Caspase-8 silences cell death-independent constitutive immune activation driven by tonic TNF-α
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE288233 | GEO | 2026/03/19
REPOSITORIES: GEO
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Project description:The execution of shock following high dose E. coli lipopolysaccharide (LPS) or bacterial sepsis in mice required pro-apoptotic caspase-8 in addition to pro-pyroptotic caspase-11 and gasdermin d. Hematopoietic cells produced MyD88- and TRIF-dependent inflammatory cytokines sufficient to initiate LPS shock independent of caspase-8 or caspase-11. Both proteases had to be present to support tissue injury, dependent upon TNF and interferon , first observed in the small intestine and later in spleen and thymus. Caspase-11 enhanced the activation of caspase-8 and extrinsic cell death machinery within the lower small intestine. Neither caspase-8 nor caspase-11 was individually sufficient for shock, but collaborated to amplify the inflammatory signals associated with tissue injury. Therefore, combined pyroptotic and apoptotic signaling mediated endotoxemia independent of RIPK1 kinase activity and RIPK3 function. These observations bring to light the relevance of tissue compartmentalization during inflammatory signaling in vivo where cytokines execute diverse cell death pathways and tissue damage.
2018-08-07 | GSE115094 | GEO
Project description:Expression of the activating transcription factor 3 (ATF3) gene is induced by Toll-like receptor (TLR) signaling. In turn, ATF3 protein inhibits the expression of various TLR-driven pro-inflammatory genes. Given its counter-regulatory role in diverse innate immune responses, we defined the effects of ATF3 on neutrophilic airway inflammation in mice. ATF3 deletion was associated with increased lipopolysaccharide (LPS)-driven airway epithelia production of CXCL1, but not CXCL2, findings concordant with a consensus ATF3-binding site identified solely in the Cxcl1 promoter. Unexpectedly, ATF3-deficient mice did not exhibit increased airway neutrophilia after LPS challenge. Bone marrow chimeras revealed a specific reduction in ATF3-/- neutrophil recruitment to wild type lungs. In vitro, ATF3-/- neutrophils exhibited a profound chemotaxis defect. Global gene expression analysis identified ablated Tiam2 expression in ATF3-/- neutrophils. TIAM2 regulates cellular motility by activating Rac1-mediated focal adhesion disassembly. Notably, ATF3-/- and ATF3-sufficient TIAM2 knockdown neutrophils, both lacking TIAM2, exhibited increased focal complex area, along with excessive CD11b-mediated F-actin polymerization. Together, our data describe a dichotomous role for ATF3-mediated regulation of neutrophilic responses: inhibition of neutrophil chemokine production, but promotion of neutrophil chemotaxis. Ly6G+ neutrophils were purified by magnetic beads from WT or ATF3 KO bone marrow and RNA was immediately isolated for global gene expression using microarrays.
2014-04-05 | E-GEOD-53973 | biostudies-arrayexpress
Project description:S100A8/A9 is a proinflammatory mediator released by myeloid cells during many acute and chronic inflammatory disorders. However, the precise mechanism of its release from the cytosolic compartment of neutrophils is still elusive. We report here that E-selectin-induced rapid S100A8/A9 release during inflammation occurs in a NLRP3 inflammasome-dependent fashion. Mechanistically, E-selectin engagement triggers Bruton?s tyrosine kinase dependent tyrosine phosphorylation of NLRP3. Concomitant potassium efflux via the voltage-gated potassium channel KV1.3 mediates ASC oligomerization. This is followed by caspase-1 cleavage and downstream activation of pore forming gasdermin D, enabling cytosolic S100A8/A9 to be released. Strikingly, E-selectin-mediated gasdermin D pore formation does not result in cell death, but is a transient process involving activation of the ESCRT-III membrane repair machinery. These findings do not only elucidate the molecular mechanisms of controlled S100A8/A9 release but also identify the NLRP3/gasdermin D axis as a rapid and reversible activation system in neutrophils during inflammation.
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Project description:Neutrophils play a crucial role in instigating inflammation as well as its resolution postmyocardial infarction (MI). Although granulopoiesis in the bone marrow (BM) is the major source of cardiac neutrophils post-MI, infiltration of neutrophils to the heart occurs much quicker than peak granulopoiesis. Using a combination of flow cytometry, BM ablation of hematopoietic stem cells, confocal microscopy and multiple proteomics analysis, we found that the first wave of neutrophils recruited to the ischemic heart is exclusively sourced from vasculature and not from granulopoiesis in the BM/ spleen. The MIevoked neutrophilia during the early hours bore all hallmarks of demargination induced by classical demarginating agents such as dexamethasone/ norepinephrine (NE). Various pharmacological and genetic strategies aimed at suppressing NE synthesis or disruption of β-AR signaling reduced both neutrophil demargination as well as recruitment to the heart. Interestingly, however, despite a marked reduction in cardiac neutrophil burden only short-term inhibition of β-ARs improved cardiac remodeling and function. Our findings support a pharmacological strategy to contain the initial onslaught of neutrophils on the ischemic heart using β2-AR blockers to regulate the otherwise runaway inflammatory response.
2026-03-20 | PXD074944 | Pride
Project description:Neutrophils play a key role in the innate immunity and the first line of defense against invading pathogens. The aim of this work is to investigate the neutrophil responses and transcriptomic alteration in the porcine peripheral blood by employing Poly I:C to emulate viral infection. The pigs with the two-tailed critical value of neutrophilia post 4h with poly I:C stimulation from a Duroc-Erhualian F2 population.
2017-08-30 | E-MTAB-4928 | biostudies-arrayexpress
Project description:Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potential cancer therapeutic that selectively induces apoptosis in cancer cells sparing the non-malignant cells. While the effective cytotoxic effect of TRAIL has been demonstrated in vitro, its efficacy in clinical trials has been limited, suggesting a presence of unknown modulatory mechanisms responsible for lack of TRAIL activity in patients. We hypothesized that TRAIL treatment elicits transcriptional changes in triple negative breast cancer cells (TNBC) cells that alter the immune milieu. To test this, we performed a RNAseq analysis of MDA-MB-231 cells treated with TRAIL, followed by validation in various TNBC cell lines. We found that TRAIL significantly induces expression of multiple cytokines, such as CXCLs 1, 2, 3, 8,11 and IL-6, which are known to affect neutrophil function. Gene set enrichment analysis (GSEA) indicated a significant enrichment of NFKB pathway. Concordantly, we confirmed that the non-canonical NFKB2 pathway is primarily responsible for induction of these cytokines. We further found that induction of these cytokines was predominantly mediated by death receptor 5 and caspase-8 protein, but not caspase-8 enzymatic activity. CXCLs and IL-6 produced by the TRAIL-treated TNBC cells enhanced chemotaxis of neutrophils isolated from healthy human donors, demonstrating the functional relevance of these cytokines. In vivo, TNBC xenograft tumors grown in mice treated with TRAIL showed an activation of the NFKB2 pathways, elevated production of CXCLs and IL-6, and an increased neutrophil recruitment into the tumors. Moreover, pre-incubation of neutrophils from human donor with supernatants from TRAIL-treated TNBC cells significantly impaired the cytotoxic effect against TNBC cells and showed a reduced respiratory burst. Transcriptomic analysis of neutrophils incubated with either TRAIL alone or supernatant of TRAIL-treated TNBC revealed significant enrichment of expression of inflammatory cytokines, immune modulatory genes, and immune checkpoint genes along with genes having implication on delayed neutrophil apoptosis. Functional studies with these neutrophils confirmed their suppressive effect on T cell proliferation and an increase in Treg suppressive phenotype. Collectively, our study proposes the novel role of TRAIL-induced NFKB2-dependent cytokine production that promotes neutrophil chemotaxis and immune suppression. Our finding suggests that targeting innate immune system may be a promising strategy to improve the efficacy of TRAIL treatment in TNBC.
2025-05-07 | GSE271122 | GEO
Project description:Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potential cancer therapeutic that selectively induces apoptosis in cancer cells sparing the non-malignant cells. While the effective cytotoxic effect of TRAIL has been demonstrated in vitro, its efficacy in clinical trials has been limited, suggesting a presence of unknown modulatory mechanisms responsible for lack of TRAIL activity in patients. We hypothesized that TRAIL treatment elicits transcriptional changes in triple negative breast cancer cells (TNBC) cells that alter the immune milieu. To test this, we performed a RNAseq analysis of MDA-MB-231 cells treated with TRAIL, followed by validation in various TNBC cell lines. We found that TRAIL significantly induces expression of multiple cytokines, such as CXCLs 1, 2, 3, 8,11 and IL-6, which are known to affect neutrophil function. Gene set enrichment analysis (GSEA) indicated a significant enrichment of NFKB pathway. Concordantly, we confirmed that the non-canonical NFKB2 pathway is primarily responsible for induction of these cytokines. We further found that induction of these cytokines was predominantly mediated by death receptor 5 and caspase-8 protein, but not caspase-8 enzymatic activity. CXCLs and IL-6 produced by the TRAIL-treated TNBC cells enhanced chemotaxis of neutrophils isolated from healthy human donors, demonstrating the functional relevance of these cytokines. In vivo, TNBC xenograft tumors grown in mice treated with TRAIL showed an activation of the NFKB2 pathways, elevated production of CXCLs and IL-6, and an increased neutrophil recruitment into the tumors. Moreover, pre-incubation of neutrophils from human donor with supernatants from TRAIL-treated TNBC cells significantly impaired the cytotoxic effect against TNBC cells and showed a reduced respiratory burst. Transcriptomic analysis of neutrophils incubated with either TRAIL alone or supernatant of TRAIL-treated TNBC revealed significant enrichment of expression of inflammatory cytokines, immune modulatory genes, and immune checkpoint genes along with genes having implication on delayed neutrophil apoptosis. Functional studies with these neutrophils confirmed their suppressive effect on T cell proliferation and an increase in Treg suppressive phenotype. Collectively, our study proposes the novel role of TRAIL-induced NFKB2-dependent cytokine production that promotes neutrophil chemotaxis and immune suppression. Our finding suggests that targeting innate immune system may be a promising strategy to improve the efficacy of TRAIL treatment in TNBC.
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Project description:Renal fibrosis is a common consequence of various progressive nephropathies, including obstructive nephropathy, and ultimately leads to kidney failure. Infiltration of inflammatory cells is a prominent feature of renal injury after draining blockages from the kidney, and correlates closely with the development of renal fibrosis. However, the underlying molecular mechanism behind the promotion of renal fibrosis by inflammatory cells remains unclear. Herein, we showed that unilateral ureteral obstruction (UUO) induced Gasdermin D (GSDMD) activation in neutrophils, abundant neutrophil extracellular traps (NETs) formation and macrophage-to-myofibroblast transition (MMT) characterized by α-smooth muscle actin (α-SMA) expression in macrophages. Gsdmd deletion significantly reduced infiltration of inflammatory cells in the kidneys and inhibited NETs formation, MMT and thereby renal fibrosis. Chimera studies confirmed that Gsdmd deletion in bone marrow-derived cells, instead of renal parenchymal cells, provided protection against renal fibrosis. Further, specific deletion of Gsdmd in neutrophils instead of macrophages protected the kidney from undergoing fibrosis after UUO. Single-cell RNA sequencing identified robust crosstalk between neutrophils and macrophages. In vitro, GSDMD-dependent NETs triggered p65 translocation to the nucleus, which boosted the production of inflammatory cytokines and α-SMA expression in macrophages by activating TGF-β1/Smad pathway. In addition, we demonstrated that caspase-11, that could cleave GSDMD, was required for NETs formation and renal fibrosis after UUO. Collectively, our findings demonstrate that caspase-11/GSDMD-dependent NETs promote renal fibrosis by facilitating inflammation and MMT, therefore highlighting the role and mechanisms of NETs in renal fibrosis.
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Project description:Neutrophil gene transcription following lipopolysaccharide exposure. Microarray analysis of lipopolysaccharide-treated human neutrophils. Neutrophils respond to infection by degranulation, release of reactive oxygen intermediates, and secretion of chemokines and cytokines; however, activation of neutrophil transcriptional machinery has been little appreciated. Recent findings suggest that gene expression may represent an additional neutrophil function after exposure to lipopolysaccharide (LPS). We performed microarray gene expression analysis of 4,608 mostly nonredundant genes on LPS-stimulated human neutrophils. Analysis of three donors indicated some variability but also a high degree of reproducibility in gene expression. Twenty-eight verifiable, distinct genes were induced by 4 h of LPS treatment, and 13 genes were repressed. Genes other than cytokines and chemokines are regulated; interestingly, genes involved in cell growth regulation and survival, transcriptional regulation, and interferon response are among those induced, whereas genes involved in cytoskeletal regulation are predominantly repressed. In addition, we identified monocyte chemoattractant protein-1 as a novel LPS-regulated chemokine in neutrophils. Included in these lists are five clones with no defined function. These data suggest molecular mechanisms by which neutrophils respond to infection and indicate that the transcriptional potential of neutrophils is greater than previously thought.
2010-06-05 | E-GEOD-105 | biostudies-arrayexpress