Figure 6: CagA impairs inflammasome activation by disrupting NLRP3-MARK4 interaction.

(a) CagA peptide impaired the interaction between NLRP3 and MARK4 upon NLRP3 inflammasome activation by nigericin (3 μM for 2 h) in the differentiated THP-1 cells. A control peptide was employed. Scale bar, 10 μm. (b) ELISA of IL-1β level in the supernatants of WT BMDM cells following pretreatment of CagA peptide (with indicated concentrations) and nigericin stimulation (10 μM for 1 h). Mark4 KO cells were used as controls. (c) CagA peptide prevented formation of Nlrp3 and Asc complex under nigericin stimulation (3 μM for 2 h) in WT BMDMs. Mark4 KO cells were used as controls. Scale bar, 10 μm. Mean±s.e.m. for all the cells taken from five different views at × 40 magnification for each group (a,c). (d) CagA peptide impaired the formation of NLRP3 speck on MTOC upon NLRP3 inflammasome activation (MSU 250 μg ml⁻¹ for 6 h) in the differentiated THP-1 cells. Inset was used to display magnification of the boxed region as examples of MARK4, NLRP3, and γ-tubulin localization. Scale bar, 20 μm. Mean±s.e.m., at least three experiments (a–d). Comparisons of the two different groups were analysed by unpaired t test. NS was considered as not statistically significant. *P<0.05, **P<0.01, ***P<0.001 and ****P<0.0001 were considered as statistically significant (a–d).