Nitrative and oxidative stress in toxicology and disease

A workflow for human health hazard evaluation using transcriptomic data and Key Characteristics-based gene sets

Key characteristics (KCs) are properties of chemicals that are associated with different types of human health hazards. KCs are used for systematic reviews in support of hazard identification. Transcriptomic data are a rich source of mechanistic data and are frequently interpreted through "enriched" pathways/gene sets. Such analyses may be challenging to interpret in regulatory science because of redundancy among pathways, complex data analyses, and unclear relevance to hazard identification. We hypothesized that by cross-mapping pathways/gene sets and KCs, the interpretability of transcriptomic data can be improved. We summarized 72 published KCs across 7 hazard traits into 34 umbrella KC terms. Gene sets from Reactome and Kyoto Encyclopedia of Genes and Genomes (KEGG) were mapped to these, resulting in "KC gene sets." These sets exhibit minimal overlap and vary in the number of genes. Comparisons of the same KC gene sets mapped from Reactome and KEGG revealed low similarity, indicating complementarity. Performance of these KC gene sets was tested using publicly available transcriptomic datasets of chemicals with known organ-specific toxicity: benzene and 2,3,7,8-tetrachlorodibenzo-p-dioxin tested in mouse liver and drugs sunitinib and amoxicillin tested in human-induced pluripotent stem cell-derived cardiomyocytes. We found that KC terms related to the mechanisms affected by tested compounds were highly enriched, while the negative control (amoxicillin) showed limited enrichment with marginal significance. This study's impact is in presenting a computational approach based on KCs for the analysis of toxicogenomic data and facilitating transparent interpretation of these data in the process of chemical hazard identification.

Exposure to organophosphates, pyrethroids, neonicotinoids, and pentachlorophenol: Spatial variations in urinary biomarkers and associations with oxidative stress based on a repeated-measure study

It is important to identify priority regions regarding contaminant exposure, especially for environmental epidemiological studies. Whereas very few studies explored spatial variations in concentrations of multiple insecticide metabolites in the general population, as well as their relationship with oxidative stress biomarkers (OSBs). We determined related target analytes in urine samples (n = 850) from 425 healthy adults in six cities of China during both autumn and winter. Eight organophosphorus metabolites (mOPPs), three pyrethroid metabolites (mPYRs), nine neonicotinoid insecticide metabolites (mNNIs), and pentachlorophenol (PCP) were detected in the urine samples. Additionally, linear mixed-effects model and weighted quantile sum model were used to assess the individual and combined effects of the insecticide exposure on selected OSBs. Altogether, 17 out of the 21 analytes were widely detected (73.1-100%). The median specific gravity (SG)-adjusted concentrations for the mOPPs, mPYRs, mNNIs, and PCP were 1.17-4.85, 0.45-0.79, 0.09-1.07, and 0.38 ng/mL, respectively. The mOPPs in Lanzhou (northwest China), mPYRs and mNNIs in Dalian (northeast China), and PCP in Chengdu (southwest China) had the highest concentrations among the six cities. The concentrations of the mNNIs and PCP in urban areas were significantly higher than those in rural areas, while the concentrations of some mOPPs and mPYRs were higher in rural areas. The concentrations of most analytes were higher in autumn than in winter. Hazard quotient of >1 for chlorpyrifos was observed in 9.2% of the study participants, suggested a potential health risk, while the estimated daily intake values of the other analytes were lower than their chronic reference doses. Many of the insecticide exposure biomarkers were significantly associated with increased OSBs; among them, each interquartile range-fold increase in the insecticide exposure biomarkers was associated with 5.4-19.0%, 4.6-19.4%, and 12.4-83.3% increase in 8-hydroxy-2'-deoxyguanosine, 8-hydroxy guanosine, and 4-hydroxy-2-nonenal-mercapturic acid, respectively. P-Nitrophenol was the main contributor in the association with the increased OSBs. This study found significant variations in insecticide exposure levels among different regions and seasons. The exposure level of chlorpyrifos suggested a potential health risk, and the insecticide mixture exposure was significantly associated with increased OSBs. Further risk assessments are warranted and control measures in the insecticide use are needed to mitigate the potential health risks.

AKR1C1 protects against intracerebral hemorrhage by suppressing neuronal cell death via the P53/SLC7A11/GPX4 axis

Intracerebral hemorrhage (ICH) is associated with the highest rates of mortality and residual disability. To date, effective treatments to delay or prevent ICH are still lacking. Multiple forms of neuronal cell death have been discovered following ICH, including apoptosis, necrosis, autophagy, and ferroptosis. Aldo-keto reductase family 1 member C1 (AKR1C1) has been identified to act as a protective factor in ferroptosis. However, whether AKR1C1 was involved in the development of ICH was unknown. In this study, the left cerebral striatum of the Sprague-Dawley rat was injected with collagenase type IV to induce an in vivo model. Primary rat cortical neurons treated with oxygen hemoglobin (OxyHb) were applied to as an in vitro model. AKR1C1 was found to be downregulated and immunoreactivity colocalized with NeuN-positive neurons in the perihematomal region. Rats injected with lentiviral particles overexpressing AKR1C1 showed the reduction of cerebral hematoma and the remission of blood-brain barrier disruption. Moreover, AKR1C1 upregulation repressed cell apoptosis and ferroptosis induced by ICH through downregulating the expression of pro-apoptotic factors, inhibiting iron accumulation and lipid peroxidation, along with increasing the expression of solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4). The results of in vitro assays were consistent with results from the in vivo. Mechanistically, P53 overexpression augmented the cellular damage in OxyHb-stimulated neurons when AKR1C1 was overexpressed. Taken together, AKR1C1 improves ICH injury by inhibiting neuronal cell death via negatively regulating P53 expression and affecting the SLC7A11/GPX4 pathway.

Aryl hydrocarbon receptor (AHR) and nuclear factor erythroid-derived 2-like 2 (NRF2): An important crosstalk in the gut-liver axis

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor, mainly involved in detoxification. However, in the intestine, metabolites derived from the diet, which are converted by a wide range of bacteria can also activate the AHR. This intestinal AHR activation plays a key role in maintaining the gut barrier by, for example, upregulating antimicrobial peptides and anti-inflammatory cytokines. Since the gut barrier influences the gut-liver axis by regulating the leaking of metabolites, bacteria, and endotoxins into circulation and particularly into the liver, the AHR is a key factor in the gut-liver axis. Vice versa, certain liver pathologies also influence the gut microbiome, thereby altering bacteria-derived activation of the AHR. Additionally, bile acids can impact the gut via the liver and thereby also affect the AHR. The aryl hydrocarbon receptor (AHR) interacts with several molecular factors, one of which is the nuclear factor erythroid-derived 2-like 2 (NRF2), a transcription factor primarily associated with regulating antioxidant stress responses. The interplay between AHR and NRF2 has been investigated in the context of various diseases; this review highlights the significance of this interaction within the framework of the gut-liver axis.

Oligomeric proanthocyanidin ameliorates sepsis-associated renal tubular injury: involvement of oxidative stress, inflammation, PI3K/AKT and NFκB signaling pathways

Sepsis is a potentially fatal infectious disease that easily causes shock and numerous organ failures. The kidney is one of the most susceptible to injury. Early intervention and renal protection significantly minimize patient mortality. Oligomeric proanthocyanidin (OPC), a naturally occurring plant compound, has a high potential for renal protection. This study was aimed at exploring the potential renoprotective role of OPC in sepsis-related renal tubular injury. C57/B6 mice were intraperitoneally injected with lipopolysaccharide (LPS) to simulate sepsis-related acute kidney injury in vivo. Renal function and pathology were assessed. RNA sequencing examined OPC mechanisms against LPS-induced renal injury. Oxidative stress indicators and inflammatory cytokines in blood serum and renal tissues were evaluated. In vitro, MTT assays assess cell viability. Apoptosis cells were detected using Hoechst 33342 and propidium iodide staining. Western blot assessed PI3K/AKT and NFκB signaling pathway proteins. OPC reduced LPS-induced renal tubular injury, improved renal functions and pathological changes, restored glutathione content, superoxide dismutase activity, and catalase activity, inhibited malondialdehyde overproduction, and suppressed LPS-induced overproduction of pro-inflammatory cytokines and the decline of anti-inflammatory cytokines. OPC attenuated LPS-induced cell morphological injury, reduced cell viability loss, and recovered the changes in proteins involved in PI3K/AKT and NFκB signaling pathways in MTEC cells. OPC protects against LPSinduced renal tubular injury by counteracting oxidative stress, inhibiting inflammatory responses, activating the PI3K/AKT signaling pathway, and inhibiting the NFκB signaling pathway. It may provide a viable solution to lessen renal injury in patients with sepsis.

Unraveling the ozone impact and oxidative stress on the nervous system

Ozone (O₃), a potent oxidant, can penetrate the body through breathing, generating reactive oxygen species (ROS) and triggering inflammatory processes. Oxidative stress, an imbalance between the production of ROS and the body's antioxidant capacity, plays a crucial role in the pathophysiology of various neurodegenerative diseases. This phenomenon can negatively impact the Central Nervous System (CNS), inducing structural and functional alterations that contribute to the development of neurological pathologies. This review examines how O₃-induced oxidative stress affects the nervous system by analyzing existing literature on the involved molecular mechanisms and potential antioxidant systems to mitigate its effects. Through a comprehensive review of experimental studies, our objective is to shed light on the interaction between O₃ and the nervous system, as well as its signaling pathways and altered genes, providing a foundation for future research in this field. Several studies have demonstrated that prolonged exposure to O₃ leads to increased expression of reactive oxygen species, causing alterations in the blood-brain barrier and damage to astrocytes and microglia. These effects can lead to an increase in the production of proinflammatory cytokines, neurotoxins, and genes, exacerbating neuronal damage and accelerating the progression of neurodegenerative diseases such as Alzheimer's, Parkinson's, and other neurological disorders. The results of this review suggest that exposure to O₃ may induce oxidative damage to the nervous system, which could have significant implications for public health.

Inside the genome: understanding genetic influences on oxidative stress

Genetics is a key factor that governs the susceptibility to oxidative stress. In the body, oxidative burden is regulated by the balance between the prooxidant genes that orchestrate processes that produce oxidant species, while the antioxidant genes aid those involved in scavenging these species. Together, the two components aid in maintaining the oxidative balance in the body. Genetic variations can influence the expression and activity of the encoded proteins which can then affect their efficiency in regulating redox processes, thereby increasing the risk of oxidative stress. This review studies single nucleotide polymorphisms (SNPs) that bear relevance to oxidative stress by exploring the variations in the prooxidant genes, such as XDH, CYBA, CYP1A1, PTGS2, NOS, and MAO and antioxidant genes including SOD, CAT, GPX, GSS, GLUL, GSR, GSTM1, GSTM5, GSTP1, TXN and HMOX1. Early identification of individuals at the increased risk of oxidative stress is possible from the assessment of sequence of these genes. Integrating genetic insights into oxidative stress management measures can pave the way for personalized medicine that tailors' healthcare approaches to individual genetic profiles. Effective genetic assessment along with routine quantification of biological markers can improve and monitor treatment strategies, enhancing mitigation approaches that maintain cellular health and promote longevity.

The Effect of Propofol on the Hippocampus in Chronic Cerebral Hypoxia in a Rat Model Through Klotho Regulation

BACKGROUND/AIM

Chronic cerebral hypoxia often leads to brain damage and inflammation. Propofol is suggested to have neuroprotective effects under anaesthesia.

MATERIALS AND METHODS

This study used rat models with carotid artery coarctation or closure. Four groups of rats were compared: a control group, a propofol-treated group, a group with bilateral common carotid artery blockage (BCAO), and a BCAO group treated with propofol post-surgery.

RESULTS

The Morris water maze test indicated cognitive impairment in BCAO rats, which also showed hippocampal structure changes, oxidative stress markers alteration, and reduced Klotho expression. Propofol treatment post-BCAO surgery improved these outcomes, suggesting its potential in mitigating chronic cerebral hypoxia effects.

CONCLUSION

Propofol may increase klotho levels and reduce apoptosis and inflammation linked to oxidative stress in cognitively impaired mice.

Exploring sulforaphane as neurotherapeutic: targeting Nrf2-Keap & Nf-Kb pathway crosstalk in ASD

Autism spectrum disorders (ASD) are a family of complex neurodevelopmental disorders, characterized mainly through deficits in social behavior and communication. While the causes giving rise to autistic symptoms are numerous and varied, the treatment options and therapeutic avenues are still severely limited. Nevertheless, a number of signalling pathways have been implicated in the pathogenesis of the disease, and targeting these pathways might provide insight into potential treatments and future strategies. Importantly, alterations in inflammation, oxidative stress, and mitochondrial dysfunction have been noted in the brains of ASD patients, and among the pathways involved in these processes is the Nrf2 cascade. This particular pathway has been hypothesized to be involved in inducing both, inflammatory and anti-inflammatory/neuroprotective effects in the brain, sparking an interest in its use in ASD. Sulforaphane, a sulfur-containing phytochemical present mainly in cruciferous plants like broccoli and cabbage, has shown efficacy in activating the Nrf2 signaling pathway, which in turn brings about a protective effect on neuronal cells, especially against mitochondrial dysfunction. Its efficacy against ASD has not yet been evaluated, and in this paper, we attempt to discuss the therapeutic potential of this agent in the therapy of autism, with special emphasis on the role of the Nrf2 pathway in the disorder.

Selenium nanoparticles: Enhanced nutrition and beyond

Selenium is a trace nutrient that has both nutritional and nutraceutical functions, whereas narrow nutritional range of selenium intake limits its use. Selenium nanoparticles (SeNPs) are less toxic and more bioavailable than traditional forms of selenium, suggesting that SeNPs have the potential to replace traditional selenium in food industries and/or biomedical fields. From the perspective of how SeNPs can be applied in health area, this review comprehensively discusses SeNPs in terms of its preparation, nutritional aspect, detoxification effect of heavy metals, nutraceutical functions and anti-pathogenic microorganism effects. By physical, chemical, or biological methods, inorganic selenium can be transformed into SeNPs which have increased stability and bioavailability as well as low toxicity. SeNPs are more effective than traditional selenium form in synthesizing selenoproteins like glutathione peroxidases. SeNPs can reshape the digestive system to facilitate digestion and absorption of nutrients. SeNPs have shown excellent potential to adjunctively treat cancer patients, enhance immune system, control diabetes, and prevent rheumatoid arthritis. Additionally, SeNPs have good microbial anti-pathogenic effects and can be used with other antimicrobial agents to fight against pathogenic bacteria, fungi, or viruses. Development of novel SeNPs with enhanced functions can greatly benefit the food-, nutraceutical-, and biomedical industries.

Elucidating the molecular mechanisms underlying the induction of autophagy by antidepressant-like substances in C57BL/6J mouse testis model upon LPS challenge

The treatment of depression with pharmaceuticals is associated with many adverse side effects, including male fertility problems. The precise mechanisms by which these agents affect testicular cells remain largely unknown, but they are believed to induce cellular stress, which is sensed by the endoplasmic reticulum (ER) and the Golgi apparatus. These organelles are responsible for maintaining cellular homeostasis and regulating signal pathways that lead to autophagy or apoptosis. Therefore, in this study, we aimed to investigate the autophagy, ER, and Golgi stress-related pathways in mouse testis following treatment with antidepressant-like substances (ALS) and ALS combined with lipopolysaccharide (LPS). We found that most ALS and activated proteins are associated with the induction of apoptosis. However, when imipramine (IMI) was combined with NS-398 (a cyclooxygenase-2 inhibitor) after LPS administration, we observed a marked increase in the BECLIN1, Bcl-2, ATG16L, and LC3 expression, which are marker proteins of autophagosome formation. The expression of the BECN1 and ATG16L genes was also high compared to the control, indicating the induction of autophagy processes that may potentially protect mouse testicular cells from death and regulate metabolism in the testis. Our findings may provide a better understanding of the stress-related effects of specific ALS on the testis. Video Abstract.

Copper exerts cytotoxicity through inhibition of iron-sulfur cluster biogenesis on ISCA1/ISCA2/ISCU assembly proteins

Copper is an essential mineral nutrient that provides the cofactors for some key enzymes. However, excess copper is paradoxically cytotoxic. Wilson's disease is an autosomal recessive hereditary disease characterized by pathological copper accumulation in many organs, with high mortality and disability. Nevertheless, many questions about the molecular mechanism in Wilson's disease remain unknown and there is an imperative need to address these questions to better exploit therapeutic strategy. In this study, we constructed the mouse model of Wilson's disease, ATP7A^-/- immortalized lymphocyte cell line and ATP7B knockdown cells to explore whether copper could impair iron-sulfur cluster biogenesis in eukaryotic mitochondria. Through a series of cellular, molecular, and pharmacological analyses, we demonstrated that copper could suppress the assembly of Fe-S cluster, decrease the activity of the Fe-S enzyme and disorder the mitochondrial function both in vivo and in vitro. Mechanistically, we found that human ISCA1, ISCA2 and ISCU proteins have a strong copper-binding activity, which would hinder the process of iron-sulfur assembly. Of note, we proposed a novel mechanism of action to explain the toxicity of copper by providing evidence that iron-sulfur cluster biogenesis may be a primary target of copper toxicity both in cells and mouse models. In summary, the current work provides an in-depth study on the mechanism of copper intoxication and describes a framework for the further understanding of impaired Fe-S assembly in the pathological processes of Wilson's diseases, which helps to develop latent therapeutic strategies for the management of copper toxicity.

A NIR BODIPY-based ratiometric fluorescent probe for HClO detection with high selectivity and sensitivity in real water samples and living zebrafish

Hypochlorous acid (HClO) plays an important role in many physiological and pathological activities. In this work, a novel BODIPY-based Near-infrared (NIR) ratiometric fluorescent probe BODIPY-Hyp was designed for the rapid detection of HClO. The probe BODIPY-Hyp was highly selective and sensitive for HClO with a low detection limit of 16.74 nM and short response time of less than 60 s. The probe BODIPY-Hyp in response to HClO exhibited a significant blue-shifted fluorescence emission from 700 nm to 530 nm, and its fluorescence intensity ratio (I_{530 nm}/I_{700 nm}) increased about 1200 times before and after adding HClO. Moreover, the reaction mechanism of BODIPY-Hyp with HClO was verified by HRMS analysis, ¹H NMR titration and DFT calculations. Furthermore, BODIPY-Hyp was successfully processed into a portable test strip-based device for the detection of HClO. In addition, the probe BODIPY-Hyp could be used in real time to monitor the levels of HClO in living zebrafish larvae. In conclusion, BODIPY-Hyp has great application potential in the life and environmental sciences.

Elderberry Extracts: Characterization of the Polyphenolic Chemical Composition, Quality Consistency, Safety, Adulteration, and Attenuation of Oxidative Stress- and Inflammation-Induced Health Disorders

Elderberry is highly reputed for its health-improving effects. Multiple pieces of evidence indicate that the consumption of berries is linked to enhancing human health and preventing or delaying the onset of chronic medical conditions. Compared with other fruit, elderberry is a very rich source of anthocyanins (approximately 80% of the polyphenol content). These polyphenols are the principals that essentially contribute to the high antioxidant and anti-inflammatory capacities and the health benefits of elderberry fruit extract. These health effects include attenuation of cardiovascular, neurodegenerative, and inflammatory disorders, as well as anti-diabetic, anticancer, antiviral, and immuno-stimulatory effects. Sales of elderberry supplements skyrocketed to $320 million over the year 2020, according to an American Botanical Council (ABC) report, which is attributable to the purported immune-enhancing effects of elderberry. In the current review, the chemical composition of the polyphenolic content of the European elderberry (Sambucus nigra) and the American elderberry (Sambucus canadensis), as well as the analytical techniques employed to analyze, characterize, and ascertain the chemical consistency will be addressed. Further, the factors that influence the consistency of the polyphenolic chemical composition, and hence, the consistency of the health benefits of elderberry extracts will be presented. Additionally, adulteration and safety as factors contributing to consistency will be covered. The role of elderberry in enhancing human health alone with the pharmacological basis, the cellular pathways, and the molecular mechanisms underlying the observed health benefits of elderberry fruit extracts will be also reviewed.

Lung injury and oxidative stress induced by inhaled chlorine in mice is associated with proinflammatory activation of macrophages and altered bioenergetics

Chlorine (Cl2) gas is a highly toxic and oxidizing irritant that causes life-threatening lung injuries. Herein, we investigated the impact of Cl2-induced injury and oxidative stress on lung macrophage phenotype and function. Spontaneously breathing male C57BL/6J mice were exposed to air or Cl2 (300 ppm, 25 min) in a whole-body exposure chamber. Bronchoalveolar lavage (BAL) fluid and cells, and lung tissue were collected 24 h later and analyzed for markers of injury, oxidative stress and macrophage activation. Exposure of mice to Cl2 resulted in increases in numbers of BAL cells and levels of IgM, total protein, and fibrinogen, indicating alveolar epithelial barrier dysfunction and inflammation. BAL levels of inflammatory proteins including surfactant protein (SP)-D, soluble receptor for glycation end product (sRAGE) and matrix metalloproteinase (MMP)-9 were also increased. Cl2 inhalation resulted in upregulation of phospho-histone H2A.X, a marker of double-strand DNA breaks in the bronchiolar epithelium and alveolar cells; oxidative stress proteins, heme oxygenase (HO)-1 and catalase were also upregulated. Flow cytometric analysis of BAL cells revealed increases in proinflammatory macrophages following Cl2 exposure, whereas numbers of resident and antiinflammatory macrophages were not altered. This was associated with increases in numbers of macrophages expressing cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS), markers of proinflammatory activation, with no effect on mannose receptor (MR) or Ym-1 expression, markers of antiinflammatory activation. Metabolic analysis of lung cells showed increases in glycolytic activity following Cl2 exposure in line with proinflammatory macrophage activation. Mechanistic understanding of Cl2-induced injury will be useful in the identification of efficacious countermeasures for mitigating morbidity and mortality of this highly toxic gas.

Urinary concentrations of fungicide carbendazim's metabolite and associations with oxidative stress biomarkers in young children

Carbendazim (CBDZ) is the most widely used fungicide in China. It is ubiquitous in environment and can induce oxidative stress in mammals, while data on occurrence of its metabolite in human urine are scarce, and the relationship between CBDZ and oxidative stress biomarkers (OSBs) in young children has not been examined. The aim of this study was to measure the concentrations of methyl 5-hydroxy-2-benzimidazolecarbamate (5-HBC, the main metabolite of CBDZ in urine) in 390 urine samples collected from 130 healthy young (< 6.6 years old) children from Shenzhen and Wuhan, in south and central China, respectively, and to evaluate the associations of 5-HBC with three selected OSBs (4-HNEMA, 8-OHG, and 8-OHdG, for lipid, RNA, and DNA, respectively). 5-HBC was found in 99.2% of the urine samples at concentrations ranging from below the method detection limit (< 0.005 ng/mL) to 10.9 ng/mL (median: 0.11 ng/mL). Moderate inter-day reproducibility was found for specific gravity-adjusted 5-HBC concentrations (intraclass correlation coefficient: 0.50). The urinary 5-HBC concentrations were significantly and positively associated with 4-HNEMA (p < 0.01). An interquartile range increase in urinary 5-HBC concentrations was associated with a 42.1% increase in 4-HNEMA, which implied that CBDZ exposure might be associated with lipid peroxidation in young children without occupational exposure. As far as we know, this pilot study is the first to report urinary 5-HBC and its associations with OSBs in children.

Fluorescent phenothiazine-fused boron complexes for ratiometric hypochlorite imaging

Fluorescent hypochlorite probes with ratiometric imaging ability are highly desirable for imaging hypochlorite in biological systems. However, it is still challenging to develop new scaffolds for these probes. In this study, we demonstrate that phenothiazine-fused boron complexes are promising scaffolds for the design of ratiometric fluorescent hypochlorite probes. The synthesized complexes based on the scaffold show ultrafast and ratiometric absorption/fluorescence changes for hypochlorite. We also developed an endoplasmic reticulum-targeting probe and demonstrated that it has excellent real-time imaging ability for both endogenous and exogenous hypochlorite in the endoplasmic reticulum of living cells.

BODIPY-Based Fluorescent Probes for Selective Visualization of Endogenous Hypochlorous Acid in Living Cells via Triazolopyridine Formation

In this work, the two pyridylhydrazone-tethered BODIPY compounds (2 and 3) were synthesized. These compounds aimed to detect hypochlorous acid (HOCl) species via cyclic triazolopyridine formation. The open forms and the resulting cyclic forms of BODIPYs (2, 3, 4, and 5) were fully characterized by nuclear magnetic resonance, mass spectrometry, infrared spectroscopy, and single-crystal X-ray diffraction. These two probes can selectively detect HOCl through a fluorescence turn-on mechanism with the limit of detections of 0.21 µM and 0.77 µM for compounds 2 and 3, respectively. This fluorescence enhancement phenomenon could be the effect from C = N isomerization inhibition due to HOCl-triggered triazolopyridine formation. In cell imaging experiments, these compounds showed excellent biocompatibility toward RAW 264.7 murine live macrophage cells and greatly visualized endogenous HOCl in living cells stimulated with lipopolysaccharide.

The therapeutic effects of coenzyme Q10 on surgically induced endometriosis in Sprague Dawley rats

The aim of this study was to evaluate the effects of coenzyme Q10 in the treatment of endometriosis rat models. Twenty seven Sprague Dawley rats were divided into four groups; Control Group (n = 7; Endometriosis group), Reference Group (n = 6; Endometriosis + Buserelin acetate, 20 mg/kg), CoQ10 Group-I (n = 7; Endometriosis + CoQ10, 50 mg/kg) and CoQ10 Group-II (n = 7; Endometriosis + CoQ10, 100 mg/kg). At the end of the experiment, all the rats were sacrificed, and the volume and histoarchitecture of endometrial implants were evaluated. The mast cells were determined by Toluidine blue and collagen fiber density was analysed by Masson's Trichrome staining. Tumour necrosis factor and vascular endothelial growth factor (VEGF) levels were analysed by enzyme-linked immunosorbent assay in peritoneal fluid and VEGF and matrix metalloproteinase-9 (MMP-9) were evaluated by immunohistochemistry. Terminal deoxynucleotidil transferase-mediated dUTP Nick end labelling (TUNEL) was also used for the detection of apoptotic cells. The CoQ10 treatment significantly decreased the volume of endometriotic implants, VEGF, and MMP-9 immunoreactivity and increased TUNEL-positive cells. The findings of the study suggest that CoQ10 can be used in endometriosis treatment by suppressing the endometriotic implants.IMPACT STATEMENTWhat is already known on this subject? Endometriosis is a gynaecological disorder and previous studies have shown that different treatments with antioxidants cause significant regression in the endometriotic implants.What the results of this study add? In this study, CoQ10 reduced intra-abdominal adhesion scores and volume of the endometriotic implants. In addition, CoQ10 treatment affected mast cell, TNF-α, VEGF, and MMP-9.What of these findings for clinical practice and/or further research? CoQ10 treatments may be possible to apply, it can contribute to science in terms of a new therapeutic treatment for endometriosis. Further studies are required to evaluate the Coenzyme Q10's effects on pain and subfertility in endometriosis.

Developmental neurotoxicity of silver nanoparticles: the current state of knowledge and future directions

The increasing production and use of silver nanoparticles (AgNPs) as an antimicrobial agent in an array of medical and commercial products, including those designed for infants and children, poses a substantial risk of exposure during the developmental period. This review summarizes current knowledge on developmental neurotoxicity of AgNPs in both pre- and post-natal stages with a focus on the biological specificity of immature organisms that predisposes them to neurotoxic insults as well as the molecular mechanisms underlying AgNP-induced neurotoxicity. The current review revealed that AgNPs increase the permeability of the blood-brain barrier (BBB) and selectively damage neurons in the brain of immature rats exposed pre and postnatally. Among the AgNP-induced molecular mechanisms underlying toxic insult is cellular stress, which can consequently lead to cell death. Glutamatergic neurons and NMDAR-mediated neurotransmission also appear to be a target for AgNPs during the postnatal period of exposure. Collected data indicate also that our current knowledge of the impact of AgNPs on the developing nervous system remains insufficient and further studies are required during different stages of development with investigation of environmentally-relevant doses of exposure.

Protective effect of grape seed extract against chronic physical stress-induced zona fasciculata injury in male rats: Functional, immunohistochemical and electron microscopic study

In the present study, we investigated the antioxidant effect of grape seed extract (GSE) against chronic immobilization stress-induced zona fasciculata injury in Wistar male rats. Thirty male rats were divided into three groups: Non-stress group: rats were not subjected to stress protocol and received distilled water orally for 30 days. Stress group: rats received distilled water orally for 15 consecutive days before the induction of chronic immobilization stress experiment (repeated stress for 15 consecutive days), distilled water was continued along with the constant stress experiment. GSE-stress group: rats treated with oral GSE (300 mg/kg), administered orally for 15 consecutive days before the induction of chronic immobilization stress experiment (repeated stress for 15 consecutive days), GSE was continued along with the stress exposure. Chronic stress was induced by placing each animal in a restrainer for 2 h daily for 15 consecutive days in both Stress and GSE-stress groups. The serum corticosterone and adrenal cortex malondialdehyde (MDA) levels were measured as indices of stress. Immunohistochemistry of the inducible nitric oxide synthase (iNOS) as a nitrosative stress marker beside the adrenal cortex's ultrastructure, particularly zona fasciculata, was assessed. Chronic restraint stress significantly elevated the serum corticosterone and adrenal cortex MDA levels, while oral administration of GSE reduced the serum corticosterone level, adrenal cortex MDA levels, and iNOS immunoreactivity in zona fasciculata. Besides, adrenocortical ultrastructure significantly improved. These results suggested that GSE enhanced the antioxidant defense against reactive oxygen species produced under chronic stress conditions, protecting the adrenal cortex.

Antiproliferation- and Apoptosis-Inducible Effects of a Novel Nitrated [6,6,6]Tricycle Derivative (SK2) on Oral Cancer Cells

The benzo-fused dioxabicyclo[3.3.1]nonane core is the central framework in several natural products. Using this core, we had developed a novel nitrated [6,6,6]tricycle-derived compound containing an n-butyloxy group, namely, SK2. The anticancer potential of SK2 was not assessed. This study aimed to determine the antiproliferative function and investigated possible mechanisms of SK2 acting on oral cancer cells. SK2 preferentially killed oral cancer cells but caused no harmful effect on non-malignant oral cells. After the SK2 exposure of oral cancer cells, cells in the sub-G1 phase accumulated. This apoptosis-like outcome of SK2 treatment was validated to be apoptosis via observing an increasing annexin V population. Mechanistically, apoptosis signalers such as pancaspase, caspases 8, caspase 9, and caspase 3 were activated by SK2 in oral cancer cells. SK2 induced oxidative-stress-associated changes. Furthermore, SK2 caused DNA damage (γH2AX and 8-hydroxy-2'-deoxyguanosine). In conclusion, a novel nitrated [6,6,6]tricycle-derived compound, SK2, exhibits a preferential antiproliferative effect on oral cancer cells, accompanied by apoptosis, oxidative stress, and DNA damage.

A spectroscopic probe for hypochlorous acid detection

A spectroscopic probe CMBT was synthesized and characterized. CMBT showed the specific recognition for HClO based on the turn-on blue fluorescence and naked-eye change from pink to colorless. NMR, IR, HRMS-ESI, and spectral analysis suggested that colorimetric and fluorescent change of CMBT to HClO originated from the conversion of CMBT to starting material coumarin-aldehyde 1 caused by the oxidization of HClO, which was responsible for the fluorescence recovery. The detection limit was calculated to be 1.61 μM and 6.58 μM for fluorescence and UV-vis analysis with a range up to 1 mM. HClO's fluorescence detection was successfully achieved in tap and river water samples. The prepared convenient paper test strips showed a distinct color change in varying concentrations of HClO. A multi-input molecular logic circuit was constructed.

Analysis of 19 urinary biomarkers of oxidative stress, nitrative stress, metabolic disorders, and inflammation using liquid chromatography–tandem mass spectrometry

Environmental chemical exposures have been associated with cancer, diabetes, hormonal and immunological disorders, and cardiovascular diseases. Some direct effects of chemical exposure that are precursors to adverse health outcomes, including oxidative stress, nitrative stress, hormonal imbalance, neutrophilia, and eosinophilia, can be assessed through the analysis of biomarkers in urine. In this study, we describe a novel methodology for the determination of 19 biomarkers of health effects: malondialdehyde (MDA), 8-isoprostaglandin-F_2α (8-PGF_2α), 11-β-prostaglandin-F_2α (11-PGF_2α), 15-prostaglandin-F_2α (15-PGF_2α), 8-iso-15-prostaglandin-F_2α (8,15-PGF_2α), 8-hydroxy-2′-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-HdG), 8-hydroxyguanine (8-HG), dityrosine (diY), allantoin (Alla), and two metabolic products of 4-hydroxynonenal (HNE), namely 4-hydroxy-2-nonenal glutathione (HNE-GSH) and 4-hydroxy-2-nonenal mercapturic acid (HNE-MA) (in total, 12 oxidative stress biomarkers, OSBs); 8-nitroguanosine (8-NdG), 8-nitroguanine (8-NG), and 3-nitrotyrosine (NY) (3 nitrative stress biomarkers, NSBs); chlorotyrosine (CY) and bromotyrosine (BY) (2 inflammatory biomarkers); and the advanced glycation end-products (AGEs) N^ε-carboxymethyllysine (CML) and N^ε-carboxyethyllysine (CEL) (2 metabolic disorder biomarkers). Since these biomarkers are trigged by a variety of environmental insults and produced by different biomolecular pathways, their selective and sensitive determination in urine would help broadly elucidate the pathogenesis of diseases mediated by environmental factors.

Attributes of oxidative stress in the reproductive toxicity of nickel oxide nanoparticles in male rats

The nanoparticles of nickel are now being widely used in industrial, commercial, and biomedical applications. In recent years, health safety issues posed by them have aroused concerns among health scientists. The aim of the present study was to investigate the role of oxidative stress in male reproductive toxicity induced by nickel oxide nanoparticles in rats. Male Wistar rats (140-170 g) were administered with nickel oxide nanoparticles (NiONPs) (particles size <30 nm) (5 mg/kg body weight) by gavage for 30 days. Its effects on different parameters, viz., sperm count, motility, and morphology, were investigated. DNA damage in sperms was monitored through comet assay. All these observations indicated a spermicidal effect of NiONPs. Results on lipid peroxidation (MDA, H₂O₂, and NO) and oxidative stress (GSH, GPx, and catalase) thus studied in testes exhibited adverse effects of NiONPs. Histopathological results on male reproductive organs, viz., testis, epididymis, vas deferens, seminal vesicles, and prostate also demonstrated moderate to severe toxicity. A comparison of these results with those obtained on nickel oxide microparticle (NiOMP)-treated rats showed that NiONPs are more toxic than NiOMPs. Furthermore, NiONPs could create an imbalance between oxidants and antioxidants in the testes. It is concluded that redox imbalance in testes constitutes a major mechanism of NiONP-induced reproductive toxicity.

Transcriptional reprogramming by oxidative stress occurs within a predefined chromatin accessibility landscape

Reactive oxygen species (ROS) are important signaling molecules in many physiological processes, yet excess ROS leads to cell damage and can lead to pathology. Accordingly, cells need to maintain tight regulation of ROS levels, and ROS-responsive transcriptional reprogramming is central to this process. Although it has long been recognized that oxidative stress leads to rapid, significant changes in gene expression, the impact of oxidative stress on the underlying chromatin accessibility landscape remained unclear. Here, we asked whether ROS-responsive transcriptional reprogramming is accompanied by reprogramming of the chromatin environment in MCF7 human breast cancer cells. Using a time-course exposure to multiple inducers of oxidative stress, we determined that the widespread ROS-responsive changes in gene expression induced by ROS occur with minimal changes to the chromatin environment. While we did observe changes in chromatin accessibility, these changes were: (1) far less numerous than gene expression changes after oxidative stress, and (2) occur within pre-existing regions of accessible chromatin. Transcription factor (TF) footprinting analysis of our ATAC-seq experiments identified 5 TFs or TF families with evidence for ROS-responsive changes in DNA binding: NRF2, AP-1, p53, NFY, and SP/KLF. Importantly, several of these (AP-1, NF-Y, and SP/KLF factors) have not been previously implicated as widespread regulators in the response to ROS. In summary, we have characterized genome-wide changes in gene expression and chromatin accessibility in response to ROS treatment of MCF7 cells, and we have found that regulation of the large-scale transcriptional response to excess ROS is primarily constrained by the cell's pre-existing chromatin landscape.

Air Pollution and the Airways: Lessons from a Century of Human Urbanization

Since the industrial revolution, air pollution has become a major problem causing several health problems involving the airways as well as the cardiovascular, reproductive, or neurological system. According to the WHO, about 3.6 million deaths every year are related to inhalation of polluted air, specifically due to pulmonary diseases. Polluted air first encounters the airways, which are a major human defense mechanism to reduce the risk of this aggressor. Air pollution consists of a mixture of potentially harmful compounds such as particulate matter, ozone, carbon monoxide, volatile organic compounds, and heavy metals, each having its own effects on the human body. In the last decades, a lot of research investigating the underlying risks and effects of air pollution and/or its specific compounds on the airways, has been performed, involving both in vivo and in vitro experiments. The goal of this review is to give an overview of the recent data on the effects of air pollution on healthy and diseased airways or models of airway disease, such as asthma or chronic obstructive pulmonary disease. Therefore, we focused on studies involving pollution and airway symptoms and/or damage both in mice and humans.

Curcumin Decreases Hippocampal Neurodegeneration and Nitro-Oxidative Damage to Plasma Proteins and Lipids Caused by Short-Term Exposure to Ozone

Neurodegeneration is the consequence of harmful events affecting the nervous system that lead to neuronal death. Toxic substances, including air pollutants, are capable of inducing neurodegeneration. Ozone (O₃) is the most oxidative toxic pollutant. O₃ reacts with cellular components and forms reactive oxygen and nitrogen species, triggering nitro-oxidative damage during short-term exposure. Curcumin (CUR) is a natural phenolic molecule bearing well-documented antioxidant and anti-inflammatory biological activities in diverse experimental models. The aim of this work was to evaluate the effect of preventive dietary administration of CUR against hippocampal neurodegeneration and nitro-oxidative damage caused by short-term exposure to O₃. Eighty Wistar male rats were distributed into four experimental groups, twenty rats each: intact control; CUR dietary supplementation without O₃ exposure; exposure to 0.7 ppm of O₃; and exposed to O₃ with CUR dietary supplementation. Five rats from each group were sacrificed at 1, 2, 4, and 8 h of exposure. The CUR dose was 5.6 mg/kg and adjusted according to food consumption. CUR significantly decreased oxidative damage to plasma lipids and proteins, as well as neurodegeneration in CA1 and CA3 hippocampal regions. Concluding, CUR proved effective protection in decreasing neurodegeneration in the hippocampus and prevented systemic oxidative damage.

Selective Imaging of HClO in the Liver Tissue In Vivo Using a Near-infrared Hepatocyte-specific Fluorescent Probe

Liver injury is typified by an inflammatory response. Hypochlorous acid (HClO), an important endogenous reactive oxygen species, is regarded as a biomarker associated with liver injury. Near-infrared (NIR) fluorescent probes with the advantage of deep tissue penetrating and low auto-fluorescence interference are more suitable for bioimaging in vivo. Thus, in this work, we designed and synthesized a novel NIR hepatocyte-specific fluorescent probe named NHF. The probe NHF showed fast response (<3 s), large spectral variation, and good selectivity to trace HClO in buffer solution. By employing N-acetylgalactosamine (GalNAc) as the targeting ligand, probe NHF can be actively delivered to the liver tissue of zebrafish and mice. It is important that probe NHF is the first NIR hepatocyte-specific fluorescent probe, which successfully visualized the up-regulation of endogenous HClO in the oxygen-glucose deprivation/reperfusion (OGD/R) model HepG2 cells and dynamically monitored APAP-induced endogenous HClO in the liver tissue of zebrafish and mice.

Superoxide Dismutase Administration: A Review of Proposed Human Uses

Superoxide dismutases (SODs) are metalloenzymes that play a major role in antioxidant defense against oxidative stress in the body. SOD supplementation may therefore trigger the endogenous antioxidant machinery for the neutralization of free-radical excess and be used in a variety of pathological settings. This paper aimed to provide an extensive review of the possible uses of SODs in a range of pathological settings, as well as describe the current pitfalls and the delivery strategies that are in development to solve bioavailability issues. We carried out a PubMed query, using the keywords "SOD", "SOD mimetics", "SOD supplementation", which included papers published in the English language, between 2012 and 2020, on the potential therapeutic applications of SODs, including detoxification strategies. As highlighted in this paper, it can be argued that the generic antioxidant effects of SODs are beneficial under all tested conditions, from ocular and cardiovascular diseases to neurodegenerative disorders and metabolic diseases, including diabetes and its complications and obesity. However, it must be underlined that clinical evidence for its efficacy is limited and consequently, this efficacy is currently far from being demonstrated.

Comparative Antioxidant Analysis of Moringa oleifera Leaf Extracts from South Western States in Nigeria

Background

Moringa oleifera is a medicinal plant that ethnobotanical studies have shown its inclusion in treatment of many ailments such as diarrhea, diabetes, epilepsy, wound healing and arthritis. It is a plant that was believed to originate from India but could now be found in both the tropics and the sub-topics. Earlier reports have not addressed the association between the location of plant collection and its antioxidant contents. In this study, Moringa oleifera leaves were collected from 21 locations within the south western states of Nigeria. Leaves from each of the locations were dried and evaluated for total phenols, tannin, saponin and flavonoid. DPPH scavenging activity, nitric oxide scavenging activity and inhibition of lipid peroxidation were also evaluated.

Results

All the parameters analysed showed significant within- and between-group differences. Some locations had greater DPPH scavenging ability than the standard (quercetin).

Conclusion

Environmental parameters like annual precipitation, minimum temperature and maximum temperature, and soil type of the location of the plants showed influence on the level of antioxidant, while further analysis using metaboanalyst showed a notable effect of soil type on the antioxidant activity.

Predictors of liver fat among children and adolescents from five different ethnic groups

OBJECTIVES

As rates of obesity around the world have increased, so has the detection of high level of liver fat in children and adolescents. This may put them at risk for cardiovascular disease later in life. This analysis of a cross-sectional population-based study of children and adolescents evaluated demographic and lifestyle determinants of percent liver fat.

METHODS

Healthy participants (123 girls and 99 boys aged 5-17 years) recruited by convenience sampling in three locations completed questionnaires, anthropometric measurements, and dual X-ray absorptiometry and magnetic resonance imaging (MRI) assessment. General linear models were applied to estimate the association of demographic, anthropometric, and dietary factors as well as physical activity with MRI-based percent liver fat.

RESULTS

The strongest predictor of liver fat was body mass index (BMI; p < 0.0001); overweight and obesity were associated with 0.5% and 1% higher liver fat levels. The respective adjusted mean percent values were 2.9 (95% CI 2.7, 3.1) and 3.4 (95% CI 3.2, 3.6) as compared to normal weight (2.4; 95% CI 2.3, 2.6). Mean percent liver fat was highest in Whites and African Americans, intermediate in Hispanic, and lowest among Asians and Native Hawaiians/Pacific Islanders (p < 0.0001). Age (p = 0.67), sex (p = 0.28), physical activity (p = 0.74), and diet quality (p = 0.70) were not significantly related with liver fat.

CONCLUSIONS

This study in multiethnic children and adolescents confirms the strong relationship of BMI with percent liver fat even in a population with low liver fat levels without detecting an association with age, sex, and dietary or physical activity patterns.

Antioxidants protect against gingival overgrowth induced by cyclosporine A

OBJECTIVE

We investigated the importance of reactive oxygen species (ROS) on developing gingival overgrowth (GO) and then introduced the antioxidant strategy to prevent, or even reduce GO.

BACKGROUND

Gingival overgrowth is a common side effect of the patients receiving cyclosporine A (CsA), an immune suppressant. Although it has been broadly investigated, the exact pathogenesis of the induced GO is still uncertain.

METHODS

We cultured human primary gingival fibroblasts and used animal model of GO to investigate the ameliorative effects of antioxidants on CsA-induced GO. To examine the CsA-induced oxidative stress, associated genes and protein expression, and the overgrown gingiva of rats by using immunocytochemistry, confocal laser scanning microscopy, real-time PCR, ELISA, gelatin zymography, gingival morphological, and immunohistochemical analysis.

RESULTS

We found for the first time that ROS was responsible for the CsA-induced oxidative stress and TGF-β1 expression in human primary gingival fibroblasts, as well as the GO of rats. The antioxidants (oxidative scavenger of vitamin E and an antioxidative enzyme inducer of hemin) ameliorated CsA-induced pathological and morphological alterations of GO without affected the CsA-suppressed il-2 expression in rats. CsA-induced oxidative stress, HO-1, TGF-β1, and type II EMT were also rescued by antioxidants treatment.

CONCLUSIONS

We concluded that CsA repetitively stimulating the production of ROS is the cause of CsA-GO which is ameliorated by treating antioxidants, including vitamin E and sulforaphane. Furthermore, the immunosuppressive effect of CsA is not interfered by antioxidant treatments in rats. This finding may thus help the clinician devise better prevention strategies in patients susceptible to GO.

HDAC6 Mediates Macrophage iNOS Expression and Excessive Nitric Oxide Production in the Blood During Endotoxemia

Excessive nitric oxide (NO) production and NO-mediated nitrative stress contribute to vascular dysfunction, inflammation, and tissue injury in septic shock. New therapeutic targets are urgently needed to provide better control of NO level during septic shock. In the present study, we investigated the role of HDAC6 in the regulation of NO production and nitrative stress in a mouse model of endotoxin-induced septic shock. HDAC6 deficient mice and a specific HDAC6 inhibitor were utilized in our studies. Our data clearly indicate that HDAC6 is an important mediator of NO production in macrophages. HDAC6 mediates NO production through the regulation of iNOS expression in macrophages. HDAC6 up-regulates iNOS expression in macrophages by modulating STAT1 activation and IRF-1 expression. HDAC6 inhibition potently blocked endotoxin-induced STAT1 activation and iNOS expression in macrophages. Furthermore, HDAC6 contributes to excessive NO production and nitrotyrosine level in the blood and promotes iNOS expression in the lung tissues during septic shock. Our data reveal a novel HDAC6/STAT1/iNOS pathway that mediates excessive NO production and nitrative stress in septic shock.

Metal body burden and tissue oxidative status in the bivalve Venerupis decussata from Tunisian coastal lagoons

Coastal transitional waters are exposed to many anthropogenic threats. This study aims to assess the trace metals' pollution status of transitional waters by evaluating its biological effects in the clam Venerupis decussata. Among the studied sites along the Tunisian littoral, South Tunis and Boughrara were the most impacted, since clams from these two lagoons presented significant differences in: (i) trace metal contents, (ii) in-cell hydrogen peroxide, (iii) enzymatic and non-enzymatic defenses, (iv) damage to lipids and proteins, and (v) protein post-translational modifications. These changes related to evident histopathological traits. PCA showed a clear separation between the digestive gland and gills tissues and illustrated an impact gradient in Tunisian coastal lagoons. Water temperature was revealed as an added natural stressor that, when concurring with high pollution, may jeopardize an ecosystem's health and contribute to the accumulation of hazardous metals in organisms.

A new red fluorescent probe based on rosamine–phenothiazine for the highly selective and rapid detection of hypochlorite and its bioimaging in live cells

A new red fluorescent probe based on rosamine–phenothiazine for highly selective and rapid detection of hypochlorite and its bioimaging in live cells.

BODIPY-based selenides as fluorescent probes for rapid, sensitive and mitochondria-specific detection of hypochlorous acid

Hypochlorous acid (HClO) is a powerful microbicidal agent in the innate immue system; however, abnormal HClO levels can cause tissue damage and many diseases. Thus, it is vitally important to develop facile, rapid and accurate analytical methods for the detection of HClO/ClO^-in vitro and in vivo. In this work, we have constructed three meso-substituted BODIPY selenides with different hydrocarbyl groups (ethyl for BSe-Et, benzyl for BSe-Bz and phenyl for BSe-Ph) as fluorescent probes for the detection of HClO/ClO^-. All three non-fluorescent probes can sense HClO/ClO^- to form fluorescent selenoxides by blocking the photo-induced electron transfer process. Their sensing properties display a clear relationship with the structure of the hydrocarbyl. The sensing reactivity is heavily dependent on the electron-donating ability of hydrocarbyls, with the order of the response time as BSe-Et (2 s) < BSe-Bz (5 s) ≪ BSe-Ph (>100 s). Both BSe-Et and BSe-Bz afford a large fluorescence response and very low detection limits (0.3 nM and 0.8 nM), and BSe-Bz displays a higher selectivity over BSe-Et. Finally, as a representative, BSe-Bz was successfully applied to the detection of exo- and endogenous HClO in living cells, and demonstrated to be a mitochondria-localized fluorescent probe.

Design Principles, Sensing Mechanisms, and Applications of Highly Specific Fluorescent Probes for HOCl/OCl

Hypochlorous acid/hypochlorite (HOCl/OCl^-), one of the most important reactive oxygen species (ROS), plays vital roles in various physiological and pathological processes. At normal concentrations, OCl^- acts as part of an immune defense system by destroying invasive bacteria and pathogens. However, nonproperly located or excessive amounts of OCl^- are related to many diseases, including cancers. Thus, detection of OCl^- has great importance. Owing to their high sensitivities, selectivities, fast response times, technical simplicities, and high temporal and spatial resolution, fluorescent probes are powerful tools for in vitro and in vivo sensing of target substances. This Account focuses on the development of new chemosensors for detection of OCl^-, which operate by undergoing a chemical reaction with this ROS in conjunction with a change in emission properties. As part of the presentation, we first introduce several important factors that need to be considered in the design of fluorescent chemosensors for OCl^-, including fluorophores, reaction groups, cosolvents, and buffers. Discussion here revolves around the need to select fluorophores that resist oxidation by OCl^-. As well, attention is given to the sensitivities and selectivities of groups in the sensors that react with OCl^- to trigger a fluorescence response. Moreover, well-known reaction groups, which react with highly reactive ROS (hROS), have been redesigned to be specific for OCl^-. In addition, it is pointed out that several cosolvents and buffers such as DMSO and HEPES are not suitable for use in systems for the detection of OCl^- because they are readily oxidized by this ROS. We further discuss recent investigations carried out by us and others aimed at the development of fluorescent probes for in vitro and in vivo detection of OCl^-. These efforts led to the new "dual lock" strategy for designing OCl^- chemosensors as well as several new specific reaction groups such as imidazoline-2-thiones and imidazoline-2-boranes. Probes created using this strategy and the new reacting groups have been successfully applied to imaging exogenous and endogenous OCl^- in live cells and/or tissues. The design concepts and strategies emanating from our studies of fluorescent OCl^- probes have provided insight into the general field of fluorescent probes. Despite the progress made thus far, challenges still remain in developing and applying fluorescent OCl^- probes. For example, more highly specific and sensitive fluorescent OCl^- probes are still in great demand for studies of the biological roles played by OCl^-. Thus, interdisciplinary collaborations of chemists, biologists, and medical practitioners are needed to drive future developments of OCl^- probes for disease diagnosis and drug screening.

Therapeutic effects of resveratrol in Escherichia coli-induced rat endometritis model

Endometritis is an inflammatory disorder of the endometrial lining of the uterine tissue in postpartum stage. Endometritis mostly progresses subclinically and causes infertility through the disruption of the hormonal balance. It has been shown in many studies that resveratrol has anti-inflammatory and antioxidant properties. However, the possible beneficial effects of resveratrol in endometritis have not been determined yet. The aim of the present study is to evaluate the treatment potential of resveratrol in an experimentally induced endometritis model in rats. Endometritis was induced in 12-week-old female, nonpregnant, Sprague Dawley rats. The animals were divided into six groups: control (NaCl 0.9%) and endometritis (NaCl 0.9%), marbofloxacin + PGF_2α, marbofloxacin, marbofloxacin + resveratrol, and resveratrol groups. To induce endometritis, 5 mg/kg/s.c. progesterone was given for 5 days, and then Escherichia coli (50 μl, 1 × 10⁵ cfu/rat) was injected in the right cornu uteri following laparotomy. Sixteen hours after bacterial inoculation, the treatment protocol was applied for 14 days. At the end of the experiment, the total oxidant status (TOS) and total antioxidant status (TAS) were examined spectrophotometrically in uterus tissues. The severity of inflammation in uterus samples and follicular activity in ovarian tissues were histopathologically evaluated. In addition, serum cytokine levels were determined. While TAS in uterine tissue significantly increased in the resveratrol group when compared to that of the other groups (p < 0.05), there was no difference between the groups in TOS (p > 0.05). The inflammation of the endometrium and the numbers of corpus luteum in the endometritis group were highly significant when compared to those of the other groups (p < 0.05). The recovery of inflammation and follicular activity were similar to those of the other groups in resveratrol group. However, it was realized that resveratrol administration reduced serum cytokine levels. According to the results of the current study, resveratrol was found to be effective in the treatment of endometritis with its antioxidant and anti-inflammatory functions.

A highly specific fluorescent probe for rapid detection of hypochlorous acidin vivoand in water samples

We report the development of a new chromogenic and fluorogenic probe for the detection of HOCl in zebrafish, mice with arthritis and environmental water samples.

Extending Hypochlorite Sensing from Cells to Elesclomol-Treated Tumors in Vivo by Using a Near-Infrared Dual-Phosphorescent Nanoprobe

Reactive oxygen species (ROS), when beyond the threshold, can exhaust the capacity of cellular antioxidants and ultimately trigger cell apoptosis in tumor biology. However, the roles of hypochlorite (ClO^-) in this process are much less clear compared with those of ROS, and its detection is easily obstructed by tissue penetration and endogenous fluorophores. Herein, we first synthesized a near-infrared (NIR) ratiometric ClO^- probe (Ir NP) composed of two kinds of phosphorescent iridium(III) complexes (Ir1 and Ir2) encapsulated with amphiphilic DSPE-mPEG5000. Ir NPs are dual-emissive and show obvious changes in phosphorescence intensity ratios and lifetimes of two emission bands upon exposure to ClO^-. During the ClO^- detection, ratiometric photoluminescence imaging is much more reliable over the intensity-based one for its self-calibration, while time-resolved photoluminescence imaging (TRPI) could distinguish the phosphorescence with long lifetime of Ir NPs from short-lived autofluorescence of tissues, resulting in the high accuracy of ClO^- determination. With NIR emission, a long phosphorescence lifetime, fast response, and excellent biocompatibility, Ir NPs were applied to the detection of ClO^- in vitro and in vivo by means of ratiometric phosphorescence imaging and TRPI with high signal-to noise-ratios (SNR). Importantly, we demonstrated the elevated ClO^- in elesclomol-stimulated tumors in living mice for the first time, which holds great potential for the visualization of the boost of ClO^- in anti-carcinogen-treated tumors and the further investigation of ROS-related oncotherapeutics.

Fisetin Attenuates Metabolic Dysfunction in Mice Challenged with a High-Fructose Diet

Excess fructose consumption can lead to metabolic syndrome, including insulin resistance, dyslipidemia, and hepatic injury, which are associated with oxidative stress and inflammation. The present study was to investigate whether fisetin improved multiple disturbances induced by fructose consumption. First, fisetin was found to be nontoxic to mice after an 8 week treatment. Second, the mice fed with a high-fructose (HFru)-diet for 8 weeks exhibited insulin resistance, dyslipidemia, hepatic injury, oxidative stress, and inflammation. Fisetin supplementation effectively improved the undesirable results mentioned above when compared to the HFru group. Meanwhile, fisetin significantly suppressed the nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) pathway and activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in mice fed with HFru. Our findings demonstrated that fisetin exerted the beneficial effects in HFru-feeding mice, which might be associated with suppression of NF-κB and activation of the Nrf2 pathway.

Relaxation dynamics of saturated and unsaturated oriented lipid bilayers

We present experimental measurements and analysis of the dynamics and the phase behaviour of saturated DMPC and unsaturated DOPC oriented multi-lamellar bilayers. Elastic and inelastic neutron scattering were used to directly probe the dynamical processes of these membrane systems on time and length scales relevant to the internal and localized motion of lipid monomers. Mobility in this regime can be informative in elucidating the local interactions responsible for material properties of these fluid lipid systems. DMPC and DOPC are structurally similar in terms of their membrane hydrophobic thickness; however, they exhibit different mechanical properties in terms of both elastic compressibility and bending moduli. The analyses suggest that the constraint imposed by the double bonds in DOPC acyl chains restricts atomic motion in both liquid and gel phases compared to DMPC. We discuss applications of molecular dynamics to further elucidate the atomic details of the dynamical processes. Such an understanding may suggest how membrane properties can be tuned using a variety of different lipid species.

Impact of ozone on claudins and tight junctions in the lungs

Claudins (CLDNs) are a major transmembrane protein component of tight junctions (TJs) in endothelia and epithelia. CLDNs are not only essential for sustaining the role of TJs in cell permeability but are also vital for cell signaling through protein-protein interactions. Ozone induces oxidative stress and lung inflammation in humans and experimental models, but the impact of ozone on claudins remains poorly understood. This study was to determine the expression of TJ proteins, such as claudin 3, 4, 5, and 14 following ozone exposure. Mice were exposed to 0.1, 1, or 2 ppm of ozone or ambient air for 6 h for 3 days. The impact of ozone on CLDNs, Nrf2, Keap1, and reactive oxygen species (ROS) were estimated using immunoblotting, immunohistochemical staining, confocal imaging, and ELISA analysis in mice and bronchial epithelial cells. Mice exposed to ozone experienced increased airway inflammatory cell infiltration and bronchial hyper-responsiveness compared to control mice. Additionally, CLDN3, CLDN4, ROS, Nrf2, and Keap1 protein expression increased, and lung CLDN14 protein expression decreased, in mice exposed to ozone compared with control mice. These results indicate that CLDNs are involved in airway inflammation following ozone exposure, suggesting that ozone affects TJ proteins through oxidative mechanisms.

Glutathione deficiency sensitizes cultured embryonic mouse ovaries to benzo[a]pyrene-induced germ cell apoptosis

Mice lacking the modifier subunit of glutamate cysteine ligase (Gclm), the rate-limiting enzyme in glutathione (GSH) synthesis, have decreased tissue GSH. We previously showed that Gclm-/- embryos have increased sensitivity to the prenatal in vivo ovarian toxicity of the polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) compared with Gclm+/+ littermates. We also showed that BaP-induced germ cell death in cultured wild type embryonic ovaries is caspase-dependent. Here, we hypothesized that GSH deficiency increases sensitivity of cultured embryonic ovaries to BaP-induced germ cell death. 13.5 days post coitum (dpc) embryonic ovaries of all Gclm genotypes were fixed immediately or cultured for 24 h in media supplemented with DMSO vehicle or 500 ng/ml BaP. The percentage of activated caspase-3 positive germ cells varied significantly among groups. Within each genotype, DMSO and BaP-treated groups had increased germ cell caspase-3 activation compared to uncultured. Gclm+/- ovaries had significantly increased caspase-3 activation with BaP treatment compared to DMSO, and caspase-3 activation increased non-significantly in Gclm-/- ovaries treated with BaP compared to DMSO. There was no statistically significant effect of BaP treatment on germ cell numbers at 24 h, consistent with our prior observations in wild type ovaries, but Gclm-/- ovaries in both cultured groups had lower germ cell numbers than Gclm+/+ ovaries. There were no statistically significant BaP-treatment or genotype-related differences among groups in lipid peroxidation and germ cell proliferation. These data indicate that Gclm heterozygous or homozygous deletion sensitizes embryonic ovaries to BaP- and tissue culture-induced germ cell apoptosis.