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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. [ABSTRACT FROM AUTHOR]

Acute myeloid leukaemia (AML) is a highly heterogeneous malignancy, with a poor 5-year overall survival rate of approximately 30%. Consequently, the search for novel therapeutic strategies is ongoing, and the identification of new vulnerabilities could accelerate progress. Oxidative stress and metabolic rewiring are established hallmarks of cancer, and recent evidence suggests that NADPH oxidases may regulate metabolism, potentially linking these two processes. Increasing research highlights the importance of NOX2 in AML, particularly its role in metabolic regulation. In this study, we investigated the effects of simultaneously inhibiting NOX2 and glycolysis in AML cells. Dual inhibition of NOX2 and glycolysis—by targeting hexokinase or lactate dehydrogenase (LDH)—significantly reduced cell proliferation, markedly impaired clonogenic potential, and induced extensive cell death in a broad panel of AML cell lines. Importantly, these findings were further validated in primary bone marrow samples derived from AML patients, where combined inhibition triggered similar potent anti-leukemic effects. Furthermore, the combined inhibition of NOX2 and LDH enhanced the efficacy of cytarabine (AraC), suggesting this approach could boost the effectiveness of conventional therapies. In an in vivo AML model, targeting NOX2 and LDH in myeloid progenitor cells delayed the onset of leukaemia and extended survival. In conclusion, our findings propose a novel therapeutic strategy for AML through the dual targeting of NOX2 and glycolysis. [ABSTRACT FROM AUTHOR]

Advanced glycation end products (AGEs) are risk factors for various diseases, including sarcopenia. One of the deleterious effects of AGEs is the induction of abnormal reactive oxygen species (ROS) production in skeletal muscle. However, the underlying mechanism remains poorly understood. Therefore, the aim of this study was to elucidate how AGEs induce ROS production in skeletal muscle cells. This study demonstrated that AGEs treatment promoted ROS production in myoblasts and myotubes while PKC inhibitor abolished ROS production by AGEs stimulation. Phosphorylation of p47 phox by kinases such as PKCα is required to form the Nox2 complex, which induces ROS production. In this study, AGEs treatment promoted the phosphorylation of PKCα and p47 phox in myoblasts and myotubes. Our findings suggest that AGEs promote ROS production through the phosphorylation of PKCα and p47 phox in skeletal muscle cells. [ABSTRACT FROM AUTHOR]

Myocardial stretch physiologically activates NADPH oxidase 2 (NOX2) to increase reactive oxygen species (ROS) production. Although physiological low‐level ROS are known to be important as signalling molecules, the role of stretch‐induced ROS in the intact myocardium remains unclear. To address this, we investigated the effects of stretch‐induced ROS on myocardial cellular contractility and calcium transients in C57BL/6J and NOX2−/− mice. Axial stretch was applied to the isolated cardiomyocytes using a pair of carbon fibres attached to both cell ends to evaluate stretch‐induced modulation in the time course of the contraction curve and calcium transient, as well as to evaluate maximum cellular elastance, an index of cellular contractility, which is obtained from the end‐systolic force–length relationship. In NOX2−/− mice, the peak calcium transient was not altered by stretch, as that in wild‐type mice, but the lack of stretch‐induced ROS delayed the rise of calcium transients and reduced contractility. Our mathematical modelling studies suggest that the augmented activation of ryanodine receptors by stretch‐induced ROS causes a rapid and large increase in the calcium release flux, resulting in a faster rise in the calcium transient. The slight increase in the magnitude of calcium transients is offset by a decrease in sarcoplasmic reticulum calcium content as a result of ROS‐induced calcium leakage, but the faster rise in calcium transients still maintains higher contractility. In conclusion, a physiological role of stretch‐induced ROS is to increase contractility to counteract a given preload, that is, it contributes to the Frank–Starling law of the heart. Key points: Myocardial stretch increases the production of reactive oxygen species by NADPH oxidase 2.We used NADPH oxidase 2 knockout mice to elucidate the physiological role of stretch‐induced reactive oxygen species in the heart.We showed that stretch‐induced reactive oxygen species modulate the rising phase of calcium transients and increase myocardial contractility.A mathematical model simulation study demonstrated that rapid activation of ryanodine receptors by reactive oxygen species is important for increased contractility.This response is advantageous for the myocardium, which must contract against a given preload. [ABSTRACT FROM AUTHOR]

M2-polarized, tumor-associated macrophages (TAMs) produce pro-tumorigenic and angiogenic mediators, such as interleukin-8 (IL-8) and IL-10. Leucine-rich repeat-containing protein 8 members (LRRC8s) form volume-regulated anion channels and play an important role in macrophage functions by regulating cytokine and chemokine production. We herein examined the role of LRRC8A in IL-8 and IL-10 expression in THP-1-differentiated M2-like macrophages (M2-MACs), which are a useful tool for investigating TAMs. In M2-MACs, the pharmacological inhibition of LRRC8A led to hyperpolarizing responses after a transient depolarization phase, followed by a slight elevation in the intracellular concentration of Ca2+. Both the small interfering RNA-mediated and pharmacological inhibition of LRRC8A repressed the transcriptional expression of IL-8 and IL-10, resulting in a significant reduction in their secretion. The inhibition of LRRC8A decreased the nuclear translocation of phosphorylated nuclear factor-erythroid 2-related factor 2 (Nrf2), while the activation of Nrf2 reversed the LRRC8A inhibition-induced transcriptional repression of IL-8 and IL-10 in M2-MACs. We identified the CCAAT/enhancer-binding protein isoform B, CEBPB, as a downstream target of Nrf2 signaling in M2-MACs. Moreover, among several upstream candidates, the inhibition of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) suppressed the Nrf2–CEBPB transcriptional axis in M2-MACs. Collectively, the present results indicate that the inhibition of LRRC8A repressed IL-8 and IL-10 transcription in M2-MACs through the NOX2–Nrf2–CEBPB axis and suggest that LRRC8A inhibitors suppress the IL-10-mediated evasion of tumor immune surveillance and IL-8-mediated metastasis and neovascularization in TAMs. [ABSTRACT FROM AUTHOR]

Neutrophil extracellular traps (NETs) are three-dimensional reticular structures that release chromatin and cellular contents extracellularly upon neutrophil activation. As a novel effector mechanism of neutrophils, NETs possess the capacity to amplify localized inflammation and have been demonstrated to contribute to the exacerbation of various inflammatory diseases, including cardiovascular diseases and tumors. It is suggested that lysophosphatidylcholine (LPC), as the primary active component of oxidized low-density lipoprotein, represents a significant risk factor for various inflammatory diseases, such as cardiovascular diseases and neurodegenerative diseases. However, the specific mechanism of NETs formation induced by LPC remains unclear. Quercetin has garnered considerable attention due to its anti-inflammatory properties, serving as a prevalent flavonoid in daily diet. However, little is currently known about the underlying mechanisms by which quercetin inhibits NETs formation and alleviates associated diseases. In our study, we utilized LPC-treated primary rat neutrophils to establish an in vitro model of NETs formation, which was subsequently subjected to treatment with a combination of quercetin or relevant inhibitors/activators. Compared to the control group, the markers of NETs and the expression of P2X7R/P38MAPK/NOX2 pathway-associated proteins were significantly increased in cells treated with LPC alone. Quercetin intervention decreased the LPC-induced upregulation of the P2X7R/P38MAPK/NOX2 pathway and effectively reduced the expression of NETs markers. The results obtained using a P2X7R antagonist/activator and P38MAPK inhibitor/activator support these findings. In summary, quercetin reversed the upregulation of the LPC-induced P2X7R/P38MAPK/NOX2 pathway, further mitigating NETs formation. Our study investigated the potential mechanism of LPC-induced NETs formation, elucidated the inhibitory effect of quercetin on NETs formation, and offered new insights into the anti-inflammatory properties of quercetin. [ABSTRACT FROM AUTHOR]

Energy status is linked to the production of reactive oxygen species (ROS) in macrophages, which is elevated in obesity. However, it is unclear how ROS production is upregulated in macrophages in response to energy overload for mediating the development of obesity. Here, we show that the Rab-GTPase activating protein (RabGAP) TBC1D1, a substrate of the energy sensor AMP-activated protein kinase (AMPK), is a critical regulator of macrophage ROS production and consequent adipose inflammation for obesity development. TBC1D1 deletion decreases, whereas an energy overload-mimetic non-phosphorylatable TBC1D1S231A mutation increases, ROS production and M1-like polarization in macrophages. Mechanistically, TBC1D1 and its downstream target Rab8a form an energy-responsive complex with NOX2 for ROS generation. Transplantation of TBC1D1S231A bone marrow aggravates diet-induced obesity whereas treatment with an ultra-stable TtSOD for removal of ROS selectively in macrophages alleviates both TBC1D1S231A mutation- and diet-induced obesity. Our findings therefore have implications for drug discovery to combat obesity. [ABSTRACT FROM AUTHOR]

Abstract Acute myeloid leukaemia (AML) is a highly heterogeneous malignancy, with a poor 5-year overall survival rate of approximately 30%. Consequently, the search for novel therapeutic strategies is ongoing, and the identification of new vulnerabilities could accelerate progress. Oxidative stress and metabolic rewiring are established hallmarks of cancer, and recent evidence suggests that NADPH oxidases may regulate metabolism, potentially linking these two processes. Increasing research highlights the importance of NOX2 in AML, particularly its role in metabolic regulation. In this study, we investigated the effects of simultaneously inhibiting NOX2 and glycolysis in AML cells. Dual inhibition of NOX2 and glycolysis—by targeting hexokinase or lactate dehydrogenase (LDH)—significantly reduced cell proliferation, markedly impaired clonogenic potential, and induced extensive cell death in a broad panel of AML cell lines. Importantly, these findings were further validated in primary bone marrow samples derived from AML patients, where combined inhibition triggered similar potent anti-leukemic effects. Furthermore, the combined inhibition of NOX2 and LDH enhanced the efficacy of cytarabine (AraC), suggesting this approach could boost the effectiveness of conventional therapies. In an in vivo AML model, targeting NOX2 and LDH in myeloid progenitor cells delayed the onset of leukaemia and extended survival. In conclusion, our findings propose a novel therapeutic strategy for AML through the dual targeting of NOX2 and glycolysis.

Abstract Background Extracellular matrix (ECM) stiffness is closely related to the progress of diabetic cardiomyopathy (DCM) and the response of treatment of DCM to anti-diabetic drugs. Dapagliflozin (Dapa) has been proven to have cardio-protective efficacy for diabetes and listed as the first-line drug to treat heart failure. But the regulatory relationship between ECM stiffness and treatment efficacy of Dapa remains elusive. Materials and methods This work investigated the effect of ECM stiffness on DCM progression and Dapa efficacy using both in vivo DCM rat model and in vitro myocardial cell model with high glucose injury. First, through DCM rat models with various levels of myocardial injury and administration with Dapa treatment for four weeks, the levels of myocardial injury, myocardial oxidative stress, expressions of AT1R (a mechanical signal protein) and the stiffness of myocardial tissues were obtained. Then for mimicking the stiffness of myocardial tissues at early and late stages of DCM, we constructed cell models through culturing H9c2 myocardial cells on the polyacrylamide gels with two stiffness and exposed to a high glucose level and without/with Dapa intervention. The cell viability, reactive oxygen species (ROS) levels and expressions of mechanical signal sensitive proteins were obtained. Results The DCM progression is accompanied by the increased myocardial tissue stiffness, which can synergistically exacerbate myocardial cell injury with high glucose. Dapa can improve the ECM stiffness-induced DCM progression and its efficacy on DCM is more pronounced on the soft ECM, which is related to the regulation pathway of AT1R-FAK-NOX2. Besides, Dapa can inhibit the expression of the ECM-induced integrin β1, but without significant impact on piezo 1. Conclusions Our study found the regulation and effect of biomechanics in the DCM progression and on the Dapa efficacy on DCM, providing the new insights for the DCM treatment. Additionally, our work showed the better clinical prognosis of DCM under early Dapa intervention.

Sepsis is a systemic inflammatory response syndrome caused by the invasion of pathogenic microorganisms. Despite major advances in diagnosis and technology, morbidity and mortality remain high. The level of neutrophil extracellular traps (NETs) is closely associated with the progression and prognosis of sepsis, suggesting the regulation of NET formation as a new strategy in sepsis treatment. Owing to its pleiotropic effects, atorvastatin, a clinical lipid-lowering drug, affects various aspects of sepsis-related inflammation and immune responses. To align closely with clinical practice, we combined it with imipenem for the treatment of sepsis. In this study, we used a cecum ligation and puncture-induced lung injury mouse model and employed techniques including western blot, immunofluorescence, and enzyme-linked immunosorbent assay to measure the levels of NETs and other sepsis-related lung injury indicators. Our findings indicate that atorvastatin effectively inhibited the formation of NETs. When combined with imipenem, it significantly alleviated lung injury, reduced systemic inflammation, and improved the 7-day survival rate of septic mice. Additionally, we explored the inhibitory mechanism of atorvastatin on NET formation in vitro , revealing its potential action through the ERK/NOX2 pathway. Therefore, atorvastatin is a potential immunomodulatory agent that may offer new treatment strategies for patients with sepsis in clinical settings. [Display omitted] • Atorvastatin regulates the formation of neutrophil extracellular traps (NETs). • Atorvastatin inhibits NETs through the ERK/NOX2 signaling pathway. • Atorvastatin combined with imipenem alleviates sepsis-induced lung injury by inhibiting NETs. [ABSTRACT FROM AUTHOR]

Background: Extracellular matrix (ECM) stiffness is closely related to the progress of diabetic cardiomyopathy (DCM) and the response of treatment of DCM to anti-diabetic drugs. Dapagliflozin (Dapa) has been proven to have cardio-protective efficacy for diabetes and listed as the first-line drug to treat heart failure. But the regulatory relationship between ECM stiffness and treatment efficacy of Dapa remains elusive. Materials and methods: This work investigated the effect of ECM stiffness on DCM progression and Dapa efficacy using both in vivo DCM rat model and in vitro myocardial cell model with high glucose injury. First, through DCM rat models with various levels of myocardial injury and administration with Dapa treatment for four weeks, the levels of myocardial injury, myocardial oxidative stress, expressions of AT1R (a mechanical signal protein) and the stiffness of myocardial tissues were obtained. Then for mimicking the stiffness of myocardial tissues at early and late stages of DCM, we constructed cell models through culturing H9c2 myocardial cells on the polyacrylamide gels with two stiffness and exposed to a high glucose level and without/with Dapa intervention. The cell viability, reactive oxygen species (ROS) levels and expressions of mechanical signal sensitive proteins were obtained. Results: The DCM progression is accompanied by the increased myocardial tissue stiffness, which can synergistically exacerbate myocardial cell injury with high glucose. Dapa can improve the ECM stiffness-induced DCM progression and its efficacy on DCM is more pronounced on the soft ECM, which is related to the regulation pathway of AT1R-FAK-NOX2. Besides, Dapa can inhibit the expression of the ECM-induced integrin β1, but without significant impact on piezo 1. Conclusions: Our study found the regulation and effect of biomechanics in the DCM progression and on the Dapa efficacy on DCM, providing the new insights for the DCM treatment. Additionally, our work showed the better clinical prognosis of DCM under early Dapa intervention. [ABSTRACT FROM AUTHOR]

Essential for reactive oxygen species (EROS) protein is a recently identified molecular chaperone of NOX2 (gp91phox), the catalytic subunit of phagocyte NADPH oxidase. Deficiency in EROS is a recently identified cause for chronic granulomatous disease, a genetic disorder with recurrent bacterial and fungal infections. Here, we report a cryo-EM structure of the EROS-NOX2-p22phox heterotrimeric complex at an overall resolution of 3.56Å. EROS and p22phox are situated on the opposite sides of NOX2, and there is no direct contact between them. EROS associates with NOX2 through two antiparallel transmembrane (TM) α-helices and multiple β-strands that form hydrogen bonds with the cytoplasmic domain of NOX2. EROS binding induces a 79° upward bend of TM2 and a 48° backward rotation of the lower part of TM6 in NOX2, resulting in an increase in the distance between the two hemes and a shift of the binding site for flavin adenine dinucleotide (FAD). These conformational changes are expected to compromise superoxide production by NOX2, suggesting that the EROS-bound NOX2 is in a protected state against activation. Phorbol myristate acetate, an activator of NOX2 in vitro, is able to induce dissociation of NOX2 from EROS with concurrent increase in FAD binding and superoxide production in a transfected COS-7 model. In differentiated neutrophil-like HL-60, the majority of NOX2 on the cell surface is dissociated with EROS. Further studies are required to delineate how EROS dissociates from NOX2 during its transport to cell surface, which may be a potential mechanism for regulation of NOX2 activation. [ABSTRACT FROM AUTHOR]

Reactive oxygen species are important effectors and modifiers of the acute inflammatory response, recruiting phagocytes including neutrophils to sites of tissue injury. In turn, phagocytes such as neutrophils are both consumers and producers of reactive oxygen species. Phagocytes including neutrophils generate reactive oxygen species in an oxidative burst through the activity of a multimeric phagocytic nicotinamide adenine dinucleotide phosphate oxidase complex. Mutations in the NOX2/CYBB (previously gp91phox) nicotinamide adenine dinucleotide phosphate oxidase subunit are the commonest cause of chronic granulomatous disease, a disease characterized by infection susceptibility and an inflammatory phenotype. To model chronic granulomatous disease, we made a nox2/cybb zebrafish (Danio rerio) mutant and demonstrated it to have severely impaired myeloid cell reactive oxygen species production. Reduced early survival of nox2 mutant embryos indicated an essential requirement for nox2 during early development. In nox2/cybb zebrafish mutants, the dynamics of initial neutrophil recruitment to both mild and severe surgical tailfin wounds was normal, suggesting that excessive neutrophil recruitment at the initiation of inflammation is not the primary cause of the "sterile" inflammatory phenotype of chronic granulomatous disease patients. This nox2 zebrafish mutant adds to existing in vivo models for studying reactive oxygen species function in myeloid cells including neutrophils in development and disease. [ABSTRACT FROM AUTHOR]

Salmonella invades host cells and replicates inside acidified, remodeled vacuoles that are exposed to reactive oxygen species (ROS) generated by the innate immune response. Oxidative products of the phagocyte NADPH oxidase mediate antimicrobial activity, in part, by collapsing the ΔpH of intracellular Salmonella. Given the role of arginine in bacterial resistance to acidic pH, we screened a library of 54 single-gene mutants in Salmonella that are each involved in, but do not entirely block, arginine metabolism. We identified several mutants that affected Salmonella virulence in mice. The triple mutant ΔargCBH, which is deficient in arginine biosynthesis, was attenuated in immunocompetent mice, but recovered virulence in phagocyte NADPH oxidase deficient Cybb-/- mice. Furthermore, ΔargCBH Salmonella was profoundly susceptible to the bacteriostatic and bactericidal effects of hydrogen peroxide. Peroxide stress led to a larger collapse of the ΔpH in ΔargCBH mutants than occurred in wild-type Salmonella. The addition of exogenous arginine rescued ΔargCBH Salmonella from peroxide-induced ΔpH collapse and killing. Combined, these observations suggest that arginine metabolism is a hitherto unknown determinant of virulence that contributes to the antioxidant defenses of Salmonella by preserving pH homeostasis. In the absence of phagocyte NADPH oxidase-produced ROS, host cell-derived l-arginine appears to satisfy the needs of intracellular Salmonella. However, under oxidative stress, Salmonella must additionally rely on de novo biosynthesis to maintain full virulence.

Extracellular vesicles (EVs) are a type of cytoplasmic vesicles secreted by a variety of cells. EVs originating from cells have been known to participate in cell communication, antigen presentation, immune cell activation, tolerance induction, etc. These EVs can also carry the active form of Nicotinamide Adenine Dinucleotide Phosphate Oxidase Hydrogen (NADPH) oxidase, which is very essential for the production of reactive oxygen species (ROS) and that can then modulate processes such as cell regeneration. The aim of this study is to characterize the EVs isolated from U-937 and THP-1 cells, identify the NADPH oxidase (NOX) isoforms, and to determine whether EVs can modulate NOX4 and NOX2 in monocytes and macrophages. In our study, isolated EVs of U-937 were characterized using dynamic light scattering (DLS) spectroscopy and immunoblotting. The results showed that the exogenous addition of differentiation agents (either phorbol 12-myristate 13-acetate (PMA) or ascorbic acid) or the supplementation of EVs used in the study did not cause any stress leading to alterations in cell proliferation and viability. In cells cocultured with EVs for 72 h, strong suppression of NOX4 and NOX2 is evident when monocytes transform into macrophagic cells. We also observed lower levels of oxidative stress measured using immunoblotting and electron paramagnetic resonance spectroscopy under the EVs co-cultured condition, which also indicates that EVs might contribute significantly by acting as an antioxidant source, which agrees with previous studies that hypothesized the role of EVs in therapeutics. Therefore, our results provide evidence for NOX regulation by EVs in addition to its role as an antioxidant cargo. [ABSTRACT FROM AUTHOR]

Background: NADPH oxidase 2 (NOX2) is an important source of reactive oxygen species (ROS). Activated NOX2 may contribute to Alzheimer's disease (AD). Our previous studies showed that a novel vitamin E mixture, Tocovid, had potential neuroprotective effects in a stroke mice model and an AD cell model. Objective: The aim of this study was two-fold: to assess whether long-term Tocovid treatment can regulate NOX2, and the therapeutic effects of long-term administration of Tocovid to an AD mice model. Methods: Therapeutic effects of long-term administration of Tocovid (200 mg/kg /day) on an Aβ-overexpressed transgenic AD mice model (APP23, n = 8) was investigated. The therapeutic effect of Tocovid in 16-month-old mice compared with the no-treatment APP23 group (n = 9) was assessed. Results: Tocovid treatment strongly improved motor and memory deficits of APP23 mice by attenuating NOX2 expression, oxidative stress, neuroinflammation, neurovascular unit dysfunction, synaptic alteration, and Aβ deposition after 16 months. Conclusion: These findings suggest that NOX2 is a potential target in AD pathology. Long-term administration of Tocovid may be a promising candidate for AD treatment. [ABSTRACT FROM AUTHOR]

A cell's most significant existential task is to survive by ensuring proper metabolism, avoiding harmful stimuli, and adapting to changing environments. It explains why early evolutionary primordial signals and pathways remained active and regulate cell and tissue integrity. This requires energy supply and a balanced redox state. To meet these requirements, the universal intracellular energy transporter purine nucleotide-adenosine triphosphate (ATP) became an important signaling molecule and precursor of purinergic signaling after being released into extracellular space. Similarly, ancient proteins involved in intracellular metabolism gave rise to the third protein component (C3) of the complement cascade (ComC), a soluble arm of innate immunity. These pathways induce cytosol reactive oxygen (ROS) and reactive nitrogen species (RNS) that regulate the redox state of the cells. While low levels of ROS and RNS promote cell growth and differentiation, supra-physiological concentrations can lead to cell damage by pyroptosis. This balance explains the impact of purinergic signaling and innate immunity on cell metabolism, organogenesis, and tissue development. Subsequently, along with evolution, new regulatory cues emerge in the form of growth factors, cytokines, chemokines, and bioactive lipids. However, their expression is still modulated by both primordial signaling pathways. This review will focus on the data that purinergic signaling and innate immunity carry on their ancient developmental task in hematopoiesis and specification of hematopoietic stem/progenitor cells (HSPCs). Moreover, recent evidence shows both these regulatory pathways operate in a paracrine manner and inside HSPCs at the autocrine level. [ABSTRACT FROM AUTHOR]

Cerebral malaria (CM), a severe neurological pathology caused by Plasmodium falciparum infection, poses a significant global health threat and has a high mortality rate. Conventional therapeutics cannot cross the blood–brain barrier (BBB) efficiently. Therefore, finding effective treatments remains challenging. The novelty of the treatment proposed in this study lies in the feasibility of intranasal (IN) delivery of the nanostructured lipid carrier system (NLC) combining microRNA (miRNA) and artemether (ARM) to enhance bioavailability and brain targeting. The rational use of NLCs and RNA-targeted therapeutics could revolutionize the treatment strategies for CM management. This study can potentially address the challenges in treating CM, allowing drugs to pass through the BBB. The NLC formulation was developed by a hot-melt homogenization process utilizing 3% (w/w) precirol and 1.5% (w/v) labrasol, resulting in particles with a size of 94.39 nm. This indicates an effective delivery to the brain via IN administration. The results further suggest the effective intracellular delivery of encapsulated miRNAs in the NLCs. Investigations with an experimental cerebral malaria mouse model showed a reduction in parasitaemia, preservation of BBB integrity, and reduced cerebral haemorrhages with the ARM+ miRNA-NLC treatment. Additionally, molecular discoveries revealed that nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) and Interleukin-6 (IL-6) levels were reduced in the treated groups in comparison to the CM group. These results support the use of nanocarriers for IN administration, offering a viable method for mitigating CM through the increased bioavailability of therapeutics. Our findings have far-reaching implications for future research and personalized therapy. [ABSTRACT FROM AUTHOR]

Acute lung injury (ALI) and its severe manifestation, acute respiratory distress syndrome (ARDS), are characterized by uncontrolled inflammatory responses, neutrophil activation and infiltration, damage to the alveolar capillary membrane, and diffuse alveolar injury. Neutrophil extracellular traps (NETs), formed by activated neutrophils, contribute significantly to various inflammatory disorders and can lead to tissue damage and organ dysfunction. Corilagin, a compound found in Phyllanthus urinaria, possesses antioxidative and anti-inflammatory properties. In this study, we investigated the protective effects and underlying mechanisms of corilagin in hydrochloric acid (HCl)/lipopolysaccharide (LPS)-induced lung injury. Mice received intraperitoneal administration of corilagin (2.5, 5, or 10 mg/kg) or an equal volume of saline 30 min after intratracheal HCl/LPS administration. After 20 h, lung tissues were collected for analysis. Corilagin treatment significantly mitigated lung injury, as evidenced by reduced inflammatory cell infiltration, decreased production of proinflammatory cytokines, and alleviated oxidative stress. Furthermore, corilagin treatment suppressed neutrophil elastase expression, reduced NET formation, and inhibited the expression of ERK, p38, AKT, STAT3, and NOX2. Our findings suggest that corilagin inhibits NET formation and protects against HCl/LPS-induced ALI in mice by modulating the STAT3 and NOX2 signaling pathways. [ABSTRACT FROM AUTHOR]

The chaperone protein EROS (“Essential for Reactive Oxygen Species”) was recently discovered in phagocytes. EROS was shown to regulate the abundance of the ROS-producing enzyme NADPH oxidase isoform 2 (NOX2) and to control ROS-mediated cell killing. Reactive oxygen species are important not only in immune surveillance, but also modulate physiological signaling responses in multiple tissues. The roles of EROS have not been previously explored in the context of oxidant-modulated cell signaling. Here we show that EROS plays a key role in ROS-dependent signal transduction in vascular endothelial cells. We used siRNA-mediated knockdown and developed CRISPR/Cas9 knockout of EROS in human umbilical vein endothelial cells (HUVEC), both of which cause a significant decrease in the abundance of NOX2 protein, associated with a marked decrease in RAC1, a small G protein that activates NOX2. Loss of EROS also attenuates receptor-mediated hydrogen peroxide (H2O2) and Ca2+ signaling, disrupts cytoskeleton organization, decreases cell migration, and promotes cellular senescence. EROS knockdown blocks agonist-modulated eNOS phosphorylation and nitric oxide (NO●) generation. These effects of EROS knockdown are strikingly similar to the alterations in endothelial cell responses that we previously observed following RAC1 knockdown. Proteomic analyses following EROS or RAC1 knockdown in endothelial cells showed that reduced abundance of these two distinct proteins led to largely overlapping effects on endothelial biological processes, including oxidoreductase, protein phosphorylation, and endothelial nitric oxide synthase (eNOS) pathways. These studies demonstrate that EROS plays a central role in oxidant-modulated endothelial cell signaling by modulating NOX2 and RAC1.

Background & aimsThe stimulator of interferon genes (STING)/TANK-binding kinase 1 (TBK1) pathway is vital in mediating innate immune and inflammatory responses during oxidative/endoplasmic reticulum (ER) stress. However, it remains unknown whether macrophage thioredoxin-interacting protein (TXNIP) may regulate TBK1 function and cell death pathways during oxidative/ER stress.MethodsA mouse model of hepatic ischaemia/reperfusion injury (IRI), the primary hepatocytes, and bone marrow-derived macrophages were used in the myeloid-specific TXNIP knockout (TXNIPM-KO) and TXNIP-proficient (TXNIPFL/FL) mice.ResultsThe TXNIPM-KO mice were resistant to ischaemia/reperfusion (IR) stress-induced liver damage with reduced serum alanine aminotransferase (ALT)/aspartate aminotransferase (AST) levels, macrophage/neutrophil infiltration, and pro-inflammatory mediators compared with the TXNIPFL/FL controls. IR stress increased TXNIP, p-STING, and p-TBK1 expression in ischaemic livers. However, TXNIPM-KO inhibited STING, TBK1, interferon regulatory factor 3 (IRF3), and NF-κB activation with interferon-β (IFN-β) expression. Interestingly, TXNIPM-KO augmented nuclear factor (erythroid-derived 2)-like 2 (NRF2) activity, increased antioxidant gene expression, and reduced macrophage reactive oxygen species (ROS) production and hepatic apoptosis/necroptosis in IR-stressed livers. Mechanistically, macrophage TXNIP deficiency promoted cylindromatosis (CYLD), which colocalised and interacted with NADPH oxidase 4 (NOX4) to enhance NRF2 activity by deubiquitinating NOX4. Disruption of macrophage NRF2 or its target gene 2',5' oligoadenylate synthetase-like 1 (OASL1) enhanced Ras GTPase-activating protein-binding protein 1 (G3BP1) and TBK1-mediated inflammatory response. Notably, macrophage OASL1 deficiency induced hepatocyte apoptotic peptidase activating factor 1 (APAF1), cytochrome c, and caspase-9 activation, leading to increased caspase-3-initiated apoptosis and receptor-interacting serine/threonine-protein kinase 3 (RIPK3)-mediated necroptosis.ConclusionsMacrophage TXNIP deficiency enhances CYLD activity and activates the NRF2-OASL1 signalling, controlling IR stress-induced liver injury. The target gene OASL1 regulated by NRF2 is crucial for modulating STING-mediated TBK1 activation and Apaf1/cytochrome c/caspase-9-triggered apoptotic/necroptotic cell death pathway. Our findings underscore a novel role of macrophage TXNIP-mediated CYLD-NRF2-OASL1 axis in stress-induced liver inflammation and cell death, implying the potential therapeutic targets in liver inflammatory diseases.Lay summaryLiver inflammation and injury induced by ischaemia and reperfusion (the absence of blood flow to the liver tissue followed by the resupply of blood) is a significant cause of hepatic dysfunction and failure following liver transplantation, resection, and haemorrhagic shock. Herein, we uncover an underlying mechanism that contributes to liver inflammation and cell death in this setting and could be a therapeutic target in stress-induced liver inflammatory injury.

Abstract The crosstalk between astrocytes and microglia plays a pivotal role in neuroinflammation following ischemic stroke, and phenotypic distribution of these cells can change with the progression of ischemic stroke. Peroxiredoxin (PRDX) 6 phospholipase A2 (iPLA2) activity is involved in the generation of reactive oxygen species(ROS), with ROS driving the activation of microglia and astrocytes; however, its exact function remains unexplored. MJ33, PRDX6D140A mutation was used to block PRDX6-iPLA2 activity in vitro and vivo after ischemic stroke. PRDX6T177A mutation was used to block the phosphorylation of PRDX6 in CTX-TNA2 cell lines. NAC, GSK2795039, Mdivi-1, U0126, and SB202190 were used to block the activity of ROS, NOX2, mitochondrial fission, ERK, and P38, respectively, in CTX-TNA2 cells. In ischemic stroke, PRDX6 is mainly expressed in astrocytes and PRDX6-iPLA2 is involved in the activation of astrocytes and microglia. In co-culture system, Asp140 mutation in PRDX6 of CTX-TNA2 inhibited the polarization of microglia, reduced the production of ROS, suppressed NOX2 activation, and inhibited the Drp1-dependent mitochondrial fission following OGD/R. These effects were further strengthened by the inhibition of ROS production. In subsequent experiments, U0126 and SB202190 inhibited the phosphorylation of PRDX6 at Thr177 and reduced PRDX6-iPLA2 activity. These results suggest that PRDX6-iPLA2 plays an important role in the astrocyte-induced generation of ROS and activation of microglia, which are regulated by the activation of Nox2 and Drp1-dependent mitochondrial fission pathways. Additionally, PRDX6-iPLA2 activity is regulated by MAPKs via the phosphorylation of PRDX6 at Thr177 in astrocytes.

M2-polarized, tumor-associated macrophages (TAMs) produce pro-tumorigenic and angiogenic mediators, such as interleukin-8 (IL-8) and IL-10. Leucine-rich repeat-containing protein 8 members (LRRC8s) form volume-regulated anion channels and play an important role in macrophage functions by regulating cytokine and chemokine production. We herein examined the role of LRRC8A in IL-8 and IL-10 expression in THP-1-differentiated M2-like macrophages (M2-MACs), which are a useful tool for investigating TAMs. In M2-MACs, the pharmacological inhibition of LRRC8A led to hyperpolarizing responses after a transient depolarization phase, followed by a slight elevation in the intracellular concentration of Ca2+. Both the small interfering RNA-mediated and pharmacological inhibition of LRRC8A repressed the transcriptional expression of IL-8 and IL-10, resulting in a significant reduction in their secretion. The inhibition of LRRC8A decreased the nuclear translocation of phosphorylated nuclear factor-erythroid 2-related factor 2 (Nrf2), while the activation of Nrf2 reversed the LRRC8A inhibition-induced transcriptional repression of IL-8 and IL-10 in M2-MACs. We identified the CCAAT/enhancer-binding protein isoform B, CEBPB, as a downstream target of Nrf2 signaling in M2-MACs. Moreover, among several upstream candidates, the inhibition of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) suppressed the Nrf2–CEBPB transcriptional axis in M2-MACs. Collectively, the present results indicate that the inhibition of LRRC8A repressed IL-8 and IL-10 transcription in M2-MACs through the NOX2–Nrf2–CEBPB axis and suggest that LRRC8A inhibitors suppress the IL-10-mediated evasion of tumor immune surveillance and IL-8-mediated metastasis and neovascularization in TAMs.

The crosstalk between astrocytes and microglia plays a pivotal role in neuroinflammation following ischemic stroke, and phenotypic distribution of these cells can change with the progression of ischemic stroke. Peroxiredoxin (PRDX) 6 phospholipase A2 (iPLA2) activity is involved in the generation of reactive oxygen species(ROS), with ROS driving the activation of microglia and astrocytes; however, its exact function remains unexplored. MJ33, PRDX6D140A mutation was used to block PRDX6-iPLA2 activity in vitro and vivo after ischemic stroke. PRDX6T177A mutation was used to block the phosphorylation of PRDX6 in CTX-TNA2 cell lines. NAC, GSK2795039, Mdivi-1, U0126, and SB202190 were used to block the activity of ROS, NOX2, mitochondrial fission, ERK, and P38, respectively, in CTX-TNA2 cells. In ischemic stroke, PRDX6 is mainly expressed in astrocytes and PRDX6-iPLA2 is involved in the activation of astrocytes and microglia. In co-culture system, Asp140 mutation in PRDX6 of CTX-TNA2 inhibited the polarization of microglia, reduced the production of ROS, suppressed NOX2 activation, and inhibited the Drp1-dependent mitochondrial fission following OGD/R. These effects were further strengthened by the inhibition of ROS production. In subsequent experiments, U0126 and SB202190 inhibited the phosphorylation of PRDX6 at Thr177 and reduced PRDX6-iPLA2 activity. These results suggest that PRDX6-iPLA2 plays an important role in the astrocyte-induced generation of ROS and activation of microglia, which are regulated by the activation of Nox2 and Drp1-dependent mitochondrial fission pathways. Additionally, PRDX6-iPLA2 activity is regulated by MAPKs via the phosphorylation of PRDX6 at Thr177 in astrocytes. [ABSTRACT FROM AUTHOR]

Introduction: Short episodes of ischemia-reperfusion (IR) in the heart (classical ischemic preconditioning, IPC) or in a limb (remote ischemic preconditioning, RIPC) before a prolonged ischemic episode, reduce the size of the infarct. It is unknown whether IPC and RIPC share common mechanisms of protection. Animals KO for NOX2, a superoxide-producing enzyme, or KO for NLRP3, a protein component of inflammasome, are not protected by IPC. The aim of this study was to investigate if NOX2 or NLRP3 inflammasome are involved in the protection induced by RIPC. Methods: We preconditioned rats using 4 x 5 min periods of IR in the limb with or without a NOX2 inhibitor (apocynin) or an NLRP3 inhibitor (Bay117082). In isolated hearts, we measured the infarct size after 30 min of ischemia and 60 min of reperfusion. In hearts from preconditioned rats we measured the activity of NOX2; the mRNA of Nrf2, gamma-glutamylcysteine ligase, glutathione dehydrogenase, thioredoxin reductase and sulfiredoxin by RT-qPCR; the content of glutathione; the activation of the NLRP3 inflammasome and the content of IL-1β and IL-10 in cardiac tissue. In exosomes isolated from plasma, we quantified NOX2 activity. Results: The infarct size after IR decreased from 40% in controls to 9% of the heart volume after RIPC. This protective effect was lost in the presence of both inhibitors. RIPC increased NOX2 activity in the heart and exosomes, as indicated by the increased association of p47phox to the membrane and by the increased oxidation rate of NADPH. RIPC also increased the mRNA of Nrf2 and antioxidant enzymes. Also, RIPC increased the content of glutathione and the GSH/GSSG ratio. The inflammasome proteins NLRP3, procaspase-1, and caspase-1 were all increased in the hearts of RIPC rats. At the end of RIPC protocol, IL-1β increased in plasma but decreased in cardiac tissue. At the same time, IL-10 did not change in cardiac tissue but increased by 70% during the next 50 min of perfusion. Conclusion: RIPC activates NOX2 which upregulates the heart's antioxidant defenses and activates the NLRP3 inflammasome which stimulates a cardiac anti-inflammatory response. These changes may underlie the decrease in the infarct size induced by RIPC. [ABSTRACT FROM AUTHOR]

Background: Excess reactive oxygen species generated by NADPH oxidase 2 (Nox2) in response to ethanol exposure mediate aspects of skeletal toxicity including increased osteoclast differentiation and activity. Because perturbation of chondrocyte differentiation in the growth plate by ethanol could be prevented by dietary antioxidants, we hypothesized that Nox2 in the growth plate was involved in ethanol‐associated reductions in longitudinal bone growth. Methods: Nox2 conditional knockout mice were generated, where the essential catalytic subunit of Nox2, cytochrome B‐245 beta chain (Cybb), is deleted in chondrocytes using a Cre‐Lox model with Cre expressed from the collagen 2a1 promoter (Col2a1‐Cre). Wild‐type and Cre‐Lox mice were fed an ethanol Lieber‐DeCarli‐based diet or pair‐fed a control diet for 8 weeks. Results: Ethanol treatment significantly reduced the number of proliferating chondrocytes in the growth plate, enhanced bone marrow adiposity, shortened femurs, reduced body length, reduced cortical bone volume, and decreased mRNA levels of a number of osteoblast and chondrocyte genes. Conditional knockout of Nox2 enzymatic activity in chondrocytes did not consistently prevent any ethanol effects. Rather, knockout mice had fewer proliferating chondrocytes than wild‐type mice in both the ethanol‐ and control‐fed animals. Additional analysis of tibia samples from Nox4 knockout mice showed that loss of Nox4 activity also reduced the number of proliferating chondrocytes and altered chondrocyte size in the growth plate. Conclusions: Although Nox enzymatic activity regulates growth plate development, ethanol‐associated disruption of the growth plate morphology is independent of ethanol‐mediated increases in Nox2 activity. [ABSTRACT FROM AUTHOR]

Objective: To investigate the role of Nox2 on AngII-stimulated aldosterone biosynthesis. Methods: H295R cells were cultured and randomly divided into control group, Angll group, AngII+gp91ds-tat group, AngII+PEG-Cat group, AngII+Nox2 siRNA group. Q-PCR and western blot were performed to determine CYP1IB2 and Nox2 expression in H295R cells. Aldosterone level in cells culture supernatant was determined by radioimmunoassay. Nox2-derived ROS and H2O2 production in H295R cells were determined by flow cytometric analysis and fluorescence microplate reader. Results: 10 nmol/L Angll increased cellular ROS and H2O2 generation, increased the Nox2 and CYP11B2 expression and accelerated aldosterone biosynthesis in a time-dependent manner (P<0.05). And AngII-induced cellular ROS and H₂O, production in both AngII+gp91ds-tat and AngII+PEG-Cat groups were lower than those in AngII group (P<0.05). However, there were no difference in inhibition of cellular ROS and H2O2 between treatment with gp91ds-tat and PEG-Cat (P>0.05). The expression of CYP11B2 in H295R cells was up-regulated after treated with 10 nmol/L Angll for 24 h (P<0.05), while gp91ds-tat, PEG-Cat and Nox2 siRNA significantly abrogated the CYP11B2 expression in H295R cells (P<0.05). Conclusion: Nox2 dependent ROS play an important role in aldosterone synthesis. [ABSTRACT FROM AUTHOR]

Background. Eccentric exercise may trigger mechanical stress, resulting in muscle damage that may decrease athletic performance. L-citrulline potentially prevents skeletal muscle damage after acute eccentric exercise. This study aimed to assess the dose-response effect of L-citrulline as a preventive therapy for skeletal muscle damage in mice after acute eccentric exercise. Methods. This is a controlled laboratory in vivo study with a post-test-only design. Male mice (BALB/c, n=25) were randomized into the following groups: a normal control (C1) (n=5); a negative control (C2) with downhill running and placebo intervention (n=5); treatment groups: T1 (n=5), T2 (n=5), and T3 (n=5), were subjected to downhill running and 250, 500, and 1,000 mg/kg of L-citrulline, respectively, for seven days. Blood plasma was used to determine the levels of TNNI2 and gastrocnemius muscle tissue NOX2, IL-6, and caspase 3 using ELISA. NF-χB and HSP-70 expressions were determined by immunohistochemistry. Results. Skeletal muscle damage (plasma TNNI2 levels) in mice after eccentric exercise was lower after 250 and 500 mg/kg of L-citrulline. Further, changes in oxidative stress markers, NOX2, were reduced after a 1,000 mg/kg dose. However, a lower level of change has been observed in levels of cellular response markers (NF-κB, HSP-70, IL-6, and caspase 3) after administration of L-citrulline doses of 250, 500, and 1,000 mg/kg. Conclusion. L-citrulline may prevent skeletal muscle damage in mice after acute eccentric exercise through antioxidant effects as well as inflammatory and apoptotic pathways. In relation to dose-related effects, it was found that L-citrulline doses of 250, 500, and 1,000 mg/kg significantly influenced the expression of NF-κB and HSP-70, as well as the levels of IL-6 and caspase 3. Meanwhile, only doses of 250 and 500 mg/kg had an impact on TNNI2 levels, and the 1,000 mg/kg dose affected NOX2 levels. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EVs) are a type of cytoplasmic vesicles secreted by a variety of cells. EVs originating from cells have been known to participate in cell communication, antigen presentation, immune cell activation, tolerance induction, etc. These EVs can also carry the active form of Nicotinamide Adenine Dinucleotide Phosphate Oxidase Hydrogen (NADPH) oxidase, which is very essential for the production of reactive oxygen species (ROS) and that can then modulate processes such as cell regeneration. The aim of this study is to characterize the EVs isolated from U-937 and THP-1 cells, identify the NADPH oxidase (NOX) isoforms, and to determine whether EVs can modulate NOX4 and NOX2 in monocytes and macrophages. In our study, isolated EVs of U-937 were characterized using dynamic light scattering (DLS) spectroscopy and immunoblotting. The results showed that the exogenous addition of differentiation agents (either phorbol 12-myristate 13-acetate (PMA) or ascorbic acid) or the supplementation of EVs used in the study did not cause any stress leading to alterations in cell proliferation and viability. In cells co-cultured with EVs for 72 h, strong suppression of NOX4 and NOX2 is evident when monocytes transform into macrophagic cells. We also observed lower levels of oxidative stress measured using immunoblotting and electron paramagnetic resonance spectroscopy under the EVs co-cultured condition, which also indicates that EVs might contribute significantly by acting as an antioxidant source, which agrees with previous studies that hypothesized the role of EVs in therapeutics. Therefore, our results provide evidence for NOX regulation by EVs in addition to its role as an antioxidant cargo.

Abstract Background According to WHO 2020, CAD is the second leading cause of death in Indonesia with death cases reaching 259,297 or 15.33% of total deaths. Unfortunately, most of the patients of CAD in Indonesia did not match the golden period or decline to be treated with Percutaneous Coronary Intervention (PCI). Based on the recent study, there were increases in MMP-9, NOX2, and TGF-β1 in STEMI patients which contribute to cardiac remodeling. Moreover, there is controversy regarding the benefit of late PCI (12-48 hours after onset of STEMI) in stable patients. Lately, colchicine is widely used in cardiovascular disease. This study was conducted to explore the effect of colchicine to reduce MMP- 9, NOX2, and TGF-β1 levels after myocardial infarction in stable patients. Method In this clinical trial study, we assessed 129 STEMI patients, about 102 patients who met inclusion criteria were randomized into four groups. Around 25 patients received late PCI (12–48 h after the onset of chest pain), optimal medical treatment (OMT) for STEMI, and colchicine; 24 patients received late PCI and OMT; 22 patients didn’t get the revascularization (No Revas), OMT, and colchicine; and 31 patients received No Revas and OMT only. The laboratory test for MMP-9, NOX2, and TGF-β1 were tested in Day-1 and Day-5. The data were analyzed using Mann-Whitney. Results A total of 102 patients with mean age of 56 ± 9.9, were assigned into four groups. The data analysis showed significant results within No Revas + OMT + Colchicine group versus No Revas + OMT + Placebo in MMP-9 (Day-1: p = 0.001; Day-5: p = 0.022), NOX2 (Day-1: p = 0.02; Day-5: p = 0.026), and TGF-β1 (Day-1: p = 0.00; Day-5: p = 0.00) with the less three markers in OMT + Colchicine group than OMT + Placebo group. There were no significant differences within the late PCI + OMT + colchicine group and PCI + OMT + Placebo group. Conclusions Colchicine could significantly reduce MMP-9, NOX2, and TGF-β1 levels in stable STEMI patients. So that, colchicine could be a potential agent in STEMI patients and prevent cardiac remodeling events.

Neutrophil extracellular traps (NETs) are three-dimensional reticular structures that release chromatin and cellular contents extracellularly upon neutrophil activation. As a novel effector mechanism of neutrophils, NETs possess the capacity to amplify localized inflammation and have been demonstrated to contribute to the exacerbation of various inflammatory diseases, including cardiovascular diseases and tumors. It is suggested that lysophosphatidylcholine (LPC), as the primary active component of oxidized low-density lipoprotein, represents a significant risk factor for various inflammatory diseases, such as cardiovascular diseases and neurodegenerative diseases. However, the specific mechanism of NETs formation induced by LPC remains unclear. Quercetin has garnered considerable attention due to its anti-inflammatory properties, serving as a prevalent flavonoid in daily diet. However, little is currently known about the underlying mechanisms by which quercetin inhibits NETs formation and alleviates associated diseases. In our study, we utilized LPC-treated primary rat neutrophils to establish an in vitro model of NETs formation, which was subsequently subjected to treatment with a combination of quercetin or relevant inhibitors/activators. Compared to the control group, the markers of NETs and the expression of P2X7R/P38MAPK/NOX2 pathway-associated proteins were significantly increased in cells treated with LPC alone. Quercetin intervention decreased the LPC-induced upregulation of the P2X7R/P38MAPK/NOX2 pathway and effectively reduced the expression of NETs markers. The results obtained using a P2X7R antagonist/activator and P38MAPK inhibitor/activator support these findings. In summary, quercetin reversed the upregulation of the LPC-induced P2X7R/P38MAPK/NOX2 pathway, further mitigating NETs formation. Our study investigated the potential mechanism of LPC-induced NETs formation, elucidated the inhibitory effect of quercetin on NETs formation, and offered new insights into the anti-inflammatory properties of quercetin.

The outbreak of COVID-19 has remained uncontained with urgent need for robust therapeutics. We have previously reported sex difference of COVID-19 for the first time indicating male predisposition. Males are more susceptible than females, and more often to develop into severe cases with higher mortality. This predisposition is potentially linked to higher prevalence of cigarette smoking. Nonetheless, we found for the first time that cigarette smoking extract (CSE) had no effect on angiotensin converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) expression in endothelial cells. The otherwise observed worse outcomes in smokers is likely linked to baseline respiratory diseases associated with chronic smoking. Instead, we hypothesized that estrogen mediated protection might underlie lower morbidity, severity and mortality of COVID-19 in females. Of note, endothelial inflammation and barrier dysfunction are major mediators of disease progression, and development of acute respiratory distress syndrome (ARDS) and multi-organ failure in patients with COVID-19. Therefore, we investigated potential protective effects of estrogen on endothelial cells against oxidative stress induced by interleukin-6 (IL-6) and SARS-CoV-2 spike protein (S protein). Indeed, 17β-estradiol completely reversed S protein-induced selective activation of NADPH oxidase isoform 2 (NOX2) and reactive oxygen species (ROS) production that are ACE2-dependent, as well as ACE2 upregulation and induction of pro-inflammatory gene monocyte chemoattractant protein-1 (MCP-1) in endothelial cells to effectively attenuate endothelial dysfunction. Effects of IL-6 on activating NOX2-dependent ROS production and upregulation of MCP-1 were also completely attenuated by 17β-estradiol. Of note, co-treatment with CSE had no additional effects on S protein stimulated endothelial oxidative stress, confirming that current smoking status is likely unrelated to more severe disease in chronic smokers. These data indicate that estrogen can serve as a novel therapy for patients with COVID-19 via inhibition of initial viral responses and attenuation of cytokine storm induced endothelial dysfunction, to substantially alleviate morbidity, severity and mortality of the disease, especially in men and post-menopause women. Short-term administration of estrogen can therefore be readily applied to the clinical management of COVID-19 as a robust therapeutic option.

Background Nitric oxide (NO) is the most important vasodilator secreted by vascular endothelial cells, and its abnormal synthesis is involved in the development of cardiovascular disease. The prenatal period is a critical time for development and largely determines lifelong vascular health in offspring. Given the high incidence and severity of gestational hypoxia in mid‐late pregnancy, it is urgent to further explore whether it affects the long‐term synthesis of NO in offspring vascular endothelial cells. Methods and Results Pregnant Sprague–Dawley rats were housed in a normoxic or hypoxic (10.5% O2) chamber from gestation days 10 to 20. The thoracic aortas of fetal and adult male offspring were isolated for experiments. Gestational hypoxia significantly reduces the NO‐dependent vasodilation mediated by acetylcholine in both the fetal and adult offspring thoracic aorta rings. Meanwhile, acetylcholine‐induced NO synthesis is impaired in vascular endothelial cells from hypoxic offspring thoracic aortas. We demonstrate that gestational hypoxic offspring exhibit a reduced endothelial NO synthesis capacity, primarily due to increased expression of NADPH oxidase 2 and enhanced reactive oxygen species. Additionally, gestational hypoxic offspring show elevated levels of miR‐155‐5p in vascular endothelial cells, which is associated with increased expression of NADPH oxidase 2 and reactive oxygen species generation, as well as impaired NO synthesis. Conclusions The present study is the first to demonstrate that gestational hypoxia impairs endothelial NO synthesis via the miR‐155‐5p/NADPH oxidase 2/reactive oxygen species axis in offspring vessels. These novel findings indicate that the detrimental effects of gestational hypoxia on fetal vascular function can persist into adulthood, providing new insights into the development of vascular diseases.

Introduction: Short episodes of ischemia-reperfusion (IR) in the heart (classical ischemic preconditioning, IPC) or in a limb (remote ischemic preconditioning, RIPC) before a prolonged ischemic episode, reduce the size of the infarct. It is unknown whether IPC and RIPC share common mechanisms of protection. Animals KO for NOX2, a superoxide-producing enzyme, or KO for NLRP3, a protein component of inflammasome, are not protected by IPC. The aim of this study was to investigate if NOX2 or NLRP3 inflammasome are involved in the protection induced by RIPC.Methods: We preconditioned rats using 4 × 5 min periods of IR in the limb with or without a NOX2 inhibitor (apocynin) or an NLRP3 inhibitor (Bay117082). In isolated hearts, we measured the infarct size after 30 min of ischemia and 60 min of reperfusion. In hearts from preconditioned rats we measured the activity of NOX2; the mRNA of Nrf2, gamma-glutamylcysteine ligase, glutathione dehydrogenase, thioredoxin reductase and sulfiredoxin by RT-qPCR; the content of glutathione; the activation of the NLRP3 inflammasome and the content of IL-1β and IL-10 in cardiac tissue. In exosomes isolated from plasma, we quantified NOX2 activity.Results: The infarct size after IR decreased from 40% in controls to 9% of the heart volume after RIPC. This protective effect was lost in the presence of both inhibitors. RIPC increased NOX2 activity in the heart and exosomes, as indicated by the increased association of p47phox to the membrane and by the increased oxidation rate of NADPH. RIPC also increased the mRNA of Nrf2 and antioxidant enzymes. Also, RIPC increased the content of glutathione and the GSH/GSSG ratio. The inflammasome proteins NLRP3, procaspase-1, and caspase-1 were all increased in the hearts of RIPC rats. At the end of RIPC protocol, IL-1β increased in plasma but decreased in cardiac tissue. At the same time, IL-10 did not change in cardiac tissue but increased by 70% during the next 50 min of perfusion.Conclusion: RIPC activates NOX2 which upregulates the heart’s antioxidant defenses and activates the NLRP3 inflammasome which stimulates a cardiac anti-inflammatory response. These changes may underlie the decrease in the infarct size induced by RIPC.

Background Eccentric exercise may trigger mechanical stress, resulting in muscle damage that may decrease athletic performance. L-citrulline potentially prevents skeletal muscle damage after acute eccentric exercise. This study aimed to assess the dose-response effect of L-citrulline as a preventive therapy for skeletal muscle damage in mice after acute eccentric exercise. Methods This is a controlled laboratory in vivo study with a post-test-only design. Male mice (BALB/c, n = 25) were randomized into the following groups: a normal control (C1) (n = 5); a negative control (C2) with downhill running and placebo intervention (n = 5); treatment groups: T1 (n = 5), T2 (n = 5), and T3 (n = 5), were subjected to downhill running and 250, 500, and 1,000 mg/kg of L-citrulline, respectively, for seven days. Blood plasma was used to determine the levels of TNNI2 and gastrocnemius muscle tissue NOX2, IL-6, and caspase 3 using ELISA. NF-κB and HSP-70 expressions were determined by immunohistochemistry. Results Skeletal muscle damage (plasma TNNI2 levels) in mice after eccentric exercise was lower after 250 and 500 mg/kg of L-citrulline. Further, changes in oxidative stress markers, NOX2, were reduced after a 1,000 mg/kg dose. However, a lower level of change has been observed in levels of cellular response markers (NF-κB, HSP-70, IL-6, and caspase 3) after administration of L-citrulline doses of 250, 500, and 1,000 mg/kg. Conclusion L-citrulline may prevent skeletal muscle damage in mice after acute eccentric exercise through antioxidant effects as well as inflammatory and apoptotic pathways. In relation to dose-related effects, it was found that L-citrulline doses of 250, 500, and 1,000 mg/kg significantly influenced the expression of NF-κB and HSP-70, as well as the levels of IL-6 and caspase 3. Meanwhile, only doses of 250 and 500 mg/kg had an impact on TNNI2 levels, and the 1,000 mg/kg dose affected NOX2 levels.

Acute myeloid leukaemia (AML) is a highly heterogeneous disease, however the therapeutic approaches have hardly changed in the last decades. Metabolism rewiring and the enhanced production of reactive oxygen species (ROS) are hallmarks of cancer. A deeper understanding of these features could be instrumental for the development of specific AML-subtypes treatments. NADPH oxidases (NOX), the only cellular system specialised in ROS production, are also involved in leukemic metabolism control. NOX2 shows a variable expression in AML patients, so patients can be classified based on such difference. Here we have analysed whether NOX2 levels are important for AML metabolism control. The lack of NOX2 in AML cells slowdowns basal glycolysis and oxidative phosphorylation (OXPHOS), along with the accumulation of metabolites that feed such routes, and a sharp decrease of glutathione. In addition, we found changes in the expression of 725 genes. Among them, we have discovered a panel of 30 differentially expressed metabolic genes, whose relevance was validated in patients. This panel can segregate AML patients according to CYBB expression, and it can predict patient prognosis and survival. In summary, our data strongly support the relevance of NOX2 for AML metabolism, and highlights the potential of our discoveries in AML prognosis. [Display omitted] • NOX2 deletion reduces glycolysis and mitochondrial respiration in AML cells. • NOX2 deletion enables activation of lipid metabolism more efficiently. • A panel of 30 metabolic genes differentially expressed in NOX2-deficient cells predicts AML patient prognostic and survival. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cortical contusion TBI caused a rapid inflammatory response in the olfactory bulb. • Increased Hv1 and NOX2 in the OB were accompanied by elevated ROS production. • TBI induced early neuronal hyperexcitation and later hypo-neuronal activity in the OB. • TBI-disrupted OB neuronal network function was improved in the Hv1 KO mice. • Blocking or inhibiting Hv1/NOX2 signaling improved TBI-mediate olfactory dysfunction. Approximately 20–68% of traumatic brain injury (TBI) patients exhibit trauma-associated olfactory deficits (OD) which can compromise not only the quality of life but also cognitive and neuropsychiatric functions. However, few studies to date have examined the impact of experimental TBI on OD. The present study examined inflammation and neuronal dysfunction in the olfactory bulb (OB) and the underlying mechanisms associated with OD in male mice using a controlled cortical impact (CCI) model. TBI caused a rapid inflammatory response in the OB as early as 24 h post-injury, including elevated mRNA levels of proinflammatory cytokines, increased numbers of microglia and infiltrating myeloid cells, and increased IL1β and IL6 production in these cells. These changes were sustained for up to 90 days after TBI. Moreover, we observed significant upregulation of the voltage-gated proton channel Hv1 and NOX2 expression levels, which were predominantly localized in microglia/macrophages and accompanied by increased reactive oxygen species production. In vivo OB neuronal firing activities showed early neuronal hyperexcitation and later hypo-neuronal activity in both glomerular layer and mitral cell layer after TBI, which were improved in the absence of Hv1. In a battery of olfactory behavioral tests, WT/TBI mice displayed significant OD. In contrast, neither Hv1 KO/TBI nor NOX2 KO/TBI mice showed robust OD. Finally, seven days of intranasal delivery of a NOX2 inhibitor (NOX2ds-tat) ameliorated post-traumatic OD. Collectively, these findings highlight the importance of OB neuronal networks and its role in TBI-mediated OD. Thus, targeting Hv1/NOX2 may be a potential intervention for improving post-traumatic anosmia. [ABSTRACT FROM AUTHOR]

Delayed appendicitis diagnosis may result in perforation and an increased risk of mortality. This study aimed to assess the diagnostic value of ischemia-modified albumin, nicotinamide adenine dinucleotide phosphate oxidase 1, 2, and 4 levels in the diagnosis of non-complicated and complicated appendicitis. The study included 60 pediatric patients who presented to our clinic with a complaint of abdominal pain and underwent surgery with a diagnosis of appendicitis between November 2020 and December 2021 and also included 30 controls. Cases were divided into three groups: (i) non-complicated appendicitis (n = 30), (ii) complicated appendicitis (n = 30), and (iii) control (n = 30). The nicotinamide adenine dinucleotide phosphate oxidase 1 and 4 and ischemia-modified albumin levels were higher in non-complicated and complicated appendicitis compared to the control (p < 0.001). In addition, considering the odds ratio values, the most effective biomarkers in the diagnosis were nicotinamide adenine dinucleotide phosphate oxidase 1 and 2, and procalcitonin, while the most effective biomarkers in the prognosis were nicotinamide adenine dinucleotide phosphate oxidase 1 and 2, and neotrophil/lymphocyte ratios. The data suggested that since the most successful biomarker nicotinamide adenine dinucleotide phosphate oxidase 1, with a value of 0.98- area under the curve, is the most successful biomarker in both diagnosis and prognosis of the disease, it can be used as an important biomarker in childhood appendicitis. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and its prevalence increases with age. The irregular and rapid contraction of the atria can lead to ineffective blood pumping, local blood stasis, blood clots, ischemic stroke, and heart failure. NADPH oxidases (NOX) and mitochondria are the main sources of reactive oxygen species in the heart, and dysregulated activation of NOX and mitochondrial dysfunction are associated with AF pathogenesis. NOX- and mitochondria-derived oxidative stress contribute to the onset of paroxysmal AF by inducing electrophysiological changes in atrial myocytes and structural remodeling in the atria. Because high atrial activity causes cardiac myocytes to expend extremely high energy to maintain excitation-contraction coupling during persistent AF, mitochondria, the primary energy source, undergo metabolic stress, affecting their morphology, Ca2+ handling, and ATP generation. In this review, we discuss the role of oxidative stress in activating AF-triggered activities, regulating intracellular Ca2+ handling, and functional and anatomical reentry mechanisms, all of which are associated with AF initiation, perpetuation, and progression. Changes in the extracellular matrix, inflammation, ion channel expression and function, myofibril structure, and mitochondrial function occur during the early transitional stages of AF, opening a window of opportunity to target NOX and mitochondria-derived oxidative stress using isoform-specific NOX inhibitors and mitochondrial ROS scavengers, as well as drugs that improve mitochondrial dynamics and metabolism to treat persistent AF and its transition to permanent AF. [ABSTRACT FROM AUTHOR]

Clinical studies implicated an increased risk of intestinal fibrosis in patients with nonalcoholic fatty liver disease (NAFLD). Our previous studies have shown that microcystin-LR (MC-LR) exposure led to altered gut microbiome and increased abundance of lactate producing bacteria and intestinal inflammation in underlying NAFLD. This led us to further investigate the effects of the MC-LR, a PP2A inhibitor in activating the TGF-β fibrotic pathway in the intestines that might be mediated by increased lactate induced redox enzyme NOX2. Exposure to MC-LR led to higher lactate levels in circulation and in the intestinal content. The higher lactate levels were associated with NOX2 activation in vivo that led to increased Smad2/3-Smad4 co-localization and high alpha-smooth muscle actin (α-SMA) immunoreactivity in the intestines. Mechanistically, primary mouse intestinal epithelial cells treated with lactate and MC-LR separately led to higher NOX2 activation, phosphorylation of TGFβR1 receptor and subsequent Smad 2/3-Smad4 co-localization inhibitable by apocynin (NOX2 inhibitor), FBA (a peroxynitrite scavenger) and DMPO (a nitrone spin trap), catalase and superoxide dismutase. Inhibition of NOX2-induced redox signaling also showed a significant decrease in collagen protein thus suggesting a strong redox signaling induced activation of an ectopic fibrotic manifestation in the intestines. In conclusion, the present study provides mechanistic insight into the role of microcystin in dysbiosis-linked lactate production and subsequently advances our knowledge in lactate-induced NOX2 exacerbation of the cell differentiation and fibrosis in the NAFLD intestines.

Cerebral malaria (CM), a severe neurological pathology caused by Plasmodium falciparum infection, poses a significant global health threat and has a high mortality rate. Conventional therapeutics cannot cross the blood–brain barrier (BBB) efficiently. Therefore, finding effective treatments remains challenging. The novelty of the treatment proposed in this study lies in the feasibility of intranasal (IN) delivery of the nanostructured lipid carrier system (NLC) combining microRNA (miRNA) and artemether (ARM) to enhance bioavailability and brain targeting. The rational use of NLCs and RNA-targeted therapeutics could revolutionize the treatment strategies for CM management. This study can potentially address the challenges in treating CM, allowing drugs to pass through the BBB. The NLC formulation was developed by a hot-melt homogenization process utilizing 3% (w/w) precirol and 1.5% (w/v) labrasol, resulting in particles with a size of 94.39 nm. This indicates an effective delivery to the brain via IN administration. The results further suggest the effective intracellular delivery of encapsulated miRNAs in the NLCs. Investigations with an experimental cerebral malaria mouse model showed a reduction in parasitaemia, preservation of BBB integrity, and reduced cerebral haemorrhages with the ARM+ miRNA-NLC treatment. Additionally, molecular discoveries revealed that nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) and Interleukin-6 (IL-6) levels were reduced in the treated groups in comparison to the CM group. These results support the use of nanocarriers for IN administration, offering a viable method for mitigating CM through the increased bioavailability of therapeutics. Our findings have far-reaching implications for future research and personalized therapy.

Traumatic brain injury (TBI) is caused by acquired damage that includes cerebral edema after a mechanical injury and may cause cognitive impairment. We explored the role of nicotinamide adenine dinucleotide phosphate oxidase 2 (NADPH oxidase 2; NOX2) and aquaporin-4 (AQP4) in the process of edema and cognitive abilities after TBI in NOX2−/− and AQP4−/− mice by using the Morris water maze test (MWM), step-down test (STD), novel object recognition test (NOR) and western blotting. Knockout of NOX2 in mice decreased the AQP4 and reduce edema in the hippocampus and cortex after TBI in mice. Moreover, inhibiting AQP4 by 2-(nicotinamide)-1,3,4-thiadiazole (TGN-020) or genetic deletion of AQP4 could attenuate neurological deficits without changing reactive oxygen species (ROS) levels after TBI in mice. Taken together, we suspected that inhibiting NOX2 could improve cognitive abilities by modulating ROS levels, then affecting AQP4 levels and brain edema after in TBI mice. Our study demonstrated that NOX2 play a key role in decreasing edema in brain and improving cognitive abilities by modulating AQP4 after TBI.

TNFα-mediated signaling pathways play a pivotal role in the pathogenesis of inflammatory diseases such as rheumatoid arthritis (RA) and inflammatory bowel disease (IBD) by promoting phagocyte inflammatory functions, notably cytokine release and reactive oxygen species (ROS) production by NOX2. In contrast, interleukin-10 (IL-10), a powerful anti-inflammatory cytokine, potently shuts down phagocyte activation, making IL-10 an attractive therapeutic candidate. However, IL-10 therapy has shown limited efficacy in patients with inflammatory diseases. Here, we report that TNFα blocks IL-10 anti-inflammatory pathways in human monocytes, thereby prolonging inflammation. TNFα decreased IL-10-induced phosphorylation of STAT3 and consequently IL-10-induced expression of the major anti-inflammatory factor, SOCS3. Decreased STAT3 phosphorylation was due to a SHP1/2 phosphatase, as NSC-87877, a SHP1/2 inhibitor, restored STAT3 phosphorylation and prevented the TNFα-induced inhibition of IL-10 signaling. TNFα activated only SHP1 in human monocytes and this activation was NOX2-dependent, as diphenyleneiodonium, a NOX2 inhibitor, suppressed SHP1 activation and STAT3 dephosphorylation triggered by TNFα. ROS-induced activation of SHP1 was mediated by the redox-sensitive kinase, Lyn, as its inhibition impeded TNFα-induced SHP1 activation and STAT3 dephosphorylation. Furthermore, H2O2 recapitulated TNFα-inhibitory activity on IL-10 signaling. Finally, NSC-87877 dampened collagen antibody-induced arthritis (CAIA) in mice. These results reveal that TNFα disrupts IL-10 signaling by inducing STAT3 dephosphorylation through a NOX2-ROS-Lyn-SHP1 axis in human monocytes and that inhibition of SHP1/2 in vivo protects against CAIA. These new findings might explain the poor efficacy of IL-10 therapy in patients with inflammatory diseases and suggest that anti-TNFα agents and SHP1/2 inhibitors could improve the therapeutic use of IL-10.

Increasing evidence shows that polycystic ovary syndrome (PCOS) is often accompanied by an inflammatory response, hence, appropriately managing granulosa cell inflammation is critical to regaining ovarian function in PCOS. In this study, the differential levels of purinergic receptor P2X7 between the control and PCOS samples in the dataset GSE34526 were assessed, then PCOS mouse models were established. Following evaluating the fluctuations in hormone levels, inflammatory cytokines, and P2X7, mice received treatment with the P2X7 antagonist A740003. Its effects on hormones, inflammation, apoptosis, and NOX2 signaling in mice were examined. Afterward, primary mouse granulosa cells were isolated, and the mediating role of NOX2 signaling in the P2X7 regulatory pathway was confirmed by transfection of NOX2 overexpression plasmids. The results demonstrated that P2X7 was significantly elevated in the PCOS samples in the dataset. Compared with the control group, PCOS mice had significant differences in the follicle-stimulating hormone, luteinizing hormone, testosterone, anti-Müllerian hormone, inflammatory factors, and P2X7. Treatment with A740003 partially restored these parameter levels, including NOX2 signaling. Based on in vitro experiments on primary mouse granulosa cells, the above findings were re-verified, and the overexpression of NOX2 could reverse the regulatory function of P2X7. The present study highlights that P2X7 level increases in PCOS, and inhibition of P2X7 can reduce disease symptoms. It is involved in inflammation and apoptosis in granulosa cells through NOX2/JNK signaling. [ABSTRACT FROM AUTHOR]

Amebiasis is an intestinal infection caused by Entamoeba histolytica. Amebic liver abscess (ALA) is the most common extraintestinal complication of amebiasis. In animal models of ALA, neutrophils have been shown to be the first cells to come into contact with Entamoeba histolytica during the initial phase of ALA. One of the multiple mechanisms by which neutrophils exhibit amebicidal activity is through reactive oxygen species (ROS) and the enzyme NADPH oxidase (NOX2), which generates and transports electrons to subsequently reduce molecular oxygen into superoxide anion. Previous reports have shown that ROS release in the susceptible animal species (hamster) is mainly stimulated by the pathogen, in turn provoking such an exacerbated inflammatory reaction that it is unable to be controlled and results in the death of the animal model. Apocynin is a natural inhibitor of NADPH oxidase. No information is available on the role of NOX in the evolution of ALA in the hamster, a susceptible model. Our study showed that administration of a selective NADPH oxidase 2 (NOX2) enzyme inhibitor significantly decreases the percentage of ALA, the size of inflammatory foci, the number of neutrophils, and NOX activity indicated by the reduction in superoxide anion (O2−) production. Moreover, in vitro, the apocynin damages amoebae. Our results showed that apocynin administration induces a decrease in the activity of NOX that could favor a decrease in ALA progression. [ABSTRACT FROM AUTHOR]