Immune Cell Responses Research Articles

Immune checkpoints are suppressed during pregnancy following influenza A virus infection.

Influenza A virus (IAV) infection is a major health risk during pregnancy. Whilst vaccination and antiviral agents are widely employed and reduce IAV-induced symptoms, they are not sufficient to control IAV infections in pregnancy, especially during pandemics. Respiratory viruses like IAV, exploit immune alterations that occur during pregnancy, including the upregulation of immune checkpoint proteins (ICPs) like PDL1, PD1 and CTLA4. We hypothesize that blocking expression of PDL1 on innate immune cells will improve maternal immunity following IAV infection. We utilized murine models of IAV infection during pregnancy with and without treatment with the immune checkpoint inhibitor (ICI), a-PDL1. Pregnant and non-pregnant mice were infected with mouse adapted IAV (A/PR/8) and assessed at 3 days post infection (3dpi). Lung cells were analyzed using flow cytometry. Lung mRNA expression of inflammatory and antiviral markers and histology was measured. Protein concentrations of inflammatory and antiviral markers, as well as viral titers was measured from lung bronchiolar lavage fluid (BALF). Lung function was also assessed. Following IAV infection, immune cells from pregnant mice had significant increases in the ICPs, PDL1, PD1 and CTLA4. a-PDL1 treatment effectively suppressed these ICPs and increased the activation marker, CD86. A-PDL1 treatment also reduced lung inflammatory cell infiltration and viral titres, increased antiviral responses, and improved lung function. Overall, IAV infection in pregnancy activates key inhibitory ICPs, leading to worsened disease outcomes. a-PDL1 treatment during IAV infection in pregnancy is an effective method to reduce ICP expression and improve overall immune cell responses.

FAM109B plays a tumorigenic role in low-grade gliomas and is associated with tumor-associated macrophages (TAMs)

BackgroundFamily with sequence similarity 109, member B (FAM109B) is involved in endocytic transport and affects genetic variation in brain methylation. It is one of the important genes related to immune cell-associated diseases. In the tumor immune system, methylation can regulate tumor immunity and influence the maturation and functional response of immune cells. Whether FAM109B is involved in tumor progression and its correlation with the tumor immune microenvironment has not yet been disclosed.MethodsA comprehensive pan-cancer analysis of FAM109B expression, prognosis, immunity, and TMB was conducted. The expression, clinical features, and prognostic value of FAM109B in low-grade gliomas (LGG) were evaluated using TCGA, CGGA, and Gravendeel databases. The expression of FAM109B was validated by qRT-PCR, immunohistochemistry (IHC), and Western blotting (WB). The relationship between FAM109B and methylation, Copy Number Variation (CNV), prognosis, immune checkpoints (ICs), and common chemotherapy drug sensitivity in LGG was explored through Cox regression, Kaplan–Meier curves, and Spearman correlation analysis. FAM109B levels and their distribution were studied using the TIMER database and single-cell analysis. The potential role of FAM109B in gliomas was further investigated through in vitro and in vivo experiments.ResultsFAM109B was significantly elevated in various tumor types and was associated with poor prognosis. Its expression was related to aggressive progression and poor prognosis in low-grade glioma patients, serving as an independent prognostic marker for LGG. Glioma grade was negatively correlated with FAM109B DNA promoter methylation. Immune infiltration and single-cell analysis showed significant expression of FAM109B in tumor-associated macrophages (TAMs). The expression of FAM109B was closely related to gene mutations, immune checkpoints (ICs), and chemotherapy drugs in LGG. In vitro studies showed increased FAM109B expression in LGG, closely related to cell proliferation. In vivo studies showed that mice in the sh-FAM109B group had slower tumor growth, slower weight loss, and longer survival times.ConclusionsFAM109B, as a novel prognostic biomarker for low-grade gliomas, exhibits specific overexpression in TAMs and may be a potential therapeutic target for LGG patients.

Beyond RNAi: How the Dicer protein modulates the antiviral innate immune response in mammalian cells: Mammalian Dicer could regulate the innate immune response in an RNAi-independent manner as a result of losing long dsRNA processive activity.

While Dicer plays an important antiviral role through the RNAi pathway in plants and invertebrates, its contribution to antiviral immunity in vertebrates and more specifically mammals is more controversial. The apparent limited RNAi activity in mammalian cells has been attributed to the reduced long dsRNA processive activity of mammalian Dicer, as well as a functional incompatibility between the RNAi and IFN pathways. Why Dicer has lost this antiviral activity in the profit of the IFN pathway is still unclear. We propose that the primary direct antiviral activity of Dicer has been functionally replaced by other sensors in the IFN pathway, leading to its specialization toward microRNA maturation. As a result, Dicer can regulate the innate immune response and prevent basal activation of the IFN pathway in mammals. Here, we discuss this hypothesis, highlighting how the adaptation of the helicase domain of mammalian Dicer may be key to this process.

Heat stress affects milk yield, milk quality, and gene expression profiles in mammary cells of Girolando cows

Heat stress during lactation affects the physiological responses, hormonal release, health, and productivity of dairy cows. However, the adverse effects of heat stress on milk synthesis, immune response, and cellular apoptosis in mammary cells remains unknown in Bos indicus cows. This study aimed to understand the relationship between milk yield, milk quality, and the expression of genes related to milk synthesis, cell apoptosis, and immune response in mammary cells of Girolando cows. Twenty-four Girolando cows (3/4 Holstein and 1/4 Gir) were subjected to control (CT, with a temperature-humidity index ranging from 60 to 74, n = 12) or heat stress treatments (HS, with a temperature- humidity index ranging from 60 to 85, n = 12), from 111 to 120 d of lactation. Heat stress significantly increased the expression of heat shock proteins (HSPD1 and HSPD90AA1), insulin receptors (INSR), and prolactin receptors (PRLRsf) genes, and decreased the expression of glucocorticoid receptor (NR3C1) gene in mammary cells of the HS cows when compared with the CT cows. The HS cows exhibited significantly higher vaginal temperatures and cortisol release compared with the CT cows. Moreover, the HS cows had significantly lower dry matter intake and milk yield than CT cows. Although, HS cows showed higher percentage of lymphocytes in milk when compared with that from CT cows. There was no effect of heat stress on other leukocyte counts, somatic cell counts, bacterial counts in milk, or milk composition. Finally, this study demonstrated that Girolando cows are susceptible to heat stress, which decreases milk yield and affects the expression of genes linked to milk synthesis in the mammary cells.

Dual-Modal Near-Infrared Organic Nanoparticles: Integrating Mild Hyperthermia Phototherapy with Fluorescence Imaging.

Our study seeks to develop dual-modal organic-nanoagents for cancer therapy and real-time fluorescence imaging, followed by their pre-clinical evaluation on a murine model. Integrating NIR molecular imaging with nanotechnology, our aim is to improve outcomes for early-stage cutaneous melanoma by offering more effective and less invasive methods. This approach has the potential to enhance both photothermal therapy (PTT) and Sentinel Lymph Node Biopsy (SLNB) procedures for melanoma patients. NIR-797-isothiocyanate was encapsulated in poly(D,L-lactide-co-glycolide) acid (PLGA) nanoparticles (NPs) using a two-step protocol, followed by thorough characterization, including assessing loading efficiency, fluorescence stability, and photothermal conversion. Biocompatibility and cellular uptake were tested in vitro on melanoma cells, while PTT assay, with real-time thermal monitoring, was performed in vivo on tumor-bearing mice under irradiation with an 808 nm laser. Finally, ex vivo fluorescence microscopy, histopathological assay, and TEM imaging were performed. Our PLGA NPs, with a diameter of 270 nm, negative charge, and 60% NIR-797 loading efficiency, demonstrated excellent stability and fluorescence properties, as well as efficient light-to-heat conversion. In vitro studies confirmed their biocompatibility and cellular internalization. In vivo experiments demonstrated their efficacy as photothermal agents, inducing mild hyperthermia with temperatures reaching up to 43.8 °C. Ex vivo microscopy of tumor tissue confirmed persistent NIR fluorescence and uniform distribution of the NPs. Histopathological and TEM assays revealed early apoptosis, immune cell response, ultrastructural damage, and intracellular material debris resulting from combined NP treatment and irradiation. Additionally, TEM analyses of irradiated zone margins showed attenuated cellular damage, highlighting the precision and effectiveness of our targeted treatment approach. Specifically tailored for dual-modal NIR functionality, our NPs offer a novel approach in cancer PTT and real-time fluorescence monitoring, signaling a promising avenue toward clinical translation.

In silico Identification of MHC Displayed Tumor Associated Peptides in Ovarian Cancer for Multi-Epitope Vaccine Construct.

Recognizing the potential of the immune system, immunotherapies have brought about a revolution in the treatment of cancer. Low tumour mutational burden and strong immunosuppression in the peritoneal tumor microenvironment (TME) lead to poor outcomes of immune checkpoint inhibition (ICI) and CART cell therapy in ovarian cancer. Alternative immunotherapeutic strategies are of utmost importance to achieve sound clinical success. The development of peptide vaccines based on tumor-associated antigens (TAAs) for ovarian cancer cells can be a potential target to provoke an anti-tumor immune response and subsequent clearance of tumour cells. The purpose of this in silico study was to find potential epitopes for a multi-epitope vaccine construct using the immunopeptidomics landscape of ovarian carcinoma. The four TAAs (MUC16, IDO1, FOLR1, and DDX5) were selected for potential epitopes prediction. The epitopes for B-cells, helper T-lymphocytes (HTL), and Cytotoxic Tlymphocytes (CTL) were predicted on the basis of antigenic, allergenic, and toxic properties. These epitopes were combined with suitable linkers and an adjuvant to form a multi-epitope construct. Four HTLs, 13 CTLs, and 6 potential B-cell epitopes were selected from the predicted epitope. The designed multi-epitope construct was potentially immunogenic, non-toxic, and non-allergenic. Physicochemical properties and higher-order structural analyses of the final construct revealed a potential vaccine candidate. The designed vaccine construct has the potential to trigger both humoral and cellular immune responses and may be employed as a therapeutic immunization candidate for ovarian malignancies. However, further in vitro and animal experimentation is required to establish the efficacy of the vaccine candidate.

TLR10 (CD290) Is a Regulator of Immune Responses in Human Plasmacytoid Dendritic Cells.

TLRs are the most thoroughly studied group of pattern-recognition receptors that play a central role in innate immunity. Among them, TLR10 (CD290) remains the only TLR family member without a known ligand and clearly defined functions. One major impediment to studying TLR10 is its absence in mice. A recent study on TLR10 knock-in mice demonstrated its intrinsic inhibitory role in B cells, indicating that TLR10 is a potential drug target in autoimmune diseases. In this study, we interrogated the expression and function of TLR10 in human plasmacytoid dendritic cells (pDCs). We have seen that primary human pDCs, B cells, and monocytes constitutively express TLR10. Upon preincubation with an anti-TLR10 Ab, production of cytokines in pDCs was downregulated in response to stimulation with DNA and RNA viruses. Upon further investigation into the possible mechanism, we documented phosphorylation of STAT3 upon Ab-mediated engagement of TLR10. This leads to the induction of inhibitory molecule suppressor of cytokine signaling 3 (SOCS3) expression. We have also documented the inhibition of nuclear translocation of transcription factor IFN regulatory factor 7 (IRF7) in pDCs following TLR10 engagement. Our data provide the (to our knowledge) first evidence that TLR10 is constitutively expressed on the surface of human pDCs and works as a regulator of their innate response. Our findings indicate the potential of harnessing the function of pDCs by Ab-mediated targeting of TLR10 that may open a new therapeutic avenue for autoimmune disorders.

Pseudonormal Morphology of Salivary Gland Adenoid Cystic Carcinoma Cells Subverts the Antitumor Reactivity of Immune Cells: A Tumour-Cell-Based Initiation of Immune Evasion.

Salivary gland adenoid cystic carcinoma (ACC), mucoepidermoid carcinoma (MEC) and oral squamous cell carcinoma (OSCC) occurs within the head and neck region. So far immune check point inhibitors failed in ACC. Gipie (CCDC88B) is a microtubule linker protein that activates immune cells. Gipie expressions found in head and neck cancer cells. We hypothesised that the presence of Gipie diminishes anti-tumour reactivity of immune cells towards head and neck cancer. To determine the effect of Gipie in oral and salivary gland cancer cells, Gipie was silenced in cancer cells in cancer-immune cells co-culture models and we performed 3D Z series confocal imaging, annexin V and immune activation flow cytometry, proteome profiler and discovery phase proteomics. ACC cells morphed into pseudonormal morphology in immune co-culture models. Silencing Gipie in ACC cells showed significant increase of apoptotic cells and activated natural killer cells, and lowering of regulatory T cells. Other salivary and oral cancer cells showed negligible effect of Gipie. Proteome profiler and proteomics assay confirmed Gipie affecting proliferation mechanism and immune activated proteins in ACC immune co-culture models. Overall, we conclude that the presence of Gipie has a confounding role during the ACC-immune cell interaction.

P.029: Immunological insight into IgA nephropathy: Dissecting immune cell responses and transcriptomic profiles for targeted therapeutic strategies.

P.029: Immunological insight into IgA nephropathy: Dissecting immune cell responses and transcriptomic profiles for targeted therapeutic strategies.

Western Diet-Induced Nonalcoholic Fatty Liver Disease Mice Mimic the Key Transcriptomic Signatures Observed in Humans

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease characterized by the accumulation of fat in the liver in the absence of excessive alcohol consumption or a secondary cause of hepatic steatosis. The prevalence of NAFLD is increasing worldwide and its management has become a public health concern. Animal models are traditionally used to elucidate disease mechanisms and identify potential drug targets; however, their translational aspects in human diseases have not been fully established. This study aimed to clarify the utility of animal models for translational research by assessing their relevance to human diseases using gene expression analysis. Weighted gene co-expression network analysis of liver tissues from Western diet (WD)-induced NAFLD mice was performed to identify the modules associated with disease progression. Moreover, the similarity of the gene co-expression network across species was evaluated using module preservation analysis. Nineteen disease-associated modules were identified. The brown module was positively associated with disease severity, and functional analyses indicated that it may be involved in inflammatory responses in immune cells. Moreover, the gene co-expression network of the brown module was highly preserved in human NAFLD liver gene expression datasets. These results indicate that WD-induced NAFLD mice have similar gene co-expression networks (especially genes associated with inflammatory responses) to humans and are thought to be a useful experimental tool for preclinical research on NAFLD.

An alveolus lung-on-a-chip model of Mycobacterium fortuitum lung infection.

Lung disease due to non-tuberculous mycobacteria (NTM) is rising in incidence. While both two dimensional cell culture and animal models exist for NTM infections, a major knowledge gap is the early responses of human alveolar and innate immune cells to NTM within the human alveolar microenvironment. Here we describe development of a humanized, three-dimensional, alveolus lung-on-a-chip (ALoC) model of Mycobacterium fortuitum lung infection that incorporates only primary human cells such as pulmonary vascular endothelial cells in a vascular channel, and type I and II alveolar cells and monocyte-derived macrophages in an alveolar channel along an air-liquid interface. M. fortuitum introduced into the alveolar channel primarily infected macrophages, with rare bacteria inside alveolar cells. Bulk-RNA sequencing of infected chips revealed marked upregulation of transcripts for cytokines, chemokines and secreted protease inhibitors (SERPINs). Our results demonstrate how a humanized ALoC system can identify critical early immune and epithelial responses to M. fortuitum infection. We envision potential application of the ALoC to other NTM and for studies of new antibiotics.

Indirubin induces tolerogenic dendritic cells via aryl hydrocarbon receptor activation and ameliorates allergic asthma in a murine model by expanding Foxp3-expressing regulatory T cells

BackgroundAllergic asthma is a chronic bronchial inflammatory disease closely associated with abnormal immune responses of dendritic cells (DCs) and allergen-specific type 2 T helper (Th2) cells. Indirubin (IR), a natural aryl hydrocarbon receptor (AhR) ligand, exerts anti-inflammatory and immunomodulatory properties. PurposeIn this study, we aimed to clarify whether IR exhibits immunomodulatory action on DCs via AhR activation and investigated the antiallergic effects of IR in a mouse model of allergic asthma. MethodsLipopolysaccharide (LPS)-activated bone marrow-derived DCs were treated with IR. Their mRNA expressions, cytokine production, and phenotype patterns were determined by a quantitative real-time PCR, ELISA, flow cytometry, and RNA sequencing. The mixed lymphocyte reaction was utilized to evaluate the regulatory function of IR-treated DCs on T-cell differentiation. Moreover, mice with ovalbumin (OVA)-induced allergic asthma were treated with IR. Thereafter, the airway hyperresponsiveness (AHR), allergen-specific IgE production, cytokine levels, airway inflammation, and T-cell responses were evaluated. ResultsTreatment of LPS-stimulated DCs with 20 μM IR significantly reduced IL-12 and TNF-α production while increasing IL-10 secretion. Meanwhile, these DCs expressed decreased levels of CD80 but increased levels of Jagged 1 surface molecules. However, the effects of IR on DCs were reversed by pretreatment with the AhR antagonist, CH223191. Additionally, the coculture of these tolerogenic-like DCs with allogeneic CD4+T cells promoted the generation of Foxp3+ regulatory T (Treg) cells. A transcriptomic analysis identified several downregulated genes that are involved in regulating cell migration, cytokine secretion, and inflammatory responses in DCs after IR treatment. In an asthmatic murine model, oral administration of 25 mg kg-1 body weight of IR efficiently alleviated the development of AHR, OVA-specific IgE production, and levels of Th2-type cytokines (IL-4, IL-5, and IL-13) and the CCL11 chemokine. IR treatment also attenuated inflammatory cell recruitment and mucus production in the lungs. Notably, an enhanced frequency of Foxp3+ Treg cells and reduced effector T-cell proliferation associated with increased levels of IL-10 and TGF-β were observed in IR-treated mice. ConclusionIR can induce tolerogenic-like BMDCs which promote the differentiation of Treg cells. Importantly, the expansion of Foxp3+ Treg cells contributed to the therapeutic efficacy of IR against allergic asthma.

Targeting CD36-Mediated Lipid Metabolism by Selective Inhibitor-Augmented Antitumor Immune Responses in Oral Cancer.

The fatty acid receptor CD36 is expressed on various malignant cells and is suggested to contribute to tumor progression. CD36 is also expressed by several immune cells and involved in immune responses and may be a potential target in cancer immunotherapy. In this study, we investigated whether the selective inhibition of CD36 can inhibit tumor progression and facilitate an antitumor immune response in oral squamous carcinoma cells (OSCCs). We assessed the effects of sulfosuccinimidyl oleate sodium (SSO), a CD36 inhibitor, on the proliferation apoptosis and alteration in tumor cell surface expression levels of immune accessory molecules in vitro. We also assessed whether SSO-treated OSCCs could promote a T cell response via a Mixed Lymphocyte Reaction (MLR) assay. We also investigated the direct antitumor effects and immunomodulatory effects of SSO using a mouse oral cancer OSCC model. SSO treatment significantly inhibited OSCC proliferation, increased apoptotic cell death, and upregulated the cell surface expression of several immune accessory molecules, including CD83, MHC-Class II, and PD-L1. SSO-treated OSCCs augmented T cell proliferation following MLR. In vivo SSO administration significantly attenuated mouse tumor growth with an increased proportion of immune cells, including CD4+ T, CD8+ T, and dendritic cells; it also decreased the proportion of immune suppressive cells, such as myeloid-derived suppressor and regulatory T cells. These results suggest that the selective inhibition of CD36 can induce direct and indirect antitumor effects by facilitating host antitumor immune responses in OSCCs.

A manganese-doped layered double hydroxide loaded with lactate oxidase and DNA repair inhibitors for synergistically enhanced tumor immunotherapy

Tumor immunotherapy has gained more and more attention in tumor treatment. However, the accumulation of lactic acid in tumor tissue inhibits the response of immune cells to form an immunosuppressive microenvironment (ISME). To reverse the ISME, an acid-responsive nanoplatform (termed as MLLN@HA) is reported for synergistically enhanced tumor immunotherapy. MLLN@HA is constructed by the co-loading of lactate oxidase (LOX) and DNA repair inhibitor (NU7441) in a manganese-doped layered double hydroxide (Mn-LDH), and then modified with hyaluronic acid (HA) for tumor-targeted delivery. After endocytosis by tumor cells, MLLN@HA decomposes and releases LOX, NU7441 and Mn2+ ions in the acidic tumor microenvironment. The released LOX catalyzes the conversion of lactic acid into hydrogen peroxide (H2O2), which not only alleviates the ISME, but also provides reactants for the Mn2+-mediated Fenton-like reaction to enhance chemodynamic therapy (CDT). Released NU7441 prevents CDT-induced DNA damage from being repaired, thereby increasing double-stranded DNA (dsDNA) fragments within tumor cells. Importantly, the released Mn2+ ions enhance the sensitivity of cyclic GMP-AMP synthase (cGAS) to dsDNA fragments, and activate the stimulator of interferon genes (STING) to induce an anti-tumor immune response. Such an orchestrated immune-boosting strategy ultimately achieves effective tumor growth inhibition and prevents tumor lung metastasis. Statement of significanceTo improve the efficacy of tumor immunotherapy, an innovative acid-responsive MLLN@HA nanoplatform was developed for synergistically enhanced tumor immunotherapy. The MLLN@HA actively targets to tumor cells through the interaction of HA with CD44, and then degrades to release LOX, NU7441 and Mn2+ ions in the acidic tumor microenvironment. The released LOX generates H2O2 for the Mn2+-mediated Fenton reaction and reverses the ISME by consuming lactate. NU7441 prevents DNA damage repair, leading to an increased concentration of free DNA fragments, while Mn2+ ions activate the cGAS-STING pathway, enhancing the systemic anti-tumor immune response. The orchestrated immune-boosting nanoplatform effectively inhibits tumor growth and lung metastasis, presenting a promising strategy for cancer treatment.

Transcriptomic analysis reveals bovine herpesvirus 1 infection regulates innate immune response resulted in restricted viral replication in neuronal cells

BackgroundBovine herpesvirus 1 (BoHV-1) is a major pathogen that affects the global bovine population, primarily inducing respiratory and reproductive disorders. Its ability to establish latent infections in neuronal cells and to reactivate under certain conditions poses a continual threat to uninfected hosts. In this study, we aimed to analyze the replication characteristics of BoHV-1 in neuronal cells, as well as the effects of viral replication on host cell immunity and physiology. MethodsUsing the Neuro-2a neuronal-origin cell line as a model, we explored the dynamics of BoHV-1 replication and analyzed differential gene expression profiles post-BoHV-1 infection using high-throughput RNA sequencing. ResultsBoHV-1 demonstrated restricted replication in Neuro-2a cells. BoHV-1 induced apoptotic pathways and enhanced the transcription of interferon-stimulated genes and interferon regulatory factors while suppressing the complement cascade in Neuro-2a cells. ConclusionsDifferent from BoHV-1 infection in other non-highly differentiated somatic cells result in viral dominance, BoHV-1 regulated the innate immune response in neuronal cells formed a “virus-nerve cell” relative equilibrium state, which may account for the restricted replication of BoHV-1 in neuronal cells, leading to a latent infection. These findings provide a foundation for further research into the mechanism underlying BoHV-1-induced latent infection in nerve cells.

Lymph node-targeted STING agonist nanovaccine against chronic HBV infection

Chronic hepatitis B virus (HBV) infection is a global health problem that substantially increases the risk of developing liver disease. The development of a novel strategy to induce anti-HB seroconversion and achieve a long-lasting immune response against chronic HBV infection remains challenging. Here, we found that chronic HBV infection affected the signaling pathway involved in STING-mediated induction of host immune responses in dendritic cells (DCs) and then generated a lymph node-targeted nanovaccine that co-delivered hepatitis B surface antigen (HBsAg) and cyclic diguanylate monophosphate (c-di-GMP) (named the PP-SG nanovaccine). The feasibility and efficiency of the PP-SG nanovaccine for CHB treatment were evaluated in HBV-carrier mice. Serum samples were analyzed for HBsAg, anti-HBs, HBV DNA, and alanine aminotransferase levels, and liver samples were evaluated for HBV DNA and RNA and HBcAg, accompanied by an analysis of HBV-specific cellular and humoral immune responses during PP-SG nanovaccine treatment. The PP-SG nanovaccine increased antigen phagocytosis and DC maturation, efficiently and safely eliminated HBV, achieved a long-lasting immune response against HBV reinjection, and disrupted chronic HBV infection-induced immune tolerance, as characterized by the generation and multifunctionality of HBV-specific CD8+ T and CD4+ T cells and the downregulation of immune checkpoint molecules. HBV-carrier mice immunized with the PP-SG nanovaccine achieved partial anti-HBs seroconversion. The PP-SG nanovaccine can induce sufficient and persistent viral suppression and achieve anti-HBs seroconversion, rendering it a promising vaccine candidate for clinical chronic hepatitis B therapy.

A Guideline Strategy for Identifying a Viral Gene/Protein Evading Antiviral Innate Immunity.

Antiviral innate immunity is the first line of defence against viruses. The interferon (IFN) signaling pathway, the DNA damage response (DDR), apoptosis, endoplasmic reticulum (ER) stress, and autophagy are involved in antiviral innate immunity. Viruses abrogate the antiviral immune response of cells to replication in various ways. Viral genes/proteins play a key role in evading antiviral innate immunity. Here, we will discuss the interference of viruses with antiviral innate immunity and the strategy for identifying viral gene/protein immune evasion.

L-Theanine Alleviates Ulcerative Colitis by Regulating Colon Immunity via the Gut Microbiota in an MHC-II-Dependent Manner.

Alterations to the gut microbiota are associated with ulcerative colitis (UC), whereas restoration of normobiosis can effectively alleviate UC. l-Theanine has been shown to reshape the gut microbiota and regulate gut immunity. To investigate the mechanisms by which l-theanine alleviates UC, we used l-theanine and l-theanine fecal microbiota solution to treat UC mice. In this study, we used l-theanine and l-theanine fecal microbiota solution to treat UC mice to explore the mechanism by which l-theanine alleviates UC. By reducing inflammation in the colon, we demonstrated that l-theanine alleviates symptoms of UC. Meanwhile, l-theanine can improve the abundance of microbiota related to short-chain fatty acid, bile acid, and tryptophan production. Single-cell sequencing results indicated that l-theanine-mediated suppression of UC was associated with immune cell changes, especially regarding macrophages and T and B cells, and validated the immune cell responses to the gut microbiota. Further, flow cytometry results showed that the ability of dendritic cells, macrophages, and monocytes to present microbiota antigens to colonic T cells in an MHC-II-dependent manner was reduced after treating normal mouse fecal donors with l-theanine. These results demonstrate that l-theanine modulates colon adaptive and innate immunity by regulating the gut microbiota in an MHC-II-dependent manner, thereby alleviating UC.

Activation of α7 nicotinic acetylcholine receptors inhibits hepatic necroptosis and ameliorates acute liver injury in mice.

Acute liver injury (ALI) is a disease characterized by severe liver dysfunction, caused by significant infiltration of immune cells and extensive cell death with a high mortality. Previous studies demonstrated that the α7 nicotinic acetylcholine receptor (α7nAChR) played a crucial role in various liver diseases. The hypothesis of this study was that activating α7nAChR could alleviate ALI and investigate its possible mechanisms. ALI was induced by intraperitoneal injection of lipopolysaccharide (LPS)/D-galactosamine (D-Gal) in wild type (WT), α7nAChR knockout (α7nAChR -/-) and Sting mutation (Stinggt/gt) mice in the presence or absence of a pharmacological selective α7nAChR agonist (PNU-282987). The effects of α7nAChR on hepatic injury, inflammatory response, mitochondrial damage, necroptosis and infiltration of immune cells during ALI were assessed. The expression of α7nAChR in liver tissue was increased in LPS/D-Gal induced ALI mice. Compared to the age-matched WT mice, α7nAChR deficiency decreased the survival rate, exacerbated the hepatic injury accompanied with enhanced inflammatory response and oxidative stress, and aggravated hepatic mitochondrial damage and necroptosis. Conversely, pharmacological activation of α7nAChR by PNU-282987 displayed the opposite trends. Furthermore, PNU-282987 significantly reduced the proportion of infiltrating monocyte-derived macrophages (CD45+CD11bhiF4/80int), M1 macrophages (CD45+CD11b+F4/80+CD86 hiCD163low), Ly6Chi monocytes (CD45+CD11b+MHCⅡ lowLy6C hi), but increased the resident Kupffer cells (CD45+CD11bintF4/80 hiTIM4 hi) in the damaged hepatic tissues caused by LPS/D-Gal. Interestingly, α7nAChR deficiency promoted the STING signaling pathway under LPS/D-Gal stimulation, while PNU-282987 treatment significantly prevented its activation. Finally, it was found that Sting mutation abolished the protective effects against hepatic injury by activating α7nAChR. Our study revealed that activating α7nAChR could protect against LPS/D-Gal induced ALI by inhibiting hepatic inflammation and necroptosis possibly via regulating immune cells infiltration and inhibiting STING signaling pathway.

Xenogenous implanted dental follicle stem cells promote periodontal regeneration through inducing the N2 phenotype of neutrophils

BackgroundPeriodontal tissue loss is the main reason for tooth mobility and loss caused by periodontal disease. Dental follicle stem cells (DFSCs) have significant therapeutic potential in periodontal regeneration, which maybe mainly depends on their potent immunomodulatory capacity. Consequently, this study aims to elucidate the impact of implanted xenogenous DFSCs on innate immune responses during early and late stages in the periodontal defect repair period.MethodsTo trace and investigate the immunomodulation mechanisms of DFSCs in vivo, DFSCs were engineered (E-DFSCs) using lentiviral vectors expressing CD63-enhanced green fluorescent protein (CD63-EGFP) and β-Actin-mCherry protein (ACTB-mCherry) to exhibit green and red fluorescence. The biological characteristics and functions of E-DFSCs were verified by proliferation, differentiation, and co-culture experiments in vitro. In vivo, the periodontal regeneration capacity of E-DFSCs was detected by implantation of murine periodontal defect model, and the response of innate immune cells was detected at the 1st, 3rd, and 5th days (early stage) and 4th week (late stage) after implantation.ResultsIn vitro assessments showed that E-DFSCs retain similar properties to their non-engineered counterparts but exhibit enhanced macrophage immunomodulation capability. In mice models, four-week micro-CT and histological evaluations indicated that E-DFSCs have equivalent efficiency to DFSCs in periodontal defect regeneration. At the early stage of repair in mice periodontal defect, fluorescence tracking showed that implanted E-DFSCs might primarily activate endogenous cells through direct contact and indirect actions, and most of these cells are myeloperoxidase-positive neutrophils. Additionally, compared with the control group, the neutrophilic infiltration and conversion of N2-type were significantly increased in the E-DFSC group. At the late stage of defect regeneration, more M2-type macrophages, fewer TRAP + osteoclasts, and an upregulated OPG/RANKL ratio were detected in the E-DFSC group compared to the control group, which indicated that immune balance tilts towards healing and bone formation.ConclusionThe xenogenous implanted DFSCs can induce the N2 phenotype of neutrophils in the early stage, which can activate the innate immune mechanism of the host to promote periodontal tissue regeneration.