Search Results (3,770)

Uncontrolled inflammation contributes to the development of neurodegenerative diseases (NDs) like Alzheimer’s disease (AD). N-(p-Coumaroyl) serotonin (CS) has demonstrated a significant capacity to modulate hyper-inflammation. We explored whether CS could mitigate inflammatory responses in endotoxin-challenged microglial cells and sought to elucidate the specific molecular mechanisms governing these effects. ELISA, nitric oxide (NO) assays, Western blotting and immunocytochemistry were performed to study inflammatory responses and related signal transduction mechanisms. CS pretreatment effectively attenuated the inflammatory output in endotoxin-primed microglial models. This was evidenced by a significant reduction in key cytokines (such as IL-6, TNF-α, and MCP-1) and a concomitant decrease in the protein levels of iNOS and COX-2. These effects were mediated through the disruption of MAPK/NF-κB signaling cascades and the sequestration of NF-κB within the cytoplasm. Beyond its anti-inflammatory role, CS promoted the HO-1/NQO1 signaling pathway and interfered with the LPS-mediated TLR4/MyD88 cascade. Our collective evidence indicates that the modulation of microglia-mediated inflammation by CS is underpinned by the suppression of MAPK/NF-κB and the induction of antioxidant systems, suggesting that CS may have the potential to improve NDs. Full article

Background: Inonotus obliquus (Chaga), a medicinal and edible macrofungus abundant in bioactive polyphenols, is a potential source of natural antioxidants and anti-inflammatory agents for functional foods. This study aimed to evaluate the antioxidant capacity of three key polyphenols (osmundacetone [OS], protocatechuic aldehyde [PAH], protocatechuic acid [PA]) from I. obliquus and decipher their anti-inflammatory mechanisms via the MyD88/TLR4/NF-κB pathway in a gout-related model. Methods: Antioxidant activity was assessed by xanthine oxidase (XO) inhibition (IC₅₀), superoxide anion (O₂⁻) scavenging, and structure–activity relationship (SAR) analysis; in a monosodium urate (MSU)-induced acute gout cell model, reactive oxygen species (ROS), nitric oxide (NO), lactate dehydrogenase (LDH), superoxide dismutase (SOD), pro-inflammatory cytokines (TNF-α, IL-1β) were quantified, and MyD88/TLR4/NF-κB pathway proteins were analyzed by Western blot. Results: OS showed the strongest XO inhibition (IC₅₀ = 4.91 mM), followed by PAH (IC₅₀ = 5.92 mM) and PA (IC₅₀ = 26.53 mM); OS exerted dual redox effects by scavenging O₂⁻ and suppressing XO-mediated O₂⁻ generation, with its conjugated C=C-carbonyl system and PAH’s aldehyde group enhancing XO binding. All polyphenols and I. obliquus crude extract significantly reduced ROS, NO, LDH, and cytokines (p < 0.05), increased SOD, and downregulated TLR4, MyD88, and NF-κB expression. Conclusions: I. obliquus-derived polyphenols exhibit obvious antioxidant and xanthine oxidase inhibitory effects, and regulate oxidative stress, pro-inflammatory mediators, and the MyD88/TLR4/NF-κB signaling pathway in monosodium urate-stimulated RAW 264.7 inflammatory macrophages, supporting their development as natural functional food ingredients and potential candidates for gout-related and oxidative stress-associated inflammatory cellular disorders. Full article

Background/Objectives: Vaccines targeting melanoma antigens can elicit CD8⁺ T cell responses, but a growing body of work suggests CD4⁺ T cells also play a role in tumor control. Induction of CD4⁺ cells may also support B cells in producing tumor antigen-specific antibodies (Abs). We investigated Abs induced by vaccination with a cocktail of six class II MHC-restricted melanoma peptides (6MHP) and the effect of adjuvant type on Ab isotypes. We hypothesized that the vaccines would induce Abs that respond to different epitopes on individual peptides and that IgG isotype distribution varies with different vaccine adjuvants. Methods: Sera from patients who received a 6MHP vaccine were evaluated with enzyme-linked immunosorbent assays to map epitopes for polyclonal Ab responses to synthetic melanoma peptides. IgG isotypes of Ab responses to 6MHP were assessed in patients who received one of four adjuvants (Incomplete Freund’s Adjuvant (IFA) alone, IFA + polyICLC, IFA + systemic metronomic cyclophosphamide (mCy), or IFA + polyICLC + systemic mCy) to characterize IgG isotype distribution. Results: Epitope mapping revealed that at least 50% of patients had responses to two or more epitopes on the same peptide, suggesting polyclonal Ab responses. Serum evaluation for IgG isotypes showed predominant induction of IgG1 and IgG3. Mean total IgG was highest when IFA and polyICLC were used in combination. Patients who received TLR3 agonist polyICLC had significantly higher concentrations of total IgG, IgG1, and IgG3 compared to patients who did not receive polyICLC. Conclusions: Vaccine-induced Abs may respond to multiple epitopes within the same peptide, warranting further studies into their ability to facilitate antigen uptake and presentation through the formation of large immune complexes. The findings also show that adding polyICLC to IFA can significantly enhance Ab responses. Collectively, this work underscores the immunologic potential of peptide-induced Abs and the importance of adjuvant selection in cancer vaccine design. Full article

Alzheimer’s disease (AD) is traditionally defined by Amyloid-β (Aβ) plaques and tau neurofibrillary tangles, yet these proteinopathies alone fail to explain disease heterogeneity, progression, and cognitive decline. Emerging evidence identifies chronic neuroinflammation as a central integrator that converts molecular pathology into synaptic failure and neurodegeneration. In this context, Aβ acts as a danger-associated molecular pattern that activates microglial and astrocytic immune programs through receptors such as TREM2, TLRs, and RAGE, leading to inflammasome activation, cytokine release, and oxidative stress. These responses pathologically re-engage developmental complement pathways (C1q–C3–CR3), driving excessive synaptic pruning that correlates more closely with cognitive impairment than neuronal loss. Reactive astrocytes further amplify dysfunction by impairing glutamate and potassium homeostasis, promoting excitotoxic and metabolic stress, while inflammatory glia facilitate prion-like tau propagation via extracellular vesicles. Concurrent neurovascular inflammation disrupts blood–brain barrier integrity and cerebral perfusion, reinforcing immune-metabolic failure. Importantly, neuroinflammatory biomarkers (GFAP, sTREM2, YKL-40, cytokines, complement, and TSPO-PET) provide dynamic readouts of disease activity and therapeutic response. Together, these findings position AD as a disorder of failed immune resolution and support precision immunomodulatory and pro-resolving therapies aimed at restoring neuroimmune homeostasis rather than merely removing protein aggregates. Full article

Influenza’s pandemic threat is driven by antigenic drift, which limits the efficacy of conventional vaccines. To address this challenge, we established a clinical serum-anchored computational design pipeline for a broad-spectrum multi-epitope mRNA vaccine (MEMV), bridging the gap between pure in silico design and clinical applicability. Using 36 longitudinal sera (d0/d28/d365) from 12 well-characterized human cohorts (6 vaccine recipients and 6 influenza patients) and high-density antibody-peptide microarrays, we empirically identified 12 immunodominant B-cell linear epitopes from the nucleoprotein (NP) of influenza A (H1N1/H3N2) and B viruses. These experimentally validated epitopes were combined with in silico-predicted conserved helper T-lymphocyte (HTL)/cytotoxic T-lymphocyte (CTL) epitopes (from NP/HA/NA) to construct MEMVs candidates, ensuring high antigenicity, non-toxicity, and 95.63% global HLA coverage. Molecular docking and 100 ns molecular dynamics (MD) simulations confirmed favorable conformational compatibility between MEMVs and Toll-like receptor 3 (TLR3) in silico immunization via C-ImmSim predicted robust B/T-cell responses and protective cytokine (IFN-γ/IL-10) production. Collectively, this pipeline shortens the preliminary design cycle for influenza vaccines, provides a standard epitope-combination strategy, and offers direct targets for follow-up in vitro/in vivo experiments. Full article

Emerging mosquito-borne flaviviruses, such as Dengue virus (DENV) and Zika virus (ZIKV), pose major global public health threats due to their geographic expansion, climate change, and the absence of effective antiviral therapies. Antiviral development against these pathogens has primarily focused on two complementary strategies. On the one hand, the blocking of viral replication by directly inhibiting essential viral enzymes, and on the other, enhancing the host’s innate immune defenses via targeted activation of intracellular antiviral pathways. Among the viral proteins required for replication, the NS2B–NS3 protease complex is one of the most conserved and druggable targets, prompting extensive efforts to design both covalent and non-covalent inhibitors. Covalent inhibitors, such as boronic acids, aldehydes, trifluoromethyl ketones, phenoxymethylphenyl derivatives, and α-ketoamides, form irreversible or slowly reversible bonds with the catalytic serine residue (Ser 135), producing long-lasting and high-affinity suppression of protease activity. In parallel, several classes of non-covalent, particularly allosteric, inhibitors have emerged as promising alternatives with improved specificity and reduced off-target reactivity. A complementary antiviral strategy involves the use of agonists of key innate immune sensors such as TLRs, RIG-I, and the cGAS–STING axis, which mediate the release of interferons (IFNs). This review brings together current knowledge on these two mechanistically distinct yet convergent approaches, highlighting how both can ultimately restrict flavivirus replication. Future opportunities involving modified peptide scaffolds, advanced delivery systems, and drug-repurposing strategies are finally discussed for the development of next-generation therapeutics against DENV and ZIKV. Full article

Objectives: Carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) merges multidrug resistance with hypervirulence, posing unprecedented therapeutic challenges. This study aimed to evaluate the efficacy of a recombinant fusion protein vaccine, KPC-Pal, designed to target both the carbapenemase KPC-2 and the virulence-associated peptidoglycan-associated lipoprotein Pal. Methods: The KPC-Pal fusion protein was constructed, expressed, and purified. Its protective efficacy was systematically assessed in a murine pneumonia model by measuring antigen-specific antibodies, cytokine profiles, and memory cell populations. The synergistic effect with the antibiotic meropenem was evaluated both in vitro and in vivo. Furthermore, the interaction with innate immune signaling via TLR2 was investigated. Results: Immunization with KPC-Pal conferred superior protection, resulting in significantly higher survival rates and reduced bacterial burdens in the lungs compared to immunization with either KPC-2 or Pal alone. It induced a robust Th2-biased humoral response and a mixed Th1/Th2/Th17 cellular immune profile, along with enhanced formation of tissue-resident memory T cells. Antibodies generated against KPC-Pal enhanced the efficacy of meropenem in vitro and in animal models, demonstrating a synergistic effect. While Pal alone strongly activated TLR2-driven inflammatory pathways, the KPC-Pal fusion selectively modulated MAPK signaling, mitigating excessive cytokine production. Additionally, KPC-Pal vaccination elicited cross-reactive antibodies against KPC-3 and KPC-33 variants. Conclusions: KPC-Pal functions as both an antigen and a self-adjuvant, offering a promising dual-target strategy for combating K. pneumoniae infections. Full article

This study aimed to investigate the effect of lipopolysaccharide challenge on growth performance and immune function in yellow-feathered broilers. A total of 140 yellow-feathered broilers (1-day-old) were randomly assigned to two treatments (control group and LPS group) with seven replicates of 10 chicks each. Broilers in the LPS group were injected intraperitoneally with LPS (1 mg/kg body weight) on days 21, 23, 25, and 27, while broilers in the control group were injected intraperitoneally at an equivalent volume of sterile saline on the corresponding days. After 24 hours of each injection, one chicken from each replicate was randomly selected for slaughter and sampling. The results indicate that the first LPS challenge significantly elevated jejunal mucosal IL-6 levels compared with the control group (p < 0.05). After the second injection, average daily feed intake (ADFI), average daily weight gain (ADG), and body weight gain (BWG) of broilers were decreased in the LPS group compared to the control group (p < 0.05). Additionally, IL-1β levels were increased in the liver and jejunal mucosa of broilers in the LPS group (p < 0.05). After the third injection, the ADFI, ADG, BWG and feed conversion ratio (FCR) were reduced in the LPS group compared to the control group. LPS also caused a decrease in the broiler thymus index and bursa index. In addition, the levels of IL-1β, IL-6 and IFN-γ in the jejunal mucosa of broilers in the LPS group were higher than those in the control group (p < 0.05). The levels of IL-1β and IFN-γ in the liver of the LPS group were significantly higher than those of the control group (p < 0.05). The mRNA expression of IL-1β, IL-6, and IFN-γ in the jejunum and liver of the LPS group was significantly higher than that of the control group (p < 0.05). Furthermore, the mRNA expression of TLR4 and MyD88 in both the liver and jejunal mucosa of broilers in the LPS group was significantly higher than that in the control group (p < 0.05). Following the fourth LPS injection, the ADFI, ADG, BWG, and spleen index of LPS group decreased significantly compared to the control group. Concurrently, a significant increase in the content of IFN-γ in the liver was observed. In conclusion, three times of LPS stimulation can cause significant immune damage and induce an immune stress model. Full article

Trollius chinensis Bunge (TCB), a perennial Ranunculaceae herb, produces Flos Trollii-dried flowers with medicinal properties including heat clearing, detoxification, and relieving oral/throat discomfort, eye pain, and cold-induced fever. TCB is mainly cultivated in northern China, while Trollius ledebouri Rchb. (TLR), distributed in Heilongjiang’s Great Xing’an Mountains, is morphologically similar to TCB. However, their regulatory statuses are inconsistent, and comprehensive comparative studies are lacking. This study adopted morphological assessment, microscopy, DNA barcoding, and physicochemical analysis to explore whether TLR could be a potential alternative source of Flos Trollii. Key differences were identified: TLR’s sepals are shorter than petals, whereas TCB’s sepals and petals are nearly equal in length; TLR has brown secretory structures absent in TCB. Genetic distance analysis showed high conservation in ITS2 and trnL-trnF sequences between the two species, but psbA-trnH sequence divergence exceeded the 0.05 threshold. HPLC quantification revealed that TLR contained slightly higher levels of orientin and vitexin than TCB. HPLC quantification revealed that TLR contained slightly higher levels of orientin (5.370–5.377 mg/g) and vitexin (1.954–2.053 mg/g) compared to TCB (orientin: 4.493–4.620 mg/g; vitexin: 1.361–1.451 mg/g). Collectively, TLR exhibits comparable flavonoid content and holds potential as an alternative Flos Trollii source. Given the limited bioactive compounds analyzed, future research should conduct comprehensive metabolomic profiling to fully evaluate its phytochemical composition and medicinal value. These data establish chemotaxonomic markers for Trollius authentication in herbal medicine. Full article

Background: Hepatic ischemia-reperfusion injury (HIRI) is a major complication in liver surgery with limited therapeutic options. Houttuynia cordata polysaccharide (HCP), a key bioactive component of the traditional anti-inflammatory herb, has demonstrated immunomodulatory potential, but its effect on HIRI remains unclear. Methods: A murine model of 70% hepatic ischemia for 60 min followed by reperfusion was established. Mice were administered low-dose (50 mg/kg) or high-dose (100 mg/kg) HCP or the positive control N-acetylcysteine (150 mg/kg). Liver injury was assessed by serum ALT/AST levels, histopathology, oxidative stress markers, and inflammatory cytokines. Macrophage polarization and the TLR4/NF-κB pathway were analyzed using flow cytometry, qPCR, and Western blot. The TLR4 inhibitor TAK-242 was used for reverse validation, and molecular docking was performed to predict HCP binding to the TLR4/MD-2 complex. Results: HCP significantly attenuated HIRI-induced liver injury, as shown by reduced ALT/AST, improved histopathological scores, decreased MDA, increased SOD, and lower TNF-α and IL-6 levels. Mechanistically, HCP promoted a shift from M1 to M2 macrophage polarization, with increased CD206⁺ cells and Arg-1/IL-10 expression and decreased CD86⁺ cells and iNOS/IL-1β expression. HCP also suppressed TLR4/MyD88/NF-κB pathway activation, inhibiting NF-κB p65 phosphorylation and nuclear translocation. These protective effects were largely reversed by TAK-242 in vivo and in vitro. Molecular docking indicated stable binding between HCP and TLR4/MD-2. Conclusions: HCP protects against HIRI by targeting TLR4 to inhibit NF-κB signaling, thereby reprogramming macrophage polarization toward the M2 phenotype and alleviating inflammation and oxidative stress. These findings highlight HCP as a promising natural agent for HIRI intervention. Full article

The complement system is a central component of innate immunity with established roles in host defense and emerging functions in neurodevelopment, synaptic remodeling, and neuroimmune communication within the central nervous system (CNS). In parallel, advances in nanotechnology have not only enabled targeted strategies for CNS drug delivery but have also revealed that many nanomaterials interact with and activate complement, influencing biodistribution, safety, and inflammatory responses. Opioid use disorder (OUD) is increasingly recognized as a condition associated with chronic neuroimmune dysregulation involving glial activation, altered cytokine signaling, and blood–brain barrier (BBB) disruption. However, direct experimental or clinical measurements of complement activation in OUD remain limited. Current evidence linking complement pathways to opioid exposure is derived largely from indirect observations, including transcriptomic alterations, glial phenotypes, and inflammatory signatures in preclinical and translational models, which collectively suggest, but do not yet definitively establish, complement involvement in opioid-induced neuroimmune signaling. This review synthesizes current knowledge at the intersection of complement biology, nanomedicine, and opioid-associated neuroimmune changes. It distinguishes well-established mechanisms of complement activation by nanomaterials from emerging and inferential evidence linking complement signaling to opioid exposure. This hypothesis-generating framework integrates complement signaling with opioid receptor and TLR4 pathways in glial and endothelial compartments, examining their potential protective and pathological CNS roles while outlining the translational promise and current evidence gaps of complement-aware nanotechnologies for addiction neuroscience. Full article

Viruses of the family Anelloviridae represent a predominant component of the human virome across various anatomical sites, yet their clinical significance remains poorly understood. This review summarizes current data on the dynamics and functional interactions of anelloviruses with the immune system in the context of human immune deficiency virus (HIV) infection. Existing studies indicate that an individual’s complement of anelloviruses (their “anellome”) serves as a highly sensitive indicator of immunocompetence. In the absence of antiretroviral therapy (ART), the viral load and taxonomic diversity of anelloviruses (genera Alphatorquevirus, Betatorquevirus, and Gammatorquevirus) demonstrate a rapid increase, correlating with HIV viral load, a decline in CD4+ T-lymphocyte count, and the CD4/CD8 ratio, reflecting weakened immune surveillance. Upon initiation of antiretroviral therapy (ART), a decrease in anellovirus viral load is observed; however, it likely does not revert to the pre-HIV infection baseline. At the same time, a high baseline level of Torque teno virus (TTV) is associated with incomplete immune recovery and the risk of ART non-response. Anelloviruses exhibit a dual role as both activators of the immune system (via APOBEC3, antibody production, and pro-inflammatory cytokines resulting from Toll-like receptor (TLR) activation) and disruptors of certain signaling pathways (through micro-RNAs and proteins encoded by ORF2). Thus, monitoring the anellome represents a promising non-invasive approach for assessing immune status, risk stratification, and personalizing therapy in patients with HIV infection. Future research should focus on the practical application of anellovirus viral load and diversity as markers of immune status and on clarifying the consequences of the aggregate interaction between HIV modulator proteins and anelloviruses during co-infection. Full article

Hepatitis C virus (HCV) chronically infects over 50 million people worldwide and poses a significant risk to global health. The HCV NS3/4A complex, a bifunctional enzyme comprising a protease and a helicase domain, is indispensable for viral replication and immune evasion, making it a pivotal target for direct-acting antiviral agents (DAAs). Here, we summarize its structural features, functional mechanisms, and implications in drug design and protein engineering (e.g., nanopore sequencing applications). The NS3 protease domain is activated by the NS4A cofactor, which mediates viral polyprotein processing and relies on a zinc-binding site for structural stability. The C-terminal helicase domain catalyzes ATP-dependent 3′→5′ unwinding, and allosteric crosstalk between the protease and helicase domains dynamically modulates the enzymatic activity, balancing unwinding velocity and processivity. Beyond supporting viral replication, NS3/4A cleaves MAVS to abolish RIG-I/MDA5 signaling but spares TRIF, leaving TLR3-mediated immunity intact; it also modulates host lipid and iron metabolism, contributing to HCV pathogenesis. Notably, structural and functional studies of NS3/4A lay a solid theoretical foundation for developing novel therapeutic strategies. Currently, DAAs targeting NS3/4A have achieved high sustained virologic response rates; however, resistance-associated substitutions remain a major clinical challenge, particularly in genotype 3 infections. Emerging therapeutic strategies targeting NS3/4A include allosteric inhibition and proteolysis-targeting chimeras (PROTACs)-mediated degradation. Full article

Cutibacterium acnes, a major skin commensal bacterium, induces inflammatory cytokine production in keratinocytes through Toll-like receptor 2 (TLR2) signaling and contributes to acne vulgaris pathogenesis. Although glucocorticoids, e.g., dexamethasone (Dex), exert anti-inflammatory effects in related treatments, prolonged glucocorticoid exposure paradoxically induces acneiform eruptions, a phenomenon referred to as steroid-induced acne. Moreover, how commensal fungi influence bacterial-driven inflammatory signaling under glucocorticoid treatment remains unclear. In this study, we investigated how the lipophilic skin yeast Malassezia restricta affects C. acnes-induced TLR2 expression under Dex treatment using normal human epidermal keratinocytes. We discovered that M. restricta selectively suppressed Dex-enhanced C. acnes-induced TLR2 expression both at the transcriptional level and cell surface. Mechanistically, M. restricta enhanced p38 MAPK phosphorylation and inhibited NF-κB p65 nuclear translocation, indicating context-dependent glucocorticoid-primed TLR2 signaling modulation rather than simple inhibition. These results demonstrate that M. restricta modulates bacterial-induced inflammatory responsiveness in keratinocytes under glucocorticoid exposure and highlight the importance of fungal–bacterial interactions in shaping host immune signaling in steroid-treated skin. Our study provides new insight into the mechanistic basis of steroid-induced acne and the polymicrobial regulation of cutaneous innate immunity. Full article

Background: Cardiovascular disease (CVD) remains the leading global cause of mortality, with endothelial dysfunction as an early driver of pathology. Periodontal disease (PD) and its pathogen Porphyromonas gingivalis (Pg) are increasingly associated with metabolic disturbances and vascular injury, yet the combined impact of microbial and dietary stressors has not been mechanistically defined. Methods: In this 24-week study, mice were subjected to chronic Pg infection with or without a high-fat diet (HFD). Metabolic profiling, cytokine analyses, molecular signaling assessments, and ex vivo vascular reactivity studies were performed to evaluate systemic and vascular outcomes. Results: Pg infection induced metabolic alterations and vascular inflammation, while HFD alone caused obesity, insulin resistance, dyslipidemia, and impaired endothelial relaxation. Combined Pg infection and HFD produced the most severe phenotype, with synergistically elevated cytokines, heightened TLR4/NF-κB activation, marked suppression of PPARγ and Nrf2 signaling, reduced eNOS expression, and diminished nitric oxide bioavailability. Cinnamaldehyde (CNM) supplementation improved metabolic indices, reduced inflammatory cytokines, restored PPARγ and Nrf2 activation, enhanced Akt-mediated eNOS phosphorylation, and normalized endothelial-dependent vasorelaxation. Conclusions: Pg infection and HFD act as synergistic metabolic and vascular stressors that accelerate endothelial dysfunction through coordinated disruption of PPARγ/Akt/eNOS and Nrf2 pathways, while CNM provides substantial protective effects. Full article