Cellular Redox Balance Research Articles

Unlocking marine microbial treasures: new PBP2a-targeted antibiotics elicited by metals and enhanced by RSM-driven transcriptomics and chemoinformatics.

Elicitation through abiotic stress, including heavy metals, is a new natural product drug discovery technique. In this research, three compounds 1, 2, and 6, were achieved by triggering zinc and nickel on marine Sphingomonas sp. and Streptomyces sp., which were absent in normal culture. Compound 5 was obtained for the first time from marine bacteria. All compounds showed potent antibacterial activity against Staphylococcus aureus and bactericidal effect at 300µm, but 6 was more active. The potent compound 6 production was further enhanced through response surface methodology by optimizing the condition consisting of nickel 1mM ions, 20mg/L sucrose, 30mg/L salt and culture time 14days. Under these conditions, the SM-6 production was enhanced with a yield of 6.3mg/L, which was absent in the normal culture. Further transcriptome analysis of compound 6 unveiled its antibacterial activity on S. aureus by modulating heat shock protein genes, disrupting protein folding and synthesis, and perturbing cellular redox balance, leading to a comprehensive inhibition of normal bacterial growth. In addition, ADMET has shown that all compounds are safe for cardiac and hepatotoxicity. To determine the anti-bacterial mechanism, all compounds were docked with PBP2a and DNA gyrase enzyme, and TLR-4 protein for predicting vaccine construct, and the best docking score was achieved against PBP2a enzyme with the highest score of -10.2 for compound 6. In-silico cloning was carried out to ensure the expression of proteins generated and were cloned using S.aureus as a host. The simulation studies have shown that both SM-6-PBP2a and TLR-4-PBP2a complex are stable with the system. This study presents a new approach to anti-bacterial drug discovery from microorganisms through heavy metals triggering and enhancing the compound production through response surface methodology.

Influence of CuO nanoparticles on photosystem II structural stability and functional activity of corn (Zea mays L.) under drought stress

Photoinhibition and photooxidation of photosystem II (PSII) is one of the key damages caused by drought stress. The present study aimed to assess whether or not foliar application of copper oxide nanoparticles (CuO NPs) is effective in promoting PSII stability and activity in corn plants under drought stress. Three-week old plants of corn were subjected to drought stress and varying levels of CuO nano-particles (0, 25, 50, and 100 mM) of the rooting medium. In this study, the effects of foliar application of copper oxide nanoparticles were assessed on growth, plant water status, nutrient uptake and structural stability of photosystem II of drought stressed corn plants. Drought stress impeded overall growth of the corn plants by reducing leaf relative water content, water potential, chlorophyll a content, and accumulation of K+ in plant leaves and roots. Exogenous application of 25 mM CuO NPs significantly enhanced the growth of corn. Exogenous application of CuO NPs improved the dry biomass and length of roots of the corn plants under drought stress. Although the application of nano-particles did not change leaf photosynthetic pigments, relative water content, K+ accumulation, it enhanced the accumulation of K+ in roots. Drought stress did not affect the structural stability of PSII, but it reduced its activity (performance index, PIABS) due to changes in the reaction center density and the biochemical reaction efficiency or electron transport capability. Exogenous application of CuO NPs improved PIABS due to increase in active reaction center density and electron transport efficiency. However, 100 mM CuO NPs application caused PSII damage at the donor end and reduced active reaction center density in the corn plants under both normal and drought stress conditions. The present findings provide a baseline information that foliar application of CuO-nanoparticles in low concentrations can improve the growth of corn by improving accumulation of K+ and increasing PSII activity. Further research is required to explore its effect on cellular redox balance and activities of PSII and PSI, and optimum dose of CuO-nanoparticles for developing formulations for their commercial applications in farmers’ fields.

Increased Red Cell Superoxide Dismutase Activity Is Associated with Cancer Risk: A Hidaka Cohort Study.

Our study is the first to show that increased R-SOD activity is associated with a significantly higher cancer risk in men but not in women. Antioxidative enzymes such as SOD are essential for maintaining cellular redox balance. Their roles in cancer development and prevention are yet to be fully elucidated.

Do Different Wheat Ploidy Levels Respond Differently Against Stripe Rust Infection: Interplay between Reactive Oxygen Species (ROS) and the Antioxidant Defense System?

Wheat stripe rust (Puccinia striiformis f. sp. tritici, Pst) is the most damaging wheat disease, causing substantial losses in global wheat production and productivity. Our study aimed to unravel the complex reciprocity between reactive oxygen species and the antioxidant defense system as a source of resistance against stripe rust in diploid, tetraploid and hexaploid wheat genotypes. The significant genetic variability for stripe rust in the materials under study was evident as the genotypes showed contrasting responses during both the adult and seedling stages. Our thorough perspective on the biochemical responses of wheat genotypes to stripe rust infection revealed distinct patterns in oxidative damage, antioxidant enzymes and photosynthetic pigments. Principal component analysis revealed inverse correlations between antioxidants and ROS, underscoring their key function in maintaining the cellular redox balance and protecting plants against oxidative damage. Diploid (Ae. tauschii) wild wheat exhibited a better biochemical defense system and greater resistance to stripe rust than the tetraploid (T. durum) and hexaploid (Triticum aestivum) wheat genotypes. The antioxidant enzyme activity of durum wheat was moderate compared to diploid and hexaploid wheat genotypes. The hexaploid wheat genotypes exhibited increased ROS production, reduced antioxidant enzyme activity and decreased photosynthetic pigment levels. This study enhances understanding of the antioxidant defense system across different wheat ploidies facing stripe rust, serving as a valuable strategy for improving crop disease resistance. This study validated the biochemical response of stripe rust-resistant and susceptible candidate genotypes, which will be used to develop genetic resources for discovering stripe rust resistance genes in wheat.

Monitoring Glutathione Content of the Endoplasmic Reticulum under Scrap Leather-Induced Endoplasmic Reticulum Stress via an Endoplasmic Reticulum-Targeted Two-Photon Fluorescent Probe.

Maintaining tissue homeostasis necessitates the coordinated efforts of various cell types to regulate inflammation. Endoplasmic reticulum (ER) stress, a hallmark of inflammation, exacerbates tissue pathology in various human diseases. Glutathione (GSH), a pivotal regulator of cellular redox balance, controls disulfide bond formation in the ER, thereby shielding cells from oxidative stress. In this study, we developed a two-photon fluorescent probe, ER-GSH, with specific ER targeting and demonstrated its high sensitivity and rapid response to GSH. Experiments conducted on BV2 cells and a mice model of neuroinflammation induced by scrap leather revealed that inflammatory reactions led to ER stress and a substantial reduction in GSH levels. Notably, the anti-inflammatory drug NS-398 effectively inhibited cell inflammation and ER stress by maintaining GSH levels. These findings underscore the potential therapeutic significance of modulating GSH levels to alleviate the impact of neuroinflammation.

Evaluation of oxidative stress biomarkers for differentiating bacterial and viral infections: a comparative study of glutathione disulfide (GSSG) and reduced glutathione (GSH)

Background and aims. This study evaluates the potential of oxidative stress biomarkers, specifically glutathione disulfide (GSSG) and reduced glutathione (GSH), for differentiating bacterial and viral infections. Oxidative stress plays a crucial role in the immune response, and glutathione is a key regulator of cellular redox balance. The aim was to assess whether differences in GSH and GSSG levels could be used as diagnostic markers for infection type. Methods. A chemiluminescence-based method evaluated GSH and GSSG as potential biomarkers for distinguishing between bacterial and viral infections. The GSH and GSSG concentrations were analyzed across bacterial, viral, and control groups. Results. Our data revealed significant differences in the GSH/GSSG ratio between the analyzed groups, with bacterial infections showing higher oxidative stress markers compared to viral infections. A combined analysis of GSH and GSSG concentrations, visualized through heatmaps and ROC curves, improved diagnostic accuracy, with clustering patterns distinguishing infection types. Conclusions. These findings suggest that the GSH/GSSG ratio could be used as a biomarker in distinguishing between bacterial and viral infections, offering potential clinical applications for more accurate diagnosis. Further research is required to validate these results in larger cohorts and to explore the underlying mechanisms of oxidative stress in pathogen-specific immune responses.

Selected Trace Elements and Their Impact on Redox Homeostasis in Eye Health

Oxidative stress plays a crucial role in the pathogenesis of various ocular degenerative diseases, leading to structural and functional changes in eye tissues. This imbalance between reactive oxygen species (ROS) and antioxidants significantly contributes to conditions such as age-related macular degeneration, diabetic retinopathy, cataracts, and glaucoma. Both enzymatic and nonenzymatic antioxidants are vital for maintaining ocular health by neutralizing ROS and restoring cellular redox balance. Essential trace elements, including iron, zinc, copper, and selenium, are fundamental for the proper functioning of these antioxidant systems. Iron is indispensable for enzymatic activity and cellular energy production, zinc supports numerous proteins involved in visual functions and antioxidant defense, copper is essential for various enzymatic reactions preventing oxidative stress, and selenium is critical for the activity of antioxidant enzymes such as glutathione peroxidase (GPX) and thioredoxin reductase (TrxR). This review summarizes current research on the complex interactions between oxidative stress and trace elements in ocular diseases, highlighting the therapeutic potential of antioxidant supplementation to mitigate oxidative damage and improve eye health. By integrating insights from studies on oxidative stress, trace elements, and eye physiology, this article underscores new diagnostic and therapeutic strategies that could lead to more effective prevention and treatment of ocular diseases, aiming to enhance clinical outcomes and guide future research in optimizing therapeutic strategies for eye health.

Viral Infections and the Glutathione Peroxidase Family: Mechanisms of Disease Development.

Significance: The glutathione peroxidase (GPx) family is recognized for its essential function in maintaining cellular redox balance and countering the overproduction of reactive oxygen species (ROS), a process intricately linked to the progression of various diseases including those spurred by viral infections. The modulation of GPx activity by viruses presents a critical juncture in disease pathogenesis, influencing cellular responses and the trajectory of infection-induced diseases. Recent Advances: Cutting-edge research has unveiled the GPx family's dynamic role in modulating viral pathogenesis. Notably, GPX4's pivotal function in regulating ferroptosis presents a novel avenue for the antiviral therapy. The discovery that selenium, an essential micronutrient for GPx activity, possesses antiviral properties has propelled us toward rethinking traditional treatment modalities. Critical Issues: Deciphering the intricate relationship between viral infections and GPx family members is paramount. Viral invasion can precipitate significant alterations in GPx function, influencing disease outcomes. The multifaceted nature of GPx activity during viral infections suggests that a deeper understanding of these interactions could yield novel insights into disease mechanisms, diagnostics, prognostics, and even chemotherapeutic resistance. Future Directions: This review aims to synthesize current knowledge on the impact of viral infections on GPx activity and expression and identify key advances. By elucidating the mechanisms through which GPx family members intersect with viral pathogenesis, we propose to uncover innovative therapeutic strategies that leverage the antioxidant properties of GPx to combat viral infections. The exploration of GPx as a therapeutic target and biomarker holds promise for the development of next-generation antiviral therapies. Antioxid. Redox Signal. 00, 000-000.

Metabolomic analysis of the browning and browning inhibition pulp of Fuji apple at different ripening stages

Apples at different ripening stages display distinct processing properties and browning characteristics in products. This study aimed to identify differential metabolites and metabolic pathways of browning pulp and browning inhibition pulp of Fuji apple across four ripening stages (M1–M4), corresponding to days after full bloom (DAFB: 148, 155, 162, and 171). We investigated the physicochemical characteristics, browning-related enzyme activities, and metabolomic profiles of apples at the four stages, revealing defensive metabolic changes associated with browning throughout ripening. Specifically, the browning rate in apples increased with ripening, peaking before declining in the late stages, and exhibited positive correlations with activities of polyphenol oxidase (PPO), peroxidase (POD), and catalase (CAT), and negative correlations with superoxide dismutase (SOD), phenylalanine ammonia-lyase (PAL), and H2O2 levels. Metabolomic profiling identified 315, 393, and 243 distinct metabolites in fresh control (FC), browning pulp (BR), and browning-inhibited pulps (CM) of apple at the four ripening stages, respectively. KEGG enrichment analysis revealed that FC and BR of the four ripening apples were differentiated by phenylpropanoid biosynthesis, while CM was featured by flavonoid biosynthesis. The characterized differential metabolites in BR were changed to α-linolenic acid metabolism with ripening, while those in CM were from flavonoid and phenylpropanoid biosynthesis. Furthermore, the in-depth analysis revealed 40 significantly differential metabolites associated with amino acid, nucleotide, coenzyme, and vitamin metabolism, potentially modulating the stress-responsive cellular redox balance. This research provides critical insights for browning prevention in the processing of fruits at various ripening stages.

Thioredoxin reductase inhibition and glutathione depletion mediated by glaucocalyxin A promote intracellular disulfide stress in gastric cancer cells.

Thioredoxin reductase 1 (TXNRD1) has been identified as one of the promising chemotherapeutic targets in cancer cells. Therefore, a novel TXNRD1 inhibitor could accelerate chemotherapy in clinical anticancer research. In this study, glaucocalyxin A (GlauA), a natural diterpene extracted from Rabdosia japonica var. glaucocalyx, was identified as a novel inhibitor of TXNRD1. We found that GlauA effectively inhibited recombinant TXNRD1 and reduced its activity in gastric cancer cells without affecting the enzyme's expression level. Mechanistically, the selenocysteine residue (U498) of TXNRD1 was irreversibly modified by GlauA through a Michael addition. Additionally, GlauA formed a covalent adduct with glutathione (GSH) and disrupted cellular redox balance by depleting cellular GSH. The inhibition of TXNRD1 and depletion of GSH by GlauA conferred its cytotoxic effects in spheroid culture and Transwell assays in AGS cells. The disulfide stress induced cytotoxicity of GlauA could be mitigated by adding reducing agents, such as DTT and β-ME. Furthermore, the FDA-approval drug auranofin, a TXNRD1 inhibitor, triggered oligomerization of the cytoskeletal protein Talin-1 in AGS cells, indicating that inhibiting TXNRD1 triggered disulfide stress. In conclusion, this study uncovered GlauA as an efficient inhibitor of TXNRD1 and demonstrated the potential of TXNRD1 inhibition as an effective anticancer strategy by disrupting redox homeostasis and inducing disulfide stress.

Ir(III) Diamine Transfer Hydrogenation Catalysts in Cancer Cells

AbstractThe development of catalytic metallodrugs is an emerging field that may offer new approaches to cancer chemotherapeutic design. By exploiting the unique properties of transition metal complexes, in‐cell catalysis can be applied to modulate the cellular redox balance as part of a multi‐targeting mechanism of action. We describe the synthesis and characterization of six coordinatively unsaturated iridium(III) diamine catalysts that are stable at physiological pH in aqueous solution. Reduction of the colorimetric substrate 2,6‐dichlorophenolindophenol by transfer hydrogenation under biologically compatible conditions achieved turnover frequencies up to 63 ± 2 h−1 and demonstrated that the source of hydride (sodium formate) is the limiting reagent, despite being in a 1000‐fold excess of the catalyst. The catalyst showed low in vivo acute toxicity in zebrafish embryos and modest in vitro potency towards cancer cells. When administered alone, the catalyst generated oxidative stress in cells (an effect that was conserved in vivo), but co‐treatment with a nontoxic dose of sodium formate negated this effect. Co‐treatment with sodium formate significantly enhanced catalyst potency in cancer cells (A2780 ovarian and MCF7 breast cancer cells) and drug‐resistant cells (A2780cis and MCF7‐TAMR1) but not in non‐tumorigenic cells (MRC5), demonstrating that a redox‐targeting mechanism may generate selectivity for cancer cells.

Ischemia-induced endogenous Nrf2/HO-1 axis activation modulates microglial polarization and restrains ischemic brain injury.

Cerebral ischemic stroke accounts for more than 80% of all stroke cases. During cerebral ischemia, reactive oxygen species produced in the ischemic brain induce oxidative stress and inflammatory responses. Nrf2 is a transcription factor responsible for regulating cellular redox balance through the induction of protective antioxidant and phase II detoxification responses. Although the induction of endogenous Nrf2/HO-1 axis activation has been observed in the ischemic brain, whether ischemia-induced endogenous Nrf2/HO-1 axis activation plays a role in modulating microglia (MG) phenotypes and restraining ischemic brain injury is not characterized and requires further exploration. To investigate that, we generated mice with Nrf2 knockdown specifically in MG to rigorously assess the role of endogenous Nrf2 activation in ischemic brain injury after stroke. Our results showed that MG-specific Nrf2 knockdown exacerbated ischemic brain injury after stroke. We found that Nrf2 knockdown altered MG phenotypes after stroke, in which increased frequency of inflammatory MG and decreased frequency of anti-inflammatory MG were detected in the ischemic brain. Moreover, we identified attenuated Nrf2/HO-1 axis activation led to increased CD68/IL-1β and suppressed CD206 expression in MG, resulting in aggravated inflammatory MG in MG-specific Nrf2 knockdown mice after stroke. Intriguingly, using type II diabetic preclinical models, we revealed that diabetic mice exhibited attenuated Nrf2/HO-1 axis activation in MG and exacerbated ischemic brain injury after stroke that phenocopy mice with MG-specific Nrf2 knockdown. Finally, the induction of exogenous Nrf2/HO-1 axis activation in MG through pharmacological approaches ameliorated ischemic brain injury in diabetic mice. In conclusion, our findings provide cellular and molecular insights demonstrating ischemia-induced endogenous Nrf2/HO-1 axis activation modulates MG phenotypes and restrains ischemic brain injury. These results further strengthen the therapeutic potential of targeting Nrf2/HO-1 axis in MG for the treatment of ischemic stroke and diabetic stroke.

Sensitization of Multidrug Resistant Cancer Cells to Doxorubicin Using Ebselen by Disturbing Cellular Redox Status.

Multidrug resistance (MDR) poses a significant problem in cancer treatment, often causing adverse effects during chemotherapy. Ebselen (Ebs), a synthetic organoselenium compound, affects cellular redox status in cancer cells. In the study, we observed that Ebs disrupted cellular redox balance and sensitized drug-resistant cells to doxorubicin (DOX) treatment. The combination of Ebs and DOX led to increased intracellular reactive oxygen species (ROS) levels and lipid peroxidation while decreasing the activity of thioredoxin reductase (TrxR) and cellular antioxidants in drug-resistant cells. Furthermore, this combination treatment demonstrated notable chemosensitizing effects by reducing cell viability and proliferation in MDR cells compared to DOX treatment alone. Additionally, the combination of Ebs and DOX induced DNA fragmentation and exhibited G2/M phase cell cycle arrest. Immunofluorescent analysis revealed that the Ebs and DOX combination upregulated the expression of p53 and p21, which activated the mitochondrial-dependent apoptotic pathway. The combination treatment also enhanced the upregulation of proapoptotic markers such as Bax, Caspase-3, -9, and cytochrome C, while downregulating the expression of the antiapoptotic marker Bcl-2. Therefore, the current discoveries suggest that Ebs could be employed as a drug candidate for reversing MDR in cancer cells by regulating cellular redox homeostasis.

O-GlcNAcylation promotes malignancy and cisplatin resistance of lung cancer by stabilising NRF2.

The transcription factor NRF2 plays a significant role in regulating genes that protect cells from oxidative damage. O-GlcNAc modification, a type of posttranslational modification, is crucial for cellular response to stress. Although the involvement of both NRF2 and O-GlcNAc in maintaining cellular redox balance and promoting cancer malignancy has been demonstrated, the potential mechanisms remain elusive. The immunoblotting, luciferase reporter, ROS assay, co-immunoprecipitation, and immunofluorescence was used to detect the effects of global cellular O-GlcNAcylation on NRF2. Mass spectrometry was utilised to map the O-GlcNAcylation sites on NRF2, which was validated by site-specific mutagenesis and O-GlcNAc enzymatic labelling. Human lung cancer samples were employed to verify the association between O-GlcNAc and NRF2. Subsequently, the impact of NRF2 O-GlcNAcylation in lung cancer malignancy and cisplatin resistance were evaluated in vitro and in vivo. NRF2 is O-GlcNAcylated at Ser103 residue, which hinders its binding to KEAP1 and thus enhances its stability, nuclear localisation, and transcription activity. Oxidative stress and cisplatin can elevate the phosphorylation of OGT at Thr444 through the activation of AMPK kinase, leading to enhanced binding of OGT to NRF2 and subsequent elevation of NRF2 O-GlcNAcylation. Both in cellular and xenograft mouse models, O-GlcNAcylation of NRF2 at Ser103 promotes the malignancy of lung cancer. In human lung cancer tissue samples, there was a significant increase in global O-GlcNAcylation, and elevated levels of NRF2 and its O-GlcNAcylation compared to paired adjacent normal tissues. Chemotherapy promotes NRF2 O-GlcNAcylation, which in turn decreases cellular ROS levels and drives lung cancer cell survival. Our findings indicate that OGT O-GlcNAcylates NRF2 at Ser103, and this modification plays a role in cellular antioxidant, lung cancer malignancy, and cisplatin resistance.

Antioxidant Features of Humic Products by ABTS Assay.

Oxidative stress plays a pivotal role in driving immunosenescence by disrupting cellular homeostasis and impairing immune function. Humic substances exhibit scavenging activity against reactive oxygen species (ROS), inhibit ROS generation via metal chelation, and modulate endogenous antioxidant enzyme activity. Additionally, humic substances display anti-inflammatory effects, further supporting cellular redox balance. Given their antioxidant activity, humic substances hold promise as natural compounds for mitigating oxidative stress-associated immunosenescence. Here we describe the evaluation of antioxidant capacities of humic products by ABTS spectrophotometric assay.

Oncolytic Vaccinia Virus Encoding Aphrocallistes vastus Lectin Suppresses the Proliferation of Gastric Cancer Cells.

Our previous research has demonstrated that the oncolytic vaccinia virus encoding Aphrocallistes vastus lectin (oncoVV-AVL), an oncolytic vaccinia virus engineered to carry the AVL, exhibits potent cytotoxic effects on colorectal and hepatocellular cancer cells. Based on this foundation, we undertook a series of experiments to explore its efficacy on gastric cancer (GC) cells. Our findings revealed that oncoVV-AVL significantly increased reactive oxygen species levels and suppressed the expression of nuclear factor erythroid 2-related factor 2, thereby enhancing viral replication and disrupting the cellular redox balance, ultimately leading to the demise of cancer cells. Additionally, our investigations uncovered that oncoVV-AVL reprogrammed the metabolic microenvironment to favor viral replication, culminating in the lysis of cancer cells. Furthermore, we observed that oncoVV-AVL not only regressed tumor growth but also induced tumor tissue necrosis. These promising results suggest potential new avenues for the therapeutic management of GC.

Elucidating the Role of Sirtuin 3 in Mammalian Oocyte Aging.

The field of reproductive biology has made significant progress in recent years, identifying specific molecular players that influence oocyte development and function. Among them, sirtuin 3 (SIRT3) has attracted particular attention for its central role in mediating mitochondrial function and cellular stress responses in oocytes. So far, studies have demonstrated that the knockdown of SIRT3 leads to a decrease in blastocyst formation and an increase in oxidative stress within an embryo, underscoring the importance of SIRT3 in maintaining the cellular redox balance critical for embryonic survival and growth. Furthermore, the literature reveals specific signaling pathways, such as the SIRT3- Glycogen synthase kinase-3 beta (GSK3β) deacetylation pathway, crucial for mitigating oxidative stress-related anomalies in oocyte meiosis, particularly under conditions like maternal diabetes. Overall, the emerging role of SIRT3 in regulating oocyte mitochondrial function and development highlights the critical importance of understanding the intricate connections between cellular metabolism, stress response pathways, and overall reproductive health and function. This knowledge could lead to the development of novel strategies to support oocyte quality and fertility, with far-reaching implications for assisted reproductive technologies and women's healthcare. This commentary aims to provide an overview of the importance of SIRT3 in oocytes by synthesizing results from a multitude of studies. The aim is to elucidate the role of SIRT3 in oocyte development, maturation, and aging and to identify areas where further research is needed.

Deletion of CD38 mitigates the severity of NEC in experimental settings by modulating macrophage-mediated inflammation

Necrotizing enterocolitis (NEC) is a form of potentially lethal gastrointestinal inflammation that primarily affects preterm neonates. It is crucial to recognize that, while the disease carries significant risks, timely and effective medical intervention can greatly enhance the chances of survival. Additionally, NEC is closely linked to the activation of macrophages, highlighting the complex interplay between the immune response and disease progression. CD38, acting as an ectoenzyme, catalyzes the hydrolysis of NAD+ to produce cyclic ADP-ribose (cADPR), a reaction critical for modulating cellular redox balance and energy homeostasis. This enzymatic activity is particularly pertinent in the context of necrotizing enterocolitis (NEC). In this research, we investigated whether CD38 deletion can elevate NAD+ levels to reduce macrophage-mediated inflammation and improve NEC severity. We show that NEC patients was associated with the increased CD38 expression in intestine and blood. These results were also observed in NEC mice, and CD38 deletion ameliorated NEC intestinal injury. Mechanistically, CD38 deletion elevated NAD+ levels that reduced oxidative stress and intestinal inflammation. Furthermore, CD38 deletion promoted M2 macrophage polarization, inhibited macrophage activation and phagocytosis ability. Thus, our results reveal a critical role for CD38 as an intracellular immune regulator for regulating macrophage activation and intestinal inflammation in NEC. Targeting CD38 and NAD+ signal maybe a promising strategy for treatment of NEC.

Hepsin as a potential therapeutic target for alleviating acetaminophen-induced hepatotoxicity via gap-junction regulation and oxidative stress modulation

Acetaminophen (APAP) overdose is a leading cause of drug-induced liver damage, highlighting the limitations of current emergency treatments that primarily involve administering the glutathione precursor N-acetylcysteine and supportive therapy. This study highlights the essential protective role of the type II transmembrane serine protease (TTSP), hepsin, in mitigating acetaminophen-induced liver injury, particularly through its regulation of gap junction (GJ) abundance in response to reactive oxygen stress in the liver. We previously reported that reduced levels of activated hepatocyte growth factor and the c-Met receptor tyrosine kinase—both of which are vital for maintaining cellular redox balance—combined with increased expression of GJ proteins in hepsin-deficient mice. Here, we show that hepsin deficiency in mice exacerbates acetaminophen toxicity compared to wild-type mice, leading to more severe liver pathology, elevated oxidative stress, and greater mortality within 6 h after exposure. Administering hepsin had a protective effect in both mouse models, reducing hepatotoxicity by modulating GJ abundance. Additionally, transcriptome analysis and a functional GJ inhibitor have highlighted hepsin's mechanism for managing oxidative stress. Combining hepsin with relatively low doses of N-acetylcysteine had a synergistic effect that was more efficacious than high-dose N-acetylcysteine alone. Our results illustrate the crucial role of hepsin in modulating the abundance of hepatic GJs and reducing oxidative stress, thereby offering early protection against acetaminophen-induced hepatotoxicity and a new, combination approach. Emerging as a promising therapeutic target, hepsin holds potential for combination therapy with N-acetylcysteine, paving the way for novel approaches in managing drug-induced liver injury.Graphical 1. Hepsin−/− mice exhibit exacerbated APAP toxicity, resulting in more severe liver damage, elevated oxidative stress, and higher mortality.2. Hepsin is crucial in protecting against APAP-induced liver injury by regulating gap junctions and reducing oxidative stress.3. Combining hepsin with low doses of N-acetylcysteine provides greater protection against APAP-induced hepatotoxicity than high-dose NAC alone.

A new method for quantifying glyoxalase II activity in biological samples.

Glyoxalase II (Glo II) is a crucial enzyme in the glyoxalase system, and plays a vital role in detoxifying harmful metabolites and maintaining cellular redox balance. Dysregulation of Glo II has been linked to various health conditions, including cancer and diabetes. This study introduces a novel method using 2,4-dinitrophenylhydrazine (2,4-DNPH) to measure Glo II activity. The principle behind this approach is the formation of a colored hydrazone complex between 2,4-DNPH and pyruvate produced by the Glo II-catalyzed reaction. Glo II catalyzes the hydrolysis of S-D-lactoylglutathione (SLG), generating D-lactate and reduced glutathione (GSH). The D-lactate is then converted to pyruvate by lactate dehydrogenase, then reacting with 2,4-DNPH to form a brown-colored hydrazone product. The absorbance of this complex, measured at 430 nm, allows for the quantification of Glo II activity. The study rigorously validates the 2,4-DNPH method, demonstrating its stability, sensitivity, linearity, and resistance to interference from various biochemical substances. Compared to the existing UV method, this 2,4-DNPH-Glo II assay shows a strong correlation. The new protocol for measuring Glo II activity using 2,4-DNPH is simple, cost-effective, and accurate, making it a valuable tool for researchers and medical professionals. Its potential for widespread use in various laboratory settings, from academic research to clinical diagnostics, offers significant opportunities for future research and medical applications.