Recent studies have identified a variety of NLRP3 inflammasome activators

including whole live bacteria, fungal and viral pathogens, as well as various AZD0530 in vivo microbial-associated molecular patterns and DAMPs [2]. In addition, cellular stress triggered by factors ranging from oxidative stress to lysosomal damage appears sufficient to activate NLRP3 [3]. The mechanisms by which these molecules of diverse origins and structures can each trigger the NLRP3 inflammasome remain unclear. However, the generation of ROS seems to be a unifying factor, consistently mediating NLRP3 activation across several stimuli [4]. Recently, Zhou and colleagues demonstrated that mitochondrial (mt) ROS are critical for NLRP3 inflammasome activation [5]. Accumulation of ROS-producing mitochondria either by repressing mitochondrial autophagy or by pharmacological inhibition of the mitochondrial electron transport chain resulted in increased release of

IL-1β and IL-18 in response to LPS and ATP, or exposure to monosodium urate (MSU) crystals [5, 6]. The role played by NLRP3 in mediating release of IL-1β is well established, but it remains unclear whether the NLRP3 inflammasome might also have cytokine-independent impacts on host cell responses by acting through alternative pathways. We therefore employed MSU crystals, which elicit robust ROS production and consequently oxidative stress, but not IL-1β release, to examine the role of NLRP3 in non-inflammatory pathways. Here, we show that the NLRP3 Selleck AZD2281 inflammasome controls cellular responses

to DNA damage after genotoxic stress driven by MSU crystals or γ-radiation. Dendritic cells (DCs) from Nlrp3−/− and casp-1−/− mice exhibited reduced levels of DNA fragmentation as a result of enhanced DNA repair activity mediated by upregulation of double-strand and base-excision DNA repair genes. Moreover, DNA damage triggered the activation of the pro-apoptotic p53 pathway in WT DCs, but less so in Nlrp3−/− and casp-1−/− cells. These findings demonstrate that the NLRP3 inflammasome plays Clomifene an important role in DNA damage responses (DDR) to oxidative and genotoxic stress, supporting cell death, and ultimately cell death associated inflammation. To identify new cytokine-independent pathways regulated by NLRP3 during oxidative stress, we used MSU crystals, which activate the NLRP3 inflammasome through production of ROS but in the absence of a priming signal do not induce IL-1β and IL-18 production [7, 8]. Cellular transcriptomes of MSU-treated DCs were generated using high-density mouse oligonucleotide Affymetrix gene arrays. Differentially expressed genes (DEGs) were identified in MSU-stimulated DCs from WT and Nlrp3−/− mice compared with their respective untreated controls.