Self-regulation and cross-regulation of pattern-recognition receptor signalling in health and disease

XAF1 promotes anti-RNA virus immune responses by regulating chromatin accessibility

A rapid induction of antiviral genes is critical for eliminating viruses, which requires activated transcription factors and opened chromatins to initiate transcription. However, it remains elusive how the accessibility of specific chromatin is regulated during infection. Here, we found that XAF1 functioned as an epigenetic regulator that liberated repressed chromatin after infection. Upon RNA virus infection, MAVS recruited XAF1 and TBK1. TBK1 phosphorylated XAF1 at serine-252 and promoted its nuclear translocation. XAF1 then interacted with TRIM28 with the guidance of IRF1 to the specific locus of antiviral genes. XAF1 de-SUMOylated TRIM28 through its PHD domain, which led to increased accessibility of the chromatin and robust induction of antiviral genes. XAF1-deficient mice were susceptible to RNA virus due to impaired induction of antiviral genes. Together, XAF1 acts as an epigenetic regulator that promotes the opening of chromatin and activation of antiviral immunity by targeting TRIM28 during infection.

Ethanol mediates the interaction between Caenorhabditis elegans and the nematophagous fungus Purpureocillium lavendulum

Accurately recognizing pathogens by the host is vital for initiating appropriate immune response against infecting microorganisms. Caenorhabditis elegans has no known receptor to recognize pathogen-associated molecular pattern. However, recent studies showed that nematodes have a strong specificity for transcriptomes infected by different pathogens, indicating that they can identify different pathogenic microorganisms. However, the mechanism(s) for such specificity remains largely unknown. In this study, we showed that the nematophagous fungus Purpureocillium lavendulum can infect the intestinal tract of the nematode C. elegans and the infection led to the accumulation of reactive oxygen species (ROS) in the infected intestinal tract, which suppressed fungal growth. Co-transcriptional analysis revealed that fungal genes related to anaerobic respiration and ethanol production were up-regulated during infection. Meanwhile, the ethanol dehydrogenase Sodh-1 in C. elegans was also up-regulated. Together, these results suggested that the infecting fungi encounter hypoxia stress in the nematode gut and that ethanol may play a role in the host-pathogen interaction. Ethanol production in vitro during fungal cultivation in hypoxia conditions was confirmed by gas chromatography-mass spectrometry. Direct treatment of C. elegans with ethanol elevated the sodh-1 expression and ROS accumulation while repressing a series of immunity genes that were also repressed during fungal infection. Mutation of sodh-1 in C. elegans blocked ROS accumulation and increased the nematode's susceptibility to fungal infection. Our study revealed a new recognition and antifungal mechanism in C. elegans. The novel mechanism of ethanol-mediated interaction between the fungus and nematode provides new insights into fungal pathogenesis and for developing alternative biocontrol of pathogenic nematodes by nematophagous fungi. IMPORTANCE Nematodes are among the most abundant animals on our planet. Many of them are parasites in animals and plants and cause human and animal health problems as well as agricultural losses. Studying the interaction of nematodes and their microbial pathogens is of great importance for the biocontrol of animal and plant parasitic nematodes. In this study, we found that the model nematode Caenorhabditis elegans can recognize its fungal pathogen, the nematophagous fungus Purpureocillium lavendulum, through fungal-produced ethanol. Then the nematode elevated the reactive oxygen species production in the gut to inhibit fungal growth in an ethanol dehydrogenase-dependent manner. With this mechanism, novel biocontrol strategies may be developed targeting the ethanol receptor or metabolic pathway of nematodes. Meanwhile, as a volatile organic compound, ethanol should be taken seriously as a vector molecule in the microbial-host interaction in nature.

WDR77 inhibits prion-like aggregation of MAVS to limit antiviral innate immune response

RIG-I-MAVS signaling pathway plays a crucial role in defending against pathogen infection and maintaining immune balance. Upon detecting viral RNA, RIG-I triggers the formation of prion-like aggregates of the adaptor protein MAVS, which then activates the innate antiviral immune response. However, the mechanisms that regulate the aggregation of MAVS are not yet fully understood. Here, we identified WDR77 as a MAVS-associated protein, which negatively regulates MAVS aggregation. WDR77 binds to MAVS proline-rich region through its WD2-WD3-WD4 domain and inhibits the formation of prion-like filament of recombinant MAVS in vitro. In response to virus infection, WDR77 is recruited to MAVS to prevent the formation of its prion-like aggregates and thus downregulate RIG-I-MAVS signaling in cells. WDR77 deficiency significantly potentiates the induction of antiviral genes upon negative-strand RNA virus infections, and myeloid-specific Wdr77-deficient mice are more resistant to RNA virus infection. Our findings reveal that WDR77 acts as a negative regulator of the RIG-I-MAVS signaling pathway by inhibiting the prion-like aggregation of MAVS to prevent harmful inflammation.

Edge Length-Programmed Single-Stranded RNA Origami for Predictive Innate Immune Activation and Therapy

Ligands targeting nucleic acid-sensing receptors activate the innate immune system and play a critical role in antiviral and antitumoral therapy. However, ligand design for in situ stability, targeted delivery, and predictive immunogenicity is largely hampered by the sophisticated mechanism of the nucleic acid-sensing process. Here, we utilize single-stranded RNA (ssRNA) origami with precise structural designability as nucleic acid sensor-based ligands to achieve improved biostability, organelle-level targeting, and predictive immunogenicity. The natural ssRNAs self-fold into compact nanoparticles with defined shapes and morphologies and exhibit resistance against RNase digestion in vitro and prolonged retention in macrophage endolysosomes. We find that programming the edge length of ssRNA origami can precisely regulate the degree of macrophage activation via a toll-like receptor-dependent pathway. Further, we demonstrate that the ssRNA origami-based ligand elicits an anti-tumoral immune response of macrophages and neutrophils in the tumor microenvironment and retards tumor growth in the mouse pancreatic tumor model. Our ssRNA origami strategy utilizes structured RNA ligands to achieve predictive immune activation, providing a new solution for nucleic acid sensor-based ligand design and biomedical applications.

Circular and Circulating DNA in Inflammatory Bowel Disease: From Pathogenesis to Potential Molecular Therapies

Inflammatory bowel diseases (IBD), including Crohn's Disease (CD) and Ulcerative Colitis (UC) are chronic multifactorial disorders which affect the gastrointestinal tract with variable extent. Despite extensive research, their etiology and exact pathogenesis are still unknown. Cell-free DNAs (cfDNAs) are defined as any DNA fragments which are free from the origin cell and able to circulate into the bloodstream with or without microvescicles. CfDNAs are now being increasingly studied in different human diseases, like cancer or inflammatory diseases. However, to date it is unclear how IBD etiology is linked to cfDNAs in plasma. Extrachromosomal circular DNA (eccDNA) are non-plasmidic, nuclear, circular and closed DNA molecules found in all eukaryotes tested. CfDNAs appear to play an important role in autoimmune diseases, inflammatory processes, and cancer; recently, interest has also grown in IBD, and their role in the pathogenesis of IBD has been suggested. We now suggest that eccDNAs also play a role in IBD. In this review, we have comprehensively collected available knowledge in literature regarding cfDNA, eccDNA, and structures involving them such as neutrophil extracellular traps and exosomes, and their role in IBD. Finally, we focused on old and novel potential molecular therapies and drug delivery systems, such as nanoparticles, for IBD treatment.

The role of fibromodulin in inflammatory responses and diseases associated with inflammation

Inflammation is an immune response that the host organism eliminates threats from foreign objects or endogenous signals. It plays a key role in the progression, prognosis as well as therapy of diseases. Chronic inflammatory diseases have been regarded as the main cause of death worldwide at present, which greatly affect a vast number of individuals, producing economic and social burdens. Thus, developing drugs targeting inflammation has become necessary and attractive in the world. Currently, accumulating evidence suggests that small leucine-rich proteoglycans (SLRPs) exhibit essential roles in various inflammatory responses by acting as an anti-inflammatory or pro-inflammatory role in different scenarios of diseases. Of particular interest was a well-studied member, termed fibromodulin (FMOD), which has been largely explored in the role of inflammatory responses in inflammatory-related diseases. In this review, particular focus is given to the role of FMOD in inflammatory response including the relationship of FMOD with the complement system and immune cells, as well as the role of FMOD in the diseases associated with inflammation, such as skin wounding healing, osteoarthritis (OA), tendinopathy, atherosclerosis, and heart failure (HF). By conducting this review, we intend to gain insight into the role of FMOD in inflammation, which may open the way for the development of new anti-inflammation drugs in the scenarios of different inflammatory-related diseases.

E3 ligase HECTD3 promotes RNA virus replication and virus-induced inflammation via K33-linked polyubiquitination of PKR

Uncontrolled viral replication and excessive inflammation are the main causes of death in the host infected with virus. Hence inhibition of intracellular viral replication and production of innate cytokines, which are the key strategies of hosts to fight virus infections, need to be finely tuned to eliminate viruses while avoid harmful inflammation. The E3 ligases in regulating virus replication and subsequent innate cytokines production remain to be fully characterized. Here we report that the deficiency of the E3 ubiquitin-protein ligase HECTD3 results in accelerated RNA virus clearance and reduced inflammatory response both in vitro and in vivo. Mechanistically, HECTD3 interacts with dsRNA-dependent protein kinase R (PKR) and mediates Lys33-linkage of PKR, which is the first non-proteolytic ubiquitin modification for PKR. This process disrupts the dimerization and phosphorylation of PKR and subsequent EIF2α activation, which results in the acceleration of virus replication, but promotes the formation of PKR-IKK complex and subsequent inflammatory response. The finding suggests HECTD3 is the potential therapeutic target for simultaneously restraining RNA virus replication and virus-induced inflammation once pharmacologically inhibited.

T cells, NK cells, and tumor-associated macrophages in cancer immunotherapy and the current state of the art of drug delivery systems

The immune system provides full protection for the body by specifically identifying 'self' and removing 'others'; thus protecting the body from diseases. The immune system includes innate immunity and adaptive immunity, which jointly coordinate the antitumor immune response. T cells, natural killer (NK) cells and tumor-associated macrophages (TAMs) are the main tumor-killing immune cells active in three antitumor immune cycle. Cancer immunotherapy focusses on activating and strengthening immune response or eliminating suppression from tumor cells in each step of the cancer-immunity cycle; thus, it strengthens the body's immunity against tumors. In this review, the antitumor immune cycles of T cells, natural killer (NK) cells and tumor-associated macrophages (TAMs) are discussed. Co-stimulatory and co-inhibitory molecules in the three activity cycles and the development of drugs and delivery systems targeting these molecules are emphasized, and the current state of the art of drug delivery systems for cancer immunotherapy are summarized.

The immunomodulatory function and antitumor effect of disulfiram: paving the way for novel cancer therapeutics

More than 60 years ago, disulfiram (DSF) was employed for the management of alcohol addiction. This promising cancer therapeutic agent inhibits proliferation, migration, and invasion of malignant tumor cells. Furthermore, divalent copper ions can enhance the antitumor effects of DSF. Molecular structure, pharmacokinetics, signaling pathways, mechanisms of action and current clinical results of DSF are summarized here. Additionally, our attention is directed towards the immunomodulatory properties of DSF and we explore novel administration methods that may address the limitations associated with antitumor treatments based on DSF. Despite the promising potential of these various delivery methods for utilizing DSF as an effective anticancer agent, further investigation is essential in order to extensively evaluate the safety and efficacy of these delivery systems.

Regulation of PKR-dependent RNA translation inhibition by TRIM21 upon virus infection or other stress

The host always employs various ways to defend against viral infection and spread. However, viruses have evolved their own effective strategies, such as inhibition of RNA translation of the antiviral effectors, to destroy the host's defense barriers. Protein synthesis, commonly controlled by the α-subunit of eukaryotic translation initiation factor 2 (eIF2α), is a basic cellular biological process among all species. In response to viral infection, in addition to inducing the transcription of antiviral cytokines by innate immunity, infected cells also inhibit the RNA translation of antiviral factors by activating the protein kinase R (PKR)-eIF2α signaling pathway. Regulation of innate immunity has been well studied; however, regulation of the PKR-eIF2α signaling pathway remains unclear. In this study, we found that the E3 ligase TRIM21 negatively regulates the PKR-eIF2α signaling pathway. Mechanistically, TRIM21 interacts with the PKR phosphatase PP1α and promotes K6-linked polyubiquitination of PP1α. Ubiquitinated PP1α augments its interaction with PKR, causing PKR dephosphorylation and subsequent translational inhibition release. Furthermore, TRIM21 can constitutively restrict viral infection by reversing PKR-dependent translational inhibition of various previously known and unknown antiviral factors. Our study highlights a previously undiscovered role of TRIM21 in regulating translation, which will provide new insights into the host antiviral response and novel targets for the treatment of translation-associated diseases in the clinic.

Expression profiling and antibacterial analysis of cd36 in mandarin fish, Siniperca chuatsi

Cd36 is classified as a class B scavenger receptor and has also been identified as a pattern recognition receptor. In this study, we investigated the genomic structure and molecular characteristics of cd36 in mandarin fish (Siniperca chuatsi), examined its tissue distribution, and evaluated its antibacterial activity. Genomic structure analysis showed that Sccd36 consists of 12 exons and 11 introns. Sequencing analysis confirmed that the open reading frame of Sccd36 contains 1410 bp, encoding 469 amino acids. Sccd36 is deeply conserved with other vertebrates in terms of genomic structure, gene loci and molecular evolution, and the feature of two transmembrane was observed in ScCd36 through structural prediction. Sccd36 was constitutively expressed in all tissues tested, with the strongest expression in the intestine, followed by the heart and the kidney. Dramatic changes of Sccd36 mRNA were detected in mucosal tissues, including the intestine, gill and skin, when stimulated by the microbial ligands lipopolysaccharide and lipoteichoic acid. In addition, ScCd36 was identified as having strong binding ability to microbial ligands and antibacterial activity against the gram-negative bacteria Aeromonas hydrophila and the gram-positive bacteria Streptococcus lactis. Furthermore, we verified that the genetic ablation of cd36 impaired the resistance of fish to bacterial challenge by using zebrafish cd36 knockout line. In conclusion, our findings suggest that ScCd36 plays a crucial role in the innate immune response of mandarin fish against bacterial infections. This also sets the stage for further exploration into the antibacterial function of Cd36 in lower vertebrate species.

Role of pyroptosis in the pathogenesis and treatment of diseases

Programmed cell death (PCD) is regarded as a pathological form of cell death with an intracellular program mediated, which plays a pivotal role in maintaining homeostasis and embryonic development. Pyroptosis is a new paradigm of PCD, which has received increasing attention due to its close association with immunity and disease. Pyroptosis is a form of inflammatory cell death mediated by gasdermin that promotes the release of proinflammatory cytokines and contents induced by inflammasome activation. Recently, increasing evidence in studies shows that pyroptosis has a crucial role in inflammatory conditions like cardiovascular diseases (CVDs), cancer, neurological diseases (NDs), and metabolic diseases (MDs), suggesting that targeting cell death is a potential intervention for the treatment of these inflammatory diseases. Based on this, the review aims to identify the molecular mechanisms and signaling pathways related to pyroptosis activation and summarizes the current insights into the complicated relationship between pyroptosis and multiple human inflammatory diseases (CVDs, cancer, NDs, and MDs). We also discuss a promising novel strategy and method for treating these inflammatory diseases by targeting pyroptosis and focus on the pyroptosis pathway application in clinics.

STING Promotes Intestinal IgA Production by Regulating Acetate-producing Bacteria to Maintain Host-microbiota Mutualism

BACKGROUND

Intestinal Immunoglobulin A (IgA) is crucial in maintaining host-microbiota mutualism and gut homeostasis. It has been shown that many species of gut bacteria produce cyclic dinucleotides, along with an abundance of microbiota-derived DNA present within the intestinal lumen, which triggers the tonic activation of the cytosolic cGAS-STING pathway. However, the role of STING in intestinal IgA remains poorly understood. We further investigated whether and how STING affects intestinal IgA response.

METHODS

Intestinal IgA was determined between wild-type (WT) mice and Sting-/- mice in steady conditions and upon enteric Citrobacter rodentium infection. STING agonists were used to stimulating B cells or dendritic cells in vitro. Gut microbiota composition was examined by 16S ribosomal RNA gene sequencing. Bacteria metabolomics functional analyses was performed by PICRUSt2. Fecal short-chain fatty acid (SCFA) was determined by Mass spectrometry and Cedex Bio Analyzer. Gut bacteria from WT mice and Sting-/- mice were transferred into germ-free mice and antibiotic-pretreated mice.

RESULTS

Intestinal IgA response was impaired in Sting-/- mice. However, STING agonists did not directly stimulate B cells or dendritic cells to induce IgA. Interestingly, Sting-/- mice displayed altered gut microbiota composition with decreased SCFA-producing bacteria and downregulated SCFA fermentation pathways. Transfer of fecal bacteria from Sting-/- mice induced less IgA than that from WT mice in germ-free mice and antibiotic-pretreated mice, which is mediated by GPR43. Acetate, the dominant SCFA, was decreased in Sting-/- mice, and supplementation of acetate restored intestinal IgA production in Sting-/- mice.

CONCLUSIONS

STING promotes intestinal IgA by regulating acetate-producing gut bacteria.

Interferon and autoantigens: intersection in autoimmunity

Interferon (IFN) is a key component of the innate immune response. For reasons that remain incompletely understood, the IFN system is upregulated in several rheumatic diseases, particularly those that feature autoantibody production, such as SLE, Sjögren's syndrome, myositis and systemic sclerosis. Interestingly, many of the autoantigens targeted in these diseases are components of the IFN system, representing IFN-stimulated genes (ISGs), pattern recognition receptors (PRRs), and modulators of the IFN response. In this review, we describe features of these IFN-linked proteins that may underlie their status as autoantigens. Note is also made of anti-IFN autoantibodies that have been described in immunodeficiency states.

Deubiquitinase USP47 attenuates virus-induced type I interferon signaling

The innate immune responses are tightly regulated to ensure effective clearance of invading pathogens and avoid excessive inflammation. Ubiquitination and deubiquitination are important post-translational modifications in antiviral immune responses. Here, we discovered deubiquitinase USP47 as a novel negative immune system regulator. Overexpression of USP47 repressed Sendai virus, poly(I:C) and poly(dA:dT)-induced ISRE and IFN-β activation, along with reduced IFNB1 transcription and enhanced viral replication. Knockdown of USP47 expression had the opposite effects. Dual-luciferase and phosphorylation assays showed that USP47 targeted downstream of MAVS and upstream of TBK1. Additional co-immunoprecipitation assays suggested that USP47 interacted with TRAF3 and TRAF6. Importantly, USP47 removed K63-linked polyubiquitin chains from TRAF3 and TRAF6. Hence, we describe a novel modulator of the antiviral innate immune response, USP47, which removes K63-linked polyubiquitins from TRAF3 and TRAF6, leading to reduced type I IFN signaling.

Pathogen Recognition-Driven Dendritic Cell-Specific Gene Silencing and Editing

Dendritic cells (DCs) play an essential role in both the induction of the immune response and the maintenance of immune tolerance, with any malfunction of DCs potentially causing several diseases. While gene-based therapy for DC manipulation is a promising approach, it remains challenging due to the lack of efficient delivery systems for DC targeting. Herein, we describe a novel bacterial nanomedicine (BNM) system for pathogen recognition-mediated DCs-specific gene silencing and gene editing. BNMs contain components from bacterial outer membranes and achieve efficient DC targeting through the recognition of pathogen-associated molecular patterns by pattern recognition receptors on DCs. The targeting efficiency of BNMs is reduced in DCs lacking toll-like receptor 4, which is responsible for recognizing lipopolysaccharide, a major component of the bacterial outer membrane. As a proof-of-concept demonstration, we present gene-based therapy mediated by BNMs for enhancing antigen cross-presentation in DCs, which generates a remarkable antitumor effect.

Mitophagy, Inflammasomes and Their Interaction in Kidney Diseases: A Comprehensive Review of Experimental Studies

Mitophagy is an important mechanism for mitochondrial quality control by regulating autophagosome-specific phagocytosis, degradation and clearance of damaged mitochondria, and involved in cell damage and diseases. Inflammasomes are important inflammation-related factors newly discovered in recent years, which are involved in cell innate immunity and inflammatory response, and play an important role in kidney diseases. Based on the current studies, we reviewed the progress of mitophagy, inflammasomes and their interaction in kidney diseases.

IL-27p28 knockout aggravates Doxorubicin-induced cardiotoxicity by regulating Macrophage polarization

BACKGROUND

Several interleukins (ILs) have been demonstrated to participate in cardiac injury. This study aimed to investigate whether IL-27p28 plays a regulatory role in doxorubicin (DOX)-induced cardiac injury by regulating inflammation and oxidative stress.

METHODS

Dox was used to establish a mouse cardiac injury model, and IL-27p28 was knocked out to observe its role in cardiac injury. In addition, monocytes were adoptively transferred to clarify whether monocyte-macrophages mediate the regulatory role of IL-27p28 in DOX-induced cardiac injury.

RESULTS

IL-27p28 knockout significantly aggravated DOX-induced cardiac injury and cardiac dysfunction. IL-27p28 knockout also upregulated the phosphorylation levels of p65 and STAT1 and promoted M1 macrophage polarization in DOX-treated mice, which increased cardiac inflammation and oxidative stress. Moreover, IL-27p28-knockout mice that were adoptively transferred WT monocytes exhibited worse cardiac injury and cardiac dysfunction and higher cardiac inflammation and oxidative stress.

CONCLUSIONS

IL-27p28 knockdown aggravates DOX-induced cardiac injury by worsening the M1 macrophage/M2 macrophage imbalance and its associated inflammatory response and oxidative stress.

p120-catenin promotes innate antiviral immunity through stabilizing TBK1-IRF3 complex

TBK1-IRF3 complex plays vital roles in antiviral immune responses, its regulatory mechanisms are currently incompletely understood. p120-catenin (p120), an armadillo-repeat protein, mainly regulates the stability of classical cadherins and the development of epithelial-to-mesenchymal transitions (EMTs). Here we report that p120 is a positive regulator of type I IFN production. Ectopic expression of p120 enhanced Vesicular stomatitis virus and Sendai-virus-induced type I IFN production, whereas knockdown of p120 expression suppressed type I IFN production. Mechanistically, p120 promoted phosphorylation of IRF3 via stabilizing the TBK1-IRF3 complex. Consistently, p120 knock down mice are more susceptible to VSV infection as indicated by higher tissue viral titers, less IFN-I production and greater infiltration of immune cells. This study reveals p120 as an important positive regulator in innate immunity and identifies that p120 facilitates host antiviral response through stabilizing TBK1-IRF3 complex.

DNA Repair Deficiency Regulates Immunity Response in Cancers: Molecular Mechanism and Approaches for Combining Immunotherapy

Defects in DNA repair pathways can lead to genomic instability in multiple tumor types, which contributes to tumor immunogenicity. Inhibition of DNA damage response (DDR) has been reported to increase tumor susceptibility to anticancer immunotherapy. However, the interplay between DDR and the immune signaling pathways remains unclear. In this review, we will discuss how a deficiency in DDR affects anti-tumor immunity, highlighting the cGAS-STING axis as an important link. We will also review the clinical trials that combine DDR inhibition and immune-oncology treatments. A better understanding of these pathways will help exploit cancer immunotherapy and DDR pathways to improve treatment outcomes for various cancers.

Astragalus polysaccharides combined with simvastatin as an immunostimulant enhances the immune adjuvanticity of oil-in-water emulsion and immune responses in mice

Oil-in-water emulsion-based adjuvants have demonstrated acceptable safety in many disease indications, while their adjuvant activities for vaccines still need to be improved. Recently, the strategy of combining adjuvants with multiple types of immunostimulants has been shown to enhance immune responses. In this study, astragalus polysaccharides were combined with simvastatin as an immunostimulant to construct a compound O/W emulsion adjuvant. The formulations were optimized according to the OVA-specific antibody responses induced in mice. For this reason, high (5 mg/mL), medium (2.5 mg/mL), and low (1.25 mg/mL) concentrations of astragalus polysaccharides and high (10 mg/mL), medium (1 mg/mL), and low (0.1 mg/mL) concentrations of simvastatin were selected. The final optimal formulation of the immunostimulant was a high concentration of astragalus polysaccharides combined with a medium concentration of simvastatin. The optimal compound O/W emulsion adjuvant could induce effective humoral and cellular immune responses that were stronger and more stable than those induced by aluminum adjuvant and Freund's adjuvant. The OVA/HAPS-MSim-OE induced dramatically strong and persistent IgG expressions and Th1-polarized immune responses. What's more, the highest CD4⁺/CD8⁺lymphocyte ratios were observed in OVA/HAPS-MSim-OE group. In addition, compound O/W emulsion adjuvant groups significantly promoted the secretion of IFN-γ and IL-6, which also indicated that the compound O/W emulsion adjuvants could induce both enhanced Th1 and Th2-mediated immune responses but prefer the Th1-mediated ones. This study would contribute to an interesting and promising direction in the development of emulsion-based adjuvants.

Scavenger receptor BI attenuates oxidized phospholipid-induced pulmonary inflammation

Damage associated molecular patterns (DAMPs) are molecules released from dead/dying cells following toxicant and/or environmental exposures that activate the immune response through binding of pattern recognition receptors (PRRs). Excessive production of DAMPs or failed clearance leads to chronic inflammation and delayed inflammation resolution. One category of DAMPs are oxidized phospholipids (oxPLs) produced upon exposure to high levels of oxidative stress, such as following ozone (O3) induced inflammation. OxPLs are bound by multiple classes of PRRs that include scavenger receptors (SRs) such as SR class B-1 (SR-BI) and toll-like receptors (TLRs). Interactions between oxPLs and PRRs appear to regulate inflammation; however, the role of SR-BI in oxPL-induced lung inflammation has not been defined. Therefore, we hypothesize that SR-BI is critical in protecting the lung from oxPL-induced pulmonary inflammation/injury. To test this hypothesis, C57BL/6J (WT) female mice were dosed with oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphatidylcholine (oxPAPC) by oropharyngeal aspiration which increased pulmonary SR-BI expression. Following oxPAPC exposure, SR-BI deficient (SR-BI-/-) mice exhibited increased lung pathology and inflammatory cytokine/chemokine production. Lipidomic analysis revealed that SR-BI-/- mice had an altered pulmonary lipidome prior to and following oxPAPC exposure, which correlated with increased oxidized phosphatidylcholines (PCs). Finally, we characterized TLR4-mediated activation of NF-κB following oxPAPC exposure and discovered that SR-BI-/- mice had increased TLR4 mRNA expression in lung tissue and macrophages, increased nuclear p65, and decreased cytoplasmic IκBα. Overall, we conclude that SR-BI is required for limiting oxPAPC-induced lung pathology by maintaining lipid homeostasis, reducing oxidized PCs, and attenuating TLR4-NF-κB activation, thereby preventing excessive and persistent inflammation.

The Roles of TRAF3 in Immune Responses

Seven tumor necrosis factor receptor- (TNFR-) associated factors (TRAFs) have been found in mammals, which are primarily involved in the signal translation of the TNFR superfamily, the Toll-like receptor (TLR) family, and the retinoic acid-inducible gene I- (RIG-I-) like receptor (RLR) family. TRAF3 is one of the most diverse members of the TRAF family. It can positively regulate type I interferon production while negatively regulating signaling pathways of classical nuclear factor-κB, nonclassical nuclear factor-κB, and mitogen-activated protein kinase (MAPK). This review summarizes the roles of TRAF3 signaling and the related immune receptors (e.g., TLRs) in several preclinical and clinical diseases and focuses on the roles of TRAF3 in immune responses, the regulatory mechanisms, and its role in disease.

Therapeutic interventions target the NLRP3 inflammasome in ulcerative colitis: Comprehensive study

One of the significant health issues in the world is the prevalence of ulcerative colitis (UC). UC is a chronic disorder that mainly affects the colon, beginning with the rectum, and can progress from asymptomatic mild inflammation to extensive inflammation of the entire colon. Understanding the underlying molecular mechanisms of UC pathogenesis emphasizes the need for innovative therapeutic approaches based on identifying molecular targets. Interestingly, in response to cellular injury, the NLR family pyrin domain containing 3 (NLRP3) inflammasome is a crucial part of the inflammation and immunological reaction by promoting caspase-1 activation and the release of interleukin-1β. This review discusses the mechanisms of NLRP3 inflammasome activation by various signals and its regulation and impact on UC.

The prognostic value and response to immunotherapy of immunogenic cell death-associated genes in breast cancer

Breast cancer (BRCA) remains the most prevalent cancer worldwide and the tumor microenvironment (TME) has been discovered to exert a wide influence on the overall survival and therapeutic response. Numerous lines of evidence reported that the effects of immunotherapy of BRCA were manipulated by TME. Immunogenic cell death (ICD) is a form of regulated cell death (RCD) that is capable of fueling adaptive immune responses and aberrant expression of ICD-related genes (ICDRGs) can govern the TME system by emitting danger signals or damage-associated molecular patterns (DAMPs). In the current study, we obtained 34 key ICDRGs in BRCA. Subsequently, using the transcriptome data of BRCA from the TCGA database, we constructed a risk signature based on 6 vital ICDRGs, which had a good performance in predicting the overall survival of BRCA patients. We also examined the efficacy of our risk signature in the validation dataset (GSE20711) in the GEO database and it performed excellently. According to the risk model, patients with BRCA were divided into high-risk and low-risk groups. Also, the unique immune characteristics and TME between the two subgroups and 10 promising small molecule drugs targeting BRCA patients with different ICDRGs risk have been investigated. The low-risk group had good immunity indicated by T cell infiltration and high immune checkpoint expression. Moreover, the BRCA samples could be divided into three immune subtypes according to immune response severity (ISA, ISB, and ISC). ISA and ISB predominated in the low-risk group and patients in the low-risk group exhibited a more vigorous immune response. In conclusion, we developed an ICDRGs-based risk signature that can predict the prognosis of BRCA patients and offer a novel therapeutic strategy for immunotherapy, which would be of great significance in the BRCA clinical setting.

Immunity of turbot Induced by inactivated vaccine of Aeromonas salmonicida from the perspective of DNA methylation

Introduction

DNA methylation was one of the most important modification in epigenetics and played an important role in immune response. Since the introduction of Scophthalmus maximus, the scale of breeding has continued to expand, during which diseases caused by various bacteria, viruses and parasites have become increasingly serious. Therefore, the inactivated vaccines have been widely researched and used in the field of aquatic products with its unique advantages. However, the immune mechanism that occurred in turbot after immunization with inactivated vaccine of Aeromonas salmonicida was not clear.

Methods

In this study, differentially methylated regions (DMRs) were screened by Whole Genome Bisulfite Sequencing (WGBS) and significantly differentially expressed genes (DEGs) were screened by Transcriptome sequencing. Double luciferase report assay and DNA pull-down assay were further verified the DNA methylation state of the gene promoter region affected genes transcriptional activity after immunization with inactivated vaccine of Aeromonas salmonicida.

Results

A total of 8149 differentially methylated regions (DMRs) were screened, in which there were many immune-related genes with altered DNA methylation status. Meanwhile, 386 significantly differentially expressed genes (DEGs) were identified, many of which were significantly enriched in Toll-like receptor signaling pathway, NOD-like receptor signaling pathway and C-type lectin receptor signaling pathway. Combined analysis of WGBS results and RNA-seq results, a total of 9 DMRs of negatively regulated genes are located in the promoter region, including 2 hypermethylated genes with lower expression and 7 hypomethylated genes with higher expression. Then, two immune-related genes C5a anaphylatoxin chemotactic receptor 1-like (C5ar1-Like) and Eosinophil peroxidase-like (EPX-Like), were screened to explore the regulation mechanism of DNA methylation modification on their expression level. Moreover, the DNA methylation state of the gene promoter region affected genes transcriptional activity by inhibiting the binding of transcription factors, which lead to changes in the expression level of the gene.

Discussion

We jointly analyzed WGBS and RNA-seq results and revealed the immune mechanism that occurred in turbot after immunized with inactivated vaccine of A. salmonicida from the perspective of DNA methylation.

Regulation of immunological tolerance by the p53-inhibitor iASPP

Maintenance of immunological homeostasis between tolerance and autoimmunity is essential for the prevention of human diseases ranging from autoimmune disease to cancer. Accumulating evidence suggests that p53 can mitigate phagocytosis-induced adjuvanticity thereby promoting immunological tolerance following programmed cell death. Here we identify Inhibitor of Apoptosis Stimulating p53 Protein (iASPP), a negative regulator of p53 transcriptional activity, as a regulator of immunological tolerance. iASPP-deficiency promoted lung adenocarcinoma and pancreatic cancer tumorigenesis, while iASPP-deficient mice were less susceptible to autoimmune disease. Immune responses to iASPP-deficient tumors exhibited hallmarks of immunosuppression, including activated regulatory T cells and exhausted CD8+ T cells. Interestingly, iASPP-deficient tumor cells and tumor-infiltrating myeloid cells, CD4+, and γδ T cells expressed elevated levels of PD-1H, a recently identified transcriptional target of p53 that promotes tolerogenic phagocytosis. Identification of an iASPP/p53 axis of immune homeostasis provides a therapeutic opportunity for both autoimmune disease and cancer.

CgDM9CP-5-Integrin-MAPK Pathway Regulates the Production of CgIL-17s and Cgdefensins in the Pacific Oyster, Crassostrea gigas

DM9 domain containing protein (DM9CP) is a family of newly identified recognition receptors exiting in most organisms except plants and mammals. In the current study, to our knowledge, a novel DM9CP-5 (CgDM9CP-5) with two tandem DM9 repeats and high expression level in gill was identified from the Pacific oyster, Crassostrea gigas. The deduced amino acid sequence of CgDM9CP-5 shared 62.1% identity with CgDM9CP-1 from C. gigas, and 47.8% identity with OeFAMeT from Ostrea edulis. The recombinant CgDM9CP-5 (rCgDM9CP-5) was able to bind d-mannose, LPS, peptidoglycan, and polyinosinic-polycytidylic acid, as well as fungi Pichia pastoris, Gram-negative bacteria Escherichia coli and Vibrio splendidus, and Gram-positive bacteria Staphylococcus aureus. The mRNA transcript of CgDM9CP-5 was highly expressed in gill, and its protein was mainly distributed in gill mucus. After the stimulations with V. splendidus and mannose, mRNA expression of CgDM9CP-5 in oyster gill was significantly upregulated and reached the peak level at 6 and 24 h, which was 13.58-fold (p < 0.05) and 14.01-fold (p < 0.05) of that in the control group, respectively. CgDM9CP-5 was able to bind CgIntegrin both in vivo and in vitro. After CgDM9CP-5 or CgIntegrin was knocked down by RNA interference, the phosphorylation levels of JNK and P38 in the MAPK pathway decreased, and the expression levels of CgIL-17s (CgIL-17-3, -4, -5, and -6), Cg-Defh1, Cg-Defh2, and CgMolluscidin were significantly downregulated. These results suggested that there was a pathway of DM9CP-5-Integrin-MAPK mediated by CgDM9CP-5 to regulate the release of proinflammatory factors and defensins in C. gigas.

RBP-RNA interactions in the control of autoimmunity and autoinflammation

Autoimmunity and autoinflammation arise from aberrant immunological and inflammatory responses toward self-components, contributing to various autoimmune diseases and autoinflammatory diseases. RNA-binding proteins (RBPs) are essential for immune cell development and function, mainly via exerting post-transcriptional regulation of RNA metabolism and function. Functional dysregulation of RBPs and abnormities in RNA metabolism are closely associated with multiple autoimmune or autoinflammatory disorders. Distinct RBPs play critical roles in aberrant autoreactive inflammatory responses via orchestrating a complex regulatory network consisting of DNAs, RNAs and proteins within immune cells. In-depth characterizations of RBP-RNA interactomes during autoimmunity and autoinflammation will lead to a better understanding of autoimmune pathogenesis and facilitate the development of effective therapeutic strategies. In this review, we summarize and discuss the functions of RBP-RNA interactions in controlling aberrant autoimmune inflammation and their potential as biomarkers and therapeutic targets.

Emerging role of microbiota derived outer membrane vesicles to preventive, therapeutic and diagnostic proposes

The role of gut microbiota and its products in human health and disease is profoundly investigated. The communication between gut microbiota and the host involves a complicated network of signaling pathways via biologically active molecules generated by intestinal microbiota. Some of these molecules could be assembled within nanoparticles known as outer membrane vesicles (OMVs). Recent studies propose that OMVs play a critical role in shaping immune responses, including homeostasis and acute inflammatory responses. Moreover, these OMVs have an immense capacity to be applied in medical research, such as OMV-based vaccines and drug delivery. This review presents a comprehensive overview of emerging knowledge about biogenesis, the role, and application of these bacterial-derived OMVs, including OMV-based vaccines, OMV adjuvants characteristics, OMV vehicles (in conjugated vaccines), cancer immunotherapy, and drug carriers and delivery systems. Moreover, we also highlight the significance of the potential role of these OMVs in diagnosis and therapy.

Inhibition of Serum- and Glucocorticoid-Regulated Protein Kinase-1 Aggravates Imiquimod-Induced Psoriatic Dermatitis and Enhances Proinflammatory Cytokine Expression through the NF-kB Pathway

Although the anti-inflammatory effect of serum- and glucocorticoid-regulated protein kinase 1 (SGK1) has been established in other diseases, the possible regulatory role of SGK1 in psoriasis and the underlying molecular mechanisms remain largely unknown. In this study, we found that SGK1 expression was decreased in macrophages from patients with psoriasis. Moreover, a specific pharmacological SGK1 inhibitor, EMD638683, significantly enhanced imiquimod-mediated toll-like receptor 7/8 activity and proinflammatory cytokine production in RAW264.7 cells, and this result was confirmed by Sgk1 small interfering RNA. Further mechanistic data showed that SGK1 inhibition increased the phosphorylation of Bruton's agammaglobulinemia tyrosine kinase; moreover, Bruton's agammaglobulinemia tyrosine kinase inhibition abrogated the proinflammatory effects of the SGK1 inhibitor on toll-like receptor 7/8 activation, thereby validating that SGK1 inhibition enhances the toll-like receptor 7/8 pathway by increasing Bruton's agammaglobulinemia tyrosine kinase phosphorylation. In addition, our in vivo results showed that SGK1 inhibition significantly increased the secretion of proinflammatory cytokines, including IL-1β, IL-6, and TNF-α, and the infiltration of T helper 17 cells in an imiquimod-induced psoriasis mouse model. Altogether, these results show that SGK1 plays a critical role in the pathogenesis of psoriasis by modulating inflammatory responses in skin lesions, indicating that SGK1‒Bruton's agammaglobulinemia tyrosine kinase signaling could be a novel therapeutic target for the control of psoriasis.

Clinical Value of Glycan Changes in Cerebrospinal Fluid for Evaluation of Post-Neurosurgical Bacterial Meningitis with Hemorrhagic Stroke Patients

Post-neurosurgical bacterial meningitis (PNBM) is one of the severe complications in patients receiving neurosurgical procedures. Recent studies have found microbe-related glycans play important roles in adhesion, invasion, and toxicity toward innate immunological reactions. In this study, we aimed to investigate the glycomic profile and its potential diagnostic efficacy in post-neurosurgical bacterial meningitis (PNBM) patients with hemorrhagic stroke. A total of 136 cerebrospinal fluid (CSF) samples were recruited and divided into a PNBM group and a non-PNBM group based on the clinical diagnostic criteria. A lectin biochip-based method was established for the detection of glycans in CSF. The clinicopathological data and biochemical parameters in CSF from all patients were analyzed. Two models for multivariate analysis investigating glycan changes in the CSF were conducted, aiming at determining the specific expression and diagnostic efficacy of lectin-probing glycans (LPGs) for PNBM. In univariate analysis, we found that 8 out of 11 LPGs were significantly correlated with PNBM. Model 1 multivariate analysis revealed that PNA (p = 0.034), Jacalin (p = 0.034) and LTL (p = 0.001) were differentially expressed in the CSF of PNBM patients compared with those of non-PNBM patients. Model 2 multivariate analysis further disclosed that LTL (p = 0.021) and CSF glucose (p < 0.001) had independent diagnostic efficacies in PNBM, with areas under the curve (AUC) of 0.703 and 0.922, respectively. In summary, this study provided a new insight into the subject of CSF glycomics concerning bacterial infection in patients with hemorrhagic stroke.

Atorvastatin-induced tolerogenic dendritic cells improve cardiac remodeling by suppressing TLR-4/NF-κB activation after myocardial infarction

OBJECTIVE

Myocardial infarction (MI) caused by ischemic cardiomyocyte necrosis induces inflammatory responses that strongly affect ventricular remodeling. Tolerogenic dendritic cells (tDCs) can suppress this effect on inflammatory responses. However, the precise role of atorvastatin-induced tDCs in ventricular remodeling after MI remains unclear.

METHODS

To explore the effect of necrotic cardiomyocytes (SNC) and/or atorvastatin on DC function, the expression of CD40, CD80, CD86, and MHC-II was determined using flow cytometry. The protein levels of TLR-4/NF-κB-related molecules were evaluated using western blotting. The infarct area after MI was determined via 2,3,5-triphenyltetrazolium chloride staining. The TUNEL assay was employed to evaluate the apoptosis of cardiomyocytes in heart sections. Masson's trichrome method was used to determine the extent of fibrosis.

RESULTS

Compared to the DCs co-cultured with PBS (control), cells co-cultured with Supernatant-IM or Supernatant-NH produced higher levels of inflammatory cytokines, including TNF-α, IL-1, IL-6, IL-12P40, and IL-8. This cytokine production was impaired by atorvastatin treatment. SNC treatment induced DC maturation and enhanced inflammatory cytokine secretion and oxidative stress through TLR-4/NF-κB pathway activation. Compared to that in the PBS-treated group, the left ventricular ejection fraction was significantly improved after tDC treatment. Additionally, compared to that in the PBS-treated group, tDC treatment reduced the left ventricular end-diastolic and end-systolic diameters in mice. Furthermore, treatment with tDCs improved the left ventricular systolic function, attenuated inflammatory cell infiltration, and reduced cardiomyocyte apoptosis, myocardial fibrosis, and infarct size compared to those in the control group.

CONCLUSIONS

Adoptive transfer of atorvastatin-induced tDCs alleviated post-infarction cardiomyocyte apoptosis and myocardial fibrosis in association with decreased inflammatory cell infiltration and inhibited oxidative stress, likely by suppressing TLR-4/NF-κB activation after myocardial infarction.

TRIM31: A molecule with a dual role in cancer

Tripartite motif (TRIM) 31 is a new member of the TRIM family and functions as an E3 ubiquitin ligase. Abnormal TRIM31 expression leads to a variety of pathological conditions, such as cancer, innate immunity diseases, sepsis-induced myocardial dysfunction, cerebral ischemic injury, nonalcoholic fatty liver disease and hypertensive nephropathy. In this review, we comprehensively overview the structure, expression and regulation of TRIM31 in cancer. Moreover, we discuss the dual role of TRIM31 in human cancer, and this dual role may be linked to its involvement in the selective regulation of several pivotal cellular signaling pathways: the p53 tumor suppressor, mTORC1, PI3K-AKT, NF-κB and Wnt/β-catenin pathways. In addition, we also discuss the emerging role of TRIM31 in innate immunity, autophagy and its growing sphere of influence across multiple human pathologies. Finally, a better understanding of the dual role of TRIM31 in cancer may provide new therapeutic strategies aimed at inhibiting the cancer-promoting effects of TRIM31 without affecting its tumor suppressor effects.

Degradation of HDAC10 by autophagy promotes IRF3-mediated antiviral innate immune responses

Histone deacetylases (HDACs) play important roles in immunity and inflammation. Through functional screening, we identified HDAC10 as an inhibitor of the type I interferon (IFN) response mediated by interferon regulatory factor 3 (IRF3). HDAC10 abundance was decreased in mouse macrophages in response to innate immune stimuli and was reduced in peripheral blood mononuclear cells (PBMCs) from patients with systemic lupus erythematosus (SLE) compared with that in PBMCs from healthy donors. Deficiency in HDAC10 in mouse embryonic fibroblasts and in mice promoted the expression of genes encoding type I IFNs and of IFN-stimulated genes (ISGs), leading to enhanced antiviral responses in vitro and in vivo. HDAC10 bound in a deacetylase-independent manner to IRF3 in uninfected cells to inhibit the phosphorylation of IRF3 at Ser³⁹⁶ by TANK-binding kinase 1 (TBK1). Upon viral infection, HDAC10 was targeted for autophagy-mediated degradation through its interaction with LC3-II. Consequently, IRF3 phosphorylation was increased, which resulted in enhanced type I IFN production and antiviral responses. Our findings identify a potential target for improving host defense responses against pathogen infection and for treating autoimmune disease.

The cGAS-STING-autophagy pathway: Novel perspectives in neurotoxicity induced by manganese exposure

Chronic high-level heavy metal exposure increases the risk of developing different neurodegenerative diseases. Chronic excessive manganese (Mn) exposure is known to lead to neurodegenerative diseases. In addition, some evidence suggests that autophagy dysfunction plays an important role in the pathogenesis of various neurodegenerative diseases. Over the past decade, the DNA-sensing receptor cyclic GMP-AMP synthase (cGAS) and its downstream signal-efficient interferon gene stimulator (STING), as well as the molecular composition and regulatory mechanisms of this pathway have been well understood. The cGAS-STING pathway has emerged as a crucial mechanism to induce effective innate immune responses by inducing type I interferons in mammalian cells. Moreover, recent studies have found that Mn²⁺ is the second activator of the cGAS-STING pathway besides dsDNA, and inducing autophagy is a primitive function for the activation of the cGAS-STING pathway. However, overactivation of the immune response can lead to tissue damage. This review discusses the mechanism of neurotoxicity induced by Mn exposure from the cGAS-STING-autophagy pathway. Future work exploiting the cGAS-STING-autophagy pathway may provide a novel perspective for manganese neurotoxicity.

The impact of Hyssop (Hyssopus officinalis) extract on activation of endosomal toll like receptors and their downstream signaling pathways

OBJECTIVES

From the ancient, medicinal benefits of Hyssop (Hyssopus officinalis L.) have been implicated for respiratory and digestive diseases despite the effects of Hyssop on viral infections have not been mechanistically investigated. In this study, we examined whether the Hyssop extract activated anti-viral innate immunity, as a sentinel for immune system, through activation of endosomal TLRs recognizing nucleic acids and their downstream signaling. The Hyssop herb extracts was prepared and co-cultured with healthy individual's peripheral blood mononuclear cells (PBMCs). After viability assay, gene expression levels of TLR3,7,8,9, as well as MyD88 and NF-κB, were evaluated in treated PBMCs using Real-time PCR. Next, the secretion level of immune related cytokines was quantified via ELISA.

RESULTS

Post 24 h, 40 µg/ml of the extract significantly inhibited the viability of less than 50% of cells compared to the control and had a maximum effect on cellular function. The Hyssop-treated PBMCs demonstrated an elevated expression of endosomal TLRs genes, as well as MyD88 and NF-κB. Moreover, the release of INF-α and β notably enhanced in cell culture supernatant, while the content of inflammatory cytokines remarkably diminished (P < 0.05). The Hyssop extract was capable of inducing antiviral innate immune responses so can be promising in antiviral drug strategies.

Tim-4 reprograms cholesterol metabolism to suppress antiviral innate immunity by disturbing the Insig1-SCAP interaction in macrophages

Accumulating evidence indicates that macrophages reshape their cholesterol metabolism in response to pathogens to support host defense. Intervention of host cholesterol homeostasis has emerged as a promising strategy for antiviral therapy. T cell immunoglobulin and mucin domain-containing molecule 4 (Tim-4) is indispensable in maintaining the homeostasis of macrophages. However, its role in antiviral innate immunity and cholesterol metabolism remains unknown. Here, we report that Tim-4 deficiency results in boosted interferon (IFN) signaling and decreased viral load. Mechanistically, Tim-4 disturbs the Insig1-SCAP interaction and promotes SCAP-SREBP2 complex translocation to the Golgi apparatus, eventually leading to the upregulation of cholesterol biosynthesis in macrophages, which limits the type I IFN response. Our findings demonstrate that Tim-4 suppresses type I IFN signaling by enhancing SREBP2 activation, delineating the role of Tim-4 in antiviral innate immunity and cholesterol metabolism, which sheds light on the mechanism by which Tim-4 orchestrates macrophage homeostasis.

A novel serum spherical lectin from lamprey reveals a more efficient mechanism of immune initiation and regulation in jawless vertebrates

The innate immune system is the body's first line of defense against pathogens and involves antibody and complement system-mediated antigen removal. Immune-response-related complement molecules have been identified in lamprey, and the occurrence of innate immune response via the mannose-binding lectin-associated serine proteases of the lectin cascade has been reported. We have previously shown that lamprey (Lampetra japonica) serum can efficiently and specifically eliminate foreign pathogens. Therefore, we aimed to understand the immune mechanism of lamprey serum in this study. We identified and purified a novel spherical lectin (LSSL) from lamprey serum. LSSL had two structural calcium ions coordinated with conserved amino acids, as determined through cryogenic electron microscopy. LSSL showed high binding capacity with microbial and mammalian glycans and demonstrated agglutination activity against bacteria. Phylogenetic analysis revealed that LSSL was transferred from phage transposons to the lamprey genome via horizontal gene transfer. Furthermore, LSSL was associated with mannose-binding lectin-associated serine protease 1 and promoted the deposition of the C3 fragment on the surface of target cells upon binding. These results led us to conclude that LSSL initiates and regulates agglutination, resulting in exogenous pathogen and tumor cell eradication. Our observations will give a greater understanding of the origin and evolution of the complement system in higher vertebrates and lead to the identification of novel immune molecules and pathways for defense against pathogens and tumor cells.

Ring Finger Protein 215 Negatively Regulates Type I IFN Production via Blocking NF-κB p65 Activation

Germline-encoded pattern recognition receptors (PRRs) recognize molecules frequently found in pathogens (pathogen-associated molecular patterns [PAMPs]) during viral infection. This process induces production of IFNs, leading to expression of IFN-stimulated genes to establish a cellular antiviral state against viral infection. However, aberrant activation of the IFN system may cause immunopathological damage and systemic autoimmune diseases such as systemic lupus erythematosus. Stringent control of IFN signaling activation is critical for maintaining homoeostasis of the immune system; yet, the mechanisms responsible for its precise regulation remain to be elucidated. In this study, we identified that ring finger protein 215 (RNF215), a zinc finger protein, was upregulated by viral infection in human macrophages. In addition, we demonstrated that RNF215 inhibited the production of type I IFNs at least in part via interacting with p65, a subunit of NF-κB, and repressed the accumulation of NF-κB in the promoter region of IFNB1. Moreover, we found that the expression of RNF215 negatively correlated with type I IFNs in patients with systemic lupus erythematosus, indicating that RNF215 plays an important role in the pathogenesis of autoimmune diseases. Collectively, our data identified RNF215 as a key negative regulator of type I IFNs and suggested RNF215 as a potential target for intervention in diseases with aberrant IFN production.

Self-Assembly of Immune Signals to Program Innate Immunity through Rational Adjuvant Design

Recent clinical studies show activating multiple innate immune pathways drives robust responses in infection and cancer. Biomaterials offer useful features to deliver multiple cargos, but add translational complexity and intrinsic immune signatures that complicate rational design. Here a modular adjuvant platform is created using self-assembly to build nanostructured capsules comprised entirely of antigens and multiple classes of toll-like receptor agonists (TLRas). These assemblies sequester TLR to endolysosomes, allowing programmable control over the relative signaling levels transduced through these receptors. Strikingly, this combinatorial control of innate signaling can generate divergent antigen-specific responses against a particular antigen. These assemblies drive reorganization of lymph node stroma to a pro-immune microenvironment, expanding antigen-specific T cells. Excitingly, assemblies built from antigen and multiple TLRas enhance T cell function and antitumor efficacy compared to ad-mixed formulations or capsules with a single TLRa. Finally, capsules built from a clinically relevant human melanoma antigen and up to three TLRa classes enable simultaneous control of signal transduction across each pathway. This creates a facile adjuvant design platform to tailor signaling for vaccines and immunotherapies without using carrier components. The modular nature supports precision juxtaposition of antigen with agonists relevant for several innate receptor families, such as toll, STING, NOD, and RIG.

Subgenomic RNAs and Their Encoded Proteins Contribute to the Rapid Duplication of SARS-CoV-2 and COVID-19 Progression

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently widespread throughout the world, accompanied by a rising number of people infected and breakthrough infection of variants, which make the virus highly transmissible and replicable. A comprehensive understanding of the molecular virological events and induced immunological features during SARS-CoV-2 replication can provide reliable targets for vaccine and drug development. Among the potential targets, subgenomic RNAs and their encoded proteins involved in the life cycle of SARS-CoV-2 are extremely important in viral duplication and pathogenesis. Subgenomic RNAs employ a range of coping strategies to evade immune surveillance from replication to translation, which allows RNAs to synthesize quickly, encode structural proteins efficiently and complete the entire process of virus replication and assembly successfully. This review focuses on the characteristics and functions of SARS-CoV-2 subgenomic RNAs and their encoded proteins and explores in depth the role of subgenomic RNAs in the replication and infection of host cells to provide important clues to the mechanism of COVID-19 pathogenesis.

The Global research of protein post-translational modifications in the cancer field: A bibliometric and visualized study

Objectives

Protein post-translational modifications (PTMs) are closely associated with tumorigenesis, targeting PTMs of key proteins might be the focus of antitumor drug discovery. This study aimed to analyze the research progress on protein PTMs in tumorigenesis by performing qualitative and quantitative evaluations.

Methods

The Web of Science Core Collection was selected as the database, and Science Citation Index Expanded was selected as the citation index. Visualization tools such as VOSviewer, CiteSpace, HistCite, and Online Analysis Platform of Bibliometrics were used to deeply explore the information of the retrieved research papers and analyze them in terms of research trends and main aspects of research.

Results

The search yielded 3777 relevant articles. The results showed that the total number of PTMs related papers in cancer field has been increasing annually, with the largest number of papers published in the United States of America. The co-word cluster analysis showed that the research on PTMs and tumorigenesis was primarily focused on the following four areas, mechanism, histone, P53, key Technologies. Tumor metabolism, autophagy, and protein-protein interaction, histone ubiquitination have become new research topics.

Conclusion

This study provides an important reference for the research direction and selection of topics of interest in the PTMs of cancer field.

Recent Advances in Delivery Systems for Genetic and Other Novel Vaccines

Vaccination is one of the most successful and cost-effective prophylactic measures against diseases, especially infectious diseases including smallpox and polio. However, the development of effective prophylactic or therapeutic vaccines for other diseases such as cancer remains challenging. This is often due to the imprecise control of vaccine activity in vivo which leads to insufficient/inappropriate immune responses or short immune memory. The development of new vaccine types in recent decades has created the potential for improving the protective potency against these diseases. Genetic and subunit vaccines are two major categories of these emerging vaccines. Owing to their nature, they rely heavily on delivery systems with various functions, such as effective cargo protection, immunogenicity enhancement, targeted delivery, sustained release of antigens, selective activation of humoral and/or cellular immune responses against specific antigens, and reduced adverse effects. Therefore, vaccine delivery systems may significantly affect the final outcome of genetic and other novel vaccines and are vital for their development. This review introduces these studies based on their research emphasis on functional design or administration route optimization, presents recent progress, and discusses features of new vaccine delivery systems, providing an overview of this field.

Effect of glioma-derived immunoglobulin on biological function of glioma cells

INTRODUCTION

Glioma is the most common and most invasive primary central nervous system tumour, and it is urgent to develop new specific therapeutic targets. Studies have confirmed that epithelial-derived tumour cells promote tumour cell proliferation and metastasis by secreting a large number of immunoglobulins (Igs), but the role of tumour-derived Igs in glioma has never been reported.

METHODS

The Gene Expression Profiling Interactive Analysis and Chinese Glioma Genome Atlas databases were used to analyse the Ig transcription and its correlation with the prognosis of patients with glioma. Immunohistochemistry and immunofluorescence were used to detect the protein expression of IgG and IgM in the glioma tissues of patients and glioma cell lines. When IgG was knocked down by small interfering RNA or knocked out by CRISPR-Cas9, the function of proliferation and migration of glioma cells were analysed by CCK-8, clone formation, wound healing, and transwell assays. Changes in proteins and their phosphorylation in signalling pathways were detected by western blotting. The nude mouse subcutaneous tumour-bearing model was established to analyse the effect of IgG in vivo.

RESULTS

The transcriptional level of IgG was pretty high in glioma tissues and was positively correlated with high WHO grade, recurrence, and poor prognosis. The expression of IgG and IgM was found in tumour tissues and human glioma cell lines U87 and U251, and the main expression form was secreted. Decreased IgG inhibited the proliferation and migration of glioma cells. Knockout or knockdown of IgG downregulated the phosphorylation of the key molecules in the MAPK and PI3K/Akt pathway through the HGF/SF-Met or FAK/Src pathway. In vivo tumourigenesis mouse model confirmed that reduced IgG expression inhibited glioma growth.

CONCLUSION

Ig was expressed in glioma tissues and cell lines, and a high expression level predicted a poor prognosis of patients. Glioma-derived IgG promoted glioma cell proliferation and migration through the HGF/SF-Met or FAK/Src pathway.

An overview of quantum dots-induced immunotoxicity and the underlying mechanisms

Quantum dots (QDs) have bright luminescence and excellent photostability. New synthesis techniques and strategies also enhance QDs properties for specific applications. With the continuous expansion of the applications, QDs-mediated immunotoxicity has become a major concern. The immune system has been confirmed to be an important target organ of QDs and is sensitive to QDs. Herein, review immunotoxic effects caused by QDs and the underlying mechanisms. Firstly, QDs exposure-induced modulation in immune cell maturation and differentiation is summarized, especially pre-exposed dendritic cells (DCs) and their regulatory roles in adaptive immunity. Cytokines are usually recognized as biomarkers of immunotoxicity, therefore, variation of cytokines mediated by QDs is also highlighted. Moreover, the activation of the complement system induced by QDs is discussed. Accumulated results have suggested that QDs disrupt the immune response by regulating intracellular oxidative stress (reactive oxygen species) levels, autophagy formation, and expressions of pro-inflammatory mediators. Furthermore, several signalling pathways play a key role in the disruption. Finally, some difficulties worthy of further consideration are proposed. Because there are still challenges in biomedical and clinical applications, this review hopes to provide information that could be useful in exploring the mechanisms associated with QD-induced immunotoxicity.

Mouse Ocilrp2/Clec2i negatively regulates LPS-mediated IL-6 production by blocking Dap12-Syk interaction in macrophage

C-type lectin Ocilrp2/Clec2i is widely expressed in dendritic cells, lymphokine-activated killer cells and activated T cells. Previous studies have shown that Ocilrp2 is an important regulator in the activation of T cells and NK cells. However, the role of Ocilrp2 in the inflammatory responses by activated macrophages is currently unknown. This study investigated the expression of inflammatory cytokines in LPS-induced macrophages from primary peritoneal macrophages silenced by specific siRNA target Ocilrp2. Ocilrp2 was significantly downregulated in macrophages via NF-κB and pathways upon LPS stimuli or VSV infection. Silencing Ocilrp2 resulted in the increased expression of IL-6 in LPS-stimulated peritoneal macrophages and mice. Moreover, IL-6 expression was reduced in LPS-induced Ocilrp2 over-expressing iBMDM cells. Furthermore, we found that Ocilrp2-related Syk activation is responsible for expressing inflammatory cytokines in LPS-stimulated macrophages. Silencing Ocilrp2 significantly promotes the binding of Syk to Dap12. Altogether, we identified the Ocilrp2 as a critical role in the TLR4 signaling pathway and inflammatory macrophages’ immune regulation, and added mechanistic insights into the crosstalk between TLR and Syk signaling.

Zebrafish sirt5 Negatively Regulates Antiviral Innate Immunity by Attenuating Phosphorylation and Ubiquitination of mavs

The signaling adaptor MAVS is a critical determinant in retinoic acid–inducible gene 1–like receptor signaling, and its activation is tightly controlled by multiple mechanisms in response to viral infection, including phosphorylation and ubiquitination. In this article, we demonstrate that zebrafish sirt5, one of the sirtuin family proteins, negatively regulates mavs-mediated antiviral innate immunity. Sirt5 is induced by spring viremia of carp virus (SVCV) infection and binds to mavs, resulting in attenuating phosphorylation and ubiquitination of mavs. Disruption of sirt5 in zebrafish promotes survival ratio after challenge with SVCV. Consistently, the antiviral responsive genes are enhanced, and the replication of SVCV is diminished in sirt5-dificient zebrafish. Therefore, we reveal a function of zebrafish sirt5 in the negative regulation of antiviral innate immunity by targeting mavs.

Reactive oxygen species-dependent-NLRP3 inflammasome activation in human neutrophils induced by l-amino acid oxidase derived from Calloselasma rhodostoma venom

l-Amino acid oxidase isolated from Calloselasma rhodostoma (Cr-LAAO) snake venom is a potent stimulus for neutrophil activation and production of inflammatory mediators, contributing to local inflammatory effects in victims of envenoming. Cr-LAAO triggered the activation of nicotinamide adenine dinucleotide phosphatase (NADPH) oxidase complex and protein kinase C (PKC)-α signaling protein for reactive oxygen species (ROS) production. This study aims to evaluate the ROS participation in the NLRP3 inflammasome complex activation in human neutrophil. Human neutrophils were isolated and stimulated for 1 or 2 h with RPMI (negative control), LPS (1 μg/mL, positive control) or Cr-LAAO (50 μg/mL). The neutrophil transcriptome was examined using the microarray technique, and RT-qPCR for confirmation of gene expression. Immunofluorescence assays for NLRP3, caspase-1, IL-1β and GSDMD proteins was performed by Western blot in the presence and/or absence of Apocynin, an inhibitor of NADPH oxidase. IL-1β release was also detected in the presence and/or absence of NLRP3, caspase-1 and NADPH oxidase inhibitors. Results showed that Cr-LAAO upregulated the expression of genes that participate in the NADPH oxidase complex formation and inflammasome assembly. NLRP3 was activated and accumulated in the cytosol forming punctas, indicating its activation. Gasdermin D was not cleaved but lactate dehydrogenase was released. Furthermore, ROS inhibition decreased the expression of NLRP3 inflammasome complex proteins, as observed by protein expression in the presence and/or absence of apocynin, an NADPH oxidase inhibitor. IL-1β was also released, and pharmacological inhibition of NLRP3, caspase-1, and ROS reduced the amount of released cytokine. This is the first report demonstrating the activation of the NLRP3 inflammasome complex via ROS generation by Cr-LAAO, which may lead to the development of local inflammatory effects observed in snakebite victims.