Search Results (1,570)

The unfolded protein response (UPR) is a highly conserved adaptive mechanism that restores endoplasmic reticulum (ER) homeostasis under stress. Beyond its canonical roles in proteostasis, the UPR has emerged as a central regulator of immune responses across diverse contexts, including infection, inflammation, cancer, and autoimmunity. IRE1α, PERK, and ATF6 are three principal UPR sensors that coordinate complex signaling networks to regulate antigen presentation, cytokine production, and immune cell differentiation. This review highlights the molecular mechanisms by which small molecules target the UPR to modulate immune responses. In addition, we highlight stress granules (SGs) and the prevalence of protein–protein interactions mediated by intrinsically low-complexity domains (LCDs) in the UPR as potential new avenues for immune modulation. Finally, we discuss future directions for leveraging UPR modulation in immunotherapy, infectious disease, and chronic inflammatory disorders. Full article

Despite significant advances in neurosurgical and critical care, traumatic brain injury (TBI) remains a major cause of morbidity and mortality. Surgical treatment of intracranial hemorrhagic lesions can only target the primary mechanical injuries and their immediate consequences but fails to address the biochemical pathological cascade that unfolds during the second injury. This review synthesizes current knowledge regarding the use of several biomarkers in diagnosis and prognosis assessment. A structured literature search was conducted by querying the PubMed database. Articles evaluating diagnostic and prognostic biomarkers in adult TBI were screened according to Prisma guidelines, and data regarding biomarkers type, cut-off values, and correlations with the outcome were extracted and summarized. Among Central Nervous System (CNS)-Specific markers, S100 calcium-binding protein (S100B) emerged as a remarkably strong negative predictor for Computed Tomography (CT)-visible intracranial lesions (NPV = 97.3–100%), whereas glial fibrillary acidic protein (GFAP) yielded both high NPV and brain specificity. Coagulation parameters such as the international normalized ratio (INR) and fibrinogen were independently correlated with mortality and unfavorable outcomes. Fibrinogen displayed a bidirectional relationship with increased mortality risk at both low (<2 g/L) and high (>4.5 g/L) values. In conclusion, biomarkers quantify the otherwise invisible progression of secondary traumatic brain injury that persists even after successful surgery. Full article

Pollen allergy represents a growing public health concern, yet the role of microplastic pollution in modulating allergen behavior remains largely unresolved. In this study, we investigated interactions between polyethylene terephthalate (PET) microplastics (0.2–12 µm; predominantly 0.4–1 µm) and cedar pollen proteins, with emphasis on the major allergen Cry j 1. Surface charge characterization using the pH drift method revealed two apparent points of zero charge in the acidic (pH 3.0–3.8) and near-neutral (~7.5) regions, indicating surface chemical heterogeneity. Protein adsorption experiments conducted at physiological pH (7.4) showed concentration-dependent and saturable removal of proteins from solution with increasing PET mass and a 3.10-fold preferential enrichment of aromatic-rich protein fractions. Spectroscopic analyses revealed adsorption-induced but non-denaturing structural perturbations, including increased exposure of aromatic residues and partial β-sheet destabilization. Complementary all-atom molecular dynamics simulations showed rapid and stable Cry j 1 adsorption onto PET, anisotropic surface accommodation, modest increases in solvent accessibility, and subtle secondary structure rearrangements without global unfolding. Together, these findings indicate that PET microplastics can selectively bind and structurally modulate pollen allergens in ways that may influence allergen persistence and epitope presentation, with potential implications for IgE-mediated sensitization in polluted environments. Full article

Polyglutamine expansion in Ataxin-2 (ATXN2) is responsible for rare, dominantly inherited Spinocerebellar Ataxia type 2 (SCA2). Together with its paralog Ataxin-2-like (ATXN2L), both proteins have received much interest, since the deletion of their yeast and fly orthologs alleviates TDP-43-triggered neurotoxicity in Amyotrophic Lateral Sclerosis models. Their typical structure across evolution combines LSm with LSm-Associated Domains and a PAM2 motif. To understand the physiological regulation and functions of Ataxin-2 homologs, the phylogenesis of sequences was analyzed. Human ATXN2 harbors multiple alternative start codons, e.g., from an intrinsically disordered sequence (IDR) present since armadillo, or from the polyQ sequence that arose since amphibians, or from the LSm domain since primitive eukaryotes. Multiple smaller isoforms also exist across the C-terminus. Therapeutic knockdown of polyQ expansions in human ATXN2 should selectively target exon 1B. PolyQ repeats developed repeatedly, usually framed and often interrupted by (poly)Pro, originally near PAM2. The LSmAD sequence appeared in algae as the characteristic Ataxin-2 feature with strong conservation. Frequently, Ataxin-2 has added domains, likely due to transcriptional readthrough of neighbor genes during cell stress. These chimerisms show enrichment of rRNA processing; nutrient store mobilization; membrane strengthening via lipid, protein, and glycosylated components; and cell protrusions. Thus, any mutation of Ataxin-2 has complex effects, also affecting membrane resilience. Full article

Background: Aneurysmal subarachnoid hemorrhage (aSAH) induces complex systemic inflammatory and metabolic responses that may influence clinical outcome. DSC provides an integrative biophysical readout of proteome-level thermodynamic behavior rather than protein-specific identification or quantification; however, its applicability in neurocritical conditions remains largely unexplored. This pilot study aimed to explore whether serum DSC profiles show preliminary associations with clinical severity and neurological outcomes after aSAH. Methods: Serum samples collected on day 1 after aSAH were analyzed by DSC and compared with healthy control samples. A small patient cohort was stratified according to clinical severity and neurological outcome. Thermograms were evaluated based on melting temperatures (Tm), calorimetric enthalpy (ΔHcal), heat capacity changes (ΔCp), and the relative contributions of major serum protein components. Results: Healthy controls exhibited characteristic DSC profiles dominated by a cooperative albumin transition at approximately 65–66 °C. In this limited cohort, patients with severe clinical conditions and unfavorable outcomes displayed marked thermogram reorganization, including increased albumin Tm, reduced unfolding cooperativity, decreased ΔCp, and enhanced high-temperature immunoglobulin-related contributions. Patients with mild condition and favorable outcome showed profiles more similar to those of the controls. Notably, patients with severe conditions but favorable outcomes demonstrated heterogeneous albumin-related thermal domains, which may reflect individual-level variability and suggesting dynamic proteomic heterogeneity at the early post-ictus phase. Given the small group sizes, these patterns should be interpreted as exploratory and hypothesis-generating. Conclusions: This pilot exploratory study suggests that serum DSC may capture preliminary thermoanalytical patterns associated with clinical outcomes after aSAH. While the findings indicate the potential of DSC as a systems-level tool in neurocritical care, larger, well-powered studies are required to validate these observations and assess their robustness and generalizability. Full article

Background/Objectives: Doxorubicin (DOX) is an effective chemotherapeutic agent whose clinical utility is limited by cardiotoxicity. To investigate underlying mechanisms, we employed a multi-omics approach integrating transcriptomics and proteomics, leveraging established mouse models of chronic DOX-induced cardiotoxicity. Methods: Five-week-old male mice received weekly DOX (4 mg/kg) or saline injections for six weeks, with heart tissues harvested 4 days post-treatment. Differentially expressed genes (DEGs) and proteins (DEPs) were identified by bulk RNA-seq and proteomics, validated via qPCR and Western blot, respectively. Key DEPs were validated in plasma samples from DOX-treated breast cancer patients. Additionally, temporal comparison was conducted between DEPs in the mice hearts 4 days and 6 weeks post-DOX. Results: RNA-seq revealed upregulation of stress-responsive genes (Phlda3, Trp53inp1) and circadian regulators (Nr1d1), with downregulation of Apelin and Cd74. Proteomics identified upregulation of serpina3n, thrombospondin-1, and epoxide hydrolase 1. Plasma SERPINA3 concentrations were significantly elevated in breast cancer patients 24 h post-DOX. Gene set enrichment analysis (GSEA) revealed upregulated pathways, including p53 signaling, apoptosis, and unfolded protein response. Integrated omics analysis revealed 2089 gene–protein pairs. GSEA of concordant gene–protein pairs implicated p53 signaling, apoptosis, and epithelial–mesenchymal transition in upregulated pathways, while oxidative phosphorylation and metabolic pathways were downregulated. Temporal comparison with a delayed timepoint (6 weeks post-DOX) uncovered dynamic remodeling of cardiac signaling, with early response dominated by inflammatory and apoptotic responses, and delayed response marked by cell cycle and DNA repair pathway activation. Conclusions: This integrated omics study reveals key molecular pathways and temporal changes in DOX-induced cardiotoxicity, identifying potential biomarkers for future cardioprotective strategies. Full article

Sympathetic nervous system (SNS) imbalance is a common pathological basis for cardiovascular diseases, non-alcoholic fatty liver disease, and diabetes. This review focuses on these diseases, analyzing two core mechanisms: excessive sympathetic excitation induced by endoplasmic reticulum stress (ERS) or autophagy dysfunction in key central nuclei (e.g., hypothalamus, rostral ventrolateral medulla); and ERS/autophagy abnormalities in peripheral target organs caused by chronic SNS overactivation. Existing studies confirm that chronic SNS overactivation promotes peripheral metabolic overload via sustained catecholamine release, inducing persistent ERS and disrupting the protective unfolded protein response (UPR)–autophagy network, ultimately leading to cell apoptosis, inflammation, and fibrosis. Notably, central ERS or autophagy dysfunction further perturbs autonomic homeostasis, exacerbating sympathetic overexcitation. This review systematically elaborates on SNS overactivation as a critical bridge mediating UPR–autophagy network dysregulation in central and peripheral tissues, and explores therapeutic prospects of targeting key nodes (e.g., chemical chaperones, specific UPR modulators, nanomedicine), providing a theoretical basis for basic research and clinical translation. Full article

The neonatal heart possesses a unique capacity for reparative healing after myocardial injury, unlike the adult heart. While immune cells, particularly T cells, regulate post-infarction inflammation, their role in age-dependent cardiac repair remains unclear. This study aimed to characterize the temporal activation of T cell subsets and their contribution to immune homeostasis and myocardial repair. Myocardial infarction was induced in mice of different ages, and T cell subsets (CD4+ T cells, CD8+ T cells, and CD4+Foxp3+ T [T-reg] cells) were analyzed using flow cytometry and RNA sequencing. Neonatal hearts exhibited CD4+ T cells, CD8+ T cells, and T-reg cells that gradually increased until seven days post-injury. Transcriptome analysis identified Rcn3 as a neonatal-specific, injury-responsive gene in T-reg cells, with minimal induction in adult and aged hearts, promoting a reparative microenvironment and exerting anti-fibrotic effects via the PI3K/Akt pathway. Under endoplasmic reticulum stress, Rcn3 activated unfolded protein response genes, and Rcn3-conditioned media reduced fibrosis-associated gene expression in adult cardiac fibroblasts. In a conditional knockout mouse model (Lck-cre; Rcn3^fl/fl), Rcn3 deletion in T cells led to impaired cardiac function recovery and increased fibrosis post-injury. These findings suggest that neonatal T-reg cells play a crucial role in cardiac repair, with Rcn3 as a potential therapeutic target for enhancing immune-mediated cardiac repair and limiting pathological remodeling in the adult heart. Full article

Pea albumin is a high-quality plant-based protein with growing relevance in food applications, yet the effects of pH and thermal treatment on its structural and functional properties remain insufficiently understood. This study investigated the effects of environmental factors, namely pH (3, 5, 7, 9) and temperature (40, 60, 80, 100 °C), on the structural behavior and functionality of pea albumin. Structural changes were characterized through particle size, Zeta potential, surface hydrophobicity, and intrinsic fluorescence. Functional properties, including solubility, foaming ability, and emulsifying capacity, were evaluated and compared with untreated controls. Under alkaline conditions (pH 9), stronger electrostatic repulsion led to a 29.5% reduction in particle size, a 76.47% increase in Zeta potential, enhanced protein unfolding, and a 19.06% increase in surface hydrophobicity. At this pH, solubility increased by 24.8%, accompanied by notable improvements in foaming and emulsifying performance. Moderate heating (40, 60 °C) induced partial unfolding, resulting in decreased particle size and enhanced solubility, which further contributed to improved functional behavior. Pearson correlation analysis demonstrated significant associations between structural indicators (particle size, Zeta potential, surface hydrophobicity) and functional properties, highlighting the structure–function relationship of pea albumin. This work provides a comprehensive understanding of environmental factor-induced changes in pea albumin and offers valuable insights for its optimized application in plant-based foods. Full article

Nanoparticles interact dynamically with proteins, often leading to adsorption-induced conformational changes that alter protein function and contribute to corona formation. Here we investigated the adsorption and unfolding of a model protein GB1 on latex nanoparticle surfaces using a combination of mutational analysis, equilibrium binding assays, stopped-flow kinetics and Φ-value interpretation. Seven site-directed variants of GB1 were studied to dissect residue-specific contributions to adsorption energetics. Fluorescence binding isotherms revealed that D46A and T53A mutations weakened surface affinity, while kinetic analysis demonstrated that D46A reduced adsorption rate by ~6-fold and produced a dramatic unfolding/refolding shift, identifying Asp46 as a key docking site. Φ-value analysis further highlighted Asp46 and Thr53 as central residues in the adsorption transition state, whereas mutations in the hydrophobic core or distal loops had negligible effects. These results support a dock–loosen–unfold mechanism in which electrostatic recognition initiates binding, followed by hydrophobic exposure and hairpin stabilization. This residue-level sampling of key sites advances mechanistic understanding of protein–nanoparticle interactions and suggests strategies for tuning surface charge to control corona formation. Our approach provides a generalizable method to map adsorption transition states, with implications for designing safer nanomaterials, predicting protein corona composition, and harnessing protein unfolding in biosensing applications. Full article

Metal nanoparticles (NP) are increasingly used in biomedical applications. Among them, silver NPs (AgNPs) are used as active components in antibacterial coatings for wound dressings, medical devices, implants, cosmetics, textiles, and food packaging. On the other hand, AgNPs can be toxic to humans, depending on the dose and route of exposure, as agents delivering silver to cells. The cysteine residues are the primary molecular targets in such exposures, due to the high affinity of Ag⁺ ions to thiol groups. The Endothelial monocyte-activating polypeptide II (EMAP II), a cleaved C-terminal peptide of the intracellular aminoacyl-tRNA synthetase multifunctional protein AIMP1, contains five cysteines exposed at its surface. This prompted the question of whether they can be targeted by Ag⁺ ions present at the AgNPs surface or released from AgNPs in the course of oxidative metabolism of the cell. We explored the interactions between recombinant EMAP II, tRNA, and AgNPs using UV-Vis and fluorescence spectroscopy, providing insight into the effects of AgNPs dissolution kinetics on interaction EMAP II with tRNA. In addition, the EMAP II fragments binding to intact AgNPs were established by heteronuclear ¹H-¹⁵N HSQC spectra utilizing a paramagnetic probe. Structural analysis of the EMAP II reveal that the 3D structure of protein was destabilized (partially denatured) by the binding of Ag⁺ ions released from AgNPs at the most exposed cysteines. Surprisingly, this effect enhanced tRNA affinity to EMAP II, lowering its $K_d$. The course of the EMAP II/tRNA/AgNP reaction was also modulated by other factors, such as the presence of Mg²⁺ ions and TCEP, a thiol-group protector used to mimic the reducing conditions of the cell. Full article

Fermentation is an effective method to enhance the bioactivity of plant proteins, yet the link between the functionality and conformational state of fermented soybean 11S protein (F11S) requires clarification. This study first evaluated the antioxidative efficacy of F11S and its application in emulsion systems, followed by a mechanistic investigation into its structural evolution. Results showed that the bioactivity of F11S was strictly fermentation-time-dependent, reaching its peak at 16 h. At this stage, F11S exhibited maximal scavenging capacities for ·OH (84.51 ± 2.53%) and DPPH radicals (93.84 ± 2.62%). Crucially, in a Tween 20 emulsion system, the F11S-16h fraction demonstrated superior oxidative stability, maintaining the lowest peroxide value (4.33 ± 0.53 mmol/kg) after 15 days of storage. To elucidate the mechanism behind this enhanced functionality, structural analysis was conducted. It revealed that while surface hydrophobicity peaked at 12 h due to protein unfolding, extended fermentation to 16 h induced a refolding process, guiding the protein into a thermodynamically stable conformation. These findings indicate that the stable refolded structure formed at 16 h, rather than maximal hydrophobicity, is the key determinant for the superior antioxidant performance and emulsion stabilizing ability of F11S. Full article

Neurodegenerative diseases such as Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis, and Huntington’s disease represent a major challenge in neuroscience due to their complex, multifactorial nature and the absence of curative treatments. These disorders share common molecular mechanisms, including oxidative stress, mitochondrial dysfunction, proteostasis collapse, calcium dyshomeostasis, chronic neuroinflammation, and the prion-like propagation of misfolded proteins. Together, these processes trigger a cascade of cellular damage that culminates in synaptic dysfunction and programmed neuronal death. This review integrates current evidence on the sequential stages of neurodegeneration, emphasizing the convergence of oxidative, inflammatory, and proteotoxic pathways that drive neuronal vulnerability. Moreover, it explores emerging therapeutic strategies aimed at restoring cellular homeostasis, such as Nrf2 activation, modulation of the unfolded protein response (UPR), enhancement of autophagy, immunotherapy against pathological proteins, and gene therapy approaches. The dynamic interplay among mitochondria, endoplasmic reticulum, and glial cells is highlighted as a central element in disease progression. Understanding these interconnected mechanisms provides a foundation for developing multi-targeted interventions capable of halting or delaying neuronal loss and improving clinical outcomes in neurodegenerative disorders. This work provides an integrative and introductory overview of the convergent mechanisms underlying neurodegeneration rather than an exhaustive mechanistic analysis. Full article

Mitochondrial dysfunction represents a central hallmark of aging and a broad spectrum of chronic diseases, ranging from metabolic to neurodegenerative and ocular disorders. Nicotinamide riboside (NR), a vitamin B₃ derivative and efficient precursor of NAD⁺ (nicotinamide adenine dinucleotide), and berberine (BBR), an isoquinoline alkaloid widely investigated in metabolic regulation, have independently emerged as promising mitochondrial modulators. NR enhances cellular NAD⁺ pools, thereby activating sirtuin-dependent pathways, stimulating PGC-1α–mediated mitochondrial biogenesis, and triggering the mitochondrial unfolded protein response (UPR^mt). BBR, by contrast, primarily activates AMPK (AMP-activated protein kinase) and interacts with respiratory complex I, improving bioenergetics, reducing mitochondrial reactive oxygen species, and promoting mitophagy and organelle quality control. Importantly, despite distinct upstream mechanisms, NR and BBR converge on shared signaling pathways that support mitochondrial health, including redox balance, metabolic flexibility, and immunometabolic regulation. Unlike previous reviews addressing these compounds separately, this article integrates current preclinical and clinical findings to provide a unified perspective on their converging actions. We critically discuss translational opportunities as well as limitations, including heterogeneous clinical outcomes and the need for robust biomarkers of mitochondrial function. By outlining overlapping and complementary mechanisms, we highlight NR and BBR as rational combinatorial strategies to restore mitochondrial resilience. This integrative perspective may guide the design of next-generation clinical trials and advance precision approaches in mitochondrial medicine. Full article

Necrosis is a characteristic feature of glioblastoma multiforme (GBM) and is closely associated with tumor-associated inflammation and poor clinical outcomes. However, the molecular consequences of necrotic cell death on endoplasmic reticulum (ER) stress signaling in GBM cells remain unclear. In this study, we examined the effects of necrotic cells on the ER stress signaling and unfolded protein response (UPR) in human glioblastoma cell lines. Exposure to necrotic cells reduced IRE1α phosphorylation and increased unspliced XBP1 (XBP1u) accumulation, without affecting PERK or ATF6 pathways. These changes were accompanied by enhanced IκBα phosphorylation and impaired autophagic degradation. Treatment with ER stress inducers failed to reverse XBP1u accumulation, and reduced phosphorylation of PKAc was observed together with decreased IRE1α activation. Transcriptomic analysis and quantitative reverse transcription PCR (qRT-PCR) revealed that necrotic cell-induced XBP1u was associated with altered expression of XBP1-related genes, while XBP1 knockdown produced similar transcriptional changes and enhanced the effects of necrotic cell treatment. These findings suggest that necrotic cells impair canonical IRE1α-XBP1 signaling and induce transcriptional reprogramming in glioblastoma cells, which may contribute to tumor progression. Full article