Search Results (1,591)

Polybrominated diphenyl ethers (PBDEs), widely used as brominated flame retardants, are known to exert persistent adverse effects on the immune systems of humans and other organisms. Previous studies have demonstrated that 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47), a prevalent congener, induces apoptosis, impairs phagocytic function, and triggers aberrant immune-inflammatory reactions in RAW264.7 macrophages via the induction of elevated intracellular reactive oxygen species (ROS). However, the underlying regulatory mechanism remains unclear. The nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) signaling pathway is a key cellular defense system against oxidative stress. In this study, we investigated the role of the Nrf2/ARE pathway in BDE-47-induced macrophage immunotoxicity. Network toxicology analysis identified Nrf2 as a hub gene within the BDE-47-associated immunotoxicity network. Molecular docking and molecular dynamics simulations suggested a potential interaction between BDE-47 and the Keap1-Nrf2 complex, with moderate binding affinity. Experimental studies in RAW264.7 cells showed that BDE-47 exposure activated the Nrf2/ARE pathway, as evidenced by Nrf2 nuclear translocation and the differential upregulation of downstream genes (GCLC, GCLM, HO-1, NQO1, SOD1, and CAT). Importantly, Nrf2 knockdown via lentiviral shRNA or pharmacological inhibition with brusatol significantly exacerbated BDE-47-induced apoptosis and immune dysfunction, including enhanced pro-inflammatory cytokine production and impaired phagocytosis. These results demonstrate that Nrf2/ARE pathway activation represents an adaptive antioxidant response and contributes to limiting BDE-47-induced cytotoxicity and immune impairment in macrophages. Full article

Class B scavenger receptor BI splice variants (SR-BI) and BII (SR-BII) internalize lipoproteins but also bind and internalize bacteria. Their individual roles in sepsis are unknown. We overexpressed human SR-BI or BII in transgenic mice, primarily in the liver, but also in the kidney and in bone marrow-derived macrophages, and then performed cecal ligation and puncture (CLP) surgery. SR-BI and BII transgenic mice had significantly worse survival compared to WT mice. Twenty-four hours after CLP, liver injury markers and histological damage were elevated in both SR-BI and BII transgenic mice, whereas kidney damage was similar. Systemic inflammatory cytokines were markedly increased in SR-BI and BII transgenic mice; parallel increases were seen in liver mRNA expression, but not in the kidney. The highest degree of neutrophil infiltration was observed in the liver of SR-BI. Human SR-BI and BII dramatically decreased bacterial accumulation in the liver. Green fluorescent protein-labeled E. coli were efficiently phagocytosed in hepatic macrophages of SR-BI and BII transgenic mice; phagocytosis was more prominent in SR-BII transgenic mice. Finally, human SR-BI overexpression reduced systemic HDL-C levels, eliminated adrenal cortex lipid droplets, and dampened the systemic increase of corticosterone after CLP. Supplementation with glucocorticoid and mineralocorticoid improved survival in SR-BI but not in SR-BII transgenic mice after CLP. In summary, our findings suggest human SR-BI and BII overexpression contributes to higher mortality after CLP by different mechanisms: excessive inflammatory response due to adrenal insufficiency (SR-BI) or hyperactive phagocytosis (SR-BII) in the liver. Full article

The retromer is a highly conserved complex that mediates the trafficking of cargo proteins to the plasma membrane or the trans-Golgi network. In pathogenic microorganisms, retromer-dependent transport contributes to the delivery of virulence factors and promotes infection. The retromer consists of a sorting nexin dimer (SNX) and a cargo-selection complex (CSC), formed by Vps26, Vps35, and Vps29. In Entamoeba histolytica, the parasite that causes human amoebiasis, the retromer functions as a Rab7A GTPase effector and participates in phagocytosis and cytotoxicity. Although we previously characterized the roles of EhVps26 and EhVps35, the function of EhVps29 remained unclear. In this study, we analyzed the subcellular localization and functional role of EhVps29 in adhesion, phagocytosis, and cytopathic effect. EhVps29 localized to the plasma membrane, cytosol, vesicles, tubules, Golgi-like structures, MVBs and, for the first time, the nucleus. Immunofluorescence and Western blot assays demonstrated that EhVps29 modulates the localization of EhVps26, EhADH adhesin, and EhCP112 cysteine protease. Ehvps29 gene silencing and overexpression confirmed its involvement in virulence-associated processes. Immunoprecipitation and confocal microscopy results showed the interaction among EhVps29 and the ESCRT machinery members EhVps36 and EhADH. Our results indicate that EhVps29 is involved in parasite virulence and protein trafficking through recycling or degradation pathways. Full article

Prominin-1 (Prom1/CD133) has long been recognized as a structural determinant of photoreceptor outer segment (OS) morphogenesis, yet rapidly accumulating evidence extends its role to retinal pigment epithelium (RPE) homeostasis, encompassing autophagy–lysosomal flux, outer segment phagocytosis, mitochondrial function, and regulation of inflammatory stress. This review synthesizes mechanistic and transcriptomic insights that position PROM1 as a central regulator of photoreceptor and RPE integrity, reframing Prom1 disease as a multi-compartment retinal disorder relevant to both inherited retinal dystrophies (IRDs) and atrophic age-related macular degeneration (aAMD). We develop a dual-axis conceptual model in which Prom1 dysfunction can initiate pathology in either the photoreceptors (OS morphogenesis failure) or the RPE, including impaired autophagic flux, lysosomal activity, defective phagocytosis, and Epithelial-Mesenchymal Transition (EMT)-like de-differentiation, with secondary cross-compartmental degeneration. Clinically, autosomal-dominant missense variants associate with macular or cone-rod dystrophy, whereas biallelic truncating/splice-site mutations drive early-onset rod–cone disease and panretinal/RPE atrophy, illustrating genotype–phenotype diversity. By integrating recent high-resolution transcriptomic data from Prom1-deficient RPE cells with long-standing insights into photoreceptor biology, we highlight converging pathways of degeneration that challenge a photoreceptor-centric view and unify disparate phenotypes within a single molecular framework. These insights broaden the therapeutic landscape, advancing gene augmentation and pathway-targeted strategies to preserve RPE integrity, sustain photoreceptor function, and modify disease course in PROM1-associated IRDs and atrophic AMD. Full article

A polysaccharide from Rhodomyrtus tomentosa (Aiton) Hassk. fruit (RTFP-2b) was isolated and purified. RTFP-2b has a molecular weight of 22.995 kDa and consists of nine monosaccharides, with arabinose (38.68%), galactose (21.86%), and galacturonic acid (14.83%) as its major components. Methylation and NMR analyses revealed dominant glycosidic linkages, including α-L-Araf-(1→, →4)-α-D-GalpA-(1→, →4)-α-D-Galp-(1→, →5)-α-L-Araf-(1→, →3)-α-L-Araf-(1→, →2)-α-L-Rhap-(1→, and →3,4,6)-β-D-Galp-(1→. Bioactivity assays using lipopolysaccharide (LPS)-stimulated RAW264.7 cells showed that RTFP-2b exhibits dose-dependent immunomodulatory properties. When administered at lower concentrations (100–200 μg/mL), RTFP-2b enhanced phagocytosis and IL-1β production. At higher concentrations (300–400 μg/mL), it significantly suppressed nitric oxide and showed biphasic regulation of IL-1β, but unexpectedly increased IL-6 levels in LPS-stimulated RAW264.7 cells. These immunomodulatory effects of RTFP-2b at higher doses were accompanied by inhibition of NF-κB signaling. These findings indicate that RTFP-2b is a structurally distinct acidic polysaccharide with dose-dependent immunomodulatory properties, suggesting its potential application in functional foods or pharmaceuticals. Full article

The purpose of this project was to define gene expression changes associated with the acquisition and loss of resilience to diabetic retinopathy (RDR) in individual retinal cell types. A non-immune form of type 1 diabetes mellitus (DM) was induced by injecting male C57Bl6J mice with streptozotocin. Single-cell RNA sequencing was performed on retinas from mice that experienced DM for 5 or 15 days, along with retinas from age-matched, non-DM mice. The resulting data sets were analyzed to identify DM-associated differentially expressed genes and pathway enrichments after each duration of DM. We observed that acquisition of RDR, previously shown to arise after 5 days of DM was linked to altered expression of genes in a subset of retinal cells, mainly Müller cells. Pathway analysis indicated enhancement of numerous modes of protection, including reinforced neurovascular and structural homeostasis through phagocytosis, integrin signaling, and interferon-mediated defense. After 15 days of DM, when we previously showed that RDR is waning this pro-protection surge in gene expression subsided. We conclude that a duration of DM that is too short to cause diabetic retinopathy (DR) nonetheless evoked a profound change in the gene expression profile within a subset of retinal cell types. The nature and timing of this molecular shift indicated that it was not the preamble to DM-related damage that eventually develops. Rather, DM engaged numerous defense programs within Müller cells. The temporal alignment between RDR and activation of Müller cell-based defense provides a molecular foundation for the retina’s transient ability to remain healthy in the face of DM. Full article

The single von Willebrand factor C (SVWC) domain-containing protein family represents a crucial class of immune molecules recently identified in insects and crustaceans. Initially regarded as functional analogs of vertebrate interferons (IFNs) due to their virus-induced expression and activation of the Janus kinase-signal transducer and activator of the transcription (JAK-STAT) pathway, recent studies have revealed that SVWC proteins possess far more complex functions. Many SVWC members are themselves a novel class of pattern recognition receptors (PRRs) that can directly bind to viruses and bacteria. Importantly, SVWCs are not a single entity but a highly diverse family—multiple subtypes exist in Drosophila, Bombyx mori, and shrimp—a gene expansion that implies functional differentiation. This review systematically examines the multifunctionality of SVWC proteins in insects and crustaceans, with a particular focus on the functional specialization driven by subtype diversity. We delve into the complex regulatory networks governing SVWC expression, including the differential activation by nuclear factor kappa B (NF-κB) pathways (Dorsal, Rel-2, Relish) and interferon regulatory factor (IRF) pathways. We detail the unique signaling mechanism by which SVWCs activate the JAK-STAT pathway via integrins, rather than the canonical Domeless receptor. Furthermore, we extend the discussion to the emerging roles of SVWCs as PRRs in humoral immunity (activating Toll/IMD pathways to induce antimicrobial peptides) and cellular immunity (mediating hemocyte phagocytosis). Based on current evidence, We propose that diverse SVWC subtypes may recognize distinct pathogens, bind to different integrin receptors, and activate specific STAT variants via disparate upstream induction pathways, thereby establishing a systematic and hierarchical immunoregulatory network. This understanding positions the SVWC protein family as a central hub in the insect immune network and offers a novel perspective on the complexity and evolution of invertebrate immunity. Full article

Liver diseases, ranging from chronic hepatitis and metabolic dysfunction to cirrhosis and hepatocellular carcinoma, represent a major global public health burden. As an immune-privileged organ, the liver harbors a unique and intricate immune microenvironment, which plays a dual role in pathogen clearance and chronicity. Kupffer cells (KCs), the primary resident macrophages in the liver, constitute the first line of defense in liver innate immunity and play complex and important roles in pathogen recognition, phagocytosis, and the regulation of liver inflammation and immune responses. The complement receptor of the immunoglobulin superfamily (CRIg) is a membrane receptor that is specifically expressed on KCs. It serves not only as a sentinel for the liver against pathogen invasion but also as a sophisticated regulator for maintaining immune homeostasis. As a key component of the liver’s immune system, CRIg can efficiently mediate the clearance of complement-opsonized particles, thereby playing multidimensional roles in pathogen clearance, antigen cross-presentation, and the establishment of immune tolerance, functioning as both a “pathogen catcher” and an “immune brake.” This review focuses on the CRIg molecule, detailing its mechanisms in the recognition and phagocytic clearance by KCs, and its subsequent impact on hepatic immune responses. Furthermore, we explored the potential involvement of CRIg in the pathological progression of diverse liver diseases, including persistent inflammation, fibrosis, and hepatocarcinogenesis. This synthesis provides novel insights into the immunopathology of liver diseases and establishes a theoretical foundation for developing CRIg-targeted therapeutic strategies. Full article

Pseudomonas plecoglossicida causes bacterial hemorrhagic ascites in ayu (Plecoglossus altivelis), a lethal disease characterized by abdominal distension with hemorrhagic ascites, multifocal organ hemorrhages, and histopathologically evident hepatocellular necrosis and inflammatory infiltration. The lack of effective treatments exacerbates mass mortalities, posing a significant threat to aquaculture. Given the severe pathogenesis of P. plecoglossicida infection—which involves bacterial colonization, tissue necrosis, and host immune dysregulation—effective therapeutic strategies are urgently needed. Through a screen of traditional Chinese medicine monomers, we identified harmine, an indole alkaloid derived from Peganum harmala seeds, as a potent agent against this pathogen. In vivo, harmine exhibited direct bactericidal activity by disrupting membrane integrity, as evidenced by increasing membrane permeability, and inhibiting biofilm formation. In an ayu infection model, harmine significantly increased host survival, reduced tissue bacterial load, and enhanced innate immunity by augmenting monocyte/macrophage phagocytosis and bactericidal capacity while suppressing pro-inflammatory cytokine release and apoptosis. Mechanistically, the Drug Affinity Responsive Target Stability assay was used to identify the molecular target of harmine, followed by functional validation through PRDX6−knockdown experiments. Harmine exhibited direct bactericidal activity by disrupting membrane integrity and inhibiting biofilm formation. In the ayu infection model, harmine significantly increased host survival, reduced tissue bacteria1 load, and enhanced innate immunity by augmenting monocyte/macrophage system and bactericidal capacity while suppressing pro-inflammatory cytokine release and apoptosis, the latter likely through modulation of PRDX6−mediated oxidative stress and downstream caspase signaling. Mechanistically, DARTS revealed that harmine binds to peroxiredoxin 6 (PRDX6), a multifunctional enzyme possessing peroxidase, phospholipase A₂, and lysophosphatidylcholine acyltransferase activities. This binding liberates TNF receptor-associated factor 6 (TRAF6), facilitating its mitochondrial translocation and association with the ECSIT signaling integrator complex, thereby amplifying mitochondrial reactive oxygen species (mROS) production and potentiating macrophage-mediated bacterial killing. These findings establish harmine as a promising therapeutic candidate for controlling P. plecoglossicida infections and underscore the value of host-directed immunomodulation derived from natural products in aquaculture medicine. Full article

Intracerebral hemorrhage induces severe secondary brain injury characterized by excessive neuroinflammation and inefficient hematoma clearance, processes largely governed by microglial polarization and phagocytic activity. The immunoproteasome, an inducible proteasome isoform involved in immune regulation, has been implicated in inflammatory neurological disorders, but its role in microglial responses after ICH remains unclear. In this study, rat models of common hemorrhage, severe hemorrhage, and severe hemorrhage with hematoma aspiration were used to represent graded injury severity and post-evacuation recovery. Transcriptomic profiling at day 3 post-injury identified immunoproteasome-associated gene networks, while expression of the catalytic subunits LMP2 and LMP7, microglial polarization markers, and phagocytic receptors was analyzed by Western blotting and immunofluorescence. Severe hemorrhage markedly induced LMP2 and LMP7 expression, predominantly in Iba1⁺ microglia, accompanied by enhanced ER stress, NF-κB signaling, and M1-like polarization and reduced phagocytic marker expression. Hematoma aspiration attenuated immunoproteasome expression and restored M2-associated and phagocytic signatures. Consistently, pharmacological inhibition of immunoproteasomes in primary microglia enhanced erythrophagocytosis and promoted a reparative phenotype in vitro. These findings indicate that immunoproteasome activation links hemorrhagic severity to maladaptive microglial polarization and impaired hematoma clearance after ICH, and that reducing immunoproteasome expression may help rebalance inflammatory and phagocytic microglial functions. Full article

Lepidoptera constitute a major group of agricultural and forestry pests. Therefore, investigating the immune mechanisms of the model species Bombyx mori may provide valuable insights for the development of improved pest management strategies. In insects, phenoloxidase (PO) and dopa decarboxylase (DDC) in immune melanization have been widely studied individually, yet their relative contributions have rarely been investigated. Here, we demonstrate that pharmacological inhibition of either PO or DDC in Escherichia coli-infected larvae significantly suppresses hemolymph melanization, with PO inhibition causing a more pronounced reduction than DDC inhibition. Consistently, RNA interference-mediated knockdown of BmPPO1 or BmPPO2 markedly decreased hemolymph melanization following infection. This results in both PO and DDC contributing to immune-induced hemolymph melanization, with PO playing a dominant role in this process. In contrast, compared to PO inhibition, DDC inhibition leads to significant damage to hemolymph antibacterial activity and cellular immune responses, including hemocyte aggregation, encapsulation, and phagocytosis. In addition, compared with the knockdown of BmPPO1 or BmPPO2, the knockdown of BmDDC leads to a more severe decrease in antibacterial activity and cellular immune function. Exogenous addition of dopamine can partially rescue cell damage, indicating that both DDC and PO play a role in cellular immunity, but DDC has a slightly stronger effect. Overall, this study provides important insights into the immunity of hemolymph in insects and other arthropods. Full article

Background: With the evolving paradigm of vaccine development, microcapsules have attracted considerable research interest as particulate adjuvants over the past decades. However, the rational engineering design of microcapsule-based composite adjuvant systems to elicit robust immune responses remains a significant challenge. Methods: This study developed polylactic acid (PLA) microcapsules with spatiotemporally coupled delivery and immunopotentiator properties. The resulting formulations were assessed for humoral and cellular immune responses in mice. Results: We prepared uniform-sized microcapsules (MC) and formulated them with monophosphoryl lipid A (MPLA) as a composite component (MPLA@MC), with hydrodynamic diameters of 4.58 μm and 4.12 μm, respectively. Such composite adjuvants, when loaded with ovalbumin (OVA) to form OVA@MC and OVA&MPLA@MC, promoted cellular uptake and activation, exhibiting preferred lysosomal escape advantages. For in vivo experiments, microcapsule-based vaccines elevated serum levels of IgG antibody, and OVA&MPLA@MC induced Th1-biased antibody responses. Specifically, OVA&MPLA@MC also elicited strong cellular immune responses compared to other vaccines, as evidenced by increased secretion of Interferon-γ (IFN-γ) in mouse splenocytes and Granzyme B (Gzmb) in T cells. Mechanistically, muscle tissues at the injection site showed that microcapsule-based vaccines enhanced the recruitment for phagocytosis. Meanwhile, bulk RNA sequencing (RNA-seq) confirmed extensive activation of immune responses and related signaling pathways. Conclusions: This rationally designed composite strategy for spatiotemporally coupled delivery serves as a potent platform for orchestrating synergistic immune responses, opening up new avenues for the development of effective therapeutic and anti-infectious vaccines. Full article

Cluster of Differentiation 47 (CD47) functions as a key “don’t-eat-me” signal that enables cancer cells to evade macrophage-mediated immune clearance. GV1001, a 16-amino-acid peptide derived from human telomerase reverse transcriptase (hTERT), has been reported to exhibit antitumor and anti-inflammatory properties and to downregulate CD47 expression in human cells. In this study, we investigated whether GV1001 modulated CD47 expression and enhanced antitumor immunity in oral squamous cell carcinoma (OSCC). In vitro, GV1001 significantly reduced CD47 expression in both murine and human OSCC cells in dose- and time-dependent manners, resulting in a marked increase in macrophage-mediated phagocytosis. Mechanistically, GV1001 suppressed CD47 promoter activity and inhibited multiple upstream regulator expression in murine and human OSCC cell lines, while exerting minimal effects on normal human keratinocytes and fibroblasts. In vivo, GV1001 significantly inhibited tumor growth, suppressed CD47 expression, increased macrophage infiltration, and induced tumor cell necrosis and apoptosis in both murine OSCC syngeneic graft model and human OSCC xenograft model. GV1001 administered alone or in combination with cisplatin produced antitumor effects. Collectively, these findings demonstrate that GV1001 functions as a potent immunomodulatory anticancer peptide that downregulates CD47 expression and restores macrophage-mediated tumor clearance, highlighting its potential as a therapeutic strategy for OSCC. Full article

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis, is a leading cause of morbidity worldwide. Along with CD4+ T lymphocytes, macrophages serve as key pillars of the immune response against this intracellular pathogen, which is essential for the prompt and effective elimination of the bacilli. Many strategies have been developed to enhance the microbicidal performance of macrophages; among them, stimulation with polymeric microparticles is one of the most promising. Exposition of infected macrophages to these microparticles may enhance non-specific innate immune mechanisms such as the promotion of phagocytosis, the induction of proinflammatory cytokines, and the production of reactive oxygen intermediates (ROI), contributing to the elimination of mycobacteria. Here, we evaluated the in vitro effect of starch microparticles (SMPs) on the activation and microbicidal activity of infected alveolar macrophages. The results demonstrate that these alpha-glucan microparticles are efficiently phagocytosed by infected macrophages and promote cellular activation, inducing reactive oxygen and nitrogen species, moderate apoptosis, and modulating cytokine and chemokine production without causing an excessive proinflammatory response. These effects contributed to the elimination of tubercle bacilli when SMPs were administered after infection, suggesting their usefulness as a post-exposure treatment that activates macrophages against the pathogen. Full article

Background/Objectives: Epigenetic modifications, particularly DNA methylation, contribute to tumor progression and therapy resistance. Guadecitabine, a hypomethylating agent (HMA), has shown promising clinical activity when combined with carboplatin in preclinical models. We evaluated the combination of guadecitabine with carboplatin as a second-line treatment for extensive-stage small-cell lung cancer (SCLC; NCT03913455), one of the deadliest malignancies. Here, we report methylome changes in peripheral blood mononuclear cells (PBMCs) collected at baseline and during treatment from patients on the trial. Methods: PMBC DNA was analyzed using Infinium HumanMethylationEPIC v1.0 bead chips. Data were processed, and differentially methylated positions (DMPs) were identified and analyzed for pathway enrichment using bioinformatic approaches, and immune deconvolution analyses were conducted to investigate the impact on immune cell composition. Results: Direct comparison of PBMCs between cycle 2 day 5 (C2D5; post-treatment) vs. cycle 1 day 1 (C1D1; pre-treatment) revealed a greater number of hypomethylated DMPs (380 DMPs in C2D5 vs. C1D1 PBMCs; p < 0.05, |β| > 20%). Moreover, when first compared with normal PBMCs from cancer-free controls, the number of hypomethylated DMPs was even greater in C2D5 than in C1D1 (1771 vs. 237 DMPs, respectively; p < 0.05, |β| > 20%). Long interspersed nucleotide elements-1 (LINE-1) were significantly hypomethylated in PBMCs after HMA treatment (C2D5 vs. C1D1). Pathway analysis of hypomethylated DMPs revealed significant alterations in key signaling pathways, including NF-κB, Rho GTPase, and pulmonary fibrosis in C1D1 vs. C2D5. Normal PBMCs to C1D1 PBMCs revealed changes in IL-3 signaling, Fcγ receptor-mediated phagocytosis, and molecular mechanisms of cancer. Deconvolution analysis revealed a greater percentage of monocytes in C1D1 vs. normal PBMCs; after HMA treatment, percentages of monocytes and B cells decreased, while the eosinophil percentage increased in C1D1 vs. C2D5. Conclusions: HMA treatment has a global impact on PBMC methylomes in cancer patients. DNA methylation changes were associated with biological pathways related to PBMC function, and shifts in distinct immune cell populations were observed. Full article