‐tailed t‐test).