A Novel Mechanism of Mesenchymal Stromal Cell-Mediated Protection against Sepsis: Restricting Inflammasome Activation in Macrophages by Increasing Mitophagy and Decreasing Mitochondrial ROS

Figure 5

BMSCs negatively regulate the NLRP3 inflammasome in BMDMs by decreasing mitochondrial ROS (mt ROS). (a), (b) BMDMs were treated with LPS (2 μg/ml, 4 hours) and ATP (5 mM, 0.5 h) (L + A). BMSCs were cocultured with BMDMs in transwell from ATP licensing for 2 h (L + A + B). BMDMs were stained with MitoSOX (5 μM) (a) or MitoTracker Deep Red (500 nM) and MitoTracker Green (200 nM) (c) for the final 30 min and then analyzed by flow cytometry. (c) Colocalization of the NLRP3 and mitochondria. BMDMs expressing NLRP3 (green) were analyzed for the colocalization of NLRP3 with the mitochondria (red) using confocal microscopy. Scale bar, 20 μm. (d–f) Inhibition of mtROS generation abolished caspase-1 activation. Western blot analysis for caspase-1 and IL-1β in lysates (d, e) and cytokine secretion (f) of BMDMs incubated for 1 h with Mito-TEMPO (500 μM), which was followed by LPS and ATP. Error bars represent the means ± s.e.m. and . . The data are representative of three or more independent experiments.

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