Search Results (23,930)

Human metapneumovirus (HPMV) is a significant pathogen that causes lower respiratory tract infections. Given the weak immunogenicity thereof, and the few relevant studies, the utility of the viral membrane protein G as a vaccine remains controversial. In this study, the G extracellular domain (RMG) of HMPV was expressed either alone or fused with the cholera toxin B subunit (CTB) and “cross-reacting material 197” (CRM197) carrier proteins (giving G-CTB/G and CRM197), to enhance immunogenicity. The non-glycosylated G protein (REG) expressed in Escherichia coli served as a control. SDS-PAGE and anti-His tag Western blotting verified that each protein was successfully expressed and correctly identified. BALB/c mice were immunized with each protein and subjected to challenge with HMPV. The results showed that, although immunization with RMG alone failed to induce potent neutralizing antibodies, it modestly reduced viral loads in the lungs of mice. However, the pathological damage caused by lung inflammation was more aggravated than that of the control challenge group. The level of specific IgG antibody induced by the recombinant G-CTB was significantly higher than that elicited by RMG. Compared to the RMG group, the viral load in the lungs of the G-CTB group tended to be reduced. Also, the damage caused by lung inflammation was significantly alleviated. Our study proves that HMPV G may be a valuable antigen in terms of HMPV vaccine development and offers a promising strategy for modulating the immunogenicity and safety thereof. Full article

This study characterizes novel cross-linked polymeric composites based on bisphenol A glycerolate dimethacrylate (BPA.DM) as the primary matrix, incorporating 1-vinyl-2-pyrrolidone (NVP) or 2-hydroxyethyl methacrylate (HEMA) as active diluents, and modified with antimicrobial agents: zinc oxide (ZnO), copper(II) sulfate (CuSO₄), nanosilver (Ag), and benzethonium chloride (BEN). Release kinetics of active components into water and LH medium were measured over 20 days using HPLC (bisphenol A, benzethonium chloride), GF AAS (Cu, Zn, Ag), and GC–MS, revealing highest silver release from HEMA+Ag composites (1671 µg/L), substantial copper release from HEMA (354 mg/L) and NVP (319 mg/L) systems, while benzethonium chloride exhibited significantly lower migration. The effect of NVP- and HEMA-containing composites on the metabolism of the Cerrena unicolor was also assessed. Scanning electron microscopy (SEM) and optical profilometry confirmed extensive surface degradation by C. unicolor mycelium, manifesting as cracks, increased porosity, and altered surface across HEMA- and NVP-based composites after 21-day incubation. Biochemical analysis of the fungus post-culture liquids demonstrated that both composite types markedly enhanced extracellular laccase activity at all tested time points (7, 14, 21 days), with ethanol-sterilized samples inducing a slower-migrating laccase isoform identified via zymography. These materials also increased total protein concentration and superoxide anion radical levels while reducing phenolic compounds relative to controls. The findings demonstrate that antimicrobial-modified BPA.DM composites not only undergo controlled biodegradation by C. unicolor but crucially serve as potential laccase inducers, highlighting their dual utility in bioactive material design and fungal enzyme biotechnology. Full article

Advances in mass spectrometry-based metabolomics have enabled the detection of numerous small molecules in biological systems, revealing complex metabolic alterations associated with cancer. Among these, dipeptides are consistently detected in plasma, serum, and tumor tissue metabolomic profiles, yet their biological significance is not fully understood. In most studies, circulating dipeptides are interpreted as nonspecific byproducts of protein degradation generated during increased proteolysis. However, accumulating evidence suggests that at least some endogenous dipeptides may have biological activities, including antioxidant effects, metabolic modulation, and potential signaling functions. In this review, we examine the possible origins, transport mechanisms, and biological implications of circulating dipeptides in cancer metabolomics. We discuss multiple sources of dipeptide generation, including intracellular proteolysis, autophagy, extracellular matrix remodeling, tumor cell death, host tissue catabolism, and microbiome metabolism. We also summarize current knowledge regarding peptide transport systems and intracellular dipeptide metabolism that may regulate the fate of these molecules within mammalian systems. In addition, evidence supporting the biological activities of certain endogenous dipeptides is reviewed to evaluate the possibility that some circulating dipeptides may function as bioactive metabolites. Finally, we propose conceptual frameworks for interpreting circulating dipeptides in cancer, including their potential roles as indicators of protein turnover, intermediates in amino acid recycling, stress-buffering molecules, metabolic signals, or components of tumor–host metabolic communication. A better understanding of circulating dipeptides may provide new insights into cancer metabolism and reveal previously overlooked metabolite classes with potential biomarker or functional significance. Full article

Metabolic syndrome (MetS) drives cardiac remodeling and fibrosis, contributing to diastolic dysfunction and heart failure with preserved ejection fraction, but chamber-specific mechanisms remain poorly defined. New Zealand White rabbits were fed a high-fat/high-sucrose diet for 28 weeks to induce experimental MetS. Systemic phenotype, cardiac structure (echocardiography), myocardial fibrosis (Picrosirius red histology), myosin/collagen gene expression (qRT-PCR), and chamber-specific proteomics were assessed across left/right atria and ventricles. The model reproduced central obesity, glucose intolerance, dyslipidemia, and mild hypertension, with concentric left ventricular hypertrophy and selective ventricular fibrosis, as follows: increased collagen in left ventricle (LV) and right ventricle (RV), unchanged in atria. Ventricular α-myosin heavy-chain gene expression was upregulated, while collagen I and α-smooth muscle actin transcripts showed ventricular-specific downregulation. Proteomics revealed atrial metabolic and cytoskeletal adaptations with minimal extracellular matrix involvement; ventricles displayed early profibrotic cues (galectin-3 in LV), metabolic inefficiency (impaired glycolysis/ATP production in LV; lipid oxidation shift in RV), and diminished provisional matrix support. Conclusions: concentric LV hypertrophy and great vessel enlargement occurred without systolic/diastolic dysfunction; ventricular-selective fibrosis, α-myosin heavy-chain upregulation, type I collagen/α-smooth muscle actin downregulation, and chamber-specific proteomic changes showed atrial adaptation versus ventricular early profibrotic/metabolic inefficiency. Full article

Background: Eosinophilic chronic rhinosinusitis (ECRS) is characterized by refractory nasal polyps and severely impaired mucociliary clearance (MCC). The molecular mechanisms underlying the modulation of mucociliogenesis following IL-4/13 blockade with dupilumab remain poorly understood, notwithstanding its proven clinical efficacy. Methods: Bulk RNA Barcoding and sequencing (BRB-seq) was performed on nasal polyp tissues collected from healthy controls (n = 6), patients with non-ECRS (n = 8), and patients with ECRS both before and four weeks after dupilumab treatment (n = 9) to identify the early molecular drivers underlying ciliary regeneration. Comprehensive gene-set scoring systems were developed to evaluate multiciliogenesis master regulators, master regulators of core/ciliary planar cell polarity (PCP) and PCP components. Interaction scores for epithelial-derived cytokines—thymic stromal lymphopoietin (TSLP), IL-25, and IL-33—were calculated based on ligand and cognate receptor subunit expression. Results: The ciliary master regulatory hierarchy (e.g., FOXJ1, RFX2/3), PCP components (CELSR1 and the ciliogenesis and planar polarity effector (CPLANE) module: FUZ, INTU, WDPCP), and structural ciliogenesis pathways were robustly restored following IL-4/13 blockade. The TSLP interaction score correlated with global mucosal damage, serving as a trigger for compensatory multiciliogenesis. The pre-treatment IL-33 interaction score emerged as a significant predictor of transcriptomic ciliary recovery (p < 0.05). DNASE1L3—the primary endonuclease for degrading eosinophilic extracellular traps (EETs)—remained persistently downregulated post-treatment. Conclusions: IL-4/13 blockade successfully restores the structural and directional “hardware” of the respiratory epithelium but fails to rectify the enzymatic “software” required for mucus degradation. This “residual molecular scar” may explain the persistent mucus hyperviscosity observed in some ECRS patients even after clinical polyp resolution. Full article

The tumor microenvironment (TME) is a highly adaptive and heterogeneous niche in which cancer stem cells (CSCs) promote immune evasion, metastatic dissemination, and therapy resistance. Among the mechanisms that support this phenotype, mitochondrial hijacking has emerged as a central strategy through which CSCs reprogram immune and stromal cells to favor tumor progression. This review synthesizes current evidence on how CSCs exploit mitochondrial transfer, particularly via tunneling nanotubes (TNTs) and extracellular vesicles (EVs), to impair antitumor immunity and remodel the metastatic niche. CSCs display marked metabolic plasticity, shifting between glycolysis and oxidative phosphorylation (OXPHOS) in response to environmental stress. They exploit this adaptability by transferring mitochondria and mitochondrial components to recipient cells, including tumor-associated macrophages (TAMs) and cytotoxic T cells, thereby disrupting ATP production, increasing oxidative stress, and skewing immune polarization. This mitochondrial hijacking contributes to an immunosuppressive milieu, stabilizes HIF-1α, and enhances PD-L1 expression, ultimately weakening T-cell activity and reinforcing CSC survival. EVs add another layer of regulation by transporting bioactive cargo, including oncogenic microRNAs (miRNAs) and mitomiRs such as miR-21, miR-210, and miR-34a. These molecules modulate mitochondrial gene expression, reshape immune signaling, and reinforce CSC phenotypes through autocrine and paracrine loops. Single-cell and spatial transcriptomic approaches have further revealed metabolic heterogeneity within CSC–immune synapses, identifying “metabolic hotspots” associated with profound immune dysfunction. Therapeutic strategies targeting OXPHOS, EV biogenesis, and miRNA activity are therefore being explored. In parallel, mitochondria-associated proteins such as TSGA10 may also contribute to CSC-driven immunometabolism regulation and deserve further investigation. Targeting downstream heterogeneity is like cutting the branches of a weed. Targeting the upstream mechanisms of mitochondrial hijacking and miRNA crosstalk aims to destroy the root (CSC plasticity) that generates the heterogeneity and drives therapy resistance in the first place. This review highlights mitochondrial hijacking and miRNA-mediated reprogramming as central determinants of CSC-driven immune escape and proposes a framework for precision interventions targeting CSC–immune interactions in metastatic cancer. Full article

The recent rise in whole blood usage for traumatic hemorrhagic shock has renewed interest in the impact of leukocytes on hemostatic function during cold storage. This study investigated whether tissue factor (TF)-bearing extracellular vesicles (EVs) are released from human monocytic cells during cold storage or upon rewarming and whether this process is mechanistically linked to apoptosis. We further examined the contribution of superoxide anion generated by NADPH oxidase (NOX). Methods: THP-1 cells were incubated at 4 °C for up to 24 h with/without test reagents and subsequently rewarmed at 37 °C. Cells were washed by centrifugation before rewarming as required. TF activity in the cell supernatant was quantified, EVs were analyzed by flow cytometry with size-defined gating, and NOX activity normalized to p22^phox was measured by cytochrome c reduction. Results: TF levels and apoptotic cells increased during cold storage. TF release was enhanced 1–2 h after cell lavage following cold exposure, indicating active shedding of TF-bearing EVs rather than passive leakage from damaged membranes. Flow cytometry demonstrated that TF-bearing EVs were distinct from apoptotic vesicles, with a substantial proportion falling within the microvesicle size range. Cold exposure enhanced NOX activity. Both superoxide dismutase (SOD) and catalase inhibited TF release during cold storage; however, only SOD suppressed TF release after cell lavage. Conclusions: TF-bearing EVs are actively shed from human monocytic cells during and after cold storage via a NOX-dependent, superoxide-mediated mechanism. Extracellular SOD suppressed this procoagulant EV release, suggesting a potential strategy to modulate hemostatic alterations associated with cold-stored blood. Full article

Akkermansia muciniphila (A. muciniphila) is a bacterium that breaks down mucus and is studied for its effects on metabolism and the immune system. Studies show that it affects Alzheimer’s disease (AD) by protecting the gut barrier, reducing inflammation, and influencing communication between the immune system, the brain, and mitochondria. This review summarizes mechanistic, preclinical, and translational evidence connecting A. muciniphila to AD, including products such as short-chain fatty acids (SCFAs), and structural or secreted proteins including Amuc_1100 and extracellular vesicles (AmEVs). We also discuss differences between bacterial strains, differences in research methods, and findings that change under different conditions, which make the results harder to interpret. Animal studies suggest neuroprotective effects, but clinical evidence is still limited. Clinical use will need human studies at the strain level, confirmation in humanized models, and early trials using biomarkers to test safety and causal effects. Full article

Bacterial membrane vesicles (BMVs), encompassing outer membrane vesicles (OMVs) released from Gram-negative bacteria and extracellular vesicles (EVs) released from Gram-positive bacteria, have emerged as promising vaccine platforms owing to their intrinsic immunostimulatory properties and capacity to deliver a wide range of antigens. Although conventional vaccines effectively prevent infectious diseases, their long-term efficacy is often limited by antigenic variation and reliance on a restricted number of licensed adjuvants. BMVs, as self-adjuvanting systems, enable both antigen delivery and innate immune activation. BMVs are nanoscale lipid bilayer structures enriched with pathogen-associated molecular patterns (PAMPs), facilitating their recognition and uptake by antigen-presenting cells. This leads to the activation of pattern recognition receptors and the induction of pro-inflammatory cytokines, type I interferons, and adaptive immune responses, including antibody production and Th1- and Th17-biased cellular immunity. Recent studies highlight the versatility of BMVs as vaccine platforms across bacterial, fungal, and viral infection models. BMVs induce protective immunity by promoting both systemic and mucosal immune responses, thereby reducing bacterial burden and limiting pathogen colonization across diverse infection models. These properties have supported their application in viral vaccine development, including influenza and SARS-CoV-2, with the potential to enhance mucosal immunity. Despite these advantages, challenges remain in standardization, safety, and antigen-loading efficiency. Engineered BMVs incorporating protein or mRNA antigens may further enhance antigen presentation and CD8⁺ T cell responses. This review summarizes the biological features, immunological mechanisms, and future potential of BMVs in vaccine development. Full article

This review demonstrates that the diagnostic and prognostic significance of glial fibrillary acidic protein (GFAP) is not limited to its use as a marker of astrocytic damage but should also be considered in the context of the diversity of GFAP isoforms, their heterogeneous tissue-specific expression and their pronounced association with extracellular vesicles (EVs). The data presented in this review indicate that GFAP-positive (GFAP+) EVs possess broad clinical relevance in both acute and chronic pathologies of the nervous system, including ischemic stroke, traumatic brain injury, glioblastoma, and potentially diabetic and drug-induced polyneuropathy. Particular attention is given to the critical analysis of methodological approaches for studying GFAP+ EVs, including discussion of their proposed biogenesis, mechanisms of intravesicular incorporation of cytoskeletal fragments, and the hypothetical sorption of GFAP within the vesicular protein corona. A principal conclusion of this work is that, despite the high translational potential of GFAP+ vesicles as a novel liquid biopsy platform, further implementation of this approach in clinical practice will require standardization of EV isolation protocols, harmonization of phenotyping methodologies in accordance with MISEV 2023 recommendations, and large-scale prospective studies aimed at validating the biological nature, origin, and clinical reproducibility of identified GFAP-associated vesicular subpopulations. Full article

Hyaluronic acid (HA), a native non-sulfated glycosaminoglycan of the extracellular matrix, has emerged as a central biomaterial in tissue engineering due to its biocompatibility, hydration capacity, and receptor-mediated bioactivity. Beyond its structural role, HA actively regulates cellular behaviors through interactions with receptors such as CD44 and RHAMM, with outcomes highly dependent on molecular weight, degradation state, and matrix context. Recent advances in chemical modification and crosslinking strategies have enabled the development of HA-based hydrogels, nanofibers, and composite systems with tunable mechanics and degradation profiles, supporting applications in bone, cartilage, vascular, and skin regeneration, as well as in emerging platforms such as 3D bioprinting and nanomedicine. However, inconsistent biological responses and limited clinical translation remain key challenges. This review integrates current understanding of HA synthesis, physicochemical properties, degradation, and receptor-mediated signaling, and establishes a mechanistic framework linking molecular characteristics, matrix mechanics, and cell responses. Building on this framework, we outline design strategies for multifunctional HA composites, advanced biofabrication approaches, and receptor-targeted systems, providing a basis for the rational engineering of next-generation HA-based biomaterials with improved translational potential. Full article

Unlike newborns, tendon injuries in adults usually lead to fibrotic scarring rather than functional regeneration. This difference is primarily due to the loss of neonatal extracellular matrix (nECM) signaling in adulthood. In this study, we investigated the molecular mechanisms by which a key neonatal ECM proteoglycan, biglycan (Bgn), orchestrates the behavior of tendon stem/progenitor cells (TSPCs) within a scaffold-free 3D cell sheet microenvironment that recapitulates native tendon architecture. Through immunofluorescence screening, we confirmed that Bgn is the predominant proteoglycan in neonatal rat Achilles tendons. Functional validation showed that adding Bgn to cell sheet cultures promoted TSPCs proliferation, maintained stem cell properties, induced tendon differentiation, and encouraged anisotropic alignment—effects similar to those of intact neonatal ECM. Immunodepletion experiments confirmed the causal role of Bgn. Notably, transplanting Bgn-conditioned TSPCs sheets into a rat full-thickness Achilles tendon defect model significantly restored final tensile load, collagen maturation, and gait function. These outcomes were statistically indistinguishable from those of the uninjured contralateral limb. These findings confirm that Bgn-functionalized cell sheet therapy is a viable translational strategy that can effectively recreate a natural 3D regenerative microenvironment. This work sheds light on the mechanisms involved in the determination of stem cell fate by the ECM and establishes Bgn-functionalized cell sheet therapy as a translatable, scaffold-free strategy for overcoming fibrotic repair and restoring functional tendon architecture. Full article

Background: In this study, we radiologically assessed potential increases in microvascularity, extracellular matrix-related changes, and tissue viscoelasticity following carboxytherapy for periorbital hyperpigmentation (POH). We also analyzed the correlation between radiological changes and clinical outcomes and explored implications for future outpatient selection, as well as the potential to predict treatment success based on radiological–clinical correlations. Materials and Methods: The present study included 78 patients (76 women and 2 men) aged over 18 years with Fitzpatrick skin types I–V and moderate-to-severe infraorbital dark circles who applied for treatment at the Dermatology Department in the Cosmetology Unit of Cerrahpaşa Medical Faculty Hospital. Each patient was given manual, pressure-controlled injections of sterile CO₂ into the upper and lower eyelids for 7 weeks, with one round of treatment per week. We conducted dermatoclinical and radiological evaluations, including measurements of epidermis–dermis thickness and SWE, musculus orbicularis oculi pars pretarsalis thickness, and cSMI vascular index percentage, as well as SOOF tissue SWE (measured in kPa). These analyses were performed on both lower eyelids before treatment and at 1 month and 6 months after treatment. Results: After treatment, VAS scores improved significantly. Grayscale ultrasonography showed significant increases in epidermis–dermis and orbicularis oculi thickness at 1 and 6 months (p < 0.05). SMI presented a significant increase in vascular index at both follow-ups (p < 0.05). SOOF SWE values increased significantly at 1 and 6 months, whereas epidermis–dermis SWE did not. Procedural pain was common, and 25 participants withdrew during the 7-week period due to discomfort. Injection depth was not confirmed by real-time imaging, and adverse events were not graded using a standardized classification system. Therefore, tolerability and procedural safety should be interpreted with caution. Conclusions: Carboxytherapy was associated with improvements in clinical outcomes and radiological parameters among patients who were able to tolerate the procedure, including increased microvascularity on SMI and changes suggestive of extracellular matrix-related alterations. These improvements were maintained at the 6-month follow-up, indicating temporal persistence of the observed findings. However, due to the absence of a control group, the results should be interpreted with caution, and further randomized controlled studies are required to confirm these findings and establish causality. Full article

Phosphate (Pi) and calcium (Ca²⁺) are essential mineral ions that play coordinated roles in maintaining normal cellular functions. While various steps of calcium signaling are well characterized, emerging evidence suggests the critical role of both intracellular and extra cellular phosphate in regulating intracellular Ca²⁺. In the cytoplasm, phosphate influences ATP production and organelle calcium buffering and influences the activity of calcium pumps, such as sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase (SERCA) and the plasma membrane Ca²⁺-ATPase (PMCA). Extracellular phosphate, taken up via sodium-dependent phosphate transporters, triggers signaling cascades that affect the processes of calcium influx, storage, and release. Additionally, high extracellular phosphate levels can disrupt calcium homeostasis through the systemic interactions of hormones such as fibroblast growth factor 23 (FGF23), vitamin D and parathyroid hormone (PTH), especially under pathological conditions such as chronic kidney disease (CKD). This article briefly summarizes the current understanding of the bidirectional influence of intra- and extracellular phosphate on calcium dynamics at the cellular level, with a focus on the underlying mechanisms. Full article