Fig. 6.

Inhibition of STAT3 by Stattic upregulates expression of pyroptosic genes and causes pyroptosis in macrophages. Macrophages were treated with Stattic (100 μM) for 1 h to inhibite STAT3 activation. The expression of pyroptosic genes and pyroptosic protein markers and the release of inflammatory cytokines were examined. a Stattic inhibits STAT3 phosphorylation in cells. b Stattic enhances the expression of CASP1 and GSDMD mRNA in macrophages. c Stattic enhances NLRP3, caspase1-p20 and GSDMD expression, pyroptosis-related proteins were severally elevated in S. aureus infected cells which pretreated with Stattic. d Stattic increases the production of IL-18 and IL-1β in cell culture medium. e Caspase-1 activity was enhanced by Stattic treatment. f Stattic triggers pyroptosis. Red arrows indicate large bubbles in pyroptic cells. Scale bars represent 100 μm. The resolved bands were quantified using Gel-Pro Analyzer 4.0 (Media Cybernetics, Inc., Rockville, MD, USA). *p < 0.05; **p < 0.01. n = 3 independent experiments. Error bar indicates SD