Regulation Of Immune Responses Research Articles

Bronchus-associated lymphoid tissue in lung transplantation: a facilitator of rejection or regulator of tolerance?

The role of bronchus-associated lymphoid tissue (BALT) in the regulation of immune responses to transplanted lungs remains an area of interest and controversy. Early studies in a rat pulmonary transplant model suggested BALT may accelerate rejection of grafts by inducing a local and systemic inflammatory response. Such observations were corroborated in intrapulmonary tracheal transplant models in the rat. While some human studies have described the presence of BALT in grafts that have been chronically rejected, others did not observe an association between induction of BALT and adverse outcomes. More recent investigations have found that BALT, enriched in immunoregulatory cell populations, is induced in tolerant mouse lung allografts, suggesting that such structures may be protective against rejection. Thus, the role of BALT in lung transplantation biology is complex. Insights gained from studies that focus on the role of BALT in lung transplantation may be harnessed to develop new therapies.

Comprehensive genome-wide identification and functional characterization of mapk gene family in northern snakeheads (Channa argus)

The mitogen-activated protein kinase (MAPK) signaling cascade, integral to cellular regulation, orchestrates cell growth, differentiation, stress response, and inflammatory reactions to adapt to challenging environments. The northern snakeheads (Channa argus), a valuable freshwater species known for its hypoxia tolerance, rapid growth, and high nutritional value, lacks comprehensive research on its mapk gene family. In this study, we identified 16 mapk genes in northern snakeheads, among which mapk8, mapk12 and mapk14 have duplicate copies. Phylogenetic analysis confirmed the evolutionary conservation of this gene family. Structural and motif analyses further underscored the conserved nature of these genes. Expression pattern analysis under abiotic and biotic stress conditions showed significant differences expression of mapks in the gills and suprabranchial organ (SBO) after air exposure, as well as in the brain following cold stress, highlighting the extensive role of mapks in stress regulation. It was worth noting that the significant expression differences of mapks were also observed in the spleen after N. seriolae infection, implicating that these genes may be involved in the regulation of innate immune responses. Additionally, analysis of protein-protein interaction (PPI) networks suggested that the co-activation of multiple MAPK signaling pathways may play a key role in regulating an organism's response to biotic and abiotic stresses. This study provides a detailed description of the mapk gene family in the northern snakeheads and elucidates its biological functions under various stress conditions, offering valuable insights into the regulatory mechanisms of the mapk gene family.

Characterization of tripartite motif containing 59 (TRIM59) in Epinephelus akaara: Insights into its immune involvement and functional properties in viral pathogenesis, macrophage polarization, and apoptosis regulation

The tripartite motif-containing (TRIM) superfamily is the largest family of RING-type E3 ubiquitin ligases that is conserved across the metazoan kingdom. Previous studies in mammals have demonstrated that TRIM59 possesses ubiquitin-protein ligase activity and acts as a negative regulator of NF-κB signaling. However, TRIM59 has rarely been characterized in fish. This study aimed to characterize TRIM59 from Epinephelus akaara (Eatrim59) and elucidate its structural features, expression patterns, and functional properties in innate immune responses and in the regulation of apoptosis. Eatrim59 is composed of 406 amino acids with a molecular weight of 45.84 kDa and a theoretical isoelectric point of 5.25. It comprises a conserved RING domain, a B-box motif, and a coiled-coil region. Subcellular localization analysis revealed that Eatrim59 was localized in the endoplasmic reticulum. Eatrim59 was ubiquitously expressed in all tissues examined, with the highest relative expression detected in the blood, followed by the brain and spleen. Temporal expression of Eatrim59 was dynamically regulated in response to in vivo immune stimulation by Toll-like receptor ligands and nervous necrosis virus infection. In FHM cells overexpressing Eatrim59, an increase in viral replication was observed upon infection with the Viral hemorrhagic septicemia virus. This phenomenon is attributed to Eatrim59-mediated downregulation of interferon, pro-inflammatory cytokines, and other antiviral pathways. Moreover, macrophages stably overexpressing Eatrim59 exhibited a decrease in nitric oxide production and the formation of a filamentous actin structure upon lipopolysaccharide stimulation, indicating dampened M1 polarization. Furthermore, a decrease in apoptosis was observed in Eatrim59-overexpressing FHM cells under oxidative stress induced by H2O2. In conclusion, these findings demonstrate the multifaceted role of Eatrim59 as a regulator of innate immune response and apoptosis in E. akaara.

Huang-Lian-Jie-Du decoction ameliorates sepsis through dynamic regulation of immune response and gut microbiota-metabolite axis.

Sepsis remains a life-threatening condition with high mortality rates despite current therapeutic approaches. While Huang-Lian-Jie-Du Decoction (HLJDD), a traditional Chinese medicine formula, has been historically used to treat inflammatory conditions, its therapeutic potential in sepsis and underlying mechanisms remain unexplored. This study investigated HLJDD's comprehensive effects on sepsis pathophysiology using a rat cecal ligation and puncture (CLP) model. HLJDD significantly improved survival rates and demonstrated sophisticated immunomodulatory effects through temporal regulation of the biphasic immune response characteristic of sepsis. In early sepsis, HLJDD suppressed pro-inflammatory cytokines (IL-1β, IL-6) while maintaining defensive inflammation. During late sepsis, it counteracted immunosuppression by reducing IL-10 levels and CD4+CD25+ T cell populations while protecting CD4+ and CD8+ T cells from apoptosis. Notably, HLJDD demonstrated dynamic regulation of the gut microbiota-metabolite axis. It enhanced beneficial bacterial populations (Firmicutes, Lactobacillus) while suppressing potentially pathogenic species (Bacteroides, Parabacteroides). Metabolomic analysis revealed time-dependent modulation of short-chain fatty acids, with elevated levels at 12h followed by strategic reduction at 18-30h, coordinating with changes in SCFA-producing bacteria. This temporal metabolic regulation corresponded with improved intestinal barrier function and balanced immune responses. The study unveils HLJDD's novel mechanism of action through synchronized modulation of immune responses, gut microbiota, and metabolite profiles, presenting a multi-target therapeutic approach that addresses the complex pathophysiology of sepsis. These findings provide a strong foundation for further clinical investigation of HLJDD as an innovative treatment strategy for sepsis.

Viral influencers: deciphering the role of endogenous retroviral LTR12 repeats in cellular gene expression.

The human genome is like a museum of ancient retroviral infections. It contains a large number of endogenous retroviruses (ERVs) that bear witness to past integration events. About 5,000 of them are so-called long terminal repeat 12 (LTR12) elements. Compared with 20,000 human genes, this is a remarkable number. Although LTR12 elements can act as promoters or enhancers of cellular genes, the function of most of these retroviral elements has remained unclear. In our mini-review, we show that different LTR12 elements share many similarities, including common transcription factor binding sites. Furthermore, we summarize novel insights into the epigenetic mechanisms governing their silencing and activation. Specific examples of genes and pathways that are regulated by LTR12 loci are used to illustrate the regulatory network built by these repetitive elements. A particular focus is on their role in the regulation of antiviral immune responses, tumor cell proliferation, and senescence. Finally, we describe how a targeted activation of this fascinating ERV family could be used for diagnostic or therapeutic purposes.

Gonadal miRNomes and transcriptomes in infected fish reveal sexually dimorphic patterns of the immune response.

Fish disease outbreaks caused by bacterial burdens are responsible for decreasing productivity in aquaculture. Unraveling the molecular mechanisms activated in the gonads after infections is pivotal for enhancing husbandry techniques in fish farms, ensuring disease management, and selecting the most resilience phenotype. The present study, with an important commercial species the European sea bass (Dicentrarchus labrax), an important commercial species in Europe, examined changes in the miRNome and transcriptome 48h after an intraperitoneal infection with Vibrio anguillarum. The findings indicate that following infection, testes exhibited more pronounced alterations in both the miRNome and transcriptome. Specifically, males showed approximately 26% more differentially expressed genes in testicular genes compared to females (2,624 vs. 101 DEGs). Additionally, four miRNAs (miR-183-5p, miR-191-3p, miR-451-5p, and miR-724-5p) were significantly expressed post-infection in males, while none were identified in females. Interestingly, upon deep analysis of sexual dimorphic gene modules, a larger number of miRNAs were identified in infected females targeting genes related to the immune system compared to infected males. These results suggest that fish ovaries demonstrate greater resilience in response to infections by suppressing genes related to the immune system through a post-transcriptional mechanism performed by miRNAs. In contrast, testes activate genes related to the immune system and repress genes related to cellular processes to cope with the infection. In particular, the crosstalk between the miRNome and transcriptome in infected males revealed a pivotal gene, namely, insulin-like growth factor binding protein (igfbp), acting as a gene network hub in which miR-192-3p was connected. The current study elucidated the need to comprehend the basic immune regulatory responses associated with miRNAs and gene regulation networks that depend on fish sex. The data reveal the importance of considering sex as a factor in interpreting the immune system in fish to generate efficient protocols to prevent outbreaks in fish farms.

The Role of Gut Microbiota in Shaping Immune Responses in Tephritidae Fruit Fly and Prospective Implications for Management.

The interaction of microbial communities with host immunity has become one of the most explored research areas with significant implications for pest control strategies. It has been found that the gut microbiota plays substantial roles in immune response regulation and host-gut microbiome symbiosis, as well as in pathogen resistance and overall fitness in Tephritidae fruit flies that are major pests of agricultural importance. In this review, we discuss the modulation of immune responses of Tephritidae fruit flies by the gut microbiota with particular emphasis on the general interactions between microbiota and the immune system. These interactions help to unravel new horizons of pest management. Regulating gut microbiota modifies the performance of biological control agents and SIT and allows the creation of microbial therapies that affect the vital physiological functions of fruit flies. Besides, deploying microbes that can modulate the immune response and using microbial-derived signals provide an eco-friendly and more sustainable way of eradicating chemical pesticides and making farming systems less susceptible to climatic variability. This paper reviews various aspects of the possibility of using gut microbiota for changing the approach to Integrated Pest Management (IPM) programs that would improve methods of controlling Tephritidae fruit fly populations more ecologically.

Chromosome-Level Genome Assembly and Comparative Genomic Analysis of Planiliza haematocheilus: Insights into Environmental Adaptation and Hypoxia Tolerance Mechanisms.

Planiliza haematocheilus, a teleostan species noted for its ecological adaptability and economic significance, thrives in both freshwater and marine environments. This study presents a novel chromosome-level genome assembly through Hi-C, PacBio CCS, and Illumina sequencing methods. The assembled genome has a final size of 651.58Mb, with 24 chromosomes anchoring 91.94% of contigs. Contig N50 and scaffold N50 are respectively measured at 25.52Mb and 28.59Mb. Of the 22,476 protein-coding genes identified in the genome, 21,834 have functional annotations. BUSCO (Benchmarking Universal Single-Copy Orthologs) genome and gene annotation assessments yielded scores of 96% and 96.6%, respectively. The genome of P. haematocheilus revealed 228 expanded and 1433 contracted gene families. Comparative genomic analyses highlight adaptations and hypoxia tolerance, linked to protein synthesis, immune response, and metabolic regulation. The high-quality genome assembly supports advanced studies on gene expression patterns under different environmental stressors, contributing to genetic enhancement efforts for this economically important aquaculture species.

Transcellular regulation of ETI-induced cell death.

To address the persistent challenge of cell death spread and limitation during effector-triggered immunity (ETI), we propose a 'concentric circle' model. This model outlines a regulatory framework, integrating multiple cells and diverse signaling molecules, including salicylic acid (SA), jasmonic acid (JA), and Ca2+. By accounting for the varying concentrations and spatiotemporal distributions of these molecules, our model aims for precision in immune defense and regulated cell death. To validate this model, a pathosystem-triggering ETI without pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) is required. Here, we review potential ETI elicitors, including victorin, thaxtomin A, and second messengers. We anticipate that future discovery of 'pure' ETI-triggering effectors will provide deeper insights into the transcellular regulation of immune response in plants.

Inhibiting NLRP3 enhances cellular autophagy induced by outer membrane vesicles from Pseudomonas aeruginosa.

The bacterium Pseudomonas aeruginosa is able to invade lung epithelial cells and survive intracellularly. During this process, it secretes outer membrane vesicles (OMVs), however, it is currently unclear how OMVs from P. aeruginosa (PA-OMVs) affect lung epithelial cells and their impact on oxidative stress, autophagy, and other physiological activities of lung epithelial cells. In this study, we found that PA-OMVs activated oxidative stress and autophagy in cells. We demonstrated that the NLRP3 (NLR family, pyrin domain containing 3) inhibitor MCC950 can enhance autophagy induced by PA-OMVs. The main function of NLRP3 is related to the body's immune response and inflammation regulation. MCC950 is the most common inhibitor of NLRP3. Additionally, we showed that PA-OMVs not only enhanced the expression of AMP-activated protein kinase, a key regulator of cellular energy homeostasis, and reactive oxygen species, which play a crucial role in cellular signaling and oxidative stress, but also significantly enhanced the expression of NLRP3. Inhibiting the expression of NLRP3 further enhanced the process of PA-OMVs induced autophagy. These results demonstrate that PA-OMVs activate both autophagy and the NLRP3 inflammasome, with NLRP3 suppressing autophagy to a certain extent, hoping to provide broad ideas for the future applications of PA-OMVs.IMPORTANCEThe discovery that lung epithelial cells exposed to outer membrane vesicles from Pseudomonas aeruginosa (PA-OMVs) activate cellular autophagy and induce protective immunity is significant. Specifically, the addition of an NLRP3 inhibitor, MCC950, has been found to decrease NLRP3 targets while simultaneously enhancing the autophagy activity induced by PA-OMVs. This finding unveils a novel theoretical framework for the development of PA-OMVs vaccines, highlighting new targets for enhancing the body's anti-infective responses. By elucidating the mechanisms through which PA-OMVs trigger autophagy and bolster immune defenses, this research opens avenues for innovative vaccine design strategies aimed at combatting infections effectively.

Integration of Mendelian Randomization to explore the genetic influences of pediatric sepsis: a focus on RGL4, ATP9A, MAP3K7CL, and DDX11L2

ObjectiveThis study aims to explore the genetic characteristics of pediatric sepsis through a combined analysis of multiple methods, including Mendelian Randomization (MR), differential gene expression analysis, and immune cell infiltration assessment. It explores their potential as biomarkers for sepsis risk and their involvement in immune-related pathways.MethodsDifferential expression analysis was performed using public datasets to identify genes with significant expression changes between pediatric sepsis patients and healthy controls. MR analysis utilized genome-wide significant SNPs as instrumental variables to assess causal relationships between gene expression and sepsis risk. Bi-directional MR was conducted to assess both forward and reverse causality. FDR correction was applied to adjust for multiple comparisons in MR results. Immune cell infiltration analysis was performed to investigate the genes’ roles in immune responses, and findings were validated with independent datasets. ROC curves were constructed to assess predictive performance.ResultsDifferential expression analysis identified significant changes in RGL4,ATP9A,MAP3K7CL, and DDX11L2. MR analysis revealed causal associations between these genes and sepsis risk, with RGL4 and ATP9A upregulated (inflammatory roles), and MAP3K7CL and DDX11L2 downregulated (protective roles). Bi-directional MR found no significant reverse causality. Immune cell analysis showed associations with key immune cell types, and ROC analysis demonstrated strong predictive potential.ConclusionRGL4,ATP9A,MAP3K7CL, and DDX11L2 play important roles in pediatric sepsis risk and immune response regulation, offering insights into genetic and immune mechanisms that may inform future sepsis research and treatment.

Role of Crosstalk Between Gut Microbiota and Immune Cells in Colorectal Cancer: A Narrative Review

Abstract Colorectal cancer (CRC) ranks among the most prevalent and deadly cancers globally, with its incidence increasing due to lifestyle factors such as increased consumption of red meat and decreased vegetable intake. A distinctive aspect of CRC is its strong connection to the gut microbiota, which is crucial in both tumorigenesis and immune regulation. This narrative review provides a comprehensive analysis of the interactions between gut microbiota and the immune system, focusing on their importance in CRC progression and responses to immunotherapy. Imbalances in the composition of gut microbes are strongly associated with CRC development. Notably, species such as Fusobacterium nucleatum and Bacteroides fragilis have been identified as key regulators of immune responses within the tumor microenvironment. These microbes affect the functions of immune cells, such as T cells, macrophages and myeloid-derived suppressor cells, thereby influencing cancer progression and prognosis. Additionally, this review underscores the potential of gut microbiota as biomarkers for CRC detection and outcome prediction. There is also growing interest in the use of probiotics, fecal microbiota transplantation and dietary modifications as supplementary treatments. A deeper understanding of how microbial communities interact with the immune system may pave the way for novel personalized therapies, particularly by enhancing the effectiveness of immune checkpoint inhibitors.

In vivo CRISPR screening identifies tada2b as a key epigenetic regulator of immune response in adrenocortical carcinoma

<i>In vivo</i> CRISPR screening identifies tada2b as a key epigenetic regulator of immune response in adrenocortical carcinoma

Targeting Nanotherapeutics for Highly Efficient Diagnosis and Treatment of Systemic Lupus Erythematosus through Regulation of Immune Response

Systemic lupus erythematosus (SLE) is characterized by the production of pathogenic autoantibodies, particularly antidouble‐stranded (ds) DNA antibodies, which contribute to multiorgan damage (lupus nephritis, LN). Hence, there is an urgent need to recognize and eliminate SLE‐specific anti‐ds DNA antibodies to enhance the SLE treatment. Herein, mesoporous silica (MSNs) loaded with SeC and surface‐modified ctDNA are constructed to effectively specific bind and eliminate pathogenic anti‐dsDNA antibodies for treatment SLE in 125 plasm and enabling swift LN diagnosis in 36 kidney tissue from SLE patients. As expected, the clearance ratio of anti‐dsDNA antibodies by nanotherapeutics is significantly greater compared to other products commonly used in clinical therapies and exhibits biocompatibility and safety in patients. Moreover, MSNs‐DNA can also help visualize the distribution of anti‐dsDNA antibodies in the lesions of the kidney. Importantly, the combination strategy (MSNs‐DNA@SeC) can effectively remove antibodies and reduce UP production by the regulation of B cells and T cells in female MRL/lpr SLE model mice to alleviate related symptoms. Collectively, the resultant data not only presents a straightforward method for the systematic design of nanomedicine targeting SLE to enhance the effects on diagnosis and treatment, but also elucidates the potential mechanisms involving anti‐dsDNA antibodies in the pathogenesis and progression of SLE.

Advancements in drug discovery: integrating CADD tools and drug repurposing for PD-1/PD-L1 axis inhibition.

Despite significant strides in improving cancer survival rates, the global cancer burden remains substantial, with an anticipated rise in new cases. Immune checkpoints, key regulators of immune responses, play a crucial role in cancer evasion mechanisms. The discovery of immune checkpoint inhibitors (ICIs) targeting PD-1/PD-L1 has revolutionized cancer treatment, with monoclonal antibodies (mAbs) becoming widely prescribed. However, challenges with current mAb ICIs, such as limited oral bioavailability, adverse effects, and high costs, underscore the need to explore alternative small-molecule inhibitors. In this work, we aimed to identify new potential ICI among all FDA-approved drugs. We employed QSAR models to predict PD-1/PD-L1 inhibition, utilizing a diverse dataset of 29 197 molecules sourced from ChEMBL, PubChem, and recent literature. Machine learning techniques, including Random Forest, Support Vector Machine, and Convolutional Neural Network, were employed for benchmarking to assess model performance. Additionally, we undertook a drug repurposing strategy, leveraging the best in silico model for a virtual screening campaign involving 1576 off-patent approved drugs. Only two virtual screening hits were proposed based on the criteria established for this approach, including: (1) QSAR probability of being active against PD-L1; (2) QSAR applicability domain; (3) prediction of the affinity between the PD-L1 and ligands through molecular docking. One of the proposed hits was sonidegib, an anticancer drug, featuring a biphenyl system. Sonidegib was subsequently validated for in vitro PD-1/PD-L1 binding modulation using ELISA and flow cytometry. This integrated approach, which combines computer-aided drug design (CADD) tools, QSAR modelling, drug repurposing, and molecular docking, offers a pioneering strategy to expedite drug discovery for PD-1/PD-L1 axis inhibition. The findings underscore the potential to identify a wider range small molecules to contribute to the ongoing efforts to advancing cancer immunotherapy.

P0095 Human multi-lineage gut-on-chip to study near-physiological epithelial barrier function and directed secretion

Abstract Background The human intestinal epithelium is composed of diverse cell types, enabling it to fulfil essential digestive functions such as absorption and secretion, while simultaneously acting as an immune interface. This epithelial barrier safeguards underlying immune cells in the lamina propria from luminal antigens by maintaining a mucus layer rich in antimicrobial peptides, preventing unwanted immune responses and allowing regulated cytokine and chemokine gradients. Despite advances in single-cell transcriptomics, understanding specific epithelial cell secretions remains limited. Methods To address this, we developed a human intestinal organ-on-chip (OoC) model, derived from human colon organoids, capable of forming a heterogenous, functional epithelial barrier without permeable supports. This OoC model provides concurrent access to luminal and basal compartments, allowing for mid- to high-throughput screenings, overcoming limitations of conventional transwell or 3D organoid cultures. Results In our study, we analysed barrier function by measuring transepithelial electrical resistance (TEER) and permeability as well as confirming tight junction assemble marked by ZO-1 and occludin. Cell type composition was modulated using distinct culture media, resulting in a heterogeneous cell composition including goblet cells, colonocytes, and enteroendocrine cells along with the proliferative compartment, evidenced by transcriptomic and protein analyses. Cytokine and chemokine secretions, notably CCL2, CCL20, IL-8, IL-18, and CXCL10, demonstrated cell type-dependent and spatially directed patterns, suggesting location-specific secretion along the crypt-surface axis in vivo. Under basal and stimulated conditions, our model retained responsiveness to bacterial stimuli, gluten-derived antigens, and pro-inflammatory conditions, confirming the important role of epithelial cells in immune response regulation. Conclusion Collectively, this OoC model offers a physiologically relevant platform for exploring human intestinal barrier function and epithelial-immune communication. This scalable, multi-lineage in vitro model advances our capacity to study directed secretion, barrier integrity, and epithelial cell type dependent immune response, supporting applications in disease modelling and personalized medicine development.

RAGE-mediated intestinal pro-inflammatory responses triggered by Giardia duodenalis.

Giardia duodenalis is a waterborne zoonotic protozoan that causes gastrointestinal inflammation. Giardiasis and metabolic illnesses share features such as chronic inflammation and intestinal symptoms. Receptor for advanced glycation end products (RAGE) signaling plays a role in metabolic illnesses and intestinal inflammatory responses. The presence of protozoan viruses can influence host immunological responses triggered by protozoa. However, these effects of G. duodenalis remain unknown. In this study, mice treated with the RAGE inhibitor FPS-ZM1 showed more severe intestinal damage, including increased intestinal permeability and lesions, compared to that of the untreated group. Next, we found that G. duodenalis infection activated RAGE, leading to increased secretion of pro-inflammatory cytokines, including IL-1 β, IL-6, IL-12, TNF-α and IFN-γ in mouse intestinal epithelial cells. Notably, these pro-inflammatory responses were significantly higher in Giardiavirus (GLV)-free Giardia than those of GLV-containing Giardia, except for IFN-γ. Additionally, lactate dehydrogenase (LDH) release, GSDMD-N cleavage, and the morphological observation of pyroptosis were significantly higher in cells induced by GLV-free Giardia than those infected with GLV-carrying Giardia. Differences were also observed in the MAPK (p-JNK, p-38, p-ERK) and NF-κB pathway activation, as well as reactive oxygen species (ROS) levels, with higher activation in cells infected by GLV-free Giardia, and the ROS was involved in the regulation of p38 MAPK and JNK activation. These findings reveal the potential of RAGE as a target for developing vaccines or drugs, suggesting the differences in the regulation of host immune responses induced by GLV-free Giardia or GLV-containing Giardia, providing new insights for the prevention and treatment of Giardia.

Uncovering the chromatin-mediated transcriptional regulatory network governing cold stress responses in fish immune cells.

Temperature fluctuations challenge ectothermic species, particularly tropical fish dependent on external temperatures for physiological regulation. However, the molecular mechanisms through which low-temperature stress impacts immune responses in these species, especially in relation to chromatin accessibility and epigenetic regulation, remain poorly understood. In this study, we investigate chromatin and transcriptional changes in the head kidney and thymus tissues of Nile tilapia (Oreochromis niloticus), a tropical fish of significant economic importance, under cold stress. By analyzing cis-regulatory elements in open chromatin regions and their associated transcription factors (TFs), we construct a comprehensive transcriptional regulatory network (TRN) governing immune responses, including DNA damage-induced apoptosis. Our analysis identifies 119 TFs within the TRN, with Stat1 emerging as a central hub exhibiting distinct binding dynamics under cold stress, as revealed by footprint analysis. Overexpression of Stat1 in immune cells leads to apoptosis and increases the expression of apoptosis-related genes, many of which contain Stat1 binding sites in their regulatory regions, emphasizing its critical role in immune cell survival during cold stress. These results provide insights into the transcriptional and epigenetic regulation of immune responses to cold stress in tilapia and highlight Stat1 as a promising target for enhancing cold tolerance in tropical fish species.

Trichinella spiralis extracellular vesicles induce anti-inflammatory and regulatory immune responses in vitro.

The helminth Trichinella spiralis, through its excretory-secretory (ES L1) products, induces immune regulatory mechanisms that modulate the host's immune response not only to itself, but also to bystander antigens, foreign or self in origin, which can result in the alleviation of inflammatory diseases. Under the influence of ES L1, dendritic cells (DCs) acquire a tolerogenic phenotype and the capacity to induce Th2 and regulatory responses. Since ES L1 products represent a complex mixture of proteins and extracellular vesicles (TsEVs) the aim of this study was to investigate the impact of TsEVs, isolated from ES L1 products, on phenotypic and functional characteristics of DCs and to elucidate whether TsEVs could reproduce the immunomodulatory effects of the complete ES L1 product. Monocyte-derived DCs treated with TsEVs acquired semi-matured phenotypes, characterized by low expression of human leukocyte antigen - DR isotype (HLA-DR), cluster of differentiation (CD) 86 (CD86), and CD40, moderate expression of CD83 and C-C chemokine receptor type 7 (CCR7), and increased expression of tolerogenic markers indoleamine 2,3-dioxygenase 1 (IDO-1) and immunoglobulin-like transcript 3 (ILT3), together with the unchanged production of IL-12 and IL-23, and elevated production of IL-10 and transforming growth factor (TGF)-β, compared with controls. Gene expression analysis of TsEV-treated DCs revealed elevated levels of mTOR, Ahr, NF-κB2, RelB, SOCS1 and SOCS3, which participate in signaling pathways involved in DC maturation and the subsequent regulation of release of both anti-inflammatory and pro-inflammatory cytokines. TsEVs promoted the capacity of DCs to drive polarization of Th2 and anti-inflammatory responses, and impaired their capacity to induce Th1/Th17 polarization. Moreover, TsEV-treated DCs possessed a high capacity to induce conventional FoxP3+ regulatory T cells, as well as unconventional T regulatory (Tr1) cells. Tolerogenic properties of TsEV-treated DCs were retained even after challenge with a pro-inflammatory stimulus. These findings highlight the potential of TsEVs to induce immune tolerance, suggesting their potential use as therapeutics for the treatment of inflammatory disorders.

NLRC3 Attenuates Antiviral Innate Immune Response by Targeting IRF7 in Grass Carp (Ctenopharyngodon idelus).

NLRC3 belongs to the NOD-like receptor family and is recognized as a modulator of innate immune mechanisms. In this study, we firstly report that Ctenopharyngodon idelus NLRC3 (CiNLRC3) acts as a negative regulator in the antiviral immune response. Cinlrc3 is ubiquitously expressed across tested tissues, displaying particularly high expression in the intestine, spleen, gill and kidney. Notably, Cinlrc3 expression is markedly upregulated following grass carp reovirus (GCRV) infection both in vivo and in vitro. Functional assays reveal that the overexpression of CiNLRC3 hampers cellular antiviral responses, thereby facilitating viral replication. Conversely, the silencing of CiNLRC3 through siRNA transfection enhances these antiviral activities. Additionally, CiNLRC3 substantially diminishes the retinoic acid-inducible gene I (RIG-I)-like receptor (RLR)-mediated interferon (IFN) response in fish. Subsequent molecular investigations indicates that CiNLRC3 interacts with the RLR molecule node, IRF7 but not IRF3, by degrading the IRF7 protein in a proteasome-dependent manner. Furthermore, CiNLRC3 co-localizes with CiIRF7 in the cytoplasm and impedes the IRF7-induced IFN response, resulting in impairing IRF7-mediated antiviral immunity. Summarily, these findings underscore the critical inhibitory role of teleost NLRC3 in innate immunity, offering new perspectives on its regulatory functions and potential as a target for resistant breeding in fish.