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When glycobiology meets inflammasome activation: Insights and implications.

BACKGROUND: Glycobiology focuses mainly on the study of glycan structures and their biological functions. Glycans not only provide a basic energy supply through the tricarboxylic acid cycle and glycolysis but also serve as important immune regulators during pathogen invasion and homeostasis maintenance. Inflammasomes are critical multiprotein complexes of the immune system that detect both exogenous pathogenic threats and endogenous danger signals to mediate inflammatory responses. Glycobiology has revealed significant insights into the mechanisms of immune responses, particularly in the context of inflammasome activation. AIM OF REVIEW: This review summarizes the multifaceted relationships between glycobiology and inflammasome activation, highlighting how glycan structures, glycosylation patterns, and glycan-binding proteins influence inflammasome pathways. This review sheds light on novel targets for drug development aimed at modulating inflammatory pathways through the targeting of specific glycan structures. KEY SCIENTIFIC CONCEPTS OF REVIEW: Glycans directly or indirectly provide prime and activation signals for inflammasomes, glycosylation of inflammasome-related proteins by glycan structures modulates inflammasome activation and downstream inflammation, and the interaction between glycans and lectins also provides regulatory signals for inflammasome activation. This intersection of glycobiology and inflammasome activation presents a unique opportunity to elucidate the molecular mechanisms underlying inflammatory responses and their potential therapeutic implications.

Inflammasomes

Cross-talk between NLRP3 and AIM2 inflammasomes in macrophage activation by LPS and titanium ions.

BACKGROUND: Periodontitis and peri-implantitis are chronic inflammatory diseases that contribute to tissue destruction and bone loss. Periodontitis is triggered by pathogenic bacteria, while peri-implantitis also involves metallic particles, which increase the inflammatory response. Both conditions are linked to the activation of inflammasomes, such as NLRP3 and AIM2, which facilitate the release of pro-inflammatory cytokines like IL-1β and IL-18 and induce pyroptosis. This study aims to investigate the activation of NLRP3 and AIM2 inflammasomes in macrophages exposed to bacterial and metallic components, as well as to explore the potential interplay between these two signaling pathways. METHODS: Human THP-1-derived macrophages were treated with bacterial lipopolysaccharide (LPS) and titanium ions to evaluate inflammasome activation. IL-1β secretion, ROS production, mitochondrial DNA release and pyroptosis were assessed. Additionally, macrophages deficient in NLRP3 and AIM2 were used to examine the roles of these inflammasomes in inflammatory responses. RESULTS: LPS and titanium ions synergistically activated NLRP3, resulting in increased IL-1β secretion, ROS production, and pyroptosis. Under these conditions, AIM2 was indirectly activated, as indicated by elevated mitochondrial DNA release. Notably, AIM2 expression was reduced in wild-type macrophages treated with LPS and titanium ions compared to LPS alone, however, in NLRP3-deficient cells, AIM2 expression was increased following LPS and titanium ions treatment. This upregulation of AIM2 in NLRP3-deficient cells was further reduced by ROS inhibition, which decreased mitochondrial DNA release. Additionally, NLRP3 knockout had a more pronounced effect on reducing IL-1β secretion and pyroptosis compared to AIM2 knockout, indicating a greater role of NLRP3 in these inflammatory responses. CONCLUSIONS: This study demonstrates that bacterial and metallic components drive the activation of both NLRP3 and AIM2 inflammasomes in macrophages, highlighting their roles in the inflammatory responses associated with periodontitis and peri-implantitis. The findings reveal a regulatory relationship between NLRP3 and AIM2, where the absence of one inflammasome can enhance the activity of the other. These results provide new insights into the mechanisms underlying inflammasome-mediated inflammation and suggest potential therapeutic targets for managing inflammatory diseases.

NLR Family, Pyrin Domain-Containing 3 Protein

Characterizing the Activity of Inflammasome-Related Genes and Their Association With Oncological Outcomes in Prostate Cancer.

BACKGROUND: Inflammation plays a critical role in cancer cell proliferation; however, the specific role of inflammasomes, multiprotein complexes that regulate inflammation-associated signaling pathways, in prostate cancer (PCa) remains insufficiently explored. This study aims to characterize the expression of inflammasome-related genes in PCa and evaluate their association with clinical outcomes. METHODS: De-identified transcriptome data from the Decipher GRID RP, a cohort of 52,266 radical prostatectomy (RP) samples tested (2016-2024) with the Decipher prostate genomic classifier (Veracyte, San Diego, CA), were retrieved from the GRID registry (NCT02609269). Expression analysis of 34 genes involved in inflammatory pathways was conducted to associate their expression with clinical and genomic variables. Outcomes analyses were conducted on a retrospective cohort of 855 patients treated with RP (META855). RESULTS: Analysis of inflammasome gene expression in the GRID RP cohort revealed that most genes exhibit low baseline expression, whereas HSP90AB1, APP, TXN, and TXNIP demonstrate strong expression signals. Additionally, higher expression of most genes was associated with Gleason Grade Group 4-5 and very high Decipher scores. On survival analysis of the META855 cohort, higher expressions of AIM2 and HSP90AB1 were significantly associated with worse metastasis-free survival. Conversely, both high and low expression levels of NLRP3 were associated with better metastasis-free survival outcomes following RP compared to average expression. On multivariable Cox regression analysis, higher expressions of AIM2 (HR 1.75) and HSP90AB1 (HR 1.60) were significantly associated with shorter time to metastasis following RP. CONCLUSIONS: There is molecular heterogeneity within pro-inflammatory genes among patients with PCa. Our findings showed there is a potential association between the expression levels of certain inflammasomes, such as AIM2, HSP90AB1, and NLRP3, and oncological outcomes following RP.

Aged

An epithelial-immune circuit amplifies inflammasome and IL-6 responses to SARS-CoV-2.

Elevated levels of cytokines IL-1β and IL-6 are associated with severe COVID-19. Investigating the underlying mechanisms, we find that while primary human airway epithelia (HAE) have functional inflammasomes and support SARS-CoV-2 replication, they are not the source of IL-1β released upon infection. In leukocytes, the SARS-CoV-2 E protein upregulates inflammasome gene transcription via TLR2 to prime, but not activate, inflammasomes. SARS-CoV-2-infected HAE supply a second signal, which includes genomic and mitochondrial DNA, to stimulate leukocyte IL-1β release. Nuclease treatment, STING, and caspase-1 inhibition but not NLRP3 inhibition blocked leukocyte IL-1β release. After release, IL-1β stimulates IL-6 secretion from HAE. Therefore, infection alone does not increase IL-1β secretion by either cell type. Rather, bi-directional interactions between the SARS-CoV-2-infected epithelium and immune bystanders stimulates both IL-1β and IL-6, creating a pro-inflammatory cytokine circuit. Consistent with these observations, patient autopsy lungs show elevated myeloid inflammasome gene signatures in severe COVID-19.

Humans

Metabolic ketosis attenuates NLRP3 inflammasome activation and is associated with improvements in hepatic steatosis and liver stiffness in MASLD: a pilot randomized controlled trial.

BACKGROUND: Metabolic dysfunction-associated steatotic liver disease (MASLD) is increasingly recognized as a systemic metabolic-inflammatory disorder in which metabolic stress and innate immune activation, particularly through the NLRP3 inflammasome, contribute to disease progression. Metabolic ketosis, characterized by increased levels of circulating ketone bodies, especially &#x3b2;-hydroxybutyrate, has emerged as a promising strategy to modulate substrate utilization, inflammatory signaling, and hepatic injury. However, clinical evidence integrating molecular, metabolic, and hepatic outcomes remains limited. METHODS: In this pilot randomized controlled trial, 20 participants with newly diagnosed MASLD were randomly assigned to either a 3-month intervention with a daily C8-enriched medium-chain fatty acid formulation (m-CAP; meta-Capridin, providing approximately 20 g/day of C8) or a standardized low-carbohydrate dietary protocol. Metabolic indices, inflammatory mediators, adipokines, and hepatic enzymes were assessed. The expression of key inflammasome components (NLRP3, caspase-1, and ASC) was evaluated in peripheral blood mononuclear cells, and hepatic steatosis and liver stiffness were measured via transient elastography. RESULTS: The C8-enriched intervention was associated with increased circulating &#x3b2;-hydroxybutyrate levels, indicating the achievement of nutritional ketosis. Changes over time were observed in metabolic parameters, including fasting serum glucose (p < 0.05), HOMA-IR (p < 0.05), body fat percentage (p < 0.05), and BMI (p < 0.05). Alterations in inflammatory mediators and adipokine-related outcomes were also observed following the intervention. At the molecular level, changes in inflammasome-related markers were detected, including caspase-1 mRNA expression (p < 0.05) and NLRP3 expression at the transcriptional (p < 0.05) and protein levels (p < 0.01), whereas ASC expression remained unchanged. Changes in hepatic steatosis (p < 0.01) and liver stiffness measurements were observed following the intervention. Given the absence of significant Group &#xd7; Time interactions for several secondary outcomes, these findings should be interpreted as exploratory and hypothesis-generating. CONCLUSIONS: Induction of metabolic ketosis was associated with changes in metabolic, inflammatory, and hepatic parameters in patients with MASLD. The observed associations between ketosis, inflammasome-related markers, and noninvasive liver outcomes warrant further investigation of ketosis-based interventions as adjunctive approaches in MASLD. Larger and longer-term clinical trials are needed to confirm these findings and to determine whether short-term changes in liver stiffness reflect sustained alterations in hepatic status rather than structural fibrosis regression. TRIAL REGISTRATION: Iranian Registry of Clinical Trials (IRCT); Unique identifier: IRCT20170315033086N12; Registration date: 19 September 2024; Registry URL: https://www.irct.ir. IRCT is a primary registry in the WHO Registry Network (https://www.who.int/tools/clinical-trials-registry-platform/network/primary-registries).

Humans

Artificial Intelligence-Driven Multi-Omics Analysis Reveals Hydroxytyrosol Targeting of the TXNIP-NLRP3 Inflammasome Axis in Traumatic Brain Injury.

Traumatic brain injury (TBI) induces secondary neuroinflammation driven by oxidative stress, inflammasome activation, and immune remodeling, yet specific mechanism-guided pharmacological interventions remain limited. This study established an artificial intelligence (AI)-integrated network pharmacology and multi-omics framework to evaluate whether hydroxytyrosol (HT), an olive-derived natural polyphenol, may regulate TBI-related neuroinflammatory targets centered on the TXNIP/NLRP3 inflammasome axis. Starting from the SMILES structure of HT, potential targets were predicted using PharmMapper, SwissTargetPrediction, and the Similarity Ensemble Approach and were standardized to UniProt identifiers. TBI-associated genes were integrated from GeneCards, DisGeNET, OMIM, and the Therapeutic Target Database. The overlapping target set was analyzed using STRING-based protein-protein interaction (PPI) networks, MCODE, CytoHubba, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Public GEO transcriptomic datasets (GSE123831 and GSE104687) were used for cross-platform expression validation, differential expression analysis, and exploratory CIBERSORT-based immune infiltration estimation. Random forest (RF), multilayer perceptron (MLP), graph convolutional network (GCN), graph attention network (GAT), SHAP/LIME explainability analysis, LASSO inflammatory-risk scoring, and two-sample Mendelian randomization (MR) were further applied for target prioritization, immune phenotype mapping, and genetic association analysis. Seventy-three overlapping HT-TBI targets were identified. PPI and topology analyses prioritized TXNIP, NLRP3, CASP1, MAPK1, and TP53 as key hubs enriched in inflammasome activation, oxidative stress, apoptosis, and NOD-like receptor signaling. TXNIP, NLRP3, and CASP1 were consistently upregulated in both TBI transcriptomic datasets. LM22-based immune deconvolution suggested increased pro-inflammatory immune signatures and a positive TXNIP-M1 macrophage association (r&#x202f;=&#x202f;0.63, p < 0.001), which should be interpreted as a transcriptome-derived hypothesis rather than validated murine immune-cell proportions. AI-based models consistently ranked TXNIP/NLRP3 as high-contribution features under internal validation, and removal of these targets reduced model performance. A five-gene inflammatory score achieved an internally evaluated AUC of 0.87, while two-sample MR supported positive genetic associations involving TXNIP expression, TBI risk, NLRP3 and IL-1&#x3b2; expression. Collectively, these findings prioritize the TXNIP/NLRP3/CASP1 module as a computationally supported candidate mechanism through which HT may influence oxidative stress-inflammasome-immune coupling in TBI. This study provides an interpretable drug-target-pathway-phenotype framework and identifies TXNIP, NLRP3, and CASP1 as priority nodes for future experimental validation.

Artificial Intelligence

NLRP3 and AIM2 inflammasomes exacerbate the pathogenic Th17 cell response to eggs of the helminth Schistosoma mansoni.

Infection with the helminth Schistosoma mansoni can cause exacerbated morbidity and mortality via a pathogenic host CD4 T cell-mediated immune response directed against parasite egg antigens, with T helper (Th) 17 cells playing a major role in the development of severe granulomatous hepatic immunopathology. The role of inflammasomes in intensifying disease has been reported; however, neither the types of caspases and inflammasomes involved, nor their impact on the Th17 response are known. Here we show that enhanced egg-induced IL-1&#x3b2; secretion and pyroptotic cell death required both caspase-1 and caspase-8 as well as NLRP3 and AIM2 inflammasome activation. Schistosome genomic DNA activated AIM2, whereas reactive oxygen species, potassium efflux and cathepsin B, were the major activators of NLRP3. NLRP3 and AIM2 deficiency led to a significant reduction in pathogenic Th17 responses, suggesting their crucial and non-redundant role in promoting inflammation. Additionally, we show that NLRP3- and AIM2-induced IL-1&#x3b2; suppressed IL-4 and protective Type I IFN (IFN-I) production, which further enhanced inflammation. IFN-I signaling also curbed inflammasome- mediated IL-1&#x3b2; production suggesting that these two antagonistic pathways shape the severity of disease. Lastly, Gasdermin D (Gsdmd) deficiency resulted in a marked decrease in egg-induced granulomatous inflammation. Our findings establish NLRP3/AIM2-Gsdmd axis as a central inducer of pathogenic Th17 responses which is counteracted by IFN-I pathway in schistosomiasis.

Animals

Restraint of inflammasome-driven cytokine responses through the mRNA stability protein TTP.

Activation of the NLRP3 inflammasome causes extensive disturbance of cellular homeostasis, with Golgi disruption, mitochondrial dysfunction, and changes in intracellular ion concentration occurring rapidly upon stimulation. Given this, it would seem near certain that these changes might also globally affect cellular signaling pathways, yet few, if any, studies have explored this possibility. Here, we combine genomics and phosphoproteomics to identify inhibition of the ERK1/2 MAP kinase signaling cascade upon inflammasome stimulation. This loss of ERK1/2 activity results in rapid inactivation of the mRNA decay-promoting protein tristetraprolin (TTP), with loss of TTP promoting subsequent increased release of cytokines upon pyroptosis. Further, we observe significantly increased levels of TTP expression in patients with inflammatory bowel disease, a disease for which altered cytokine expression is a key driver of pathogenesis. Inflammasome activation thus rapidly inactivates a pathway designed to suppress cytokine release, potentially exacerbating hyperinflammatory states, including those involved in autoinflammatory disease.

Inflammasomes

Streptococcus pyogenes EVs induce the alternative inflammasome via caspase-4/-5 in human monocytes.

The sensing of Gram-negative Extracellular Vesicles (EVs) by the innate immune system has been extensively studied in the past decade. In contrast, recognition of Gram-positive EVs by innate immune cells remains poorly understood. Comparative genome-wide transcriptional analysis in human monocytes uncovered that S. pyogenes EVs induce proinflammatory signatures that are markedly distinct from those of their parental cells. Among the 209 genes exclusively upregulated by EVs, caspase-5 prompted us to study inflammasome signaling pathways in depth. We show that lipoteichoic acid (LTA), a structural component of Gram-positive bacterial membranes present on EVs from S. pyogenes and other Gram-positive species, is sensed by TLR2 which triggers the alternative inflammasome composed of NLRP3 and the inflammatory caspases-4/-5 to mount an IL-1&#x3b2; response without inducing cell death. For S. pyogenes, we identify TLR8 as a sensor to mediate caspase-4/-5-dependent IL-1&#x3b2; secretion. Notably, inflammasome activation by intact bacteria is independent of the global virulence regulator CovS in monocytes. Overall, our study highlights a new role for TLR2 and caspase-4/-5 in the recognition of Gram-positive EVs in human monocytes.

Humans

Expression of intron-containing HIV-1 RNA induces NLRP1 inflammasome activation in myeloid cells.

Despite the success of antiretroviral therapy in suppressing plasma viremia in people living with human immunodeficiency virus type-1 (HIV-1), persistent viral RNA expression in tissue reservoirs is observed and can contribute to HIV-1-induced immunopathology and comorbidities. Infection of long-lived innate immune cells, such as tissue-resident macrophages and microglia may contribute to persistent viral RNA production and chronic inflammation. We recently reported that de novo cytoplasmic expression of HIV-1 intron-containing RNA (icRNA) in macrophages and microglia leads to MDA5 and MAVS-dependent innate immune sensing and induction of type I IFN responses, demonstrating that HIV icRNA is a pathogen-associated molecular pattern (PAMP). In this report, we show that cytoplasmic expression of HIV-1 icRNA also induces NLRP1 inflammasome activation and IL-1&#x3b2; secretion in macrophages and microglia in an RLR- and endosomal TLR-independent manner. Infection of both macrophages and microglia with either replication-competent or single-cycle HIV-1 induced IL-1&#x3b2; secretion, which was attenuated when cytoplasmic expression of viral icRNA was prevented. While IL-1&#x3b2; secretion was blocked by treatment with caspase-1 inhibitors or knockdown of NLRP1 or caspase-1 expression in HIV-infected macrophages, overexpression of NLRP1 significantly enhanced IL-1&#x3b2; secretion in an HIV-icRNA-dependent manner. Immunoprecipitation analysis revealed interaction of HIV-1 icRNA, but not multiply-spliced HIV-1 RNA, with NLRP1, suggesting that HIV-1 icRNA sensing by NLRP1 is sufficient to trigger inflammasome activation. Together, these findings reveal a pathway of NLRP1 inflammasome activation induced by de novo expressed HIV icRNA in HIV-infected myeloid cells.

HIV-1

Host Genetic Regulation of NLRP3 Inflammasome Cytokines Reveals Immune and Vascular Pathways in HIV.

People with HIV exhibit elevated inflammation and cardiovascular risk despite antiretroviral therapy. To define the genetic architecture of inflammasome-associated inflammation, we performed whole-genome sequencing and quantified plasma IL-6, IL-1&#x3b2;, and IL-18 in 1,000 ART-suppressed PWH from the U.S. Military HIV Natural History Study. Genome-wide analyses identified 14 loci implicating antiviral defense (DDX17, DDX41, EEA1, BCL11A), lipid metabolism (ABCA1, ABCA12, ABCC1, AGMO), and vascular remodeling (KLHL29, RNF213, ETV1). Transcriptome-wide analyses across cardiovascular and immune tissues identified regulatory programs linking interferon signaling, immune activation, and vascular biology to circulating cytokine levels. Mendelian randomization analyses supported causal relationships between inflammasome-associated cytokines and vascular events. Functional integration with genome-wide CRISPR perturbation datasets in primary CD4+ T cells linked cytokine-associated loci to HIV antiviral pathways and cytokine regulatory networks. External validation in cohorts without HIV demonstrated pathway-level convergence despite limited variant-level overlap. These findings define genetic mechanisms linking inflammasome signaling, antiviral defense, and cardiovascular risk.

HIV

Inflammasome activation dictates the efficacy of antimycobacterial activity of frontline TB drugs.

Recent developments in tuberculosis (TB) treatment have identified an enormous potential of host-directed therapies (HDT)) in achieving better and faster control of infection. We have previously demonstrated the synergistic effect of sertraline (SRT) with frontline TB drugs in clearing infection in murine tissues. Our attempts to uncover the mechanistic basis of this enhancement, using sertraline as a probe, help identify host signalling pathways critical for controlling Mycobacterium tuberculosis (Mtb). We identify a significant role for sertraline-mediated modulation of mitochondrial physiology and consequent reactive oxygen species (ROS) generation as a secondary signal, leading to greater IL-1&#x3b2; release and K+ efflux from macrophages via NLRP3 inflammasome activation. We thus highlight an important relationship between mitochondrial physiology and inflammasome activation, enabling infected macrophages to better control Mtb.

Animals

Trichomonas vaginalis extracellular vesicles activate the NLRP3 inflammasome and TLR3-mediated inflammatory cascades in host cells.

Trichomonas vaginalis (TV) is a flagellated parasite that causes trichomoniasis, the most common non-viral sexually transmitted infection (STI), with over 275 million cases annually. TV has been shown to secrete extracellular vesicles (TV-EVs) to regulate intercellular communication between parasites and host immune response; however, the mechanisms by innate immunity against TV-EVs are largely unknown. Herein, we aim to investigate the molecular mechanisms of inflammation induced by TV-EVs and identify novel proteins modulating the immune response in host cells. Firstly, the morphological characteristics of TV-EVs have been analyzed by transmission electron microscope (TEM) and nanoparticle tracking analysis, revealing that the vesicles are round-shaped bilayer membrane structures with size mostly about 100-120&#x2009;nm. Additionally, the internalization of TV-EVs by host cells has been validated through immunofluorescence and TEM analysis. The multiplex immunoassay identified that TV-EVs induce the secretion of inflammatory cytokines, including CXCL1, IL-6, IL-8 and MIP-1&#x3b2; in THP-1 macrophages and ectocervical cells (Ect). Mechanistically, TV-EVs induce TLR3 overexpression to activate the NF-&#x3ba;B/NLRP3 pathway in THP-1 macrophages. Additionally, TV-EVs activate the PI3K-mediated NF-&#x3ba;B, p38 MAPK and ERK pathways in Ect. Moreover, TV-EV-induced TLR3 overexpression positively regulates the PI3K and NF-&#x3ba;B pathways, while simultaneously suppressing the p38 MAPK and ERK pathways in Ect. Proteomic analysis identified that TV-EVs upregulate MICB and TRAF3IP2, which are also positively regulated by TLR3 and involved in TV-EV-induced inflammatory cascade. Altogether, this study significantly advances our understanding of the immunomodulatory roles of TV-EVs in host cells, paving the way for future treatment of trichomoniasis and TV-associated STIs.

Humans

Targeted Epigenetic Silencing of Jumonji Domain-Containing Protein 3 Alleviates Nuclear Factor-Kappa B-Mediated Inflammation in Familial Mediterranean Fever.

BACKGROUND: Familial Mediterranean fever (FMF) is an inherited autoinflammatory condition caused by variants in the MEFV gene encoding pyrin, the essential component of the NLRP3/NF-&#x3ba;B complex of inflammasomes. Deregulation of nuclear factor-kappa B (NF-&#x3ba;B), a key proinflammatory mediator, leads to chronic inflammation in autoinflammatory/autoimmune diseases. Epigenetic modulation offers a new approach to regulate inflammasome activity, with Jumonji domain-containing protein 3 (JMJD3) being a promising target for managing inflammatory illnesses. GSK-J4 is a selective inhibitor of JMJD3, restricting pro-inflammatory cytokines and inflammation. AIM: Our research aimed to elucidate the role of JMJD3 and the NF-&#x3ba;B-JMJD3 signaling pathways in regulating inflammation in an in vitro model, and to investigate GSK-J4's effect in inhibiting inflammasome activation in primed peripheral blood mononuclear cells (PBMCs) isolated from FMF cases. METHODS: PBMCs were cultured and primed with LPS, and then treated with GSK-J4. JMJD3 knockdown was achieved using siRNA interference. Cellular inflammatory dynamics were assessed by Western blotting (WB) and ELISA. The qRT-PCR was used for gene expression quantification. Untreated cells served as a negative control. RESULTS: Our results showed significantly downregulated gene expression of NF-&#x3ba;B, NLRP3, and inflammatory cytokines in GSK-J4-treated cells compared to untreated cells, as confirmed by ELISA. WB reported a reduction of NF-&#x3ba;B in induced cells following GSK-J4 treatment. Knocking down JMJD3 also showed decreased levels of JMJD3, NF-&#x3ba;B, and inflammatory cytokines, indicating its proinflammatory role. CONCLUSION: The study showed that selective inhibition or silencing of JMJD3 significantly suppressed the inflammasome in FMF cases, suggesting its role as a therapeutic target for alleviating inflammation in various autoinflammatory diseases.

Humans

miR-197 Targets NLRP3 3' UTR and Correlates with NLRP3/Caspase-1/IL-18 Signaling in Hyperoxia-Stimulated Neonatal BPD Mouse Model.

Reduced circulating miR-197 was previously observed in preterm infants who later developed bronchopulmonary dysplasia (BPD), but its relationship with NLRP3 inflammasome signaling remains unclear. This study examined miR-197 expression, NLRP3 inflammasome-related markers, and the interaction between miR-197 and the NLRP3 3' UTR in a neonatal hyperoxia model. Neonatal C57BL/6J mice were exposed to 60% oxygen or room air from birth, and lung tissues were collected on postnatal days 1, 7, 14, and 21. Lung injury and alveolar development were assessed by histology, radial alveolar count, mean linear intercept, and lung wet-to-dry ratio. miR-197 and NLRP3 expression and NF-&#x3ba;B-, caspase-1-, and IL-18-related proteins were evaluated by RT-qPCR and Western blotting. A dual-luciferase reporter assay in MLE12 cells tested the interaction between miR-197 and the NLRP3 3' UTR. Hyperoxia increased lung wet-to-dry ratios and mean linear intercept, reduced radial alveolar count, and caused progressive alveolar simplification. miR-197 expression decreased, whereas NLRP3 mRNA increased, at all examined time points; NLRP3 protein and inflammasome-related protein changes were most evident from postnatal day 7 onward. The miR-197 mimic reduced luciferase activity in the wild-type but not mutant NLRP3 3' UTR reporter. These findings show that neonatal hyperoxia is associated with reduced miR-197 and increased NLRP3/inflammasome-related signaling and support a sequence-specific interaction between miR-197 and the NLRP3 3' UTR, although causal regulation in vivo requires further investigation.

Animals

APOM-associated inflammation and apoptosis in stroke-exacerbated myocardial infarction: implications for brain-heart interactions.

Brain-heart syndrome (BHS) describes cardiac dysfunction secondary to central nervous system injury, with acute ischemic stroke (AIS) serving as a critical driver that exacerbates myocardial infarction (MI). This study aimed to elucidate the role of Apolipoprotein M (APOM) in stroke-aggravated MI and to explore its underlying systemic and molecular mechanisms. Clinical data were analyzed to evaluate the correlation between stroke and MI. A combined mouse model of middle cerebral artery occlusion (MCAO) and MI was established to assess neurological and cardiac injury. Quantitative proteomics and Weighted Gene Co-expression Network Analysis (WGCNA) were employed to screen key differentially expressed proteins. The role of APOM in myocardial injury was validated using APOM-knockout (KO) mice. Furthermore, nuclear-cytoplasmic fractionation, immunofluorescence, and Western blot were performed to investigate its effects on the Saa1 and NF-&#x3ba;B signaling, NLRP3-related inflammatory signaling pathway, and lipid metabolism pathways. Clinical analysis indicated that stroke is a significant risk factor for MI (OR&#x2009;=&#x2009;4.5). In the mouse model, MCAO significantly exacerbated post-MI electrocardiographic abnormalities, myocardial inflammatory response, while elevating circulating levels of cTnT and IL-1&#x3b2;. Proteomics identified a significant downregulation of APOM in the heart, brain, and serum post-stroke, a trend consistent with observations in AIS patients. Further experiments revealed that APOM deficiency markedly worsened cardiac conduction disturbances, histological damage, and inflammatory responses in MI mice. Mechanistically, the loss of APOM upregulates the acute-phase protein Saa1, triggers NF-&#x3ba;B phosphorylation and nuclear translocation, and enhances inflammatory signaling related to inflammasomes, while simultaneously mediating cytokine release from cardiomyocytes. Concurrently, APOM deficiency led to a significant decrease in sphingosine-1-phosphate (S1P) and also caused myocardial lipid droplet accumulation and metabolite changes. Additionally, the loss of APOM increased the expression of D-dimer and fibrinogen family proteins. Our findings suggest that APOM is a potential cardioprotective agent post-AIS. Downregulation of APOM may exacerbate myocardial injury after MI by elevating Saa1 expression, activating the NF-&#x3ba;B pathway and the inflammasome-mediated signaling, and inducing lipid metabolic disorders and coagulation-associated alterations. APOM may represent a potential therapeutic target for the intervention of brain-heart syndrome.

Animals

Functional chimeric mRNAs encode proteins in mammalian immunity.

Individual mammalian mRNAs and proteins are typically believed to originate from single genomic loci, with isoform diversity arising through cis-splicing of pre-mRNA. Whether mRNA from distant genes can undergo trans-splicing to generate functionally relevant chimeric transcripts has remained unclear. Here we develop a pipeline combining long-read direct RNA sequencing with non-targeted and targeted validation to identify chimeric transcripts in macrophages. Chromatin conformation capture studies reveal that inflammation induces interchromosomal DNA interactions, positioning parent genes proximally to facilitate the formation of chimeric mRNA. Notably, we identify a protein-coding chimeric mRNA representing a fusion between the pore-forming protein gasdermin D (GSDMD)1,2 and a C-terminal domain translated out of frame from Tmem106a (Gsdmd-Tmem106a) in mice. We show that inflammasome priming upregulates Gsdmd-Tmem106a, with the protein localizing to the plasma membrane. After activation of the inflammasome, GSDMD-TMEM106A directly interacts with canonical GSDMD N termini to accelerate and enhance pore formation and IL-1&#x3b2; release. Finally, we show that GSDMD-TMEM106A balances host defence and immunopathology in vivo: its loss protects against lethal sepsis but compromises antibacterial defence, whereas overexpression enhances host protection while increasing sepsis lethality. We establish that protein-coding chimeric mRNAs formed by regulated transcript fusion events are operative during inflammation and immunity.

Journal Article

Genomic Structural Equation Modeling Identifies a Shared Inflammatory Genetic Dimension Across Inflammatory Arthritis Phenotypes and Biomarkers.

BACKGROUND: Inflammatory arthritis (IA), including rheumatoid arthritis (RA), psoriatic arthritis (PsA) and gout, shares systemic inflammatory features indexed by C-reactive protein (CRP) and interleukin-6 (IL-6), yet the extent of their common genetic basis remains unclear. AIMS: We aimed to delineate the shared genetic architecture across IA phenotypes and inflammatory biomarkers. MATERIALS AND METHODS: We applied genomic structural equation modelling (Genomic SEM) to GWAS summary statistics for RA, PsA, gout, CRP and IL-6, fitted a single common factor, and performed multivariate GWAS followed by fine-mapping, transcriptome-wide association, gene-based analysis, pathway enrichment, and cell-type and spatial mapping. RESULTS: A single common factor was fitted (CFI = 0.990, SRMR = 0.045). The multivariate GWAS identified 56 genome-wide significant SNPs across 10 independent lead loci, including one novel signal. Fine-mapping prioritized high-confidence variants near PTPN22, the CRP gene cluster and a urate-associated locus. Gene-level analyses converged on DCLRE1B, PTPN22, IL6R, NLRP3 and HNF1A, with pathway enrichment implicating inflammasome assembly and metabolic-inflammatory overlap. Cell-type enrichment highlighted myeloid populations, and spatial mapping localized signals to lung, kidney, mucosal epithelium and gastrointestinal tissues. DISCUSSION: These results delineate a shared inflammatory genetic dimension across IA phenotypes and biomarkers, anchored in immune, inflammasome, cytokine-receptor and metabolic pathways. CONCLUSION: Together, these findings provide a valuable framework for prioritizing candidate genes and cellular contexts for future investigation.

TWAS