NADPH Oxidase Activity Research Articles

Chelator Iminodisuccinic Acid Regulates Reactive Oxygen Species Accumulation and Improves Maize (Zea mays L.) Seed Germination under Pb Stress

To explore the effects of iminodisuccinic acid (a chelating agent) on maize (Zea mays L.) seed germination under lead (Pb) stress, we comparatively analyzed the effects of applying different concentrations of iminodisuccinic acid (0, 5, 20, and 100 mmol·dm−3) and combined an addition of exogenous substances regulating reactive oxygen species production on maize seed germination, seedling growth, H2O2 content, NADPH oxidase activity, and antioxidant enzyme activities under Pb-stressed and Pb-free conditions. Iminodisuccinic acid (100 mmol·dm−3) significantly delayed seed germination under normal germination conditions and alleviated the inhibitory effects of Pb stress (20 mmol·dm−3) on seed germination. Under normal conditions (without Pb stress), the iminodisuccinic acid-induced inhibition of seed germination was enhanced by treatment with dimethylthiourea (a specific scavenger of reactive oxygen species) or diphenyleneiodonium chloride (a specific inhibitor of NADPH oxidase), but diminished by treatment with H2O2, CaCl2, diethyldithiocarbamic acid (a specific inhibitor of superoxide dismutase), or aminotriazole (a specific inhibitor of catalase). Under Pb stress, iminodisuccinic acid partially eliminated the excessive H2O2 accumulation, improved superoxide dismutase and catalase activity, and weakened the high NADPH oxidase activity. In addition, Ca2+ chelation may be essential for maintaining the reactive oxygen species’ balance and improving seed germination and seedling growth by iminodisuccinic acid supplementation in maize under Pb stress. The proposed iminodisuccinic acid supplementation-based method improved maize seed germination in Pb-polluted soil.

Thermostable Superoxide-Producing Complex Between NADPH-Containing Lipoprotein (NCL) And Fe (III) From Boiled Cow Milk: Activation Of Immune Cells NADPH Oxidase By NCL In Vitro

О2−-producing complexes or associates have recently been isolated from blood serum, goat milk, erythrocyte, leukocyte membranes, and medicinal plant membranes. Fe(III) ions in these complexes act as bridges for electron transfer from NADPH-containing lipoprotein (NCL) to molecular oxygen, reducing it up to О2−. On the other hand, NADPH oxidase (Nox) of erythrocytes and leukocytosis are activated by NCL in vitro. In fact, both serum and milk contain NCL. The main systems for the production of О2− in mammalian milk and blood, as previously stated, are polymorphonuclear leukocytes, as well as О2−-producing complex between NCL and Fe (III). At the same time, Fe(III) ions can be found in milk, and anemia can result from a Fe(III) deficiency in milk. The superoxide (О2−) - producing thermostable complex between NCL and Fe(III): NCL-Fe(III) was isolated and purified from raw and boiled cow milk, for the first time. The specific О2−-producing activity of NCL-Fe(III) complex from milk, before and after boiling, practically does not change as a result of milk boiling (this activity decreases by only 7-8%). After incubating an aqueous mixture of NCL (5 mg/ml) with an aqueous solution of Nox1 + Nox2 (erythrocytes or leukocytes membranes) isoforms, 5 mg/ml, at 37°C for 40 minutes, an ion exchange chromatography was performed on the column of DE cellulose, equilibrated by water at pH9.5. The hNCL-Nox associate eluates from this column with water at pH9.5 The specific О2−-producing activity of hNCL-Nox isoforms of EM and LM basically does not decrease when compared to the NCL-Fe(III) complex. This is a promising finding, suggesting that milk NCL has stimulating the Nox from erythrocytes or leukocyte membranes in vitro does not decrease even after boiling. In contrast to these О2−-producing associates or complexes, NCL isolated from them, suppresses the oxidation of adrenaline to adrenochrome, exerting a reducing-antioxidant effect due to NADPH electrons in its composition (the Cu, Zn-SOD does not inhibit this process). The NCL isolated from this complex, at the expense of NADPH, has a reductive (antioxidant) influence and forms a hybrid О2−-producing associate with isoforms of the NADPH oxidase from erythrocytes and leukocytes membranes. Thus the properties of the thermostable complex NCL-Fe(III): О2−-producing activity, as well as the reductive (antioxidant) activity of NCL, are practically preserved after milk boiling during 10-12 min.

Chitooligosaccharide Maintained Cell Membrane Integrity by Regulating Reactive Oxygen Species Homeostasis at Wounds of Potato Tubers during Healing.

Chitooligosaccharide (COS) is a degradation product of chitosan. Although COS increased fruit resistance by regulating the metabolism of reactive oxygen species (ROS), few reports are available on whether COS regulates ROS homeostasis at wounds of potato tubers during healing. In this study, COS increased gene expression and activities of NADPH oxidase and superoxide dismutase, and promoted the generation of O2●− and H2O2. Moreover, COS increased gene expression and activities of catalase, peroxidase, and AsA–GSH cycle-related enzymes, as well as the levels of ascorbic acid and glutathione levels. In addition, COS elevated the scavenging ability of DPPH, ABTS+, and FRAP, and reduced cell membrane permeability and malondialdehyde content. Taken together, COS could maintain cell membrane integrity by eliminating excessive H2O2 and improving the antioxidant capacity in vitro, which contributes to the maintainance of cell membrane integrity at wounds of potato tubers during healing.

Disparate Roles of Oxidative Stress in Rostral Ventrolateral Medulla in Age-Dependent Susceptibility to Hypertension Induced by Systemic l-NAME Treatment in Rats.

This study aims to investigate whether tissue oxidative stress in the rostral ventrolateral medulla (RVLM), where sympathetic premotor neurons reside, plays an active role in age-dependent susceptibility to hypertension in response to nitric oxide (NO) deficiency induced by systemic l-NAME treatment, and to decipher the underlying molecular mechanisms. Systolic blood pressure (SBP) and heart rate (HR) in conscious rats were recorded, along with measurements of plasma and RVLM level of NO and reactive oxygen species (ROS), and expression of mRNA and protein involved in ROS production and clearance, in both young and adult rats subjected to intraperitoneal (i.p.) infusion of l-NAME. Pharmacological treatments were administered by oral gavage or intracisternal infusion. Gene silencing of target mRNA was made by bilateral microinjection into RVLM of lentivirus that encodes a short hairpin RNA (shRNA) to knock down gene expression of NADPH oxidase activator 1 (Noxa1). We found that i.p. infusion of l-NAME resulted in increases in SBP, sympathetic neurogenic vasomotor activity, and plasma norepinephrine levels in an age-dependent manner. Systemic l-NAME also evoked oxidative stress in RVLM of adult, but not young rats, accompanied by augmented enzyme activity of NADPH oxidase and reduced mitochondrial electron transport enzyme activities. Treatment with L-arginine via oral gavage or infusion into the cistern magna (i.c.), but not i.c. tempol or mitoQ10, significantly offset the l-NAME-induced hypertension in young rats. On the other hand, all treatments appreciably reduced l-NAME-induced hypertension in adult rats. The mRNA microarray analysis revealed that four genes involved in ROS production and clearance were differentially expressed in RVLM in an age-related manner. Of them, Noxa1, and GPx2 were upregulated and Duox2 and Ucp3 were downregulated. Systemic l-NAME treatment caused greater upregulation of Noxa1, but not Ucp3, mRNA expression in RVLM of adult rats. Gene silencing of Noxa1 in RVLM effectively alleviated oxidative stress and protected adult rats against l-NAME-induced hypertension. These data together suggest that hypertension induced by systemic l-NAME treatment in young rats is mediated primarily by NO deficiency that occurs both in vascular smooth muscle cells and RVLM. On the other hand, enhanced augmentation of oxidative stress in RVLM may contribute to the heightened susceptibility of adult rats to hypertension induced by systemic l-NAME treatment.

Phenol-soluble modulin α and β display divergent roles in mice with staphylococcal septic arthritis

Phenol-soluble modulin α (PSMα) is identified as potent virulence factors in Staphylococcus aureus (S. aureus) infections. Very little is known about the role of PSMβ which belongs to the same toxin family. Here we compared the role of PSMs in S. aureus-induced septic arthritis in a murine model using three isogenic S. aureus strains differing in the expression of PSMs (Newman, Δpsmα, and Δpsmβ). The effects of PSMs on neutrophil NADPH-oxidase activity were determined in vitro. We show that the PSMα activates neutrophils via the formyl peptide receptor (FPR) 2 and reduces their NADPH-oxidase activity in response to the phorbol ester PMA. Despite being a poor neutrophil activator, PSMβ has the ability to reduce the neutrophil activating effect of PSMα and to partly reverse the effect of PSMα on the neutrophil response to PMA. Mice infected with S. aureus lacking PSMα had better weight development and lower bacterial burden in the kidneys compared to mice infected with the parental strain, whereas mice infected with bacteria lacking PSMβ strain developed more severe septic arthritis accompanied with higher IL-6 and KC. We conclude that PSMα and PSMβ play distinct roles in septic arthritis: PSMα aggravates systemic infection, whereas PSMβ protects arthritis development.

Exercise Training Ameliorates Renal Oxidative Stress in Rats with Chronic Renal Failure.

In patients with chronic kidney disease, exercise training with moderate intensity protects renal function and improves mortality. However, the mechanisms of the renal protective effects of exercise training in chronic kidney disease have not been clarified. This study investigated the effects of exercise training on renal NADPH oxidative and xanthine oxidase, which are major sources of reactive oxygen species, in rats with chronic renal failure. Six-week-old, male Sprague–Dawley rats were divided into the sham operation, 5/6 nephrectomy (Nx)+ sedentary, and Nx+ exercise training groups. The Nx+ exercise training group underwent treadmill running. After 12 weeks, systolic blood pressure, renal function, malondialdehyde, renal NADPH oxidase, and xanthine oxidase were examined. Nx induced hypertension, proteinuria, and renal dysfunction, and exercise training attenuated these disorders. Although the plasma levels of malondialdehyde were not different among the group, urinary levels were increased by Nx and decreased by exercise training. Renal activity and expression of NADPH oxidase and xanthine oxidase were increased by Nx and decreased by exercise training. These results indicate that exercise training attenuates hypertension and renal dysfunction and ameliorates NADPH oxidase and xanthine oxidase in rats with chronic renal failure, suggesting that the reduction of reactive oxygen species generation may be involved in the renal protective effects of exercise training.

TBHQ attenuates podocyte injury in diabetic nephropathy by inhibiting NADPH oxidase-derived ROS generation via the Nrf2/HO-1 signalling pathway

AimsOxidative stress plays a crucial role in podocyte injury in diabetic nephropathy (DN). tert-Butylhydroquinone (tBHQ) is an activator of Nrf2 that exerts protective effects in diabetic mice, but the underlying mechanism of tBHQ in the podocytes of DN is not fully understood. Materials and methodsA high glucose (HG)-induced HK2 cell model and streptozotocin-induced rat model of DN were established and treated with tBHQ or apocynin. The expression levels of Nrf2, HO-1, NOX2 and NOX4 were determined by Western blot or immunohistochemical staining. The level of oxidative stress in podocytes or kidney tissues was assessed using DCFH-DA or dihydroethidium (DHE) staining. Cell injury was assessed by F-actin staining and flow cytometry analysis. Key findingsWe showed that HG treatment increased the expressions of NOX2 and NOX4 and enhanced ROS production in podocytes. Inhibition of NADPH oxidase activity by apocynin dramatically attenuated HG-induced ROS production and further alleviated cell injury and apoptosis in podocytes. Moreover, we found that HG inhibited the Nrf2/HO-1 signalling pathway in podocytes; however, tBHQ treatment significantly activated the Nrf2 signalling pathway, inhibited NADPH oxidase activity, and attenuated ROS production and cell injury in HG-treated podocytes. Furthermore, we observed that tBHQ treatment partially attenuated renal injury, activated the Nrf2 signalling pathway, inhibited NADPH oxidase activity and reduced ROS generation in the kidneys of STZ-induced diabetic rats. SignificanceThese results suggest that tBHQ exerts a protective role in hyperglycaemia-induced podocyte injury, and that the potential protective mechanism of tBHQ involves inhibiting NADPH oxidase-derived ROS generation by activating the Nrf2/HO-1 signalling pathway.

Vaspin Ameliorates Cardiac Remodeling by Suppressing Phosphoinositide 3-Kinase/Protein Kinase B Pathway to Improve Oxidative Stress in Heart Failure Rats.

:This study aimed to explore whether vaspin could alleviate cardiac remodeling through attenuating oxidative stress in heart failure rats and to determine the associated signaling pathway. Cardiac remodeling was induced by myocardial infarction, transverse aortic constriction, or angiotensin (Ang) II infusion in vivo, and the neonatal rat cardiomyocytes (NRCMs) and neonatal rat cardiac fibroblasts (NRCFs) were treated with Ang II. Vaspin treatment alleviated fibrosis in myocardial infarction, transverse aortic constriction, and Ang II-treated rats. The Ang II-induced increases of atrial natriuretic peptide and brain natriuretic peptide in NRCMs and Ang II-induced increases of collagen I and collagen III in NRCFs were reduced after vaspin treatment. Vaspin administration inhibited the Ang II-induced increases of phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) pathway, superoxide anions, malondialdehyde, and NADPH oxidases activity in NRCMs and NRCFs. The overexpression of PI3K, Akt, or NADPH oxidases 1 reversed the attenuating effects of vaspin on Ang II-induced elevation of atrial natriuretic peptide and brain natriuretic peptide in NRCMs, as well as Ang II-induced increases of collagen I and collagen III in NRCFs. The administration of wortmannin (PI3K inhibitor) or MK2206 (Akt inhibitor) inhibited the oxidative stress induced by Ang II in NRCMs and NRCFs. The above results suggest that vaspin can alleviate cardiac dysfunction and remodeling in heart failure rats. Vaspin attenuates Ang II-induced hypertrophy of NRCMs and fibrosis of NRCFs through suppressing PI3K/Akt pathway to alleviate oxidative stress.

Tumstatin (69–88) alleviates heart failure via attenuating oxidative stress in rats with myocardial infarction

BackgroundThis study aimed to elucidate the effects of tumstatin (69–88) on heart failure and the underlying mechanism. Materials and methodsMyocardial infarction (MI) was induced by ligating the left coronary artery in rats to trigger heart failure. ResultsTumstatin (69–88) can reduce cardiac insufficiency in rats with heart failure. The increased cardiac fibrosis in MI rat was attenuated by tumstatin (69–88). Increase of cardiac atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in rats with myocardial infarction, and Ang II-treated NRCMs or H9C2 cells was inhibited by tumstatin (69–88). In the heart of MI rats, and Ang II-treated NRCMs or H9C2 cells, the superoxide anions and NADPH oxidase (Nox) activity rose and the superoxide dismutase (SOD) activity was reduced, which was inhibited by tumstatin (69–88). Diethyldithiocarbamate, an SOD inhibitor, increased the ANP and BNP in NRCMs or H9C2 cells. Tumstatin (69–88) inhibited the Ang II-induced raises of ANP and BNP in NRCMs or H9C2 cells, which was reversed by DETC. ConclusionsThese results indicate that tumstatin (69–88) alleviates cardiac dysfunction of heart failure. Tumstatin (69–88) improves the hypertrophy of cardiomyocytes via attenuation of oxidative stress. Tumstatin (69–88) may be a potential drug for heart failure in the future.

Abstract 078: Human Gain-of-function Mutation W521r In The Enac α-subunit Contributes To Salt-sensitive Hypertension In A Sex-specific Manner

The epithelial Na + channel (ENaC) plays a key role in regulating the extracellular fluid volume and blood pressure. Gain-of-function mutations in ENaC subunits are associated with hypertensive disorders including Liddle syndrome. We previously demonstrated that in male mice, dendritic cell ENaC mediates NADPH oxidase activation and increased accumulation of Isolevuglandins (IsoLGs), which act as neoantigens, promoting T cell activation and salt-induced hypertension. The mechanism by which dendritic cell ENaC is regulated, and the role of sex as a biological variable is still yet to be defined. One of the mechanisms by which ENaC is regulated is through sodium self-inhibition. We hypothesized that sodium self-inhibition plays a sex-specific role in regulating ENaC leading to salt-sensitive hypertension. To test this hypothesis, we generated mice with a gain-of-function mutation of a single nucleotide variant (W521R) in ENaC α-subunit using CRISPR/Cas9 in the wild-type (WT) salt-sensitive129/sv background. These mutant mice lack the sodium self-inhibition of ENaC. WT littermate male and female mice were used as controls. Using telemetry blood pressure monitoring, we found that WT males developed salt-induced hypertension, but WT females were protected (124.3 ± 5.15 vs. 95.37 ± 4.882 mmHg, p=0.0114). Moreover, W521R male mutants had elevated mean arterial pressure in response to 3 weeks of high salt-feeding (4% NaCl) compared to the salt-sensitive WT littermate males (169.3 ± 27.69 vs. 124.3 ± 5.15 mmHg, p= 0.0024). Similar to WT females, female W521R mice were protected from salt-induced blood pressure elevation (102.3± 5.23 mmHg). Using flow cytometry, we found that high Na + increased dendritic cell IsoLGs production in male W521R mice compared to littermate controls (3.97 ± 1.68% vs. 1.01 ± 0.08 % of dendritic cells, p=0.0386). Our findings suggest that W521R gain-of-function mutation contributes to inflammation and hypertension in male but not female mice.

Exercise Improves Redox Homeostasis and Mitochondrial Function in White Adipose Tissue.

Exercise has beneficial effects on energy balance and also improves metabolic health independently of weight loss. Adipose tissue function is a critical denominator of a healthy metabolism but the adaptation of adipocytes in response to exercise is insufficiently well understood. We have previously shown that one aerobic exercise session was associated with increased expression of antioxidant and cytoprotective genes in white adipose tissue (WAT). In the present study, we evaluate the chronic effects of physical exercise on WAT redox homeostasis and mitochondrial function. Adult male Wistar rats were separated into two groups: a control group that did not exercise and a group that performed running exercise sessions on a treadmill for 30 min, 5 days per week for 9 weeks. Reactive oxygen species (ROS) generation, antioxidant enzyme activities, mitochondrial function, markers of oxidative stress and inflammation, and proteins related to DNA damage response were analyzed. In WAT from the exercise group, we found higher mitochondrial respiration in states I, II, and III of Complex I and Complex II, followed by an increase in ATP production, and the ROS/ATP ratio when compared to tissues from control rats. Regarding redox homeostasis, NADPH oxidase activity, protein carbonylation, and lipid peroxidation levels were lower in WAT from the exercise group when compared to control tissues. Moreover, antioxidant enzymatic activity, reduced glutathione/oxidized glutathione ratio, and total nuclear factor erythroid-2, like-2 (NFE2L2/NRF2) protein levels were higher in the exercise group compared to control. Finally, we found that exercise reduced the phosphorylation levels of H2AX histone (γH2AX), a central protein that contributes to genome stability through the signaling of DNA damage. In conclusion, our results show that chronic exercise modulates redox homeostasis in WAT, improving antioxidant capacity, and mitochondrial function. This hormetic remodeling of adipocyte redox balance points to improved adipocyte health and seems to be directly associated with the beneficial effects of exercise.

Taurine inhibits Streptococcus uberis-induced NADPH oxidase-dependent neutrophil extracellular traps via TAK1/MAPK signaling pathways

Neutrophil extracellular traps (NETs) are produced by neutrophil activation and usually have both anti-infective and pro-damage effects. Streptococcus uberis (S. uberis), one of the common causative organisms of mastitis, can lead to the production of NETs. Taurine, a free amino acid abundant in the organism, has been shown to have immunomodulatory effects. In this study, we investigated the molecular mechanisms of S. uberis-induced NETs formation and the regulatory role of taurine. The results showed that NETs had a disruptive effect on mammary epithelial cells and barriers, but do not significantly inhibit the proliferation of S. uberis. S. uberis induced NADPH oxidase-dependent NETs. TLR2-mediated activation of the MAPK signaling pathway was involved in this process. Taurine could inhibit the activation of MAPK signaling pathway and NADPH oxidase by modulating the activity of TAK1, thereby inhibiting the production of ROS and NETs. The effects of taurine on NADPH oxidase and NETs in S. uberis infection were also demonstrated in vivo. These results suggest that taurine can protect mammary epithelial cells and barriers from damage by reducing S. uberis-induced NETs. These data provide new insights and strategies for the prevention and control of mastitis.

Crosstalk between neuroinflammation and oxidative stress in epilepsy.

The roles of both neuroinflammation and oxidative stress in the pathophysiology of epilepsy have begun to receive considerable attention in recent years. However, these concepts are predominantly studied as separate entities despite the evidence that neuroinflammatory and redox-based signaling cascades have significant crosstalk. Oxidative post-translational modifications have been demonstrated to directly influence the function of key neuroinflammatory mediators. Neuroinflammation can further be controlled on the transcriptional level as the transcriptional regulators NF-KB and nrf2 are activated by reactive oxygen species. Further, neuroinflammation can induce the increased expression and activity of NADPH oxidase, leading to a highly oxidative environment. These factors additionally influence mitochondria function and the metabolic status of neurons and glia, which are already metabolically stressed in epilepsy. Given the implication of this relationship to disease pathology, this review explores the numerous mechanisms by which neuroinflammation and oxidative stress influence one another in the context of epilepsy. We further examine the efficacy of treatments targeting oxidative stress and redox regulation in animal and human epilepsies in the literature that warrant further investigation. Treatment approaches aimed at rectifying oxidative stress and aberrant redox signaling may enable control of neuroinflammation and improve patient outcomes.

Hypertension secondary to nitric oxide depletion produces oxidative imbalance and inflammatory/fibrotic outcomes in the cornea of C57BL/6 mice

Arterial hypertension (AH) leads to oxidative and inflammatory imbalance that contribute to fibrosis development in many target organs. Here, we aimed to highlight the harmful effects of severe AH in the cornea. Our experimental model was established by administration of NG-nitro-L-arginine-methyl-ester (L-NAME) to C57BL/6 mice, which were monitored weekly for arterial blood pressure and intraocular pressure (IOP). Morphological studies of ocular tissues were accompanied by analyses of reactive oxygen species generation, and localization/expression of NAPDH oxidase isoforms (NOX1, NOX2, NOX4) and inflammatory biomarkers (PPARα, PPARγ, IL-1β, IL-6, IL-10, TNF-α, and COX-2). Masson’s trichrome and Sirius Red staining were used to explore the fibrotic status of the cornea. The expression of collagen isoforms (COL1α1, COL1α2, COL3α1, COL4α1, COL4α2) and relevant metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) were also quantified to evaluate the participation of collagen metabolism in AH-related corneal damage. Hypertensive animals showed an increase in IOP values, and a thinner cornea compared with normotensive controls. Moreover, AH increased NADPH oxidase activity and reactive oxygen species generation in the cornea, which was accompanied by transcriptional upregulation of NOX isoforms and inflammatory biomarkers, while reducing PPAR expression. L-NAME-treated animals also developed corneal fibrosis with overexpression of collagen isoforms and reduction of factors responsible for collagen degradation. This is the first study reporting structural changes in the cornea and elevated IOP in L-NAME-treated mice. Overexpression of the NADPH oxidase system and collagen deposition might play a substantial role in the pathogenic mechanisms contributing to ocular disturbances in a context of severe hypertension.

Post-harvest chitosan treatment suppresses oxidative stress by regulating reactive oxygen species metabolism in wounded apples.

Mechanical wound on fruit triggers the formation of reactive oxygen species (ROS) that weaken cell walls, resulting in post-harvest losses. This mechanism can be controlled by using fruit preservatives to stimulate fruit antioxidant enzyme activities for the detoxification of ROS. Chitosan is a safe and environmentally friendly preservative that modulates ROS in whole fruits and plant cells, but the effects of chitosan on the ROS metabolism of mechanically wounded apples during storage are unknown. Our study focused on exploring the effects of post-harvest chitosan treatment on ROS production, cell membrane integrity, and enzymatic and non-enzymatic antioxidant systems at fruit wounds during storage. Apple fruits (cv. Fuji) were artificially wounded, treated with 2.5% (w/v) chitosan, and stored at room temperature (21–25°C, RH = 81–85%) for 7 days. Non-wounded apples were used as healthy controls. The results showed that chitosan treatment stimulated the activities of NADPH oxidase and superoxide dismutase and increased the formation of superoxide anions and hydrogen peroxide in fruit wounds. However, malondialdehyde, lipoxygenase, and membrane permeability, which are direct biomarkers to evaluate lipid peroxidation and membrane integrity, were significantly decreased in the wounded fruits after chitosan treatment compared to the wounded control fruits. Antioxidant enzymes, such as peroxidase and catalase activities, were induced by chitosan at fruit wounds. In addition, ascorbate-glutathione cycle-related enzymes; ascorbate peroxide, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase and the content of substrates, mainly ascorbic acid, dehydroascorbate, reduced glutathione, and glutathione, were increased at fruit wounds by chitosan compared to the wounded control fruits. Our results show that wounding stimulated the production of ROS or oxidative stress. However, treatment with chitosan triggered antioxidant systems to scavenge ROS and prevent loss of fruit membrane integrity. Therefore, chitosan promises to be a favorable preservative in inducing tolerance to stress and maintaining fruit quality.

Diet-induced obesity impairs spermatogenesis: the critical role of NLRP3 in Sertoli cells

BackgroundAccumulating evidence indicates a key role of Sertoli cell (SC) malfunction in spermatogenesis impairment induced by obesity. Nucleotide-binding oligomerization domain-like receptor with a pyrin domain 3 (NLRP3) is expressed in SCs, but the role of NLRP3 in the pathological process of obesity-induced male infertility remains unclear.MethodsNLRP3-deficient mice were fed a high-fat diet for 24 weeks to establish obesity-related spermatogenesis impairment. In another set of experiments, a lentiviral vector containing a microRNA (miR)-451 inhibitor was injected into AMP-activated protein kinase α (AMPKα)-deficient mouse seminiferous tubules. Human testis samples were obtained by testicular puncture from men with obstructive azoospermia whose samples exhibited histologically normal spermatogenesis. Isolated human SCs were treated with palmitic acid (PA) to mimic obesity model in vitro.ResultsIncreased NLRP3 expression was observed in the testes of obese rodents. NLRP3 was also upregulated in PA-treated human SCs. NLRP3 deficiency attenuated obesity-related male infertility. SC-derived NLRP3 promoted interleukin-1β (IL-1β) secretion to impair testosterone synthesis and sperm performance and increased matrix metalloproteinase-8 (MMP-8) expression to degrade occludin via activation of nuclear factor-kappa B (NF-κB). Increased miR-451 caused by obesity, decreased AMPKα expression and sequentially increased NADPH oxidase activity were responsible for the activation of NLRP3. miR-451 inhibition protected against obesity-related male infertility, and these protective effects were abolished by AMPKα deficiency in mice.ConclusionsNLRP3 promoted obesity-related spermatogenesis impairment. Increased miR-451 expression, impaired AMPKα pathway and the subsequent ROS production were responsible for NLRP3 activation. Our study provides new insight into the mechanisms underlying obesity-associated male infertility.

Disrupting Interleukin 12 Improves Microvascular Endothelial Function in Type 2 Diabetes Through ER Stress CHOP and Oxidative Stress Mechanisms.

PurposeVascular endothelial dysfunction is well established in type 2 diabetes. Interleukin-12 (IL-12) and endoplasmic reticulum (ER) stress are up-regulated in type 2 diabetic patients and animal models of type 2 diabetes. However, the role and underlying mechanisms of IL-12 and the ER stress CHOP in endothelial dysfunction are not fully understood.MethodsWe generated double knockout mice between db−/db− and p40IL-12−/− mice (db−/db−p40-IL−12-/-) and endoplasmic (ER) stress-CHOP−/− mice (db−/db−CHOP-/-). We performed a glucose tolerance test (GTT) to determine the effect of IL-12 and ER stress CHOP on glucose metabolism. We assessed the endothelial function and determined the phosphorylation level of eNOS, Akt, AMPK, and the expression of ER stress (CHOP, BIP), and oxidative stress (Nox2 and Nox4 and NADPH oxidase activity).ResultsThe results showed that GTT was improved in db-/db−p40-IL−12-/- and db−/db−CHOP-/- suggesting IL-12 and CHOP as parts of a mechanism involved in the development of type 2 diabetes. The microvascular endothelial dysfunction in db−/db− mouse is associated with decreased phosphorylated eNOS, Akt, AMPK, and increased CHOP, BIP, Nox2, and Nox4 expressions. Interestingly, disrupting IL-12 and ER stress CHOP in db−/db− mice significantly improved endothelial function, increased survival markers expression and decreased ER and oxidative stress.ConclusionUsing a genetic approach, these findings provide evidence that IL-12 and ER stress CHOP play a significant role in microvascular endothelial dysfunction in type 2 diabetes.

YIA] Changes in NADPH oxidase activity in E-cigarette vapor condensate exposed cultured cells and the role of acrolein

YIA] Changes in NADPH oxidase activity in E-cigarette vapor condensate exposed cultured cells and the role of acrolein

Trimetazidine Reduces Cardiac Fibrosis in Rats by Inhibiting NOX2-Mediated Endothelial-to-Mesenchymal Transition.

PurposeEndothelial-to-mesenchymal transition (EndMT) is an important mechanism underlying cardiac fibrosis. The anti-ischemic drug trimetazidine (TMZ) is reportedly useful in ventricular remodeling and associated with NADPH oxidase (NOX) 2. This study aimed to investigate the possible effect of TMZ on cardiac fibrosis exerted via the inhibition of NOX2-mediated EndMT.MethodsA cardiac fibrosis model was established in Sprague-Dawley rats through a subcutaneous injection of isoproterenol (ISO, 5 mg/kg/d). Echocardiographic parameters, myocardial fibrosis, NOX2 expression and EndMT were assessed. An in vitro model of EndMT was developed using human umbilical vein endothelial cells (HUVECs) via treatment with transforming growth factor-β (TGF-β) at 10 ng/mL for 24 h. HUVECs were administrated with TMZ or TMZ and lentivirus, the expression of EndMT and related proteins was observed by wound healing assay, immunoblotting, and immunofluorescence.ResultsRats injected with ISO exhibited severe interstitial cardiac fibrosis and perivascular fibrosis, decreased left ventricular ejection fraction, and increased NOX activity. TMZ treatment mitigated cardiac fibrosis, ameliorated left ventricular dysfunction, and reduced NOX activity. In addition, TMZ effectively inhibited EndMT in ISO-treated rat hearts and TGF-β-treated HUVECs, as manifested by increased CD31 expression, decreased α-SMA expression, and suppressed cell migration. Compared with the control group, the expression of NOX2, nuclear factor-κB (NF-κB), and Snail was increased in vivo and in vitro but decreased with TMZ treatment. Furthermore, the overexpression of NOX2 by lentivirus abolished the protective effects of TMZ on TGF-β-induced EndMT.ConclusionTMZ may ameliorate EndMT and ISO-induced cardiac fibrosis through the NOX2/NF-κB/Snail pathway. The findings of the study may provide new insights into the potential role of TMZ in the pathophysiology of cardiac fibrosis.

Light-driven activation of NADPH oxidases

<p indent="0mm">NADPH oxidases (NOX) expressed in multiple cell types after activation produce superoxide or hydrogen peroxide to modulate several physiological and pathophysiological processes. The ultraviolet A (UVA) band in solar irradiation activates NOX1 in skin keratinocytes and NOX2 in mast cells. Whereas NOX1 and NOX2 are oligomeric, NOX5 is monomeric, and DUOX2 is dimeric. NOX5, like all other NOX isozymes, contains chromophores heme, NADPH, and FAD. Both NADPH and FAD are endogenous photosensitizers, which undergo type II photodynamic action to produce singlet oxygen after absorption of UVA irradiation. In this review, we propose that UVA irradiation activates all NOX isoforms leading to their irreversible activation. Type II photodynamic action of endogenous chromophores/photosensitizers plays a critical role in such UVA light-driven NOX activation.