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

Enhanced release of volatile halocarbons of microalgae in response to antibiotic-induced stress: Based on laboratory and ship-field experiments

This study investigated the impacts of sulfamethazine (SMZ) and oxytetracycline (OTC) antibiotics on the marine microalgae Nitzschia closterium and its release of volatile halocarbons (VHCs), which contribute to ozone depletion and climate change. High concentrations of SMZ and OTC suppressed cell density, reduced chlorophyll a content, and hindered Fv/Fm elevation in N. closterium, indicating its growth was inhibited. The exposure of N. closterium to antibiotics led to increased reactive oxygen species (ROS), reduced soluble protein content, and heightened catalase (CAT) activity, indicative of increased oxidative stress. This stress increased the release of three VHCs (CHBrCl2, CHBr2Cl, and CHBr3). Ship-borne experiments showed that high phytoplankton biomass was linked to high VHC release. Notably, the production and release of VHCs were significantly higher in the high-concentration antibiotic group (100 μg/L) than the low-concentration group (0.1 μg/L). These findings suggested that antibiotics induce excess ROS in algal cells, stimulating VHC production and release.

Bimetal-organic framework-integrated electrochemical sensor for on-chip detection of H2S and H2O2 in cancer tissues

Studies on the interaction between hydrogen sulfide (H2S) and hydrogen peroxide (H2O2) in redox signaling motivate the development of a sensitive sensing platform for their discriminatory and dynamic detection. Herein, we present a fully integrated microfluidic on-chip electrochemical sensor for the online and simultaneous monitoring of H2S and H2O2 secreted by different biological samples. The sensor utilizes a cicada-wing-like RuCu bimetal-organic framework with uniform nanorods architecture that grows on a flexible carbon fiber microelectrode. Owing to the optimized electronic structural merits and satisfactory electrocatalytic properties, the resultant microelectrode shows remarkable electrochemical sensing performance for sensitive and selective detection of H2S and H2O2 at the same time. The result exhibits low detection limits of 0.5 μM for H2S and 0.1 μM for H2O2, with high sensitivities of 61.93 μA cm-2 mM-1 for H2S, and 75.96 μA cm-2 mM-1 for H2O2. The integration of this biocompatible microelectrode into a custom wireless microfluidic chip enables the construction of a miniature intelligent system for in situ monitoring of H2S and H2O2 released from different living cells to differentiate between cancerous and normal cells. When applied for real-time tracking of H2S and H2O2 secreted by colorectal cancer tissues, it allows the evaluation of their chemotherapeutic efficacy. These findings hold paramount implications for disease diagnosis and therapy.

Theoretical insights into a turn-on fluorescence probe based on naphthalimide for peroxynitrite detection

Compared with other reactive oxygen species, peroxynitrite (ONOO-) has diversified reactions and transformations in organisms, and its specific action mechanism is not very clear. The study of reactive oxygen species is of great significance in the field of physiology and pathology. Recently an effective on/off fluorescent probe HCA-OH was designed by Liu et al. through tethering p-aminophenol to 1,8-naphthalimide directly. The probe HCA-OH could release the fluorophore HCA-NH2 with good photostability and high fluorescence quantum yield under oxidation of ONOO- via dearylation process. In this work, the sensing mechanism and spectrum character of probe HCA-OH were studied in detail under quantum chemistry calculation. The electronic structures, reaction sites and fluorescent properties of the probe were theoretically analyzed to benefit us for in-depth understanding the principle of detection on reactive oxygen species (ONOO-) with the fluorescent probe HCA-OH. These theoretical results could inspire the medical research community to design and synthesize highly efficient fluorescent probe for reactive oxygen species detection.

Strong associations between fasting lipids and glucose concentrations and ALT levels strengthened with increasing ALT quantiles

BACKGROUND

A persistent redox state and excessive reactive species involved in carbohydrate and lipid metabolism lead to oxidative damage in the liver, however, how fasting plasma concentrations of lipids and glucose are associated with fasting blood levels of alanine transaminase (ALT) and aspartate transaminase (AST) remains to be evaluated in large-scale population.

METHODS

A cross-sectional study with 182,971 residents aged 18 to 92 years; multidimensional stratified analyses including quantile linear regression analysis and sex stratification were adopted to improve the quality of the evidence.

RESULTS

The associations between the concentrations of non-HDL-C and triglyceride and ALT levels were positive, stronger in males in each quantile of ALT levels and the coefficients expanded with increasing ALT levels at slopes of 3.610 and 5.678 in males and 2.977 and 5.165 in females, respectively. The associations between the HDL-C concentrations and ALT levels were negative, also stronger in males in each quantile and the coefficients expanded with increasing ALT levels at slopes of -7.839 in females and - 5.797 in males. The associations between glucose concentrations and ALT levels were positive, but stronger in females in each quantile and the coefficients expanded with increasing ALT levels at slopes of 1.736 in males and 2.177 in females, respectively. Similar pattern consist of relatively weaker coefficients and slops were observed between concentrations of non-HDL-C, triglyceride and glucose and AST levels. The associations between albumin concentration and concentrations of blood lipids and glucose were relatively steady across all quantiles.

CONCLUSIONS

The dose dependent effect between blood concentrations of lipids and glucose and liver function changes suggests that excessive carbohydrate and lipid metabolism may cause subclinical liver damage. Long term sustained primary and secondary inflammatory factors produced in the liver might be transmitted to adjacent organs, such as the heart, kidneys, and lungs, to cause and/or exacerbate pathological changes in these visceral organs.

In Vivo Antioxidant Activity of Common Dietary Flavonoids: Insights from the Yeast Model Saccharomyces cerevisiae

BACKGROUND

Oxidative stress, associated with diseases and aging, underscores the therapeutic potential of natural antioxidants. Flavonoids, known for scavenging free radicals and modulating cell signaling, offer significant health benefits and contribute to longevity. To explore their in vivo effects, we investigated the antioxidant activity of quercetin, apigenin, luteolin, naringenin, and genistein, using Saccharomyces cerevisiae as a model organism.

METHODS

We performed viability assays to evaluate the effects of these compounds on cell growth, both in the presence and absence of H2O2. Additional assays, including spot assays, drug drop tests, and colony-forming unit assays, were also conducted.

RESULTS

Viability assays indicated that the tested compounds are non-toxic. H2O2 reduced yeast viability, but flavonoid-treated cells showed increased resistance, confirming their protective effect. Polyphenols scavenged intracellular reactive oxygen species (ROS) and protected cells from oxidative damage. Investigations into defense systems revealed that H2O2 induced catalase activity and oxidized glutathione accumulation, both of which were reduced by polyphenol treatment.

CONCLUSIONS

The tested natural compounds enhance cell viability and reduce oxidative damage by scavenging ROS and modulating antioxidant defenses. These results suggest their potential as supplements and pave the way for further research.

Ammonia-induced lysosomal and mitochondrial damage causes cell death of effector CD8+ T cells

Ammonia is thought to be a cytotoxin and its increase in the blood impairs cell function. However, whether and how this toxin triggers cell death under pathophysiological conditions remains unclear. Here we show that ammonia induces a distinct form of cell death in effector T cells. We found that rapidly proliferating T cells use glutaminolysis to release ammonia in the mitochondria, which is then translocated to and stored in the lysosomes. Excessive ammonia accumulation increases lysosomal pH and results in the termination of lysosomal ammonia storage and ammonia reflux into mitochondria, leading to mitochondrial damage and cell death, which is characterized by lysosomal alkalization, mitochondrial swelling and impaired autophagic flux. Inhibition of glutaminolysis or blocking lysosomal alkalization prevents ammonia-induced T cell death and improves T cell-based antitumour immunotherapy. These findings identify a distinct form of cell death that differs from previously known mechanisms.

Singlet Oxygen Photophysics: From Liquid Solvents to Mammalian Cells

Molecular oxygen, O2, has long provided a cornerstone for studies in chemistry, physics, and biology. Although the triplet ground state, O2(X3Σg-), has garnered much attention, the lowest excited electronic state, O2(a1Δg), commonly called singlet oxygen, has attracted appreciable interest, principally because of its unique chemical reactivity in systems ranging from the Earth's atmosphere to biological cells. Because O2(a1Δg) can be produced and deactivated in processes that involve light, the photophysics of O2(a1Δg) are equally important. Moreover, pathways for O2(a1Δg) deactivation that regenerate O2(X3Σg-), which address fundamental principles unto themselves, kinetically compete with the chemical reactions of O2(a1Δg) and, thus, have practical significance. Due to technological advances (e.g., lasers, optical detectors, microscopes), data acquired in the past ∼20 years have increased our understanding of O2(a1Δg) photophysics appreciably and facilitated both spatial and temporal control over the behavior of O2(a1Δg). One goal of this Review is to summarize recent developments that have broad ramifications, focusing on systems in which oxygen forms a contact complex with an organic molecule M (e.g., a liquid solvent). An important concept is the role played by the M+•O2-• charge-transfer state in both the formation and deactivation of O2(a1Δg).

Developing a vanillin-derived imidazo-pyridin-containing fluorescent probe for imaging cysteine in living pulmonary cells under oxygen supply variation

In this work, derived from vanillin and imidazo-pyridin backbone, a fluorescent probe IPV-Cys was developed for imaging the cysteine (Cys) level in living pulmonary cells under oxygen supply variation. By mimicking the oxygen supply variation in both the solution test and cellular imaging, the optical performance and imaging effect of IPV-Cys was investigated. In the solution system, the oxygen supply variation caused no impact on the reporting signals. The fluorescence reporting signal intensity at 490 nm suggested the enhancement along with the increase of the Cys concentration. The advantages of IPV-Cys included relatively high sensitivity, high stability, and high selectivity. On the basis of the low cyto-toxicity, IPV-Cys achieved the monitoring the endogenous Cys level in in living pulmonary cells and the impact of the oxygen supply variation by reporting fluorescence signals. The information here was meaningful for both the pre-clinical diagnosis and surgical techniques.

In Rhodotorula mucilaginosa, active oxidative metabolism increases carotenoids to inactivate excess reactive oxygen species

Carotenoids produced by bacteria, yeasts, algae and plants inactivate Free Radicals (FR). However, FR may inactivate carotenoids and even turn them into free radicals. Oxidative metabolism is a source of the highly motile Reactive Oxygen Species (ROS). To evaluate carotenoid interactions with ROS, the yeast Rhodotorula mucilaginosa was grown in dextrose (YPD), a fermentative substrate where low rates of oxygen consumption and low carotenoid expression were observed, or in lactate (YPLac), a mitochondrial oxidative-phosphorylation (OxPhos) substrate, which supports high respiratory activity and carotenoid production. ROS were high in YPLac-grown cells and these were unmasked by the carotenoid production-inhibitor diphenylamine (DPA). In contrast, in YPD-grown cells ROS were almost absent. It is proposed that YPLac cells are under oxidative stress. In addition, YPLac-grown cells were more sensitive than YPD-grown cells to menadione (MD), a FR-releasing agent. To test whether carotenoids from cells grown in YPLac had been modified by ROS, carotenoids from each, YPD- and YPLac-grown cells were isolated and added back to cells, evaluating protection from MD. Remarkably, carotenoids extracted from cells grown in YPLac medium inhibited growth, while in contrast extracts from YPD-grown cells were innocuous or mildly protective. Results suggest that carotenoid-synthesis in YPLac-cells is a response to OxPhos-produced ROS. However, upon reacting with FR, carotenoids themselves may be inactivated or even become prooxidant themselves.

Endogenous electrophiles and peroxymonocarbonate can link tyrosine phosphorylation cascades with the cytosolic TXNRD1 selenoprotein and the KEAP1/NRF2 system

Endogenously formed reactive molecules, such as lipid peroxides, 4-hydroxynonenal, methylglyoxal and other reactive oxygen species, can have major effects on cells. Accumulation of these molecules is counteracted by antioxidant enzymes, including the glutathione (GSH) and thioredoxin (Trx) systems, in turn regulated by the KEAP1/NRF2 system. Receptor tyrosine kinases (RTK) and their counteracting protein tyrosine phosphatases (PTP) are also modulated through redox regulation of PTP activities. The cytosolic selenoprotein thioredoxin reductase (TXNRD1) is particularly prone to attack at its easily accessible catalytic selenocysteine (Sec) residue by reactive electrophilic compounds. Therefore, we here discuss how endogenously formed electrophiles can modulate RTK/PTP signaling in a concentration- and time dependent manner by reactions either directly or indirectly linking TXNRD1 with the KEAP1/NRF2 system. Moreover, recent findings suggest that endogenous formation of peroxymonocarbonate can efficiently inhibit PTP activities and stimulate RTK signaling, seemingly bypassing PTP reduction as otherwise supported by the GSH/Trx systems.

Indole-3-Butyric Acid, a Natural Auxin, Protects against Fenton Reaction-Induced Oxidative Damage in Porcine Thyroid

We present results on the potential protective antioxidant properties of indole-3-butyric acid. Indole-3-butyric acid is an indole derivative defined as an auxin and widely known as a plant growth regulator. It naturally occurs in Arabidopsis thaliana, which is applied as a model plant in genetic studies. Oxidative damage to membrane lipids (lipid peroxidation; LPO) in porcine thyroid homogenates was induced by Fenton reaction substrates (Fe2+ + H2O2). Iron (Fe2+) was used in very high concentrations of 1200, 600, 300, 150, 75, 37.5, 18.75, 9.375, 4.687, and 2.343 µM. Indole-3-butyric acid (10.0, 5.0, 2.5, 1.25, and 0.625 mM) was applied to check whether it prevents the above process. The LPO level, expressed as malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA) concentration, was measured spectrophotometrically. Expectedly, Fenton reaction substrates, in a Fe2+ concentration-dependent manner, increased LPO level, with the lowest effective concentration of iron being 9.375 µM. In the case of almost all concentrations of indole-3-butyric acid, this auxin has exhibited very promising antioxidant protection, with the most effective concentrations being 10.0 and 5.0 mM; however, as low concentrations of indole-3-butyric acid at 1.25 mM was still effective. Indole-3-butyric acid used alone did not change the basal level of LPO, which is a favourable effect. To summarise, indole-3-butyric acid has protective antioxidant properties against experimentally induced oxidative damage to membrane lipids in the thyroid, and this is for the first time documented in the literature. This compound can be considered a natural protective agent present in plants, which can serve as a dietary nutrient.

Toward decoding spatiotemporal signaling activities of reactive immunometabolites with precision immuno-chemical biology tools

Immune-cell reprogramming driven by mitochondria-derived reactive electrophilic immunometabolites (mt-REMs-e.g., fumarate, itaconate) is an emerging phenomenon of major biomedical importance. Despite their localized production, mt-REMs elicit significantly large local and global footprints within and across cells, through mechanisms involving electrophile signaling. Burgeoning efforts are being put into profiling mt-REMs' potential protein-targets and phenotypic mapping of their multifaceted inflammatory behaviors. Yet, precision indexing of mt-REMs' first-responders with spatiotemporal intelligence and locale-specific function assignments remain elusive. Highlighting the latest advances and overarching challenges, this perspective aims to stimulate thoughts and spur interdisciplinary innovations to address these unmet chemical-biotechnological needs at therapeutic immuno-signaling frontiers.

Reactive oxygen species (ROS)-responsive biomaterials for treating myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a critical issue that arises when restoring blood flow after an ischemic event in the heart. Excessive reactive oxygen species (ROS) production during this process exacerbates cellular damage and impairs cardiac function. Recent therapeutic strategies have focused on leveraging the ROS microenvironment to design targeted drug delivery systems. ROS-responsive biomaterials have emerged as promising candidates, offering enhanced therapeutic efficacy with reduced systemic adverse effects. This review examines the mechanisms of ROS overproduction during myocardial ischemia-reperfusion and summarizes significant advancements in ROS-responsive biomaterials for MIRI treatment. We discuss various chemical strategies to impart ROS sensitivity to these materials, emphasizing ROS-induced solubility switches and degradation mechanisms. Additionally, we highlight various ROS-responsive therapeutic platforms, such as nanoparticles and hydrogels, and their unique advantages in drug delivery for MIRI. Preclinical studies demonstrating the efficacy of these materials in mitigating MIRI in animal models are reviewed, alongside their mechanisms of action and potential clinical implications. We also address the challenges and future prospects of translating these state of the art biomaterial-based therapeutics into clinical practice to improve MIRI management and cardiac outcomes. This review will provide valuable insights for researchers and clinicians working on novel therapeutic strategies for MIRI intervention.

Tumor Microenvironment Responsive RNA Drug Delivery Systems: Intelligent Platforms for Sophisticated Release

Cancer is a significant health concern, increasingly showing insensitivity to traditional treatments, highlighting the urgent need for safer and more practical treatment options. Ribonucleic acid (RNA) gene therapy drugs have demonstrated promising potential in preclinical and clinical trials for antitumor therapy by regulating tumor-related gene expression. However, RNA's poor membrane permeability and stability restrict its effectiveness in entering and being utilized in cells. An appropriate delivery system is crucial for achieving targeted tumor effects. The tumor microenvironment (TME), characterized by acidity, hypoxia, enzyme overexpression, elevated glutathione (GSH) concentration, and excessive reactive oxygen species (ROS), is essential for tumor survival. Furthermore, these distinctive features can also be harnessed to develop intelligent drug delivery systems. Various nanocarriers that respond to the TME have been designed for RNA drug delivery, showing the advantages of tumor targeting and low toxicity. This Review discusses the abnormal changes of components in TME, therapeutic RNAs' roles, underlying mechanisms, and the latest developments in utilizing vectors that respond to microenvironments for treating tumors. We hope it provides insight into creating and optimizing RNA delivery vectors to improve their effectiveness.

Contribution of oxidation reactions to photo-induced damage to cellular DNA

This review article is aimed at providing updated information on the contribution of immediate and delayed oxidative reactions to the photo-induced damage to cellular DNA/skin under exposure to UVB/UVA radiations and visible light. Low-intensity UVC and UVB radiations that operate predominantly through direct excitation of the nucleobases are very poor oxidizing agents giving rise to very low amounts of 8-oxo-7,8-dihydroguanine and DNA strand breaks with respect to the overwhelming bipyrimidine dimeric photoproducts. The importance of these two classes of oxidatively generated damage to DNA significantly increases together with a smaller contribution of oxidized pyrimidine bases upon UVA irradiation. This is rationalized in terms of sensitized photooxidation reactions predominantly mediated by singlet oxygen together with a small contribution of hydroxyl radical that appear to also be implicated in the photodynamic effects of the blue light component of visible light. Chemiexcitation-mediated formation of "dark" cyclobutane pyrimidine dimers in UVA-irradiated melanocytes is a recent major discovery that implicates in the initial stage, a delayed generation of reactive oxygen and nitrogen species giving rise to triplet excited carbonyl intermediate and possibly singlet oxygen. High-intensity UVC nanosecond laser radiation constitutes a suitable source of light to generate pyrimidine and purine radical cations in cellular DNA via efficient biphotonic ionization.

Interference of ATP-Adenosine Axis by Engineered Biohybrid for Amplifying Immunogenic Cell Death-Mediated Antitumor Immunotherapy

Immunogenic cell death (ICD) often results in the production and accumulation of adenosine (ADO), a byproduct that negatively impacts the therapeutic effect as well as facilitates tumor development and metastasis. Here, an innovative strategy is elaborately developed to effectively activate ICD while avoiding the generation of immunosuppressive adenosine. Specifically, ZIF-90, an ATP-responsive consumer, is synthesized as the core carrier to encapsulate AB680 (CD73 inhibitor) and then coated with an iron-polyphenol layer to prepare the ICD inducer (AZTF), which is further grafted onto prebiotic bacteria via the esterification reaction to obtain the engineered biohybrid (Bc@AZTF). Particularly, the designed Bc@AZTF can actively enrich in tumor sites and respond to the acidic tumor microenvironment to offload AZTF nanoparticles, which can consume intracellular ATP (iATP) content and simultaneously inhibit the ATP-adenosine axis to reduce the accumulation of adenosine, thereby alleviating adenosine-mediated immunosuppression and strikingly amplifying ICD effect. Importantly, the synergy of anti-PD-1 (αPD-1) with Bc@AZTF not only establishes a collaborative antitumor immune network to potentiate effective tumoricidal immunity but also activates long-lasting immune memory effects to manage tumor recurrence and rechallenge, presenting a new paradigm for ICD treatment combined with adenosine metabolism.

Extract of Araçá-Boi and Its Major Phenolic Compound, Trans-Cinnamic Acid, Reduce Viability and Inhibit Migration of Human Metastatic Melanoma Cells

Cutaneous melanoma is an aggressive type of skin cancer that is recognized for its high metastatic potential and the challenges it presents in its treatment. There has been increasing interest in plant extracts and their potential applications in melanoma. The present study aimed to investigate the content of individual phenolic compounds in araçá-boi extract, evaluate their antioxidant activity, and explore their effects on cell viability, migration properties, oxidative stress levels, and protein expression in the human metastatic melanoma cell line SK-MEL-28. HPLC-DAD analysis identified 11 phenolic compounds in the araçá-boi extract. Trans-cinnamic acid was the main phenolic compound identified; therefore, it was used alone to verify its contribution to antitumor activities. SK-MEL-28 melanoma cells were treated for 24 h with different concentrations of araçá-boi extract and trans-cinnamic acid (200, 400, 600, 800, and 1600 µg/mL). Both the araçá-boi extract and trans-cinnamic acid reduced cell viability, cell migration, and oxidative stress in melanoma cells. Additionally, they modulate proteins involved in apoptosis and inflammation. These findings suggest the therapeutic potential of araçá-boi extract and its phenolic compounds in the context of melanoma, especially in strategies focused on preventing metastasis. Additional studies, such as the analysis of specific signaling pathways, would be valuable in confirming and expanding these observations.

Golgi apparatus targeted therapy in cancer: Are we there yet?

Membrane trafficking within the Golgi apparatus plays a pivotal role in the intracellular transportation of lipids and proteins. Dysregulation of this process can give rise to various pathological manifestations, including cancer. Exploiting Golgi defects, cancer cells capitalise on aberrant membrane trafficking to facilitate signal transduction, proliferation, invasion, immune modulation, angiogenesis, and metastasis. Despite the identification of several molecular signalling pathways associated with Golgi abnormalities, there remains a lack of approved drugs specifically targeting cancer cells through the manipulation of the Golgi apparatus. In the initial section of this comprehensive review, the focus is directed towards delineating the abnormal Golgi genes and proteins implicated in carcinogenesis. Subsequently, a thorough examination is conducted on the impact of these variations on Golgi function, encompassing aspects such as vesicular trafficking, glycosylation, autophagy, oxidative mechanisms, and pH alterations. Lastly, the review provides a current update on promising Golgi apparatus-targeted inhibitors undergoing preclinical and/or clinical trials, offering insights into their potential as therapeutic interventions. Significantly more effort is required to advance these potential inhibitors to benefit patients in clinical settings.

Oxidative stress, defective proteostasis and immunometabolic complications in critically ill patients

Oxidative stress (OS) develops in critically ill patients as a metabolic consequence of the immunoinflammatory and degenerative processes of the tissues. These induce increased and/or dysregulated fluxes of reactive species enhancing their pro-oxidant activity and toxicity. At the same time, OS sustains its own inflammatory and immunometabolic pathogenesis, leading to a pervasive and vitious cycle of events that contribute to defective immunity, organ dysfunction and poor prognosis. Protein damage is a key player of these OS effects; it generates increased levels of protein oxidation products and misfolded proteins in both the cellular and extracellular environment, and contributes to forms DAMPs and other proteinaceous material to be removed by endocytosis and proteostasis processes of different cell types, as endothelial cells, tissue resident monocytes-macrophages and peripheral immune cells. An excess of OS and protein damage in critical illness can overwhelm such cellular processes ultimately interfering with systemic proteostasis, and consequently with innate immunity and cell death pathways of the tissues thus sustaining organ dysfunction mechanisms. Extracorporeal therapies based on biocompatible/bioactive membranes and new adsorption techniques may hold some potential in reducing the impact of OS on the defective proteostasis of patients with critical illness. These can help neutralizing reactive and toxic species, also removing solutes in a wide spectrum of molecular weights thus improving proteostasis and its immunometabolic corelates. Pharmacological therapy is also moving steps forward which could help to enhance the efficacy of extracorporeal treatments. This narrative review article explores the aspects behind the origin and pathogenic role of OS in intensive care and critically ill patients, with a focus on protein damage as a cause of impaired systemic proteostasis and immune dysfunction in critical illness.

Design and synthesis of visible light-activatable photocaged peroxides for optical control of ROS-mediated cellular signaling

We designed and synthesized two novel photocaged peroxide compounds, N5TBHP and N6TBHP, featuring nitrogen-containing fused ring coumarin skeletons. Notably, a tetrahydroquinoline fused coumarin derivative, N6TBHP demonstrated significantly higher photocleavage efficiency under visible light at 455 nm compared to N5TBHP, which contains an indoline fused coumarin. This process effectively releases the oxidative stress inducer tert-butylhydroperoxide (TBHP). Additionally, N6TBHP exhibits high resistance to glutathione (GSH), and its UV spectral analysis suggests enhanced intracellular stability due to reduced reactivity with GSH through self-assembly. Furthermore, N6TBHP can release an optimal amount of TBHP into cells under visible light irradiation with minimal cell damage. These properties position N6TBHP as a promising tool for advancing research in intracellular redox signaling.

Nanorepair medicine for treatment of organ injury

Organ injuries, such as acute kidney injury, ischemic stroke, and spinal cord injury, often result in complications that can be life-threatening or even fatal. Recently, many nanomaterials have emerged as promising agents for repairing various organ injuries. In this review, we present the important developments in the field of nanomaterial-based repair medicine, herein referred to as 'nanorepair medicine'. We first introduce the disease characteristics associated with different types of organ injuries and highlight key examples of relevant nanorepair medicine. We then provide a summary of existing strategies in nanorepair medicine, including organ-targeting methodologies and potential countermeasures against exogenous and endogenous pathologic risk factors. Finally, we offer our perspectives on current challenges and future expectations for the advancement of nanomedicine designed for organ injury repair.

Superoxide signal orchestrates tetrathiomolybdate-induced longevity via ARGK-1 in Caenorhabditis elegans

PURPOSE

While reactive oxygen species (ROS) have been identified as key redox signaling agents contributing to aging process, which and how specific oxidants trigger healthy longevity remain unclear. This paper aimed to explore the precise role and signaling mechanism of superoxide (O2•-) in health and longevity.

METHODS

A tool for precise regulation of O2•- levels in vivo was developed based on the inhibition of superoxide dismutase 1 (SOD1) by tetrathiomolybdate (TM) in Caenorhabditis elegans (C. elegans). Then, we examined the effects of TM on lifespan, reproduction, lipofuscin accumulation, mobility, and stress resistance. Finally, the signaling mechanism for longevity induced by TM-O2•- was screened by transcriptome analysis and tested in sod-1 and argk-1 RNAi strains, sod-2, sod-3, and daf-16 mutants.

RESULTS

TM promoted longevity in C. elegans with a concomitant extension of healthy lifespan as indicated by increasing fertility and mobility and reducing lipofuscin accumulation, as well as enhanced resistance to different abiotic stresses. Mechanically, TM could precisely regulate O2•- levels in nematodes via modulating SOD1 activity. An O2•- scavenger Mn(III)TBAP abolished TM-induced lifespan extension, while an O2•- generator paraquat at low concentration mimicked the life prolongation effects. The longevity in TM-treated worms was abolished by sod-1 RNAi but was not affected in sod-2 or sod-3 mutants. Further transcriptome analysis revealed arginine kinase ARGK-1 and its downstream insulin/insulin-like growth factor 1 signaling (IIS) as potential effectors for TM-O2•‾-induced longevity, and argk-1 RNAi or daf-16 mutant nullified the longevity.

CONCLUSIONS

These findings indicate that it is feasible to precisely control specific oxidant in vivo and O2•- orchestrates TM-induced health and longevity in C. elegans via ARGK-1-IIS axis.

Mechanism of Action of Green-Synthesized Silver Nanoparticle-Incorporated Dental Varnish Against Candida albicans

INTRODUCTION

 Candida albicans, a common fungal pathogen, is often associated with oral infections such as denture stomatitis. Dental varnishes, especially those incorporating antimicrobial agents, have shown promise in preventing C. albicans colonization. This study investigates the antifungal efficacy of a dental varnish incorporating green-synthesized silver nanoparticles (AgNPs) using Ocimum gratissimum and Ocimum tenuiflorum extracts.

MATERIALS AND METHODS

AgNPs were synthesized via a green synthesis method using Ocimum extracts. The AgNPs were then incorporated into a dental varnish. The antifungal efficacy of the AgNP-incorporated varnish was evaluated against C. albicans using various assays, including agar well diffusion, time-kill curve, protein leakage, and cytoplasmic leakage analyses.

RESULTS

The AgNP-incorporated dental varnish demonstrated significant antifungal activity against C. albicans. The agar well diffusion assay showed a dose-dependent increase in the zone of inhibition, with the highest concentration (100 µg/mL) achieving a zone of 23 mm. The time-kill curve assay indicated a concentration-dependent reduction in colony-forming units (CFU) of C. albicans, with the highest concentration resulting in a CFU reduction to below 103 within five hours. Both protein and cytoplasmic leakage analyses confirmed membrane disruption, showing increased optical density readings at higher concentrations of AgNPs.

DISCUSSION

The results suggest that the antifungal activity of the AgNP-incorporated dental varnish is mediated through multiple mechanisms, including membrane disruption, increased permeability leading to protein and cytoplasmic leakage, and possibly the generation of reactive oxygen species (ROS). The varnish's efficacy was comparable to that of commercial antifungal dental varnishes, highlighting its potential as a viable alternative in dental applications.

CONCLUSION

Green-synthesized AgNPs, when incorporated into dental varnish, exhibit potent antifungal activity against C. albicans. The study demonstrates that this approach can effectively disrupt fungal cells, suggesting its potential use in preventing and treating oral fungal infections. Future research should explore the in vivo efficacy, safety, and long-term stability of AgNPs in dental varnish formulations.

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.

NADPH oxidase 4 (NOX4) as a biomarker and therapeutic target in neurodegenerative diseases

Diseases like Alzheimer's and Parkinson's diseases are defined by inflammation and the damage neurons undergo due to oxidative stress. A primary reactive oxygen species contributor in the central nervous system, NADPH oxidase 4, is viewed as a potential therapeutic touchstone and indicative marker for these ailments. This in-depth review brings to light distinct features of NADPH oxidase 4, responsible for generating superoxide and hydrogen peroxide, emphasizing its pivotal role in activating glial cells, inciting inflammation, and disturbing neuronal functions. Significantly, malfunctioning astrocytes, forming the majority in the central nervous system, play a part in advancing neurodegenerative diseases, due to their reactive oxygen species and inflammatory factor secretion. Our study reveals that aiming at NADPH oxidase 4 within astrocytes could be a viable treatment pathway to reduce oxidative damage and halt neurodegenerative processes. Adjusting NADPH oxidase 4 activity might influence the neuroinflammatory cytokine levels, including myeloperoxidase and osteopontin, offering better prospects for conditions like Alzheimer's disease and Parkinson's disease. This review sheds light on the role of NADPH oxidase 4 in neural degeneration, emphasizing its drug target potential, and paving the path for novel treatment approaches to combat these severe conditions.

Ferroptosis in health and disease

Ferroptosis is a pervasive non-apoptotic form of cell death highly relevant in various degenerative diseases and malignancies. The hallmark of ferroptosis is uncontrolled and overwhelming peroxidation of polyunsaturated fatty acids contained in membrane phospholipids, which eventually leads to rupture of the plasma membrane. Ferroptosis is unique in that it is essentially a spontaneous, uncatalyzed chemical process based on perturbed iron and redox homeostasis contributing to the cell death process, but that it is nonetheless modulated by many metabolic nodes that impinge on the cells' susceptibility to ferroptosis. Among the various nodes affecting ferroptosis sensitivity, several have emerged as promising candidates for pharmacological intervention, rendering ferroptosis-related proteins attractive targets for the treatment of numerous currently incurable diseases. Herein, the current members of a Germany-wide research consortium focusing on ferroptosis research, as well as key external experts in ferroptosis who have made seminal contributions to this rapidly growing and exciting field of research, have gathered to provide a comprehensive, state-of-the-art review on ferroptosis. Specific topics include: basic mechanisms, in vivo relevance, specialized methodologies, chemical and pharmacological tools, and the potential contribution of ferroptosis to disease etiopathology and progression. We hope that this article will not only provide established scientists and newcomers to the field with an overview of the multiple facets of ferroptosis, but also encourage additional efforts to characterize further molecular pathways modulating ferroptosis, with the ultimate goal to develop novel pharmacotherapies to tackle the various diseases associated with - or caused by - ferroptosis.

Revisiting reactive oxygen species production in hypoxia

Cellular responses to hypoxia are crucial in various physiological and pathophysiological contexts and have thus been extensively studied. This has led to a comprehensive understanding of the transcriptional response to hypoxia, which is regulated by hypoxia-inducible factors (HIFs). However, the detailed molecular mechanisms of HIF regulation in hypoxia remain incompletely understood. In particular, there is controversy surrounding the production of mitochondrial reactive oxygen species (ROS) in hypoxia and how this affects the stabilization and activity of HIFs. This review examines this controversy and attempts to shed light on its origin. We discuss the role of physioxia versus normoxia as baseline conditions that can affect the subsequent cellular response to hypoxia and highlight the paucity of data on pericellular oxygen levels in most experiments, leading to variable levels of hypoxia that might progress to anoxia over time. We analyze the different outcomes reported in isolated mitochondria, versus intact cells or whole organisms, and evaluate the reliability of various ROS-detecting tools. Finally, we examine the cell-type and context specificity of oxygen's various effects. We conclude that while recent evidence suggests that the effect of hypoxia on ROS production is highly dependent on the cell type and the duration of exposure, efforts should be made to conduct experiments under carefully controlled, physiological microenvironmental conditions in order to rule out potential artifacts and improve reproducibility in research.

Hydrogen regulated pyroptosis through NLRP3-GSDMD pathway to improve airway mucosal oxidative stress injury induced by endotracheal tube cuff compression

The cuff of endotracheal tube (ETT) is an indispensable device for establishing an artificial airway, yet cuff-induced compression often causes damage to the airway mucosa. The mechanism of this damage involves mucosal compression ischemia and the oxidative stress injury following reperfusion. Currently, there is a lack of effective strategies to protect the mucosa. Hydrogen, as a natural antioxidant, has demonstrated significant potential in the prevention and treatment of oxidative stress injuries. This study aimed to determine the protective effects of hydrogen on compressed airway mucosa. We found that the damage to the airway mucosa caused by ETT cuff compression was associated with oxidative stress-induced pyroptosis of airway epithelial cells. Inhalation of hydrogen effectively reduced the levels of reactive oxygen species, significantly ameliorating changes in epithelial cell pyroptosis, and this protective effect is linked to the inhibition of the NLRP3-GSDMD pathway. Further cellular studies, involving knockdown and overexpression of NLRP3, clarified that hydrogen exerts its protective effects on the airway mucosa by inhibiting epithelial cell pyroptosis. Additionally, we observed that using hydrogen-rich saline to inflate the ETT cuff in patients under general anesthesia significantly reduced postoperative sore throat. This study confirms that hydrogen effectively enhances tolerance of airway mucosa to oxidative stress injuries, offering a potential preventive and therapeutic strategy for protecting the airway mucosa in patients undergoing endotracheal intubation.

Ex Tenebris Lux: Illuminating Reactive Oxygen and Nitrogen Species with Small Molecule Probes

Reactive oxygen and nitrogen species are small reactive molecules derived from elements in the air─oxygen and nitrogen. They are produced in biological systems to mediate fundamental aspects of cellular signaling but must be very tightly balanced to prevent indiscriminate damage to biological molecules. Small molecule probes can transmute the specific nature of each reactive oxygen and nitrogen species into an observable luminescent signal (or even an acoustic wave) to offer sensitive and selective imaging in living cells and whole animals. This review focuses specifically on small molecule probes for superoxide, hydrogen peroxide, hypochlorite, nitric oxide, and peroxynitrite that provide a luminescent or photoacoustic signal. Important background information on general photophysical phenomena, common probe designs, mechanisms, and imaging modalities will be provided, and then, probes for each analyte will be thoroughly evaluated. A discussion of the successes of the field will be presented, followed by recommendations for improvement and a future outlook of emerging trends. Our objectives are to provide an informative, useful, and thorough field guide to small molecule probes for reactive oxygen and nitrogen species as well as important context to compare the ecosystem of chemistries and molecular scaffolds that has manifested within the field.

Crosstalk between ROS-inflammatory gene expression axis in the progression of lung disorders

A significant number of deaths and disabilities worldwide are brought on by inflammatory lung diseases. Many inflammatory lung disorders, including chronic respiratory emphysema, resistant asthma, resistance to steroids, and coronavirus-infected lung infections, have severe variants for which there are no viable treatments; as a result, new treatment alternatives are needed. Here, we emphasize how oxidative imbalance contributes to the emergence of provocative lung problems that are challenging to treat. Endogenic antioxidant systems are not enough to avert free radical-mediated damage due to the induced overproduction of ROS. Pro-inflammatory mediators are then produced due to intracellular signaling events, which can harm the tissue and worsen the inflammatory response. Overproduction of ROS causes oxidative stress, which causes lung damage and various disease conditions. Invasive microorganisms or hazardous substances that are inhaled repeatedly can cause an excessive amount of ROS to be produced. By starting signal transduction pathways, increased ROS generation during inflammation may cause recurrent DNA damage and apoptosis and activate proto-oncogenes. This review provides information about new targets for conducting research in related domains or target factors to prevent, control, or treat such inflammatory oxidative stress-induced inflammatory lung disorders.

Donor-Acceptor Type Supra-Carbon-Dots with Long Lifetime Photogenerated Radicals Boosting Tumor Photodynamic Therapy

Carbon dots (CDs) have gained significant interest because of their potential in biomedical applications. Nevertheless, developing CDs with efficient photoinduced charge separation for tumor photodynamic therapy (PDT) remains a challenge. This study presents a novel class of supra-carbon-dots (supra-CDs) developed by fusing red emissive CDs with 2,3-dicyanohydroquinone (DCHQ) via post-solvothermal treatment. In supra-CDs, the core, acting as electron donors, is formed by assembled CDs with substantial sp2 domains, the fused interface originating from DCHQ with electron-withdrawing groups functions as the electron acceptor. This configuration creates the unique donor-acceptor nanostructure. Upon white light irradiation, the excited electrons from the assembled CDs were transferred to the electron-withdrawing interface, whereas the photogenerated holes were retained within the assembled CDs as radicals, leading to effective photoinduced charge separation. The separated photogenerated electrons then react with oxygen to generate superoxide radicals. Simultaneously, the photogenerated holes undergo oxidation of crucial cellular substrates. This dual action underscores the exceptional cell-killing efficacy of supra-CDs. Moreover, the increased particle sizes (~20 nm) ensure supra-CDs to exhibit a notable capacity for tumor accumulation via the improved permeability and retention effect, thereby achieving satisfactory anti-tumor PDT efficacy in a mouse subcutaneous tumor model.

The Role of Oxidative Stress in Hypomagnetic Field Effects

The geomagnetic field (GMF) is crucial for the survival and evolution of life on Earth. The weakening of the GMF, known as the hypomagnetic field (HMF), significantly affects various aspects of life on Earth. HMF has become a potential health risk for future deep space exploration. Oxidative stress is directly involved in the biological effects of HMF on animals or cells. Oxidative stress occurs when there is an imbalance favoring oxidants over antioxidants, resulting in cellular damage. Oxidative stress is a double-edged sword, depending on the degree of deviation from homeostasis. In this review, we summarize the important experimental findings from animal and cell studies on HMF exposure affecting intracellular reactive oxygen species (ROS), as well as the accompanying many physiological abnormalities, such as cognitive dysfunction, the imbalance of gut microbiota homeostasis, mood disorders, and osteoporosis. We discuss new insights into the molecular mechanisms underlying these HMF effects in the context of the signaling pathways related to ROS. Among them, mitochondria are considered to be the main organelles that respond to HMF-induced stress by regulating metabolism and ROS production in cells. In order to unravel the molecular mechanisms of HMF action, future studies need to consider the upstream and downstream pathways associated with ROS.

Multi-Enzyme Mimetic MoCu Dual-Atom Nanozyme Triggering Oxidative Stress Cascade Amplification for High-Efficiency Synergistic Cancer Therapy

Single-atom nanozymes (SAzymes) with ultrahigh atom utilization efficiency have been extensively applied in reactive oxygen species (ROS)-mediated cancer therapy. However, the high energy barriers of reaction intermediates on single-atom sites and the overexpressed antioxidants in the tumor microenvironment restrict the amplification of tumor oxidative stress, resulting in unsatisfactory therapeutic efficacy. Herein, we report a multi-enzyme mimetic MoCu dual-atom nanozyme (MoCu DAzyme) with various catalytic active sites, which exhibits peroxidase, oxidase, glutathione (GSH) oxidase, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase mimicking activities. Compared with Mo SAzyme, the introduction of Cu atoms, formation of dual-atom sites, and synergetic catalytic effects among various active sites enhance substrate adsorption and reduce the energy barrier, thereby endowing MoCu DAzyme with stronger catalytic activities. Benefiting from the above enzyme-like activities, MoCu DAzyme can not only generate multiple ROS, but also deplete GSH and block its regeneration to trigger the cascade amplification of oxidative stress. Additionally, the strong optical absorption in the near-infrared II bio-window endows MoCu DAzyme with remarkable photothermal conversion performance. Consequently, MoCu DAzyme achieves high-efficiency synergistic cancer treatment incorporating collaborative catalytic therapy and photothermal therapy. This work will advance the therapeutic applications of DAzymes and provide valuable insights for nanocatalytic cancer therapy.

Structurally Oriented Carbon Dots as ROS Nanomodulators for Dynamic Chronic Inflammation and Infection Elimination

The selective elimination of cytotoxic ROS while retaining essential ones is pivotal in the management of chronic inflammation. Co-occurring bacterial infection further complicates the conditions, necessitating precision and an efficacious treatment strategy. Herein, the dynamic ROS nanomodulators are rationally constructed through regulating the surface states of herbal carbon dots (CDs) for on-demand inflammation or infection elimination. The phenolic OH containing CDs derived from honeysuckle (HOCD) and dandelion (DACD) demonstrated appropriate redox potentials, ensuring their ability to scavenge cytotoxic ROS such as ·OH and ONOO-, while invalidity toward essential ones such as O2·-, H2O2, and NO. This enables efficient treatment of chronic inflammation without affecting essential ROS signal pathways. The surface C-N/C═N of CDs derived from taxus leaves (TACD) and DACD renders them with suitable band structures, facilitating absorption in the red region and efficient generation of O2·- upon light irradiation for sterilization. Specifically, the facilely prepared DACD demonstrates fascinating dynamic ROS modulating ability, making it highly suitable for addressing concurrent chronic inflammation and infection, such as diabetic wound infection. This dynamic ROS regulation strategy facilitates the realization of the precise and efficient treatment of chronic inflammation and infection with minimal side effects, holding immense potential for clinical practice.

Mitochondrial complex III-derived ROS amplify immunometabolic changes in astrocytes and promote dementia pathology

Neurodegenerative disorders alter mitochondrial functions, including the production of reactive oxygen species (ROS). Mitochondrial complex III (CIII) generates ROS implicated in redox signaling, but its triggers, targets, and disease relevance are not clear. Using site-selective suppressors and genetic manipulations together with mitochondrial ROS imaging and multiomic profiling, we found that CIII is the dominant source of ROS production in astrocytes exposed to neuropathology-related stimuli. Astrocytic CIII-ROS production was dependent on nuclear factor-κB (NF-κB) and the mitochondrial sodium-calcium exchanger (NCLX) and caused oxidation of select cysteines within immune and metabolism-associated proteins linked to neurological disease. CIII-ROS amplified metabolomic and pathology-associated transcriptional changes in astrocytes, with STAT3 activity as a major mediator, and facilitated neuronal toxicity in a non-cell-autonomous manner. As proof-of-concept, suppression of CIII-ROS in mice decreased dementia-linked tauopathy and neuroimmune cascades and extended lifespan. Our findings establish CIII-ROS as an important immunometabolic signal transducer and tractable therapeutic target in neurodegenerative disease.

Visualizing hydrogen peroxide and nitric oxide dynamics in endothelial cells using multispectral imaging under controlled oxygen conditions

The complex interplay between hydrogen peroxide (H2O2) and nitric oxide (NO) in endothelial cells presents challenges due to technical limitations in simultaneous measurement, hindering the elucidation of their direct relationship. Previous studies have yielded conflicting findings regarding the impact of H2O2 on NO production. To address this problem, we employed genetically encoded biosensors, HyPer7 for H2O2 and geNOps for NO, allowing simultaneous imaging in single endothelial cells. Optimization strategies were implemented to enhance biosensor performance, including camera binning, temperature regulation, and environmental adjustments to mimic physiological normoxia. Our results demonstrate that under ambient oxygen conditions, H2O2 exhibited no significant influence on NO production. Subsequent exploration under physiological normoxia (5 kPa O2) revealed distinct oxidative stress levels characterized by reduced basal HyPer7 signals, enhanced H2O2 scavenging kinetics, and altered responses to pharmacological treatment. Investigation of the relationship between H2O2 and NO under varying oxygen conditions revealed a lack of NO response to H2O2 under hyperoxia (18 kPa O2) but a modest NO response under physiological normoxia (5 kPa O2). Importantly, the NO response was attenuated by l-NAME, suggesting activation of eNOS by endogenous H2O2 generation upon auranofin treatment. Our study highlights the intricate interplay between H2O2 and NO within the endothelial EA.hy926 cell line, emphasizing the necessity for additional research within physiological contexts due to differential response observed under physiological normoxia (5 kPa O2). This further investigation is essential for a comprehensive understanding of the H2O2 and NO signaling considering the physiological effects of ambient O2 levels involved.

Evidence-based sports supplements: A redox analysis

Despite the overwhelming number of sports supplements on the market, only seven are currently recognized as effective. Biological functions are largely regulated through redox reactions, yet no comprehensive analysis of the redox properties of these supplements has been compiled. Here, we analyze the redox characteristics of these seven supplements: bicarbonates, beta-alanine, caffeine, creatine, nitrates, carbohydrates, and proteins. Our findings suggest that all sports supplements exhibit some degree of redox activity. However, the precise physiological implications of these redox properties remain unclear. Future research, employing unconventional perspectives and methodologies, will reveal new redox pixels of the exercise physiology and sports nutrition picture.

Exploring the puzzle of reactive oxygen species acting on root hair cells

Reactive oxygen species (ROS) are essential signaling molecules that enable cells to respond rapidly to a range of stimuli. The ability of plants to recognize various stressors, incorporate a variety of environmental inputs, and initiate stress-response networks depends on ROS. Plants develop resilience and defensive systems as a result of these processes. Root hairs are central components of root biology since they increase the surface area of the root, anchor it in the soil, increase its ability to absorb water and nutrients, and foster interactions between microorganisms. In this review, we specifically focused on root hair cells and we highlighted the identification of ROS receptors, important new regulatory hubs that connect ROS production, transport, and signaling in the context of two hormonal pathways (auxin and ethylene) and under low temperature environmental input related to nutrients. As ROS play a crucial role in regulating cell elongation rates, root hairs are rapidly gaining traction as a very valuable single plant cell model for investigating ROS homeostasis and signaling. These promising findings might soon facilitate the development of plants and roots that are more resilient to environmental stressors.

Mechanism of Reactive Oxygen Species-Guided Immune Responses in Gouty Arthritis and Potential Therapeutic Targets

Gouty arthritis (GA) is an inflammatory disease caused by monosodium urate (MSU) crystals deposited in the joint tissues causing severe pain. The disease can recur frequently and tends to form tophus in the joints. Current therapeutic drugs for the acute phase of GA have many side effects and limitations, are unable to prevent recurrent GA attacks and tophus formation, and overall efficacy is unsatisfactory. Therefore, we need to advance research on the microscopic mechanism of GA and seek safer and more effective drugs through relevant targets to block the GA disease process. Current research shows that the pathogenesis of GA is closely related to NLRP3 inflammation, oxidative stress, MAPK, NET, autophagy, and Ferroptosis. However, after synthesizing and sorting out the above mechanisms, it is found that the presence of ROS is throughout almost the entire spectrum of micro-mechanisms of the gout disease process, which combines multiple immune responses to form a large network diagram of complex and tight connections involved in the GA disease process. Current studies have shown that inflammation, oxidative stress, cell necrosis, and pathological signs of GA in GA joint tissues can be effectively suppressed by modulating ROS network-related targets. In this article, on the one hand, we investigated the generative mechanism of ROS network generation and its association with GA. On the other hand, we explored the potential of related targets for the treatment of gout and the prevention of tophus formation, which can provide effective reference ideas for the development of highly effective drugs for the treatment of GA.

NOX2-TRPM2 coupling promotes Zn2+ inhibition of complex III to exacerbate ROS production in a cellular model of Parkinson's disease

Reactive oxygen species (ROS) serve vital physiological functions, but aberrant ROS production contributes to numerous diseases. Unfortunately, therapeutic progress targeting pathogenic ROS has been hindered by the limited understanding of whether the mechanisms driving pathogenic ROS differ from those governing physiological ROS generation. To address this knowledge gap, we utilised a cellular model of Parkinson's disease (PD), as an exemplar of ROS-associated diseases. We exposed SH-SY5Y neuroblastoma cells to the PD-toxin, MPP+ (1-methyl-4-phenylpyridinium) and studied ROS upregulation leading to cell death, the primary cause of PD. We demonstrate: (1) MPP+ stimulates ROS production by raising cytoplasmic Ca2+ levels, rather than acting directly on mitochondria. (2) To raise the Ca2+, MPP+ co-stimulates NADPH oxidase-2 (NOX2) and the Transient Receptor Potential Melastatin2 (TRPM2) channel that form a positive feedback loop to support each other's function. (3) Ca2+ exacerbates mitochondrial ROS (mtROS) production not directly, but via Zn2+. (4) Zn2+ promotes electron escape from respiratory complexes, predominantly from complex III, to generate mtROS. These conclusions are drawn from data, wherein inhibition of TRPM2 and NOX2, chelation of Ca2+ and Zn2+, and prevention of electron escape from complexes -all abolished the ability of MPP+ to induce mtROS production and the associated cell death. Furthermore, calcium ionophore mimicked the effects of MPP+, while Zn2+ ionophore replicated the effects of both MPP+ and Ca2+. Thus, we unveil a previously unrecognized signalling circuit involving NOX2, TRPM2, Ca2+, Zn2+, and complex III that drives cytotoxic ROS production. This circuit lies dormant in healthy cells but is triggered by pathogenic insults and could therefore represent a safe therapeutic target for PD and other ROS-linked diseases.

Antioxidant Potential of Exosomes in Animal Nutrition

This review delves into the advantages of exosomes as novel antioxidants in animal nutrition and their potential for regulating oxidative stress. Although traditional nutritional approaches promote oxidative stress defense systems in mammalian animals, several issues remain to be solved, such as low bioavailability, targeted tissue efficiency, and high-dose by-effect. As an important candidate offering regulation opportunities concerned with cellular communication, disease prevention, and physiology regulation in multiple biological systems, the potential of exosomes in mediating redox status in biological systems has not been well described. A previously reported relationship between redox system regulation and circulating exosomes suggested exosomes as a fundamental candidate for both a regulator and biomarker for a redox system. Herein, we review the effects of oxidative stress on exosomes in animals and the potential application of exosomes as antioxidants in animal nutrition. Then, we highlight the advantages of exosomes as redox regulators due to their higher bioavailability and physiological heterogeneity-targeted properties, providing a theoretical foundation and feed industry application. Therefore, exosomes have shown great potential as novel antioxidants in the field of animal nutrition. They can overcome the limitations of traditional antioxidants in terms of dosage and side effects, which will provide unprecedented opportunities in nutritional management and disease prevention, and may become a major breakthrough in the field of animal nutrition.

Mitochondria in Retinal Ganglion Cells: Unraveling the Metabolic Nexus and Oxidative Stress

This review explored the role of mitochondria in retinal ganglion cells (RGCs), which are essential for visual processing. Mitochondrial dysfunction is a key factor in the pathogenesis of various vision-related disorders, including glaucoma, hereditary optic neuropathy, and age-related macular degeneration. This review highlighted the critical role of mitochondria in RGCs, which provide metabolic support, regulate cellular health, and respond to cellular stress while also producing reactive oxygen species (ROS) that can damage cellular components. Maintaining mitochondrial function is essential for meeting RGCs' high metabolic demands and ensuring redox homeostasis, which is crucial for their proper function and visual health. Oxidative stress, exacerbated by factors like elevated intraocular pressure and environmental factors, contributes to diseases such as glaucoma and age-related vision loss by triggering cellular damage pathways. Strategies targeting mitochondrial function or bolstering antioxidant defenses include mitochondrial-based therapies, gene therapies, and mitochondrial transplantation. These advances can offer potential strategies for addressing mitochondrial dysfunction in the retina, with implications that extend beyond ocular diseases.

Stanniocalcin 2 governs cancer cell adaptation to nutrient insufficiency through alleviation of oxidative stress

Solid tumours often endure nutrient insufficiency during progression. How tumour cells adapt to temporal and spatial nutrient insufficiency remains unclear. We previously identified STC2 as one of the most upregulated genes in cells exposed to nutrient insufficiency by transcriptome screening, indicating the potential of STC2 in cellular adaptation to nutrient insufficiency. However, the molecular mechanisms underlying STC2 induction by nutrient insufficiency and subsequent adaptation remain elusive. Here, we report that STC2 protein is dramatically increased and secreted into the culture media by Gln-/Glc- deprivation. STC2 promoter contains cis-elements that are activated by ATF4 and p65/RelA, two transcription factors activated by a variety of cellular stress. Biologically, STC2 induction and secretion promote cell survival but attenuate cell proliferation during nutrient insufficiency, thus switching the priority of cancer cells from proliferation to survival. Loss of STC2 impairs tumour growth by inducing both apoptosis and necrosis in mouse xenografts. Mechanistically, under nutrient insufficient conditions, cells have increased levels of reactive oxygen species (ROS), and lack of STC2 further elevates ROS levels that lead to increased apoptosis. RNA-Seq analyses reveal STC2 induction suppresses the expression of monoamine oxidase B (MAOB), a mitochondrial membrane enzyme that produces ROS. Moreover, a negative correlation between STC2 and MAOB levels is also identified in human tumour samples. Importantly, the administration of recombinant STC2 to the culture media effectively suppresses MAOB expression as well as apoptosis, suggesting STC2 functions in an autocrine/paracrine manner. Taken together, our findings indicate that nutrient insufficiency induces STC2 expression, which in turn governs the adaptation of cancer cells to nutrient insufficiency through the maintenance of redox homoeostasis, highlighting the potential of STC2 as a therapeutic target for cancer treatment.

Effect of cadmium and polystyrene nanoplastics on the growth, antioxidant content, ionome, and metabolism of dandelion seedlings

Cadmium is the most prevalent heavy metal pollutant in the environment and can be readily combined with micro/nanoplastics (M/NPs) to change their bioavailability. In the present study, we comprehensively investigated the effect of polystyrene (PS) NPs on dandelion plants grown under Cd stress. Cd exposure significantly inhibited the growth of dandelion seedlings, resulting in a decrease in seedling elongation from 26.47% to 28.83%, a reduction in biomass from 29.76% to 54.14%, and an exacerbation of lipid peroxidation and oxidative stress. The interaction between PS NPs and Cd resulted in the formation of larger aggregates, with the Cd bioavailability reduced by 12.56%. PS NPs affect ion absorption by regulating reactive oxygen production and increasing superoxide dismutase activity, thereby mitigating the adverse effects of Cd. PSCd aggregates induced significant changes in the metabolic profiles of dandelions, affecting various carbohydrates related to alcohols, organic acids, sugar metabolism, and bioactive components related to flavonoids and phenolic acids. Furthermore, based on a structural equation model, exposure to PSCd activated oxidative stress and nutrient absorption, thereby affecting plant growth and Cd accumulation. Overall, our study provides valuable insights into the effects of PS NPs on Cd bioavailability, accumulation, and plant growth, which are crucial for understanding the food safety of medicinal plants in a coexistence environment.

Neurodegenerative diseases and catechins: (-)-epigallocatechin-3-gallate is a modulator of chronic neuroinflammation and oxidative stress

Catechins, a class of phytochemicals found in various fruits and tea leaves, have garnered attention for their diverse health-promoting properties, including their potential in combating neurodegenerative diseases. Among these catechins, (-)-epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea, has emerged as a promising therapeutic agent due to its potent antioxidant and anti-inflammatory effects. Chronic neuroinflammation and oxidative stress are key pathological mechanisms in neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). EGCG has neuroprotective efficacy due to scavenging free radicals, reducing oxidative stress and attenuating neuroinflammatory processes. This review discusses the molecular mechanisms of EGCG's anti-oxidative stress and chronic neuroinflammation, emphasizing its effects on autoimmune responses, neuroimmune system interactions, and focusing on the related effects on AD and PD. By elucidating EGCG's mechanisms of action and its impact on neurodegenerative processes, this review underscores the potential of EGCG as a therapeutic intervention for AD, PD, and possibly other neurodegenerative diseases. Overall, EGCG emerges as a promising natural compound for combating chronic neuroinflammation and oxidative stress, offering novel avenues for neuroprotective strategies in the treatment of neurodegenerative disorders.

Controlling Pericellular Oxygen Tension in Cell Culture Reveals Distinct Breast Cancer Responses to Low Oxygen Tensions

In oxygen (O2)-controlled cell culture, an indispensable tool in biological research, it is presumed that the incubator setpoint equals the O2 tension experienced by cells (i.e., pericellular O2). However, it is discovered that physioxic (5% O2) and hypoxic (1% O2) setpoints regularly induce anoxic (0% O2) pericellular tensions in both adherent and suspension cell cultures. Electron transport chain inhibition ablates this effect, indicating that cellular O2 consumption is the driving factor. RNA-seq analysis revealed that primary human hepatocytes cultured in physioxia experience ischemia-reperfusion injury due to cellular O2 consumption. A reaction-diffusion model is developed to predict pericellular O2 tension a priori, demonstrating that the effect of cellular O2 consumption has the greatest impact in smaller volume culture vessels. By controlling pericellular O2 tension in cell culture, it is found that hypoxia vs. anoxia induce distinct breast cancer transcriptomic and translational responses, including modulation of the hypoxia-inducible factor (HIF) pathway and metabolic reprogramming. Collectively, these findings indicate that breast cancer cells respond non-monotonically to low O2, suggesting that anoxic cell culture is not suitable for modeling hypoxia. Furthermore, it is shown that controlling atmospheric O2 tension in cell culture incubators is insufficient to regulate O2 in cell culture, thus introducing the concept of pericellular O2-controlled cell culture.

How are hydrogen peroxide messages relayed to affect cell signalling?

H2O2 signals trigger adaptive responses affecting cell division, differentiation, migration, and survival. These signals are transduced by selective oxidation of cysteines on specific target proteins, with redox-sensitive cysteines now identified in many proteins, including both kinases and phosphatases. Assessing the contribution of these oxidation events to cell signalling presents several challenges including understanding how and when the selective oxidation of specific proteins takes place in vivo. In recent years, a combination of biochemical, structural, genetic, and computational approaches in fungi, plants, and animals have revealed different ways in which thiol peroxidases (peroxiredoxins) are bypassed or utilised in relaying these signals. Together, these mechanisms provide a conceptual framework for selectively oxidising proteins that will further advance understanding of how redox modifications contribute to health and disease.

The redox code of plants

Central metabolism is organised through high-flux, Nicotinamide Adenine Dinucleotide (NAD+/NADH) and NADP+/NADPH systems operating at near equilibrium. As oxygen is indispensable for aerobic organisms, these systems are also linked to the levels of reactive oxygen species, such as H2O2, and through H2O2 to the regulation of macromolecular structures and activities, via kinetically controlled sulphur switches in the redox proteome. Dynamic changes in H2O2 production, scavenging and transport, associated with development, growth and responses to the environment are, therefore, linked to the redox state of the cell and regulate cellular function. These basic principles form the 'redox code' of cells and were first defined by D. P. Jones and H. Sies in 2015. Here, we apply these principles to plants in which recent studies have shown that they can also explain cell-to-cell and even plant-to-plant signalling processes. The redox code is, therefore, an integral part of biological systems and can be used to explain multiple processes in plants at the subcellular, cellular, tissue, whole organism and perhaps even community and ecosystem levels. As the environmental conditions on our planet are worsening due to global warming, climate change and increased pollution levels, new studies are needed applying the redox code of plants to these changes.

Post-translational modifications in kidney diseases and associated cardiovascular risk

Patients with chronic kidney disease (CKD) are at an increased cardiovascular risk compared with the general population, which is driven, at least in part, by mechanisms that are uniquely associated with kidney disease. In CKD, increased levels of oxidative stress and uraemic retention solutes, including urea and advanced glycation end products, enhance non-enzymatic post-translational modification events, such as protein oxidation, glycation, carbamylation and guanidinylation. Alterations in enzymatic post-translational modifications such as glycosylation, ubiquitination, acetylation and methylation are also detected in CKD. Post-translational modifications can alter the structure and function of proteins and lipoprotein particles, thereby affecting cellular processes. In CKD, evidence suggests that post-translationally modified proteins can contribute to inflammation, oxidative stress and fibrosis, and induce vascular damage or prothrombotic effects, which might contribute to CKD progression and/or increase cardiovascular risk in patients with CKD. Consequently, post-translational protein modifications prevalent in CKD might be useful as diagnostic biomarkers and indicators of disease activity that could be used to guide and evaluate therapeutic interventions, in addition to providing potential novel therapeutic targets.

Targeting ROS in cancer: rationale and strategies

Reactive oxygen species (ROS) in biological systems are transient but essential molecules that are generated and eliminated by a complex set of delicately balanced molecular machineries. Disruption of redox homeostasis has been associated with various human diseases, especially cancer, in which increased ROS levels are thought to have a major role in tumour development and progression. As such, modulation of cellular redox status by targeting ROS and their regulatory machineries is considered a promising therapeutic strategy for cancer treatment. Recently, there has been major progress in this field, including the discovery of novel redox signalling pathways that affect the metabolism of tumour cells as well as immune cells in the tumour microenvironment, and the intriguing ROS regulation of biomolecular phase separation. Progress has also been made in exploring redox regulation in cancer stem cells, the role of ROS in determining cell fate and new anticancer agents that target ROS. This Review discusses these research developments and their implications for cancer therapy and drug discovery, as well as emerging concepts, paradoxes and future perspectives.