Innate Immune Mechanisms Research Articles

Synovial innate immune exhaustion is associated with worse pain in knee osteoarthritis.

Uncontrolled pain remains a major clinical challenge in the management of knee osteoarthritis (OA), the most common disabling joint disease. Worse pain is associated with synovial innate immune cell infiltration (synovitis), but the role of innate immune regulatory cells in pain is unknown. Our objective was to identify synovial innate immune cell subsets and pathophysiologic mechanisms associated with worse pain in patients with knee OA. Synovial tissue biopsies from 122 patients with mild to severe knee OA pain (Knee injury and OA Outcome Score; KOOS) were analyzed to identify associations between synovial histopathology and worse pain. We then used spatial transcriptomics and proteomics of synovial tissue microenvironments (n=32), followed by single cell RNA sequencing (n=8), to identify synovial cell composition and cell-cell communication networks in patients with more severe OA pain. Histopathological signs of synovial microvascular dysfunction, perivascular edema, were associated with worse KOOS pain (-10.76 [95%CI -18.90, -2.61]). Patients with worse pain had fewer immune-regulatory macrophages, expanded fibroblast subsets, and enrichment in neurovascular remodeling pathways. Synovial macrophages from patients with worse pain expressed markers of immune exhaustion, decreased phagocytic function (-19.42% [95%CI -35.96, -2.89]) and their conditioned media increased neuronal cell stress in dorsal root ganglia. Although synovitis increases during OA, our findings suggest that exhaustion, dysfunction, and loss of immune-regulatory macrophages is associated with worse pain and may be an important therapeutic target.

HSC70 functions as a negatively regulator in IFN signaling pathway via suppressing K63-linked ubiquitination of RIG-I in black carp.

Heat shock cognate 70 (HSC70), a highly conserved molecular chaperone in the heat shock protein 70 (HSP70) family, plays an essential role in maintaining the homeostasis of the cellular environment. Furthermore, although previous studies have investigated potential function of HSC70 in innate antiviral immunity, further research is still required to fully elucidate its role. In this study, we cloned and characterized the HSC70 homolog gene from black carp (Mylopharyngodon piceus), which consists of 1950 nucleotides encoding 650 amino acids, migrates at approximately 71 kDa on SDS-PAGE, and is distributed in the cytoplasm. In response to different stimuli (SVCV, poly (I:C) and LPS), the transcription level of black carp HSC70 (bcHSC70) all increased to a certain extent. Luciferase reporter assay demonstrated that co-transfected bcHSC70 obviously reduced activity of interferon (IFN) promoters mediated by most factors in the RLRs pathway, and further qRT-PCR and plaque assay indicated that co-transfection of bcHSC70 with bcRIG-I decreased the bcRIG-I-mediated IFN transcription and antiviral ability resisting spring viremia of carp virus (SVCV), whereas knockdown of bcHSC70 improves the host cellular antiviral activity. Noteworthily, co-immunoprecipitation (co-IP) assay and immunofluorescence (IF) assay confirmed bcHSC70 interacts with bcRIG-I, and weaken K63-linked polyubiquitination of bcRIG-I. In summary, our study revealed that HSC70 negatively regulates IFN signaling pathway through impairing K63-linked ubiquitination of RIG-I in black carp, which provides an important basis for exploring innate immune regulatory mechanisms in teleost fish.

Role of innate immune receptors in the psoriasis development

Psoriasis is an immune-mediated autoimmune inflammatory skin disease with a prevalence of 2 to 3% worldwide. In the psoriasis development and pathogenesis an important role is played by disorders in the immune system. Disruption of the innate and adaptive immune response mechanisms with the involvement of keratinocytes leads to the initiation and maintenance of inflammation. Immune reactions are activated in the skin, in which various cells participate (macrophages, dendritic cells, mast cells, innate immune lymphoid cells, melanocytes, keratinocytes, Langerhans cells and γδT cells; T and B cells; epithelial endothelial and stromal cells of the skin), each of which expresses pattern recognition receptors that respond to pathogens and cell damage itself. Many of these receptors, in particular toll-like receptors and NOD-like receptors play an important role in the pathogenesis of psoriasis. The associated innate receptors signaling cascades that activate in the skin cells may become potential targets for the treatment of this disease. To date, there are several approved drugs for biological therapy of psoriasis. The study of the role of the innate immune cells receptors in inflammatory skin pathologies requires further exploration and new developments.

Herpes simplex virus-1 targets the 2′-3'cGAMP importer SLC19A1 as an antiviral countermeasure

The extracellular addition of the STING agonist, 2-3cGAMP, induces an antiviral state that inhibits HSV-1 replication in a cell type dependent manner via the transportation of the cyclic-dinucleotide through the folate antiporter SLC19A1. To establish a successful infection, herpes simplex virus-1 (HSV-1), a ubiquitous virus with high seropositivity in the human population, must undermine a multitude of host innate and intrinsic immune defense mechanisms, including key players of the STimulator of INterferon Genes (STING) pathway. Herein, we report that HSV-1 infection results in the reduction of SLC19A1 transcription, translation, and importantly, the rapid removal of SLC19A1 from the cell surface of infected cells. Our data indicate SLC19A1 functions as a newly identified antiviral mediator for extracellular 2′-3'cGAMP which is undermined by HSV-1 protein ICP27. This work presents novel and important findings about how HSV-1 manipulates the host's immune environment for viral replication and discovers details about an important antiviral mechanism.

The protein composition of human adenovirus replication compartments.

Human adenoviruses are double-stranded DNA viruses that replicate in the cell nucleus and induce the formation of replication compartments (RCs) that are critical in viral replication and control of virus-host interactions. RCs are specialized virus-induced subnuclear microenvironments where not only viral genome replication and expression are orchestrated but also host proteins that restrict viral replication are co-opted and subverted. The protein composition of these RCs remains largely unexplored. In this study, we isolated adenovirus RC-enriched fractions from infected cells at different times post-infection and employed a tandem mass tag-based quantitative mass spectrometry approach to identify proteins associated with RCs (data available via ProteomeXchange identifier PXD051745). These findings reveal an elaborate network of host and viral proteins potentially relevant for RC formation and function. To validate the RC-protein components identified by mass spectrometry, we employed immunofluorescence and immunoblotting techniques. Proteins previously described to colocalize in RCs in infected cells were identified in the isolated subnuclear fractions. In addition, we validated newly identified proteins associated with RCs, including the high mobility group box 1 (HMGB1), the SET nuclear proto-oncogene, the structure-specific recognition protein 1 (SSRP1), the CCCTC-binding protein (CTCF), and sirtuin 6 (SIRT6). We identified HMGB1 as a protein that binds to the viral DNA binding protein (DBP). Using shRNA knockdowns and inhibitors, we demonstrated that HMGB1 acts as a proviral factor, promoting efficient viral DNA synthesis and progeny production. Our data further suggest potential candidate targets for therapeutic intervention and provide mechanistic insights into the molecular basis of virus-host interactions.IMPORTANCEHuman adenoviruses serve as models for studying respiratory viruses and have provided critical insights into viral genome replication and gene expression, as well as the control of virus-host interactions. These processes are coordinated within virus-induced subnuclear microenvironments known as RCs. We conducted quantitative proteome analyses of RC-enriched subnuclear fractions at different times post-infection with human adenovirus species C type 5, revealing a multifaceted network of proteins that participate in the regulation of gene expression, DNA damage response, RNA metabolism, innate immunity, and other cellular antiviral defense mechanisms. Furthermore, we validated the localization of several host proteins to viral RCs using immunofluorescence microscopy and immunoblotting and identified cellular HMGB1 as a proviral factor late during infection. These findings represent the first analysis of the proteomes of isolated RCs and not only enhance our understanding of nuclear organization during infection but also shed light on the complex interplay between viral and host factors within RCs.

BCL2 regulates antibacterial autophagy in the intestinal epithelium

Autophagy is a key innate immune defense mechanism in intestinal epithelial cells. Bacterial invasion of epithelial cells activates antibacterial autophagy through a process that requires the innate immune adaptor protein MYD88, yet how MYD88 signaling connects to the autophagy machinery is unknown. Here, we show that the mouse intestinal pathogen Salmonella enterica Serovar Typhimurium (Salmonella Typhimurium) triggers MYD88 signaling that regulates binding of the anti-autophagy factor B cell lymphoma 2 (BCL2) to the essential autophagy protein Beclin1 (BECN1) in small intestinal enterocytes, a key epithelial cell lineage. Salmonella infection activated the kinase c-Jun N-terminal protein kinase 1 (JNK1) downstream of MYD88. JNK1 induced enterocyte BCL2 phosphorylation, promoting dissociation of the inhibitory BCL2-BECN1 complex and releasing BECN1 to initiate autophagy. Mice with BCL2 phosphorylation site mutations that prevent BCL2-BECN1 dissociation showed increased Salmonella invasion of enterocytes and dissemination to extraintestinal sites. These findings reveal that BCL2 links MYD88 signaling to enterocyte autophagy initiation, providing mechanistic insight into how invading bacteria trigger autophagy in the intestinal epithelium.

Cytomegalovirus Biology Viewed Through a Cell Death Suppression Lens

Cytomegaloviruses, species-specific members of the betaherpesviruses, encode an impressive array of immune evasion strategies committed to the manipulation of the host immune system enabling these viruses to remain for life in a stand-off with host innate and adaptive immune mechanisms. Even though they are species-restricted, cytomegaloviruses are distributed across a wide range of different mammalian species in which they cause systemic infection involving many different cell types. Regulated, or programmed cell death has a recognized potential to eliminate infected cells prior to completion of viral replication and release of progeny. Cell death also naturally terminates replication during the final stages of replication. Over the past two decades, the host defense potential of known programmed cell death pathways (apoptosis, necroptosis, and pyroptosis), as well as a novel mitochondrial serine protease pathway have been defined through studies of cytomegalovirus-encoded cell death suppressors. Such virus-encoded inhibitors prevent virus-induced, cytokine-induced, and stress-induced death of infected cells while also moderating inflammation. By evading cell death and consequent inflammation as well as innate and adaptive immune clearance, cytomegaloviruses represent successful pathogens that become a critical disease threat when the host immune system is compromised. This review will discuss cell death programs acquired for mammalian host defense against cytomegaloviruses and enumerate the range of modulatory strategies this type of virus employs to balance host defense in favor of lifelong persistence.

Integrative bioinformatics analysis of immune activation and gene networks in pediatric septic arthritis

BackgroundPediatric septic arthritis, driven by Staphylococcus aureus, leads to substantial morbidity due to the host’s complex inflammatory response. This study integrates bioinformatics analyses to map the genomic and immune profiles of pediatric septic arthritis, aiming to identify key biomarkers and therapeutic targets. MethodsAn integrative bioinformatics approach was adopted to analyze gene expression datasets from the GEO database, focusing on pediatric septic arthritis. DEGs were identified using GEO2R, and gene co-expression networks were generated via GeneMANIA. STRING database and Cytoscape software facilitated PPI network construction. DAVID enabled functional enrichment analysis to elucidate biological processes and pathways, while iRegulon predicted transcription factor regulation. CIBERSORT provided a detailed profile of immune cell alterations in the condition. ResultsFrom the datasets analyzed, 576 DEGs were extracted, with 35 shared between the two datasets, revealing an innate immunity signature with notable hub genes such as MPO and ELANE, indicative of a pronounced neutrophilic response. Functional enrichment analysis highlighted pathways pertinent to antimicrobial defense and NET formation. Key transcription factors, including PBX1, POLR2A, and STAT3, were identified as potential modulators of these pathways. Immune profiling demonstrated significant shifts in cell populations, with increased plasma cells and reduced CD4+ naïve T cells. ConclusionsThis study elucidates the complex genomic and immunological milieu of pediatric septic arthritis, uncovering potential biomarkers and signaling pathways for targeted therapeutic intervention. These findings underscore the preeminence of innate immune mechanisms in the disease's pathology and offer a foundation for future research to explore diagnostic and treatment innovations. Translation of these bioinformatics discoveries into clinical applications requires further validation and consideration of the limitations inherent to gene expression data and its interpretation.

Discovery of NP3-253, a Potent Brain Penetrant Inhibitor of the NLRP3 Inflammasome.

Activation of the NLRP3 inflammasome in response to danger signals is a key innate immune mechanism and results in the production of the pro-inflammatory cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18) as well as pyroptotic cell death. Aberrant NLRP3 activation has been linked to many acute and chronic conditions ranging from atherosclerosis to Alzheimer's disease and cancer, and based on the clinical success of IL-1-targeting therapies, NLRP3 has emerged as an attractive therapeutic target. Herein we describe our discovery, characterization, and structure-based optimization of a pyridazine-based series of NLRP3 inhibitors initiating from an high-throughput screening campaign. The scaffold, exemplified by lead molecule NP3-253, has excellent potency and physicochemical and pharmacokinetic properties, including good brain penetration. The establishment of pharmacokinetic/pharmacodynamic relationships in the periphery and central nervous system in mechanistic models facilitates the use of NP3-253 as a tool to further interrogate the biology of NLRP3 in peripheral and neuroinflammatory models.

NEIL1 block IFN-β production and enhance vRNP function to facilitate influenza A virus proliferation

Influenza A virus (IAV) has developed multiple tactics to hinder the innate immune response including the epigenetic regulation during IAV infection, but the novel epigenetic factors and their mechanism in innate immunity remain well studied. Here, through a non-biased high-throughput sgRNA screening of 1041 known epigenetic modifiers in a cellular model of IAV-induced interferon-beta (IFN-β) production, we identified nei endonuclease VIII-like 1 (NEIL1) as a critical regulator of IFN-β in response to viral infection. Further studies showed that NEIL1 promoted the replication of the influenza virus by regulating the methylation of cytonuclear IFN-β promoter (mainly CpG-345), inhibiting the expression of IFN-β and IFN-stimulating genes. The structural domains of NEIL1, especially the catalytic domain, were critical for the suppression of IFN-β production, but the enzymatic activity of NEIL1 was dispensable. Furthermore, our results revealed that NEIL1 relied on interactions with the N- and C-terminus of the nucleoprotein (NP) of IAV, and NEIL1 expression facilitated the entry of the NP into the nucleus, which further enhanced the stability of the viral ribonucleoprotein (vRNP) complex and thus contributed to IAV replication and transcription. These findings reveal an enzyme-independent mechanism of host NEIL1 that negatively regulates IFN-β expression, thereby facilitating IAV propagation. Our study provides new insights into the roles of NEIL1, both in directly promoting virus replication and in evading innate immunity in IAV infection.

IMMU-11. GUARDIANS OF INNATE IMMUNE ACTIVATION: CRUCIAL ROLES OF NONO AND CGAMP IN GLIOMA VIROTHERAPY

Abstract Despite aggressive therapeutic interventions, glioblastoma patients face a median survival of seven months after tumor recurrence. Alarmingly, there has been no improvement to the standard of care for two decades, and patients still receive toxic doses of radiation and chemotherapy, rendering many unable to perform daily functions. An emerging approach, oncolytic virotherapy (OV) using Delta-24-RGD, is gaining traction due to recent clinical trials (NCT00805376, NCT03178032, and NCT02798406) exhibiting robust responses in subsets of patients. While these studies demonstrated the therapeutic potential of OV, findings also indicate the early clearance of the virus, hindering the establishment of an effective anti-tumor immune response in most patients. We propose that mitigating the innate immune response against the therapeutic virus should result in improved intratumoral persistence, increasing the window of opportunity for developing an anti-tumor immune response. RNA-sequencing identified the non-POU domain containing octamer-binding (NONO) pathway as highly upregulated in syngenic glioma models and further amplified by OV treatment. In-vitro RNA sequencing and comparative analysis complemented these results to define a unique transcriptomic profile induced by adenovirus infection. LC-MS/MS identified host cGAS and adenoviral capsid proteins as candidate binding partners of NONO, which were validated using co-immunoprecipitation. Although the type I interferon cluster is deleted in most gliomas, tumor cells have a profound influence on their microenvironment through the secretion of the second messenger cGAMP. We show that NONO is required for cGAMP production, providing a mechanism to modulate antiviral responses in the tumor microenvironment during OV. Our findings underscore the significance of cGAMP shed from tumor cells in response to OV, and how NONO interacts with cGAS in the nucleus to sensor adenovirus infection. These findings uncover novel innate immunity mechanisms in gliomas and will inform the design of more efficacious oncolytic adenoviruses for glioma therapy.

IFITM1 is a host restriction factor that inhibits porcine epidemic diarrhea virus infection.

Porcine epidemic diarrhea virus (PEDV) infection and transmission pose a serious threat to the global swine industry. The search for a new host factor with anti-PEDV effect may be an effective potential target for the development of novel antiviral drugs. Interferon-induced transmembrane proteins (IFITMs) play a crucial role in the innate immune response triggered by viral infection, and it has been suggested that IFITMs can block the early stages of viral replication, but the mechanism of action is currently unclear. The current study sheds light on the role of IFITM1 in PEDV infection. Specifically, overexpression of IFITM1 suppresses PEDV proliferation in IPEC-J2 cells, while knockdown of IFITM1 has the opposite effect. Collectively, these findings underscore IFITM1's inhibitory role in PEDV infection, with critical implications for the residues and structural motifs within its CTD. The study demonstrates that IFITM1, an interferon-induced transmembrane protein, plays a critical role in the antiviral response against Porcine Epidemic Diarrhea Virus (PEDV). Notably: Overexpression of IFITM1 suppresses PEDV proliferation.IFITM1 co-localizes with PEDV virions in the cytoplasm surrounding the nucleus.Immunocolloidal gold electron microscopy reveals IFITM proteins embedded on the surface of PEDV virions.IFITM1 directly interacts with the N protein of PEDV.C-terminal domain mutations in IFITM1 compromise its inhibitory function against PEDV, with specific amino acid residues playing a pronounced role.These findings enhance our understanding of innate immunity and antiviral defense mechanisms, with potential implications for therapeutic strategies against PEDV infection. The study establishes IFITM1 as a key player in the antiviral response against PEDV. Its inhibitory function, co-localization with virions, and interaction with the N protein provide valuable insights. Notably, the CTD mutations of IFITM1 have a fundamental impact on its modulatory action. These findings contribute to our understanding of innate immunity and antiviral defense mechanisms, with potential implications for therapeutic strategies against PEDV infection.

Age-specific dynamics of neutralizing antibodies, cytokines, and chemokines in response to La Crosse virus infection in mice.

La Crosse virus (LACV) is a primary cause of pediatric arboviral encephalitis in the United States, particularly affecting children aged 16 years or younger. This age-related susceptibility extends to murine models, where weanling mice (3 weeks old) succumb to LACV infection, while adults (≥6 weeks old) demonstrate resistance. Despite its clinical relevance, the host immune response to LACV is not fully understood. In this study, we investigated the roles of neutralizing antibodies (nAbs), cytokines, and chemokines in weanling and adult mice following infection with 5 × 105 plaque-forming units (PFU) of LACV. Weanling mice demonstrated early disease onset with elevated peripheral viremia, but passive transfer of adult serum, confirmed to have nAbs, to naïve weanlings prior to infection completely rescued them from death. Moreover, adult mice had increased Th1 cytokines, Th9/Th17/Th22/Treg cytokines, and many chemokines. In contrast, weanlings had higher Th2 cytokines, correlating with symptoms onset. Flow cytometry and intracellular cytokine staining further demonstrated that weanling mice produced higher levels of IL-4 by CD4+ and CD8+ T cells compared to adults, regardless of infection status. Conversely, LACV-infected adult mice had increased IFN-γ production by CD8+ T cells compared to uninfected controls. Finally, the adoptive transfer of splenocytes from immune adult mice to naïve weanlings delayed neurological symptoms and improved survival. In conclusion, this study links nAbs and cytokine and chemokine responses to protective immunity in adult mice, contrasting with the pathogenesis seen in weanlings. These findings underscore the importance of further research into innate and adaptive immune mechanisms during LACV infection.IMPORTANCELa Crosse virus (LACV) is a primary cause of pediatric encephalitis in the United States, with an impact on children aged 16 years or younger. This age-related susceptibility is recapitulated in mouse models, where young mice succumb to LACV-induced disease, while adults demonstrate resistance. Our understanding of host responses to LACV remains underexplored. This study sheds light on the dynamics of neutralizing antibodies (nAbs), cytokines, and chemokines following LACV infection in both adult and weanling mice. Our study reveals age-specific variations in viremia, neutralizing antibody titers, survivability, and levels of cytokines and chemokines. Adult mice exhibit significantly elevated levels of Th1 cytokines, contrasting with elevated levels of Th2 cytokines observed in weanling mice, often coinciding with the onset of symptoms. These data reveal age-specific dynamics in cytokines and chemokines associated with protective versus pathogenic immunity, emphasizing the need for further studies on innate and adaptive immunity.

Shrimp Intestinal Microbiota Homeostasis: Dynamic Interplay Between the Microbiota and Host Immunity

ABSTRACTThe shrimp intestine harbors a microbiota that has pivotal roles for host's physiology. Imbalance of shrimp intestinal microbiota has been shown closely related to the occurrence of diseases. The morphological and biological features of the shrimp intestine are considered suboptimal for stable microbial colonization, making the intestinal microbiota composition highly susceptible to the impact of environmental changes or stressors, and particularly unstable. Therefore, the relative unsteadiness of the microbiota composition represents a continuous threat to host survival. Shrimp intestinal microbiota homeostasis is achieved through a dynamic interplay between the microbiota and the host's innate immunity. The shrimp intestine possesses effective innate immune mechanisms that can suppress the uncontrolled proliferation of microbiota components, and simultaneously protect the microbiota from elimination. The mechanism(s) by which the microbial components and the intestinal innate immunity interact with each other to achieve homeostasis represents an interesting interplay between host and microbiota. This review summarizes the current knowledge about intestinal microbiota colonization in shrimp, as well as the intricate mechanisms employed by the intestinal immune system to regulate this microbiota. Moreover, the potential intervention strategies to promote and protect shrimp intestinal homeostasis by modulating the microbiota are also discussed. Thus, this review seeks to comprehensively analyze the current information and contribute to a deeper understanding of the complex interplay between the shrimp intestinal microbiota and innate immunity in maintaining shrimp intestinal homeostasis and overall health. This enhanced understanding may potentially open new avenues for aquaculture management and disease mitigation strategies, ultimately benefiting the shrimp farming industry.

Identification and functional characterization of CD209 homologous genes in zebrafish.

Innate immune responses play a crucial role in maintaining homeostasis, their initiation closely related to pattern recognition receptors or damage-associated molecules on the surface of innate immune cells. CD209, a pattern recognition receptor on the surface of macrophages or dendritic cells, plays an important role in immune functions. However, the impact of CD209 on innate immune cells such as macrophages or neutrophils in vivo remains unclear. In this study, through multiple sequence alignment and phylogenetic tree construction, three genes homologous to human CD209 were found in zebrafish. These are cd209(Ensembl ID:ENSDARG00000029461), zgc:174904(Ensembl ID:ENSDARG00000059049) and si:dkey-187I7.2(Ensembl ID: ENSDARG00000096624).Compared to the cd209 and si:dkey-187i8.2 genes in the Ensembl database, zgc:174904 is more similar to human CD209 in sequence. Using whole-mount in situ hybridization and fluorescence co-localization experiments, it was found that zgc:174904 is mainly expressed in macrophages. Further morpholino knockdown experiments showed that knocking down zgc:174904 leads to an upregulation of M1-type macrophage-related genes and a decrease in the number of mature neutrophils, indicating that zgc:174904 is functionally more similar to CD209. These findings not only reveal the potential role of CD209 in regulating macrophage function and neutrophil development but also provide significant insights for research into the mechanisms of innate immunity.

Features of changes in nonspecific factors of immunological reactivity in obesity

Introduction. The study of pathogenetic factors of obesity is an urgent task of modern medicine. The formation of obesity is characterized by changes in the activity of individual mechanisms of innate immunity. At the same time, the values of laboratory indicators that characterize them are often within the current boundaries of the reference values of laboratory indicators of the immunity of a healthy person. This complicates the pathogenetic assessment of the mechanisms of nonspecific immunological reactivity in obesity and determines the need for further study of the characteristics of nonspecific immune defense factors in this pathology.Aim. To identify the features of changes in cellular and humoral factors of nonspecific immunological reactivity in obesity.Materials and methods. A single-center cross-sectional, one-time controlled study was conducted with the participation of 118 people, of which 87 people were obese patients (BMI 37.2 [34.1; 42.05] kg/m2), 31 people had normal body weight (BMI 21.9 [ 20.2; 23.5] kg/m2) and were included in the control group. All patients underwent a study of lipid profile (total cholesterol, high-density lipoproteins, low-density lipoproteins, very low-density lipoproteins, triglycerides), carbohydrate metabolism (glucose, insulin, glycated hemoglobin), C-reactive protein, indicators of cellular and humoral factors of nonspecific immunity (leukogram, cytokine profile, C3-C4 complement components).Results. An increase in the total number of leukocytes was revealed, due to neutrophil granulocytes against the background of the development of a disproportion between the percentage and absolute value of the number of lymphocytes and monocytes, the concentration of C3 and C4 complement components, C-reactive protein, as well as an increase in the level of IL-6, which confirms the presence of low-grade chronic inflammation in obese patients. Statistically significant correlations of immunological parameters with anthropometric data, indicators of carbohydrate and lipid metabolism were revealed.Conclusion. The results of the study indicate that obesity causes activation of certain cellular and humoral mechanisms of nonspecific immune defense involved in the formation of the inflammatory process. Confirmation of the presence of a latent inflammatory process in obesity is an increase in the level of leukocytes and their individual cellular forms, C-reactive protein, C3 and C4 complement components, IL-6. A feature of the changes is the presence of fluctuations in the values of the studied indicators within the current boundaries of the reference values of laboratory indicators, which makes it difficult to timely diagnose chronic inflammation in obesity

Alterations in expression of TLR2 and TLR4 during successful and pathological aging

The generally accepted theory of aging is the theory of inflammaging. The leading role in its development is played by the mechanisms of innate immunity. Key receptors of innate immunity are TLRs. The patterns of age-related changes in the functioning of the TLR system remain the subject of study. The purpose of the work is to study the expression of TLR2 and TLR4 receptors in peripheral blood cells of centenarians and elderly people at the level of genes and surface molecules. The study analyzed the expression of genes and molecules TLR2 and TLR4 in young donors (n = 50), elderly people (n = 50) and centenarians (n = 100). Analysis of TLR2 and TLR4 gene expression was carried out using RT-PCR. Determination of surface expression of TLR2 and TLR4 was carried out using flow cytofluorimetry. This study is the first to analyze the age-related dynamics of expression of genes and molecules TLR2 and TLR4. It was revealed that in groups of elderly patients and long-livers, TLR2 expression is increased both at the gene and on the cell surface, compared to young donors. In contrast, TLR4 expression decreased with age. Studied groups of patients were divided depending on the aging phenotype into two subgroups: successful and pathological aging. In elderly individuals, TLR2 is increased in both phenotypes, while TLR4 is decreased in the pathological aging. In the group of centenarians with a pathological aging, a decrease in both TLR2 and TLR4 is observed, compared with young. In long-livers with successful aging, an increase in TLR2 expression was observed at the gene and protein level and TLR4 expression was comparable to the group of young individuals. Identified changes in the expression of TLR2 and TLR4, observed in different age groups, can be considered as markers of various aging phenotypes.

Eosinophil-Airway Epithelial Cells crosstalk reveals the eosinophils-mediated DUOX1 up-regulation in a murine allergic inflammation setting.

Blood and airway eosinophilia represent markers for the endotype-driven treatment of allergic asthma. Little is known on mechanisms that link eosinophils and airway epithelial cells before and after these cells are infiltrated by eosinophils during allergic response. Given that innate immune mechanisms, mainly mediated by epithelial-derived cytokines (IL-33, IL-25, TSLP), induce eosinophil-maturing/attractive substances, we thought to evaluate the crosstalk between eosinophils and airway epithelial cells in the context of IL-33-mediated allergic inflammation. DUOX1 was previously described in clinically relevant aspects of allergic inflammation in a HDM -induced allergic asthma mice model, and in patients with chronic sinusitis or allergic asthma. Thus, we evaluated the involvement of HDM and eosinophils in the regulation of DUOX1 in airway epithelial cells. To recapitulate the lung environment present at the allergen challenge time in acute asthma, we set up an in vitro model based on murine bone marrow-derived eosinophils differentiated with IL-5 and then activated with IL-33 (EOs33) and TC1 or C57 airway epithelial cells. We found that treatment of epithelial cells with HDM induced an eosinophil-attractive environment and increased DUOX1 expression. Importantly, we found that the co-culture of airway epithelial cells with EOs33 or with conditioned medium from EOs33 enhanced the expression of DUOX1, which was further increased by combined stimulation (HDM plus EOs33). Our results suggest that lung recruited EOs once activated by IL-33 could be involved in a crosstalk loop with airway epithelial cells by DUOX1-mediated IL-33 secretion.

Caspase-1 in Cx3cr1-expressing cells drives an IL-18-dependent T cell response that promotes parasite control during acute Toxoplasma gondii infection.

Inflammasome activation is a robust innate immune mechanism that promotes inflammatory responses through the release of alarmins and leaderless cytokines, including IL-1α, IL-1β, and IL-18. Various stimuli, including infectious agents and cellular stress, cause inflammasomes to assemble and activate caspase-1. Then, caspase-1 cleaves targets that lead to pore formation and leaderless cytokine activation and release. Toxoplasma gondii has been shown to promote inflammasome formation, but the cell types utilizing caspase-1 and the downstream effects on immunological outcomes during acute in vivo infection have not been explored. Here, using knockout mice, we examine the role of caspase-1 responses during acute T. gondii infection globally and in Cx3cr1-positive populations. We provide in vivo evidence that caspase-1 expression is critical for, IL-18 release, optimal interferon-γ (IFN-γ) production, monocyte and neutrophil recruitment to the site of infection, and parasite control. Specifically, we find that caspase-1 expression in Cx3cr1-positive cells drives IL-18 release, which potentiates CD4+ T cell IFN-γ production and parasite control. Notably, our Cx3cr1-Casp1 knockouts exhibited a selective T cell defect, mirroring the phenotype observed in Il18 knockouts. In further support of this finding, treatment of Cx3cr1-Casp1 knockout mice with recombinant IL-18 restored CD4+ T cell IFN-γ responses and parasite control. Additionally, we show that neutrophil recruitment is dependent on IL-1 receptor accessory protein (IL-1RAP) signaling but is dispensable for parasite control. Overall, these experiments highlight the multifaceted role of caspase-1 in multiple cell populations contributing to specific pathways that collectively contribute to caspase-1 dependent immunity to T. gondii.

Systematic perturbation screens identify regulators of inflammatory macrophage states and a role for TNF mRNA m6A modification.

Macrophages exhibit remarkable functional plasticity, a requirement for their central role in tissue homeostasis. During chronic inflammation, macrophages acquire sustained inflammatory 'states' that contribute to disease, but there is limited understanding of the regulatory mechanisms that drive their generation. Here we describe a systematic functional genomics approach that combines genome-wide phenotypic screening in primary murine macrophages with transcriptional and cytokine profiling of genetic perturbations in primary human macrophages to uncover regulatory circuits of inflammatory states. This process identifies regulators of five distinct states associated with key features of macrophage function. Among these regulators, loss of the N6-methyladenosine (m6A) writer components abolishes m6A modification of TNF transcripts, thereby enhancing mRNA stability and TNF production associated with multiple inflammatory pathologies. Thus, phenotypic characterization of primary murine and human macrophages describes the regulatory circuits underlying distinct inflammatory states, revealing post-transcriptional control of TNF mRNA stability as an immunosuppressive mechanism in innate immunity.