Figure 1. NALP7 forms an inflammasome to facilitate IL-1β release in response to LPS and Pam3CSK4.

(a) A representative z-stack confocal microscopy image obtained by immunofluoresence co-staining of NALP7 (green), ASC (red) and DAPI (blue) in PMA-differentiated THP-1 cells (5 × 10⁵ per ml) following treatment for 4 h with LPS (100 ng ml⁻¹). The 3D image is shown in XY, XZ and YZ coordinate planes. Scale bar, 10 μm. (b) Representative images obtained by immunofluorescence co-staining as above in PMA-differentiated THP-1 cells following treatment for 4 h with LPS (200 ng ml⁻¹), Pam3CSK4 (100 ng ml⁻¹) or vehicle control. Original magnification was × 100, Scale bar, 10 μm. (c) THP-1 cells transfected with NALP3, ASC, or NALP7 siRNA followed by treatment with LPS (200 ng ml⁻¹) or Pam3CSK4 (100 ng ml⁻¹) for 6 h secreted less IL-1β as measured by ELISA compared to luciferase (LUC) siRNA control. Data shown as mean±s.d. (n=3). *P<0.05 compared to LUC control. (d,e) Immunoreactive NALP7 and NALP3 increased over time from lysates of THP-1 cells after (d) LPS (200 ng ml⁻¹) or (e) Pam3CSK4 (100 ng ml⁻¹) exposure for the indicated duration. Right, densitometric analysis of the NALP7 signal versus time, normalized to β-actin. Data shown as mean±s.d. (n=3). *P<0.05 compared to 0 h. (c) Two-way analysis of variance (ANOVA) with post hoc Dunnett's multiple comparisons test. (d,e) One-sample t-test (hypothetical value=1).