Activation Of Innate Immune Response Research Articles

IMMU-56. TARGETING NONO IN GLIOMA VIROIMMUNOTHERAPY

Abstract Despite aggressive therapies, the median survival for glioblastoma (GBM) patients remains just 7-months after tumor progression. Oncolytic virotherapy is a promising approach to reprogramming the immunosuppressed microenvironment of GBMs facilitating anti-tumor immunity. Delta-24-RGD is an oncolytic adenovirus that has shown favorable results in phase I/II clinical trials (NCT00805376, NCT03178032 and NCT02798406). However, the immune response of the patient functionally cleared the virus, limiting its anti-cancer efficacy to a subset (~20%) of patients. It is known that Non-POU Domain Containing Octamer Binding (NONO) is overexpressed in gliomas and is associated with poor survival of patients. Using bulk RNA sequencing, we showed that the NONO pathway is upregulated 7 folds during adenoviral infection. These results were confirmed by western blot analyses that showed a significant increase in the expression of NONO after Delta-24-RGD infection. We detected cellular and viral members of the NONO interactome using mass spectrometry analyses. Immunoprecipitation assays confirmed those results and showed that NONO binds to adenoviral proteins during infection and associates with the foreign DNA sensor cyclic GMP AMP synthase (cGAS). Using shRNA knockdown, we showed that NONO was required to induce innate immune activation in response to adenovirus infection. Thus, we observed a 180-fold increase in type I interferon after the infection with the virus that was reversed in NONO-null cells. Therefore, NONO is a previously undetected innate immune sensor of adenoviruses in the nucleus. In addition, the fact that NONO binds adenoviral proteins suggests a new double-sensor mechanism involving the detection of both foreign DNA and viral proteins. Interactions between NONO and adenoviral proteins should be considered when designing the next generation of oncolytic adenovirus for the treatment of gliomas.

EXTH-81. RE-EXPRESSION OF CXCL9 FOLLOWING ADENO-ASSOCIATED VIRUS (AAV) TRANSGENE DELIVERY TRANSFORMS THE IMMUNOLOGICAL LANDSCAPE OF GLIOBLASTOMA, SENSITIZING TUMORS TO PD-1 IMMUNE CHECKPOINT BLOCKADE (ICB)

Abstract BACKGROUND To date, few glioblastoma (GBM) patients have demonstrated clinical benefit from treatment with anti-PD-1 ICB. GBM is notoriously devoid of lymphocytes, signifying that a possible obstacle for effective ICB response may be the limited ability of cytotoxic T-lymphocytes (CTLs) to home to these tumors. CTLs are recruited via long-range signaling mediated by the diffusion of chemokines present in inflammatory environments. Following a comprehensive chemokine screen of clinical tumor specimens, we identified that CXC motif ligand 9 (CXCL9) is notably absent in GBM. To test if GBM reconstitution with CXCL9 could transform these intractable tumors into ICB-responsive, we leveraged AAV gene therapy to generate durable production of this potent lymphotactic signal. HYPOTHESIS AAV mediated re-expression of CXCL9 will improve lymphotaxis in GBM, sensitizing these tumors to PD-1 ICB. METHODS 3-dimensional whole brain fluorescent imaging was performed to characterize the distribution, tropism, and durability of AAV transgene expression in preclinical GBM models. Single-cell RNA sequencing (scRNAseq) and multiparameter flow cytometry was utilized to immunologically profile tumors in response to single and combination treatment. Survival studies with and without lymphocyte depletion were performed to evaluate immunogenic responsiveness of therapy. RESULTS Intra-tumor delivery of AAV6 yields stable transduction of tumor-reactive astrocytes, producing a localized, peri-tumoral pattern of transgene signal distribution. Combination therapy increases tumor infiltration by lymphocytes. scRNAseq analyses reveal widespread innate and adaptive immune activation in response to each CXCL9 and PD-1 ICB treatment. Infiltrating CD8 T-lymphocytes demonstrate inflammatory signatures associated with increased effector function, including antigen presentation, cytotoxicity, and TCR signaling. Combination treatment considerably improved overall survival in two distinct GBM models, with durable responses dependent on CD8 T-lymphocyte infiltration. CONCLUSIONS This work suggests direct conditioning of the tumor microenvironment by AAV-CXCL9 could potentially overcome a key resistance factor in GBM, sensitizing tumors to immune mediated therapies such as PD-1 ICB.

Single-cell transcriptomics of human traumatic brain injury reveals activation of endogenous retroviruses in oligodendroglia

Traumatic brain injury (TBI) is a leading cause of chronic brain impairment and results in a robust, but poorly understood, neuroinflammatory response that contributes to the long-term pathology. We used single-nuclei RNA sequencing (snRNA-seq) to study transcriptomic changes in different cell populations in human brain tissue obtained acutely after severe, life-threatening TBI. This revealed a unique transcriptional response in oligodendrocyte precursors and mature oligodendrocytes, including the activation of a robust innate immune response, indicating an important role for oligodendroglia in the initiation of neuroinflammation. The activation of an innate immune response correlated with transcriptional upregulation of endogenous retroviruses in oligodendroglia. This observation was causally linked invitro using human glial progenitors, implicating these ancient viral sequences in human neuroinflammation. In summary, this work provides insight into the initiating events of the neuroinflammatory response in TBI, which has therapeutic implications.

Toll-Like Receptor (TLR) 1, 2, and 6 Gene Polymorphisms Support Evidence of Innate Immune Factors in Schizophrenia.

Schizophrenia is a complex psychiatric disorder with an important genetic contribution. Immunological abnormalities have been reported in schizophrenia. Toll-like receptor (TLR) genes play an important role in the activation of the innate immune response, which may help to explain the presence of inflammation in people with this disorder. The aim of this study was to analyze the association of TLR1, TLR2, and TLR6 gene polymorphisms in the etiology of schizophrenia. We included 582 patients with schizophrenia and 525 healthy controls. Genetic analysis was performed using allelic discrimination with TaqMan probes. We observed significant differences between patients and controls in the genotype and allele frequencies of TLR1/rs4833093 (χ2 = 17.3, p = 0.0002; χ2 = 15.9, p = 0.0001, respectively) and TLR2/rs5743709 (χ2 = 29.5, p = 0.00001; χ2 = 7.785, p = 0.0053, respectively), and in the allele frequencies of TLR6/rs3775073 (χ2 = 31.1, p = 0.00001). Finally, we found an interaction between the TLR1/rs4833093 and TLR2/rs5743709 genes, which increased the risk of developing schizophrenia (OR = 2.29, 95% CI [1.75, 3.01]). Our findings add to the evidence suggesting that the activation of innate immune response might play an important role in the development of schizophrenia.

The early life immune dynamics and cellular drivers at single-cell resolution in lamb forestomachs and abomasum

BackgroundFour-chambered stomach including the forestomachs (rumen, reticulum, and omasum) and abomasum allows ruminants convert plant fiber into high-quality animal products. The early development of this four-chambered stomach is crucial for the health and well-being of young ruminants, especially the immune development. However, the dynamics of immune development are poorly understood.ResultsWe investigated the early gene expression patterns across the four-chambered stomach in Hu sheep, at 5, 10, 15, and 25 days of age. We found that forestomachs share similar gene expression patterns, all four stomachs underwent widespread activation of both innate and adaptive immune responses from d 5 to 25, whereas the metabolic function were significantly downregulated with age. We constructed a cell landscape of the four-chambered stomach using single-cell sequencing. Integrating transcriptomic and single-cell transcriptomic analyses revealed that the immune-associated module hub genes were highly expressed in T cells, monocytes and macrophages, as well as the defense-associated module hub genes were highly expressed in endothelial cells in the four-stomach tissues. Moreover, the non-immune cells such as epithelial cells play key roles in immune maturation. Cell communication analysis predicted that in addition to immune cells, non-immune cells recruit immune cells through macrophage migration inhibitory factor signaling in the forestomachs.ConclusionsOur results demonstrate that the immune and defense responses of four stomachs are quickly developing with age in lamb's early life. We also identified the gene expression patterns and functional cells associated with immune development. Additionally, we identified some key receptors and signaling involved in immune regulation. These results help to understand the early life immune development at single-cell resolution, which has implications to develop nutritional manipulation and health management strategies based on specific targets including key receptors and signaling pathways.

A novel C-type lectin (SpccCTL) suppresses MCRV replication by binding viral protein and regulating antiviral peptides in Scylla paramamosain

Pattern recognition receptors (PRRs) play a crucial role in the recognition and activation of innate immune responses against invading microorganisms. This study characterizes a novel C-type lectin (CTL), SpccCTL. The cDNA sequence of SpccCTL has a full length of 1744 bp encoding a 338-amino acid protein. The predicted protein contains a signal peptide, a coiled-coil (CC) domain, and a CLECT domain. It shares more than 50 % similarity with a few CTLs with a CC domain in crustaceans. SpccCTL is highly expressed in gills and hemocytes and upregulated after MCRV challenge, suggesting that it may be involved in antiviral immunity. Recombinant SpccCTL (rSpccCTL) as well as two capsid proteins of MCRV (VP11 and VP12) were prepared. Pre-incubating MCRV virions with rSpccCTL significantly suppresses the proliferation of MCRV in mud crabs, compared with the control (treatment with GST protein), and the survival rate of mud crabs is also significantly decreased. Knockdown of SpccCTL significantly facilitates the proliferation of MCRV in mud crabs. These results reveal that SpccCTL plays an important role in antiviral immune response. GST pull-down assay result shows that rSpccCTL interacts specifically with VP11, but not to VP12. This result is further confirmed by a Co-IP assay. In addition, we found that silencing SpccCTL significantly inhibits the expression of four antimicrobial peptides (AMPs). Considering that these AMPs are members of anti-lipopolysaccharide factor family with potential antiviral activity, they are likely involved in immune defense against MCRV. Taken together, these findings clearly demonstrate that SpccCTL can recognize MCRV by binding viral capsid protein VP11 and regulate the expression of certain AMPs, suggesting that SpccCTL may function as a potential PRR playing an essential role in anti-MCRV immunity of mud crab. This study provides new insights into the antiviral immunity of crustaceans and the multifunctional characteristics of CTLs.

Plant immune receptors interact with hemibiotrophic pathogens to activate plant immunity.

Phytopathogens pose a devastating threat to the productivity and yield of crops by causing destructive plant diseases in natural and agricultural environments. Hemibiotrophic pathogens have a variable-length biotrophic phase before turning to necrosis and are among the most invasive plant pathogens. Plant resistance to hemibiotrophic pathogens relies mainly on the activation of innate immune responses. These responses are typically initiated after the plant plasma membrane and various plant immune receptors detect immunogenic signals associated with pathogen infection. Hemibiotrophic pathogens evade pathogen-triggered immunity by masking themselves in an arms race while also enhancing or manipulating other receptors to promote virulence. However, our understanding of plant immune defenses against hemibiotrophic pathogens is highly limited due to the intricate infection mechanisms. In this review, we summarize the strategies that different hemibiotrophic pathogens interact with host immune receptors to activate plant immunity. We also discuss the significant role of the plasma membrane in plant immune responses, as well as the current obstacles and potential future research directions in this field. This will enable a more comprehensive understanding of the pathogenicity of hemibiotrophic pathogens and how distinct plant immune receptors oppose them, delivering valuable data for the prevention and management of plant diseases.

Dietary β-glucan ameliorates metabolic stress caused by a high dietary carbohydrate level in Nile tilapia

Carbohydrates are an excellent cost-friendly energy source for fish, and they have been used to improve growth performance and reduce dietary protein levels. However, the aquaculture industry has frequently overused high dietary carbohydrate levels, which has caused metabolic disturbances in fish. This deleterious effect is often diagnosed at the end of the production cycle, affects fish health and causes significant losses to farmers. In this context, β-glucan, which is broadly known as an immunomodulator, may ameliorate the deleterious effects caused by high levels of dietary carbohydrates. Therefore, we investigated the effect of dietary β-glucan on the reduction of metabolic disturbances in Nile tilapia fed a high carbohydrate diet. A total of 352 juvenile Nile tilapias (25.39 ± 0.83 g) were fed isoproteic (280 g kg−1 PD) and isoenergetic diets (3130 kcal kg−1) containing low amounts of carbohydrates (CHO-L 270 g kg−1) or high amounts of carbohydrates (CHO-H 620 g kg−1) with four levels of β-glucan (βG; 0, 1, 3 and 6 g kg−1) for 10 weeks. We evaluated the productive performance, plasma glucose, serum triglycerides, hepatosomatic index, total liver and muscle lipid, hepatic glycogen, hepatic activity of hexokinase, glucokinase, pyruvate kinase, glucose-6-phosphate dehydrogenase, malic enzyme, liver histopathology and innate immune responses. Fish fed a high carbohydrate diet had significantly increased productive performance and lipogenesis, presenting higher hepatosomatic indexes, triglycerides, hepatic glycogen, muscular lipid, hepatic activity of glucose-6-dehydrogenase phosphate, and malic enzyme. Additionally, histological analyses indicated expressive cytoplasm vacuolization. The innate immune responses such as leukocyte respiratory activity, complement and lysozyme were also significantly decreased for the high carbohydrate diet, indicating the occurrence of immunosuppression in fish. These results also indicate impaired metabolic functioning. However, β-glucan ameliorated metabolic stress. Specifically, we found a significant decrease in the serum levels of triglycerides, hepatosomatic index, muscular lipid, and hepatic activities of malic and glucose-6-dehydrogenase phosphate enzymes in fish fed high amounts of carbohydrates containing glucan. There was also a significant decrease in hepatic activity of the glycolytic pathway, hexokinase and pyruvate kinase. Moreover, β-glucan modulated the respiratory activity of leukocytes and complement, confirming its immunomodulating effect on fish. In conclusion, β-glucan mitigated the metabolic disturbances caused by the high levels of carbohydrates in the diet of Nile tilapia. This finding indicates that besides having an immunomodulating effect, β-glucan also has metabolic functions/benefits such as reducing glycolysis and lipogenesis.

Emerging Insights into Molecular Mechanisms of Inflammation in Myelodysplastic Syndromes.

Inflammation impacts human hematopoiesis across physiologic and pathologic conditions, as signals derived from the bone marrow microenvironment, such as pro-inflammatory cytokines and chemokines, have been shown to alter hematopoietic stem cell (HSCs) homeostasis. Dysregulated inflammation can skew HSC fate-related decisions, leading to aberrant hematopoiesis and potentially contributing to the pathogenesis of hematological disorders such as myelodysplastic syndromes (MDS). Recently, emerging studies have used single-cell sequencing and muti-omic approaches to investigate HSC cellular heterogeneity and gene expression in normal hematopoiesis as well as in myeloid malignancies. This review summarizes recent reports mechanistically dissecting the role of inflammatory signaling and innate immune response activation due to MDS progression. Furthermore, we highlight the growing importance of using multi-omic techniques, such as single-cell profiling and deconvolution methods, to unravel MDSs' heterogeneity. These approaches have provided valuable insights into the patterns of clonal evolution that drive MDS progression and have elucidated the impact of inflammation on the composition of the bone marrow immune microenvironment in MDS.

Betacoronaviruses SARS-CoV-2 and HCoV-OC43 infections in IGROV-1 cell line require aryl hydrocarbon receptor

ABSTRACT The emergence of novel betacoronaviruses has posed significant financial and human health burdens, necessitating the development of appropriate tools to combat future outbreaks. In this study, we have characterized a human cell line, IGROV-1, as a robust tool to detect, propagate, and titrate betacoronaviruses SARS-CoV-2 and HCoV-OC43. IGROV-1 cells can be used for serological assays, antiviral drug testing, and isolating SARS-CoV-2 variants from patient samples. Using time-course transcriptomics, we confirmed that IGROV-1 cells exhibit a robust innate immune response upon SARS-CoV-2 infection, recapitulating the response previously observed in primary human nasal epithelial cells. We performed genome-wide CRISPR knockout genetic screens in IGROV-1 cells and identified Aryl hydrocarbon receptor (AHR) as a critical host dependency factor for both SARS-CoV-2 and HCoV-OC43. Using DiMNF, a small molecule inhibitor of AHR, we observed that the drug selectively inhibits HCoV-OC43 infection but not SARS-CoV-2. Transcriptomic analysis in primary normal human bronchial epithelial cells revealed that DiMNF blocks HCoV-OC43 infection via basal activation of innate immune responses. Our findings highlight the potential of IGROV-1 cells as a valuable diagnostic and research tool to combat betacoronavirus diseases.

Targeting DNA Damage Repair and Immune Checkpoint Proteins for Optimizing the Treatment of Endometrial Cancer.

The dependence of cancer cells on the DNA damage response (DDR) pathway for the repair of endogenous- or exogenous-factor-induced DNA damage has been extensively studied in various cancer types, including endometrial cancer (EC). Targeting one or more DNA damage repair protein with small molecules has shown encouraging treatment efficacy in preclinical and clinical models. However, the genes coding for DDR factors are rarely mutated in EC, limiting the utility of DDR inhibitors in this disease. In the current review, we recapitulate the functional role of the DNA repair system in the development and progression of cancer. Importantly, we discuss strategies that target DDR proteins, including PARP, CHK1 and WEE1, as monotherapies or in combination with cytotoxic agents in the treatment of EC and highlight the compounds currently being evaluated for their efficacy in EC in clinic. Recent studies indicate that the application of DNA damage agents in cancer cells leads to the activation of innate and adaptive immune responses; targeting immune checkpoint proteins could overcome the immune suppressive environment in tumors. We further summarize recently revolutionized immunotherapies that have been completed or are now being evaluated for their efficacy in advanced EC and propose future directions for the development of DDR-based cancer therapeutics in the treatment of EC.

Anti-Migratory and Cytotoxic Activities of [Ga(8-hydroxyquinolinato)3 ]: Roles of Endogenous Cu(II) and Drug-Induced Phenotypic Changes.

As shown by IncuCyte Zoom imaging proliferation assays, invasive triple-negative human breast MDA-MB-231 cancer cells treated with sub-toxic doses (5.0-20 μM, 72 h) of [GaQ3 ] (Q=8-hydroxyquinolinato) caused profound morphological changes and inhibition of cell migration, which were likely due to terminal cell differentiation or similar phenotypical change. This is the first demonstration of potential use of a metal complex in differentiation anti-cancer therapy. Additionally, a trace amount of Cu(II) (0.20 μM) added to the medium dramatically increased [GaQ3 ] cytotoxicity (IC50 ~2 μM, 72 h) due to its partial dissociation and the action of the HQ ligand as a Cu(II) ionophore, as shown with electrospray mass spectrometry and fluorescence spectroscopy assays in the medium. Hence, cytotoxicity of [GaQ3 ] is strongly linked to ligand binding of essential metal ions in the medium, for example, Cu(II). Appropriate delivery mechanisms of such complexes and their ligands could enable a powerful new triple therapeutic approach for cancer chemotherapy, including cytotoxicity against primary tumour, arrest of metastases, and activation of innate and adaptive immune responses.

Evolution oftransient RNA structure-RNA polymerase interactions inrespiratory RNA virus genomes.

RNA viruses are important human pathogens that cause seasonal epidemics and occasional pandemics. Examples are influenza A viruses (IAV) and coronaviruses (CoV). When emerging IAV and CoV spill over to humans, they adapt to evade immune responses and optimize their replication and spread in human cells. In IAV, adaptation occurs in all viral proteins, including the viral ribonucleoprotein (RNP) complex. RNPs consist of a copy of the viral RNA polymerase, a double-helical coil of nucleoprotein, and one of the eight segments of the IAV RNA genome. The RNA segments and their transcripts are partially structured to coordinate the packaging of the viral genome and modulate viral mRNA translation. In addition, RNA structures can affect the efficiency of viral RNA synthesis and the activation of host innate immune response. Here, we investigated if RNA structures that modulate IAV replication processivity, so-called template loops (t-loops), vary during the adaptation of pandemic and emerging IAV to humans. Using cell culture-based replication assays and in silico sequence analyses, we find that the sensitivity of the IAV H3N2 RNA polymerase to t-loops increased between isolates from 1968 and 2017, whereas the total free energy of t-loops in the IAV H3N2 genome was reduced. This reduction is particularly prominent in the PB1 gene. In H1N1 IAV, we find two separate reductions in t-loop free energy, one following the 1918 pandemic and one following the 2009 pandemic. No destabilization of t-loops is observed in the influenza B virus genome, whereas analysis of SARS-CoV-2 isolates reveals destabilization of viral RNA structures. Overall, we propose that a loss of free energy in the RNA genome of emerging respiratory RNA viruses may contribute to the adaption of these viruses to the human population.

Cyclodextrin in Vaccines: Enhancing Efficacy and Stability

Cyclodextrins, a family of cyclic oligosaccharides, have received considerable interest in the field of pharmaceuticals due to their unique molecular structure and versatile properties. In the context of vaccines, cyclodextrins can effectively encapsulate antigens, ensuring their protection from degradation and improving their immunogenicity. Cyclodextrins offer stability advantages to vaccines by preventing the degradation of labile vaccine components during storage and transportation. Furthermore, cyclodextrins can serve as adjuvants, potentiating the immune response triggered by vaccines. Their unique structure and interaction with the immune system enhance the recognition of antigens by immune cells, leading to an improved activation of both innate and adaptive immune responses. This adjuvant effect contributes to the development of robust and long-lasting immune protection against targeted pathogens. Owing to the distinctive attributes inherent to nanoparticles, their integration into vaccine formulations has assumed an imperative role. Through the encapsulation of vaccine antigens/adjuvants within cyclodextrin nanoparticles, the potency and stability of vaccines can be notably enhanced. In particular, the capacity of amphiphilic cyclodextrins to form nanoparticles through self-assembly without surfactants or co-solvents is a captivating prospect for their application as carrier systems for antigens. In conclusion, cyclodextrins present a promising platform for enhancing the efficacy and stability of vaccines. Their ability to encapsulate antigens, stabilize labile vaccine components and act as adjuvants demonstrates their potential to revolutionize vaccine formulation and delivery. Further research and development in this field will facilitate the translation of cyclodextrin-based vaccine technologies into practical and impactful immunization strategies, ultimately benefiting global health and disease prevention.

Modifying immune responses to adeno-associated virus vectors by capsid engineering

De novo immune responses are considered major challenges in gene therapy. With the aim to lower innate immune responses directly in cells targeted by adeno-associated virus (AAV) vectors, we equipped the vector capsid with a peptide known to interfere with Toll-like receptor signaling. Specifically, we genetically inserted in each of the 60 AAV2 capsid subunits the myeloid differentiation primary response 88 (MyD88)-derived peptide RDVLPGT, known to block MyD88 dimerization. Inserting the peptide neither interfered with capsid assembly nor with vector production yield. The novel capsid variant, AAV2.MB453, showed superior transduction efficiency compared to AAV2 in human monocyte-derived dendritic cells and in primary human hepatocyte cultures. In linewith our hypothesis, AAV2.MB453 and AAV2 differed regarding innate immune response activation in primary human cells, particularly for type I interferons. Furthermore, mice treated with AAV2.MB453 showed significantly reduced CD8+ Tcell responses against the transgene product for different administration routes and against the capsid following intramuscular administration. Moreover, humoral responses against the capsid were mitigated as indicated by delayed IgG2a antibody formation and an increased NAb50. To conclude, insertion of the MyD88-derived peptide into the AAV2 capsid improved early steps of host-vector interaction and reduced innate and adaptive immune responses.

Abstract P3062: Tet2 Maintains Genome Stablity In Cardiac Myeloid Cells

Myeloid cells play critical roles in the regulation of myocardial injury and repair. Clonal hematopoiesis (CH)-related mutations in genes, such as Ten-eleven Translocation 2 (TET2), can impair myeloid cells and are associated with increased risk of cardiovascular disease. To identify the subsets of myeloid cells that are impacted by Tet2 loss-of-function (LOF) and illuminate how Tet2 LOF disrupts normal myocardial repair, we analyzed the dynamics of myeloid cells in a myeloid-specific Tet2-deficient mouse model after ischemia-induced myocardial infarction (MI). We observed a substantial increase of neutrophils in the post-MI mice, which contributes to adverse outcomes during heart repair. Mechanistically, Tet2-deficient myeloid cells exhibited increased genome instability, accompanied with augmented activation of the intracellular innate immune response. Furthermore, pharmacological inhibiting intracellular innate immunity resulted in significantly reduced neutrophils in Tet2-deficient mice after MI and reversal of deleterious cardiac outcomes. Findings from this study are consistent with the conclusion that targeting the innate immune pathways is a viable therapeutic option to reduce the risk of cardiovascular diseases in CH individuals bearing TET2 LOF mutations.

NLRP11 is a pattern recognition receptor for bacterial lipopolysaccharide in the cytosol of human macrophages.

Endotoxin-bacterial lipopolysaccharide (LPS)-is a driver of lethal infection sepsis through excessive activation of innate immune responses. When delivered to the cytosol of macrophages, cytosolic LPS (cLPS) induces the assembly of an inflammasome that contains caspases-4/5 in humans or caspase-11 in mice. Whereas activation of all other inflammasomes is triggered by sensing of pathogen products by a specific host cytosolic pattern recognition receptor protein, whether pattern recognition receptors for cLPS exist has remained unclear, because caspase-4, caspase-5, and caspase-11 bind and activate LPS directly in vitro. Here, we show that the primate-specific protein NLRP11 is a pattern recognition receptor for cLPS that is required for efficient activation of the caspase-4 inflammasome in human macrophages. In human macrophages, NLRP11 is required for efficient activation of caspase-4 during infection with intracellular Gram-negative bacteria or upon electroporation of LPS. NLRP11 could bind LPS and separately caspase-4, forming a high-molecular weight complex with caspase-4 in HEK293T cells. NLRP11 is present in humans and other primates but absent in mice, likely explaining why it has been overlooked in screens looking for innate immune signaling molecules, most of which have been carried out in mice. Our results demonstrate that NLRP11 is a component of the caspase-4 inflammasome activation pathway in human macrophages.

Air Pollution and Diet: Potential Interacting Exposures in Asthma.

To provide a review of emerging literature describing the impact of diet on the respiratory response to air pollution in asthma. Asthma phenotyping (observable characteristics) and endotyping (mechanistic pathways) have increased the specificity of diagnostic and treatment pathways and opened the doors to the identification of subphenotypes with enhanced susceptibility to exposures and interventions. Mechanisms underlying the airway immune response to air pollution are still being defined but include oxidative stress, inflammation, and activation of adaptive and innate immune responses, with genetic susceptibility highlighted. Of these, neutrophil recruitment and activation appear prominent; however, understanding neutrophil function in response to pollutant exposures is a research gap. Diet may play a role in asthma pathogenesis and morbidity; therefore, diet modification is a potential target opportunity to protect against pollutant-induced lung injury. In particular, in vivo and in vitro data suggest the potential for diet to modify the inflammatory response in the airways, including impacts on neutrophil recruitment and function. Murine models provide compelling results in regard to the potential for dietary components (including fiber, antioxidants, and omega-3 fatty acids) to buffer against the inflammatory response to air pollution in the lung. Precision lifestyle approaches to asthma management and respiratory protection in the context of air pollution exposures may evolve to include diet, pending the results of further epidemiologic and causal investigation and with neutrophil recruitment and activation as a candidate mechanism.

Identification of the biological processes, immune cell landscape, and hub genes shared by acute anaphylaxis and ST-segment elevation myocardial infarction.

Background: Patients with anaphylaxis are at risk for ST-segment elevation myocardial infarction (STEMI). However, the pathological links between anaphylaxis and STEMI remain unclear. Here, we aimed to explore shared biological processes, immune effector cells, and hub genes of anaphylaxis and STEMI. Methods: Gene expression data for anaphylactic (GSE69063) and STEMI (GSE60993) patients with corresponding healthy controls were pooled from the Gene Expression Omnibus database. Differential expression analysis, enrichment analysis, and CIBERSORT were used to reveal transcriptomic signatures and immune infiltration profiles of anaphylaxis and STEMI, respectively. Based on common differentially expressed genes (DEGs), Gene Ontology analysis, cytoHubba algorithms, and correlation analyses were performed to identify biological processes, hub genes, and hub gene-related immune cells shared by anaphylaxis and STEMI. The robustness of hub genes was assessed in external anaphylactic (GSE47655) and STEMI (GSE61144) datasets. Furthermore, a murine model of anaphylaxis complicated STEMI was established to verify hub gene expressions. The logistic regression analysis was used to evaluate the diagnostic efficiency of hub genes. Results: 265 anaphylaxis-related DEGs were identified, which were associated with immune-inflammatory responses. 237 STEMI-related DEGs were screened, which were involved in innate immune response and myeloid leukocyte activation. M0 macrophages and dendritic cells were markedly higher in both anaphylactic and STEMI samples compared with healthy controls, while CD4+ naïve T cells and CD8+ T cells were significantly lower. Enrichment analysis of 33 common DEGs illustrated shared biological processes of anaphylaxis and STEMI, including cytokine-mediated signaling pathway, response to reactive oxygen species, and positive regulation of defense response. Six hub genes were identified, and their expression levels were positively correlated with M0 macrophage abundance and negatively correlated with CD4+ naïve T cell abundance. In external anaphylactic and STEMI samples, five hub genes (IL1R2, FOS, MMP9, DUSP1, CLEC4D) were confirmed to be markedly upregulated. Moreover, experimentally induced anaphylactic mice developed impaired heart function featuring STEMI and significantly increased expression of the five hub genes. DUSP1 and CLEC4D were screened as blood diagnostic biomarkers of anaphylaxis and STEMI based on the logistic regression analysis. Conclusion: Anaphylaxis and STEMI share the biological processes of inflammation and defense responses. Macrophages, dendritic cells, CD8+ T cells, and CD4+ naïve T cells constitute an immune cell population that acts in both anaphylaxis and STEMI. Hub genes (DUSP1 and CLEC4D) identified here provide candidate genes for diagnosis, prognosis, and therapeutic targeting of STEMI in anaphylactic patients.

Diesel Exhaust Particle (DEP)-induced glucose intolerance is driven by an intestinal innate immune response and NLRP3 activation in mice

BackgroundWe previously found that air pollution particles reaching the gastrointestinal tract elicit gut inflammation as shown by up-regulated gene expression of pro-inflammatory cytokines and monocyte/macrophage markers. This inflammatory response was associated with beta-cell dysfunction and glucose intolerance. So far, it remains unclear whether gut inflammatory changes upon oral air pollution exposure are causally linked to the development of diabetes. Hence, our aim was to assess the role of immune cells in mediating glucose intolerance instigated by orally administered air pollutants.MethodsTo assess immune-mediated mechanisms underlying air pollution-induced glucose intolerance, we administered diesel exhaust particles (DEP; NIST 1650b, 12 µg five days/week) or phosphate-buffered saline (PBS) via gavage for up to 10 months to wild-type mice and mice with genetic or pharmacological depletion of innate or adaptive immune cells. We performed unbiased RNA-sequencing of intestinal macrophages to elucidate signaling pathways that could be pharmacologically targeted and applied an in vitro approach to confirm these pathways.ResultsOral exposure to air pollution particles induced an interferon and inflammatory signature in colon macrophages together with a decrease of CCR2− anti-inflammatory/resident macrophages. Depletion of macrophages, NLRP3 or IL-1β protected mice from air pollution-induced glucose intolerance. On the contrary, Rag2-/- mice lacking adaptive immune cells developed pronounced gut inflammation and glucose intolerance upon oral DEP exposure.ConclusionIn mice, oral exposure to air pollution particles triggers an immune-mediated response in intestinal macrophages that contributes to the development of a diabetes-like phenotype. These findings point towards new pharmacologic targets in diabetes instigated by air pollution particles.