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

Ozone: complicated effects in central nervous system diseases

Oxidative stress is closely related to various diseases. Ozone can produce redox reactions through its unique response. As a source of the oxidative stress response, the strong oxidizing nature of ozone can cause severe damage to the body. On the other hand, low ozone concentrations can activate various mechanisms to combat oxidative stress and achieve therapeutic effects. Some animal experiments and clinical studies have revealed the potential medical value of ozone, indicating that ozone is not just a toxic gas. By reviewing the mechanism of ozone and its therapeutic value in treating central nervous system diseases (especially ischemic stroke and Alzheimer's disease) and the toxic effects of ozone, we find that ozone inhalation and a lack of antioxidants or excessive exposure lead to harmful impacts. However, with adequate antioxidants, ozone can transmit oxidative stress signals, reduce inflammation, reduce amyloid β peptide levels, and improve tissue oxygenation. Similar mechanisms to those of possible new drugs for treating ischemic stroke and Alzheimer's disease indicate the potential of ozone. Nevertheless, limited research has restricted the application of ozone. More studies are needed to reveal the exact dose-effect relationship and healing effect of ozone.

A non-enzymatic hydrogen peroxide biosensor based on cerium metal-organic frameworks, hemin, and graphene oxide composite

This study presents the development of a novel non-enzymatic electrochemical biosensor for the real-time detection of hydrogen peroxide (H2O2) based on a composite of cerium metal-organic frameworks (Ce-MOFs), hemin, and graphene oxide (GO). The Ce-MOFs served as an efficient matrix for hemin encapsulation, while GO enhanced the conductivity of the composite. Characterization techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, UV-vis spectroscopy, and thermogravimetric analysis (TGA) confirmed the successful integration of hemin into the Ce-MOFs. The Ce-MOFs@hemin/GO-modified sensor demonstrated sensitive H2O2 detection due to the exceptional electrocatalytic activity of Ce-MOFs@hemin and the high conductivity of GO. This biosensor exhibited a linear response to H2O2 concentrations from 0.05 to 10 mM with a limit of detection (LOD) of 9.3 μM. The capability of the biosensor to detect H2O2 released from human prostate carcinoma cells was demonstrated, highlighting its potential for real-time monitoring of cellular oxidative stress in complex biological environments. To further assess its practical applicability, the sensor was tested in human serum samples, yielding promising results with recovery values ranging from 94.50 % to 103.29 %. In addition, the sensor showed excellent selectivity against common interfering compounds due to the outstanding peroxidase-like activity of the composite.

Multiple oxidative modifications on hemoglobin are elevated in breast cancer patients as measured by nanoflow liquid chromatography-tandem mass spectrometry

Breast cancer is strongly connected with elevated oxidative stress. Oxidative modifications of hemoglobin can serve as biomarkers for monitoring oxidative stress status in vivo. The structure of hemoglobin modifications derived from malondialdehyde (MDA) in human blood hemoglobin exists as N-propenal and dihydropyridine (DHP). This study reports the simultaneous quantification of eleven modified peptides in hemoglobin derived from MDA and advanced histidine oxidation in 16 breast cancer patients and 16 healthy women using nanoflow liquid chromatography nanoelectrospray ionization tandem mass spectrometry. The results reveal statistically significant increases in the formation of MDA-derived N-propenal and DHP of lysine and advanced oxidation of histidine in hemoglobin of breast cancer patients with the Mann-Whitney U-test p values < 0.0001 and the AUC of ROC between 0.9277 and 1.0. Furthermore, the elevation in modified peptides is significant in patients with early stages of breast cancer. By measuring these oxidative modifications in hemoglobin from a drop of blood, the role of lipid peroxidation and oxidative stress in breast cancer can be assessed using this sensitive assay.

Simultaneous binding of quercetin and catechin to FOXO3 enhances IKKα transcription inhibition and suppression of oxidative stress-induced acute alcoholic liver injury in rats

INTRODUCTION

Oxidative stress is one of the major contributors to acute alcoholic liver injury (AALI), which is a common alcoholic liver disease. Quercetin and catechin are flavonoid antioxidants present in plant foods and possess chemopreventive and chemotherapeutic activities. Quercetin and catechin are often included in the same meal and ingested together. While they show cooperative actions against oxidative damage, the underlying mechanisms behind their counteracting effects against oxidative stress-induced AALI remain poorly understood.

OBJECTIVES

The aim of this study was to understand the mechanism underlying the enhanced antioxidant effect of quercetin-catechin combination to alleviate AALI in rats.

METHODS

The ethanol (EtOH)-treated rats and H2O2-treated liver cells were used to demonstrate the enhanced antioxidant effect of quercetin and catechin. Then we used RNA-sequencing to compare quercetin alone, catechin alone and quercetin-catechin combination and then identified the critical role of IKKα combining with gene silencing and overexpression techniques. Its transcription factor, FOXO3 was found through yeast one-hybrid assay, luciferase reporter assay, EMSA and ChIP assay. Finally, the interaction between quercetin, catechin and FOXO3 was verified through molecular docking, UV-Vis absorption spectroscopy, fluorescence spectroscopy, and CD spectroscopy.

RESULTS

The study demonstrated the enhanced antioxidant effect of a quercetin-catechin combination in EtOH-treated rats and in H2O2-treated liver cells. Quercetin and catechin cooperatively inhibited IKKα/p53 pathway and activated Nrf2 signaling pathway. IKKα was a critical negative regulator in their joint action. FOXO3 bound to IKKα promoter to regulate IKKα transcription. Quercetin and catechin influenced FOXO3-IKKα binding through attaching directly to FOXO3 at different sites and altering FOXO3's secondary structures.

CONCLUSION

Our study revealed the mechanism of quercetin and catechin against oxidative stress-induced AALI through jointly interacting with transcription factor. This research opens new vistas for examining the joint effect of therapeutics towards functional proteins and confirms the chemopreventive effects of multiple flavonoids via co-regulation.

Thermal modulation of insecticide-induced hormetic and oxidative responses in insect pests

Environmental global changes are dramatically affecting agroecosystems. Insects have been shown to present various responses to multi-stress conditions (i.e., increase in temperature and exposure to contaminants). However, there is a knowledge gap on how temperature can modulate the hormetic effects in individuals sublethally exposed to chemical stressors. Here, we investigated how temperature (15, 20, 25, and 28 °C) modulates the effects of lethal and sublethal exposure to insecticides (imidacloprid) on the longevity, fecundity, and oxidative stress of a pest insect, the aphid Mysus persicae. Our results showed additive and interactive effects of temperature and insecticide on the stimulatory and oxidative responses of the insect pest. Overall, imidacloprid was 2.4-fold less toxic at 15 °C (3.547 μg/ml) than at 20 °C (1.482 μg/ml) and 24.6 to 19.8-fold less toxic than at 25 °C (0.144 μg/ml) and 28 °C (0.179 μg/ml) respectively. Furthermore, although the exposure of female aphids to most sublethal concentrations resulted in a decrease in their longevity and fecundity compared to the control, some of the sublethal concentrations produced positive effects in these parameters for the exposed individuals. The magnitude of induced sublethal effects varied between temperatures and occurred in similar ranges of low concentrations at temperatures 15 °C and 20 °C, and at temperatures 25 °C and 28 °C. Additionally, imidacloprid low concentrations induced a temperature-dependent production of reactive oxygen species in exposed insects at 12 and 24 h after exposure indicating oxidative stress. Our study supplies valuable data on how temperature modulates pesticide-mediated hormesis that can alter ecological interactions and functions within agroecosystems with potential implications in pest management.

Peroxiredoxin 2 mediates redox-stimulated adaptations to oxidative phosphorylation induced by contractile activity in human skeletal muscle myotubes

Skeletal muscle generates superoxide during contractions, which is converted to hydrogen peroxide (H2O2). H2O2 has been proposed to activate signalling pathways and transcription factors that regulate adaptive responses to exercise, but the concentration required to oxidize and activate key redox-sensitive signalling proteins in vitro is much higher than the typical intracellular levels seen in muscle after exercise. We hypothesized that 2-Cys-peroxiredoxins (PRDX), which rapidly oxidize in the presence of physiological concentrations of H2O2, serve as intermediary signalling molecules and play a crucial role in activating adaptive pathways following muscle contractions. This study has examined the human muscle myotube responses to contractile activity, or exposure to low extracellular concentrations (2.5-5 μM) of H2O2 and whether knock down of muscle PRDX2 alters the differential gene expression (DEG) that results from these stresses. Exposure of human skeletal muscle myotubes to a 15 min period of aerobic electrically stimulated isometric contractions or 5 μM H2O2 induced substantial changes in DEG with modification of many genes associated with adaptations of skeletal muscle to contractile activity. Common DEG in these conditions included upregulation of genes associated with increased mitochondrial oxidative phosphorylation, including COX1, COX2, COX3 and ATP6. In myotubes with PRDX2 knock down (94 % decrease in PRDX2 mRNA), the upregulation of genes associated with increased mitochondrial oxidative phosphorylation was abolished following contractile activity or exposure to H2O2. These data indicate that a common effect of contractile activity and exposure to "physiological" levels of H2O2 in human myotubes is to increase the expression of multiple genes associated with increased mitochondrial oxidative phosphorylation. Furthermore, these effects were abolished in PRDX2 knock down myotubes indicating that adaptations to upregulate multiple genes related to increased mitochondrial capacity in human muscle myotubes in response to exercise is both redox regulated and requires PRDX2 as an essential mediator of the effects of H2O2.

Oxidative stress disrupts vascular microenvironmental homeostasis affecting the development of atherosclerosis

Atherosclerosis is primarily an inflammatory reaction of the cardiovascular system caused by endothelial damage, leading to progressive thickening and hardening of the vessel walls, as well as extensive necrosis and fibrosis of the surrounding tissues, the most necessary pathological process causing cardiovascular disease. When the body responds to harmful internal and external stimuli, excess oxygen free radicals are produced causing oxidative stress to occur in cells and tissues. Simultaneously, the activation of inflammatory immunological processes is followed by an elevation in oxygen free radicals, which directly initiates the release of cytokines and chemokines, resulting in a detrimental cycle of vascular homeostasis abnormalities. Oxidative stress contributes to the harm inflicted upon vascular endothelial cells and the decrease in nitric oxide levels. Nitric oxide is crucial for maintaining vascular homeostasis and is implicated in the development of atherosclerosis. This study examines the influence of oxidative stress on the formation of atherosclerosis, which is facilitated by the vascular milieu. It also provides an overview of the pertinent targets and pharmaceutical approaches for treating this condition.

Embryonic exposure to flubendiamide induces hepatotoxicity in domestic chicks by altering drug-metabolizing enzymes, antioxidant status, and liver function

Pesticides have increased crop yield but severely impacted ecosystems and non-target organisms. Flubendiamide, a new generation pesticide, targets insect larvae but also affects non-target organisms. This study examines the effects of lowest observed effect concentration of technical grade flubendiamide (0.5 µg/µL) flubendiamide on chick liver, focusing on cytochrome P450 (CYP) enzyme expression, oxidative stress, and liver damage. Chick embryos treated with flubendiamide showed significant alterations in CYP mRNA and protein levels, indicating increased toxicant accumulation. Elevated CYP3A4, CYP1A1, CYP1A2, and CYP2C19 levels were noted, suggesting enhanced biotransformation and detoxification processes. However, increased oxidative byproducts led to oxidative stress, as evidenced by decreased glutathione (GSH) levels and elevated superoxide dismutase (SOD) and catalase activities. DCFDA staining confirmed increased hydrogen peroxide (H2O2) levels, indicating heightened reactive oxygen species (ROS). Liver function tests revealed significant increases in serum ALP, ALT, and AST levels, indicating acute liver damage. Histopathological analysis showed structural liver damage, including expanded sinusoidal spaces, impaired portal veins, and compromised hepatocyte architecture. These findings underscore flubendiamide's potential hepatotoxicity in non-target organisms, emphasizing the need for cautious pesticide use to minimize environmental impacts.

Assessing the Effects of Palm Oil Consumption on Life Expectancy, Metabolic Markers, and Oxidative Stress in Drosophila melanogaster

Palm oil is the world's second most consumed vegetable oil, sourced from the tropical palm tree Elaeis guineensis. Its consumption has been associated with a higher incidence of cardiovascular disease, largely due to its elevated palmitic acid content, however those studies are contradictory and inconclusive. Wishing to contribute to this issue, the present study aims to investigate the molecular and toxicological effects of this oil and the involvement of oxidative stress, given its role in metabolic dysfunctions using Drosophila melanogaster. This study examines survival rates, and locomotor performance, oxidative status by analysis of lipid peroxidation, ROS formation, thiol levels and antioxidant enzyme activity, and metabolic parameters such as cholesterol and triglycerides, glucose, trehalose and glycogen levels. Exposure to palm oil concentrations of 10% and 30% resulted in a shortened lifespan, reduced locomotor performance, and increased lipid peroxidation, with lower thiol levels and antioxidant enzyme modulation. Cholesterol levels was increased whereas energetic fuels as glucose and glycogen and trehalose were decreased mainly after 10 days of exposure. These findings underscore the detrimental effects of high-fat diets containing palm oil on lifespan, antioxidant defenses, and metabolism in Drosophila melanogaster. This data highlights the potential risk associated with the habitual consumption of palm oil in the daily diet by population, particularly concerning cardiovascular health and metabolic function.

The protective effects of fisetin in metabolic disorders: a focus on oxidative stress and associated events

Abstract

Metabolic syndrome is increasingly recognized as a significant precursor to various chronic diseases, contributing to a growing public health concern. Its complex pathogenesis involves multiple interrelated mechanisms, with oxidative stress identified as a cornerstone that exacerbates other pathogenic pathways. This study elucidates the molecular mechanisms by which oxidative stress intensifies metabolic disturbances, particularly insulin resistance. Some recent research has focused on fisetin, a natural product known for its potential benefits in diabetes and its associated microvascular and macrovascular complications. This paper compiles a comprehensive collection of findings by reviewing studies conducted over the past decade, detailing dosages, investigated markers, and their respective outcomes. Notably, a recurrent finding was fisetin's ability to enhance Nrf2, a principal regulator of antioxidant defense, in both metabolic and non-metabolic diseases. Furthermore, intriguing results suggest that the effects of Nrf2 extend beyond oxidative stress modulation, demonstrating favorable impacts on tissue-specific functions in metabolic regulation. This highlights fisetin not only as an antioxidant but also as a potential therapeutic agent for improving metabolic health and mitigating the effects of metabolic syndrome. In conclusion, fisetin can enhance the body's antioxidant defenses by modulating the Nrf2 pathway while also improving metabolic health through its effects on inflammation, cell survival, and energy metabolism, offering a comprehensive approach to managing metabolic disorders.

Graphical Abstract

Glucose Oxidase-Coated Calcium Peroxide Nanoparticles as an Innovative Catalyst for In Situ H2O2-Releasing Hydrogels

In situ forming and hydrogen peroxide (H2O2)-releasing hydrogels have been considered as attractive matrices for various biomedical applications. Particularly, horseradish peroxidase (HRP)-catalyzed crosslinking reaction serves efficient method to create in situ forming hydrogels due to its advantageous features, such as mild reaction conditions, rapid gelation rate, tunable mechanical strength, and excellent biocompatibility. Herein, a novel HRP-crosslinked hydrogel system is reported that can produce H2O2 in situ for long-term applications, using glucose oxidase-coated calcium peroxide nanoparticles (CaO2@GOx NPs). In this system, CaO2 gradually produced H2O2 to support the HRP-mediated hydrogelation, while GOx further catalyzed the oxidation of glucose for in situ H2O2 generation. As the hydrogel is formed rapidly is expected and the H2O2 release behavior is prolonged up to 10 days. Interestingly, hydrogels formed by HRP/CaO2@GOx-mediated crosslinking reaction provided a favorable 3D microenvironment to support the viability and proliferation of fibroblasts, compared to that of hydrogels formed by either HRP/H2O2 or HRP/CaO2/GOx-mediated crosslinking reaction. Furthermore, HRP/CaO2@GOx-crosslinked hydrogel enhanced the angiogenic activities of endothelial cells, which is demonstrated by the in vitro tube formation test and in ovo chicken chorioallantoic membrane model. Therefore, HRP/CaO2@GOx-catalyzed hydrogels is suggested as potential in situ H2O2-releasing materials for a wide range of biomedical applications.

Decoding the role of durum wheat ascorbate peroxidase TdAPX7B-2 in abiotic stress response

APX proteins are H2O2-scavenging enzymes induced during oxidative stress. In the first part of this study, we provided an extensive knowledge on the APX family of Triticum durum, TdAPX and their related TdAPX-R, via the genome wide analysis. The outcomes showed that these proteins are clustered into four major subgroups. Furthermore, the exon-intron structure and the synteny analyses revealed that during evolution the genes TdAPX and TdAPX-R are relatively conserved. Besides, during their evolution, these genes underwent purifying selection pressure and were duplicated in segmental. In parallel, the analysis of the conserved motifs and the multiple sequence alignment demonstrated that the residues involved in the active sites, heme- and cations-binding are conserved only in TdAPX proteins. Following the RNA-seq data and the regulatory elements analyses, we focused in the second part of this study on the functional characterization of TdAPX7B-2. The qRT-PCR data showed the upregulation of TdAPX7B-2 essentially in leaves of durum wheat exposed to salt, cold, drought, metals and ABA treatments. The tolerance phenotype of the TdAPX7B-2-expressing Arabidopsis lines to salt, direct-induced oxidative stress and heavy metals was manifested by the development of root system, proline accumulation and induction of the antioxidant CAT, SOD and POD enzymes to maintain the non-toxic H2O2 levels. Likewise, the response to salt stress and direct-oxidative stress of the transgenic lines was accompanied mainly by the induction of AtNCED3, AtRD29A/B and AtERD1.

The RNA chaperone Hfq is a novel regulator of catalase expression and hydrogen peroxide-induced oxidative stress response in Listeria monocytogenes EGD-e

The RNA chaperone Hfq plays a pivotal role in many bacteria, acting as a regulator of gene expression and promoting interaction between mRNA-sRNA pairs in Gram-negative bacteria. However, in Gram-positive bacteria this protein is expendable for riboregulation, and the main function of Hfq remains elusive. This work unveils a novel function for Hfq in the oxidative stress response of the human pathogen Listeria monocytogenes, a Gram-positive bacterium responsible for the infectious disease listeriosis. Disruption of hfq gene (Δhfq) results in a hypersensitive phenotype towards hydrogen peroxide (H2O2), in which sub-inhibitory concentrations of this reactive oxygen species (ROS) severely impair growth and viability of L. monocytogenes EGD-e. A Δhfq-complemented strain does not show this phenotype. This Hfq-dependent regulation of oxidative stress seems specific for H2O2, as exposure to superoxides caused no differences. We demonstrate that Hfq has a dual regulatory role in the expression of catalase (kat), the key enzyme involved in H2O2 detoxification. Hfq influences kat transcription under non-stress conditions by modulating the levels of the transcriptional repressor PerR, and also acts post-transcriptionally by stabilizing kat mRNA under H2O2-induced stress. Indeed, enzymatic assays revealed reduced catalase activity in Δhfq cell extracts, a result unrelated to differences in cellular iron content. Bacterial infection triggers immune cells to produce massive amounts of ROS, like H2O2. We show that inactivation of Hfq increases susceptibility to macrophage killing, connecting Hfq with the stress resistance and virulence of L. monocytogenes EGD-e. Overall, these findings advance the understanding of Hfq function within Gram-positive bacteria, revealing for the first time that Hfq is a novel regulator of catalase expression. This paves the way for the study of yet unknown oxidative stress response pathways regulated by Hfq in other pathogens.

Proteolethargy is a pathogenic mechanism in chronic disease

The pathogenic mechanisms of many diseases are well understood at the molecular level, but there are prevalent syndromes associated with pathogenic signaling, such as diabetes and chronic inflammation, where our understanding is more limited. Here, we report that pathogenic signaling suppresses the mobility of a spectrum of proteins that play essential roles in cellular functions known to be dysregulated in these chronic diseases. The reduced protein mobility, which we call proteolethargy, was linked to cysteine residues in the affected proteins and signaling-related increases in excess reactive oxygen species. Diverse pathogenic stimuli, including hyperglycemia, dyslipidemia, and inflammation, produce similar reduced protein mobility phenotypes. We propose that proteolethargy is an overlooked cellular mechanism that may account for various pathogenic features of diverse chronic diseases.

Low-Dose Ozone as a Eustress Inducer: Experimental Evidence of the Molecular Mechanisms Accounting for Its Therapeutic Action

Ozone (O3) is an unstable, highly oxidative gas that rapidly decomposes into oxygen. The therapeutic use of O3 dates back to the beginning of 20th century and is currently based on the application of low doses, inducing moderate oxidative stress that stimulates the antioxidant cellular defences without causing cell damage. In recent decades, experimental investigations allowed the establishment of some basic mechanisms accounting for the therapeutic effects of eustress-inducing low-dose O3. In this review, special attention was given to the impact of O3 administration on the cell oxidant-antioxidant status, O3 anti-inflammatory and analgesic properties, efficacy in improving tissue regeneration, and potential anticancer action. Low O3 concentrations proved to drive the cell antioxidant response mainly by activating nuclear factor erythroid 2-related factor 2. The anti-inflammatory effect relies on the downregulation of pro-inflammatory factors and the modulation of cytokine secretion. The painkilling action is related to anti-inflammatory processes, inhibition of apoptosis and autophagy, and modulation of pain receptors. The regenerative potential depends on antioxidant, anti-inflammatory, anti-apoptotic, and pro-proliferative capabilities, as well as fibroblast activation. Finally, the anticancer potential is based on oxidant and anti-inflammatory properties, as well as the inhibition of cell proliferation, invasion, and migration and the induction of apoptosis.

Synthesis, antioxidant and structural properties of modified ebselen derivatives and conjugates

Ebselen is a drug in clinical trials for several diseases and degenerative conditions where oxidative stress is implicated. A series of novel ebselen analogues was synthesized, including hydroxy-, alkoxy- and aminomethylene derivatives, as well as hybrid species where the ebselen selenium atom is shared with other potent antioxidant structures, such as cyclic selenenyl sulfide, cyclic seleninate ester and spirodioxyselenurane moieties. Conjugates of ebselen with cholesterol, prednisolone and the radical inhibitor BHT were also prepared. The products were tested for antioxidant activity in an NMR-based assay by measuring the rate of consumption of benzyl thiol or the production of dibenzyl disulfide in the presence of hydrogen peroxide when catalyzed by the ebselen analogues. Activities ranged from 12 to 0.12 times that of ebselen. The oxidation of the 2-hydroxymethylene derivative of ebselen was faster than thiolysis in the initial step and the overall rate was further accelerated under basic conditions. The corresponding selenenyl sulfide analogue underwent very slow disproportionation under neutral conditions that was enhanced by the presence of a base catalyst. During investigation of possible fluxional behaviour of a bis-amide analogue, an unusual tetraphenyphosphonium salt of a tricoordinate selenium pincer anion was discovered with exceptionally potent catalytic activity, 130 times that of ebselen. In addition to rate measurements, X-ray crystallography and DFT computational methods were also employed to gain further structural and mechanistic insights.

Mouse models used to test the role of reactive oxygen species in aging and age-related chronic diseases

With the development of the technology to generate transgenic and knockout mice in the 1990s, investigators had a powerful tool to directly test the impact of altering a specific gene on a biological process or disease. Over the past three decades, investigators have used transgenic and knockout mouse models, which have altered expression of antioxidant genes, to test the role of oxidative stress/damage in aging and age-related diseases. In this comprehensive review, we describe the studies using transgenic and knockout mouse models to test the role of oxidative stress/damage in aging (longevity) and three age-related diseases, e.g., sarcopenia, cardiac aging, and Alzheimer's Disease. While longevity was consistently altered only by one transgenic and one knockout mouse model as predicted by the Oxidative Stress Theory of Aging, the incidence/progression of the three age-related diseases (especially Alzheimer's disease) were robustly impacted when the expression of various antioxidant genes was altered using transgenic and knockout mouse models.

Unveiling the Longevity Potential of Natural Phytochemicals: A Comprehensive Review of Active Ingredients in Dietary Plants and Herbs

Ancient humans used dietary plants and herbs to treat disease and to pursue eternal life. Today, phytochemicals in dietary plants and herbs have been shown to be the active ingredients, some of which have antiaging and longevity-promoting effects. Here, we summarize 210 antiaging phytochemicals in dietary plants and herbs, systematically classify them into 8 groups. We found that all groups of phytochemicals can be categorized into six areas that regulate organism longevity: ROS levels, nutrient sensing network, mitochondria, autophagy, gut microbiota, and lipid metabolism. We review the role of these processes in aging and the molecular mechanism of the health benefits through phytochemical-mediated regulation. Among these, how phytochemicals promote longevity through the gut microbiota and lipid metabolism is rarely highlighted in the field. Our understanding of the mechanisms of phytochemicals based on the above six aspects may provide a theoretical basis for the further development of antiaging drugs and new insights into the promotion of human longevity.

Hydrogen peroxide disrupts the regulatory pathway of saliva secretion in two salivary acinar rat cell lines

Background

Secretion of saliva is controlled by autonomic nerve signals via regulation of Ca2+-dependent ion transport across acinar cell membranes. Oxidative stress may affect this process, leading to a decrease in saliva production. This study investigates elements of the Ca2+ regulatory pathway and their vulnerability to hydrogen peroxide-induced oxidative stress.

Methods

Rat parotid and submandibular salivary gland acinar cell lines were exposed to different hydrogen peroxide concentrations to simulate oxidative stress. Cell viability and intracellular reactive oxygen species were measured, mRNA levels were assessed via RT-qPCR, and protein expression was studied using western blot and immunofluorescence microscopy.

Results

Elevated concentrations of hydrogen peroxide reduced cell viability and increased intracellular levels of reactive oxygen species and led to a decrease in cholinergic receptor muscarinic 3 and adrenoreceptor alpha 1A mRNA and protein levels in both cell lines. In parotid gland cells, both mRNA and protein levels of stromal interaction molecule 1 and Orai1 decreased with increasing concentrations of hydrogen peroxide. In contrast, in submandibular gland cells stromal interaction molecule 1 and Orai1 displayed differential mRNA and protein expression levels.

Conclusion

Our study revealed that hydrogen peroxide exposure alters rat parotid and submandibular acinar cells, increasing reactive oxygen species and reducing autonomic receptor expression. Differential mRNA and protein expression of stromal interaction molecule 1 and Orai1 highlight complex oxidative stress effects on Ca2⁺ signaling. Most likely these effects will be deleterious to salivary secretion, but some effects may be protective.

tRNA modification enzyme-dependent redox homeostasis regulates synapse formation and memory

Post-transcriptional modification of RNA regulates gene expression at multiple levels. ALKBH8 is a tRNA-modifying enzyme that methylates wobble uridines in a subset of tRNAs to modulate translation. Through methylation of tRNA-selenocysteine, ALKBH8 promotes selenoprotein synthesis and regulates redox homeostasis. Pathogenic variants in ALKBH8 have been linked to intellectual disability disorders in the human population, but the role of ALKBH8 in the nervous system is unknown. Through in vivo studies in Drosophila, we show that ALKBH8 controls oxidative stress in the brain to restrain synaptic growth and support learning and memory. ALKBH8 null animals lack wobble uridine methylation and exhibit reduced protein synthesis in the nervous system, including a specific decrease in selenoprotein levels. Either loss of ALKBH8 or independent disruption of selenoprotein synthesis results in ectopic synapse formation. Genetic expression of antioxidant enzymes fully suppresses synaptic overgrowth in ALKBH8 null animals, confirming oxidative stress as the underlying cause of dysregulation. ALKBH8 null animals also exhibit associative memory impairments that are reversed by pharmacological antioxidant treatment. Together, these findings demonstrate the critical role of tRNA wobble uridine modification in redox homeostasis in the developing nervous system and reveal antioxidants as a potential therapy for ALKBH8-associated intellectual disability.

Stress-induced modification of Escherichia coli tRNA generates 5-methylcytidine in the variable loop

There has been recent interest in trying to understand the connection between transfer RNA (tRNA) posttranscriptional modifications and changes in-cellular environmental conditions. Here, we report on the identification of the modified nucleoside 5-methylcytidine (m5C) in Escherichia coli tRNAs. This modification was determined to be present at position 49 of tRNA Tyr-QUA-II. Moreover, m5C levels in this tRNA are significantly elevated under high reactive oxygen specieis (ROS) conditions in E. coli cells. We identified the known ribosomal RNA methyltransferase rsmF as the enzyme responsible for m5C synthesis in tRNA and enzyme transcript levels are responsive to elevated levels of ROS in the cell. We further find that changes in m5C levels in this tRNA are not specific to Fenton-like reaction conditions elevating ROS, but heat shock can also induce increased modification of tRNA Tyr-QUA-II. Altogether, this work illustrates how cells adapt to changing environmental conditions through variations in tRNA modification profiles.

Supramolecular PEG-DNA-Ferrocene Nanogels for Synergistically Amplified Chemodynamic Therapy via Cascade Reactions

Chemodynamic therapy (CDT) has been limited by the tumor microenvironment, such as the low concentration of hydrogen peroxide (H2O2). The combination of therapeutic strategies that increase H2O2 with CDT can synergistically enhance the therapeutic effect. Herein, a novel supramolecular PEG-DNA-ferrocene nanogel that can codeliver glucose oxidase (GOx) and the hypoxia-activable prodrug tirapazamine (TPZ) was developed to synergistically amplify CDT via cascade reactions. The DNA nanogel was size-controllable and DNase I-responsive and exhibited good biocompatibility. Induced by oxygen consumption and H2O2 generation in the catalytic reaction of GOx, the drugs TPZ and ferrocene in the nanogel underwent the hypoxia-based reaction and the Fenton reaction, respectively. The vitro model tests, intracellular ROS test, MTT experiments, and DNA damage assay demonstrated that the H2O2-based cascade Fenton reaction and the hypoxia-based cascade reaction obviously increased ·OH generation and promoted the apoptosis of cancer cells. This cascade supramolecular nanoplatform provided a promising therapeutic strategy to synergistically amplify CDT.

Comparison of the bioactivity and apoptotic responses of hyaline cartilage chondrocytes and fibrocartilage chondrocytes obtained by bone marrow stimulation in rats

Objective

The microfracture technique is often considered the standard therapy for treating cartilage defects. The aim of the treatment is the migration of mesenchymal stem cells from the bone marrow into the defect area. However, this regeneration process often results in the formation of fibrocartilage instead of natural hyaline cartilage, due to cellular mechanisms whose causes are not well understood. Therefore, in this study, the differences in bioactivity and apoptosis of fibrocartilage tissue-derived chondrocytes (FCh) obtained by bone marrow stimulation and natural hyaline cartilage tissue-derived chondrocytes (HCh) in the knee joint of rats were compared.

Methods

A total of 24 Wistar albino rats were used in this study, and one hind leg of each animal was operated on, while the other served as a control. A 2-step surgical procedure was performed: First, a microfracture was generated at a 2 mm × 2 mm cartilage defect area in the medial condyle of the femur after a left knee arthrotomy. Second, 6 weeks later, after a double knee arthrotomy, fibrocartilage from the microfracture area of the left knee and 2 × 2 mm of hyaline cartilage from the medial femoral condyle of the right knee were harvested. Chondrocytes were isolated and grouped as HCh or FCh, and cell viability and apoptosis were determined by MTT (4,5-dimethylthiazol -2-yl)-2,5-diphenyltetrazolium bromide) and caspase-3 assays using enzyme-linked immunosorbent assay (ELISA) kits.

Results

Fibrocartilage tissue-derived chondrocytes showed similar bioactivity and apoptotic response as HCh under physiological conditions. However, low-dose H2O2 decreased viability (bioactivity) and increased apoptosis in FCh without affecting HCh. High-dose H2O2 reduced the bioactivity of both cell types and induced apoptosis, while the response of FCh to oxidative stress was more aggressive than that of HCh.

Conclusion

The different response patterns in oxidative stress may provide a basis for understanding the limited survival time of bone marrow-derived fibrocartilage tissue induced by microfractures.

Level of Evidence

N/A.

Potent ROS inhibitors from Zanthoxylum armatumDC of Nepali origin

A bioassay-guided isolation on the plant Zanthoxylum armatum DC yielded compounds tambulin (1), and prudomestin (2), from ethyl acetate fraction which showed the highest ROS inhibiting activity (IC50 = 17.8 ± 1.1 µg/mL). Structure elucidation of pure compounds was done using mass and NMR spectroscopic techniques. Compounds 1 and 2 revealed potent ROS inhibition with IC50 = 7.5 ± 0.3 and 1.5 ± 0.3 µg/mL, respectively, as compared to standard ibuprofen (IC50 = 11.2 ± 1.9 µg/mL). Likewise, both compounds 1 and 2 showed potent antioxidant activity with IC50 = 32.65 ± 0.31 and 26.96 ± 0.19 µg/mL, respectively. In vitro studies were supported by molecular docking and drug-likeliness properties. In silico studies of 1 and 2 with cyclooxygenase-2 (COX-2) showed perfect binding affinity with binding energies of -8.4 and -8.6 kcal/mol, respectively, comparable to standard ibuprofen (-7.7 kcal/mol). Drug likeness and ADMET showed higher gastrointestinal absorption of 1 and 2 and no toxic impact.

Apelin regulates mitochondrial dynamics by inhibiting Mst1-JNK-Drp1 signaling pathway to reduce neuronal apoptosis after spinal cord injury

In the secondary injury stage of spinal cord injury, mitochondrial dysfunction leads to decreased ATP production, increased ROS production, and activation of the mitochondria-mediated apoptosis signaling pathway. This ultimately intensifies neuronal death and promotes the progression of the injury. Apelin, a peptide produced by the APLN gene, has demonstrated promise in the treatment of spinal cord injury. The aim of this study was to investigate how Apelin protects neurons after spinal cord injury by influencing the mitochondrial dynamics. The results showed that Apelin has the ability to reduce mitochondrial fission, enhance the mitochondrial membrane potential, improve antioxidant capacity, facilitate the clearance of excess ROS, and ultimately decrease apoptosis in PC12 cells. Moreover, Apelin is overexpressed in neurons in the damaged part of the spinal cord, contributing to reduce mitochondrial fission, improve antioxidant capacity, increase ATP production, decrease apoptosis, promote spinal cord morphological repair, maintain the number of nissl bodies, and enhance signal transduction in the descending spinal cord pathway. Apelin exerts its protective effect by inhibiting the Mst1-JNK-Drp1 signaling pathway. In summary, our study further improved the effect of Apelin in the treatment of spinal cord injury, revealed the mechanism of Apelin in protecting damaged neurons after spinal cord injury by maintaining mitochondrial homeostasis, and provided a new therapeutic mechanism for Apelin in spinal cord injury.

Ablating the glutaredoxin-2 (Glrx2) gene protects male mice against non-alcoholic fatty liver disease (NAFLD) by limiting oxidative distress

In the present study, we investigated the consequences of deleting the glutaredoxin-2 gene (Glrx2-/-) on the development of non-alcoholic fatty liver disease (NAFLD) in male and female C57BL6N mice fed a control (CD) or high-fat diet (HFD). We report that the HFD induced a significant increase in body mass in the wild-type (Wt) and Glrx2-/- male, but not female, mice, which was associated with the hypertrophying of the abdominal fat. Interestingly, while the Wt male mice fed the HFD developed NAFLD, the deletion of the Glrx2 gene mitigated vesicle formation, intrahepatic lipid accumulation, and fibrosis in the males. The protective effect associated with ablating the Glrx2 gene in male mice was due to enhancement of mitochondrial redox buffering capacity. Specifically, liver mitochondria from male Glrx2-/- fed a CD or HFD produced significantly less hydrogen peroxide (mtH2O2), had lower malondialdehyde levels, greater activities for glutathione peroxidase and thioredoxin reductase, and less protein glutathione mixed disulfides (PSSG) when compared to the Wt male mice fed the HFD. These effects correlated with the S-glutathionylation of α-ketoglutarate dehydrogenase (KGDH), a potent mtH2O2 source and key redox sensor in hepatic mitochondria. In comparison to the male mice, both Wt and Glrx2-/- female mice displayed almost complete resistance to HFD-induced body mass increases and the development of NAFLD, which was attributed to the superior redox buffering capacity of the liver mitochondria. Together, our findings show that modulation of mitochondrial S-glutathionylation signaling through Glrx2 augments resistance of male mice towards the development of NAFLD through preservation of mitochondrial redox buffering capacity. Additionally, our findings demonstrate the sex dimorphisms associated with the manifestation of NAFLD is related to the superior redox buffering capacity and modulation of the S-glutathionylome in hepatic mitochondria from female mice.

Promising tools into oxidative stress: A review of non-rodent model organisms

Oxidative stress is a crucial concept in redox biology, and significant progress has been made in recent years. Excessive levels of reactive oxygen species (ROS) can lead to oxidative damage, heightening vulnerability to various diseases. By contrast, ROS maintained within a moderate range plays a role in regulating normal physiological metabolism. Choosing suitable animal models in a complex research context is critical for enhancing research efficacy. While rodents are frequently utilized in medical experiments, they pose challenges such as high costs and ethical considerations. Alternatively, non-rodent model organisms like zebrafish, Drosophila, and C. elegans offer promising avenues into oxidative stress research. These organisms boast advantages such as their small size, high reproduction rate, availability for live imaging, and ease of gene manipulation. This review highlights advancements in the detection of oxidative stress using non-rodent models. The oxidative homeostasis regulatory pathway, Kelch-like ECH-associated protein 1-Nuclear factor erythroid 2-related factor 2 (Keap1-Nrf2), is systematically reviewed alongside multiple regulation of Nrf2-centered pathways in different organisms. Ultimately, this review conducts a comprehensive comparative analysis of different model organisms and further explores the combination of novel techniques with non-rodents. This review aims to summarize state-of-the-art findings in oxidative stress research using non-rodents and to delineate future directions.

Inonotus obliquus aqueous extract inhibits intestinal inflammation and insulin metabolism defects in Drosophila

In biomedical research, the fruit fly (Drosophila melanogaster) is among the most effective and flexible model organisms. Through the use of the Drosophila model, molecular mechanisms of human diseases can be investigated and candidate pharmaceuticals can be screened. White rot fungus Inonotus obliquus is a member of the family Hymenochaetaceae. Due to its multifaceted pharmacological effects, this fungus has been the subject of scientific investigation. Nevertheless, the precise mechanisms by which Inonotus obliquus treats diseases remain unclear. In this study, we prepared an aqueous extract derived from Inonotus obliquus and demonstrated that it effectively prevented the negative impacts of inflammatory agents on flies, including overproliferation and overdifferentiation of intestinal progenitor cells and decreased survival rate. Furthermore, elevated reactive oxygen species levels and cell death were alleviated by Inonotus obliquus aqueous extract, suggesting that this extract inhibited intestinal inflammation. Additionally, Inonotus obliquus aqueous extract had an impact on the insulin pathway, as it alleviated growth defects in flies that were fed a high-sugar diet and in chico mutants. In addition, we determined the composition of Inonotus obliquus aqueous extract and conducted a network pharmacology analysis in order to identify prospective key compounds and targets. In brief, Inonotus obliquus aqueous extract exhibited considerable potential as a therapeutic intervention for human diseases. Our research has established a foundational framework that supports the potential clinical implementation of Inonotus obliquus.

1G6-D7 Inhibits Homologous Recombination Repair by Targeting Extracellular HSP90α to Promote Apoptosis in Non-Small Cell Lung Cancer

Despite recent advances in treatment, non-small cell lung cancer (NSCLC) continues to have a high mortality rate. Currently, NSCLC pathogenesis requires further investigation, and therapeutic drugs are still under development. Homologous recombination repair (HRR) repairs severe DNA double-strand breaks. Homologous recombination repair deficiency (HRD) occurs when HRR is impaired and causes irreparable double-strand DNA damage, leading to genomic instability and increasing the risk of cancer development. Poly(ADP-ribose) polymerase (PARP) inhibitors can effectively treat HRD-positive tumors. Extracellular heat shock protein 90α (eHSP90α) is highly expressed in hypoxic environments and inhibits apoptosis, thereby increasing cellular tolerance. Here, we investigated the relationship between eHSP90α and HRR in NSCLC. DNA damage models were established in NSCLC cell lines (A549 and H1299). The activation of DNA damage and HRR markers, apoptosis, proliferation, and migration were investigated. In vivo tumor models were established using BALB/c nude mice and A549 cells. We found that human recombinant HSP90α stimulation further activated HRR and reduced DNA damage extent; however, eHSP90α monoclonal antibody, 1G6-D7, effectively inhibited HRR. HRR inhibition and increased apoptosis were observed after LRP1 knockdown; this effect could not be reversed with hrHSP90α addition. The combined use of 1G6-D7 and olaparib caused significant apoptosis and HRR inhibition in vitro and demonstrated promising anti-tumor effects in vivo. Extracellular HSP90α may be involved in HRR in NSCLC through LRP1. The combined use of 1G6-D7 and PARP inhibitors may exert anti-tumor effects by inhibiting DNA repair and further inducing apoptosis of NSCLC cells.

Sulfur-based fluorescent probes for biological analysis: A review

The widespread adoption of small-molecule fluorescence detection methodologies in scientific research and industrial contexts can be ascribed to their inherent merits, including elevated sensitivity, exceptional selectivity, real-time detection capabilities, and non-destructive characteristics. In recent years, there has been a growing focus on small-molecule fluorescent probes engineered with sulfur elements, aiming to detect a diverse array of biologically active species. This review presents a comprehensive survey of sulfur-based fluorescent probes published from 2017 to 2023. The diverse repertoire of recognition sites, including but not limited to N, N-dimethylthiocarbamyl, disulfides, thioether, sulfonyls and sulfoxides, thiourea, thioester, thioacetal and thioketal, sulfhydryl, phenothiazine, thioamide, and others, inherent in these sulfur-based probes markedly amplifies their capacity for detecting a broad spectrum of analytes, such as metal ions, reactive oxygen species, reactive sulfur species, reactive nitrogen species, proteins, and beyond. Owing to the individual disparities in the molecular structures of the probes, analogous recognition units may be employed to discern diverse substrates. Subsequent to this classification, the review provides a concise summary and introduction to the design and biological applications of these probe molecules. Lastly, drawing upon a synthesis of published works, the review engages in a discussion regarding the merits and drawbacks of these fluorescent probes, offering guidance for future endeavors.

THP as a sensor for the electrochemical detection of H2O2

Hydrogen peroxide (H2O2) detection is paramount in biological and clinical domains due to its pivotal role in various physiological and pathological processes. This molecule is a crucial metabolite and effector in cellular redox mechanisms, influencing diverse cellular signaling pathways and bolstering the body's defense mechanisms against infection and oxidative stress. Organic molecule-based electrodes present unique advantages such as operational versatility and scalability, rendering them attractive candidates for sensor development across diverse fields encompassing food safety, healthcare, and environmental monitoring. This study explores the electrochemical properties of a tris(3-hydroxypyridin-4-one) THP, which has been unexplored in electrochemical sensing. Leveraging THP's chelating properties, we aimed to develop an electrochemical probe for hydrogen peroxide detection. Our investigations reveal promising results, with the developed sensor exhibiting a low limit of detection (LOD) of 144 nM, underscoring its potential utility in sensitive and selective H2O2 detection applications. In addition, the new sensor was also tested on fetal bovine serum (FBS) to emphasize future applications on biological matrices. This research signifies a significant stride in advancing electrochemical sensor technologies for hydrogen peroxide detection with several novelties related to the usage of THP, such as high sensitivity and selectivity, performance in biological matrices, repeatability, stability, and reproducibility, economical and practical advantages. This research opens new avenues for enhanced biomedical diagnostics and therapeutic interventions.

Hydrogen peroxide modulates the expression of the target of rapamycin (TOR) and cell division in Arabidopsis thaliana

Hydrogen peroxide (H2O2) is naturally produced by plant cells during normal development and serves as a messenger that regulates cell metabolism. Despite its importance, the relationship between hydrogen peroxide and the target of rapamycin (TOR) pathway, as well as its impact on cell division, has been poorly analyzed. In this study, we explore the interaction of H2O2 with TOR, a serine/threonine protein kinase that plays a central role in controlling cell growth, size, and metabolism in Arabidopsis thaliana. By applying two concentrations of H2O2 exogenously (0.5 and 1 mM), we could correlate developmental traits, such as primary root growth, lateral root formation, and fresh weight, with the expression of the cell cycle gene CYCB1;1, as well as TOR expression. When assessing the expression of the ribosome biogenesis-related gene RPS27B, an increase of 94.34% was noted following exposure to 1 mM H2O2 treatment. This increase was suppressed by the TOR inhibitor torin 2. The elimination of H2O2 accumulation with ascorbic acid (AA) resulted in decreased cell division as well as TOR expression. The potential molecular mechanisms associated with the effects of H2O2 on the cell cycle and TOR expression in roots are discussed in the context of the results.

Accelerated In Vitro Oxidative Degradation Testing of Ultra-High Molecular Weight Polyethylene (UHMWPE)

Nonabsorbable polymers used in biomedical applications are assumed to be permanently stable based on short-term testing, but some may be susceptible to oxidative degradation over several years of implantation. Traditional in vitro oxidative degradation screenings employ hydrogen peroxide (H2O2) solutions. However, the inherent instability of H2O2 can compromise the consistency of oxidative conditions, especially over extended periods and at elevated temperatures used for accelerated testing. In this study, an automated reactive accelerated aging (aRAA) system, which integrates an electrochemical detection method and a feedback loop, was utilized to ensure precise control of H2O2 concentrations during polymer oxidative degradation testing. The reproducibility of the aRAA system was evaluated by comparing four identical setups. Its efficacy as an oxidation challenge was demonstrated on (i) medical-grade vitamin E (VE) blended ultra-high molecular weight polyethylene (UHMWPE) and (ii) highly crosslinked (HXL) UHMWPE as model materials. The aRAA-aged VE-UHMWPE and HXL-UHMWPE samples were also compared against samples aged via an existing accelerated aging standard, ASTM F2003-02(2022). Samples were analyzed using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to calculate their oxidation index per ASTM F2102-17. We observed that the aRAA system was more effective in oxidizing VE-UHMWPE and HXL-UHMWPE than the traditional ASTM F2003-02(2022) method. By providing a standardized and reliable approach to assess polymer oxidative degradation, the aRAA system could enhance the accuracy of long-term stability predictions for nonresorbable polymers in medical devices.

Unraveling the redox code to improve physiological research in human health and disease

Redox reactions, involving electron transfer, are critical to human physiology. However, progress in understanding redox metabolism is hindered by flawed analytical methods. This review highlights emerging techniques that promise to revolutionize redox research, enhancing our comprehension of human health and disease. Oxygen, vital for aerobic metabolism, also produces reactive oxygen species (ROS), such as superoxide and hydrogen peroxide. While historically seen as harmful, ROS at low concentrations are now recognized as key regulators of cell signaling. A balance between ROS and antioxidants, known as redox balance, is crucial, and deviations can lead to oxidative stress. Recent studies have distinguished beneficial "oxidative eustress" from harmful "oxidative distress." New techniques, such as advanced mass spectrometry and high-throughput immunoassays, offer improved accuracy in measuring redox states and oxidative damage. These advancements are pivotal for understanding redox signaling, cysteine oxidation, and their implications for disease. Looking ahead, the development of precision redox medicine could lead to better treatments for oxidative stress-related diseases and foster interventions promoting health.

Sensor systems of KEAP1 uniquely detecting oxidative and electrophilic stresses separately In vivo

In the KEAP1-NRF2 stress response system, KEAP1 acts as a sensor for oxidative and electrophilic stresses through formation of S-S bond and C-S bond, respectively. Of the many questions left related to the sensor activity, following three appear important; whether these KEAP1 sensor systems are operating in vivo, whether oxidative and electrophilic stresses are sensed by the similar or distinct systems, and how KEAP1 equips highly sensitive mechanisms detecting oxidative and electrophilic stresses in vivo. To address these questions, we conducted a series of analyses utilizing KEAP1-cysteine substitution mutant mice, conditional selenocysteine-tRNA (Trsp) knockout mice, and human cohort whole genome sequence (WGS) data. Firstly, the Trsp-knockout provokes severe deficiency of selenoproteins and compensatory activation of NRF2. However, mice lacking homozygously a pair of critical oxidative stress sensor cysteine residues of KEAP1 fail to activate NRF2 in the Trsp-knockout livers. Secondly, this study provides evidence for the differential utilization of KEAP1 sensors for oxidative and electrophilic stresses in vivo. Thirdly, theoretical calculations show that the KEAP1 dimer equips quite sensitive sensor machinery in which modification of a single molecule of KEAP1 within the dimer is sufficient to affect the activity. WGS examinations of rare variants identified seven non-synonymous variants in the oxidative stress sensors in human KEAP1, while no variant was found in electrophilic sensor cysteine residues, supporting the fail-safe nature of the KEAP1 oxidative stress sensor activity. These results provide valuable information for our understanding how mammals respond to oxidative and electrophilic stresses efficiently.

Early Cardiac Ischemia-Reperfusion Injury: Interactions of Autophagy with Galectin-3 and Oxidative Stress

Background: Cardiovascular diseases are the leading cause of death worldwide, including the United Arab Emirates. Ischemia-reperfusion (IR) injury results in the death of cardiac myocytes that were viable immediately before myocardial reperfusion. We aim to investigate the role of galectin-3 (Gal-3) in autophagy during ischemia-reperfusion injuries. Methods: Male C57B6/J and Gal-3 knockout (KO) mice were used for the murine model of IR injury. Heart samples and serum were collected 24 h post-IR and were processed for immunohistochemical and immunofluorescent labeling and an enzyme-linked immunosorbent assay. Results: There was a significant increase in left ventricle (LV) concentrations of Gal-3 in Gal-3 wild-type mice compared to sham mice. There were significantly higher concentrations of LV autophagy proteins and phospho-AMPK in IR Gal-3 KO mice than in IR Gal-3 wild-type mice, compared to lower concentrations of LV phospho-mTOR and p62 in IR Gal-3 KO than in IR wild-type mice. Antioxidant activities were higher in the LVs of IR Gal-3 wild-type mice, while oxidative stress was higher in the LVs of IR Gal-3 KO mice. Conclusions: Our study supports the interaction of Gal-3 with autophagy proteins, oxidative stress, and antioxidant proteins and demonstrates that the absence of Gal-3 can enhance autophagy in the heart after IR injury.

The Role of Oxidative Stress and the Potential Therapeutic Benefits of Aronia melanocarpa Supplementation in Obstructive Sleep Apnea Syndrome: A Comprehensive Literature Review

Obstructive sleep apnea (OSA) is a sleep disorder characterized by repeated episodes of apnea and hypopnea, leading to inflammation and oxidative stress that contribute to numerous health complications, including cardiovascular diseases. Continuous positive airway pressure (CPAP) is a standard for treating OSA and is effective in reducing inflammation and oxidative stress. Aronia melanocarpa (a black chokeberry), a deciduous shrub belonging to the Rosaceae family and native to eastern North America that is rich in polyphenols, has garnered attention for its therapeutic potential due to its ability to neutralize reactive oxygen species (ROS) and modulate inflammatory pathways, such as NF-κB. This review supports the hypothesis that combining CPAP with black chokeberry supplementation might provide a more comprehensive approach to treating OSA, reducing the risk of health complications by further reducing oxidative stress. In conclusion, Aronia melanocarpa has potential benefits as an adjunct therapy in the treatment of OSA, enhancing overall health and well-being. This review compiles the latest scientific findings on the benefits of black chokeberry supplementation, its application in OSA treatment, and its potential use in the treatment of other conditions linked to oxidative stress.

Luminescent Ln(III)-Metallopeptide Sensors for Monitoring Pseudomonas aeruginosa Elastase B Activity in Complex Biological Media

The detection and monitoring of Pseudomonas aeruginosa and its virulence factors, such as the LasB protease, are crucial for managing bacterial infections. Traditional fluorescent sensors for this protease face limitations in bacterial cultures due to interference from pigments like pyoverdine secreted by this opportunistic pathogen. We report here a Ln(III)-metallopeptide that combines a DO3A-Ln(III) complex and a sensitizing unit via a short peptide sequence as a simple, tunable, and selective probe for detecting P. aeruginosa's LasB. The probe's luminescence switches off in the presence of P. aeruginosa's secretome due to LasB cleavage but remains stable in other bacterial environments, such as non-LasB-secreting P. aeruginosa strains or E. coli cultures. It also resists degradation by other proteases, like human leukocyte elastase and trypsin, and remains stable in the presence of bioanalytes related to P. aeruginosa infections, such as glutathione, H2O2, and pyocyanin, and in complex media like FBS. Importantly, time-gated experiments completely remove the background fluorescence of P. aeruginosa pigments, thus demonstrating the potential of the developed Ln(III)-metallopeptide for real-time monitoring of LasB activity in bacterial cultures.

[Role of Mitochondria in Ferroptosis and Its Relationship to Tumors]

Ferroptosis is a recently discovered form of cell death that is distinct from apoptosis, characterized primarily by the accumulation of intracellular iron and increased levels of lipid peroxidation. Resistance of tumor cells to ferroptosis can promote tumorigenesis and tumor progression. Various compounds can influence tumor development by triggering ferroptosis. Ferroptosis involves complex regulatory mechanisms, with mitochondria serving as both an iron storage and metabolic center, playing a crucial regulatory role in ferroptosis. This review discusses ferroptosis and its three stages and the role of ferroptosis in tumorigenesis, progression, and treatment, as well as the regulatory mechanisms of mitochondria in ferroptosis.
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Cleavage of a Peroxide Bond via a Dual Attack by Functional Mimics of Glutathione Peroxidase

Nonmetal-containing peroxidase enzymes, including glutathione peroxidase (GPx), and peroxiredoxins, control cellular redox levels by catalyzing the reduction of H2O2. The remarkably higher reactivity of GPx enzyme as compared to the fully dissociated synthetic selenolate/thiolate molecule is probably due to the dual-attack on the peroxide bond (HO1-O2H) by the enzyme; The first one is a nucleophilic attack of the selenolate/thiolate moiety to O1 atom and the second attack at the O2 atom of the peroxide bond by the acidic "parked proton" from Trp or His residue present at the enzyme's active site, leading to the facile cleavage of O-O bond. Herein, we report two synthetic compounds (1 and 2), having a selenolate (Se-) and a proton donor (imidazolium or -COOH group) moieties, which showed excellent GPx-like activity via dual-attack on the peroxide bond. The combined effect of selenolate moiety that donates electrons to the antibonding (σ*) orbital of O1-O2 bond and the imidazolium or carboxylic acid moiety at the side chain that forms a strong H-bonding with the O2 atom facilitates O-O bond cleavage of H2O2 more efficiently. 1 and 2 exhibit remarkable ability in protecting Cu(I)-complex [TpmCu(CH3CN)]+ (9) against H2O2 by acting as a sacrificial antioxidant, thereby preventing metal-mediated ROS production.

Shattering the Water Window: Comprehensive Mapping of Faradaic Reactions on Bioelectronics Electrodes

It is generally accepted that for safe use of neural interface electrodes, irreversible faradaic reactions should be avoided in favor of capacitive charge injection. However, in some cases, faradaic reactions can be desirable for controlling specific (electro)physiological outcomes or for biosensing purposes. This study aims to systematically map the basic faradaic reactions occurring at bioelectronic electrode interfaces. We analyze archetypical platinum-iridium (PtIr), the most commonly used electrode material in biomedical implants. By providing a detailed guide to these reactions and the factors that influence them, we offer a valuable resource for researchers seeking to suppress or exploit faradaic reactions in various electrode materials. We employed a combination of electrochemical techniques and direct quantification methods, including amperometric, potentiometric, and spectrophotometric assays, to measure O2, H2, pH, H2O2, Cl2/OCl-, and soluble platinum and iridium ions. We compared phosphate-buffered saline (PBS) with an unbuffered electrolyte and complex cell culture media containing proteins. Our results reveal that the "water window"─the potential range without significant water electrolysis─varies depending on the electrolyte used. In the culture medium that is rich with redox-active species, a window of potentials where no faradaic process occurs essentially does not exist. Under cathodic polarizations, significant pH increases (alkalization) were observed, while anodic water splitting competes with other processes in media, preventing prevalent acidification. We quantified the oxygen reduction reaction and accumulation of H2O2 as a byproduct. PtIr efficiently deoxygenates the electrolyte under low cathodic polarizations, generating local hypoxia. Under anodic polarizations, chloride oxidation competes with oxygen evolution, producing relatively high and cytotoxic concentrations of hypochlorite (OCl-) under certain conditions. These oxidative processes occur alongside PtIr dissolution through the formation of soluble salts. Our findings indicate that the conventional understanding of the water window is an oversimplification. Important faradaic reactions, such as oxygen reduction and chloride oxidation, occur within or near the edges of the water window. Furthermore, the definition of the water window significantly depends on the electrolyte composition, with PBS yielding different results compared with culture media.

Inflammation environment-adaptive matrix confinement for three-dimensional modulation of macrophages

The balance of macrophages in immune reactions is crucial for tissue repair. Despite some studies on responsive surfaces for immunomodulation regulation of macrophage phenotypes via external stimuli, 2D and manual interventions are limited. Herein, to address these limitations, we developed an inflammation environment-responsive macrophage-laden hydrogel-filled scaffold for investigating the impact of matrix confinement on macrophage phenotypes adaptively. We fabricated gelatin scaffolds with a controllable pore size and found that macrophages within smaller pores tended to have an anti-inflammation phenotype. We prepared poly(vinyl alcohol) (PVA)-based hydrogels crosslinked with phenylboronic acid (PBA)-based linkers. The hydrogels possessed shear-thinning, cell-loading, and ROS-sensitive-degradation abilities. Subsequently, a macrophage-laden hydrogel-filled scaffold was fabricated by filling the hydrogels into the porous scaffold under vacuum. With the degradation of the hydrogels under the overexpression of ROS in an inflammation environment, the macrophages were transferred from a state with strong matrix confinement to that with a weaker one. Meanwhile, with the change in matrix confinement, the macrophages upregulated the expressions of Arg-1 and IL-10 and downregulated the expressions of IL-1β, TNF-α, and IL-6, indicating polarization toward the anti-inflammatory phenotype. The inflammation environment-adaptive modulation of macrophage phenotypes in 3D provides a smart and biomimetic strategy for immunomodulation and regenerative medicine.

Effects of microbe-derived antioxidants on growth performance, hepatic oxidative stress, mitochondrial function and cell apoptosis in weaning piglets

BACKGROUND

Weaning causes redox dyshomeostasis in piglets, which leads to hepatic oxidative damage. Microbe-derived antioxidants (MA) have great potential for anti-oxidation. This study aimed to investigate changes in hepatic redox system, mitochondrial function and apoptosis after weaning, and effects of MA on growth performance and liver health in weaning piglets.

METHODS

This study consisted of 2 experiments. In the both experiments, piglets were weaned at 21 days of age. In Exp. 1, at 21 (W0), 22 (W1), 25 (W4), 28 (W7), and 35 (W14) days of age, 6 piglets were slaughtered at each timepoint. In Exp. 2, piglets were divided into 2 groups: one received MA gavage (MA) and the other received saline gavage (CON). At 25 days of age, 6 piglets from each group were sacrificed.

RESULTS

In Exp. 1, weaning caused growth inhibition and liver developmental retardation from W0 to W4. The mRNA sequencing between W0 and W4 revealed that pathways related to "regulation of apoptotic process" and "reactive oxygen species metabolic process" were enriched. Further study showed that weaning led to higher hepatic content of reactive oxygen species (ROS), H2O2 and O2-. Weaning enhanced mitochondrial fission and suppressed their fusion, activated mitophagy, thus triggering cell apoptosis. In Exp. 2, MA improved growth performance of piglets with higher average daily gain (ADG) and average daily feed intake (ADFI). The hepatic ROS, as well as products of oxidative damage malonaldehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the MA group decreased significantly than that of the CON group. The MA elevated mitochondrial membrane potential, increased activity of mitochondrial respiratory chain complexes (MRC) I and IV, enhanced mitochondrial fusion and reduced mitophagy, thus decreasing cell apoptosis.

CONCLUSIONS

The present study showed that MA improved the growth performance of weaning piglets and reversed weaning-induced oxidative damage, mitochondrial dysfunction, and apoptosis. Our results suggested that MA had promising prospects for maintaining liver health in weaning piglets and provided a reference for studies of liver diseases in humans.

Permeation mechanisms of hydrogen peroxide and water through Plasma Membrane Intrinsic Protein aquaporins

Hydrogen peroxide (H2O2) transport by aquaporins (AQP) is a critical feature for cellular redox signaling. However, the H2O2 permeation mechanism through these channels remains poorly understood. Through functional assays, two Plasma membrane Intrinsic Protein (PIP) AQP from Medicago truncatula, MtPIP2;2 and MtPIP2;3 have been identified as pH-gated channels capable of facilitating the permeation of both water (H2O) and H2O2. Employing a combination of unbiased and enhanced sampling molecular dynamics simulations, we investigated the key barriers and translocation mechanisms governing H2O2 permeation through these AQP in both open and closed conformational states. Our findings reveal that both H2O and H2O2 encounter their primary permeation barrier within the selectivity filter (SF) region of MtPIP2;3. In addition to the SF barrier, a second energetic barrier at the NPA (asparagine-proline-alanine) region that is more restrictive for the passage of H2O2 than for H2O, was found. This behavior can be attributed to a dissimilar geometric arrangement and hydrogen bonding profile between both molecules in this area. Collectively, these findings suggest mechanistic heterogeneity in H2O and H2O2 permeation through PIPs.

Inter-tissue differences in oxidative stress susceptibility reveal a less stable endothelial barrier in the brain than in the retina

Oxidative stress can impair the endothelial barrier and thereby enable autoantibody migration in Neuromyelitis optica spectrum disorder (NMOSD). Tissue-specific vulnerability to autoantibody-mediated damage could be explained by a differential, tissue-dependent endothelial susceptibility to oxidative stress. In this study, we aim to investigate the barrier integrity and complement profiles of brain and retinal endothelial cells under oxygen-induced oxidative stress to address the question of whether the pathomechanism of NMOSD preferentially affects the brain or the retina. Primary human brain microvascular endothelial cells (HBMEC) and primary human retinal endothelial cells (HREC) were cultivated at different cell densities (2.5*104 to 2*105 cells/cm2) for real-time cell analysis. Both cell types were exposed to 100, 500 and 2500 μM H2O2. Immunostaining (CD31, VE-cadherin, ZO-1) and Western blot, as well as complement protein secretion using multiplex ELISA were performed. HBMEC and HREC cell growth phases were cell type-specific. While HBMEC cell growth could be categorized into an initial peak, proliferation phase, plateau phase, and barrier breakdown phase, HREC showed no proliferation phase, but entered the plateau phase immediately after an initial peak. The plateau phase was 7 h shorter in HREC. Both cell types displayed a short-term, dose-dependent adaptive response to H2O2. Remarkably, at 100 μM H2O2, the transcellular resistance of HBMEC exceeded that of untreated cells. 500 μM H2O2 exerted a more disruptive effect on the HBMEC transcellular resistance than on HREC. Both cell types secreted complement factors H (FH) and I (FI), with FH secretion remaining stable after 2 h, but FI secretion decreasing at higher H2O2 concentrations. The observed differences in resistance to oxidative stress between primary brain and retinal endothelial cells may have implications for further studies of NMOSD and other autoimmune diseases affecting the eye and brain. These findings may open novel perspectives for the understanding and treatment of such diseases.

AQP1 differentially orchestrates endothelial cell senescence

Accumulation of senescent endothelial cells (ECs) with age is a pivotal driver of cardiovascular diseases in aging. However, little is known about the mechanisms and signaling pathways that regulate EC senescence. In this report, we delineate a previously unrecognized role of aquaporin 1 (AQP1) in orchestrating extracellular hydrogen peroxide (H2O2)-induced cellular senescence in aortic ECs. Our findings underscore AQP1's differential impact on senescence hallmarks, including cell-cycle arrest, senescence-associated secretory phenotype (SASP), and DNA damage responses, intricately regulating angiogenesis. In proliferating ECs, AQP1 is crucial for maintaining angiogenic capacity, whereas disruption of AQP1 induces morphological and mitochondrial alterations, culminating in senescence and impaired angiogenesis. Conversely, Aqp1 knockdown or selective blockade of AQP1 in senescent ECs rescues the excess H2O2-induced cellular senescence phenotype and metabolic dysfunction, thereby ameliorating intrinsic angiogenic incompetence. Mechanistically, AQP1 facilitates H2O2 transmembrane transport, exacerbating oxidant-sensitive kinases CaMKII-AMPK. This process suppresses HDAC4 translocation, consequently de-repressing Mef2A-eNOS signaling in proliferating ECs. However, in senescent ECs, AQP1 overexpression is linked to preserved HDAC4-Mef2A complex and downregulation of eNOS signaling. Together, our studies identify AQP1 as a novel epigenetic regulator of HDAC4-Mef2A-dependent EC senescence and angiogenic potential, highlighting its potential as a therapeutic target for antagonizing age-related cardiovascular diseases.

NADPH oxidases in healthy white adipose tissue and in obesity: function, regulation, and clinical implications

Reactive oxygen species, when produced in a controlled manner, are physiological modulators of healthy white adipose tissue (WAT) expansion and metabolic function. By contrast, unbridled production of oxidants is associated with pathological WAT expansion and the establishment of metabolic dysfunctions, most notably insulin resistance and type 2 diabetes mellitus. NADPH oxidases (NOXs) produce oxidants in an orderly fashion and are present in adipocytes and in other diverse WAT-constituent cell types. Recent studies have established several links between aberrant NOX-derived oxidant production, adiposity, and metabolic homeostasis. The objective of this review is to highlight the physiological roles attributed to diverse NOX isoforms in healthy WAT and summarize current knowledge of the metabolic consequences related to perturbations in their adequate oxidant production. We detail WAT-related alterations in preclinical investigations conducted in NOX-deficient murine models. In addition, we review clinical studies that have employed NOX inhibitors and currently available data related to human NOX mutations in metabolic disturbances. Future investigations aimed at understanding the integration of NOX-derived oxidants in the regulation of the WAT cellular redox network are essential for designing successful redox-related precision therapies to curb obesity and attenuate obesity-associated metabolic pathologies.

Ganweikang extract protects hepatocytes from oxidative injury by activating Nrf2/HO-1 and MAPKs pathways

Ganweikang tablet (GWK) is a traditional Chinese prescription and has been clinically used in treating liver diseases for decades. Although GWK has been shown to exert potential therapeutic effect for hepatotoxicity protection, the underlying biological mechanisms are still not well clarified. In the present study, the compositional analysis of GWK was performed by HPLC analysis, and the hepato-protective effects of GWK were assessed in H2O2-stimulated acute oxidative injured HL-7702 hepatocytes in vitro. As a result, 7 components in GWK were quantified to be 0.06 ± 0.01% (calycosin), 0.46 ± 0.02% (calycosin-7-glucoside), 0.13 ± 0.01% (liquiritin), 0.17 ± 0.02% (glycyrrhizic acid), 0.45 ± 0.02% (forsythoside A), 0.07 ± 0.01% (5-O-methylvisammioside) and 0.45 ± 0.02% (forsythin), respectively. Furthermore, GWK (100, 200 and 400 μg/mL, 24 h) dose-dependently alleviated HL-7702 hepatocytes from H2O2 (200 μM, 2 h)-induced cell apoptosis by decreasing the intracellular reactive oxygen species (ROS) generation and malondialdehyde (MDA) level, as well as the cellular aminotransferases (ALT and AST) activities. GWK increased the expressions of HO-1, NQO1 and Nrf2, while suppressing the expression of KEAP1 in H2O2-stimulated HL-7702 cells. A specific Nrf2 inhibitor, ML385, was further employed to investigate the regulation of Nrf2 in HL-7702 cells stimulated by H2O2. In addition, the activation of MAPKs (JUN, ERK and p38) was simultaneously detected in H2O2-stimulated HL-7702 cells. In conclusion, GWK exerted potential therapeutic effect to protect hepatocytes from acute oxidative injury through activating the Nrf2/HO-1 and MAPKs pathways.

Self-activated hydrogel cascade reactor integrated with glucose oxidase and silver nanoparticle for enhanced treatment of bacterial infection

The recognition of silver nanoparticles (AgNPs) as a nanozyme with peroxidase-like activity has offered a promising solution to address the challenges of bacterial resistance and argyria risk. However, the catalytic efficacy of AgNPs is limited by the need for a strong acidic environment and high concentrations of hydrogen peroxide (H2O2). In this work, we developed a self-activated hydrogel cascade reactor (AUGP) for enhanced treatment of bacterial infection. The AUGP integrates the properties of glucose oxidase (GOx) and polyacrylamide (pAAm) hydrogel microsphere. The confinement effect of pAAm hydrogel microsphere enables glucose oxidation to occur in a confined space, which creates an acidic environment to activate AgNPs activity, initiating the cascade reaction between GOx and AgNPs. Meanwhile, the confinement effect facilitates the accumulation of a high local concentration of H2O2, allowing AUGP to generate hydroxyl radicals (•OH) without the need for external H2O2. Additionally, the release of Ag+ from AUGP is achieved upon the generation of •OH. The synergistic action of Ag+ and •OH confers exceptional antibacterial efficacy to AUGP. Importantly, the etching effect of H2O2 ensures the absence of any residual AgNPs, reducing the risk of argyria. In vivo studies validated the efficacy of AUGP in wound disinfection with minimal toxicity.

Telomere length exhibits inverse association with migraine among Americans aged 20-50 years, without implications beyond age 50: a cross-sectional study

Migraine, common in individuals under 50 years, is linked to oxidative stress. The association between telomere length shortening and migraine, along with potential age-related influences, has not been comprehensively studied. This cross-sectional study included data from 6169 participants in the National Health and Nutrition Survey (NHANES) from 1999 to 2002, encompassing information on peripheral blood leukocyte telomere length, severe headache or migraine, and potential confounders. Stratifying by age (20-50 years, > 50 years), we employed multivariable logistic regression, restricted cubic splines and interaction test to investigate age-influenced telomere length in relation to migraine. In participants aged 20-50 years, the odds ratio (OR) for migraine in the shortest telomere length group T1 (0.39-0.89) was 1.35 (95% confidence interval [95% CI] 1.01, 1.79) compared to the longest group T3 (1.10-9.42), whereas in those aged > 50 years, the OR of T1 was 0.93 (95% CI 0.60, 1.43). Additionally, telomere length and age interacted in the development of migraine (p for interaction: 0.010). In individuals aged 20-50, an L-shaped relationship was found between telomere length and migraine, with an inflection point at 1.02T/S ratio. The OR was 9.34 (95% CI 1.56, 55.99) for telomere lengths < 1.02T/S ratio. These findings suggest age influences the association between telomere length and migraine in U.S. adults.