Figure 2

Nano-SiO₂- or nano-TiO₂-induced IL-1β in mouse macrophages is dependent on purinergic signalling. IL-1β production by LPS-primed BMDMs stimulated for 6 h with nano-SiO₂ or nano-TiO₂ was dose dependently decreased by P2R antagonists suramin (200, 400 or 600 μM) and oATP (100, 200 or 400 μM) (a). Cbx (50 or 100 μM) and FFA (25, 100 or 250 μM) significantly reduced IL-1β release by murine macrophages (b). Western blotting analysis of LPS-primed BMDM supernatants (SN) confirmed that FFA (100 μM), Cbx (50 μM) oATP (200 μM) or A740003 (100 μM) strongly reduced the secretion of the mature 17kD IL-1β form mIL-1β in response to nano-SiO₂ or nano-TiO₂ (c). Similarly FFA, Cbx or oATP significantly reduced autoproteolytic cleavage of the pro-caspase-1 into the secreted p10 subunit (d). Stimulation of BMDMs with ATP (5 mM, 45 min) induced mature IL-1β (c) and caspase-1 (d) releases in the supernatant, whereas nano-ZnO did not induce these cleavages (c,d). BMDM extracts (XT) prepared from the same experiments were blotted with anti-β-actin, anti-pro-IL-1β and anti-pro-caspase-1 for control (c,d). Molecular-weight markers are shown at the right (c,d). BMDMs were stimulated with 250 μg/ml nanoparticles during 6 h. Data are representative of three independent experiments. Data are mean±S.D. of triplicates, compared between nanoparticle-stimulated THP1 and nanoparticles plus inhibitor; *** and ααα, P≤0.001 for nano-SiO₂ and nano-TiO₂ stimulated THP1, respectively (a,b)