The glyco-redox interplay: Principles and consequences on the role of reactive oxygen species during protein glycosylation

Exploring Ferroptosis in Allergic Inflammatory Diseases: Emerging Mechanisms and Therapeutic Perspectives

Ferroptosis, a unique form of regulated cell death driven by iron accumulation and lipid peroxidation, has emerged as a critical process in various diseases. Recent evidence suggests its involvement in the pathogenesis of allergic diseases, including asthma, allergic rhinitis, and atopic dermatitis. These conditions are characterized by chronic inflammation, oxidative stress, and immune dysregulation, all of which intersect with the molecular mechanisms of ferroptosis. Key regulators, such as glutathione peroxidase 4 (GPX4), the cystine/glutamate antiporter system Xc-, and iron metabolism pathways, play pivotal roles in ferroptotic processes and their contribution to allergic disease progression. This review explores the mechanistic link between ferroptosis and allergic diseases, emphasizing how oxidative damage and iron overload exacerbate inflammation and tissue injury. We also highlight emerging diagnostic biomarkers, including lipid peroxidation products and iron regulators, which could improve disease monitoring and stratification. Therapeutic strategies targeting ferroptosis, such as GPX4 activators, iron chelators, and lipid peroxidation inhibitors, show promise in preclinical\ studies, offering potential new avenues for treating allergic diseases. However, challenges remain in translating these findings into clinical applications. By integrating current knowledge, this review underscores the need for further research into ferroptosis as both a biomarker and therapeutic target in allergic diseases.

A high-resolution N-glycoproteome landscape of aging mouse ovary

Ovarian aging typically precedes the decline of other organ systems, yet its molecular mechanisms remain poorly understood. Glycosylation as one of the most important protein modifications has been especially unexplored in this context. Here, we present the first high-resolution glycoproteomic landscape of aging mouse ovaries, uncovering site-specific N-glycan signatures across subcellular components such as high proportions of complex glycans, core fucosylation, and LacdiNAc branches at the zone pellucida. We report three major glycosylation alterations in aged ovaries: the frequently changed core-fucosylation associated with cell adhesion and immune responses, the decreased LacdiNAc glycans on zona pellucida (ZP) responsible for fertility decline, and the increased sialylated glycans modified by Neu5Ac and Neu5Gc playing different roles in immune activation and responses. Integrated multi-omic analyses further highlight the unique role of glycosylation, distinct from phosphorylation, in regulating key signaling pathways, antigen processing and presentation, complement coagulation cascades, ROS biosynthetic and metabolic processes, as well as cell death. This study offers a novel glycobiological perspective on ovarian aging, broadening our understanding of its molecular mechanisms beyond traditional multi-omic approaches.

Molecular mechanism of GSH metabolism and autophagy in NAC-promoted recombinant human serum albumin and follicle stimulating hormone beta fusion protein secretion in Pichia pastoris

The Pichia pastoris expression system is a favorable platform for production of pharmaceutical proteins. Treatment of strains with N-acetyl-L-cysteine (NAC) has been shown to enhance the yield of recombinant proteins, thereby contributing to a reduction in production costs. However, the specific mechanism of action of NAC remains unclear. Previous research has indicated that glutathione (GSH) and autophagy are involved in the increased production of human serum albumin and porcine follicle-stimulating hormone β (HSA-pFSHβ) by NAC. This study investigated the potential interaction between GSH and autophagy in the production of HSA-pFSHβ. The findings indicated that sulfhydryl-free antioxidants such as melatonin, vitamin C, or vitamin E did not exhibit similar effects to NAC in enhancing HSA-pFSHβ yield. Moreover, NAC was found to enhance HSA-pFSHβ production by modulating GSH metabolism to reduce GSH consumption, increase total GSH levels, as well as glutathione peroxidase (GSH-Px) and glutathione reductase (GR) activities. Additionally, inhibition of autophagy through disruption of autophagy scaffolding proteins Atg1 or Atg11 led to an increase in recombinant HSA-pFSHβ production. Furthermore, NAC significantly decreased the phosphorylation of Slt2, and the absence of the SLT2 gene influenced the effect of NAC on HSA-pFSHβ secretion by modulating mitophagy and GSH metabolism. In conclusion, these results suggest a complex interplay between GSH metabolism and autophagy in the regulation of NAC-induced HSA-pFSHβ secretion.

Curcumin Attenuates Fumonisin B1-Induced PK-15 Cell Apoptosis by Upregulating miR-1249 Expression to Inhibit the IRE1/MKK7/JNK/CASPASE3 Signaling Pathway

Fumonisin B1 (FB1) is an important toxin which poses global concerns in terms of food safety. Curcumin (Cur), a natural polyphenolic compound, has strong antioxidant and anti-inflammatory effects. Meanwhile, the mechanisms underlying the mitigation of FB1-induced toxicity by Cur are not fully understood, limiting its potential application as a novel feed additive to prevent FB1 toxicity. In this study, porcine kidney cells (PK-15) were used as an experimental model, utilizing mRNA and miRNA transcriptome technologies. The results revealed that Cur upregulated miR-1249 and inhibited the target gene Ern1 in the PK-15 cells, thereby suppressing the IRE1/MKK7/JNK/CASPASE3 endoplasmic reticulum (ER) stress pathway and alleviating FB1-induced cell apoptosis. Cell transfection experiments confirmed that Cur effectively attenuated the apoptosis induced by ER stress following transfection with a miR-1249 inhibitor. Similarly, transfection with a miR-1249 mimic alleviated the ER stress and FB1-induced PK-15 cell apoptosis. These findings reveal that Cur mitigates FB1-induced ER stress and significantly reduces apoptotic damage in porcine kidney cells.

Heat-induced stress modulates cell surface glycans and membrane lipids of coral symbionts

The susceptibility of corals to environmental stress is determined by complex interactions between host genetic variation and the Symbiodiniaceae family community. We exposed genotypes of Montipora capitata hosting primarily Cladocopium or Durusdinium symbionts to ambient conditions and an 8-day heat stress. Symbionts' cell surface glycan composition differed between genera and was significantly affected by temperature and oxidative stress. The metabolic profile of coral holobionts was primarily shaped by symbionts identity, but was also strongly responsive to oxidative stress. At peak temperature stress, betaine lipids in Cladocopium were remodeled to more closely resemble the abundance and saturation state of Durusdinium symbionts, which paralleled a larger metabolic shift in Cladocopium. Exploring how Symbiodiniaceae members regulate stress and host-symbiont affinity helps identify the traits contributing to coral resilience under climate change.

The acetylglucosaminyltransferase GnT-Ⅲ regulates erythroid differentiation through ERK/MAPK signaling

Differentiation therapy is an alternative strategy used in treating chronic myelogenous leukemia to induce the differentiation of immature or cancerous cells toward mature cells and inhibit tumor cell proliferation. We aimed to explore N-glycans' roles in erythroid differentiation using the sodium butyrate (NaBu)-induced model of K562 cells (WT/NaBu cells). Here, using lectin blot, flow cytometry, real-time PCR, and mass spectrometry analyses, we demonstrated that the mRNA levels of N-acetylglucosaminyltransferase Ⅲ ((encoded by the MGAT3 gene) and its product (bisected N-glycans) were significantly increased during erythroid differentiation. To address the importance of GnTN-acetylglucosaminyltransferase-Ⅲ in this progress, we established a stable MGAT3 KO K562 cell line using the CRISPR/Cas9 technology. Compared to WT/NaBu cells, MGAT3 KO significantly impeded the progression of erythroid differentiation, as shown in decreased cell color and levels of erythroid markers, glycophorin A (CD235a), and β-globin. Consistently, MGAT3 KO mitigated the inhibitory impact of NaBu on cell proliferation. During induction, MGAT3 KO suppressed the cellular phosphorylated tyrosine and phospho-extracellular signal-regulated kinase (ERK)1/2 levels. Inhibition of the ERK/mitogen-activated protein kinase signaling pathway using U0126 blocked erythroid differentiation while concurrently suppressing the expression levels of MGAT3 and bisected N-glycans. Furthermore, the lack of bisecting GlcNAc modification on c-Kit and transferrin receptor 1 (CD71) suppressed cellular signaling and accelerated the degradation of the CD71 protein, respectively. Our study highlights the critical role of MGAT3 in regulating erythroid differentiation associated with the ERK/mitogen-activated protein kinase signaling pathway, which may shed light on identifying new differentiation therapy in chronic myelogenous leukemia.

Photo-physical characterizations and evaluation of in-vitro antioxidant, anti-inflammatory and antidiabetic potentials of green synthesized ackee (Blighia sapida) selenium nano-particles

BACKGROUND

Green synthesized nanoparticles have recently gained significant medicinal applications and oftentimes outperform their green sources. Selenium is of fundamental importance to human health, stemming from its distinctive physicochemical properties, such as antioxidant activity, inhibition of Lipid peroxidation, stabilization of membrane proteins, maintenance of membrane fluidity and modulation of cell signaling. Though reports have shown some therapeutic potential of Ackee plant parts such as antioxidant, anti-inflammatory, antimicrobial, neuroprotective, very few scientific proofs still exist in support of these effects.

METHODS

This study synthesized selenium nanoparticles (Se-NPs) from crude methanolic extracts of Ackee leaves (AKL) and Ackee arils (AKA), examined the photo-physical characteristics of the Se-NPs and determined the in-vitro antioxidant, antidiabetic, and anti-inflammatory potentials of AKL, AKA, and their Se-NPs using established protocols.

RESULTS

In both leaves and arils Se-NPs: UV spectroscopy revealed a qualitative absorbance at 310 nm; FTIR indicated multiple vibrations around 4000 cm-1- 400 cm-1; SEM images of 5 µm principally showed consistent size distribution of amorphous and granular shape at a magnification of 10,000X; while EDS spectra strongly confirm the presence of atomic Se compound at 30 kV. Various antioxidant activities assays carried out showed a range of approximately 4 to 60 times higher activities of the AKL, AKA, and Se-NPs than Ascorbic acid-the standard drug used. Furthermore, appreciable activities of more than 50% were obtained for alpha-amylase and alpha-glucosidase inhibitory activities, along with highly significant activities of haemoglobin glycosylation, glucose uptake, membrane stabilization, anti-arthritic, anti-haemolysis activities, when AKL, AKA, and Se-NPs were compared with standard drugs.

CONCLUSION

Encouraging the development and utilization of AKL, AKA, and Se-NPs will provide tremendous therapeutic efficacy and bioavailability approaches towards the management of diabetes, inflammation, and other oxidative stress-related diseases.

Roles of Glyco-Redox in Epithelial Mesenchymal Transition and Mesenchymal Epithelial Transition, Cancer, and Various Diseases

Significance: Reduction-oxidation (redox) regulation is an important biological phenomenon that provides a balance between antioxidants and the generation of reactive oxygen species and reactive nitrogen species under pathophysiological conditions. Structural and functional changes in glycans are also important as post-translational modifications of proteins. The integration of glycobiology and redox biology, called glyco-redox has provided new insights into the mechanisms of epithelial-mesenchymal transition (EMT)/mesenchymal-epithelial transition (MET), cancer, and various diseases including Alzheimer's disease, chronic obstructive lung disease, type 2 diabetes, interstitial pneumonitis, and ulcerative colitis. Recent Advances: Glycans are biosynthesized by specific glycosyltransferases and each glycosyltransferase is either directly or indirectly regulated by oxidative stress and redox regulation. A typical example of glyco-redox is the role of N-glycan referred to as core fucose in superoxide dismutase 3. This glycan was found to be involved in the growth inhibition of cancer cell lines. Critical Issues: The significance of glyco-redox in EMT/MET, cancer, and various diseases was found in major N-glycan branching glycosyltransferases β1,4N-acetylglucosaminyltransferase III, β1,4N-acetylglucosaminyltransferase IV, β1,6N-acetylglucosaminyltransferase V, β1,4-acetylglucosaminyltransfearfse VI, β1,6-acetylglucosaminyltransferase IX, α-1,6 fucosyltransferase, and β-galactoside α-2,6-sialyltransferase 1. Herein, we summarize previous reports on target proteins and how this relates to oxidative stress. We also discuss the products of these processes and their significance to cancer and various diseases. Future Direction: A clear-cut understanding of the significance of glyco-redox in relation to prevention, diagnosis, and therapeutics is required. These studies will open a new road toward glycobiology and redox biology. Antioxid. Redox Signal. 41, 910-926.

Hyperglycosylation as an Indicator of Aging in the Bone Metabolome of Oryzias latipes

Chronological aging of bone tissues is a multi-faceted process that involves a complex interplay of cellular, biochemical, and molecular mechanisms. Metabolites play a crucial role for bone homeostasis, and a changed metabolome is indicative for bone aging, although bone metabolomics are currently understudied. The vertebral bone metabolome of the model fish Japanese medaka (Oryzias latipes) was employed to identify sex-specific markers of bone aging. 265 and 213 metabolites were differently expressed in 8-month-old vs. 3-month-old female and male fish, respectively. The untargeted metabolomics pathway enrichment analysis indicated a sex-independent increased hyperglycosylation in 8-month-old individuals. The upregulated glycosylation pathways included glycosphingolipids, glycosylphosphatidylinositol anchors, O-glycans, and N-glycans. UDP-sugars and sialic acid were found to be major drivers in regulating glycosylation pathways and metabolic flux. The data indicate a disruption of protein processing at the endoplasmic reticulum and changes in O-glycan biosynthesis. Dysregulation of glycosylation, particularly through the hexosamine biosynthetic pathway, may contribute to bone aging and age-related bone loss. The results warrant further investigation into the functional involvement of increased glycosylation in bone aging. The potential of glycan-based biomarkers as early warning systems for bone aging should be explored and would aid in an advanced understanding of the progression of bone diseases such as osteoporosis.

Fundamentals of redox regulation in biology

Oxidation-reduction (redox) reactions are central to the existence of life. Reactive species of oxygen, nitrogen and sulfur mediate redox control of a wide range of essential cellular processes. Yet, excessive levels of oxidants are associated with ageing and many diseases, including cardiological and neurodegenerative diseases, and cancer. Hence, maintaining the fine-tuned steady-state balance of reactive species production and removal is essential. Here, we discuss new insights into the dynamic maintenance of redox homeostasis (that is, redox homeodynamics) and the principles underlying biological redox organization, termed the 'redox code'. We survey how redox changes result in stress responses by hormesis mechanisms, and how the lifelong cumulative exposure to environmental agents, termed the 'exposome', is communicated to cells through redox signals. Better understanding of the molecular and cellular basis of redox biology will guide novel redox medicine approaches aimed at preventing and treating diseases associated with disturbed redox regulation.

Lectin binding to pectoral fin of neonate little skates reared under ambient and projected-end-of-century temperature regimes

The glycosylation of macromolecules can vary both among tissue structural components and by adverse conditions, potentially providing an alternative marker of stress in organisms. Lectins are proteins that bind carbohydrate moieties and lectin histochemistry is a common method to visualize microstructures in biological specimens and diagnose pathophysiological states in human tissues known to alter glycan profiles. However, this technique is not commonly used to assess broad-spectrum changes in cellular glycosylation in response to environmental stressors. In addition, the binding of various lectins has not been studied in elasmobranchs (sharks, skates, and rays). We surveyed the binding tissue structure specificity of 14 plant-derived lectins, using both immunoblotting and immunofluorescence, in the pectoral fins of neonate little skates (Leucoraja erinacea). Skates were reared under present-day or elevated (+5°C above ambient) temperature regimes and evaluated for lectin binding as an indicator of changing cellular glycosylation and tissue structure. Lectin labeling was highly tissue and microstructure specific. Dot blots revealed no significant changes in lectin binding between temperature regimes. In addition, lectins only detected in the elevated temperature treatment were Canavalia ensiformis lectin (Concanavalin A) in spindle cells of muscle and Ricinus communis agglutinin in muscle capillaries. These results provide a reference for lectin labeling in elasmobranch tissue that may aid future investigations.

Altered expression of Sialyl Lewis X in experimental models of Parkinson's disease

The mechanisms underlying neurodegeneration in Parkinson's disease (PD) are still not fully understood. Glycosylation is an important post-translational modification that affects protein function, cell-cell contacts and inflammation and can be modified in pathologic conditions. Although the involvement of aberrant glycosylation has been proposed for PD, the knowledge of the diversity of glycans and their role in PD is still minimal. Sialyl Lewis X (sLeX) is a sialylated and fucosylated tetrasaccharide with essential roles in cell-to-cell recognition processes. Pathological conditions and pro-inflammatory mediators can up-regulate sLeX expression on cell surfaces, which has important consequences in intracellular signalling and immune function. Here, we investigated the expression of this glycan using in vivo and in vitro models of PD. We show the activation of deleterious glycation-related pathways in mouse striatum upon treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a toxin-based model of PD. Importantly, our results show that MPTP triggers the presentation of more proteins decorated with sLeX in mouse cortex and striatum in a time-dependent manner, as well as increased mRNA expression of its rate-limiting enzyme fucosyltransferase 7. sLeX is expressed in neurons, including dopaminergic neurons, and microglia. Although the underlying mechanism that drives increased sLeX epitopes, the nature of the protein scaffolds and their functional importance in PD remain unknown, our data suggest for the first time that sLeX in the brain may have a role in neuronal signalling and immunomodulation in pathological conditions. KEY MESSAGES: MPTP triggers the presentation of proteins decorated with sLeX in mouse brain. MPTP triggers the expression of sLeX rate-limiting enzyme FUT 7 in striatum. sLeX is expressed in neurons, including dopaminergic neurons, and microglia. sLeX in the brain may have a role in neuronal signalling and immunomodulation.

Effect of a Very Low-Calorie Diet on Oxidative Stress, Inflammatory and Metabolomic Profile in Metabolically Healthy and Unhealthy Obese Subjects

The purpose of the study was to determine the impact of weight loss through calorie restriction on metabolic profile, and inflammatory and oxidative stress parameters in metabolically healthy (MHO) and unhealthy (MUHO) obese individuals. A total of 74 subjects (34 MHO and 40 MUHO) received two cycles of a very low-calorie diet, alternating with a hypocaloric diet for 24 weeks. Biochemical, oxidative stress, and inflammatory markers, as well as serum metabolomic analysis by nuclear magnetic resonance, were performed at baseline and at the end of the intervention. After the diet, there was an improvement in insulin resistance, as well as a significant decrease in inflammatory parameters, enhancing oxidative damage, mitochondrial membrane potential, glutathione, and antioxidant capacity. This improvement was more significant in the MUHO group. The metabolomic analysis showed a healthier profile in lipoprotein profile. Lipid carbonyls also decrease at the same time as unsaturated fatty acids increase. We also display a small decrease in succinate, glycA, alanine, and BCAAs (valine and isoleucine), and a slight increase in taurine. These findings show that moderate weight reduction leads to an improvement in lipid profile and subfractions and a reduction in oxidative stress and inflammatory markers; these changes are more pronounced in the MUHO population.

Glycosylation: A new signaling paradigm for the neurovascular diseases

A wide range of life-threatening conditions with complicated pathogenesis involves neurovascular disorders encompassing Neurovascular unit (NVU) damage. The pathophysiology of NVU is characterized by several features including tissue hypoxia, stimulation of inflammatory and angiogenic processes, and the initiation of intricate molecular interactions, collectively leading to an elevation in blood-brain barrier permeability, atherosclerosis and ultimately, neurovascular diseases. The presence of compelling data about the significant involvement of the glycosylation in the development of diseases has sparked a discussion on whether the abnormal glycosylation may serve as a causal factor for neurovascular disorders, rather than being just recruited as a secondary player in regulating the critical events during the development processes like embryo growth and angiogenesis. An essential tool for both developing new anti-ischemic therapies and understanding the processes of ischemic brain damage is undertaking pre-clinical studies of neurovascular disorders. Together with the post-translational modification of proteins, the modulation of glycosylation and its enzymes implicates itself in several abnormal activities which are known to accelerate neuronal vasculopathy. Despite the failure of the majority of glycosylation-based preclinical and clinical studies over the past years, there is a significant probability to provide neuroprotection utilizing modern and advanced approaches to target abnormal glycosylation activity at embryonic stages as well. This article focuses on a variety of experimental evidence to postulate the interconnection between glycosylation and vascular disorders along with possible treatment options.

Melatonin Action in Type 2 Diabetic Parotid Gland and Dental Pulp: In Vitro and Bioinformatic Findings

Type 2 diabetes mellitus (T2DM) is associated with functional deterioration of the salivary gland and dental pulp, related to oxidative stress. The aim was to integrate experimental and bioinformatic findings to analyze the cellular mechanism of melatonin (MEL) action in the human parotid gland and dental pulp in diabetes. Human parotid gland tissue was obtained from 16 non-diabetic and 16 diabetic participants, as well as human dental pulp from 15 non-diabetic and 15 diabetic participants. In human non-diabetic and diabetic parotid gland cells (hPGCs) as well as in dental pulp cells (hDPCs), cultured in hyper- and normoglycemic conditions, glial cell line-derived neurotrophic factor (GDNF), MEL, inducible nitric oxide synthase (iNOS) protein expression, and superoxide dismutase (SOD) activity were measured by enzyme-linked immunosorbent assay (ELISA) and spectrophotometrically. Bioinformatic analysis was performed using ShinyGO (v.0.75) application. Diabetic participants had increased GDNF and decreased MEL in parotid (p < 0.01) and dental pulp (p < 0.05) tissues, associated with increased iNOS and SOD activity. Normoglycemic hDPCs and non-diabetic hPGCs treated with 0.1 mM MEL had increased GDNF (p < 0.05), while hyperglycemic hDPCs treated with 1 mM MEL showed a decrease in up-regulated GDNF (p < 0.05). Enrichment analyses showed interference with stress and ATF/CREB signaling. MEL induced the stress-protective mechanism in hyperglycemic hDPCs and diabetic hPGCs, suggesting MEL could be beneficial for diabetes-associated disturbances in oral tissues.

Metalloglycobiology: The power of metals in regulating glycosylation

The remarkable structural diversity of glycans that is exposed at the cell surface and generated along the secretory pathway is tightly regulated by several factors. The recent identification of human glycosylation diseases related to metal transporter defects opened a completely new field of investigation, referred to herein as "metalloglycobiology", on how metal changes can affect the glycosylation and hence the glycan structures that are produced. Although this field is in its infancy, this review aims to go through the different glycosylation steps/pathways that are metal dependent and that could be impacted by metal homeostasis dysregulations.

Blood Metabolite Profiling of Antarctic Expedition Members: An 1H NMR Spectroscopy-Based Study

Serum samples from eight participants during the XV winter-over at Concordia base (Antarctic expedition) collected at defined time points, including predeparture, constituted the key substrates for a specific metabolomics study. To ascertain acute changes and chronic adaptation to hypoxia, the metabolic profiles of the serum samples were analyzed using NMR spectroscopy, with principal components analysis (PCA) followed by partial least squares and orthogonal partial least squares discriminant analyses (PLS-DA and OPLS-DA) used as supervised classification methods. Multivariate data analyses clearly highlighted an adaptation period characterized by an increase in the levels of circulating glutamine and lipids, mobilized to supply the body energy needs. At the same time, a reduction in the circulating levels of glutamate and N-acetyl glycoproteins, stress condition indicators, and proinflammatory markers were also found in the NMR data investigation. Subsequent pathway analysis showed possible perturbations in metabolic processes, potentially related to the physiological adaptation, predominantly found by comparing the baseline (at sea level, before mission onset), the base arrival, and the mission ending collected values.

Fucosyltransferase 8 (FUT8) and core fucose expression in oxidative stress response

GlycoMaple is a new tool to predict glycan structures based on the expression levels of 950 genes encoding glycan biosynthesis-related enzymes and proteins using RNA-seq data. The antioxidant response, protecting cells from oxidative stress, has been focused on because its activation may relieve pathological conditions, such as neurodegenerative diseases. Genes involved in the antioxidant response are defined within the GO:0006979 category, including 441 human genes. Fifteen genes overlap between the glycan biosynthesis-related genes defined by GlycoMaple and the antioxidant response genes defined by GO:0006979, one of which is FUT8. 5-Hydroxy-4-phenyl-butenolide (5H4PB) extracted from Chinese aromatic vinegar induces the expression of a series of antioxidant response genes that protect cells from oxidative stress via activation of the nuclear factor erythroid 2-related factor 2-antioxidant response element pathway. Here, we show that FUT8 is upregulated in both our RNA-seq data set of 5H4PB-treated cells and publicly available RNA-seq data set of cells treated with another antioxidant, sulforaphane. Applying our RNA-seq data set to GlycoMaple led to a prediction of an increase in the core fucose of N-glycan that was confirmed by flow cytometry using a fucose-binding lectin. These results suggest that FUT8 and core fucose expression may increase upon the antioxidant response.

Comparative cytotoxicity, endocrine-disrupting effects, oxidative stress of halophenolic disinfection byproducts and the underlying molecular mechanisms revealed by transcriptome analysis

Halophenolic disinfection byproducts (DBPs) are a class of emerging pollutants whose adverse effects on human cells and the underlying molecular mechanisms still need further exploration. In this study, we found that when halophenolic DBPs were substituted with the same halogen, the more substitution sites, the more cytotoxic, while when they were substituted at the same sites, the most toxic chemical was iodophenols, followed by bromophenols and chlorophenols. In addition, several of them exerted significant endocrine-disrupting effects at sublethal concentrations. 2,4,6-triiodophenol (TIP) and 2,4-dichlorophenol (2,4-DCP) showed the highest estradiol equivalent factor (EEF) of 4.41 × 10^-8 and flutamide equivalent factor (FEF) of 0.4, respectively. Furthermore, all of the halophenolic DBPs except for 2-chlorophenol (2-CP) and 2-bromophenol (2-BP) significantly increased the levels of reactive oxygen species (ROS) or 8-hydroxydeoxyguanosine (8-OHdG) in HepG2 cells. The lowest cytotoxicity and unchanged ROS and 8-OHdG levels after 2-CP exposure may result from the activation of the transporters of the adenosine triphosphate (ATP) binding cassette in cells. Transcriptome analysis revealed distinct grouping patterns of 2-CP, 2,6-dibromophenol (2,6-DBP), and TIP at the concentrations of EC₂₀, and the top differentially expressed genes (DEGs) were involved in the antioxidant-, immune-, and endocrine-associated systems. The weighted gene correlation network analysis well connected the phenotypes (EC₅₀, EEF, FEF, ROS, 8-OHdG, and ABC transporters) with the DEGs and revealed that the MAPK signaling pathway played a vital role in regulating the biological response after exposure to halophenolic DBPs. This study provides deep insights into the underlying mechanisms of the toxic effects induced by halophenolic DBPs.

Necrotizing Enterocolitis: The Role of Hypoxia, Gut Microbiome, and Microbial Metabolites

Necrotizing enterocolitis (NEC) is a life-threatening disease that predominantly affects very low birth weight preterm infants. Development of NEC in preterm infants is accompanied by high mortality. Surgical treatment of NEC can be complicated by short bowel syndrome, intestinal failure, parenteral nutrition-associated liver disease, and neurodevelopmental delay. Issues surrounding pathogenesis, prevention, and treatment of NEC remain unclear. This review summarizes data on prenatal risk factors for NEC, the role of pre-eclampsia, and intrauterine growth retardation in the pathogenesis of NEC. The role of hypoxia in NEC is discussed. Recent data on the role of the intestinal microbiome in the development of NEC, and features of the metabolome that can serve as potential biomarkers, are presented. The Pseudomonadota phylum is known to be associated with NEC in preterm neonates, and the role of other bacteria and their metabolites in NEC pathogenesis is also discussed. The most promising approaches for preventing and treating NEC are summarized.

TMT-based quantitative N-glycoproteomic analysis reveals glycoprotein protection can improve the quality of frozen bovine sperm

Cryopreservation of bovine semen plays a vital role in accelerating genetic improvement and elite breeding, but it has a detrimental effect on sperm quality, resulting in the decline of the reproductive efficiency. The glycosylation modification of protein has irreplaceable roles in spermatozoa. Herein, the effect of cryopreservation on glycoproteins of bovine spermatozoa has been studied for the first time using a tandem mass tag (TMT)-labeled quantitative glycoproteome. A total of 2598 proteins and 492 glycoproteins were identified, including 83 different expression proteins (DEPs) and 44 different expression glycosylated proteins (DEGPs) between fresh and frozen spermatozoa. Thirty-three DEPs are glycoproteins, which demonstrates that glycoproteins of bovine sperm were seriously affected by cryopreservation. Moreover, the effects include glycoprotein expression, glycosylation modification, and substructure localization for proteins such as glycoproteins TEX101, ACRBP, and IZOMU4. The biologic functions of the 115 changed proteins are mainly involved in sperm capacitation, migration in female genitalia, and sperm-egg interaction. Mostly key regulators were identified to be glycoproteins, which confirms that glycosylated proteins played important roles in bovine sperm. This comprehensive study of sperm glycoproteins helps to unravel the cryoinjury mechanisms, thus implying that glycoprotein protection should be an effective way to improve the quality of frozen sperm.

Defining roles of specific reactive oxygen species (ROS) in cell biology and physiology

'Reactive oxygen species' (ROS) is a generic term that defines a wide variety of oxidant molecules with vastly different properties and biological functions that range from signalling to causing cell damage. Consequently, the description of oxidants needs to be chemically precise to translate research on their biological effects into therapeutic benefit in redox medicine. This Expert Recommendation article pinpoints key issues associated with identifying the physiological roles of oxidants, focusing on H₂O₂ and O₂^.-. The generic term ROS should not be used to describe specific molecular agents. We also advocate for greater precision in measurement of H₂O₂, O₂^.- and other oxidants, along with more specific identification of their signalling targets. Future work should also consider inter-organellar communication and the interactions of redox-sensitive signalling targets within organs and whole organisms, including the contribution of environmental exposures. To achieve these goals, development of tools that enable site-specific and real-time detection and quantification of individual oxidants in cells and model organisms are needed. We also stress that physiological O₂ levels should be maintained in cell culture to better mimic in vivo redox reactions associated with specific cell types. Use of precise definitions and analytical tools will help harmonize research among the many scientific disciplines working on the common goal of understanding redox biology.

The multifaceted role of cytochrome P450-Derived arachidonic acid metabolites in diabetes and diabetic cardiomyopathy

Understanding lipid metabolism is a critical key to understanding the pathogenesis of Diabetes Mellitus (DM). It is known that 60-90% of DM patients are obese or used to be obese. The incidence of obesity is rising owing to the modern sedentary lifestyle that leads to insulin resistance and increased levels of free fatty acids, predisposing tissues to utilize more lipids with less glucose uptake. However, the exact mechanism is not yet fully elucidated. Diabetic cardiomyopathy seems to be associated with these alterations in lipid metabolism. Arachidonic acid (AA) is an important fatty acid that is metabolized to several bioactive compounds by cyclooxygenases, lipoxygenases, and the more recently discovered, cytochrome P450 (P450) enzymes. P450 metabolizes AA to either epoxy-AA (EETs) or hydroxy-AA (HETEs). Studies showed that EETs could have cardioprotective effects and beneficial effects in reversing abnormalities in glucose and insulin homeostasis. Conversely, HETEs, most importantly 12-HETE and 20-HETE, were found to interfere with normal glucose and insulin homeostasis and thus, might be involved in diabetic cardiomyopathy. In this review, we highlight the role of P450-derived AA metabolites in the context of DM and diabetic cardiomyopathy and their potential use as a target for developing new treatments for DM and diabetic cardiomyopathy.

Role of glycosyltransferases in carcinogenesis; growth factor signaling and EMT/MET programs

The glycosylation of cell surface receptors has been shown to regulate each step of signal transduction, including receptor trafficking to the cell surface, ligand binding, dimerization, phosphorylation, and endocytosis. In this review we focus on the role of glycosyltransferases that are involved in the modification of N-glycans, such as the effect of branching and elongation in signaling by various cell surface receptors. In addition, the role of those enzymes in the EMT/MET programs, as related to differentiation and cancer development, progress and therapy resistance is discussed.

Oxygen-Dependent Changes in the N-Glycome of Murine Pulmonary Endothelial Cells

Supplemental oxygen is frequently used together with mechanical ventilation to achieve sufficient blood oxygenation. Despite the undoubted benefits, it is vigorously debated whether too much oxygen can also have unpredicted side-effects. Uncertainty is also due to the fact that the molecular mechanisms are still insufficiently understood. The lung endothelium is covered with an exceptionally broad glycocalyx, carrying N- and O-glycans, proteoglycans, glycolipids and glycosaminoglycans. Glycan structures are not genetically determined but depend on the metabolic state and the expression level and activity of biosynthetic and glycan remodeling enzymes, which can be influenced by oxygen and the redox status of the cell. Altered glycan structures can affect cell interactions and signaling. In this study, we investigated the effect of different oxygen conditions on aspects of the glycobiology of the pulmonary endothelium with an emphasis on N-glycans and terminal sialylation using an in vitro cell culture system. We combined a proteomic approach with N-glycan structure analysis by LC-MS, qRT-PCR, sialic acid analysis and lectin binding to show that constant and intermittent hyperoxia induced time dependent changes in global and surface glycosylation. An siRNA approach identified St6gal1 as being primarily responsible for the early transient increase of α2-6 sialylated structures in response to hyperoxia.

COVID-19: A Redox Disease-What a Stress Pandemic Can Teach Us About Resilience and What We May Learn from the Reactive Species Interactome About Its Treatment

Significance: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing coronavirus disease 2019 (COVID-19), affects every aspect of human life by challenging bodily, socioeconomic, and political systems at unprecedented levels. As vaccines become available, their distribution, safety, and efficacy against emerging variants remain uncertain, and specific treatments are lacking. Recent Advances: Initially affecting the lungs, COVID-19 is a complex multisystems disease that disturbs the whole-body redox balance and can be long-lasting (Long-COVID). Numerous risk factors have been identified, but the reasons for variations in susceptibility to infection, disease severity, and outcome are poorly understood. The reactive species interactome (RSI) was recently introduced as a framework to conceptualize how cells and whole organisms sense, integrate, and accommodate stress. Critical Issues: We here consider COVID-19 as a redox disease, offering a holistic perspective of its effects on the human body, considering the vulnerability of complex interconnected systems with multiorgan/multilevel interdependencies. Host/viral glycan interactions underpin SARS-CoV-2's extraordinary efficiency in gaining cellular access, crossing the epithelial/endothelial barrier to spread along the vascular/lymphatic endothelium, and evading antiviral/antioxidant defences. An inflammation-driven "oxidative storm" alters the redox landscape, eliciting epithelial, endothelial, mitochondrial, metabolic, and immune dysfunction, and coagulopathy. Concomitantly reduced nitric oxide availability renders the sulfur-based redox circuitry vulnerable to oxidation, with eventual catastrophic failure in redox communication/regulation. Host nutrient limitations are crucial determinants of resilience at the individual and population level. Future Directions: While inflicting considerable damage to health and well-being, COVID-19 may provide the ultimate testing ground to improve the diagnosis and treatment of redox-related stress diseases. "Redox phenotyping" of patients to characterize whole-body RSI status as the disease progresses may inform new therapeutic approaches to regain redox balance, reduce mortality in COVID-19 and other redox diseases, and provide opportunities to tackle Long-COVID. Antioxid. Redox Signal. 35, 1226-1268.

The Lipocalin Apolipoprotein D Functional Portrait: A Systematic Review

Apolipoprotein D is a chordate gene early originated in the Lipocalin protein family. Among other features, regulation of its expression in a wide variety of disease conditions in humans, as apparently unrelated as neurodegeneration or breast cancer, have called for attention on this gene. Also, its presence in different tissues, from blood to brain, and different subcellular locations, from HDL lipoparticles to the interior of lysosomes or the surface of extracellular vesicles, poses an interesting challenge in deciphering its physiological function: Is ApoD a moonlighting protein, serving different roles in different cellular compartments, tissues, or organisms? Or does it have a unique biochemical mechanism of action that accounts for such apparently diverse roles in different physiological situations? To answer these questions, we have performed a systematic review of all primary publications where ApoD properties have been investigated in chordates. We conclude that ApoD ligand binding in the Lipocalin pocket, combined with an antioxidant activity performed at the rim of the pocket are properties sufficient to explain ApoD association with different lipid-based structures, where its physiological function is better described as lipid-management than by long-range lipid-transport. Controlling the redox state of these lipid structures in particular subcellular locations or extracellular structures, ApoD is able to modulate an enormous array of apparently diverse processes in the organism, both in health and disease. The new picture emerging from these data should help to put the physiological role of ApoD in new contexts and to inspire well-focused future research.