Journal: Advanced Science

Article Title: Membrane‐Active Peptide Protects Against Inflammation by Targeting NLRP3 Activation at the Trans‐Golgi Network

doi: 10.1002/advs.76587

Figure Lengend Snippet: Pre‐incubation with Pep19‐2.5 inhibits nigericin‐ and MSU crystal‐induced IL‐1β secretion. (A) Primary monocytes were primed with 1 µg/mL Pam 3 CSK 4 for 3 h and then stimulated with 10 µM nigericin or 200 µg/mL MSU crystals for 3 h. Pep19‐2.5 was added 30 min before priming at increasing concentrations ranging from 0.4 to 18 µM. Supernatants were analyzed for IL‐1β by ELISA. Stimulus‐induced IL‐1β secretion was set to 100%. Mean ± SEM ( n = 4 biologically independent experiments for nigericin, n = 2 biologically independent experiments for MSU crystals). One‐sample t ‐test against 100%. (B) hMDMs were primed with 1 µg/mL Pam 3 CSK 4 for 4 h and then stimulated with 5 µM nigericin for 2 h. Pep19‐2.5 was added at the indicated concentrations 30 min before priming. Supernatants were analyzed for IL‐1β by ELISA. Stimuli‐induced IL‐1β secretion was set to 100%. Mean + SEM ( n = 4 biologically independent experiments). One‐sample t ‐test against 100%. (C) THP‐1 macrophages were primed and stimulated as described in (A). For inhibition experiments, 18 µM Pep19‐2.5 was added 30 min before priming. Supernatants were analyzed for IL‐1β by ELISA. Stimulus‐induced IL‐1β secretion was set to 100%. Mean + SEM ( n = 4 biologically independent experiments for nigericin, n = 3 biologically independent experiments for MSU crystals). One‐sample t ‐test against 100%. (D and E) THP‐1 macrophages were primed and treated with NLRP1 (D) or AIM2 (E) activators. Supernatants were analyzed for IL‐1β by ELISA. Stimulus‐induced IL‐1β secretion was set to 100%. Mean + SEM ( n = 3 biologically independent experiments). One‐sample t ‐test against 100%. (F–H) Protein expression of pro‐IL‐1β (F), full‐length (G), and cleaved GSDMD (H) were analyzed by Western blot. Basal, Pam 3 CSK 4 ‐ or nigericin‐induced expression was set to 100%. Mean + SEM ( n = 3 biologically independent experiments). One‐sample t ‐test against 100%. (I) THP‐1 macrophages were primed and stimulated after peptide incubation as described in (A). After 1 h of stimulation with nigericin, the medium was removed, and Z‐WEHD buffer was added according to the manufacturer´s protocol. Ac‐YVAD‐CHO control was subtracted, and stimulus‐induced caspase‐1 activity was normalized to 100%. Mean ± SEM ( n = 3 biologically independent experiments). One‐sample t ‐test against 100%. (J) hMDMs from healthy donors were seeded in µ‐Slides VI and incubated at 37°C in a humidified atmosphere of 5% CO 2 for 1 h. Macrophages were primed with 1 µg/mL Pam 3 CSK 4 for 3 h and stimulated with 10 µM nigericin for 1 h in the presence of fluorophore‐conjugated Rh‐Pep19‐2.5. Active caspase‐1 was stained with the caspase‐1 pseudosubstrate FLICA660‐YVAD‐FMK. Cells were washed and fixed, and nuclei were stained with Hoechst 34580. Confocal microscopy images are representative of n = 2 biologically independent experiments. Scale bar is 10 µm (upper panel) and 2 µm (zoomed in lower panel). (K) Solutions containing 0.5 µM Atto488‐conjugated Pep19‐2.5 were prepared in the presence of increasing concentrations of recombinant human caspase‐1 and incubated overnight at 4°C under gentle agitation. Microfluidic diffusional sizing (MDS) measurements were performed at room temperature to determine the hydrodynamic radius ( R h ) of fluorescently labeled particles. Dots represent the mean ± SD of replicates ( n ≥ 3) of free peptide and peptide–protein complexes, and the black line represents the best nonlinear fit according to Equation . (L) Human recombinant caspase‐1 was incubated with the caspase‐1‐specific substrate Ac‐YVAD‐AMC at the indicated concentrations of Pep19‐2.5 or 40 µM of the caspase‐1 inhibitor VX765. Enzyme activity in relative fluorescence units (RFU) was measured every 2 min at 37°C. Representative traces are means ± SEM ( n = 2 biologically independent experiments).

Article Snippet: The fluorogenic caspase‐1 substrate Ac‐YVAD‐AMC (HY‐P2717, MedChemExpress, NJ, USA) was added to a final concentration of 10 μM.

Techniques: Incubation, Enzyme-linked Immunosorbent Assay, Inhibition, Expressing, Western Blot, Control, Activity Assay, Staining, Confocal Microscopy, Recombinant, Gentle, Labeling, Fluorescence

Journal: Advanced Science

Article Title: Membrane‐Active Peptide Protects Against Inflammation by Targeting NLRP3 Activation at the Trans‐Golgi Network

doi: 10.1002/advs.76587

Figure Lengend Snippet: Pep19‐2.5 reduces pro‐inflammatory IL‐1β response to house dust mite extract in vitro and in vivo. (A–E) Human macrophages from heathy donors were seeded in serum‐free Opti‐MEM medium and stimulated without priming with the indicated doses of house dust mite (HDM) extract for 24 h at 37°C (A) alone, in the presence of (B) the NLRP3 inhibitor MCC950 (10 µM), (C) the TLR4 antagonist eritoran (1 µg/mL), or (D–F) Pep19‐2.5. IL‐1β release was determined from cell‐free supernatants by ELISA. Data shown in (A) mean + SD of duplicate analyses and are representative for n = 7 independent donors. Data in (B–E) were normalized to 100% for HDM in the absence of inhibitors and are shown as mean + SEM of (B, C, E, F): n = 5 and (D): n = 3 independent experiments with cells from different healthy donors. Statistical significance against HDM alone was analyzed by a two‐sided t ‐test. (G) Treatment protocol for HDM‐induced allergic asthma mouse model. (H) Airway resistance in response to methacholine inhalation, (I) inflammatory cell infiltrate volume in lung tissue per epithelial basal membrane (b.m.) area, and (J) numbers of eosinophils on day 14 in bronchoalveolar lavage (BAL) fluid of healthy (PBS), asthmatic (HDM), or Pep19‐2.5‐treated mice (HDM + peptide), n = 10 mice per group. (K–O) Cytokine levels in BAL fluid were assessed by MSD U‐Plex assays. (P) Caspase‐1 mRNA expression in BAL cells and (Q) caspase‐1 protein determined by Western blot. (R) Final body weight on day 14 of the treatment protocol. Results are presented as mean values ± SEM. Statistical significance was assessed using ordinary one‐way ANOVA and Tukey´s multiple comparison post hoc analyses.

Article Snippet: The fluorogenic caspase‐1 substrate Ac‐YVAD‐AMC (HY‐P2717, MedChemExpress, NJ, USA) was added to a final concentration of 10 μM.

Techniques: In Vitro, In Vivo, Enzyme-linked Immunosorbent Assay, Membrane, Expressing, Western Blot, Comparison

Journal: Advanced Science

Article Title: Membrane‐Active Peptide Protects Against Inflammation by Targeting NLRP3 Activation at the Trans‐Golgi Network

doi: 10.1002/advs.76587

Figure Lengend Snippet: Pre‐incubation with Pep19‐2.5 inhibits nigericin‐ and MSU crystal‐induced IL‐1β secretion. (A) Primary monocytes were primed with 1 µg/mL Pam 3 CSK 4 for 3 h and then stimulated with 10 µM nigericin or 200 µg/mL MSU crystals for 3 h. Pep19‐2.5 was added 30 min before priming at increasing concentrations ranging from 0.4 to 18 µM. Supernatants were analyzed for IL‐1β by ELISA. Stimulus‐induced IL‐1β secretion was set to 100%. Mean ± SEM ( n = 4 biologically independent experiments for nigericin, n = 2 biologically independent experiments for MSU crystals). One‐sample t ‐test against 100%. (B) hMDMs were primed with 1 µg/mL Pam 3 CSK 4 for 4 h and then stimulated with 5 µM nigericin for 2 h. Pep19‐2.5 was added at the indicated concentrations 30 min before priming. Supernatants were analyzed for IL‐1β by ELISA. Stimuli‐induced IL‐1β secretion was set to 100%. Mean + SEM ( n = 4 biologically independent experiments). One‐sample t ‐test against 100%. (C) THP‐1 macrophages were primed and stimulated as described in (A). For inhibition experiments, 18 µM Pep19‐2.5 was added 30 min before priming. Supernatants were analyzed for IL‐1β by ELISA. Stimulus‐induced IL‐1β secretion was set to 100%. Mean + SEM ( n = 4 biologically independent experiments for nigericin, n = 3 biologically independent experiments for MSU crystals). One‐sample t ‐test against 100%. (D and E) THP‐1 macrophages were primed and treated with NLRP1 (D) or AIM2 (E) activators. Supernatants were analyzed for IL‐1β by ELISA. Stimulus‐induced IL‐1β secretion was set to 100%. Mean + SEM ( n = 3 biologically independent experiments). One‐sample t ‐test against 100%. (F–H) Protein expression of pro‐IL‐1β (F), full‐length (G), and cleaved GSDMD (H) were analyzed by Western blot. Basal, Pam 3 CSK 4 ‐ or nigericin‐induced expression was set to 100%. Mean + SEM ( n = 3 biologically independent experiments). One‐sample t ‐test against 100%. (I) THP‐1 macrophages were primed and stimulated after peptide incubation as described in (A). After 1 h of stimulation with nigericin, the medium was removed, and Z‐WEHD buffer was added according to the manufacturer´s protocol. Ac‐YVAD‐CHO control was subtracted, and stimulus‐induced caspase‐1 activity was normalized to 100%. Mean ± SEM ( n = 3 biologically independent experiments). One‐sample t ‐test against 100%. (J) hMDMs from healthy donors were seeded in µ‐Slides VI and incubated at 37°C in a humidified atmosphere of 5% CO 2 for 1 h. Macrophages were primed with 1 µg/mL Pam 3 CSK 4 for 3 h and stimulated with 10 µM nigericin for 1 h in the presence of fluorophore‐conjugated Rh‐Pep19‐2.5. Active caspase‐1 was stained with the caspase‐1 pseudosubstrate FLICA660‐YVAD‐FMK. Cells were washed and fixed, and nuclei were stained with Hoechst 34580. Confocal microscopy images are representative of n = 2 biologically independent experiments. Scale bar is 10 µm (upper panel) and 2 µm (zoomed in lower panel). (K) Solutions containing 0.5 µM Atto488‐conjugated Pep19‐2.5 were prepared in the presence of increasing concentrations of recombinant human caspase‐1 and incubated overnight at 4°C under gentle agitation. Microfluidic diffusional sizing (MDS) measurements were performed at room temperature to determine the hydrodynamic radius ( R h ) of fluorescently labeled particles. Dots represent the mean ± SD of replicates ( n ≥ 3) of free peptide and peptide–protein complexes, and the black line represents the best nonlinear fit according to Equation . (L) Human recombinant caspase‐1 was incubated with the caspase‐1‐specific substrate Ac‐YVAD‐AMC at the indicated concentrations of Pep19‐2.5 or 40 µM of the caspase‐1 inhibitor VX765. Enzyme activity in relative fluorescence units (RFU) was measured every 2 min at 37°C. Representative traces are means ± SEM ( n = 2 biologically independent experiments).

Article Snippet: For this purpose, Pep19‐2.5 or the specific caspase‐1 inhibitor VX765 (HY‐13205, MedChemExpress, NJ, USA) was added in triplicates to the assay buffer (pH = 7.4) consisting of 50 mM HEPES, 100 mM NaCl, 0.1% CHAPS (w/v), 1 mM EDTA, 10% glycerol (v/v), and 10 mM DTT.

Techniques: Incubation, Enzyme-linked Immunosorbent Assay, Inhibition, Expressing, Western Blot, Control, Activity Assay, Staining, Confocal Microscopy, Recombinant, Gentle, Labeling, Fluorescence

Journal: Advanced Science

Article Title: Membrane‐Active Peptide Protects Against Inflammation by Targeting NLRP3 Activation at the Trans‐Golgi Network

doi: 10.1002/advs.76587

Figure Lengend Snippet: Pep19‐2.5 inhibits NLRP3‐induced ASC assembly but does not bind to NLRP3. (A) Representative Western blot of cross‐linked cytosolic pellet from primed THP‐1 macrophages that were pre‐incubated with increasing concentrations of Pep19‐2.5 and stimulated with 10 µM nigericin for 1 h ( n = 3 biologically independent experiments). (B) HEK293 ASC‐BFP cells transduced with NLRP3 were pre‐incubated with increasing concentrations of Pep19‐2.5 or MCC950 and stimulated with nigericin. ASC speck formation was determined by flow cytometry. Dot plots show mean ± SEM ( n = 3 biologically independent experiments). One‐way ANOVA followed by Dunnet's post‐test. (C) THP‐1 C1C‐EGFP macrophages were incubated with the indicated concentrations of Pep19‐2.5 for 30 min prior to priming. After priming with Pam 3 CSK 4 , 40 µM VX765 was added to limit cell death, and 10 µM nigericin was added to stimulate NLRP3 assembly for 1 h. Staining was performed using an anti‐ASC antibody and Hoechst 34580. Confocal microscopy images are representative of n = 2 biologically independent experiments, with three individual images taken for each condition. Scale bar = 20 µm. Full images are shown Figure . (D) Nuclei, ASC, and C1C specks in the images shown in (C) were quantified separately in the corresponding fluorescence channels. For each condition, three independent microscopy images were analyzed, with each data point representing a single image. Speck formation was quantified manually, and results are presented as mean + SEM. One‐way ANOVA followed by Šídák's multiple comparison post hoc analysis. (E) Melting temperature of NLRP3 NACHT alone, with the inhibitor MCC950 or Pep19‐2.5, as determined by nanoDSF ( n = 3 independent experiments). No shift upon addition of Pep19‐2.5 is observed, indicating no direct interaction of Pep19‐2.5 with the NACHT domain of NLRP3. (F) The thermal stability of the decameric NLRP3 (fl., wt) protein with and without Pep19‐2.5 was determined by measuring the hydrodynamic radius by DLS ( n = 3 independent experiments).

Article Snippet: For this purpose, Pep19‐2.5 or the specific caspase‐1 inhibitor VX765 (HY‐13205, MedChemExpress, NJ, USA) was added in triplicates to the assay buffer (pH = 7.4) consisting of 50 mM HEPES, 100 mM NaCl, 0.1% CHAPS (w/v), 1 mM EDTA, 10% glycerol (v/v), and 10 mM DTT.

Techniques: Western Blot, Incubation, Transduction, Flow Cytometry, Staining, Confocal Microscopy, Fluorescence, Microscopy, Comparison, Nano Differential Scanning Fluorimetry

Journal: Advanced Science

Article Title: Membrane‐Active Peptide Protects Against Inflammation by Targeting NLRP3 Activation at the Trans‐Golgi Network

doi: 10.1002/advs.76587

Figure Lengend Snippet: Pep19‐2.5 reduces pro‐inflammatory IL‐1β response to house dust mite extract in vitro and in vivo. (A–E) Human macrophages from heathy donors were seeded in serum‐free Opti‐MEM medium and stimulated without priming with the indicated doses of house dust mite (HDM) extract for 24 h at 37°C (A) alone, in the presence of (B) the NLRP3 inhibitor MCC950 (10 µM), (C) the TLR4 antagonist eritoran (1 µg/mL), or (D–F) Pep19‐2.5. IL‐1β release was determined from cell‐free supernatants by ELISA. Data shown in (A) mean + SD of duplicate analyses and are representative for n = 7 independent donors. Data in (B–E) were normalized to 100% for HDM in the absence of inhibitors and are shown as mean + SEM of (B, C, E, F): n = 5 and (D): n = 3 independent experiments with cells from different healthy donors. Statistical significance against HDM alone was analyzed by a two‐sided t ‐test. (G) Treatment protocol for HDM‐induced allergic asthma mouse model. (H) Airway resistance in response to methacholine inhalation, (I) inflammatory cell infiltrate volume in lung tissue per epithelial basal membrane (b.m.) area, and (J) numbers of eosinophils on day 14 in bronchoalveolar lavage (BAL) fluid of healthy (PBS), asthmatic (HDM), or Pep19‐2.5‐treated mice (HDM + peptide), n = 10 mice per group. (K–O) Cytokine levels in BAL fluid were assessed by MSD U‐Plex assays. (P) Caspase‐1 mRNA expression in BAL cells and (Q) caspase‐1 protein determined by Western blot. (R) Final body weight on day 14 of the treatment protocol. Results are presented as mean values ± SEM. Statistical significance was assessed using ordinary one‐way ANOVA and Tukey´s multiple comparison post hoc analyses.

Article Snippet: For this purpose, Pep19‐2.5 or the specific caspase‐1 inhibitor VX765 (HY‐13205, MedChemExpress, NJ, USA) was added in triplicates to the assay buffer (pH = 7.4) consisting of 50 mM HEPES, 100 mM NaCl, 0.1% CHAPS (w/v), 1 mM EDTA, 10% glycerol (v/v), and 10 mM DTT.

Techniques: In Vitro, In Vivo, Enzyme-linked Immunosorbent Assay, Membrane, Expressing, Western Blot, Comparison