Nox2 and Nox4 Participate in ROS-Induced Neuronal Apoptosis and Brain Injury During Ischemia-Reperfusion in Rats

MiR-367-3p Alleviates Oxidative Stress Injury in the Ischemia/Reperfusion Injury Cell Model by Targeting Nicotinamide Adenine Dinucleotide Phosphate Oxidase 4-mediated Keap1/Nrf2/ARE Pathway

ABSTRACT

Ischemic stroke is a debilitating central nervous disease linked to oxidative stress. Although miR-367-3p has been reported to be related to ischemic stroke, the direct evidence concerning oxidative stress remains elusive. Our study aimed to elucidate the mechanisms associated with oxidative stress in ischemic stroke. Initially, we discovered that miR-367-3p was notably downregulated in SH-SY5Y cells induced by oxygen-glucose deprivation/reoxygenation (OGD/R). Employing the in vitro ischemia/reperfusion injury model, we further demonstrated that overexpression of miR-367-3p alleviated OGD/R-induced apoptosis, inflammation, and oxidative stress, accompanied by the activation of the Keap1/Nrf2/ARE pathway. Mechanistically, nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) was confirmed to be the target of miR-367-3p by dual-luciferase reporter assay. Moreover, the knockdown of NOX4 mimicked, while overexpression reversed the effects of miR-367-3p overexpression on OGD/R-induced oxidative stress injury and the impaired Keap1/Nrf2/ARE pathway. In conclusion, our findings indicate that miR-367-3p mitigates OGD/R-induced oxidative stress injury by activating the Keap1/Nrf2/ARE pathway through targeting NOX4.

Activation of Hippocampal Neuronal NADPH Oxidase NOX2 Promotes Depressive-Like Behaviour and Cognition Deficits in Chronic Restraint Stress Mouse Model

BACKGROUND

Nicotinamide adenosine dinucleotide phosphate oxidases (NOX) play important roles in mediating stress-induced depression. Three NOX isotypes are expressed mainly in the brain: NOX2, NOX3 and NOX4. In this study, the expression and cellular sources of these NOX isoforms was investigated in the context of stress-induced depression.

METHODS

Chronic restraint stress (CRS)-induced depressive-like behaviour and cognitive deficits were evaluated by tail suspension tests, forced swimming tests and the Morris water maze test. Hippocampal NOX expression was determined by immunofluorescence staining and western blotting. The hippocampal levels of the brain-derived neurotrophic factor (BDNF) mRNA were determined via quantitative real-time -polymerase chain reaction. Glucocorticoid levels in the hippocampus were measured using ELISA kits.

RESULTS

In the mouse CRS model, a significant increase in NOX2 expression was observed in the hippocampus, whereas no significant changes in NOX3 and NOX4 expression were detected. Next, NOX2 expression was primarily localised to neurons (NeuN+) but not microglia (Iba-1+) or astrocytes (GFAP+). Treatment with gp91ds-tat, a specific NOX2 inhibitor, effectively mitigated the behavioural deficits induced by CRS. The decreased expression of the BDNF mRNA in the hippocampus of CRS mice was restored upon gp91ds-tat treatment. A positive correlation was identified between neuronal NOX2 expression and serum glucocorticoid levels.

CONCLUSIONS

Our study indicated that neuronal NOX2 may be a critical mediator of depression-like behaviours and spatial cognitive deficits in mice subjected to CRS. Blockade of NOX2 signalling may be a promising therapeutic strategy for depression.

Neuroprotective Effect of Benzyl Ferulate on Ischemia/Reperfusion Injury via Regulating NOX2 and NOX4 in Rats: A Potential Antioxidant for CI/R Injury

Oxidative stress is a primary contributor to cerebral ischemia/reperfusion (CI/R) injury, and the use of antioxidants represents a crucial therapeutic strategy for managing CI/R injury. This study aims to explore the antioxidant effects of benzyl ferulate on CI/R injury and elucidate its underlying mechanisms. In vivo models of CI/R injury and hypoxia/reoxygenation (H/R) injury in SH-SY5Y cells were established, followed by treatment with benzyl ferulate. The extent of oxidative stress was assessed through evaluations of neurobiological function, cerebral infarct volume, reactive oxygen species (ROS), apoptosis levels, etc. Results indicated that benzyl ferulate significantly downregulated the expression of NADPH oxidase 2 (NOX) 2/NOX4 while upregulating miRNAs (652/532/92b) in CI/R rats or SH-SY5Y cells. It also reduced total NOX enzyme activity, enhanced superoxide dismutase (SOD) activity, decreased ROS and malondialdehyde (MDA) production, and inhibited cleaved caspase-3 and Bax expression-ultimately leading to reduced cell apoptosis. Benzyl ferulate effectively mitigates oxidative stress injuries of middle cerebral artery occlusion (MCAO) rats or SH-SY5Y cells subjected to H/R, and its mechanism appears to involve modulation of the miRNAs (652/532/92b)/NOX2/4 axis. This study first proved that benzyl ferulate is a promising antioxidant candidate for treating CI/R injury.

Proteasome inhibitors induce apoptosis by superoxide anion generation via NADPH oxidase 5 in human neuroblastoma SH-SY5Y cells

The ubiquitin-proteasome system (UPS) is a major proteolytic system that plays an important role in the regulation of various cell processes, such as cell cycle, stress response, and transcriptional regulation, especially in neurons, and dysfunction of UPS is considered to be a cause of neuronal cell death in neurodegenerative diseases. However, the mechanism of neuronal cell death caused by UPS dysfunction has not yet been fully elucidated. In this study, we investigated the mechanism of neuronal cell death induced by proteasome inhibitors using human neuroblastoma SH-SY5Y cells. Z-Leu-D-Leu-Leu-al (MG132), a proteasome inhibitor, induced apoptosis in SH-SY5Y cells in a concentration- and time-dependent manner. Antioxidants N-acetylcysteine and EUK-8 attenuated MG132-induced apoptosis. Apocynin and diphenyleneiodonium, inhibitors of NADPH oxidase (NOX), an enzyme that produces superoxide anions, also attenuated MG132-induced apoptosis. It was also found that MG132 treatment increased the expression of NOX5, a NOX family member, and that siRNA-mediated silencing of NOX5 and BAPTA-AM, which inhibits NOX5 by chelating calcium, suppressed MG132-induced apoptosis and production of reactive oxygen species in SH-SY5Y cells. These results suggest that MG132 induces apoptosis in SH-SY5Y cells through the production of superoxide anion by NOX5.

The phosphokinase activity of IRE1ɑ prevents the oxidative stress injury through miR-25/Nox4 pathway after ICH

BACKGROUND

Endoplasmic reticulum (ER) stress and oxidative stress are the major pathologies encountered after intracerebral hemorrhage (ICH). Inositol-requiring enzyme-1 alpha (IRE1α) is the most evolutionarily conserved ER stress sensor, which plays a role in monitoring and responding to the accumulation of unfolded/misfolded proteins in the ER lumen. Recent studies have shown that ER stress is profoundly related to oxidative stress in physiological or pathological conditions. The purpose of this study was to investigate the role of IRE1α in oxidative stress and the potential mechanism.

METHODS

A mouse model of ICH was established by autologous blood injection. The IRE1α phosphokinase inhibitor KIRA6 was administrated intranasally at 1 h after ICH, antagomiR-25 and agomiR-25 were injected intraventricularly at 24 h before ICH. Western blot analysis, RT-qPCR, immunofluorescence staining, hematoma volume, neurobehavioral tests, dihydroethidium (DHE) staining, H2O2 content, brain water content, body weight, Hematoxylin and Eosin (HE) staining, Nissl staining, Morris Water Maze (MWM) and Elevated Plus Maze (EPM) were performed.

RESULTS

Endogenous phosphorylated IRE1α (p-IRE1α), miR-25-3p, and Nox4 were increased in the ICH model. Administration of KIRA6 downregulated miR-25-3p expression, upregulated Nox4 expression, promoted the level of oxidative stress, increased hematoma volume, exacerbated brain edema and neurological deficits, reduced body weight, aggravated spatial learning and memory deficits, and increased anxiety levels. Then antagomiR-25 further upregulated the expression of Nox4, promoted the level of oxidative stress, increased hematoma volume, exacerbated brain edema and neurological deficits, whereas agomiR-25 reversed the effects promoted by KIRA6.

CONCLUSION

The IRE1α phosphokinase activity is involved in the oxidative stress response through miR-25/Nox4 pathway in the mouse ICH brain.

The Impact of Cerebral Ischemia on Antioxidant Enzymes Activity and Neuronal Damage in the Hippocampus

Cerebral ischemia and subsequent reperfusion, leading to reduced blood supply to specific brain areas, remain significant contributors to neurological damage, disability, and mortality. Among the vulnerable regions, the subcortical areas, including the hippocampus, are particularly susceptible to ischemia-induced injuries, with the extent of damage influenced by the different stages of ischemia. Neural tissue undergoes various changes and damage due to intricate biochemical reactions involving free radicals, oxidative stress, inflammatory responses, and glutamate toxicity. The consequences of these processes can result in irreversible harm. Notably, free radicals play a pivotal role in the neuropathological mechanisms following ischemia, contributing to oxidative stress. Therefore, the function of antioxidant enzymes after ischemia becomes crucial in preventing hippocampal damage caused by oxidative stress. This study explores hippocampal neuronal damage and enzymatic antioxidant activity during ischemia and reperfusion's early and late stages.

Exosomes derived from M2-type microglia ameliorate oxygen-glucose deprivation/reoxygenation-induced HT22 cell injury by regulating miR-124-3p/NCOA4-mediated ferroptosis

Background

Although it has been reported that miRNA carried by M2 microglial exosomes protects neurons from ischemia-reperfusion brain injury, the mechanism of action remains poorly understood. This study aimed to explore the miRNA signaling pathway by which M2-type microglia-derived exosomes (M2-exosomes) ameliorate oxygen-glucose deprivation/reoxygenation (OGD/R)-induced cytotoxicity in HT22 cells.

Methods

BV2 microglia were induced by M2 polarization. Then, M2-exosomes were identified via transmission electron microscopy and special biomarker detection and co-cultured with HT22 cells. Cell proliferation was evaluated using the Cell Counting Kit-8 (CCK-8) assay. Intracellular concentrations of reactive oxygen species (ROS), Fe²⁺, glutathione (GSH), and malondialdehyde (MDA) were determined using dichlorofluorescein fluorescence and biochemical determination. miR-124-3p levels were determined using qRT-PCR, and protein expressions were examined via western blotting.

Results

OGD/R suppressed the proliferation and induced the accumulation of Fe²⁺, ROS, and MDA and reduction of GSH in mouse HT22 cells, suggesting ferroptosis of HT22 cells. OGD/R-induced changes in the above mentioned indexes was ameliorated by M2-exosomes but restored by the exosome inhibitor GW4869. M2-exosomes with (mimic-exo) or without miR-124-3p (inhibitor-exo) promoted and suppressed proliferation and ferroptosis-associated indexes of HT22 cells, respectively. Moreover, mimic-exo and inhibitor-exo inhibited and enhanced NCOA4 expression in HT22 cells, respectively. NCOA4 overexpression reversed the protective effects of miR-124-3p mimic-exo in OGD/R-conditioned cells. NCOA4 was targeted and regulated by miR-124-3p.

Conclusions

M2-exosome protects HT22 cells against OGD/R-induced ferroptosis injury by transferring miR-124-3p and NCOA4 into HT22 cells, with the latter being a target gene for miR-124-3p.

The neuroprotective and neural circuit mechanisms of acupoint stimulation for cognitive impairment

Cognitive impairment is a prevalent neurological disorder that burdens families and the healthcare system. Current conventional therapies for cognitive impairment, such as cholinesterase inhibitors and N-methyl-d-aspartate receptor antagonists, are unable to completely stop or reverse the progression of the disease. Also, these medicines may cause serious problems with the digestive system, cardiovascular system, and sleep. Clinically, stimulation of acupoints has the potential to ameliorate the common symptoms of a variety of cognitive disorders, such as memory deficit, language dysfunction, executive dysfunction, reduced ability to live independently, etc. There are common acupoint stimulation mechanisms for treating various types of cognitive impairment, but few systematic analyses of the underlying mechanisms in this domain have been performed. This study comprehensively reviewed the basic research from the last 20 years and found that acupoint stimulation can effectively improve the spatial learning and memory of animals. The common mechanism may be that acupoint stimulation protects hippocampal neurons by preventing apoptosis and scavenging toxic proteins. Additionally, acupoint stimulation has antioxidant and anti-inflammatory effects, promoting neural regeneration, regulating synaptic plasticity, and normalizing neural circuits by restoring brain functional activity and connectivity. Acupoint stimulation also inhibits the production of amyloid β-peptide and the phosphorylation of Tau protein, suggesting that it may protect neurons by promoting correct protein folding and regulating the degradation of toxic proteins via the autophagy-lysosomal pathway. However, the benefits of acupoint stimulation still need to be further explored in more high-quality studies in the future.

The Protective Effect of Vitexin Compound B-1 on Rat Cerebral I/R Injury through a Mechanism Involving Modulation of miR-92b/NOX4 Pathway

BACKGROUND

Recent studies have uncovered that vitexin compound B-1 (VB-1) can protect neurons against hypoxia/reoxygenation (H/R)-induced oxidative injury through suppressing NOX4 expression.

OBJECTIVE

The aims of this study are to investigate whether VB-1 can protect the rat brain against ischemia/ reperfusion (I/R) injury and whether its effect on NOX4 expression is related to modulation of certain miRNAs expression.

METHODS

Rats were subjected to 2 h of cerebral ischemia followed by 24 h of reperfusion to establish an I/R injury model, which showed an increase in neurological deficit score and infarct volume concomitant with an upregulation of NOX4 expression, increase in NOX activity, and downregulation of miR-92b.

RESULTS

Administration of VB-1 reduced I/R cerebral injury accompanied by a reverse in NOX4 and miR-92b expression. Similar results were achieved in a neuron H/R injury model. Next, we evaluated the association of miR-92b with NOX4 by its mimics in the H/R model. H/R treatment increased neurons apoptosis concomitant with an upregulation of NOX4 and NOX activity while downregulation of miR-92b. All these effects were reversed in the presence of miR-92b mimics, confirming the function of miR-92b in suppressing NOX4 expression.

CONCLUSION

We conclude the protective effect of VB-1 against rat cerebral I/R injury through a mechanism involving modulation of miR-92b/NOX4 pathway.

Elevated Serum NOX2 Levels Contribute to Delayed Cerebral Ischemia and a Poor Prognosis After Aneurysmal Subarachnoid Hemorrhage: A Prospective Cohort Study

Background

NADPH oxidase 2 (NOX2) is highly expressed in injured brain tissues. We determined serum NOX2 levels of aneurysmal subarachnoid hemorrhage (aSAH) patients and further investigated correlation of serum NOX2 levels with disease severity, delayed cerebral ischemia (DCI) plus prognosis after aSAH.

Methods

Serum NOX2 levels were measured in 123 aSAH patients and 123 healthy controls. World Federation of Neurological Surgeons scale (WFNS) score and modified Fisher (mFisher) score were utilized to assess disease severity. Modified Rankin scale (mRS) score was used to evaluate the clinical prognosis at 90 days after aSAH. Relations of serum NOX2 levels to DCI and 90-day poor prognosis (mRS score of 3-6) were analyzed using multivariate analysis. Receiver operating characteristic curve (ROC) was built to evaluate the prognostic predictive capability.

Results

Serum NOX2 levels in aSAH patients, compared with healthy controls, were significantly increased, and were independently correlated with WFNS score, mFisher score and post-stroke 90-day mRS score. Patients with poor prognosis or DCI had significantly higher serum NOX2 levels than other remainders, and serum NOX2 levels independently predicted 90-day poor prognosis and DCI. Serum NOX2 had high prognosis and DCI predictive abilities, and their areas under ROC curve were similar to those of WFNS score and mFisher score.

Conclusion

Serum NOX2 levels are significantly associated with hemorrhage severity, poor 90-day prognosis and DCI in aSAH patients. Hence, complement NOX2 may serve as a potential prognostic biomarker after aSAH.

Resolving Geroplasticity to the Balance of Rejuvenins and Geriatrins

According to the cell centric hypotheses, the deficits that drive aging occur within cells by age dependent progressive damage to organelles, telomeres, biologic signaling pathways, bioinformational molecules, and by exhaustion of stem cells. Here, we amend these hypotheses and propose an eco-centric model for geroplasticity (aging plasticity including aging reversal). According to this model, youth and aging are plastic and require constant maintenance, and, respectively, engage a host of endogenous rejuvenating (rejuvenins) and gero-inducing [geriatrin] factors. Aging in this model is akin to atrophy that occurs as a result of damage or withdrawal of trophic factors. Rejuvenins maintain and geriatrins adversely impact cellular homeostasis, cell fitness, and proliferation, stem cell pools, damage response and repair. Rejuvenins reduce and geriatrins increase the age-related disorders, inflammatory signaling, and senescence and adjust the epigenetic clock. When viewed through this perspective, aging can be successfully reversed by supplementation with rejuvenins and by reducing the levels of geriatrins.

Scutellarin acts on the AR-NOX axis to remediate oxidative stress injury in a mouse model of cerebral ischemia/reperfusion injury

BACKGROUND

Oxidative stress plays an important role in the pathology of ischemic stroke. Studies have confirmedthat scutellarin has antioxidant effects against ischemic injury, and we also reported that the involvement of Aldose reductase (AR) in oxidative stress and cerebral ischemic injury, in this study we furtherly explicit whether the antioxidant effect of scutellarin on cerebral ischemia injury is related to AR gene regulation and its specific mechanism.

METHODS

C57BL/6N mice (Wild-type, WT) and AR knockout (AR^-/-) mice suffered from transient middle cerebral artery occlusion (tMCAO) injury (1 h occlusion followed by 3 days reperfusion), and scutellarin was administered from 2 h before surgery to 3 days after surgery. Subsequently, neurological function was assessed by the modified Longa score method, the histopathological morphology observed with 2,3,5-triphenyltetrazolium chloride (TTC) and hematoxylin-eosin (HE) staining. Enzyme-linked immunosorbent assay (Elisa) was used to detect the levels of ROS, 4-hydroxynonenal (4-HNE), 8-hydroxydeoxyguanosine (8-OHDG), Neurotrophin-3 (NT-3), poly ADP-ribose polymerase-1 (PARP1) and 3-nitrotyrosine (3-NT) in the ischemic penumbra regions. Quantitative proteomics profiling using quantitative nano-HPLC-MS/MS were performed to compare the protein expression difference between AR^-/- and WT mice with or without tMCAO injury. The expression of AR, nicotinamide adenine dinucleotide phosphate oxidases (NOX1, NOX2 and NOX4) in the ipsilateral side of ischemic brain were detected by qRT-PCR, Western blot and immunofluorescence co-staining with NeuN.

RESULTS

Scutellarin treatment alleviated brain damage in tMCAO stroke model such as improved neurological function deficit, brain infarct area and neuronal injury and reduced the expression of oxidation-related products, moreover, also down-regulated tMCAO induced AR mRNA and protein expression. In addition, the therapeutic effect of scutellarin on the reduction of cerebral infarction area and neurological function deficits abolished in AR^-/- mice under ischemia cerebral injury, which indicated that the effect of scutellarin treatment on tMCAO injury is through regulating AR gene. Proteomic analysis of AR^-/- and WT mice indicated AR knockout would affect oxidation reaction even as NADPH related process and activity in mice under cerebral ischemia conditions. Moreover, NOX isoforms (NOX1, NOX2 and NOX4) mRNA and protein expression were significant decreased in neurons of penumbra region in AR^-/- mice compared with that in WT mice at 3d after tMCAO injury, which indicated that AR should be the upstream protein regulating NOX after cerebral ischemia.

CONCLUSIONS

We first reported that AR directly regulates NOX subtypes (not only NOX2 but also NOX1 and NOX4) after cerebral ischaemic injury. Scutellarin specifically targets the AR-NOX axis and has antioxidant effects in mice with cerebral ischaemic injury, providing a theoretical basis and accurate molecular targets for the clinical application of scutellarin.

miR-92b-3p Exerts Neuroprotective Effects on Ischemia/Reperfusion-Induced Cerebral Injury via Targeting NOX4 in a Rat Model

The necessity to increase the efficiency of organ preservation has pushed researchers to consider the mechanisms to minimize cerebral ischemia/reperfusion (I/R) injury. Hence, we evaluated the role of the miR-92b-3p/NOX4 pathway in cerebral I/R injury. A cerebral I/R injury model was established by blocking the left middle cerebral artery for 2 h and reperfusion for 24 h, and a hypoxia/reoxygenation (H/R) model was established. Thereafter, cerebral I/R increased obvious neurobiological function and brain injury (such as cerebral infarction, apoptosis, and cell morphology changes). In addition, we noted a significant decrease in the expression of miR-92b-3p, as well as increases in apoptosis and oxidative stress and an increase in NOX4. Furthermore, overexpression of miR-92b-3p blocked the inhibitory effect of miR-92b-3p on the expression of NOX4 and the accumulation of oxygen-free radicals. Bioinformatics analysis found that NOX4 may be the target gene regulated by miR-92b-3p. In conclusion, the involvement of the miR-92b-3p/NOX4 pathway ameliorated cerebral I/R injury through the prevention of apoptosis and oxidative stress. The miR-92b-3p/NOX4 pathway could be considered a potential therapeutic target to alleviate cerebral I/R injury.

ZFP36 protects against oxygen-glucose deprivation/reoxygenation-induced mitochondrial fragmentation and neuronal apoptosis through inhibiting NOX4-DRP1 pathway

The imbalance of mitochondrial dynamics plays an important role in the pathogenesis of cerebral ischemia/reperfusion (I/R) injury. Zinc-finger protein 36 (ZFP36) has been documented to have neuroprotective effects, however, whether ZFP36 is involved in the regulation of neuronal survival during cerebral I/R injury remains unknown. In this study, we found that the transcriptional and translational levels of ZFP36 were increased in immortalized hippocampal HT22 neuronal cells after oxygen-glucose deprivation/reoxygenation (OGD/R) treatment. ZFP36 gene silencing exacerbated OGD/R-induced dynamin-related protein 1 (DRP1) activity, mitochondrial fragmentation, oxidative stress and neuronal apoptosis, whereas ZFP36 overexpression exhibited the opposite effects. Besides, we found that NADPH oxidase 4 (NOX4) was upregulated by OGD/R, and NOX4 inhibition remarkably attenuated OGD/R-instigated DRP1 activity, mitochondrial fragmentation and neuronal apoptosis. Further study demonstrated that ZFP36 targeted NOX4 mRNA directly by binding to the AU-rich elements (AREs) in the NOX4 3'-untranslated regions (3'-UTR) and inhibited NOX4 expression. Taken together, our data indicate that ZFP36 protects against OGD/R-induced neuronal injury by inhibiting NOX4-mediated DRP1 activation and excessive mitochondrial fission. Pharmacological targeting of ZFP36 to suppress excessive mitochondrial fission may provide new therapeutic strategies in the treatment of cerebral I/R injury.

Foxo1-induced miR-92b down-regulation promotes blood-brain barrier damage after ischaemic stroke by targeting NOX4

The blood‐brain barrier (BBB) damage is a momentous pathological process of ischaemic stroke. NADPH oxidases 4 (NOX4) boosts BBB damage after ischaemic stroke and its expression can be influenced by microRNAs. This study aimed to probe into whether miR‐92b influenced the BBB damage after ischaemic stroke by regulating NOX4 expression. Here, miR‐92b expression was lessened in the ischaemic brains of rats and oxygen‐glucose deprivation (OGD)‐induced brain microvascular endothelial cells (BMECs). In middle cerebral artery occlusion (MCAo) rats, miR‐92b overexpression relieved the ameliorated neurological function and protected the BBB integrity. In vitro model, miR‐92b overexpression raised the viability and lessened the permeability of OGD‐induced BMECs. miR‐92b targeted NOX4 and regulated the viability and permeability of OGD‐induced BMECs by negatively modulating NOX4 expression. The transcription factor Foxo1 bound to the miR‐92b promoter and restrained its expression. Foxo1 expression was induced by OGD‐induction and its knockdown abolished the effects of OGD on miR‐92b and NOX4 expressions, cell viability and permeability of BMECs. In general, our findings expounded that Foxo1‐induced lessening miR‐92b boosted BBB damage after ischaemic stroke by raising NOX4 expression.

Increased Stress Resistance and Lifespan in Chaenorhabditis elegans Wildtype and Knockout Mutants-Implications for Depression Treatment by Medicinal Herbs

Depression and anxiety disorders are widespread diseases, and they belong to the leading causes of disability and greatest burdens on healthcare systems worldwide. It is expected that the numbers will dramatically rise during the COVID-19 pandemic. Established medications are not sufficient to adequately treat depression and are not available for everyone. Plants from traditional medicine may be promising alternatives to treat depressive symptoms. The model organism Chaenorhabditis elegans was used to assess the stress reducing effects of methanol/dichlormethane extracts from plants used in traditional medicine. After initial screening for antioxidant activity, nine extracts were selected for in vivo testing in oxidative stress, heat stress, and osmotic stress assays. Additionally, anti-aging properties were evaluated in lifespan assay. The extracts from Acanthopanax senticosus, Campsis grandiflora, Centella asiatica, Corydalis yanhusuo, Dan Zhi, Houttuynia cordata, Psoralea corylifolia, Valeriana officinalis, and Withaniasomnifera showed antioxidant activity of more than 15 Trolox equivalents per mg extract. The extracts significantly lowered ROS in mutants, increased resistance to heat stress and osmotic stress, and the extended lifespan of the nematodes. The plant extracts tested showed promising results in increasing stress resistance in the nematode model. Further analyses are needed, in order to unravel underlying mechanisms and transfer results to humans.

RNA interference targeting NOX4 protects visual function in an experimental model of retinal detachment by alleviating blood-retinal barrier damage

AIM

To observe the effects of the inhibition of NADPH oxidase 4 (NOX4) expression on the retinal vascular barriers and visual function after retinal detachment (RD).

METHODS

RD model was established 3wk after adeno-associaned virus vector injection. The retinal tissue was harvested 3d after RD, and the death of retinal vascular endothelial cells and photoreceptors was observed using electron microscopy. The NOX4 expression was detected by Western blot. Confocal microscopy was used to observe a retinal patch that had been perfused with Evans blue. A modified water maze test was used to detect the time required to find the platform on the water surface. The visual function of the rats was evaluated and reactive oxygen species (ROS) expression was detected by a fluorescence microplate reader.

RESULTS

The retinal patch showed that NOX4 interference significantly reduced the destruction of the tight junctions between the retinal endothelium of RD rats and reduced leakage. Western blotting showed decreased expression of the NOX4 protein and decreased expression of ROS in retinal tissue; the Morris water maze test results showed that NOX4 interference significantly decreased the escape latency of the rats.

CONCLUSION

NOX4 interference reduces the production of ROS in retinal vascular endothelial cells after experimental RD, thereby protecting the blood-retinal barrier and protecting visual function.

Oxymatrine Ameliorates Memory Impairment in Diabetic Rats by Regulating Oxidative Stress and Apoptosis: Involvement of NOX2/NOX4

Oxymatrine (OMT) is the major quinolizidine alkaloid extracted from the root of Sophora flavescens Ait and has been shown to exhibit a diverse range of pharmacological properties. The aim of the present study was to investigate the role of OMT in diabetic brain injury in vivo and in vitro. Diabetic rats were induced by intraperitoneal injection of a single dose of 65 mg/kg streptozotocin (STZ) and fed a high-fat and high-cholesterol diet. Memory function was assessed using a Morris water maze test. A SH-SY5Y cell injury model was induced by incubation with glucose (30 mM/l) to simulate damage in vitro. The serum fasting blood glucose, insulin, serum S100B, malondialdehyde (MDA), and superoxide dismutase (SOD) levels were analyzed using commercial kits. Morphological changes were observed using Nissl staining and electron microscopy. Cell apoptosis was assessed using Hoechst staining and TUNEL staining. NADPH oxidase (NOX) and caspase-3 activities were determined. The effects of NOX2 and NOX4 knockdown were assessed using small interfering RNA. The expression levels of NOX1, NOX2, and NOX4 were detected using reverse transcription-quantitative PCR and western blotting, and the levels of caspase-3 were detected using western blotting. The diabetic rats exhibited significantly increased plasma glucose, insulin, reactive oxygen species (ROS), S-100B, and MDA levels and decreased SOD levels. Memory function was determined by assessing the percentage of time spent in the target quadrant, the number of times the platform was crossed, escape latency, and mean path length and was found to be significantly reduced in the diabetic rats. Hyperglycemia resulted in notable brain injury, including histological changes and apoptosis in the cortex and hippocampus. The expression levels of NOX2 and NOX4 were significantly upregulated at the protein and mRNA levels, and NOX1 expression was not altered in the diabetic rats. NOX and caspase-3 activities were increased, and caspase-3 expression was upregulated in the brain tissue of diabetic rats. OMT treatment dose-dependently reversed behavioral, biochemical, and molecular changes in the diabetic rats. In vitro, high glucose resulted in increases in reactive oxygen species (ROS), MDA levels, apoptosis, and the expressions of NOX2, NOX4, and caspase-3. siRNA-mediated knockdown of NOX2 and NOX4 decreased NOX2 and NOX4 expression levels, respectively, and reduced ROS levels and apoptosis. The results of the present study suggest that OMT alleviates diabetes-associated cognitive decline, oxidative stress, and apoptosis via NOX2 and NOX4 inhibition.

Down-Regulation of NOX4 Expression in Dorsal Horn of Spinal Cord Could Alleviate Cancer-Induced Bone Pain in Rats by Reducing Oxidative Stress Response

Introduction

Cancer-induced bone pain (CIBP) is very common in patients with advanced cancer. Recent studies have shown that reactive oxygen species (ROS) can sense and regulate pain response process through spinal cord mechanism, and play a role in CIBP. NADPH oxidase (NOX) is a group of protease complexes that produce ROS. In the current study, we investigated the expression of NOX4 in the spinal dorsal horn of rats with CIBP and its related role and molecular mechanism.

Materials and Methods

A rat CIBP model was established by injecting Walker-256 cells into the tibia medullary cavity, and the expression of NOX4 in spinal dorsal horn was down-regulated by injecting lentivirus into spinal cord. RT-PCR, Western blot and immunofluorescence staining were used to detect the expression of NOX4 in CIBP rats, cell localization and its effect on CIBP rats, and the effect of down-regulating the expression of NOX4 on the expression of H₂O₂, nitric oxide synthase nNO, antioxidant enzyme SOD, and the activity of neuro-receptor in spinal dorsal horn of rats.

Results

In rats with CIBP, the expression of NOX4 was significantly increased, and immunofluorescence showed that NOX4 was mainly expressed in microglia in the dorsal horn of spinal cord. Down-regulating the expression of NOX4 in rats can reduce the level of H₂O₂ and nNO in dorsal horn tissue, and increase the expression of SOD to reduce the oxidative stress response. At the same time, down-regulating NOX4 can reduce the sensitivity of spinal cord and relieve the pain of bone cancer by inhibiting the expression of NMDAR and GABAA-γ2 in dorsal horn tissue.

Conclusion

NOX4 is a promising therapeutic target in CIBP, and down-regulation of NOX4 expression can alleviate CIBP in rats by reducing oxidative stress and weakening spinal cord sensitization.

Redox signalling and regulation of the blood-brain barrier

Neurological disorders are associated with increased oxidative stress. Reactive oxidants damage tissue and promote cell death, but it is apparent that oxidants can have more subtle effects on cell function through the modulation of redox-sensitive signalling pathways. Cells of the blood-brain barrier regulate the brain microenvironment but become dysfunctional during neurological disease. The blood-brain barrier is maintained by many cell types, and is modulated by redox-sensitive pathways, ranging from the cytoskeletal elements responsible for establishing a barrier, to growth factor and cytokine signalling pathways that influence neurovascular cells. During neurological disease, blood-brain barrier cells are exposed to exogenously generated oxidants from immune cells, as well as increasing endogenously oxidant production. These oxidants impair the function of the blood-brain barrier, leading to increased leakage and reduced blood flow. Reducing the impact of oxidants on the function of blood-brain barrier cells may provide new strategies for delaying the progression of neurological disease.