Innate immune signaling by ZBP1-RIPK1 axis drives neuroinflammation in Alzheimer's disease
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PROVIDER: PRJNA1161423 | ENA |
REPOSITORIES: ENA
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Project description:Z-DNA is a non-canonical structure capable of activating innate immune signaling through Z-DNA-binding protein 1 (ZBP1). However, the functional significance of ZBP1-mediated detection of Z-DNA in Alzheimer's disease (AD) remains poorly defined. Here, we found that ZBP1 is amplified in AD microglia, triggering innate immune response and neuroinflammation through sensing Z-form mitochondrial DNA (mtDNA). We show that fragmented oxidized mtDNA (Ox-mtDNA), produced during oxidative stress, cleaved by mitochondria nucleases, and released via the mPTP-VDAC channel, serves as the source of Z-form mtDNA. We demonstrated that Z-DNA-activated ZBP1 engages RIPK1, promoting RIPK1 kinase activation and RIPK1-kinase dependent transcription of pro-inflammatory molecules and intracellular inflammatory signaling mediators for various inflammatory pathways. Deletion of ZBP1 or genetic inhibition of RIPK1 kinase limits the innate immune response, neuroinflammation, Aβ pathology, and behavioral deficits in an AD mouse model. Our findings demonstrate that innate immune signaling by Z-form mtDNA-ZBP1-RIPK1 axis drives microglia-mediated neuroinflammation in AD, providing new insights into the immune mechanisms underlying AD pathogenesis and revealing a potential therapeutic avenue for AD.
2025-08-22 | GSE277245 | GEO
Project description:Necroptosis is a lytic form of cell death that is mediated by the kinase RIPK3 and the pseudokinase MLKL when caspase-8 is inhibited downstream of death receptors, toll-like receptor 3 (TLR3), TLR4, and the intracellular Z-form nucleic acid sensor ZBP1. Oligomerization and activation of RIPK3 is driven by interactions with the kinase RIPK1, the TLR adaptor TRIF, or ZBP1. In this study, we use immunohistochemistry (IHC) and in situ hybridization (ISH) assays to generate a tissue atlas characterizing RIPK1, RIPK3, Mlkl, and ZBP1 expression in mouse tissues. RIPK1, RIPK3, and Mlkl were co-expressed in most immune cell populations, endothelial cells, and many mucosal epithelia. ZBP1 was expressed in many immune populations, but had more variable expression in epithelia compared to RIPK1, RIPK3, and Mlkl. Intriguingly, expression of ZBP1 was elevated in Casp8-/- Tnfr1-/- embryos prior to their succumbing to aberrant necroptosis around embryonic day 15. ZBP1 contributed to this embryonic lethality because rare Casp8-/- Tnfr1-/- Zbp1-/- mice survived until after birth. Necroptosis mediated by TRIF contributed to the demise of Casp8-/- Tnfr1-/- Zbp1-/- pups in the perinatal period. Of note, Casp8-/- Tnfr1-/- Trif-/- Zbp1-/- mice exhibited autoinflammation and morbidity, typically within 5-7 weeks of being born, which is not seen in Casp8-/- Ripk1-/- Trif-/- Zbp1-/-, Casp8-/- Ripk3-/-, or Casp8-/- Mlkl-/- mice. Therefore, after birth, loss of caspase-8 probably unleashes RIPK1-dependent necroptosis driven by death receptors other than TNFR1.
2024-04-01 | GSE254754 | GEO
Project description:The RNA editing enzyme ADAR1 is essential for suppression of innate immune activation and pathology caused by aberrant recognition of self-RNA, a role it carries out by disrupting the duplex structure of endogenous double-stranded RNA species. A point mutation in the Z-nucleic-acid binding domain (ZBD) of ADAR1 is associated with severe autoinflammatory disease. ZBP1 is the only other ZBD-containing mammalian protein and its activation can trigger both cell death and transcriptional responses via the kinases RIPK1 and RIPK3, and the protease caspase-8. Here, we show that the pathology caused by ADAR1 ZBD mutation is driven by activation of ZBP1. We found that ablation of ZBP1 fully rescued the overt pathology caused by ADAR1 mutation, without reversing the underlying inflammatory program caused by this mutation. While loss of RIPK3 partially phenocopied the protective effects of ZBP1 ablation, combined deletion of caspase-8 and RIPK3, or of caspase-8 and MLKL, unexpectedly exacerbated the pathogenic effects of ADAR1 mutation. These findings indicate that ADAR1 is a negative regulator of sterile ZBP1 activation, and that ZBP1-dependent signaling underlies the autoinflammatory pathology caused by mutation of ADAR1.
2022-06-11 | GSE200854 | GEO
Project description:The RNA editing enzyme ADAR1 is essential for suppression of innate immune activation and pathology caused by aberrant recognition of self-RNA, a role it carries out by disrupting the duplex structure of endogenous double-stranded RNA species. A point mutation in the Z-nucleic-acid binding domain (ZBD) of ADAR1 is associated with severe autoinflammatory disease. ZBP1 is the only other ZBD-containing mammalian protein and its activation can trigger both cell death and transcriptional responses via the kinases RIPK1 and RIPK3, and the protease caspase-8. Here, we show that the pathology caused by ADAR1 ZBD mutation is driven by activation of ZBP1. We found that ablation of ZBP1 fully rescued the overt pathology caused by ADAR1 mutation, without reversing the underlying inflammatory program caused by this mutation. While loss of RIPK3 partially phenocopied the protective effects of ZBP1 ablation, combined deletion of caspase-8 and RIPK3, or of caspase-8 and MLKL, unexpectedly exacerbated the pathogenic effects of ADAR1 mutation. These findings indicate that ADAR1 is a negative regulator of sterile ZBP1 activation, and that ZBP1-dependent signaling underlies the autoinflammatory pathology caused by mutation of ADAR1.
2022-08-10 | GSE200986 | GEO
Project description:The RNA editing enzyme ADAR1 is essential for suppression of innate immune activation and pathology caused by aberrant recognition of self-RNA, a role it carries out by disrupting the duplex structure of endogenous double-stranded RNA species. A point mutation in the Z-nucleic-acid binding domain (ZBD) of ADAR1 is associated with severe autoinflammatory disease. ZBP1 is the only other ZBD-containing mammalian protein and its activation can trigger both cell death and transcriptional responses via the kinases RIPK1 and RIPK3, and the protease caspase-8. Here, we show that the pathology caused by ADAR1 ZBD mutation is driven by activation of ZBP1. We found that ablation of ZBP1 fully rescued the overt pathology caused by ADAR1 mutation, without reversing the underlying inflammatory program caused by this mutation. While loss of RIPK3 partially phenocopied the protective effects of ZBP1 ablation, combined deletion of caspase-8 and RIPK3, or of caspase-8 and MLKL, unexpectedly exacerbated the pathogenic effects of ADAR1 mutation. These findings indicate that ADAR1 is a negative regulator of sterile ZBP1 activation, and that ZBP1-dependent signaling underlies the autoinflammatory pathology caused by mutation of ADAR1.
2022-08-10 | GSE200985 | GEO
Project description:Conditional deletion of Caspase-8 in epidermal keratinocytes (Casp8E-KO) causes necroptosis-driven lethal dermatitis1-7. Here, we discover that Casp8 loss leads to accumulation of cytosolic DNA responsible for the activation of a cyclic-GMP-AMP synthase (cGAS)/stimulator of interferon (IFN) gene (STING)-mediated transcriptional program. Genetic and biochemical evidence indicate that STING upregulates both Z-DNA binding protein-1 (ZBP1), and mixed lineage kinase domain-like (MLKL). Combined Casp8-deficiency- and STING-activation-driven accumulation of Z-nuclei acids, activates ZBP1 and triggers formation of a ZBP1–RIPK1–RIPK3 complex independently of FADD-RIPK1-RIPK3 complex enabling necroptosis execution. Genetically, we reveal a functional overlap between STING and ZBP1 as drivers of lethal dermatitis independently of TNFR1, uncovering a novel aetiology of necroptotic inflammation. Since gain-of-function mutations in human STING cause STING-Associated Vasculopathy with onset in Infancy (SAVI), we assessed the role of STING-induced necroptosis in SAVI’s aetiology. Chronic activation of STING in patients orchestrates a necroptotic transcriptional program which is confirmed in the N153S-SAVI preclinical mouse model where immune cell–driven pathology and lethality are remarkably rescued by RIPK3 co-deletion. These findings establish STING-driven ZBP1-mediated necroptosis as a central pathogenic mechanism in both Casp8-deficient inflammation and SAVI and suggest that targeting the ZBP1-RIPK3-MLKL axis holds therapeutic potential for interferonopathies characterised by excessive necroptosis.
2025-08-21 | GSE304254 | GEO
Project description:Abstract Background & Aims: In liver transplantation, steatotic donor livers are rapidly increasing but are more susceptible to ischemia-reperfusion (I/R) injury. This study aimed to investigate the underlying mechanisms and identify therapeutic targets. Methods: Cell death markers were determined in donor livers and animal models. Casp8f/f;Alb-Cre, Ripk1D138N/D138N, Tnf-/-, Ripk3-/-, Trif-/-, Zbp1-/- mice were fed high fat diet or choline-deficient high fat diet to induce steatotic livers and were then subjected to I/R injury to investigate the mechanisms of cell death and inflammation. Primary mouse or human hepatocytes were isolated and subjected to hypoxia-reoxygenation challenge to further elucidate the regulation mechanisms. Results: Apoptosis- and inflammation-induced injury was exacerbated in I/R process of steatotic livers, with inflammation-induced injury playing a more predominant role. In both normal and steatotic livers, caspase-8 ablation mitigated I/R injury by reducing apoptosis but not inflammation while RIPK1 kinase inhibition more effectively protected against I/R injury by alleviating both apoptosis and inflammation. Z-DNA binding protein 1 (ZBP1) but not TNF-α deficiency inhibited RIPK1 activation and protected against I/R injury in steatotic livers but not normal livers. In steatotic livers, overmuch palmitic acid triggered ZBP1 transcription through activating JNK pathway. During liver transplantation, excessive reactive oxygen species were generated during I/R injury and triggered ZBP1 oligomerization, which led to the kinase activation of RIPK1 and the subsequent aggravation of apoptosis- and inflammation-induced injury. Conclusions: ZBP1-mediated apoptosis and inflammation exacerbate steatotic liver I/R injury, which could be leveraged to protect steatotic donor livers in transplantation.
2024-06-01 | GSE254747 | GEO
Project description:ZBP1/IMP1 is an mRNA binding protein that post-transcriptionally regulates the expression of a handful mRNAs, implicated in maintaining cell polarity and adhesion. We have previously shown that ZBP1 was able to inhibit proliferation and invasiveness of breast carcinoma cells in vitro. In the current study, we utilized orthotopic breast fat pad xenografts to further investigate the ZBP1-mediated functions in breast tumorigenesis and metastasis in vivo. We used microarrays to identify important gene for breast tumor growth and metastasis in response to ZBP1 expression Total RNA was extracted from breast tumor generated from ZBP1-expression and ZBP1-nonexpression MDA231 cells and used for hybridization on Affymetrix microarrays. We sought to obtain gene expression profiles from the individual tumors and identify what genes are up-regulated or down-regulated in the presence of ZBP1. The microarray experiments and data analysis were performed in 'Gene Company Limited' in Senzheng, China. G-10 and G-13, Tumors generated from MDA231/GFP cells; I-5 and I-6, tumors generated from MDA231/ZBP1-GFP cells.
2014-10-24 | E-GEOD-62638 | biostudies-arrayexpress
Project description:Sterile neuroinflammation initiated by damage-associated molecular patterns (DAMPs) has been regarded as an important driver in Alzheimer's disease (AD) and can occur prior or independently of the deposition of extracellular amyloid-β (Aβ) plaques and intracellular tau neurofibrillary tangles (NFTs). Genetic ablation or pharmacological inhibition of GPR34 reduced microglia activation, Aβ deposition and cognition impairment. Moreover, GPR34 inhibition prevented aging associated neuroinflammation and cognition impairment without the presence of Aβ plaques.
2025-02-05 | GSE216209 | GEO
Project description:The innate immune system recognizes nucleic acids as a signature of microbial infection and initiates host-protective responses, including the production of type I IFN and proinflammatory cytokines. Z-DNA binding protein 1 (ZBP1, also known as DLM-1 or DAI) was previously identified as a dsDNA binding protein, triggering DNA-mediated activation of innate immune responses. However, mice or cells lacking ZBP1 produce normal levels of type I IFN in response to dsDNA. Therefore, the classification of ZBP1 as a true DNA sensor remains to be resolved. Here, we report that the single stranded RNA virus, influenza A virus (IAV) is a trigger of the cytosolic sensor ZBP1. Sensing of IAV infection by ZBP1 engages a novel NLRP3 inflammasome pathway that is not defined by the conventions of the canonical and non-canonical NLRP3 inflammasome pathways. Surprisingly, IAV-induced cell death was not prevented by the absence of the NLRP3 inflammasome. Instead, we identified parallel contributions from pyroptosis, necroptosis and apoptosis in the execution of ZBP1-dependent cell death, mediated by the kinase RIPK3. Overall, the ability of ZBP1 to sense IAV infection signifies a point of divergence for IAV-induced programmed cell death pathways and inflammasome activation. We used microarrays to explore the gene expression profiles differentially expressed in influenza-infected bone marrow derived macrophages (BMDM) isolated from Ifnar1-/- and wild-type mice.
2016-08-11 | E-GEOD-77611 | biostudies-arrayexpress