Hydrogen peroxide as a central redox signaling molecule in physiological oxidative stress: Oxidative eustress

MRI-responsive nanoprobes for visualizing hydrogen peroxide in diabetic liver injury

Diabetic liver injury has emerged as a significant complication associated with diabetes, warranting increased attention. The generation of hydrogen peroxide (H2O2) due to oxidative stress plays a critical role in the onset and progression of this condition. Despite this, there is a scarcity of probes capable of non-invasively, accurately, and reliably visualizing H2O2 levels in deep-seated liver in diabetes-induced liver injury. In this study, we introduce a novel H2O2-responsive magnetic probe (H2O2-RMP), designed for the sensitive imaging of H2O2 in the liver injury caused by diabetes. H2O2-RMP is synthesized through the co-precipitation of a H2O2-responsive amphiphilic polymer, manganese(III) porphyrin (Mn-porphyrin), and iron oxide nanoparticles. When exposed to H2O2, the released iron oxide nanoparticles aggregate, resulting in an increased T2-weighted MR signal intensity. H2O2-RMP not only demonstrates a wide dynamic response range (initial r2 = 9.87 mM-1s-1, Δr2 = 7.69 mM-1s-1), but also exhibits superior selectivity for H2O2 compared to other reactive oxygen species. Importantly, H2O2-RMP exhibits high sensitivity, with a detection limit for hydrogen peroxide as low as 0.56 μM. Moreover, H2O2-RMP has been effectively applied for real-time imaging of H2O2 levels in the livers of diabetic model mice with varying degrees of severity, highlighting its potential for visual diagnosis and monitoring the progression of diabetic liver injury.

A screen-printed microelectrode for detection of hydrogen peroxide in solid tumor in vivo

Hydrogen peroxide (H2O2), a crucial redox signaling molecule and neuromodulator, is closely associated with pathological processes, including cancer progression and neurodegenerative disorders. Current methods for in vivo H2O2 detection, such as fluorescence imaging and chemiluminescence, suffer from the limitation of spatial resolution and invasiveness, which makes it difficult to monitor oxidative stress gradients in deep-seated tumors. Therefore, this research developed an implantable triple-electrode biosensor fabricated via screen-printing technology based on carboxylated multi-walled carbon nanotubes (MWCNT) and Prussian blue (PB) nanocomposites. The biosensor presented dual linear detection ranges of 0.8-1126 μM (R2 = 0.9937) and 1286-3766 μM (R2 = 0.9939) with a 0.47 μM detection limit. It demonstrated a >95 % specificity compared with other interfering substances and maintained 93.2 % signal retention over 30 days. Particularly, in situ implantation in melanoma-bearing mice with one-week-growth-time solid tumors revealed the H2O2 levels 12- to 18-fold higher than in normal tissues, consistent with cancer-associated oxidative stress mechanisms. This platform addresses challenges such as rapid enzymatic degradation and microenvironmental complexity, enabling invasive profiling of H2O2 detection in solid tumors.

Salvianolic acid-A alleviates oxidative stress-induced osteoporosis

AIM

Cellular damage induced by oxidative stress contributes to systemic bone disorders leading to osteoporosis. Bone homeostasis regulates the balance between the functions of osteoblasts and osteoclasts. Osteoblast cells are responsible for bone formation and are very sensitive to oxidative stress. Polyphenolic compounds possess the ability to scavenge free radicals, thus reducing intracellular oxidative stress. Natural compounds such as salvianolic acid A (SAL-A) exhibit prominent antioxidant properties. However, its antioxidant role in bone homeostasis is poorly defined. In this study, we aimed to elucidate the potential role of SAL-A in protecting the osteoblasts from H2O2-induced oxidative stress.

MAIN METHODS

Rat osteoblast cells were treated with or without 500 μM H2O2 in the presence or absence of 5 μM and 10 μM of SAL-A. A series of assays such as cell viability by CCK-8 kit, detection of reactive oxygen species by dichlorodihydrofluorescein diacetate (DCFH-DA), mitochondrial membrane potential by JC-1 fluorescence, level of bone mineralization proteins osteocalcin, bone sialoprotein, and alkaline phosphatase by immunocytochemistry studies, were conducted.

KEY FINDINGS

SAL-A protected the rat osteoblast cells from H2O2-induced cytotoxicity by significantly attenuating free radical generation, thus improving cell viability. SAL-A treatment also significantly restored bone mineralization proteins, including osteocalcin, bone sialoprotein, and alkaline phosphatase, which were aggravated by H2O2-induced oxidative stress.

SIGNIFICANCE

The study results provide the role of SAL-A in protecting the osteoblasts from H2O2-induced oxidative stress in rat osteoblast cells by scavenging the free radicals, increasing the cell viability, mineralization, and differentiation of osteoblasts.

Borinic Acid-Based Fluorogenic Probes as an Alternative to the Amplex Red Assay for Real-Time H2O2 Monitoring in Live Cells

Hydrogen peroxide (H2O2) is a crucial reactive oxygen species (ROS) involved in regulating both physiological and pathological processes. Excessive H2O2 production can lead to oxidative stress, contributing to aging, cancer, and neurodegenerative diseases. In contrast to other ROS exhibiting short lifespans, H2O2 is relatively stable, and its spatial and temporal dynamics are central to understanding its pathophysiological role. Therefore, the development of fluorescent probes that are highly selective, sensitive, and capable of a rapid response is still required. To date, numerous fluorescent probes have been developed. Among them, boronic acid triggers have attracted considerable attention but often suffer from limited reactivity, preventing real-time H2O2 monitoring. To overcome this lack of reactivity, we report the design and synthesis of new borinic acid-based fluorogenic probes for H2O2 detection in cellular environments. These probes are based on a hemicyanine scaffold functionalized with the borinic acid trigger, which demonstrated superior kinetics compared to its boronic counterpart. These probes enable efficient real-time monitoring of H2O2 in cellular models, both extracellularly and intracellularly. The kinetics of these enzyme-free chemical probes matched that of the gold standard Amplex UltraRed/horseradish peroxidase (HRP) assay, representing a significant advancement in the field and offering a versatile and sensitive tool for studying H2O2-mediated cell signaling.

Metals, cardiovascular risk, and the interplay with oxidative stress: a mini-review

Oxidative stress plays a key role in the mechanisms underlying pathophysiological processes, such as inflammation, age-related degenerative phenomena, atherosclerosis, hypertension, cancer, diabetes mellitus, neurodegenerative diseases, xenobiotic toxicity, among others. It is generated by the production of free radicals, resulting from the oxidative metabolism of cells. Oxidative stress is an important defense against infections. It acts specifically as a vasodilator and helps modulate antioxidant mechanisms. However, the effects become harmful when its production increases or antioxidant mechanisms are excessively reduced. Toxic metals from environmental and occupational exposure are silent agents that induce oxidative stress. Metals such as mercury (Hg), aluminum (Al), cadmium (Cd), and lead (Pb) are known to be toxic to various organs and tissues in our body. The present mini-review focuses on the cardiovascular system, considering that the interplay between oxidative stress and toxic metals acting silently is involved in their harmful effects, especially on the etiopathogenesis of cardiovascular disorders. A brief review is also given regarding the mechanisms of modulation of redox homeostasis by organic mechanisms, pharmacological approaches that can act directly or indirectly as antioxidants, and food-derived compounds that appear to be effective inhibitors of oxidative stress, thus preventing the harmful effects of free radicals.

Nanorobot-Cell Communication via In Situ Generation of Biochemical Signals: Toward Regenerative Therapies

Achieving precise control of cellular processes drives possibilities for next-generation therapeutic approaches. However, existing technologies for influencing cell behavior primarily rely on specific drug delivery, limiting their ability to mimic natural cellular communication processes. In this work, we developed glucose-powered gold-silica (Au-SiO2) nanorobots that induce cell migration by generating steady-state hydrogen peroxide (H2O2) as a biochemical signaling molecule to mimic natural cellular communication with high spatial resolution. These nanorobots leverage the unique 2-in-1 catalytic activity of gold nanoparticles for glucose oxidation and H2O2 decomposition, allowing for precise control over the generation of steady-state H2O2 concentration and enhanced diffusion powered by glucose within the cellular microenvironment. We further demonstrated that at low dosages of nanorobots, the steady-state H2O2 generation promotes cell migration and proliferation, while higher dosages of nanorobots slow down cell proliferation. The proposed design of this biocompatible nanorobot is intended to enable communication with the environment and provide a noninvasive, biochemical command system for regulating cellular behavior. Additionally, we show proof of principle of a method by which nanorobots can augment wound healing and similar regenerative therapies.

The spatiotemporal heterogeneity of reactive oxygen species in the malignant transformation of viral hepatitis to hepatocellular carcinoma: a new insight

During the transformation of viral hepatitis into hepatocellular carcinoma (HCC), oxidative stress levels increase significantly, leading to tissue damage and chronic inflammation. HCC is characterized by spatiotemporal heterogeneity, which influences oxidative stress patterns, with reactive oxygen species (ROS) as the primary representative molecules. ROS serve not only as critical biomarkers of cancer but also as potential therapeutic targets for HCC, given that their increased levels can either promote or inhibit disease progression. In this review, we systematically examine the temporal heterogeneity of ROS, emphasizing its role in different stages of HCC progression caused by viral hepatitis and in influencing cell fate. We further explore ROS spatial heterogeneity at three levels: cellular, organelle, and biomolecular. Next, we comprehensively review clinical applications and potential therapies designed to selectively modulate ROS on the basis of its spatiotemporal heterogeneity. Finally, we discuss potential future applications of novel therapies that target ROS spatiotemporal heterogeneity to prevent and manage HCC onset and progression. In conclusion, this review enhances understanding of ROS in the progression of viral hepatitis to HCC and offers insights into developing new therapeutic targets and strategies centered on ROS heterogeneity.

Catalase in Unexpected Places: Revisiting H2O2 Detoxification Pathways in Stallion Spermatozoa

Oxidative stress plays a critical role in regulating sperm function, yet species-specific antioxidant mechanisms remain poorly understood. This study compared hydrogen peroxide (H2O2) tolerance in horse and human sperm and investigated the roles of catalase and glutathione peroxidase (GPx) in horses. A H2O2 dose-response assay (0-2000 µM) showed that horse sperm were significantly more resistant to oxidative damage, with an IC50 for progressive motility over 14-fold higher than that of human sperm (391.6 µM vs. 27.3 µM). Horse sperm also accumulated more intracellular H2O2 without loss of motility or viability. DNA damage assays (Halo and SCSA) revealed H2O2-induced fragmentation in human but not horse sperm. Enzyme inhibition experiments in horse sperm using 3-amino-1,2,4-triazole (catalase inhibitor) and (1S,3R)-RSL3 (GPx inhibitor) at 250 µM H2O2 showed that catalase inhibition severely impaired motility and increased intracellular H2O2 > 100-fold, while GPx inhibition had a milder effect (~5-fold increase). Immunocytochemistry localized catalase to the sperm head, particularly the post-acrosomal region, challenging the notion that sperm lack peroxisomes. The dependence of horse sperm on oxidative phosphorylation may drive the need for enhanced antioxidant defenses. These findings reveal species-specific oxidative stress adaptations and highlight catalase as a key antioxidant in equine sperm.

Vascular actions of Ang 1-7 and Ang 1-8 through EDRFs and EDHFs in non-diabetes and diabetes mellitus

The renin-angiotensin system (RAS) plays a pivotal role in regulating vascular homeostasis, while angiotensin 1-8 (Ang 1-8) traditionally dominates as a vasoconstrictor factor. However, the discovery of angiotensin 1-7 (Ang 1-7) and Ang 1-8 has revealed counter-regulatory mechanisms mediated through endothelial-derived relaxing factors (EDRFs) and endothelial-derived hyperpolarizing factors (EDHFs). This review delves into the vascular actions of Ang 1-7 and Ang 1-8 in both non-diabetes mellitus (non-DM) and diabetes mellitus (DM) conditions, highlighting their effects on vascular endothelial cell (VECs) function as well. In a non-DM vasculature context, Ang 1-8 demonstrate dual effect including vasoconstriction and vasodilation, respectively. Additionally, Ang 1-7 induces vasodilation upon nitric oxide (NO) production as a prominent EDRFs in distinct mechanisms. Further research elucidating the precise mechanisms underlying the vascular actions of Ang 1-7 and Ang 1-8 in DM will facilitate the development of tailored therapeutic interventions aimed at preserving vascular health and preventing cardiovascular complications.

Pathomechanistic Synergy Between Particulate Matter and Traffic Noise-Induced Cardiovascular Damage and the Classical Risk Factor Hypertension

Significance: In all modern urbanized and industrialized societies, noncommunicable diseases, such as cardiovascular disease (CVD), are becoming a more important cause of morbidity and mortality. Classical risk factors for CVDs, such as hypertension, are reinforced by behavioral risk factors, e.g., smoking and diet, and environmental risk factors, e.g., transportation noise and air pollution. Recent Advances: Both transportation noise and air pollution have individually been shown to increase the risk for CVD in large cohorts. Insights from animal studies have revealed pathophysiologic mechanisms by which these stressors influence the cardiovascular system. Noise primarily causes annoyance and sleep disturbance, promoting the release of stress hormones. Air pollution primarily damages the lung, where it causes local inflammation and an increase in oxidative stress, which can propagate to the circulation and remote organs. Critical Issues: Both noise and air pollution converge at the vascular level, where the inflammatory state and oxidative stress cause dysfunction in vascular signaling and promote atherosclerotic plaque formation and thrombosis. Both inflammation and oxidative stress are key aspects of traditional cardiovascular risk factors, such as arterial hypertension. The similarities among the mechanisms of environmental risk factor-induced CVD and hypertension indicate that a complex interplay between them can drive the onset and progression of CVDs, leading to synergistic health impacts. Future Directions: Our present overview of the negative effects of noise and air pollution on the cardiovascular system provides a mechanistic link to the traditional CVD risk factor, hypertension, which could be used to protect patients with preexisting CVD better. Antioxid. Redox Signal. 42, 827-847.

Impact of a high inspired oxygen fraction on oxidative stress in pediatric patients: reassuring results based on a randomized trial

High-concentration oxygen inhalation is the primary intervention to prevent perioperative hypoxemia. However, there are concerns that this may induce an imbalance in oxidation‒reduction processes, particularly in pediatric patients with compromised antioxidant defenses. This study aimed to evaluate the impact of varying intraoperative concentrations of oxygen inhalation on oxidative stress in children by analyzing plasma biomarkers, oxygenation indices, and the duration of surgery and oxygen inhalation. Forty-five children scheduled for laparoscopic pyeloplasty under general anesthesia were randomly assigned to three groups, each receiving different fractions of inspired oxygen during surgery: 30%, 50%, or 80%. The primary outcome was the plasma concentration of oxidative stress markers, and the other measurements included the surgical duration and duration of oxygen exposure. Thirty-five children completed the study, with 11 in the low group, 12 in the medium group and 12 in the high group. The levels of superoxide dismutase at immediately post-tracheal intubation, hydrogen peroxide at 1 hour post-intubation, and 8-isoprostane at immediately post-surgical procedure were significantly higher in the high group than in the low group. The S100B levels at immediately post-surgical procedure were higher than those at immediately post-tracheal intubation and 1 hour post-intubation within the low group. Therefore, we conclude that inhaling a high concentration of oxygen during laparoscopic pyeloplasty under general anesthesia, for a duration of less than 3 hours, does not significantly increase oxidative stress in pediatric patients. This study was registered at the Chinese Clinical Trial Registry (registration No. ChiCTR2400083143).

The two faces of coenzyme A in cellular biology

Coenzyme A (CoA) is an essential cofactor present in all living cells, which plays critical roles in diverse biochemical processes, including cellular metabolism, signal transduction, regulation of gene expression, and the antioxidant response. This review summarizes current knowledge on the role of CoA and its metabolically active thioesters in promoting cellular growth and proliferation (pro-growth) and discusses emerging research on CoA's antioxidant properties that enhance cell survival (pro-survival).

Defence Warriors: Exploring the crosstalk between polyamines and oxidative stress during microbial pathogenesis

Microbial infections have been a widely studied area of disease research since historical times, yet they are a cause of severe illness and deaths worldwide. Furthermore, infections by pathogens are not just restricted to humans; instead, a diverse range of hosts, including plants, livestock, marine organisms and fish, cause significant economic losses and pose threats to humans through their transmission in the food chain. It is now believed that both the pathogen and the host contribute to the outcomes of a disease pathology. Researchers have unravelled numerous aspects of host-pathogen interactions, offering valuable insights into the physiological, cellular and molecular processes and factors that contribute to the development of infectious diseases. Polyamines are key factors regulating cellular processes and human ageing and health. However, they are often overlooked in the context of host-pathogen interactions despite playing a dynamic role as a defence molecule from the perspective of the host as well as the pathogen. They form a complex network interacting with several molecules within the cell, with reactive oxygen species being a key component. This review presents a thorough overview of the current knowledge of polyamines and their intricate interactions with reactive oxygen species in the infection of multiple pathogens in diverse hosts. Interestingly, the review covers the interplay of the commensals and pathogen infection involving polyamines and reactive oxygen species, highlighting an unexplored area within this field. From a future perspective, the dynamic interplay of polyamines and oxidative stress in microbial pathogenesis is a fascinating area that widens the scope of developing therapeutic strategies to combat deadly infections.

Role of hyaluronate containing artificial tears in mitigating markers of dry eye disease using in vitro models

PURPOSE

Ocular surface discomfort and dry eye disease (DED) are the most common conditions addressed by ophthalmologists worldwide. Artificial tear substitutes are used as the first line of treatment management for DED patients. The present study was performed to understand the role of artificial tear formulation namely Soha Liquigel (0.18% sodium hyaluronate with trehalose) and Soha (0.1% sodium hyaluronate) for the treatment of DED in vitro . Human corneal epithelial (HCE) cells were used in adapted cell culture conditions which induce relevant cellular and molecular modifications thus mimicking the DED.

METHODS

Artificial tears containing either sodium hyaluronate (SH) (Soha 0.1%, Sun Pharma) or a combination of SH with trehalose (Soha Liquigel 0.18%, Sun Pharma) were compared with respective controls to analyze the effect on desiccation-induced stress or oxidative stress or hyperosmolarity induced stress on HCE cells. Cellular viability was evaluated using the trypan blue assay, while epithelial morphology was observed under light microscopy. Real-time polymerase chain reaction (RT-PCR) was utilized to analyze the transcriptional profile of a specific set of gene signatures, namely S100A7, FOS, SOD-2, COX2, TonEBP, IL6, MCP1, and IL10.

RESULTS

The response of HCE cells to desiccation stress (24 hr) was observed through alterations in their cellular morphology, which were subsequently restored by applying Soha Liquigel. Oxidative stress was induced using 100 nM of H 2 O 2 on HCE cells (short- 24 h and long-term 5 days) and measured using increased expression of S100A7, an oxidative stress-responsive gene. Oxidative-stressed HCE cells after treatment with Soha Liquigel showed reduced pro-oxidant gene and COX2 expression and elevated anti-oxidant genes, FOS, and SOD levels. HCE cells were subjected to +100mOsmol and +200mOsmol NaCl-containing media, inducing hyperosmolar stress that imitates the symptoms of DED. Further, these hyperosmolar stressed cells were treated with Soha Liquigel and Soha eye drops for 24 h and 5 days. Both eye drops rescued the cell morphology under hyperosmolar conditions in both short- and long-term treatments. Increased TonEBP levels confirm the osmotic stress in HCE cells. Reduction in IL6, MCP1, TonEBP, and elevated expression of IL10 in hyperosmotic stressed HCE cells treated with either of the artificial tears indicates their osmo-protection properties.

CONCLUSION

By using desiccation, oxidative, and hyperosmolar stress simulated in HCE cells in culture, we observed that SH-containing artificial tears provided bio-protection, osmo-protection, and anti-oxidant benefits that were further strengthened with SH and trehalose combination.

Redox Imbalance in Inflammation: The Interplay of Oxidative and Reductive Stress

Redox imbalance plays a pivotal role in the regulation of inflammation, influencing both the onset and progression of various inflammatory conditions. While the pro-inflammatory role of oxidative stress (OS) is well established, the impact of reductive stress (RS)-a condition marked by excessive reducing equivalents such as NADH, NADPH, and reduced glutathione (GSH)-remains underappreciated. This review offers a novel integrative perspective by analyzing how OS and RS act not merely in opposition, but as interconnected modulators of immune function. We explore the mechanisms through which OS activates inflammatory pathways, and how RS, when sustained, can paradoxically impair immune defense, alter redox-sensitive signaling, and contribute to disease progression. Emphasis is placed on the dynamic interplay between these redox extremes and their combined contribution to the pathogenesis of chronic inflammatory diseases, including autoimmune, cardiovascular, and neuroinflammatory disorders. Additionally, we evaluate therapeutic strategies that target redox homeostasis, arguing for a shift from antioxidant-centric treatments to approaches that consider the bidirectional nature of redox dysregulation. This framework may inform the development of more precise interventions for inflammation-related diseases.

Reactive oxygen species-dependent nanomedicine therapeutic modalities for gastric cancer

Reactive oxygen species (ROS) play a double-edged role in gastric cancer (GC). Higher levels of ROS in tumor cells compared to normal cells facilitate tumor progression. Once ROS concentrations rise rapidly to toxic levels, they cause GC cell death, which is instead beneficial for GC treatment. Based on these functions, nano-delivery systems taking the therapeutic advantages of ROS have been widely employed in tumor therapy in recent years, overcoming the drawbacks of conventional drug delivery techniques, such as non-specific systemic effects. In this review, the precise impacts of ROS on GC have been detailed, along with ROS-based nanomedicine therapeutic schemes. These strategies mainly focused on the use of excess ROS in the tumor microenvironment for controlled drug release and a substantial enhancement of ROS concentrations for tumor killing. The challenges and opportunities for the advancement of these anticancer therapies are also emphasized.

Catalase-encapsulated matrix metalloproteinase-9 responsive nanogels for modulation of inflammatory response and treatment of neutrophilic asthma

Asthma is a chronic disease with typical pathological features such as airflow limitation, airway inflammation and remodeling. Of these, neutrophilic asthma is considered to be the more severe and corticosteroid-resistant subtype of asthma. Increasing evidence suggests that patients with neutrophilic asthma often accompany with dysbiosis of the internal microbiota, where the increased abundance of non-typeable Haemophilus influenzae (NTHi) is closely related to the neutrophilic asthma phenotype. Furthermore, emerging evidence suggests that reactive oxygen species (ROS) are pivotal in the pathogenesis of neutrophilic asthma. In this study, matrix metalloproteinase-9 (MMP-9)-responsive, catalase-loaded nanogels (M-CAT-NGs) were synthesized, which was composed of MMP-9-sensitive peptide (VPMS), arginine-grafted chitosan and maleimide (CS-Arg-Mal), catalase (CAT), sodium citrate (SC) and ε-poly(L-lysine) (ε-PLL). The M-CAT-NGs showed potent antimicrobial effects and exerted excellent therapeutic effects in the presence of MMP-9 by causing VPMS rupture and responsive release of CAT. In vitro experiments revealed that M-CAT-NGs effectively inhibited the proliferation of NTHi, Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli), while also demonstrating the capacity to modulate the inflammatory response induced by lipopolysaccharide (LPS) and hydrogen peroxide (H2O2) stimulation. In vivo experiments demonstrated that nebulized inhalation of M-CAT-NGs was effective in reducing airway hyperresponsiveness (AHR), alleviating inflammation, downregulating the expression level of ROS in the lung tissues, thus enabling the effective management of neutrophilic asthma. Thus, the development of M-CAT-NGs has shown strong potential for the clinical management of neutrophilic asthma by modulating the inflammatory response.

A Novel Adamantane-Dioxetane-Based Chemiluminescent Probe for Highly Selective and Sensitive Bioimaging of Hydrogen Peroxide In Vitro and In Vivo

Hydrogen peroxide (H2O2) is an important intracellular reactive oxygen species that participates in a variety of life activities as a second messenger, especially as a pro-inflammation marker. Chemiluminescence is currently an ideal chemical tool for detecting biological substances, with the advantages of excellent signal-to-noise ratio and free autofluorescence interference, which is a cutting-edge science and technology for life sciences research. Herein, we report the design and evaluation of a novel chemiluminescent probe embedding a pentafluorobenzenesulfonyl ester group as a recognition moiety in a dioxetane skeleton. The results of imaging in living cells indicate that probe 4 (in 5 proposed probes) possesses high sensitivity, good selectivity, and the lowest limit of detection toward exogenous and endogenous H2O2 (LOD = 0.511 nM) compared with all the reported probes. It especially demonstrates excellent recognition performance in distinguishing between ONOO- and H2O2. Additionally, probe 4 shows low cytotoxicity and good biocompatibility, which performs highly specific and accurate imaging in the acute colitis mouse model. Taken together, this work reports a chemiluminescent probe for real-time monitoring of H2O2 dynamics in vitro and in vivo, which presents a reliable chemical tool for biosensing and disease diagnosis.

Redox Differences Between Neurons and Astrocytes In Vivo in Ischemic Brain Tissues of Rodents

Aims: Reactive oxygen species (ROS) are considered to play a key damaging role in brain during the development of ischemic stroke. To clarify how different ROS contribute to ischemic pathogenesis, innovative approaches for real-time in vivo detection of redox parameters are necessary. Results: Using highly sensitive genetically encoded biosensor HyPer7 and a fiber-optic neurointerface technology, we demonstrated that the level of hydrogen peroxide (H2O2) slowly increases in neurons and astrocytes of the ischemic area of the rat brain after middle cerebral artery occlusion during next 40 h; notably, in astrocytes the level is somewhat higher. Raman microspectroscopy in awake mice also revealed redox differences between mitochondria of neurons and astrocytes during acute ischemia caused by photothrombosis. Astrocytes demonstrated the overloading of the electron transport chain (ETC) with electrons after 1 h of ischemia, whereas neurons do not demonstrate changes in the amount of reduced electron carries. Innovation and Conclusion: The combination of novel in vivo approaches allows to detail redox events with spatiotemporal resolution. We demonstrated redox difference between neurons and astrocytes in damaged brain areas in vivo. An elevated loading of astrocytic ETC with electrons during the acute ischemia phase provides basis for the increased generation of superoxide anion radical (O2•-) with its following conversion to other reactive species. However, we observed increased H2O2 concentrations in astrocytes and neurons at later pathogenesis stages. During this period, ETC did not demonstrate an elevated loading with electrons, and therefore, increased H2O2 generation may be a phenomenon of secondary redox events. Antioxid. Redox Signal. 00, 000-000.

Detection of H2O2 and redox potential of an acute wound of rabbits with different sugar intakes based on a SERS-active microneedle

To detect H2O2 and redox potential of an acute wound simultaneously, a SERS-active microneedle was fabricated by integrating H2O2 and redox potential SERS probes into two grooves of an acupuncture needle, respectively. When the SERS-active microneedle was inserted into tissues, an acute wound was formed and the two SERS probes were introduced into the wound to sense H2O2 and redox potential of the wound. The feasibility of the SERS-active microneedle was evaluated ex vivo and in vivo. Both sugar deficiency and sugar excess induce increases in H2O2 and redox potential in most tissues. Short-term physiological disturbances eventually returned to normal levels in healthy organisms, and abnormal sugar intakes disrupt the normal physiological environment and induce stress responses in all tissues. The SERS-active microneedle for detection of H2O2 and redox potential would become a powerful tool, used for collecting physiological signals in different tissues to elucidate the mechanisms of wound healing and redox-related diseases.

Deregulated Myt3 translation predisposes islet β-cells to dysfunction under obesity-induced metabolic stress

In response to obesity-related metabolic stress, islet β-cells adapt (or compensate) by increasing their secretory function and mass. Yet, for unknown reasons, this compensation is reversed in some individuals at some point to induce β-cell failure and overt type 2 diabetes (T2D). We have previously shown that transcription factor Myt3 (St18) and its paralogs, Myt1 and Myt2, prevent β-cell failure. Myt3 was induced at post-transcriptional levels by obesity-related stress in both mouse and human β cells and its downregulation accompanied β-cell dysfunction during T2D development. Single-nucleotide polymorphisms in MYT3 were associated with an increased risk of developing human diabetes. We now demonstrate that Myt3 translation is regulated by an upstream open-reading frame that overlaps with the main Myt3 open-reading frame in mice. Disrupting this overlap enhances Myt3 translation in mouse β cells without metabolic stress but decreases it under high-fat-diet challenges. Consequently, this deregulation results in β-cell dysfunction and glucose intolerance in mice, accompanied by compromised expression of several β-cell function genes. These findings suggest that stress-induced Myt3 translation is part of the compensation mechanism that prevents β-cell failure.

Reactive oxygen and nitrogen species: multifaceted regulators of ovarian activity†

Reactive oxygen and nitrogen species are essential components of diverse intracellular signaling pathways. In addition to their involvement in apoptosis, reactive oxygen and nitrogen species are crucial in the regulation of multiple developmental and physiological processes. This review aims to summarize their role in the regulation of key ovarian stages: ovulation, maturation and postovulatory ageing of the oocyte, and the formation and regression of the corpus luteum. At the cellular level, a mild increase in reactive oxygen and nitrogen species is associated with the initiation of a number of regulatory mechanisms, which might be suppressed by increased activity of the antioxidant system. Moreover, a mild increase in reactive oxygen and nitrogen species has been linked to the control of mitochondrial biogenesis and abundance in response to increased cellular energy demands. Thus, reactive oxygen and nitrogen species should also be perceived in terms of their positive role in cellular signaling. On the other hand, an uncontrolled increase in reactive oxygen species production or strong down-regulation of the antioxidant system results in oxidative stress and damage of cellular components associated with ovarian pathologies and ageing. Similarly, the disturbance of signaling functions of reactive nitrogen species caused by dysregulation of nitric oxide production by nitric oxide synthases in ovarian tissues interferes with the proper regulation of physiological processes in the ovary.

Biological Models of Oxidative Purine DNA Damage in Neurodegenerative Disorders

Most DNA damage caused by oxidative metabolism consists of single lesions that can accumulate in tissues. This review focuses on two classes of lesions: the two 8-oxopurine (8-oxo-Pu) lesions that are repaired by the base excision repair (BER) enzyme and the four 5',8-cyclopurine (cPu) lesions that are repaired exclusively by the nucleotide excision repair (NER) enzyme. The aim is to correlate the simultaneous quantification of these two classes of lesions in the context of neurological disorders. The first half is a summary of reactive oxygen species (ROS) with particular attention to the pathways of hydroxyl radical (HO•) formation, followed by a summary of protocols for the quantification of six lesions and the biomimetic chemistry of the HO• radical with double-stranded oligonucleotides (ds-ODN) and calf thymus DNA (ct-DNA). The second half addresses two neurodegenerative diseases: xeroderma pigmentosum (XP) and Cockayne syndrome (CS). The quantitative data on the six lesions obtained from genomic and/or mitochondrial DNA extracts across several XP and CS cell lines are discussed. Oxidative stress contributes to oxidative DNA damage by resulting in the accumulation of cPu and 8-oxo-Pu in DNA. The formation of cPu is the postulated culprit inducing neurological symptoms associated with XP and CS.

Hydrogen peroxide in midbrain sleep neurons regulates sleep homeostasis

Sleep could protect animals from oxidative damage, yet the dynamic interplay between the redox state and sleep homeostasis remains unclear. Here, we show that acute sleep deprivation (SD) in mice caused a general increase in brain oxidation, particularly in sleep-promoting regions. In vivo imaging of intracellular hydrogen peroxide (H2O2) real-time dynamics revealed that in nigra sleep neurons, the increase in cytosolic but not mitochondrial H2O2 reflects sleep debt and tracks spontaneous wakefulness by positively correlating with wake duration. By controllably manipulating intraneuronal H2O2, we discovered that H2O2 elevation is required for compensatory sleep and causally promotes sleep initiation, at least partly dependent on transient receptor potential melastatin 2 (TRPM2) channel. However, excessive H2O2 induced brain inflammation and sleep fragmentation. Together, our study demonstrates intraneuronal H2O2 as a crucial signaling molecule that translates brain redox imbalance into sleep drive and underscores the significance of oxidative eustress in sleep homeostasis.

Antioxidant nanozymes: current status and future perspectives in spinal cord injury treatments

Spinal cord injury (SCI) is a life - altering neurological condition that carries significant global morbidity and mortality. It results in the disruption of motor and sensory pathways below the site of injury, often leading to permanent functional impairments and severely diminished quality of life. Despite decades of clinical and research efforts, current treatment options remain largely supportive, with limited success in promoting meaningful functional recovery or neural regeneration. In recent years, nanozymes have emerged as a promising frontier in the therapeutic landscape for SCI. These nanomaterial - based artificial enzymes offer several compelling advantages over their natural counterparts, including superior stability under physiological conditions, adjustable catalytic activity, cost - effective production, and prolonged shelf life. Unlike traditional therapeutic agents, nanozymes can be engineered to closely mimic the activity of key endogenous antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. By scavenging reactive oxygen species and attenuating oxidative damage, nanozymes help preserve neuronal integrity and support the intrinsic repair processes of the central nervous system. This review provides a comprehensive overview of the pathophysiological mechanisms underlying SCI and examines the classification and catalytic principles governing nanozyme activity. We delve into the molecular pathways through which nanozymes exert their neuroprotective effects, particularly their roles in modulating oxidative stress and suppressing inflammatory responses following injury. Additionally, we explore the current challenges associated with nanozyme development, such as biocompatibility, targeted delivery, and long - term safety, and discuss future directions for optimizing their therapeutic potential in clinical applications. By synthesizing emerging insights into antioxidant nanozyme - based strategies, this review aims to contribute to the evolving landscape of SCI treatment and to highlight the transformative potential of nanozymes in advancing neuroregenerative medicine. These innovative agents represent a new horizon in SCI management, offering renewed hope for improving neurological outcomes and quality of life in affected individuals.

Hyaluronic Acid-Based Bleaching Gels With NF_TiO2 and Violet LED: Efficacy and Cytotoxicity of Low-Concentration H2O2 for In-Office Bleaching

OBJECTIVE

To evaluate the efficacy and cytotoxicity of in-office bleaching gels with hyaluronic acid (HA) or carbomer 940 (CAR), titanium dioxide nanoparticles co-doped with nitrogen and fluorine (NF_TiO2), and hydrogen peroxide (HP; H2O2) at 1.5% and 6% with violet LED irradiation.

MATERIALS AND METHODS

48 bovine enamel/dentin discs (5 × 3 mm) stained with black tea for 24 h were assigned to six groups (n = 8): HA-1.5%HP + LED, HA-6%HP + LED, CAR-1.5%HP + LED, CAR-6%HP + LED, 35%HP-commercial (control), and a negative control (no treatment). The discs were placed in artificial pulp chambers (APCs) and underwent three 30-min bleaching sessions with 20 violet LED cycles (1-min activation, 30-s pause) at 7-day intervals. Extracts were applied to MDPC-23 cells, assessing color change (ΔE00), whiteness index (ΔWID), H2O2 diffusion, cell viability (CV), oxidative stress (OxS), and cell morphology (SEM). Data were analyzed by one-way ANOVA and Tukey post hoc test (α = 0.05).

RESULTS

Gels with HA showed no statistical difference in ΔE00 and ΔWID compared with 35%HP-commercial (p > 0.05). H2O2 diffusion and oxidative stress were lower in 1.5% and 6% HP groups. Cell viability was higher in 1.5% HP groups (p < 0.05). There were no changes in cell morphology.

CONCLUSION

Bleaching gels with HA, NF_TiO2 NPs, low H2O2 concentrations, and violet LED irradiation reduced cytotoxicity without compromising efficacy.

CLINICAL RELEVANCE

Experimental bleaching gels with hyaluronic acid, NF_TiO2 nanoparticles, low H2O2 concentrations, and combined with violet LED irradiation achieve similar efficacy to high-H2O2 gels (35%). This approach also promises to reduce cytotoxic damage, providing a safer in-office bleaching option.

Analyzing different aging theories in the context of the brain: DNA damage, inflammation, redox imbalance, and neurodevelopment intertwine

The neuronal tissue is notable for its unique regulation of the immune system, response to DNA damage, endurance against reactive oxygen and nitrogen species, and control of inflammatory pathways. Here, I discuss some uniqueness of the brain's aging process in light of the free radical theory of aging, DNA-damage accumulation, inflammaging, and aging as a consequence of a programmed developmental process. Key points include (i) the resilience of the neuronal tissue to oxidative stress; (ii) the neuron's efficiency in repairing learning-induced DNA damage, even with fewer repair pathways than other cell types; (iii) TLR9 and NFκB at the intersection of memory and inflammation; (iv) RELA linking the skin-brain axis during development, DNA damage response, and pro-inflammatory control; (v) PARP1 at the crossroad of all discussed aging theories. Data points to a "burden threshold" where the beneficial regulations of distinct pathways shift toward neurotoxic activities.

Self-Powered Biosensor Driven by a Hybrid Biofuel Cell with CuCoP-Polyoxometallate Composite as Both Cathode Catalyst and Sensing Interface

Abnormal concentrations of hydrogen peroxide (H2O2) are toxic to living cells and may induce a number of diseases. Herein, a self-powered miniaturized biosensor (SPB) based on an enzyme biofuel cell is constructed to monitor H2O2. This SPB significantly minimized the use of bioenzymes that often experience instability and lead to the high cost of biosensors. More specifically, a composite of polydopamine (PDA)-gold nanoparticles (AuNPs) is prepared as an anodic catalyst scaffold to immobilize glucose oxidase to efficiently catalyze the oxidation of glucose (fuel) due to its excellent biocompatibility and electrical conductivity. Upon the incorporation of CuCoP with a polyoxometalate H3PW12O40 (PW12), a nanoenzyme of CuCoP-PW12 composite is realized as a non-biological cathodic catalyst to replace the conventional cathode enzymes for the reduction of H2O2. The abundant catalytic active sites on CuCoP-PW12 and high electron transfer rate of PW12 result in a high catalytic activity toward H2O2 reduction at the cathode. Owing to a good synergy between the bioanode and abiotic-cathode, the prepared SPB exhibits two linear ranges (2-20 and 20-50 µm) and a low detection limit (0.0589 µm) toward H2O2 detection. Upon the use of H2O2 as a model analyte, this work demonstrates that SPB can be effectively applied in biomedical sensing.

Antioxidant activity of differently sized and sulfated konjac glucomannan fragments prepared by the relay strategy

Konjac glucomannan (KGM) is a polysaccharide with potential medical and functional properties. Here, the antioxidant and cytoprotective effects of sulfated and differently sized KGM fractions were investigated using various in vitro assays. The sulfated KGMs (SKGMs) were prepared via a relay strategy. First, Vitamin C (Vc)-H2O2 degradation was employed to obtain three soluble KGM fractions with different molecular weights. Second, nine KGM derivatives with varying sulfate content were obtained by the sulfur trioxide-pyridine method. The scavenging of DPPH, superoxide, and hydroxyl radicals was measured in vitro. The antioxidant activity of SKGM correlated positively with sulfate content. SKGM-I-2 displayed the most potent radical scavenging activity. Its purification by cellulose DEAE-52 column chromatography yielded four homogeneous fractions (SKGM-I-2a, SKGM-I-2b, SKGM-I-2c, and SKGM-I-2d). Pretreatment with SKGM-I-2d increased the viability of RAW264.7 cells exposed to H2O2. Moreover, SKGM-I-2d significantly increased the activity of superoxide dismutase and catalase, as well as the levels of glutathione, while regulating the expression of Keap1, Nrf2, and HO-1 in RAW264.7 cells. The present study suggests that SKGM-I-2d protects RAW264.7 cells against H2O2-induced oxidative injury through the activation of the Nrf2/Keap1 signaling pathway. These results provide a scientific basis for future studies linking the structural and functional features of KGM.

Complosome Regulates Hematopoiesis at the Mitochondria Level

The intracellular complement network, known as the complosome, regulates lymphocyte biology, which is well established. Recently, however, we demonstrated that the complosome is also expressed in hematopoietic stem/progenitor cells (HSPCs) in addition to lymphocytes. In our previous work, murine lineage-negative (Lin-) bone marrow (BM) mononuclear cells (BMMNC) from mice lacking the intracellular C3 and C5 complosome proteins displayed different responses to stress. Specifically, while C3-KO cells were more sensitive to oxidative stress, C5-KO cells showed greater resistance. To explore this intriguing observation at the metabolic level, we evaluated anaerobic and aerobic glycolysis, along with mitochondrial function, in Lin- BMMNC purified from C3-KO, C5-KO, and C5aR1-KO mice. We found that cells from complosome-deficient animals under steady-state conditions exhibited elevated lactate production and enhanced lactate dehydrogenase (LDH) release, indicating their reliance on anaerobic glycolysis. Interestingly, the uptake of a glucose fluorescent analog (2-NBDG) increased in C3-KO cells but decreased in C5-KO and C5aR1-KO cells compared to wild-type (WT) mice. Meanwhile, total ATP production in C3-KO cells, unlike that of C5 and C5aR1 mice, was reduced under steady-state conditions and did not change significantly after exposure to the mitochondrial-damaging agent hydrogen peroxide (H2O2). This suggests a greater dependence on anaerobic glycolysis in C3-KO cells than in C5-KO and C5aR1-KO cells. Finally, we assessed the integrity of mitochondrial membranes in the studied cells using MitoTracker green and deep red assays. Compared to WT cells, we observed that mitochondria from complosome mutant Lin-BMMNC accumulated fewer MitoTracker probes, indicating the presence of mitochondrial defects in these cells.

Sauchinone preserves cardiac function in doxorubicin-induced cardiomyopathy by inhibiting the NLRP3 inflammasome

BACKGROUND

Doxorubicin (Dox)-induced cardiomyopathy (DIC) is characterized by severe myocardial damage that can progress to dilated cardiomyopathy and potentially lead to heart failure. No effective prevention or treatment strategies are available for DIC. Sauchinone, a diastereomeric lignan isolated from Saururus chinensis, is known for its notable anti-inflammatory effects. However, a paucity of research on sauchinone in relation to heart disease exists, particularly regarding its role in DIC, which remains unclear.

PURPOSE

This study aimed to assess the therapeutic potential of sauchinone in alleviating cardiac injury and elucidate its potential molecular mechanism in DIC.

METHODS

Male C57BL/6J mice were used to construct chronic and acute DIC models in vivo. The mice were administered sauchinone intragastrically concurrently with the first injection of Dox to evaluate the therapeutic effect of sauchinone on DIC. H9c2, a rat cardiomyocyte cell line, was treated with various concentrations of sauchinone in conjunction with Dox to assess the protective effects of sauchinone on cardiomyocyte injury in vitro.

RESULTS

Supplementation with exogenous sauchinone mitigated Dox-induced cardiac atrophy, cardiac fibrosis, and ventricular remodeling, while preserving cardiac function. Sauchinone reduced Dox-induced abnormal apoptosis both in vitro and in vivo. Additionally, sauchinone restored mitochondrial function and decreased reactive oxygen species levels, which may be attributed to its activation of nuclear factor erythroid 2-related factor 2 (NRF2) signaling, thereby attenuating Dox-induced oxidative damage. Furthermore, sauchinone significantly inhibited the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome and reduced the cardiac infiltration of inflammatory factors, thereby alleviating oxidative stress and inhibiting the progression of DIC. The NLRP3 agonist nigericin abolished DIC progression, while the NLRP3 antagonist MCC950 further enhanced the beneficial effects of sauchinone on DIC progression both in vivo and in vitro.

CONCLUSIONS

The key novel finding of the present study is that the use of sauchinone, a diastereomeric lignan isolated from Saururus chinensis, effectively limits the progression of DIC. Specifically, sauchinone not only alleviates Dox-induced chronic cardiac injury but also significantly delays the progression of acute DIC. Mechanistically, inactivation of the NLRP3 inflammasome and NRF2-mediated antioxidant pathways have been identified as two critical signaling pathways regulated by sauchinone, which plays a vital role in blocking the progression of DIC. Sauchinone holds promise as a potential therapeutic approach for DIC or dilated cardiomyopathy.

Antioxidants in anti-Alzheimer's disease drug discovery

Oxidative stress is widely recognized as a key contributor to the pathogenesis of Alzheimer's disease (AD). While not the sole factor, it is closely linked to critical pathological features, such as the formation of senile plaques and neurofibrillary tangles. The development of agents with antioxidant properties has become an area of growing interest in AD research. Between 2015 and 2024, several antioxidant-targeted drugs for AD progressed to clinical trials, with increasing attention to the evaluation of antioxidant properties during their development. Oxidative stress plays a pivotal role in linking various AD hypotheses, underscoring its importance in understanding the disease mechanisms. Despite this, comprehensive reviews addressing advancements in AD drug development from the perspective of antioxidant capacity remain limited, hindering the design of novel compounds. This review aims to explore the mechanistic relationship between oxidative stress and AD, summarize methods for assessing antioxidant capacity, and provide an overview of antioxidant compounds with anti-AD properties reported over the past decade. The goal is to offer strategies for identifying effective antioxidant-based therapies for AD and to deepen our understanding of the role of oxidative stress in AD pathology.

Shrimp Virus Regulates ROS Dynamics via the Nrf2 Pathway to Facilitate Viral Replication

Reactive oxygen species (ROS) of hosts are widely involved in intracellular signaling and against pathogens. Viruses manipulate ROS homeostasis of hosts as a strategy to evade ROS-mediated negative effects of their infection, but the mechanisms remain unclear. The economically important aquaculture shrimp, Litopenaeus vannamei, is selected to investigate the molecular mechanism of how white spot syndrome virus (WSSV) regulates ROS dynamics and enhances viral replication. WSSV protein wsv220 binds to the repressor of shrimp nuclear factor erythroid 2-related factor 2 (LvNrf2), called Kelch-like ECH-associated protein 1 (LvKeap1), disrupting LvNrf2/LvKeap1 complex and facilitating LvNrf2 nuclear translocation. This activation of LvNrf2 causes up-regulation of antioxidant genes, including glucose-6-phosphate dehydrogenase (LvG6PDH), which increases nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione (GSH) production, effectively eliminating excessive ROS. Moreover, WSSV exploits LvNrf2 to establish a positive feedback loop by up-regulating viral immediate early gene wsv051, which further enhances wsv220 expression. Knockdown of LvNrf2 or LvG6PDH reduces WSSV replication and increases host ROS levels. Therefore, WSSV hijacks LvNrf2 pathway to maintain ROS homeostasis and establishes a positive feedback loop to facilitate WSSV replication. These findings reveal a novel molecular mechanism of viral manipulation of host ROS dynamics and suggest potential antiviral strategies targeting LvNrf2 pathway.

Cysteine variants in PMM2 lead to protein instability and higher sensitivity to oxidative stress in PMM2-CDG

PMM2-congenital disorder of glycosylation (PMM2-CDG) is caused by genetic defects in PMM2, the gene encoding phosphomannomutase 2. Effective therapies for this disorder remain elusive. Recent studies emphasize cysteine's vulnerability to oxidative modifications that can instigate disease by facilitating inter-protein disulfide bonding, reducing protein mobility, highlighting its potential as a target for therapeutic intervention. Specifically, five cysteine-related pathogenic mutants have been identified in PMM2-CDG, namely Phe11Cys (F11C), Tyr64Cys (Y64C), Tyr76Cys (Y76C), Tyr106Cys (Y106C) and Gly228Cys (G228C), however the fundamental molecular mechanisms are still not fully understood. In this study, compared to wild-type (WT), Cys pathogenic mutants induced structural destruction, augmented hydrophobic exposure, reduced thermal stability, and a propensity to aggregate at physiological temperatures. Meanwhile, Cys mutants were sensitive to oxidative stress, which in the evident formation of aggregation. Molecular dynamics simulation revealed alterations in the core region and subunit binding free energy of homologous PMM2, instigated by the pathophysiogenic variants. Based on previous articles, we found cysteine pathogenic mutants can be partly rescued by celastrol. In summary, our findings provide critical insights into the molecular and functional impacts of specific cysteine variants in the PMM2 enzyme, offering a foundation for exploring novel therapeutic strategies for the prevention and treatment of PMM2-CDG.

Precise fabrication of spatially engineered brochosomes for in-situ investigation of cellular ROS secretion

Monitoring released hydrogen peroxide (H2O2), one of the most stable and abundant reactive oxygen species (ROS) molecule that regulate intra- and inter-cellular redox signalling pathways, is significant for understanding pysio-pathological mechanisms. In this work, a spatially engineered brochosomes array was developed for in situ surface-enhanced Raman scattering (SERS) investigation of cellular H2O2 secretion. The array, inspired by the nanostructures of brochosomes, has been functionalized with H2O2-specific probes. The optimal pit distribution and size in the brochosomes array, as confirmed by finite-difference time-domain (FDTD) simulation results, supports efficient trapping of light by multiple internal reflections within the pit to suppress overall reflection, leading to enhanced SERS signals. Benefiting from the optimized plasmonic properties of brochosomes and the distinctive spectroscopic fingerprint of the SERS technique, the brochosomes array exhibited a high selectivity toward H2O2 with the limit of detection as low as 3.65 × 10-9 M. In situ cellular monitoring shown real-time tracking of H2O2 secretion from cells, with the brochosomes array maintaining high stability against complicated extracellular microenvironment. This bioinspired SERS platform offers a promising tool for oxidative stress research and could aid in the early diagnosis of ROS-related diseases.

An Overview of Oxidative Stress in Sex Chromosome Aneuploidies in Pediatric Populations

BACKGROUND

Oxidative stress, defined as an imbalance between reactive oxygen species and antioxidant defenses, plays a pivotal role in the pathogenesis of sex chromosome aneuploidies (SCAs), such as Turner syndrome (TS) and Klinefelter syndrome (KS). Pediatric patients with SCAs are particularly susceptible due to hormonal deficiencies, metabolic disturbances, and systemic complications.

METHODS

A comprehensive literature search was conducted in November 2024 using PubMed, Scopus, and Web of Science. Keywords included "antioxidants", "oxidative stress", "pediatrics", "Turner syndrome", "Klinefelter syndrome", and "sex chromosome aneuploidies". English-language articles were included without publication year restrictions. Relevant data on oxidative stress mechanisms and antioxidant interventions were systematically extracted.

RESULTS

The relationship between oxidative stress and SCAs can be described as bidirectional, where oxidative stress both contributes to and is exacerbated by aneuploidies. TS is marked by estrogen deficiency, cardiovascular anomalies, and metabolic dysfunction, all linked to heightened oxidative stress. KS is associated with hypogonadism, metabolic syndrome, and neurocognitive challenges, further exacerbated by oxidative damage. The aneuploid condition predisposes to increased oxidative stress in other SCAs, including 47,XXX and 47,XYY, as well as in high-grade aneuploidies. Emerging evidence highlights the therapeutic potential of antioxidants, including vitamin C, vitamin E, glutathione precursors, polyphenols, and melatonin. These interventions, when combined with hormonal therapies such as estrogen replacement in TS or testosterone replacement in KS, demonstrate synergistic effects in restoring redox balance and mitigating systemic complications.

CONCLUSIONS

Oxidative stress significantly impacts the progression of SCAs in pediatric populations, amplifying risks across metabolic, cardiovascular, and neurocognitive domains. Early, tailored antioxidant strategies, integrated with syndrome-specific hormonal therapies, could reduce long-term complications and improve patient outcomes. Future research should focus on standardizing protocols to optimize these interventions for pediatric patients with SCAs.

Monitoring in real time and far-red imaging of H2O2 dynamics with subcellular resolution

Monitoring H2O2 dynamics in conjunction with key biological interactants is critical for elucidating the physiological outcome of cellular redox regulation. Optogenetic hydrogen peroxide sensor with HaloTag with JF635 (oROS-HT635) allows fast and sensitive chemigenetic far-red H2O2 imaging while overcoming drawbacks of existing red fluorescent H2O2 indicators, including oxygen dependency, high pH sensitivity, photoartifacts and intracellular aggregation. The compatibility of oROS-HT635 with blue-green-shifted optical tools allows versatile optogenetic dissection of redox biology. In addition, targeted expression of oROS-HT635 and multiplexed H2O2 imaging enables spatially resolved imaging of H2O2 targeting the plasma membrane and neighboring cells. Here we present multiplexed use cases of oROS-HT635 with other green fluorescence reporters by capturing acute and real-time changes in H2O2 with intracellular redox potential and Ca2+ levels in response to auranofin, an inhibitor of antioxidative enzymes, via dual-color imaging. oROS-HT635 enables detailed insights into intricate intracellular and intercellular H2O2 dynamics, along with their interactants, through spatially resolved, far-red H2O2 imaging in real time.

Complosome as a new intracellular regulatory network in both normal and malignant hematopoiesis

Hematopoietic cells and lymphocytes arise from a common stem cell for both lineages. This explains why similar signaling networks regulate the development and biological functions of these cells. One crucial regulatory mechanism involves interactions with soluble mediators of innate immunity, including activated elements of the complement cascade (ComC). For many years, ComC proteins were thought to be synthesized only in the liver and released into blood to be activated by one of the three proteolytic cascades. The regulatory effects of activated components of ComC on hematopoietic stem progenitor cells (HSPCs) and mature hematopoietic cells have been well demonstrated in the past. However, recent data indicate that complement proteins are also expressed in several cell types, including lymphocytes and innate immune cells. This intracellular complement network has been named the "complosome." Recent evidence from our group shows that the complosome is also expressed in HSPCs and plays an important yet underappreciated role in the expansion, trafficking, and metabolism of these cells. We propose that the complosome, like its role in lymphocytes, is necessary for the optimal function of mitochondria in hematopoietic cells, including HSPCs. This opens a new area for investigation and potential pharmacological intervention into the complosome network in normal and malignant hematopoiesis.

Redox Regulation of cAMP-Dependent Protein Kinase and Its Role in Health and Disease

Protein kinase A (PKA) is a key regulator of cellular signaling that regulates key physiological processes such as metabolism, cell proliferation, and neuronal function. While its activation by the second messenger 3',5'-cyclic adenosine triphosphate (cAMP) is well characterized, recent research highlights additional regulatory mechanisms, particularly oxidative post-translational modifications, that influence PKA's structure, activity, and substrate specificity. Both the regulatory and catalytic subunits of PKA are susceptible to redox modifications, which have been shown to play important roles in the regulation of key cellular functions, including cardiac contractility, lipid metabolism, and the immune response. Likewise, redox-dependent modulation of PKA signaling has been implicated in numerous diseases, including cardiovascular disorders, diabetes, and neurodegenerative conditions, making it a potential therapeutic target. However, the mechanisms of crosstalk between redox- and PKA-dependent signaling remain poorly understood. This review examines the structural and functional regulation of PKA, with a focus on redox-dependent modifications and their impact on PKA-dependent signaling. A deeper understanding of these mechanisms may provide new strategies for targeting oxidative stress in disease and restoring balanced PKA signaling in cells.

Hydrogen peroxide signaling mediates dopamine-induced chromium stress tolerance in tomato

Toxic heavy metal chromium (Cr) poses significant risks to crop yields and human health through contamination of the food chain. Dopamine, a naturally occurring bioactive amine, can enhance plant tolerance to various abiotic stresses; however, its specific role in Cr stress tolerance and the associated molecular mechanisms remain largely unexplored. In this study, we demonstrate that root application of dopamine effectively mitigates Cr stress in tomato plants. Cr stress was found to decrease chlorophyll content, maximum photochemical efficiency, shoot growth, and biomass accumulation, while simultaneously increasing reactive oxygen species (ROS) accumulation, lipid peroxidation, and electrolyte leakage. Exogenous dopamine application significantly reduced excessive ROS accumulation and malondialdehyde levels, thereby alleviating oxidative stress. This was achieved through the enhancement of antioxidant enzyme activity, increased glutathione and phytochelatin contents, and the upregulation of the expression of respective encoding genes, including Cu-Zn SOD, POD, CAT1, APX, GR1, GSH2, and PCS. Additionally, dopamine treatment induced the expression of RBOH1 and reduced Cr content. Notably, exogenous H2O2 application also improved Cr tolerance, but the application of diphenyleneiodonium, an NADPH oxidase inhibitor, exacerbated Cr phytotoxicity and diminished the beneficial effects of dopamine on plant tolerance to Cr stress. These findings suggest that dopamine-induced H2O2 signaling plays a crucial role in enhancing Cr tolerance. This study elucidates a fundamental mechanism underlying dopamine-mediated Cr tolerance and expands our understanding of the stress resistance properties of dopamine in plants.

Redox chemical delivery system: an innovative strategy for the treatment of neurodegenerative diseases

INTRODUCTION

It is anticipated that the prevalence of illnesses affecting the central nervous system (CNS) will rise significantly due to longer lifespans and changing demography. Age-related decline in brain function and neuronal death are features of neurodegenerative disorders, such as Parkinson's disease, Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis, which provide formidable treatment challenges. Because most therapeutic drugs cannot across the blood-brain barrier (BBB) to reach the brain, there are still few treatment alternatives available despite a great deal of research.

AREAS COVERED

This study explores the role of redox chemical delivery systems in CNS drug delivery and addresses challenges associated with neurodegenerative disease (ND). Redox Chemical Delivery System offers a promising approach to enhancing leveraging redox reactions that facilitate the transport of therapeutic agents across the BBB. Through the optimization of medication delivery pathways to the brain, this technology has the potential to greatly improve the treatment of ND.

EXPERT OPINION

As our understanding of the biological underpinnings of ND deepens, the potential for effective interventions increases. Refining drug delivery strategies, such as RCDS, is essential for advancing CNS therapies from research to clinical practice. These advancements could transform the management of ND, improving both treatment efficacy and patient outcomes.

Mitochondrial classic metabolism and its often-underappreciated facets

For many decades, mitochondria were essentially regarded as the main providers of the adenosine triphosphate (ATP) required to maintain the viability and function of eukaryotic cells, thus the widely popular metaphor "powerhouses of the cell". Besides ATP generation - via intermediary metabolism - these intracellular organelles have also traditionally been known, albeit to a lesser degree, for their notable role in biosynthesis, both as generators of biosynthetic intermediates and/or as the sites of biosynthesis. From the 1990s onwards, the concept of mitochondria as passive organelles providing the rest of the cell, from which they were otherwise isolated, with ATP and biomolecules on an on-demand basis has been challenged by a series of paradigm-shifting discoveries. Namely, it was shown that mitochondria act as signaling effectors to upregulate ATP generation in response to growth-promoting stimuli and are actively engaged, through signaling and epigenetics, in the regulation of a plethora of cellular processes, ultimately deciding cell function and fate. With the focus of mitochondrial research increasingly placed in these "non-classical" functions, the centrality of mitochondrial intermediary metabolism to other mitochondrial functions tends to be overlooked. In this article, we revisit mitochondrial intermediary metabolism and illustrate how its intermediates, by-products and molecular machinery underpin other mitochondrial functions. A certain emphasis is given to frequently overlooked mitochondrial functions, namely the biosynthesis of iron-sulfur (Fe-S) clusters, the only known function shared by all mitochondria and mitochondrion-related organelles. The generation of reactive oxygen species (ROS) and their putative role in signaling is also discussed in detail.

Oxidative stress in vascular surgical diseases: mechanisms, impacts and therapeutic perspectives

The role of oxidative stress in vascular surgical diseases has increasingly been recognized as significant. This paper systematically reviews the specific mechanisms of oxidative stress in a various vascular surgical condition, including aortic dissection, abdominal aortic aneurysm, thrombosis, diabetic foot, and thromboangiitis obliterans, while also exploring related therapeutic strategies. Oxidative stress arises from an imbalance between free radicals and antioxidants, where excess reactive oxygen species and other free radicals can exacerbate inflammatory response. This paper delves into the pathogenic mechanisms of oxidative stress in the aforementioned diseases and discusses potential methods for utilizing antioxidants to reduce oxidative stress levels. Additionally, this paper highlights the challenges faced by current antioxidant therapies and identifies future research directions. By summarizing current research progress, this paper aims to provide a theoretical basis for more effective treatment strategies of vascular surgical diseases, with the hope of advancing the field.

Nanozymes: Innovative Therapeutics in the Battle Against Neurodegenerative Diseases

Neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD), represent a significant challenge to global health due to their progressive nature and the absence of curative treatments. These disorders are characterized by oxidative stress, protein misfolding, and neuroinflammation, which collectively contribute to neuronal damage and death. Recent advancements in nanotechnology have introduced nanozymes-engineered nanomaterials that mimic enzyme-like activities-as promising therapeutic agents. This review explores the multifaceted roles of nanozymes in combating oxidative stress and inflammation in neurodegenerative conditions. By harnessing their potent antioxidant properties, nanozymes can effectively scavenge reactive oxygen species (ROS) and restore redox balance, thereby protecting neuronal function. Their ability to modify surface properties enhances targeted delivery and biocompatibility, making them suitable for various biomedical applications. In this review, we highlight recent findings on the design, functionality, and therapeutic potential of nanozymes, emphasizing their dual role in addressing oxidative stress and pathological features such as protein aggregation. This synthesis of current research underscores the innovative potential of nanozymes as a proactive therapeutic strategy to halt disease progression and improve patient outcomes in neurodegenerative disorders.

Recent advances in electrochemical detection of reactive oxygen species: a review

Reactive oxygen species (ROS) are mainly generated as a result of cellular metabolism in plants and animals, playing a crucial role in cellular signaling mechanisms. The excessive generation of ROS leads to oxidative stress, which is associated with numerous diseases such as cancer, diabetes, and neurodegenerative disorders. Superoxide (O2˙-), hydrogen peroxide (H2O2), and hydroxyl radicals (˙OH) are the most common ROS involved in a wide range of human diseases. Therefore, sensitive and selective detection of these ROS is of paramount importance for understanding their roles in biological systems and for disease diagnosis. Among the various detection methods, electrochemical techniques have gained significant attention due to their high sensitivity, selectivity, and real-time monitoring capabilities. Electrochemical methods incorporate both organic and inorganic molecules to detect and monitor ROS, facilitating a deeper understanding of how their levels influence diseases linked to oxidative stress. This review aims to provide a critical discussion on the recent advances in electrochemical methods for detecting O2˙-, H2O2, and ˙OH. The review also highlights the application of these electrochemical techniques in detecting ROS in living cells and discusses the challenges and future perspectives in this field.

Redox signaling modulates axonal microtubule organization and induces a specific phosphorylation signature of microtubule-regulating proteins

Many life processes are regulated by physiological redox signaling, but excessive oxidative stress can damage biomolecules and contribute to disease. Neuronal microtubules are critically involved in axon homeostasis, regulation of axonal transport, and neurodegenerative processes. However, whether and how physiological redox signaling affects axonal microtubules is largely unknown. Using live cell imaging and super-resolution microscopy, we show that subtoxic concentrations of the central redox metabolite hydrogen peroxide increase axonal microtubule dynamics, alter the structure of the axonal microtubule array, and affect the efficiency of axonal transport. We report that the mitochondria-targeting antioxidant SkQ1 and the microtubule stabilizer EpoD abolish the increase in microtubule dynamics. We found that hydrogen peroxide specifically modulates the phosphorylation state of microtubule-regulating proteins, which differs from arsenite as an alternative stress inducer, and induces a largely non-overlapping phosphorylation pattern of MAP1B as a main target. Cell-wide phosphoproteome analysis revealed signaling pathways that are inversely activated by hydrogen peroxide and arsenite. In particular, hydrogen peroxide treatment was associated with kinases that suppress apoptosis and regulate brain metabolism (PRKDC, CK2, PDKs), suggesting that these pathways play a central role in physiological redox signaling and modulation of axonal microtubule organization. The results suggest that the redox metabolite and second messenger hydrogen peroxide induces rapid and local reorganization of the microtubule array in response to mitochondrial activity or as a messenger from neighboring cells by activating specific signaling cascades.

Diverse Fluorescent Probe Concepts for Detection and Monitoring of Reactive Oxygen Species

World-wide research on reactive oxygen species (ROS) continues to reveal new information about the role and impact of ROS on human health and disease. ROS are generated in live cells as a byproduct of aerobic metabolism. Physiological concentrations of cellular ROS are important for signaling and homeostasis, but excessive generation of ROS causes apoptotic and necrotic cell death and various health disorders. Fluorescence technology is a powerful tool to detect, monitor, and image cellular ROS. The present review provides an overview of diverse organic dye-based fluorescent probe concepts that involve modifications of traditional fluorescent dyes utilizing basic principles of dye chemistry and photophysics. Fluorescence responses of the probes and their specificity towards ROS are discussed through analyses of their photophysical and photochemical parameters. We also provide an outlook on future directions of ROS-responsive fluorescent dyes, which could enable the design and development of advanced probes for gaining deeper insights into redox biology.

Ganoderic Acid A Prevented Osteoporosis by Modulating the PIK3CA/p-Akt/TWIST1 Signaling Pathway

Osteoporosis is a disorder of decreased bone mass, microarchitectural deterioration, and fragility fractures. Ganoderma lucidum has been reported to have a variety of pharmacological activities, including immune regulation, anti-inflammation, antioxidation, sedative hypnosis, blood sugar and lipid regulation, and so on. However, the effective ingredients and the underlying mechanism of Ganoderma lucidum against osteoporosis are rarely clarified. Ganoderic acid A (GA-A), a triterpenoid, is one of the main components of Ganoderma lucidum. Our previous preliminary bioinformatic study found that it may affect bone metabolism, and it has been reported that GA-A has anti-osteoporosis potential via regulating MC3T3-E1 cells' osteogenic differentiation activity. Therefore, the aim of this study is to investigate the effects of Ganoderic acid A in preventing osteoporosis and uncover the potential mechanisms. In vivo, the 8-week-old C57BL/6J female mice were used to establish the osteoporosis model by ovariectomy (OVX). Two cell lines, MC3T3-E1 cells and primary osteoblasts, were used and induced with hydrogen peroxide (H2O2) to the state of oxidative stress in osteoporosis in vitro. We showed that Ganoderic acid A could inhibit OVX-induced bone loss in a dose-dependent manner and promote H2O2-induced osteogenic differentiation of primary osteoblasts and MC3T3-E1 cells. The mechanism-related signaling pathways were identified by network pharmacology screening and verified by bioinformatics. Results predicted that the target of Ganoderic acid A might be PIK3CA. Mechanistically, we found that PIK3CA activated the Akt receptor, then inhibited the expression of TWIST1 in the osteoblasts to up-regulate the protein expression of the osteogenic-related markers. Our results suggested that Ganoderic acid A could prevent OVX-induced osteoporosis and promote H2O2-induced osteogenic differentiation of primary osteoblasts and MC3T3-E1 cells. Ganoderic acid A might play an important role in the prevention of osteoporosis by modulating the PIK3CA/p-Akt/TWIST1 signaling pathway.

Current developments of pharmacotherapy targeting heme oxygenase 1 in cancer (Review)

Malignant tumors are non-communicable diseases that impact human health and quality of life. Identifying and targeting the underlying genetic drivers is a challenge. Heme oxygenase-1 (HO-1), a stress-inducible enzyme also known as heat shock protein 32, plays a crucial role in maintaining cellular homeostasis. It mitigates oxidative stress-induced damage and exhibits anti-apoptotic properties. HO-1 is expressed in a wide range of malignancies and is associated with tumor growth. However, the precise role of HO-1 in tumor development remains controversial. Drugs, both naturally occurring and chemically synthesized, can inhibit tumor growth by modulating HO-1 expression in cancer cells. The present review aimed to discuss biological functions of HO-1 pharmacological therapies targeting HO-1.

Antioxidant enzyme dynamics suggest the absence of oxidative stress in the canine endometrium across the estrous cycle

Oxidative stress plays a vital role in female fertility, yet the mechanisms regulating oxidative balance in the canine endometrium remain poorly understood. This study investigates the dynamics of the antioxidant enzyme system in the canine endometrium, focusing on superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GSR), and glutathione-S-transferase (GST), along with thiobarbituric acid reactive substances (TBARS) and total cellular thiols. Enzyme activities were revealed in five different phases of oestrus cycle in 25 dogs, using a spectrophotometric method: anestrus, proestrus, estrus, early diestrus and diestrus (n = 5 per group). Notably, a distinctive pattern in SOD and CAT activity was observed, with the former being characterised by a decrease from anestrus to estrus, and the later showed an opposite increase from anestrus to diestrus. In contrast, the activities of the glutathione-dependent enzymes GPX, GSR, and GST remained remarkably stable, although showing some fluctuations in different stages. TBARS analysis indicated an evident increase in oxidative stress-related lipid peroxidation in the canine endometrium only between anestrus and proestrus. Conversely, the thiol cell content remained consistent within the cycle stages. Our examination of enzyme ratios underscores a delicate balance in the normal canine uterus, effectively controlling oxidative stress without causing damage to lipids or proteins due to excessive reactive oxygen species. These findings contribute to our understanding of the unique physiological dynamics of the canine endometrium, offering valuable insights into the intricate regulation of oxidative stress in this context and its potential implications for female fertility.