Search Results (154)

Background/Objectives: Extracellular matrix remodeling, cellular stress responses, and blood–brain/blood–tumor barrier-related alterations are important processes involved in brain tumor biology. This exploratory cross-sectional pilot study evaluated circulating circulating protein disulfide isomerase A4 (PDIA4), matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and claudin-2 (CLDN2) concentrations in vitamin D-deficient patients with different brain tumor entities and aimed to provide preliminary effect-size estimates for future studies. Methods: A total of 62 vitamin D-deficient participants were included, comprising patients with glioblastoma (GBM; n = 15), brain metastases (n = 20), and meningioma (n = 8) and surgical controls with degenerative spine disease (n = 19). Serum biomarker concentrations were measured using enzyme-linked immunosorbent assays. Global between-group effect sizes were estimated using η², while exploratory pairwise comparisons and associations with tumor size were assessed using non-parametric methods. Effect-size estimates were prioritized, with p-values reported to provide complementary inferential context. Results: The largest global between-group effect-sizes were observed for CLDN2 (η² = 0.35) and MMP-2 (η² = 0.22), whereas the estimated effects were small for MMP-9 (η² = 0.05) and negligible for PDIA4 (η² = 0.00). Exploratory pairwise comparisons indicated lower serum MMP-2 concentrations in patients with GBM than in surgical controls and lower CLDN2 concentrations in patients with GBM and brain metastases than in controls. Positive exploratory associations were observed between tumor size and PDIA4 concentration in the GBM group (Spearman’s rho = 0.56; 95% CI: 0.02–0.90) and between tumor size and MMP-2 concentration in patients with brain metastases (rho = 0.46; 95% CI: 0.01–0.90). Conclusions: These preliminary effect-size estimates, together with the exploratory correlations with tumor size, may inform biomarker selection and sample-size planning in future prospective studies. The findings should not be interpreted as robust diagnostic or prognostic evidence and require validation in larger, independent, and well-controlled cohorts. Full article

Heat stress causes severe oxidative damage and immune cell death in marine bivalves, but its upstream regulators remain unclear. This study identified regulators linking heat stress to oxidative damage in Pacific oyster haemocytes. Under 30 °C exposure, the apoptosis rate of oyster haemocytes increased from ~4.54% to 17.40% at 24 h, accompanied by elevated ROS, malondialdehyde, and lipid hydroperoxide and reduced SOD activity. GSEA and protein interaction analysis of the haemocyte transcriptome pinpointed protein disulfide isomerase A6 (CgPDIA6) as the hub gene linking endoplasmic reticulum stress, apoptosis, and oxidative stress. Single-cell in silico knockout placed CgPDIA6 at the head of a coupled SOD–peroxiredoxin relay (CgSOD1, CgSOD2, CgPRDX6) and shifted haemocytes toward a stress-activated state. This prediction was confirmed by RNAi knockdown, in which silencing CgPDIA6 aggravated heat-induced oxidative injury, reduced the expression of antioxidant-related genes (CgSOD1, CgSOD2, and CgPRDX6), and further suppressed SOD activity. Molecular dynamics simulations showed that heat destabilized its catalytic thioredoxin domains, compromising its protective function. These results demonstrate that CgPDIA6 protects haemocytes against heat-induced oxidative damage by sustaining antioxidant enzyme activity, providing insights into redox regulation and heat adaptation in mollusks. Full article

Gestational diabetes mellitus (GDM) is increasingly recognized as a complex pathology rooted in systemic and organelle-level dysfunction, specifically involving chronic low-grade inflammation (CLGI), mitochondrial impairment, and endoplasmic reticulum (ER) stress. Central to this pathophysiology is mitochondrial dysfunction, characterized by reduced respiration, impaired metabolic flexibility, and dysregulated fission/fusion machinery, which fuels a self-perpetuating cycle of reactive oxygen species (ROS) production. Concurrently, chronic ER stress triggered by hyperglycemia and lipotoxicity activates the unfolded protein response (UPR), further amplifying redox imbalance through the Endoplasmic Reticulum Oxidoreductin 1/Protein Disulfide Isomerase (ERO1/PDI) axis and bridging metabolic toxicity to inflammation via c-Jun N-terminal kinase (JNK) and nuclear factor kappa-light-chain–enhancer of activated B cells (NF-κB) signaling. The Advanced Glycation Endproducts (AGEs) and the Receptor for Advanced Glycation Endproducts (RAGE) axis act as a molecular catalyst that sequester antioxidants and drive pro-inflammatory feedback loops. These converging mechanisms culminate in profound placental maladaptation, including structural abnormalities like chorangiosis and functional defects in nutrient transport mediated by hyperactive mechanistic target of rapamycin complex 1 (mTORC1) signaling. This review article provides insight into recent evidence to elucidate the meta-inflammatory environment of GDM, where modest but sustained elevations in biomarkers like Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) disrupt redox homeostasis and impair insulin signaling pathways through the activation of stress-sensitive kinases. By integrating these molecular perspectives, the article underscores the necessity of targeting the systemic inflammatory and oxidative continuum spanning pre-conception to the antenatal period through lifestyle interventions and emerging therapeutic strategies to mitigate GDM risk and improve maternal–fetal outcomes. Full article

Antiretroviral therapy (ART) effectively controls Human Immunodeficiency Virus Type-1 (HIV-1) infection in people with HIV-1 (PWH), preventing the progression of their infections to AIDS. However, as PWH age, they experience lifestyle- and age-related diseases, notably various types of cancer beyond those traditionally associated with AIDS, with greater incidence and mortality than their non-HIV-1-positive counterparts, despite effective arrest of HIV-1 infection by ART. Dysregulation of redox enzymes presents an underexplored linkage between HIV-1 infection and cancer comorbidity, impacting reactive oxygen/nitrogen species (RONS) management, inflammation, immune function, and mitochondrial function. Chronic HIV-1 infection increases both RONS production and RONS neutralization responses, accelerating development of a sustained RONS-rich environment that still possesses sufficient dampening to prevent outright cytotoxic effects. Such an environment promotes both tumor proliferation and resistance adaptations to chemo- and radiotherapies. This review considers the effects of chronic HIV-1 infection on redox enzyme function and links these effects to tumorigenic mechanisms as potentially shared pathways. We then examine current methods of modulating redox function, consider how these could potentially impact both HIV-1 infection and cancer progression, and lastly propose future methods of co-treatment that could be explored. Full article

The vitamin D receptor (VDR) acts as both a nuclear transcription factor and a non-genomic mediator that regulates a broad spectrum of physiological processes beyond calcium and phosphate homeostasis. VDR plays an important role in the modulation of ion channels across multiple tissues, including osteoblasts, renal and intestinal epithelial cells, neurons, and vascular smooth muscle. These regulatory mechanisms encompass genomic actions through vitamin D response elements in target genes—such as TRPV5, TRPV6, KCNK3, and KCNH1—as well as rapid, non-genomic actions at the plasma membrane involving protein disulfide isomerase A3 and associated signaling cascades. VDR-mediated transcriptional control of calcium, potassium, and chloride channels contributes to the fine-tuning of cellular excitability, calcium transport, and mitochondrial function. Evidence also implicates VDR–ion channel crosstalk in various pathological contexts, including renal cell carcinoma, breast and cervical cancers, pulmonary arterial hypertension, and osteoporosis. Understanding the molecular interplay between VDR and ion channels provides new perspectives on the pleiotropic effects of vitamin D and offers promising therapeutic opportunities in oncology, cardiovascular disease, and skeletal disorders. This review synthesizes previous and current evidence on the genomic and non-genomic mechanisms underlying VDR–ion channel regulation and highlights novel frontiers in vitamin D signaling relevant to human health and disease. Full article

The endoplasmic reticulum (ER) is critical in aiding cells in ensuring that proteins are folded and processed correctly, particularly during stressful situations. ER oxidoreductin-1 alpha (ERO1α) is an enzyme that is responsible for the formation of disulfide bonds during protein folding, along with protein disulfide isomerase (PDI). This redox pathway is often highly upregulated in cancer cells, allowing tumors to survive harsh conditions such as hypoxia and nutrient deprivation. This review discusses the role of the ERO1α–PDI system in cancer development through the regulation of oxidative stress, redox homeostasis, and tumor plasticity. It further shows the therapeutic potential of interrupting the ERO1α–PDI axis, which could lead to protein misfolding; enhanced generation of reactive oxygen species (ROS); and, eventually, cancer cell death. Full article

Quiescin sulfhydryl oxidase 1 (QSOX1) is a disulfide bond-forming enzyme with both disulfide isomerase and oxidoreductase activities. It plays an important role in protein folding, stability, and secretion. Growing evidence demonstrates that QSOX1 is upregulated in multiple cancer types and influences key behaviors of cancer cells, including proliferation, migration, invasion, and metastasis. Elevated QSOX1 expression is also associated with tumor malignancy and disease relapse. However, the molecular mechanisms by which QSOX1 drives cancer progression remain incompletely understood. In this review, we summarize current knowledge of QSOX1 expression and regulation in cancer, discuss its functional roles, and highlight key unanswered questions to warrant further investigation. Full article

Thymoquinone (TQ), the main bioactive ingredient of Nigella sativa, exhibits numerous pharmacological activities and is used for the prevention of many diseases including hypertension and cancer. However, information concerning the effects of TQ on platelets is limited. In this study, we used the upgraded laser microparticle analyzer LaSca-TMF for simultaneous analysis of platelet shape change, aggregation, and changes in [Ca²⁺]_i. We showed that TQ acutely inhibited platelet aggregation induced by ADP, Trap-6, and CRP; however, the rise of [Ca²⁺]_i was inhibited only in CRP-stimulated platelets, but not in ADP- or Trap-6-stimulated ones. DTT, a thiol-reducing agent, prevented TQ-induced effects in platelets, indicating that protein disulfide isomerases could be involved in the regulation of TQ effects on platelets. Our results, for the first time, demonstrated acute inhibitory effects of TQ on platelet activation induced by GPCRs and ITAM-containing receptors, which were independent of PKA and caspase-3 activation. To the best of our knowledge, this is the first example in which complete inhibition of ADP- and Trap-6-, but not CRP-induced, aggregation is accompanied by high [Ca²⁺]_i levels. Additional experimental approaches are required to explain some effects of TQ on calcium homeostasis and TQ could be a valuable molecule for the analysis of calcium homeostasis in platelets and other cells. Full article

Heme proteins are central to metabolism and stress responses but remain challenging to express recombinantly due to cytotoxicity and folding constraints. Phytoglobins (Pgbs) exemplify these difficulties, as expression protocols often fail to translate across protein species. Here, we used a cell-free protein synthesis (CFPS) platform powered by digital microfluidics to screen expression determinants for sugar beet Pgb 1.2 (BvPgb 1.2), its C86A variant, and three of eight newly identified oat Pgbs (AsPgbs), including their cysteine-to-alanine substituted variants. Benchmarking with multiple solubility tags and cell-free blends revealed protein- and variant-specific preferences, with alanine substitutions frequently improving expression and purification yields. Oxidative additives such as glutathione disulfide, alone or combined with protein disulfide isomerase, consistently enhanced production, underscoring the importance of redox environments for Pgb stability. Two selected variants were scaled up and yielded putative soluble apo-form proteins. The results highlight how CFPS enables rapid, parallelized identification of expression requirements while uncovering the role of conserved cysteines and redox conditions in Pgb biogenesis. Full article

Hypoxia, oxidative stress, and impaired protein folding contribute to tumor progression and therapy resistance. Endoplasmic Reticulum Oxidoreductin 1 Alpha (ERO1α) is a key enzyme regulating redox homeostasis in the endoplasmic reticulum by reoxidizing protein disulfide isomerase, facilitating disulfide bond formation, and generating reactive oxygen species. Elevated ERO1α levels are associated with increased tumor aggressiveness, metastasis, and poor clinical outcomes. Despite growing evidence of its tumor-promoting functions, no clinically approved ERO1α inhibitors exist. This systematic review provides a comprehensive and integrative analysis of current research on ERO1α in breast cancer, emphasizing its roles in hypoxia response, angiogenesis, immune modulation, and ferroptosis resistance. We discuss mechanistic links, including VEGF-A maturation and PD-L1-mediated immune evasion, and highlight recent advances in small-molecule ERO1α inhibitors and preclinical therapeutic strategies. By consolidating molecular insights and translational considerations, this review underscores ERO1α as both a promising therapeutic target and potential prognostic marker, offering guidance for future drug development and targeted interventions in redox-dependent cancer pathways. Full article

Thiol isomerases are a family of enzymes that participate in oxidative protein folding. They contain highly reactive vicinal thiols in a CXXC motif within their catalytic domains to mediate thiol-disulfide switching as part of their reductase, oxidase, and isomerase activity. In addition, they participate in chaperone function by binding to partially folded or misfolded proteins and preventing aggregation, thereby facilitating correct protein folding. The CXXC motif is conducive to oxidative influence based on the sulfur nucleophilicity. Redox modification of the CXXC motif may influence the enzymatic function. In this review we briefly discuss the family of thiol isomerases as it relates to thrombotic disorders. We then discuss the chemical mechanisms of making and breaking disulfides by the enzymes. Enzymatic and chemical models of oxidizing the CXXC motif are proposed. Lastly, we highlight evidence that natural galloylated polyphenols can inhibit both the coronavirus main protease Mpro and thiol isomerases, supporting a therapeutic strategy for COVID-19-associated coagulopathy and thrombosis by targeting the CXXC motif with these anti-oxidative compounds. Full article

Background: Argas persicus is a hematophagous ectoparasite of poultry and is the vector of several agents infectious to poultry. This study aims to explore the key genes affecting the ovarian development of A. persicus. Methods: RNA-seq was performed on the ovaries of A. persicus before blood-feeding, on the day of engorgement, and 6 days post-engorgement. Utilizing the threshold padj < 0.05 and|log₂(foldchange)| > 1, differentially expressed genes were identified, and hub genes were determined by constructing protein–protein interaction (PPI) networks. Results: A total of 1008 differentially expressed genes were obtained during the feeding period, including 448 up-regulated and 560 down-regulated genes. Further, 2179 differentially expressed genes were screened in the preoviposition stage, including 1957 up-regulated and 222 down-regulated genes. These genes are mainly annotated in functions such as peptidase activity (especially serine protease activity), protein folding, protein assembly, and cell component assembly, and enriched in pathways such as protein processing in endoplasmic reticulum, lysosome, glutathione metabolism, and sphingolipid metabolism. In addition, some proteins that are closely related to ovarian development, including heat shock protein 70, protein disulfide isomerase, paramyosin, troponin I, hexosaminidase, serine protease, Kunitz serine protease inhibitors, and vitellogenin, were obtained. Conclusions: These findings fill the gap in the biological data for the ovarian development of soft ticks, provide a reference database for subsequent proteomics research, and offer fundamental support for the screening and development of candidate antigens for anti-tick vaccines. Full article

Protein Disulfide Isomerases (PDIs) are emerging targets in anticancer therapy, with several PDI inhibitors demonstrating anticancer efficacy in preclinical models. Research has largely focused on “canonical” PDIs, such as PDIA1, which contain CXXC active site motifs where C represents Cysteine. Canonical PDIs have well-studied, critical roles in forming, breaking, and exchanging/scrambling disulfide bonds during protein folding. In contrast, non-canonical PDIs, which harbor CXXS active site motifs, remain less well-studied despite their role as sensors or effectors of protein folding quality control during protein trafficking in the secretory pathway. Here, we provide a review of the literature relating to the non-canonical PDIs ERp44, AGR2, and AGR3, which have been identified as strong dependencies in specific cancer subtypes according to the DepMap database. The biological and biochemical functions of ERp44, AGR2, and AGR3 are discussed, highlighting the role of ERp44 in two mechanisms of protein folding quality control, AGR2 as a selective sensor of mucin protein misfolding, and a unique role for AGR3 in cilia. Finally, we discuss recent efforts to develop small molecule inhibitors of ERp44, AGR2, and AGR3 as tool compounds and experimental therapeutics. Full article

The expression of recombinant proteins in heterologous hosts is a common strategy to obtain larger quantities of the “protein of interest” (POI) for scientific, therapeutic or commercial purposes. However, the experimental success of such an approach critically depends on the choice of an appropriate host system to obtain biologically active forms of the POI. The correct folding of the molecule, mediated by disulfide bond formation, is one of the most critical steps in that process. Here we describe the recombinant expression of hirudin, a leech-derived anticoagulant and thrombin inhibitor, in the yeast Komagataella phaffii (formerly known and mentioned throughout this publication as Pichia pastoris) and in two different strains of Escherichia coli, one of them being especially designed for improved disulfide bond formation through expression of a protein disulfide isomerase. Cultivation of the heterologous hosts and expression of hirudin were performed at different temperatures, ranging from 22 to 42 °C for the bacterial strains and from 20 to 30 °C for the yeast strain, respectively. The thrombin-inhibitory potencies of all hirudin preparations were determined using the thrombin time coagulation assay. To our surprise, the hirudin preparations of P. pastoris were considerably less potent as thrombin inhibitors than the respective preparations of both E. coli strains, indicating that a eukaryotic background is not per se a better choice for the expression of a biologically active eukaryotic protein. The hirudin preparations of both E. coli strains exhibited comparable high thrombin-inhibitory potencies when the strains were cultivated at their respective optimal temperatures, whereas lower or higher cultivation temperatures reduced the inhibitory potencies. Full article

Silkworms synthesize and secrete silk to produce cocoons, which are excellent materials for textile and biomaterial manufacturing applications. However, the gene regulation associated with the post-translational modification of silk proteins remains unknown. In this study, we analyzed the physicochemical properties, evolutionary relationships, and expression patterns of BmPDI in silkworms. Subsequently, we knocked out BmPDI (BmPDI-KO), resulting in significant phenotypes of BmPDI-KO silkworms with smaller silk glands and cocoons, weaker silk mechanical properties, and reduced disulfide bonds in silk-associated proteins. Transcription levels of silk protein-related genes and unfolded protein response signal pathway-related genes were significantly downregulated. In contrast, genes involved in the apoptosis pathway were significantly upregulated in BmPDI-KO silkworms. Knocking out BmPDI in silkworms affected the post-translational modifications of the silk proteins, thereby accumulating misfolded silk proteins and hindering their secretion into the extracellular cells. This further increased endoplasmic reticulum stress, activated the apoptotic pathway, accelerated silk gland cell apoptosis, and significantly reduced the silk yields and mechanical properties of BmPDI-KO silkworm. This study provides a potential exploration of BmPDI in the modification of silk yields and mechanical properties of Bombyx mori. Full article