The findings suggest that disulfide stress contributes to NLRP3 inflammasome activation and pyroptosis triggered by BLPs in leukemia cells, the first report linking disulfidptosis-associated disulfide stress to innate immune signaling.
Abstract
Inflammasomes are innate immune signaling platforms that activate caspase-1, which in turn cleaves gasdermin D (GSDMD) into its mature form, leading to pyroptosis, an inflammatory form of regulated necrosis. It has been reported that bacterial lipopeptides (BLPs) trigger pyroptosis through NLRP7 inflammasome activation. However, the underlying recognition mechanism remains entirely unclear, and the concept of BLP sensing by NLRP7 has not been well established. In this study, we sought to elucidate the mechanism by which BLPs induce inflammasome activation and pyroptosis in human acute myeloid leukemia cell lines. Through comprehensive analyses, we demonstrate that BLPs induce GSDMD-dependent pyroptosis not via the NLRP7 inflammasome, but through the NLRP3 inflammasome without the need for additional stimuli. Addition of KCl to the culture medium significantly suppressed BLP-induced pyroptosis, suggesting the involvement of K
+
efflux in inflammasome activation. However, BLPs alone are generally thought to be insufficient to directly induce K
+
efflux, and K
+
channel inhibitors had minimal effects, prompting us to hypothesize that K
+
efflux might result from sublethal membrane damage associated with a distinct cell death mechanism. Among several cell death inhibitors tested, reducing agents, inhibitors of disulfidptosis, which is necrotic cell death caused by excessive disulfide bonding in the actin cytoskeleton, markedly attenuated BLP-induced K
+
efflux and pyroptosis. Consistent with this, BLP stimulation led to NADPH depletion and increased disulfide bond formation in β-actin, hallmarks of disulfidptosis. These findings suggest that disulfide stress contributes to NLRP3 inflammasome activation and pyroptosis triggered by BLPs in leukemia cells. To our knowledge, this is the first report linking disulfidptosis-associated disulfide stress to innate immune signaling, providing a conceptual framework for exploiting pyroptosis induction in leukemia cells.
NACHT-, LRR- and pyrin domain-containing protein 3 (NLRP3) is an intracellular sensor that detects exogenous pathogenic invasions and endogenous cellular damage, leading to the NLRP3 inflammasome activation, which plays vital roles in host defense and contributes to the pathogenesis of inflammatory diseases, such as acute peritonitis and gout. Therefore, targeting NLRP3 or other signaling molecules downstream has the potential therapeutic benefit. However, effective, low-toxic and clinically promising targeted inhibitors of NLRP3 inflammasome need to be further studied. Through compound library screening, we verified that 4-methylcatechol (4-MC), a polyphenol metabolite of quercetin, inhibited the activation of NLRP3 inflammasome at a low concentration without cytotoxicity, while did not affect the Nuclear Factor kappa B (NF-κB) activation. Mechanistically, 4-MC had no effect on NLRP3 expression, but its inhibitory effect on NLRP3 activation was restrained by increased intracelluar ROS. Moreover, 4-MC significantly ameliorated alum-induced peritonitis and LPS-induced sepsis in vivo. Thus, our research proposes a potential therapeutic drug for the intervention of NLRP3-related inflammatory diseases.
Danhui Qin, Yue Fu, Hongyi Kong et al.· European Journal of Pharmaco...· 0 citations
Deoxynivalenol (DON), a common food contaminant, induces pyroptosis in intestinal epithelial cells by activating the NLRP3 inflammasome, though the mechanism remains unclear. This study utilized 32 male Kunming mice and rat small intestinal epithelial (IEC-6) cells treated with DON at concentrations of 0-4.8 mg/kg (7 days) and 0-1 μM (24 h), respectively. Results demonstrated that DON induced intestinal epithelial damage and activated the NLRP3 inflammasome, leading to pyroptosis, while also activating the TLR4-NF-κB/p38 MAPK pathway. Pretreatment with PDTC (NF-κB inhibitor) and SB203580 (p38 MAPK inhibitor) suppressed NLRP3 inflammasome priming and activation, respectively, reducing pyroptosis in IEC-6 cells. TLR4 inhibition with TLR4-IN-C34 confirmed that TLR4 acts as an upstream regulator controlling both NF-κB and p38 MAPK signaling, thus inhibiting NLRP3 inflammasome activation and alleviating pyroptosis. Thus, DON activates the TLR4-NF-κB/p38 MAPK pathway, triggering NLRP3 inflammasome priming and activation, which ultimately leads to pyroptosis in intestinal epithelial cells.
Wang-Yong Yu, Ya-Fei Sun, Ming-Yue Wang et al.· Ecotoxicology and Environmen...· 0 citations
The NLRP3 inflammasome plays a central role in innate immunity and inflammatory diseases, yet effective inhibitors remain limited. Here, we identified vilazodone, an FDA-approved antidepressant, as a potent inhibitor of NLRP3 inflammasome activation by small-molecule screening. Vilazodone significantly suppressed IL-1β secretion in multiple macrophage models in response to diverse NLRP3 stimuli. Mechanistically, vilazodone did not affect the priming step but selectively inhibited inflammasome activation. It disrupted NLRP3 interactions with NEK7 and ASC, thereby blocking inflammasome assembly, caspase-1 activation, and downstream pyroptosis, as evidenced by reduced gasdermin D cleavage. DARTS and CETSA assays indicated that vilazodone directly binds to NLRP3, with CETSA showing increased thermal stability and DARTS showing increased resistance to proteolysis. Domain-mapping and molecular simulations further indicated that vilazodone targets the NACHT domain and forms a stable complex primarily driven by van der Waals interactions. Vilazodone also inhibited NLRC4 inflammasome activation but showed minimal effects on AIM2 inflammasome activation. Importantly, vilazodone exerted anti-inflammatory effects in vivo, reducing cytokine production in mouse models of MSU-induced peritonitis and LPS-induced systemic inflammation. Collectively, these findings identify vilazodone as a direct inhibitor of NLRP3 inflammasome assembly and highlight its potential for repurposing in inflammasome-driven diseases.
Xiang-Yu Yang, Guifang Xiong, Jie Yang et al.· International Immunopharmaco...· 0 citations
Microglia are the resident immune cells of the brain and serve as key regulators of innate immune responses within the central nervous system (CNS). The NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is a multiprotein complex that plays a central role in innate immunity, and its excessive activation contributes to the pathogenesis of neurodegenerative diseases. Nilotinib, a second-generation tyrosine kinase inhibitor, has recently attracted attention due to its neuroprotective and immunomodulatory properties in the CNS. In the present study, we investigated the effects of nilotinib on NLRP3 inflammasome activation, GSDMD/NINJ1-mediated pyroptosis, NF-κB signaling, BAG3-dependent aggrephagy, and ESCRT-III-mediated plasma membrane repair in LPS plus ATP-induced murine N9 microglial cells. Our findings demonstrated that nilotinib significantly attenuated NLRP3 inflammasome activation, as evidenced by reduced NLRP3 expression, decreased caspase-1 activation, and suppressed secretion of proinflammatory cytokines IL-1β and IL-18 through modulation of the IκBα/NF-κB signaling axis. Furthermore, nilotinib markedly inhibited pyroptotic cell death by reducing GSDMD-N and NINJ1 expression, thereby preserving membrane integrity. In parallel, nilotinib enhanced BAG3-dependent selective autophagy and increased LC3B expression, suggesting activation of aggrephagy pathways involved in the clearance of inflammasome-associated components. Notably, nilotinib also restored VPS4A expression, indicating activation of ESCRT-III-mediated plasma membrane repair mechanisms. Collectively, our results reveal that nilotinib exerts a multi-layered regulatory effect on microglial inflammatory responses by suppressing inflammasome activation and pyroptosis while promoting autophagy-dependent clearance and membrane repair pathways. These findings highlight a novel integrative mechanism linking autophagy, pyroptosis, and membrane repair in the neuroprotective actions of nilotinib.
Mehmet Erdem, Şeniz Erdem, S. Karahan· Journal of Neuroimmunology· 0 citations
The NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome plays a crucial role in host defense; however, its aberrant activation leads to excessive release of pro-inflammatory cytokines, triggering inflammatory responses and tissue damage in human diseases. In this study, the inhibitory effect and anti-inflammatory potential of carabrone on the NLRP3 inflammasome were systematically evaluated. Carabrone suppressed lipopolysaccharide (LPS) + ATP/Nigericin-induced IL-1β secretion, Caspase-1 activation, and apoptosis-associated speck-like protein (ASC) speck formation. Mechanistic investigations revealed that carabrone inhibited the NLRP3-NEK7 interaction and bound to Gln 624 and Ser 658 within the NACHT domain of NLRP3, thereby stabilizing the local conformation and inhibiting inflammasome activation. In addition, carabrone showed protective effects in Alzheimer's disease (AD) models, which were associated with NLRP3 inflammasome inhibition. Similar effects were also observed in other NLRP3 inflammasome-related disease models, including sepsis, gouty arthritis, and acute peritonitis. Collectively, these results indicate that carabrone might act as a modulator of NLRP3 inflammasome activation across multiple inflammatory disease contexts.
Bin Jia, Abuduwaili Zulalai, Huai-Ping Tang et al.· European Journal of Pharmaco...· 0 citations
Deletion of MEX3B inhibited caspase-4 and gasdermin D activation, pyroptosis, and secretion of inflammasome-dependent inflammatory cytokines in human cell lines and murine primary macrophages and suggested that MEX3B is a pan-inflammasome regulator targeting inflammatory caspases.
Peng-Hua Wang, Jason G. Cahoon, Duo-Meng Yang et al.· Journal of Immunology· 0 citations
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