The innate sensor ZBP1-IRF3 axis regulates cell proliferation in multiple myeloma

The multiple roles of interferon regulatory factor family in health and disease

Interferon Regulatory Factors (IRFs), a family of transcription factors, profoundly influence the immune system, impacting both physiological and pathological processes. This review explores the diverse functions of nine mammalian IRF members, each featuring conserved domains essential for interactions with other transcription factors and cofactors. These interactions allow IRFs to modulate a broad spectrum of physiological processes, encompassing host defense, immune response, and cell development. Conversely, their pivotal role in immune regulation implicates them in the pathophysiology of various diseases, such as infectious diseases, autoimmune disorders, metabolic diseases, and cancers. In this context, IRFs display a dichotomous nature, functioning as both tumor suppressors and promoters, contingent upon the specific disease milieu. Post-translational modifications of IRFs, including phosphorylation and ubiquitination, play a crucial role in modulating their function, stability, and activation. As prospective biomarkers and therapeutic targets, IRFs present promising opportunities for disease intervention. Further research is needed to elucidate the precise mechanisms governing IRF regulation, potentially pioneering innovative therapeutic strategies, particularly in cancer treatment, where the equilibrium of IRF activities is of paramount importance.

Multi-omic analysis and validation reveal ZBP1 as a potential prognostic and immunotherapy-related biomarker in head and neck squamous cell carcinoma

BACKGROUND

Patients with head and neck squamous cell carcinoma (HNSCC) exhibit unfavorable clinical outcomes, accompanied by high morbidity/mortality. In recent years, the management of HNSCC has encountered a significant obstacle. Z-DNA binding protein 1 (ZBP1) exerts crucial biological functions in chronic inflammatory disease and cancer. The aim of this research was to identify the possible function of ZBP1 in HNSCC.

METHODS

The Cancer Genome Atlas (TCGA) database was used to collect the gene expression profile and corresponding clinical data. The gene expression, clinical prognosis, genetic alteration, immune characteristics, and subgroup analyses were performed. Meanwhile, an independent cohort (consisting of 66 tumor samples and 37 controls) was employed to validate the expression of ZBP1.

RESULTS

Comparing to the normal controls, ZBP1 was upregulated in tumor samples. Low ZBP1 expression predicted undesirable clinical outcomes of HNSCC patients based on the survival analysis. Furthermore, the somatic mutations increased in low ZBP1 expression group. Immune characteristics analysis indicated a positive correlation of ZBP1 expression with the infiltration of immune cells, the expression of immunoregulatory genes and immune checkpoints. In the meantime, single-cell transcriptome analysis unveiled the expression of ZBP1 in tumor microenvironment (TME). In addition, differential gene expression analysis revealed that the expression of ZBP1 primarily contributes to the activation of T cells. Ultimately, ZBP1-associated prognostic and immune features in different subgroups of HNSCC patients were further investigated according to the subgroup analysis.

CONCLUSION

Our study comprehensively disclosed that ZBP1 may have the potential to become a meaningful prognostic and immunotherapy-related biomarker for HNSCC.

Haplotype analysis identifies functional elements in monoclonal gammopathy of unknown significance

Genome-wide association studies (GWASs) based on common single nucleotide polymorphisms (SNPs) have identified several loci associated with the risk of monoclonal gammopathy of unknown significance (MGUS), a precursor condition for multiple myeloma (MM). We hypothesized that analyzing haplotypes might be more useful than analyzing individual SNPs, as it could identify functional chromosomal units that collectively contribute to MGUS risk. To test this hypothesis, we used data from our previous GWAS on 992 MGUS cases and 2910 controls from three European populations. We identified 23 haplotypes that were associated with the risk of MGUS at the genome-wide significance level (p < 5 × 10-8) and showed consistent results among all three populations. In 10 genomic regions, strong promoter, enhancer and regulatory element-related histone marks and their connections to target genes as well as genome segmentation data supported the importance of these regions in MGUS susceptibility. Several associated haplotypes affected pathways important for MM cell survival such as ubiquitin-proteasome system (RNF186, OTUD3), PI3K/AKT/mTOR (HINT3), innate immunity (SEC14L1, ZBP1), cell death regulation (BID) and NOTCH signaling (RBPJ). These pathways are important current therapeutic targets for MM, which may highlight the advantage of the haplotype approach homing to functional units.

Z-DNA binding protein 1 orchestrates innate immunity and inflammatory cell death

Innate immunity is not only the first line of host defense against microbial infections but is also crucial for the host responses against a variety of noxious stimuli. Z-DNA binding protein 1 (ZBP1) is a cytosolic nucleic acid sensor that can induce inflammatory cell death in both immune and nonimmune cells upon sensing of incursive virus-derived Z-form nucleic acids and self-nucleic acids via its Zα domain. Mechanistically, aberrantly expressed or activated ZBP1 induced by pathogens or noxious stimuli enables recruitment of TANK binding kinase 1 (TBK1), interferon regulatory factor 3 (IRF3), receptor-interacting serine/threonine-protein kinase 1 (RIPK1) and RIPK3 to drive type I interferon (IFN-I) responses and activation of nuclear factor kappa B (NF-κB) signaling. Meanwhile, ZBP1 promotes the assembly of ZBP1- and absent in melanoma 2 (AIM2)-PANoptosome, which ultimately triggers PANoptosis through caspase 3-mediated apoptosis, mixed lineage kinase domain like pseudokinase (MLKL)-mediated necroptosis, and gasdermin D (GSDMD)-mediated pyroptosis. In response to damaged mitochondrial DNA, ZBP1 can interact with cyclic GMP-AMP synthase to augment IFN-I responses but inhibits toll like receptor 9-mediated inflammatory responses. This review summarizes the structure and expression pattern of ZBP1, discusses its roles in human diseases through immune-dependent (e.g., the production of IFN-I and pro-inflammatory cytokines) and -independent (e.g., the activation of cell death) functions, and highlights the attractive prospect of manipulating ZBP1 as a promising therapeutic target in diseases.

Highly Expressed Z-DNA Binding Protein 1 in Esophageal Cancer Promotes Tumor Growth

BACKGROUND

Esophageal cancer (ESCA) is a common malignant tumor of the digestive tract, and its poor prognosis is mainly attributed to the occurrence of invasion and metastasis. Z-DNA binding protein 1 (ZBP1), as a mRNA regulatory factor, plays an important role in the occurrence and development of various tumors. However, the role of ZBP1 in ESCA is not yet understood.

AIMS

This study aims to explore the expression of ZBP1 in ESCA and its role in the development of ESCA.

METHODS

Using bioinformatics analysis and immunohistochemistry staining, we detected the expression of ZBP1 in ESCA and normal tissues. The potential mechanism of ZBP1 in ESCA was analyzed from the aspects of genetic mutations, protein interaction networks, and pathway enrichment. We performed functional experiments in vitro to elucidate the effect of ZBP1 on ESCA cells.

RESULTS

ZBP1 was found to be significantly upregulated in ESCA compared to adjacent noncancerous tissues, and its expression is closely related to gender, age, and lymph node metastasis. In ESCA, the genetic variation rate of ZBP1 is 8%, and its expression is positively correlated with immune cell infiltration. The ZBP1 co-expressed gene is mainly involved in processes such as lymph node proliferation and intercellular adhesion. In vitro experiments have confirmed that downregulation of ZBP1 significantly inhibited the proliferation, migration, and invasion of ESCA cells.

CONCLUSION

This research proves that downregulation of ZBP1 can inhibit the progression of ESCA. This finding indicates that ZBP1 may be a novel biomarker to improve the diagnosis and treatment of ESCA.

Dietary Peppermint Extract Inhibits Chronic Heat Stress-Induced Activation of Innate Immunity and Inflammatory Response in the Spleen of Broiler Chickens

The aim of this study was to investigate the effect of dietary peppermint extract (PE) on innate immunity and inflammatory responses in the spleen of broiler chickens under chronic heat stress. In order to further study the mechanism of the activation of innate immunity and inflammation induced by chronic heat stress and the regulatory effect of peppermint extract, we examined the spleen's histological change, the mRNA expression of major pattern recognition receptors (PRRs) (TLR2, TLR4, NOD1, MDA5 and DAI) and transcription factors (NF-κB, AP-1 and IRF3) and downstream inflammatory cytokines (IFN-α, IFN-β, IL-1β, IL-6 and TNF-α) of innate immune signaling pathways associated with heat stress in the spleen of broiler chickens. The results indicated that chronic heat stress damaged the spleen tissue. In addition, chronic heat stress induced the activation of innate immunity and inflammatory responses by increasing the mRNA expression of TLR2, TLR4 and DAI, mRNA expression of transcriptional factors (NF-κB, AP-1 and IRF3) and the concentration of downstream inflammatory cytokines in the spleen of broiler chickens. Dietary peppermint extract alleviated the damage of spleen tissue caused by chronic heat stress. In addition, peppermint extract reduced the mRNA expression of DAI, mRNA expression of transcriptional factors NF-κB, AP-1 and IRF3, and the concentration of inflammatory cytokines in the spleen of broiler chickens under chronic heat stress. In conclusion, dietary peppermint extract could have a beneficial effect on regulating inflammatory response and innate immunity via inhibiting the activation of NF-κB, AP-1 and IRF3 signaling pathways mediated by DAI in the spleen of broiler chickens induced by chronic heat stress.

Z-nucleic acid sensor ZBP1 in sterile inflammation

Z-DNA binding protein 1 (ZBP1), a cytosolic nucleic acid sensor for Z-form nucleic acids (Z-NA), can detect both exogenous and endogenous nucleic acids. Upon sensing of self Z-NA or exposure to diverse noxious stimuli, ZBP1 regulates inflammation by activating nuclear factor kappa B and interferon regulating factor 3 signaling pathways. In addition, ZBP1 promotes the assembly of ZBP1 PANoptosome, which initiates caspase 3-mediated apoptosis, mixed lineage kinase domain like pseudokinase (MLKL)-mediated necroptosis, and gasdermin D (GSDMD)-mediated pyroptosis (PANoptosis), leading to the release of various damage-associated molecular patterns. Thereby, ZBP1 is implicated in the development and progression of diverse sterile inflammatory diseases. This review outlines the expression, structure, and function of ZBP1, along with its dual roles in controlling inflammation and cell death to orchestrate innate immunity in sterile inflammation, especially autoimmune diseases, and cancers. ZBP1 has emerged as an attractive therapeutic target for various sterile inflammatory diseases.

Vinorelbine causes a neuropathic pain-like state in mice via STING and MNK1 signaling associated with type I interferon induction

Type I interferons (IFNs) increase the excitability of dorsal root ganglia (DRGs) neurons via MNK-eIF4E signaling to promote pain sensitization in mice. Activation of stimulator of interferon response cGAMP interactor 1 (STING) signaling is pivotal for type I IFN induction. We hypothesized that vinorelbine, a chemotherapeutic and activator of STING, would cause a neuropathic pain-like state in mice via STING signaling in DRG neurons associated with IFN production. Vinorelbine caused tactile allodynia and grimacing in wild-type (WT) mice and increased p-IRF3, type I IFNs, and p-eIF4E in peripheral nerves. Supporting our hypothesis, vinorelbine failed to induce IRF3-IFNs-MNK-eIF4E in StingGt/Gt mice and, subsequently, failed to cause pain. The vinorelbine-elicited increase of p-eIF4E was not observed in Mknk1-/- (MNK1 knockout) mice in peripheral nerves consistent with the attenuated pro-nociceptive effect of vinorelbine in these mice. Our findings show that activation of STING signaling in the periphery causes a neuropathic pain-like state through type I IFN signaling to DRG nociceptors.

Hepatocyte GPCR signaling regulates IRF3 to control hepatic stellate cell transdifferentiation

BACKGROUND

Interferon Regulatory Factor 3 (IRF3) is a transcription factor that plays a crucial role in the innate immune response by recognizing and responding to foreign antigens. Recently, its roles in sterile conditions are being studied, as in metabolic and fibrotic diseases. However, the search on the upstream regulator for efficient pharmacological targeting is yet to be fully explored. Here, we show that G protein-coupled receptors (GPCRs) can regulate IRF3 phosphorylation through of GPCR-Gα protein interaction.

RESULTS

IRF3 and target genes were strongly associated with fibrosis markers in liver fibrosis patients and models. Conditioned media from MIHA hepatocytes overexpressing IRF3 induced fibrogenic activation of LX-2 hepatic stellate cells (HSCs). In an overexpression library screening using active mutant Gα subunits and Phos-tag immunoblotting, Gαs was found out to strongly phosphorylate IRF3. Stimulation of Gαs by glucagon or epinephrine or by Gαs-specific designed GPCR phosphorylated IRF3. Protein kinase A (PKA) signaling was primarily responsible for IRF3 phosphorylation and Interleukin 33 (IL-33) expression downstream of Gαs. PKA phosphorylated IRF3 on a previously unrecognized residue and did not require reported upstream kinases such as TANK-binding kinase 1 (TBK1). Activation of Gαs signaling by glucagon induced IL-33 production in hepatocytes. Conditioned media from the hepatocytes activated HSCs, as indicated by α-SMA and COL1A1 expression, and this was reversed by pre-treatment of the media with IL-33 neutralizing antibody.

CONCLUSIONS

Gαs-coupled GPCR signaling increases IRF3 phosphorylation through cAMP-mediated activation of PKA. This leads to an increase of IL-33 expression, which further contributes to HSC activation. Our findings that hepatocyte GPCR signaling regulates IRF3 to control hepatic stellate cell transdifferentiation provides an insight for understanding the complex intercellular communication during liver fibrosis progression and suggests therapeutic opportunities for the disease. Video Abstract.

Telomeres as hotspots for innate immunity and inflammation

Aging is marked by the gradual accumulation of deleterious changes that disrupt organ function, creating an altered physiological state that is permissive for the onset of prevalent human diseases. While the exact mechanisms governing aging remain a subject of ongoing research, there are several cellular and molecular hallmarks that contribute to this biological process. This review focuses on two factors, namely telomere dysfunction and inflammation, which have emerged as crucial contributors to the aging process. We aim to discuss the mechanistic connections between these two distinct hallmarks and provide compelling evidence highlighting the loss of telomere protection as a driver of pro-inflammatory states associated with aging. By reevaluating the interplay between telomeres, innate immunity, and inflammation, we present novel perspectives on the etiology of aging and its associated diseases.

ZBP1 mediates the progression of Alzheimer's disease via pyroptosis by regulating IRF3

Alzheimer's disease (AD) is one of the leading causes of death throughout the world. Z-DNA binding protein 1 (ZBP1), a DNA-related gene, is associated with inflammation, and its expression is altered in AD brain. We aimed to elucidate the exact role of ZBP1 in AD development and its potential regulatory mechanism. First, we constructed both in vivo and in vitro models of AD and investigated the ZBP1 expression profile. A loss-of-function assay was performed by transfecting lentivirus carrying ZBP1 short hairpin RNA (shRNA). By evaluating cell death, oxidative stress, inflammation response and pyroptosis, the function of ZBP1 was validated. Finally, the correlation between ZBP1 and interferon regulatory factor 3 (IRF3) was verified. We also performed rescue experiments to validate the crucial role of IRF3 in ZBP1-mediated AD progression. According to our results, ZBP1 was upregulated in AD rat tissue and AD neurons. Silencing ZBP1 dramatically decreased cell injury, oxidative stress and inflammation in AD neurons and improved the cognitive function of AD rats. Additionally, IRF3 expression and phosphorylation were significantly elevated during AD development and positively correlated with ZBP1. Taken together, silencing ZBP1 suppressed cell injury and pyroptosis of AD neurons and improved cognitive function of AD rats via inhibiting IRF3. These findings might provide a novel insight for AD target diagnosis and therapy.

The Z-nucleic acid sensor ZBP1 in health and disease

Nucleic acid sensing is a central process in the immune system, with far-reaching roles in antiviral defense, autoinflammation, and cancer. Z-DNA binding protein 1 (ZBP1) is a sensor for double-stranded DNA and RNA helices in the unusual left-handed Z conformation termed Z-DNA and Z-RNA. Recent research established ZBP1 as a key upstream regulator of cell death and proinflammatory signaling. Recognition of Z-DNA/RNA by ZBP1 promotes host resistance to viral infection but can also drive detrimental autoinflammation. Additionally, ZBP1 has interesting roles in cancer and other disease settings and is emerging as an attractive target for therapy.

Telomere-to-mitochondria signalling by ZBP1 mediates replicative crisis

Cancers arise through the accumulation of genetic and epigenetic alterations that enable cells to evade telomere-based proliferative barriers and achieve immortality. One such barrier is replicative crisis-an autophagy-dependent program that eliminates checkpoint-deficient cells with unstable telomeres and other cancer-relevant chromosomal aberrations1,2. However, little is known about the molecular events that regulate the onset of this important tumour-suppressive barrier. Here we identified the innate immune sensor Z-DNA binding protein 1 (ZBP1) as a regulator of the crisis program. A crisis-associated isoform of ZBP1 is induced by the cGAS-STING DNA-sensing pathway, but reaches full activation only when associated with telomeric-repeat-containing RNA (TERRA) transcripts that are synthesized from dysfunctional telomeres. TERRA-bound ZBP1 oligomerizes into filaments on the outer mitochondrial membrane of a subset of mitochondria, where it activates the innate immune adapter protein mitochondrial antiviral-signalling protein (MAVS). We propose that these oligomerization properties of ZBP1 serve as a signal amplification mechanism, where few TERRA-ZBP1 interactions are sufficient to launch a detrimental MAVS-dependent interferon response. Our study reveals a mechanism for telomere-mediated tumour suppression, whereby dysfunctional telomeres activate innate immune responses through mitochondrial TERRA-ZBP1 complexes to eliminate cells destined for neoplastic transformation.

ZBP1-Mediated Necroptosis: Mechanisms and Therapeutic Implications

Cell death is a fundamental pathophysiological process in human disease. The discovery of necroptosis, a form of regulated necrosis that is induced by the activation of death receptors and formation of necrosome, represents a major breakthrough in the field of cell death in the past decade. Z-DNA-binding protein (ZBP1) is an interferon (IFN)-inducing protein, initially reported as a double-stranded DNA (dsDNA) sensor, which induces an innate inflammatory response. Recently, ZBP1 was identified as an important sensor of necroptosis during virus infection. It connects viral nucleic acid and receptor-interacting protein kinase 3 (RIPK3) via two domains and induces the formation of a necrosome. Recent studies have also reported that ZBP1 induces necroptosis in non-viral infections and mediates necrotic signal transduction by a unique mechanism. This review highlights the discovery of ZBP1 and its novel findings in necroptosis and provides an insight into its critical role in the crosstalk between different types of cell death, which may represent a new therapeutic option.

Analysis of Age-Dependent Transcriptomic Changes in Response to Intracerebral Hemorrhage in Mice

Age is a well-known risk factor that is independently associated with poor outcomes after intracerebral hemorrhage (ICH). However, the interrelationship between age and poor outcomes after ICH is not well defined. In this study, we aimed to investigate this relationship based on collagenase-induced ICH mice models. After being assessed neurological deficit 24 h after ICH, mice were euthanized and brain perihematomal tissues were used for RNA-sequencing (RNA-seq). And then the functions of differentially expressed genes (DEGs) identified by RNA-seq were analyzed using Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, Ingenuity Pathway Analysis (IPA) and protein-protein interaction (PPI) analysis. In addition, we performed real-time quantitative polymerase chain reaction (RT-qPCR) for validation of candidate DEGs. In the behavioral tests, aged mice presented significantly worse neurological function than young mice and greater weight loss than aged sham controls 24 h after ICH. In DEGs analysis, ICH affected the expression of more genes in young mice (2,337 DEGs) compared with aged mice (2,005 DEGs). We found aged mice exhibited increased brain inflammatory responses compared with young animals and ICH induced significant activation of the interferon-β (IFN-β) and IFN signaling pathways exclusively in aged mice. Moreover, further analysis demonstrated that ICH resulted in the activation of cytosolic DNA-sensing pathway with the production of downstream molecule type I IFN, and the response to type I IFN was more significant in aged mice than in young mice. In agreement with the results of RNA-seq, RT-qPCR indicated that the expression of candidate genes of cyclic GMP-AMP synthase (cGAS), Z-DNA-binding protein 1 (ZBP1), and IFN-β was significantly altered in aged mice after ICH. Taken together, our study indicated that compared to young animals, aged mice exhibit increased vulnerability to ICH and that the differences in transcriptional response patterns to ICH between young and aged mice. We believe that these findings will facilitate our understanding of ICH pathology and help to translate the results of preclinical studies into a clinical setting.

LINC00483 promotes proliferation and metastasis through the miR-19a-3p/TBK1/MAPK axis in pancreatic ductal adenocarcinoma (PDAC)

Background

Long noncoding RNAs (lncRNAs) have been found to promote tumor progression. However, the role of lncRNAs in pancreatic ductal adenocarcinoma (PDAC) requires more investigation.

Methods

In this study, microarray was used to measure lncRNA levels in 3 pairs of PDAC tissues. As the highest upregulated lncRNA, LINC00483 was selected for further investigation to determine its functions in PDAC. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to confirm LINC00483 level in PDAC. PDAC cell lines were transfected with short hairpin RNA (shRNA) or microRNA (miRNA). 5-ethynyl-2'-deoxyuridine (EdU) assay, colony formation assay, wound healing assay, transwell assay, and xenograft mouse models were used to evaluate LINC00483 inhibition in vitro and in vivo. Luciferase reporter assay was performed to confirm binding sites of LINC00483 with miR-19a-3p, and miR-19a-3p with TANK-binding kinase 1 (TBK1). Immunohistochemistry (IHC) was performed to evaluate TBK1 and c-myc expression in PDAC tissues. Western blot was used to elucidate the LINC00483/miR-19a-3p/TBK1/mitogen-activated protein kinase (MAPK) axis.

Results

Our data showed that LINC00483 was significantly upregulated in PDAC compared to normal tissue. High level of LINC00483 was correlated with advanced clinical stage, tumor invasion and metastasis, and adverse prognosis in PDAC patients. LINC00483 suppression inhibited proliferation and invasion in vitro and tumor development in vivo via modulation of miR-19a-3p expression. Subsequently, we found that miR-19a-3p binds to TBK1 in PDAC and LINC00483 could regulate PDAC cell progression by regulating miR-19a-3p via the TBK1/MAPK pathway.

Conclusions

The results of our study suggested that the LINC00483/miR-19a-3p/TBK1/MAPK axis contributed to PDAC progression, which provides a potential therapeutic target for PDAC treatment.

Chromatin-based, in cis and in trans regulatory rewiring underpins distinct oncogenic transcriptomes in multiple myeloma

Multiple myeloma is a genetically heterogeneous cancer of the bone marrow plasma cells (PC). Distinct myeloma transcriptome profiles are primarily driven by myeloma initiating events (MIE) and converge into a mutually exclusive overexpression of the CCND1 and CCND2 oncogenes. Here, with reference to their normal counterparts, we find that myeloma PC enhanced chromatin accessibility combined with paired transcriptome profiling can classify MIE-defined genetic subgroups. Across and within different MM genetic subgroups, we ascribe regulation of genes and pathways critical for myeloma biology to unique or shared, developmentally activated or de novo formed candidate enhancers. Such enhancers co-opt recruitment of existing transcription factors, which although not transcriptionally deregulated per se, organise aberrant gene regulatory networks that help identify myeloma cell dependencies with prognostic impact. Finally, we identify and validate the critical super-enhancer that regulates ectopic expression of CCND2 in a subset of patients with MM and in chronic lymphocytic leukemia.

Despite extensive genetic heterogeneity, nearly half of all multiple myeloma (MM) cases are driven by cyclin D2 (CCND2) over-expression. Here the authors dissect the chromatin landscape of MM to provide insights into the transcriptional regulatory landscape driving MM and divergent transcriptomes corresponding to different MM genetic subtypes.