Enzyme Nicotinamide Adenine Dinucleotide Phosphate Research Articles

Bioactive peptides derived from the enzymatic hydrolysis of cowhide collagen for the potential treatment of atherosclerosis: A computational approach

Cowhide collagen hydrolysates (CCHs) are peptides and amino acids obtained from the partial hydrolysis of collagen. These have numerous potential applications in the food, biomedical, and pharmaceutical industries. The study analyzed the physicochemical, antioxidant, and anti-atherosclerosis properties of collagen hydrolysates (CCHs) from cowhide using in silico methods. Proteins were identified in silico based on their molecular weights and origin from the protein database (UniProtKB). Using bioinformatics tools, numerous physicochemical properties (toxicity and amino acid composition) were determined. The identified proteins were subsequently subjected to an in silico enzymatic hydrolysis using pepsin, thermolysin, and proteinase K. The peptides obtained were characterized. Molecular docking was conducted between the peptides generated in silico and the three target enzymes (3-Hydroxy-3-Methylglutaryl-CoA (HMG-CoA) reductase, cyclooxygenase-2, and Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase). Two cowhide collagens were identified, F1MJQ6 and G3MZI7, with molecular weights of 172,076 and 184,867 ​Da, respectively. A compositional analysis of F1MJQ6 and G3MZI7 revealed the significant presence of glycine residues at 25 ​% and 23 ​%, and proline residues at 16 ​% and 18 ​%, respectively. The G3MZI7 and F1MJQ6 proteins exhibited a high concentration of both essential and semi-essential amino acids. The molecular docking results indicate that the antioxidant peptides ADF, PHF, and LW (novel potential anti-atherosclerosis peptides released by enzymatic hydrolysis with pepsin, thermolysin, and proteinase K) are the most promising candidates for further development as inhibitors of HMG-CoA reductase, cyclo-oxygenase-2, and NADPH oxidase. In silico analysis revealed that cowhide collagen hydrolysates exhibited particularly significant antioxidant and anti-atherosclerosis properties.

Antioxidant insights of wild olive (acebuche) oil ophthalmic nanoemulsions against arterial hypertension

Aims/Purpose: Many systemic and ocular disturbances are closely related to oxidative stress, including hypertensive eye diseases. In this context, the oral administration of wild olive oil, also known as acebuche (ACE) oil (Olea europaea var. sylvestris), proved to modulate local production of reactive oxygen species (ROS) by the enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase1. Here we aimed to develop an ophthalmic formulation based on ACE oil as a localized therapy against oxidative damage associated with arterial hypertension (AH).Methods: Nanoemulsions (NEs) of ACE oil were successfully produced, characterized, and evaluated in vivo in terms of efficacy. The antioxidant properties of these NEs were tested in mice with AH induced via administration of Nω‐nitro‐L‐arginine‐methyl‐ester (L‐NAME), which underwent intravitreal or topical ophthalmic treatment with ACE oil NEs. At the end of the treatments, a histological analysis of the cornea and retina was performed together with an evaluation of the activity/expression of NADPH oxidase in these ocular tissues.Results: Adequate ophthalmic formulations were designed to present the features for ophthalmic administration, including a nanometre size (below 200 nm), moderate negative ZP, adequate osmolality and pH, among others. Histological analysis indicated that NEs reduced hypertension‐dependent morphological alterations in the cornea and retina. Furthermore, the evaluation of the activity and expression of NADPH oxidase suggest a noticeable antioxidant effect of NEs through downregulation of NOX1, NOX2 and NOX4 isoforms and counteracting excess ROS production in the hypertensive eye.Conclusions: Topical administration, via intravitreal or drop instillation, of an ophthalmic formulation based on ACE oil NEs might show promise against ocular pathologies related to AH. Interestingly, this therapeutical approach provided better outcomes compared to long‐term dietary administration of the oil, both in terms of cumulative dose and treatment time required.

Ophthalmic wild olive (ACEBUCHE) oil nanoemulsions exert oculoprotective effects against oxidative stress induced by arterial hypertension

Oxidative stress plays a key role in several systemic and ocular diseases, including hypertensive eye diseases. In this context, we previously showed that oral administration of wild olive (acebuche, ACE) oil from Olea europaea var. sylvestris can counteract ocular damage secondary to arterial hypertension by modulating excess reactive oxygen species (ROS) produced by the enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Therefore, this work describes the development of an ACE oil-based formulation for ocular administration as a local therapy to counteract hypertension-related oxidative damage. Specifically, ACE oil nanoemulsions (NEs) were successfully produced and characterized, exhibiting appropriate features for ophthalmic administration, including a nanometer size (<200 nm), moderate negative ZP, adequate osmolality and pH, and colloidal stability in biorelevant fluids. Likewise, the NEs presented a shear thinning behavior, especially convenient for ocular instillation. In vivo evaluation was performed through either intravitreal injection or topical ophthalmic administration in mice with hypertension induced via administration of Nω-nitro-L-arginine-methyl-ester (L-NAME). Both routes of administration reduced hypertensive morphological alterations and demonstrated a noticeable antioxidant effect thanks to the reduction of the activity/expression of NADPH oxidase in cornea and retina. Thus, an ACE oil ophthalmic formulation represent a promising therapy for ocular pathologies associated with arterial hypertension.

Reactive Oxygen Species Are Central Mediators of Vascular Dysfunction and Hypertension Induced by Ethanol Consumption.

Consumption of high amounts of ethanol is a risk factor for development of cardiovascular diseases such as arterial hypertension. The hypertensive state induced by ethanol is a complex multi-factorial event, and oxidative stress is a pathophysiological hallmark of vascular dysfunction associated with ethanol consumption. Increasing levels of reactive oxygen species (ROS) in the vasculature trigger important processes underlying vascular injury, including accumulation of intracellular Ca2+ ions, reduced bioavailability of nitric oxide (NO), activation of mitogen-activated protein kinases (MAPKs), endothelial dysfunction, and loss of the anticontractile effect of perivascular adipose tissue (PVAT). The enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase plays a central role in vascular ROS generation in response to ethanol. Activation of the renin-angiotensin-aldosterone system (RAAS) is an upstream mechanism which contributes to NADPH oxidase stimulation, overproduction of ROS, and vascular dysfunction. This review discusses the mechanisms of vascular dysfunction induced by ethanol, detailing the contribution of ROS to these processes. Data examining the association between neuroendocrine changes and vascular oxidative stress induced by ethanol are also reviewed and discussed. These issues are of paramount interest to public health as ethanol contributes to blood pressure elevation in the general population, and it is linked to cardiovascular conditions and diseases.

The effects of sugammadex on gastric ischemia-reperfusion injury in rats: Biochemical and histopathological evaluation.

The primary sources of reactive oxygen species (ROS) that cause ischemia-reperfusion (I/R) injuries are enzymes xanthine oxidase (XO) and nicotinamide adenine dinucleotide phosphate oxidases (NOXs) in the literature, whereby one of the main ROS producing cells via NOX activity are polymophonuclear leukocytes (PNL). Sugammadex, the effect of which we plan to research against gastric I/R damage, is a modified gamma-cyclodextrin that antagonizes the action of steroidal neuromuscular blocking drugs. Previous studies have reported that sugammadex inhibits PNL infiltration. However, it is unknown whether an inhibitory effect on XO is present. We aimed to biochemically and histopathologically investigate the effects of sugammadex on I/R-induced stomach damage in rats. The animals were divided into groups that underwent gastric ischemia-reperfusion (GIR), 4 mg/kg sugammadex + gastric ischemia-reperfusion (SGIR), and a sham operation group (SG). The effect of sugammadex was evaluated by measuring oxidant-antioxidant and PNL parameters. There was no significant difference in XO levels between the SGIR and GIR groups. In the SGIR group, sugammadex inhibited the increase in myeloperoxidase (MPO) and malondialdehyde (MDA) levels (p < 0.001). The amount of MDA and MPO in the SGIR group was similar as in the SG group. Sugammadex significantly suppressed the decrease in tGSH levels in the SGIR group (p < 0.001). The difference between tGSH levels in the SG and SGIR groups was slight. In the SGIR group, sugammadex significantly suppressed the increase in tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL1-β) levels compared to the GIR group (p < 0.001). Additionally, sugammadex corrected histopathological modifications as much as sham group. In conclusion, sugammadex may be beneficial in preventing oxidative stress.

NOX2ko Mice Show Largely Increased Expression of a Mutated NOX2 mRNA Encoding an Inactive NOX2 Protein.

Background: The superoxide-generating enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX2 or gp91phox, the phagocytic isoform) was reported as a major source of oxidative stress in various human diseases. Genetic deletion is widely used to study the impact of NOX2-derived reactive oxygen species (ROS) on disease development and progression in various animal models. Here, we investigate why NOX2 knockout mice show no NOX2 activity but express NOX2 mRNA and protein. Methods and Results: Oxidative burst (NOX2-dependent formation of ROS) was measured by L-012-based chemiluminescence and was largely absent in whole blood of NOX2 knockout mice. Protein expression was still detectable in different tissues of the NOX2 knockout mice, at the expected and a slightly lower molecular weight (determined by Western blot). The NOX2 gene was even largely enhanced at its expressional level in NOX2 knockout mice. RNA sequencing revealed a modified NOX2 mRNA in the knockout mice that is obviously translated to a truncated inactive mutant enzyme. Conclusion: Although the commercial NOX2 knockout mice display no considerable enzymatic NOX2 activity, expression of the NOX2 gene (when using standard primers) and protein (when using antibodies binding to the carboxy-terminal end) can still be detected, which may lead to confusion among investigators.

Effect of the Lipid Peroxidation Product 4-Hydroxynonenal on Neuroinflammation in Microglial Cells: Protective Role of Quercetin and Monochloropivaloylquercetin

The lipid peroxidation-derived aldehyde 4-hydroxynonenal (HNE) has been implicated in a number of oxidative stress-induced inflammatory pathologies such as neurodegenerative diseases and aging. In this regard, we investigated the effects of HNE on neuroinflammatory responses by measuring cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) induction with cytokine production. In addition, we measured nuclear factor erythroid 2-related factor 2 (Nrf-2)/Kelch-like ECH-associated protein 1 (Keap1) signaling proteins, and antioxidant enzymes heme oxygenase-1 (HO-1) and nicotinamide adenine dinucleotide phosphate dehydrogenase, quinone 1 (NQO1), and compared the results with quercetin and monochloropivaloylquercetin (MPQ) pretreated microglial cells. Cytotoxicity was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and production of cytokines was determined by cytokine array. Furthermore, intracellular Nfr2/Keap1 signaling proteins, HO-1, NQO1, and COX-2 expression were analyzed by western blot in 2.5 μM HNE treated BV-2 cells. Inducible nitric oxide synthase (iNOS) and COX-2 mRNA levels were measured with reverse transcription-quantitative polymerase chain reaction. HNE induced both COX-2 mRNA and protein levels, iNOS mRNA expression, and cytokine production. In addition, HNE markedly increased Keap1 levels and decreased cytoplasmic Nrf-2 expression with antioxidant enzyme HO-1 levels. Quercetin and monochloropivaloylquercetin treatment alleviated neuroinflammatory responses in microglial cells, by decreasing COX-2 mRNA expression. Monochloropivaloylquercetin decreased cytoplasmic Keap1 levels and increased nuclear translocation of Nrf-2 resulted in induction of HO-1 and NQO1 expression. These results suggest that HNE could be a link between oxidative stress and inflammation in BV-2 microglia cells. In particular, monochloropivaloylquercetin alleviated inflammation, probably by decreasing the expression of proinflammatory genes and strengthening the antioxidant defense system.

The roles of NADPH oxidase in modulating neutrophil effector responses.

Neutrophils are phagocytic innate immune cells essential for killing bacteria via activation of a wide variety of effector responses and generation of large amounts of reactive oxygen species (ROS). Majority of the ROS in neutrophils is generated by activation of the superoxide-generating enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Independent of their anti-microbial function, NADPH oxidase-derived ROS have emerged as key regulators of host immune responses and neutrophilic inflammation. Data from patients with inherited defects in the NADPH oxidase subunit alleles that ablate its enzyme function as well as mouse models demonstrate profound dysregulation of host inflammatory responses, neutrophil hyper-activation and tissue damage in response to microbial ligands or tissue trauma. A large body of literature now demonstrates how oxidants function as essential signaling molecules that are essential for the regulation of neutrophil responses during priming, degranulation, neutrophil extracellular trap formation, and apoptosis, independent of their role in microbial killing. In this review we summarize how NADPH oxidase-derived oxidants modulate neutrophil function in a cell intrinsic manner and regulate host inflammatory responses. In addition, we summarize studies that have elucidated possible roles of oxidants in neutrophilic responses within the oral mucosa and periodontal disease.

Pathophysiological Alterations of Redox Signaling and Endocannabinoid System in Granulocytes and Plasma of Psoriatic Patients.

Inflammatory granulocytes are characterized by an oxidative burst, which may promote oxidative stress and lipid modification both in affected tissues and on a systemic level. On the other hand, redox signaling involving lipid peroxidation products acting as second messengers of free radicals play important yet not fully understood roles in the pathophysiology of inflammation and various stress-associated disorders. Therefore, the aim of this study was to evaluate the onset of oxidative stress and alterations of enzyme-dependent lipid metabolism resulting from redox imbalance in granulocytes and plasma obtained from patients with psoriasis vulgaris or psoriatic arthritis in comparison to the healthy subjects. The results obtained revealed enhanced activity of pro-oxidant enzymes nicotinamide adenine dinucleotide phosphate (NADPH) and xanthine oxidases in granulocytes with a decrease of enzymatic and non-enzymatic antioxidants in the plasma of psoriatic patients. The nuclear factor erythroid 2–related factor 2 (Nrf2) and its regulators were increased in both forms of psoriasis while heme oxygenase 1 levels were increased only in psoriasis vulgaris. The redox imbalance was associated with decreased levels of phospholipids and of free polyunsaturated fatty acids but with enhanced activity of enzymes involved in lipid metabolism (phospholipase A2, acetylhydrolase PAF, cyclooxygenases 1 and 2) and increased lipid peroxidation products 4-hydroxynonenal, isoprostanes, and neuroprostanes. Increased endocannabinoids and G protein-coupled receptor 55 were observed in both forms of the disease while expression of the cannabinoid type 1 receptor (CB1) was increased only in patients with psoriatic arthritis, which is opposite to the cannabinoid type 2 receptor. This receptor was increased only in psoriasis vulgaris. Changes in protein expression promoted the apoptosis of granulocytes by increased caspases mainly in psoriasis vulgaris. This study indicates that inhibition of the Nrf2 pathway in psoriatic arthritis promotes a redox imbalance. In addition, increased expression of CB1 receptors leads to increased oxidative stress, lipid modifications, and inflammation, which, in turn, may promote the progression of psoriasis into the advanced, arthritic form of the disease.

Baicalin provides neuroprotection in traumatic brain injury mice model through Akt/Nrf2 pathway.

BackgroundThe neuroprotective effects of Baicalin have been confirmed in several central nervous system (CNS) diseases. However, its possible effect on traumatic brain injury (TBI) model is still not clear. The present study is aimed to investigate the role and the underling mechanisms of 7-D-glucuronic acid-5,6-dihydroxyflavone (Baicalin) on TBI model.MethodsThe weight-drop model of TBI in Institute of Cancer Research mice was treated with Baicalin intraperitoneally at 30 minutes after TBI. LY294002 (LY) (a commonly used PI3K/Akt pathway inhibitor) was injected into the left ventricle at 30 minutes before TBI. All mice were euthanized at 24 hours after TBI to collect the brain tissue for a series of tests except for neurological function, which was measured at 2 hours and 1 and 3 days post-TBI.ResultsBaicalin administration significantly improved neurobehavioral function, alleviated brain edema, and reduced apoptosis-positive cells by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay accompanied with the upregulation of B-cell lymphoma 2 (Bcl-2) and downregulation of Bcl-2-associated X protein (Bax) and cleaved-caspase 3 by Western blot. Besides, TBI-induced oxidant stress status was also restored in the Baicalin group by measuring malondialdehyde (MDA) content, glutathione peroxidase (GPx), and superoxide dismutase (SOD) levels in the injured brain cortex. Furthermore, translocation of Nrf2 to the nucleus was dramatically enhanced by Baicalin verified by immunofluorescence and Western blot analyses. Accordingly, its downstream antioxidative enzymes nicotinamide adenine dinucleotide phosphate:quinine oxidoreductase 1 (NQO-1) and heme oxygenase 1 (HO-1) were also activated by Baicalin confirmed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blot. However, cotreatment with Baicalin and LY could partly abolish Baicalin-induced activation of Nrf2 and its neuroprotective effects in TBI.ConclusionThis study demonstrates that Baicalin provides a neuroprotective effect in TBI mice model via activating the Akt/Nrf2 pathway.

Lipoxin A4 inhibits UV radiation-induced skin inflammation and oxidative stress in mice

BackgroundLipoxin A4 (LXA4) is a metabolic product of arachidonic acid. Despite potent anti-inflammatory and pro-resolution activities, it remains to be determined if LXA4 has effect on ultraviolet (UV) radiation-induced skin inflammation. ObjectiveTo investigate the effects of systemic administration with LXA4 on UV radiation-induced inflammation and oxidative damage in the skin of mice. MethodsVaried parameters of inflammation and oxidative stress in the skin of mice were evaluated after UV radiation (4.14 J/cm2). ResultsPretreatment with LXA4 significantly inhibited UV radiation-induced skin edema and myeloperoxidase activity. LXA4 efficacy was enhanced by increasing the time of pre-treatment to up to 72 h. LXA4 reduced UV radiation-induced skin edema, neutrophil recruitment (myeloperoxidase activity and LysM-eGFP+ cells), MMP-9 activity, deposition of collagen fibers, epidermal thickness, sunburn cell counts, and production of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-33). Depending on the time point, LXA4 increased the levels of anti-inflammatory cytokines (TGF-β and IL-10). LXA4 significantly attenuated UV radiation-induced oxidative damage returning the oxidative status to baseline levels in parameters such as ferric reducing ability, scavenging of free radicals, GSH levels, catalase activity and superoxide anion production. LXA4 also reduced UV radiation-induced gp91phox [nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) subunit] mRNA expression and enhanced nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target enzyme nicotinamide adenine dinucleotide (phosphate) quinone oxidoreductase (Nqo1) mRNA expression. ConclusionLXA4 inhibited UV radiation-induced skin inflammation by diminishing pro-inflammatory cytokine production and oxidative stress as well as inducing anti-inflammatory cytokines and Nrf2.

Postoperative intermittent fasting prevents hippocampal oxidative stress and memory deficits in a rat model of chronic cerebral hypoperfusion.

Whether intermittent fasting (IF) treatment after stroke can prevent its long-term detrimental effects remains unknown. Here, we investigate the effects of postoperative IF on cognitive deficits and its underlying mechanisms in a permanent two-vessel occlusion (2VO) vascular dementia rat model. Rats were subjected to either IF or ad libitum feeding 1week after 2VO surgery. The cognition of rats was assessed using the novel object recognition (NOR) task and Morris water maze (MWM) 8 weeks after surgery. After behavioral testing, hippocampal malondialdehyde (MDA) and glutathione (GSH) concentrations, superoxide dismutase (SOD) activity, gene expression of antioxidative enzymes, inflammatory protein levels, and microglia density were determined. Postoperative IF significantly ameliorated the cognitive performance of 2VO rats in the NOR and MWM tests. Cognitive enhancement paralleled preservation of the PSD95 and BDNF levels in the 2VO rat hippocampus. Mechanistically, postoperative IF mitigated hippocampal oxidative stress in 2VO rats, as indicated by the reduced MDA concentration and mRNA and the protein levels of the reactive oxygen species-generating enzyme nicotinamide adenine dinucleotide phosphate oxidase 1. IF treatment also preserved the GSH level and SOD activity, as well as the levels of their upstream regulating enzymes, resulting in preserved antioxidative capability. In addition, postoperative IF prevented hippocampal microglial activation and elevation of sphingosine 1-phosphate receptor 1 and inflammatory cytokines in 2VO rats. Our results suggest that postoperative IF suppresses neuroinflammation and oxidative stress induced by chronic cerebral ischemia, thereby preserving cognitive function in a vascular dementia rat model.

Zinc and Oxidative Stress: Current Mechanisms.

Oxidative stress is a metabolic dysfunction that favors the oxidation of biomolecules, contributing to the oxidative damage of cells and tissues. This consequently contributes to the development of several chronic diseases. In particular, zinc is one of the most relevant minerals to human health, because of its antioxidant properties. This review aims to provide updated information about the mechanisms involved in the protective role of zinc against oxidative stress. Zinc acts as a co-factor for important enzymes involved in the proper functioning of the antioxidant defense system. In addition, zinc protects cells against oxidative damage, acts in the stabilization of membranes and inhibits the enzyme nicotinamide adenine dinucleotide phosphate oxidase (NADPH-Oxidase). Zinc also induces the synthesis of metallothioneins, which are proteins effective in reducing hydroxyl radicals and sequestering reactive oxygen species (ROS) produced in stressful situations, such as in type 2 diabetes, obesity and cancer. Literature provides strong evidence for the role of zinc in the protection against oxidative stress in several diseases.

Spectroscopic, quantum mechanical and molecular docking studies of a new benzoxazole compound with an oxidoreductase enzyme and DNA

The spectroscopic, theoretical molecular structure, full vibrational band assignments, MEP, NBO, frontier molecular orbitals, and NLO effects, and molecular docking studies of 5-ethylsulphonyl-2-(p-ethylphenyl)-benzoxazole, C17H17SO3N, (L) have been presented in this work. The quantum mechanical calculations have been performed by using the Hartree-Fock (HF)/6-311++G(d,p) and density functional theory (DFT) with the B3LYP/6-311++G(d,p) levels. Calculated vibrational frequencies have been compared with the experimental FT-IR spectra. The natural bond orbital (NBO) analysis has been performed to determine the hyper conjugative interactions. Frontier molecular orbitals have been defined to predict the chemical parameters of the L. The first order hyperpolarizability of L was calculated to find its role in nonlinear optics. Molecular docking of L with the oxidoreductase enzyme nicotinamide adenine dinucleotide phosphate (NADPH) exhibited the good binding affinity with energy of −8.8 kcal/mol. The molecular docking was also done to identify the interaction of L with the DNA.

Fucoxanthin Suppresses Lipid Accumulation and ROS Production During Differentiation in 3T3-L1 Adipocytes.

Fucoxanthin, a pigment from the chloroplasts of marine brown algae, has a number of effects against obesity, diabetes, inflammation and cancer and provides cerebrovascular protection. In this study, we investigated the inhibitory effects of fucoxanthin on lipid accumulation and reactive oxygen species (ROS) production during adipogenesis. Treatment with fucoxanthin suppresses protein levels of the adipogenic transcription factors CCAAT/enhancer-binding protein alpha C/EBPα and peroxisome proliferator-activated receptor-γ and of their target protein, fatty acid binding protein 4. Lipogenesis-related enzymes, such as diglyceride acyltransferase 1 and lysophosphatidic acid acyltransferase-θ, were downregulated by fucoxanthin. The ROS-producing enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) and the NADPH-generating enzyme glucose-6-phosphate dehydrogenase also decreased following fucoxanthin treatment. The adipokine adiponectin and the ROS-scavenging enzymes superoxide dismutase 2, glutathione reductase and catalase were dose-dependently increased by fucoxanthin. Furthermore, lipolysis-related enzymes and superoxide dismutase 1 were slightly decreased, because of the suppression of lipid-generating factors and the cytosolic enzyme NOX4. To confirm these results, we investigated lipid accumulation and ROS production in zebrafish, where fucoxanthin suppressed lipid and triglyceride accumulation, as well as ROS production. Our data suggest that fucoxanthin inhibits lipid accumulation and ROS production by controlling adipogenic and lipogenic factors and ROS-regulating enzymes. Copyright © 2016 John Wiley & Sons, Ltd.

Nox4 Plays a Role in TGF-β-Dependent Lens Epithelial to Mesenchymal Transition.

PurposeTransforming growth factor-β induces an epithelial to mesenchymal transition (EMT) in the lens, presented as an aberrant growth and differentiation of lens epithelial cells. Studies in other models of EMT have shown that TGF-β–driven EMT is dependent on the expression of the reactive oxygen species (ROS)–producing enzyme nicotinamide adenine dinucleotide phosphate (NADPH)–oxidase-4 (Nox4). We investigate the role of this enzyme in TGF-β–induced lens EMT and determine whether it is required for this pathologic process.MethodsRat lens epithelial explants were used to investigate the role of Nox4 in TGF-β–driven lens EMT. Nox1–4 expression and localization was determined by immunolabeling and/or RT-PCR. NADPH–oxidase–produced ROS were visualized microscopically using the fluorescent probe, dihydroethidium (DHE). VAS2870, a pan-NADPH oxidase inhibitor, was used to determine the specificity of Nox4 expression and its role in ROS production, and subsequently TGF-β–driven EMT.ResultsWe demonstrate, for the first time to our knowledge, in rat lens epithelial explants that TGF-β treatment induces Nox4 (but not Nox1–3) expression and activity. Increased Nox4 expression was first detected at 6 to 8 hours following TGF-β treatment and was maintained in explants up to 48 hours. At 8 hours after TGF-β treatment, Nox4 was observed in cell nuclei, while at later stages in the EMT process (at 48 hours), Nox4 was predominately colocalized with α-smooth muscle actin. The inhibition of Nox4 expression and activity using VAS2870 inhibited EMT progression.ConclusionsTransforming growth factor-β drives the expression of the ROS-producing enzyme Nox4 in rat lens epithelial cells and Nox4 inhibition can impede the EMT process.

Persistent activation of microglia and NADPH oxidase [corrected] drive hippocampal dysfunction in experimental multiple sclerosis.

Cognitive impairment is common in multiple sclerosis (MS). Unfortunately, the synaptic and molecular mechanisms underlying MS-associated cognitive dysfunction are largely unknown. We explored the presence and the underlying mechanism of cognitive and synaptic hippocampal dysfunction during the remission phase of experimental MS. Experiments were performed in a chronic-relapsing experimental autoimmune encephalomyelitis (EAE) model of MS, after the resolution of motor deficits. Immunohistochemistry and patch-clamp recordings were performed in the CA1 hippocampal area. The hole-board was utilized as cognitive/behavioural test. In the remission phase of experimental MS, hippocampal microglial cells showed signs of activation, CA1 hippocampal synapses presented an impaired long-term potentiation (LTP) and an alteration of spatial tests became evident. The activation of hippocampal microglia mediated synaptic and cognitive/behavioural alterations during EAE. Specifically, LTP blockade was found to be caused by the reactive oxygen species (ROS)-producing enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. We suggest that in the remission phase of experimental MS microglia remains activated, causing synaptic dysfunctions mediated by NADPH oxidase. Inhibition of microglial activation and NADPH oxidase may represent a promising strategy to prevent neuroplasticity impairment associated with active neuro-inflammation, with the aim to improve cognition and counteract MS disease progression.

Oxidative stress, NADPH oxidases, and arteries.

Atherosclerosis and its major complications - myocardial infarction and stroke - remain major causes of death and disability in the United States and world-wide. Indeed, with dramatic increases in obesity and diabetes mellitus, the prevalence and public health impact of cardiovascular diseases (CVD) will likely remain high. Major advances have been made in development of new therapies to reduce the incidence of atherosclerosis and CVD, in particular for treatment of hypercholesterolemia and hypertension. Oxidative stress is the common mechanistic link for many CVD risk factors. However, only recently have the tools existed to study the interface between oxidative stress and CVD in animal models. The most important source of reactive oxygen species (and hence oxidative stress) in vascular cells are the multiple forms of enzymes nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase). Recently published and emerging studies now clearly establish that: 1) NADPH oxidases are of critical importance in atherosclerosis and hypertension in animal models; 2) given the tissue-specific expression of key components of NADPH oxidase, it may be possible to target vascular oxidative stress for prevention of CVD.

Nrf2-ARE signals mediated the anti-oxidative action of electroacupuncture in an MPTP mouse model of Parkinson's disease

Oxidative stress and neuroinflammation are early events associated with dopaminergic neuronal degeneration in Parkinson's disease (PD). Previous studies indicated that electroacupuncture (EA) stimulation is effective in protecting dopaminergic neurons from degeneration in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. In this study, we further characterized the effect of EA on MPTP-induced oxidative responses in the mouse dopamine system. We found that subacute administration of MPTP enhanced lipid and protein oxidation and reduced expression of endogenous antioxidant enzymes (such as superoxide dismutase and catalase) in the striatum. MPTP also reduced expression of an antioxidant transcription factor, nuclear factor-E2-related factor-2 (Nrf2), and Nrf2-regulated antioxidant enzymes (nicotinamide adenine dinucleotide phosphate quinone oxidoreductase-1 and heme oxygenase-1) in the striatum and/or midbrain. Using human placental alkaline phosphatase (hPAP) as a reporter of Nrf2-regulated gene expression in hPAP transgenic mice, we found that MPTP suppressed hPAP expression in the striatum and midbrain. Application of EA at an effective frequency (100 Hz) was sufficient to reverse these changes induced by MPTP. In addition, EA reduced microglia activation and astrogliosis in the striatum and midbrain, increased tyrosine hydroxylase levels in the striatum, and improved vertical movement in MPTP mice. These results provide further evidence supporting that EA produces a series of anti-oxidative effects that effectively counteract with the oxidative stress in the nigrostriatal dopamine system induced by MPTP in a mouse model of PD.

Wear Particles Promote Reactive Oxygen Species-Mediated Inflammation via the Nicotinamide Adenine Dinucleotide Phosphate Oxidase Pathway in Macrophages Surrounding Loosened Implants

Background/Aims: Prosthesis loosening is closely associated with chronic inflammatory cytokine secretion by macrophages, which are activated by wear particles or inflammatory stimulants such as lipopolysaccharide (LPS). Reactive oxygen species (ROS) are critical regulators of inflammation, but their enzymatic sources in response to wear particles and their effects on peri-implant LPS-tolerance remain unclear. Methods: Three ROS-related enzymes—nicotinamide adenine dinucleotide phosphate oxidase (NOX)-1 and -2 and catalase—were investigated in interface membrane tissues and in titanium (Ti) particle-stimulated macrophages in vitro. The generation of ROS and downstream inflammatory effects were measured with or without pre-incubation with apocynin, an NOX inhibitor. Results: Pre-exposure to Ti particles attenuated NF-κB activation in LPS-stimulated macrophages, indicating that wear particles suppress immune response, which may lead to chronic inflammation. NOX-1 and -2 were highly expressed in aseptically loosened interface membranes and in macrophages stimulated with Ti particles; the particles induced a moderate amount of ROS generation, NF-κB activation, and TNF-a secretion in macrophages, and these effects were suppressed by apocynin. Conclusion: Wear particles induce ROS generation through the NOX signaling pathway, resulting in persistent inflammation and delayed loosening. Thus, the suppression of NOX activity may be a useful strategy for preventing prosthesis loosening.