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The increased production of reactive oxygen species (ROS) by human neutrophils can lead to oxidative imbalances and several diseases, such as inflammatory bowel disease (IBD). Opuntia ficus-indica (O. ficus-indica) is rich in bioactive substances with anti-inflammatory properties. This study aimed to identify the bioactive compounds present in aqueous cladodes extract (ACE) of O. ficus-indica using high-performance liquid chromatography (HPLC) and to test its effects on human neutrophil inflammatory functions and on ulcerative colitis (UC) induced by acetic acid (Aa) in rats. ROS production and degranulation by neutrophils were assessed by luminol-amplified chemiluminescence, enzymatic techniques, and western blotting. In vivo, the experiment involved seven groups of rats: a negative control group (NaCl), the acetic acid group (Aa), and groups treated with oral sulfasalazine (150 mg/kg) or various doses of ACE for 7 days. Colonic lesions were induced by an intra-rectal Aa injection, and inflammation was assessed. HPLC analysis identified gallic acid, catechin, caffeic acid, and ferulic acid as major compounds in ACE. In vitro, ACE inhibited neutrophil ROS production, including superoxide anion produced by NADPH oxidase, and significantly reduced myeloperoxidase activity and neutrophil degranulation. In vivo, ACE protected rats from Aa-induced histopathological damage of the colonic mucosa, significantly increased catalase, superoxide dismutase and reduced glutathione levels, and significantly suppressed the increases of plasma cytokines (TNF-α and IL-1β) observed in the Aa group. In conclusion, O. ficus-indica ACE has significant anti-inflammatory properties by restoring oxidative balance, indicating that it could be a potential source of therapeutic agents for inflammatory diseases, particularly UC. [ABSTRACT FROM AUTHOR]

Purpose: Chronic granulomatous disease (CGD) is an inherited immunodeficiency caused by pathogenic variants of genes encoding the enzyme complex NADPH oxidase. In countries where tuberculosis (TB) is endemic and the Bacillus Calmette–Guérin (BCG) vaccine is routinely administered, mycobacteria are major disease-causing pathogens in CGD. However, information on the clinical evolution and treatment of mycobacterial diseases in patients with CGD is limited. The present study describes the adverse reactions to BCG and TB in Mexican patients with CGD. Methods: Patients with CGD who were evaluated at the Immunodeficiency Laboratory of the National Institute of Pediatrics between 2013 and 2024 were included. Medical records were reviewed to determine the clinical course and treatment of adverse reactions to BCG and TB disease. Results: A total of 79 patients with CGD were included in this study. Adverse reactions to BCG were reported in 55 (72%) of 76 patients who received the vaccine. Tuberculosis was diagnosed in 19 (24%) patients. Relapse was documented in three (10%) of 31 patients with BGC-osis and six (32%) of 19 patients with TB, despite antituberculosis treatment. There was no difference in the frequency of BCG and TB disease between patients with pathogenic variants of the X-linked CYBB gene versus recessive variants. Conclusions: This report highlights the importance of considering TB in endemic areas and BCG complications in children with CGD to enable appropriate diagnostic and therapeutic approaches to improve prognosis and reduce the risk of relapse. [ABSTRACT FROM AUTHOR]

Background: The present study investigated the function of G protein-coupled receptor kinase 2 (GRK2) in acute liver injury (ALI) by cisplatin, and investigated the protective effect of pharmacological inhibition of GRK2. Methods: ALI models were generated in global adult hemizygous (ALI-Grk2±) mice and wild-type (WT) mice. Liver biochemistry parameters and histopathology were used to evaluate the severity of ALI and the protective effect of pharmacological inhibition of GRK2. GRK2-siRNA was used to knock down the expression of GRK2 in AML12 cells in vitro. Results: ALI model mice exhibited increased blood levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and abnormal liver pathology accompanied by imbalanced L-glutathione (GSH) levels. Cisplatin administration upregulated GKR2, p-GRK2 and NADPH oxidase 4 (NOX4) expression in the liver tissues of ALI model mice. Compared to WT mice injected with cisplatin, Grk2± mice that received cisplatin showed significant improvements in liver function and pathological performance, decreased NOX4 levels, reduced endoplasmic reticulum (ER) stress, and diminished liver cell apoptosis. In vitro, the transfection of AML12 cells with siRNA significantly reduced NOX4 expression and inhibited cisplatin-induced reactive oxygen species production, ER stress (increased levels of GRP94, GRP78, p-elF2α and CHOP) and apoptotic death. Moreover, pharmacological treatment with drugs that inhibit GRK2 (CP-25 or paroxetine) significantly ameliorated cisplatin-induced ALI by improving liver pathological manifestations, inhibiting oxidative stress and ER stress, and reducing liver cell apoptosis. Similar results were observed in vitro. Conclusions: GRK2 mediates the development of cisplatin-induced ALI by modulating NOX4 and ER stress. Pharmacological inhibition of GRK2 with CP-25 or paroxetine effectively alleviated ALI. GRK2 can be used as a potential target for the prevention and treatment of liver injury. [ABSTRACT FROM AUTHOR]

Preeclampsia (PE) is associated with increased angiotensin II sensitivity and poor neurological outcomes marked by temporal loss of neural control of blood pressure. Yet the role of centrally expressed angiotensin II type 1 receptor (AT1R) within the paraventricular nucleus of the hypothalamus (PVN) in the PE model is not understood. In a PE rat model with reduced placental perfusion pressure (RUPP) induced on gestational day 14 (GD14), the PVN expression and cellular localization of AT1R were assessed using immunofluorescence and western blotting. The sensitivity of RUPP to acute angiotensin II infusion was assessed. AT1R was antagonized by losartan (100 µg/kg/day) for 5 days intracerebroventricularly (ICV). Hemodynamic data and samples were collected on GD19 for further analysis. RUPP upregulated (p < 0.05) mRNA and protein of AT1R within the PVN and lowered (p < 0.05) circulating angiotensin II in rats. RUPP increased neural and microglial activation. Cellular localization assessment revealed that AT1R was primarily expressed in neurons and slightly in microglia and astrocytes. Infusion of 100 ng/kg as bolus increased the mean arterial pressure (MAP in mmHg) in both RUPP and Sham. ICV losartan infusion attenuated RUPP-increased MAP (113.6 ± 6.22 in RUPP vs. 92.16 ± 5.30 in RUPP + Los, p = 0.021) and the expression of nuclear transcription factor NF-κB, tyrosine hydroxylase (TH), NADPH oxidase 4 (NOX4) and reactive oxygen species (ROS) in the PVN. Our data suggest that centrally expressed AT1R, within the PVN, contributes to placental ischemia–induced hypertension in RUPP rats highlighting its therapeutic potential in PE. [ABSTRACT FROM AUTHOR]

Cold atmospheric plasma (CAP) is a promising complement to tissue repair and regenerative medicine approaches. CAP has therapeutic potential in infected cutaneous wounds by mechanisms which remain enigmatic. Here, CAP is shown to activate phagocyte NADPH oxidase complex NOX2. CAP induced increased intracellular reactive oxygen species, alleviated by NOX2 inhibitors. Genetic and pharmacological inhibitions of NOX2 in macrophages and bioengineered skin infected with Staphylococcus aureus and treated with CAP reduced intracellular oxidants and increased bacterial survival. CAP triggered Rac activation and phosphorylation of p40phox and p47phox required for NOX2 assembly and activity. Furthermore, CAP induced collagen I expression by fibroblasts. Infection and healing kinetics showed that murine skin wounds infected with S. aureus and treated with CAP are characterized by decreased bacterial burden, increased length of neoepidermis and extracellular matrix formation. Collectively, our findings identify mechanisms triggered by CAP that subdue infection and result in enhanced repair following skin injury. [ABSTRACT FROM AUTHOR]

The stress-protective effect of melatonin (N-acetyl-5-methoxytryptamine) on plant cells is mediated by key signaling mediators, in particular calcium ions and reactive oxygen species (ROS). However, the links between changes in calcium and redox homeostasis and the formation of adaptive responses of cultivated cereals (including wheat) to the action of high temperatures have not yet been studied. In the present study, we investigated the possible involvement of ROS and calcium ions as signaling mediators in developing heat resistance in wheat (Triticum aestivum L.) seedlings and activating their antioxidant system. Treatment of 3-day-old etiolated seedlings with melatonin solutions at concentrations 0.01–10 µM increased their survival after exposure to 45 °C for 10 min. The most significant stress-protective effect was exerted by melatonin treatment at 1 µM concentration. Under the influence of melatonin, a transient enhancement of superoxide anion radical (O2•–) generation and an increase in hydrogen peroxide content were observed in roots, with a maximum at 1 h. Four hours after treatment with melatonin, the activity of catalase and guaiacol peroxidase increased in roots, while the activity of superoxide dismutase did not change significantly. After exposure to 45 °C, the activity of catalase and guaiacol peroxidase was higher in the roots of melatonin-treated wheat seedlings, and the indices of ROS generation, content of the lipid peroxidation product malonic dialdehyde, and cell membrane damage were lower than in control seedlings. Melatonin-induced changes in root ROS generation and antioxidant enzyme activities were eliminated by pretreatment with the hydrogen peroxide scavenger dimethylthiourea (DMTU), NADPH oxidase inhibitor imidazole, and calcium antagonists (the extracellular calcium chelator EGTA and phospholipase C inhibitor neomycin). Treatment with DMTU, imidazole, EGTA, and neomycin also abolished the melatonin-induced increase in survival of wheat seedlings after heat stress. The role of calcium ions and ROS, generated with the participation of NADPH oxidase, as signaling mediators in the melatonin-induced antioxidant system and heat stress resistance of wheat seedlings have been demonstrated. [ABSTRACT FROM AUTHOR]

Phosphate homeostasis is vital for many biological processes and disruptions in circulating levels can be detrimental. While the mechanisms behind FGF23 regulation have been regularly studied, the role of extracellular phosphate sensing and its impact on fibroblast growth factor 23 (FGF23) expression remains unclear. This study aimed to investigate the involvement of reactive oxygen species (ROS), silent information regulator 1 (SIRT1), and Hairy and Enhancer of Split-1 (HES1) in regulating FGF23 in FGF23 expressing MC3T3-E1 cells. MC3T3-E1 cells treated with β-glycerophosphate (BGP) resulted in increased Fgf23 expression. Inhibition of ROS formation by inhibition of NADPH oxidase, which is essential for ROS production, did not affect this response to BGP, suggesting ROS is not involved in this process. Moreover, treatment with tert-butyl hydroperoxide (TBHP), a ROS-inducing agent, did not increase Fgf23 expression. This suggests that ROS machinery is not involved in FGF23 stimulation as previously suggested. Nonetheless, inhibition of SIRT1 using Ex527 eliminated the Fgf23 response to BGP, indicating its involvement in FGF23 regulation after BGP treatment. Indeed, activation of SIRT1 using SRT1720 increased Fgf23 expression. Moreover, transcription factor Hes1 was upregulated by BGP treatment, which was diminished when cells were treated with Ex527 implying it is also regulated through SIRT1. These findings suggest the existence of an upstream SIRT1-HES1 axis in the regulation of FGF23 by phosphate, though we were unable to find a role for ROS in this process. Further research should provide insights into phosphate homeostasis and potential therapeutic targets for phosphate-related disorders. [ABSTRACT FROM AUTHOR]

Levamisole is an anthelmintic drug restricted to veterinary use but is currently detected as the most widely used cocaine cutting agent in European countries. Levamisole-adulterated cocaine has been linked to acute kidney injury, marked by a decrease in glomerular filtration rate, which involves reduced renal blood flow, but data on the alteration of renovascular response produced by levamisole are scarce. Renal arteries were isolated from healthy rabbits and used for isometric tension recording in organ baths and protein analysis. We provide evidence that depending on its concentration, levamisole modulates renovascular tone by acting as a non-selective α-adrenergic receptor blocker and down-regulates α1-adrenoceptor expression. Furthermore, levamisole impairs the endothelium-dependent relaxation induced by acetylcholine without modifying endothelial nitric oxide synthase (eNOS) expression. However, exposure to superoxide dismutase (SOD) partially prevents the impairment of ACh-induced relaxation by levamisole. This response is consistent with a down-regulation of SOD1 and an up-regulation of NADPH oxidase 4 (Nox4), suggesting that endothelial NO loss is due to increased local oxidative stress. Our findings demonstrate that levamisole can interfere with renal blood flow and the coordinated response to a vasodilator stimulus, which could worsen the deleterious consequences of cocaine use. EFS electric field stimulation, NA noradrenaline, AR adrenergic receptor, IP3 inositol 1, 4, 5-trisphosphate, cAMP cyclic adenosine monophosphate, mAChR muscarinic acetylcholine receptor, eNOS endothelial nitric oxide synthase, sGC soluble guanylyl cyclase, SOD superoxide dismutase, NOX4 NAPH oxidase 4 [ABSTRACT FROM AUTHOR]

Lasia spinosa (L. spinosa) is widely used in Asian countries for treating various diseases and as a vegetable, yet its bioactive properties remain under-researched. It is traditionally utilized in Ayurveda and the AYUSH system of medicine for its medicinal properties, and commonly used to treat digestive disorders, respiratory issues, and inflammatory conditions. This study aims to identify the phytochemicals in L. spinosa leaves and fruit extracts and evaluate their biological activities. Phytochemicals in methanol extracts of L. spinosa fruits and leaves were identified by GC-MS analysis. Antioxidant and cytotoxic activities were assessed using the DPPH free radical and nitric oxide (NO) scavenging assay and brine shrimp lethality test. Antibacterial activity was evaluated against Shigella boydii, Shigella flexneri, Streptococcus iniae, and Streptococcus dysgalactiae, while antifungal properties were tested against Cercospora beticola and Rhizoctonia solani. Molecular docking was conducted to predict the effectiveness of L. spinosa phytochemicals against NADPH oxidase and the Shigella effector OspG. Nine compounds were detected from both extracts. The methanol leaves extract exhibited superior antioxidant activity compared to the fruit extract, with IC50 values of 111.81 ± 8.99 µg/ml and 174.81 ± 4.86 µg/ml, respectively, as determined by the DPPH scavenging assay. The nitric oxide (NO) scavenging assay also revealed higher potency in the leaves extract (IC50 = 138.59 ± 1.50 µg/ml) compared to the fruit extract (IC50 = 196.47 ± 1.72 µg/ml). Both extracts showed significant antimicrobial activity against all tested microorganisms. In silico studies indicated notable inhibitory activity of all phytochemicals against the target proteins, with Linoelaidic acid and 9-Octadecenamide, (Z)- exhibiting the highest activity against NADPH oxidase (PDB: 2cdu) and Shigella flexneri OspG effector kinase (PDB: 4bvu), respectively. These findings suggest that L. spinosa has potent antioxidant and antimicrobial activities. Compounds from this plant could serve as lead compounds for developing antioxidant and antibacterial agents. However, molecular studies should be addressed. [ABSTRACT FROM AUTHOR]

The spatiotemporal regulation of inflammasome activation remains unclear. To examine the mechanism underlying the assembly and regulation of the inflammasome response, here we perform an immunoprecipitation-mass spectrometry analysis of apoptosis-associated speck-like protein containing a CARD (ASC) and identify NCF4/1/2 as ASC-binding proteins. Reduced NCF4 expression is associated with colorectal cancer development and decreased five-year survival rate in patients with colorectal cancer. NCF4 cooperates with NCF1 and NCF2 to promote NLRP3 and AIM2 inflammasome activation. Mechanistically, NCF4 phosphorylation and puncta distribution switches from the NADPH complex to the perinuclear region, mediating ASC oligomerization, speck formation and inflammasome activation. NCF4 functions as a sensor of ROS levels, to establish a balance between ROS production and inflammasome activation. NCF4 deficiency causes severe colorectal cancer in mice, increases transit-amplifying and precancerous cells, reduces the frequency and activation of CD8+ T and NK cells, and impairs the inflammasome-IL-18-IFN-γ axis during the early phase of colorectal tumorigenesis. Our study implicates NCF4 in determining the spatial positioning of inflammasome assembly and contributing to inflammasome-mediated anti-tumor responses. The NADPH oxidase 2 (NOX2) complex is a main reactive oxygen species (ROS) source during inflammation. Here the authors report that NCF4, a subunit of the NOX2 complex, acts a sensor of ROS levels and regulates NLRP3 and AIM2 inflammasome activation, associated with attenuated colorectal cancer progression. [ABSTRACT FROM AUTHOR]

Neutrophil granulocytes play a crucial role in host defense against invading pathogens and in inflammatory diseases. The aim of this study was to elucidate membrane potential dynamics during the initial phase of neutrophil activation and its relation to migration and production of reactive oxygen species (ROS). We performed ROS production measurements of neutrophils from healthy C57BL/6J mice after TNFα-priming and/or C5a stimulation. The actin cytoskeleton was visualized with fluorescence microscopy. Furthermore, we combined migration assays and measurements of membrane potential dynamics after stimulating unprimed and/or TNFα-primed neutrophils with C5a. We show that C5a has a concentration-dependent effect on ROS production and chemokinetic migration. Chemokinetic migration and chemotaxis are impaired at C5a concentrations that induce ROS production. The actin cytoskeleton of unstimulated and of ROS-producing neutrophils is not distributed in a polarized way. Inhibition of the phagocytic NADPH oxidase NOX2 with diphenyleneiodonium (DPI) leads to a polarized distribution of the actin cytoskeleton and rescues chemokinetic migration of primed and C5a-stimulated neutrophils. Moreover, C5a evokes a pronounced depolarization of the cell membrane potential by 86.6 ± 4.2 mV starting from a resting membrane potential of -74.3 ± 0.7 mV. The C5a-induced depolarization occurs almost instantaneously (within less than one minute) in contrast to the more gradually developing depolarization induced by PMA (lag time of 3—4 min). This initial depolarization is accompanied by a decrease of the migration velocity. Collectively, our results show that stimulation with C5a evokes parallel changes in membrane potential dynamics, neutrophil ROS production and motility. Notably, the amplitude of membrane potential dynamics is comparable to that of excitable cells. [ABSTRACT FROM AUTHOR]

Minocycline, a repurposed approved medication, shows promise in treating neurodegeneration. However, the specific pathways targeted by minocycline remain unclear despite the identification of molecular targets. This study explores minocycline's potential protective effects against TNF-α-mediated neuronal death in PC12 cells, with a focus on unraveling its interactions with key molecular targets. The study begins by exploring minocycline's protective role against TNF-α-mediated neuronal death in PC12 cells, showcasing a substantial reduction in cleaved caspase-3 expression, DNA fragmentation, and intracellular ROS levels following minocycline pretreatment. Subsequently, a comprehensive analysis utilizing pull-down assays, computational docking, mutation analysis, molecular dynamics simulations, and free energy calculations is conducted to elucidate the direct interaction between minocycline and p47phox—the organizer subunit of NADPH oxidase-2 (NOX2) complex. Computational insights, including a literature survey and analysis of key amino acid residues, reveal a potential binding site for minocycline around Trp193 and Cys196. In silico substitutions of Trp193 and Cys196 further confirm their importance in binding with minocycline. These integrated findings underscore minocycline's protective mechanisms, linking its direct interaction with p47phox to the modulation of NOX2 activity and attenuation of NOX-derived ROS generation. Minocycline demonstrates protective effects against TNF-α-induced PC12 cell death, potentially linked to its direct interaction with p47phox. This interaction leads to a reduction in NOX2 complex assembly, ultimately attenuating NOX-derived ROS generation. These findings hold significance for researchers exploring neuroprotection and the development of p47phox inhibitors. [ABSTRACT FROM AUTHOR]

NADPH oxidase 5 (NOX5) catalyzes the production of superoxide free radicals and regulates physiological processes from sperm motility to cardiac rhythm. Overexpression of NOX5 leads to cancers, diabetes, and cardiovascular diseases. NOX5 is activated by intracellular calcium signaling, but the underlying molecular mechanism of which — in particular, how calcium triggers electron transfer from NADPH to FAD — is still unclear. Here we capture motions of full-length human NOX5 upon calcium binding using single-particle cryogenic electron microscopy (cryo-EM). By combining biochemistry, mutagenesis analyses, and molecular dynamics (MD) simulations, we decode the molecular basis of NOX5 activation and electron transfer. We find that calcium binding to the EF-hand domain increases NADPH dynamics, permitting electron transfer between NADPH and FAD and superoxide production. Our structural findings also uncover a zinc-binding motif that is important for NOX5 stability and enzymatic activity, revealing modulation mechanisms of reactive oxygen species (ROS) production. NADPH oxidase 5 (NOX5) is activated by Ca2+ signaling, catalyzing superoxide production by transferring electrons from intracellular NADPH to extracellular oxygen. Here the authors uncover the molecular basis of NOX5 activation and electron transfer. [ABSTRACT FROM AUTHOR]

Plant glutamate receptor-like channels (GLRs) play important roles in plant development, immune response, defense signaling and Nitric oxide (NO) production. However, their involvement in abiotic stress responses, particularly in regulating Reactive Oxygen Species (ROS), is not well understood. This study aimed to investigate GLR-mediated NO production on ROS regulation in salt-stressed cells. To achieve this, Arabidopsis thaliana Columbia (Col-0) were treated with NaCl, glutamate antagonists [(DNQX (6,7-dinitroquinoxaline-2,3-dione and AP-5(D-2-amino-5-phosphono pentanoic acid)], and NO scavenger [cPTIO (2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt)]. Salt-stressed plants in combination with DNQX and AP-5 have exhibited higher increase in lipid peroxidation (TBARS), hydrogen peroxide (H2O2) and superoxide radical (O−2) contents as compared to solely NaCl-treated plants. Furthermore, NO and total glutathione contents, and S-nitrosoglutathione reductase (GSNOR) activity decreased with these treatments. AP-5 and DNQX increased the activities of NADPH oxidase (NOX), catalase (CAT), peroxidase (POX), cell wall peroxidase (CWPOX) in salt-stressed Arabidopsis leaves. However, their activities (except NOX) were significantly inhibited by cPTIO. Conversely, the combination of NaCl and GLR antagonists, NO scavenger decreased the activities of ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione reductase (GR), dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) resulting in elevated GSSG levels, a low GSH/GSSG ratio, impaired ROS scavenging, excessive ROS accumulation and cell membrane damage. The findings of this study provide evidence that GLR-mediated NO plays a crucial role in improvement of the tolerance of Arabidopsis plants to salt-induced oxidative stress. It helps to maintain cellular redox homeostasis by reducing ROS accumulation and increasing the activity of SOD, GSNOR, and the ASC-GSH cycle enzymes. [ABSTRACT FROM AUTHOR]

Drought is a major limiting factor for rice (Oryza sativa L.) production globally, and a cost-effective seed priming technique using bio-elicitors has been found to have stress mitigating effects. Till date, mostly phytohormones have been preferred as bio-elicitors, but the present study is a novel attempt to demonstrate the favorable role of micronutrients-phytohormone cocktail, i.e., iron (Fe), zinc (Zn), and methyl jasmonate (MJ) via seed priming method in mitigating the deleterious impacts of drought stress through physio-biochemical and molecular manifestations. The effect of cocktail/priming was studied on the relative water content, chlorophyll a/b and carotenoid contents, proline content, abscisic acid (ABA) content, and on the activities of ascorbate peroxidase (APX), superoxide dismutase (SOD), NADPH oxidase (Nox), and catalase (CAT). The expressions of drought-responsive genes OsZn-SOD, OsFe-SOD, and Nox1 were found to be modulated under drought stress in contrasting rice genotypes -N-22 (Nagina-22, drought-tolerant) and PS-5 (Pusa Sugandh-5, drought-sensitive). A progressive rise in carotenoids (10–19%), ABA (18–50%), proline (60–80%), activities of SOD (27–62%), APX (46–61%), CAT (50–80%), Nox (16–30%), and upregulated (0.9–1.6-fold) expressions of OsZn-SOD, OsFe-SOD, and Nox1 genes were found in the primed plants under drought condition. This cocktail would serve as a potential supplement in modern agricultural practices utilizing seed priming technique to mitigate drought stress-induced oxidative burst in food crops. [ABSTRACT FROM AUTHOR]

Neuroinflammation mediated by microglia and oxidative stress play pivotal roles in the development of chronic temporal lobe epilepsy (TLE). We postulated that kainic acid (KA)-Induced status epilepticus triggers microglia-dependent inflammation, leading to neuronal damage, a lowered seizure threshold, and the emergence of spontaneous recurrent seizures (SRS). Extensive evidence from our laboratory suggests that dextromethorphan (DM), even in ultra-low doses, has anti-inflammatory and neuroprotective effects in many animal models of neurodegenerative disease. Our results showed that administration of DM (10 ng/kg per day; subcutaneously via osmotic minipump for 4 weeks) significantly mitigated the residual effects of KA, including the frequency of SRS and seizure susceptibility. In addition, DM-treated rats showed improved cognitive function and reduced hippocampal neuronal loss. We found suppressed microglial activation-mediated neuroinflammation and decreased expression of hippocampal gp91phox and p47phox proteins in KA-induced chronic TLE rats. Notably, even after discontinuation of DM treatment, ultra-low doses of DM continued to confer long-term anti-seizure and neuroprotective effects, which were attributed to the inhibition of microglial NADPH oxidase 2 as revealed by mechanistic studies. [ABSTRACT FROM AUTHOR]

Levels and chemical species of reactive oxygen/nitrogen species (ROS/RNS) determine oxidative eustress and distress. Abundance of uptake pathways and high oxygen consumption for ATP-dependent transport makes the renal proximal tubule particularly susceptible to cadmium (Cd2+)-induced oxidative stress by targeting ROS/RNS generation or antioxidant defence mechanisms, such as superoxide dismutase (SOD) or H2O2-metabolizing catalase (CAT). Though ROS/RNS are well-evidenced, the role of distinct ROS profiles in Cd2+ concentration-dependent toxicity is not clear. In renal cells, Cd2+ (10–50 µM) oxidized dihydrorhodamine 123, reaching a maximum at 2–3 h. Increases (up to fourfold) in lipid peroxidation by TBARS assay and H2O2 by Amplex Red were evident within 30 min. ROS and loss in cell viability by MTT assay with 50 µM Cd2+ could not be fully reversed by SOD mimetics Tempol and MnTBAP nor by SOD1 overexpression, whereas CAT expression and α-tocopherol were effective. SOD and CAT activities were attenuated below controls only with >6 h 50 µM Cd2+, yet augmented by up to 1.5- and 1.2-fold, respectively, by 10 µM Cd2+. Moreover, 10 µM, but not 25–50 µM Cd2+, caused 1.7-fold increase in superoxide anion (O2•−), detected by dihydroethidium, paralled by loss in cell viability, that was abolished by Tempol, MnTBAP, α-tocopherol and SOD1 or CAT overexpression. H2O2-generating NADPH oxidase 4 (NOX4) was attenuated by ~50% with 10 µM Cd2+ at 3 h compared to upregulation by 50 µM Cd2+ (~1.4-fold, 30 min), which was sustained for 24 h. In summary, O2•− predominates with low–moderate Cd2+, driving an adaptive response, whereas oxidative stress by elevated H2O2 at high Cd2+ triggers cell death signaling pathways. Highlights Different levels of reactive oxygen species are generated, depending on cadmium concentration. Superoxide anion predominates and H2O2 is suppressed with low cadmium representing oxidative eustress. High cadmium fosters H2O2 by inhibiting catalase and increasing NOX4 leading to oxidative distress. Superoxide dismutase mimetics and overexpression were less effective with high versus low cadmium. Oxidative stress profile could dictate downstream signalling pathways. [ABSTRACT FROM AUTHOR]

The therapeutic benefit of doxorubicin has led to a tremendous improvement in treating cancer. However, it has been associated with cardiotoxicity, renal, and hepatic toxicities, among others. Hence, the continuous search for natural scavengers of DOX-induced toxicity remains imperative. This study evaluated the hepatoprotective and nephroprotective effects of ethanol extracts of Urtica dioica (UD) leaves on doxorubicin-induced oxidative stress. This study comprised 5 groups: control, doxorubicin (DOX: 15 mg/kg), UD-treated group (DOX + 300 mg/kg), a second UD-treated group (DOX + 600 mg/kg), and UD-treated group (600 mg/kg alone). The in vitro antioxidant potential of UD was assayed with FRAP and DPPH, and GCMS-identified UD phytoconstituents were docked against NADPH oxidase (2CDU) and nitric oxide synthase (2FLQ) using molecular docking tools such as Discovery Studio, Open Babel, and PyRX. UD had a concentration-dependent FRAP better than BHT and a DPPH scavenging activity of IC50 265.96 g/ml. The DOX group had hepatic and renal alteration that was evident in the significant (p < 0.05) elevation of hepatic (AST and ALT) and renal (BUN, creatinine, Na+) markers with reduced antioxidant markers (GPx, CAT, GSH). The CRP level of the DOX group was also significantly (p < 0.05) higher than that of the control group. The UD-treated group (DOX + 300 mg/kg) showed a significant (p < 0.05) reduction in the CRP, hepatic, and renal biomarkers, with a significant improvement in the activities of the antioxidant markers. The selected UD compounds showed good binding affinities against 2CDU and 2FLQ. Beta-Bissabolene (-9.2 and -8.0 kg/mol) and Alpha-Terpineol (-7.7 and -7.0 kg/mol) have higher binding affinities and good hydrogen interactions with 2FLQ and 2CDU, with acceptable drug-likeness properties. Urtica dioica extract and its compounds showed great potential for preventing DOX-induced hepatotoxicity and nephrotoxicity through modulation and reduction of biomarkers of cellular toxicity and enhancement of endogenous antioxidant enzymes. Beta-Bissabolene and Alpha-Terpineol from UD, through molecular docking, showed to be very potent in preventing ROS-mediated oxidative stress; hence, they may be adopted as toxicity-preventive candidates in doxorubicin treatments. [ABSTRACT FROM AUTHOR]

Tumor cells must rewire nucleotide synthesis to satisfy the demands of unbridled proliferation. Meanwhile, they exhibit augmented reactive oxygen species (ROS) production which paradoxically damages DNA and free deoxy-ribonucleoside triphosphates (dNTPs). How these metabolic processes are integrated to fuel tumorigenesis remains to be investigated. MYC family oncoproteins coordinate nucleotide synthesis and ROS generation to drive the development of numerous cancers. We herein perform a Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based functional screen targeting metabolic genes and identified nudix hydrolase 1 (NUDT1) as a MYC-driven dependency. Mechanistically, MYC orchestrates the balance of two metabolic pathways that act in parallel, the NADPH oxidase 4 (NOX4)-ROS pathway and the Polo like kinase 1 (PLK1)-NUDT1 nucleotide-sanitizing pathway. We describe LC-1-40 as a potent, on-target degrader that depletes NUDT1 in vivo. Administration of LC-1-40 elicits excessive nucleotide oxidation, cytotoxicity and therapeutic responses in patient-derived xenografts. Thus, pharmacological targeting of NUDT1 represents an actionable MYC-driven metabolic liability. MYC oncogene promotes tumourigenesis by coordinating cancer cell proliferation with metabolic adaptation to the consequent excessive oxidative stress. Here, the authors show that nudix hydrolase 1 (NUDT1) is a MYC-driven metabolic vulnerability and generate a NUDT1 protein degrader to treat preclinical MYC-associated cancer. [ABSTRACT FROM AUTHOR]

Ulcerative colitis is an inflammatory bowel disease with a complex aetiology characterised by abnormal immune responses and oxidative stress–induced tissue injury. Inflammatory cells play an important role in the progression of this pathology through the overproduction of reactive oxygen species (ROS) from various sources including the NADPH oxidases (NOXs). The aim of this study was to investigate the preventive effect of apocynin, a natural antioxidant molecule and a selective inhibitor of NOXs, on acetic acid (AA)-induced ulcerative colitis in rats. Our results first confirmed that apocynin has a high free radical scavenging capacity as well as a potent iron chelating ability. Oral pretreatment of rats with apocynin (200 mg/kg and 400 mg/kg) for 7 days prior to AA-induced colitis suppressed the increase in pro-oxidant markers in colonic homogenates and preserved colonic cytoarchitecture from acetic acid–induced damage. Oral administration of apocynin (200 mg/kg and 400 mg/kg) also reduced several systemic inflammatory markers such as alkaline phosphatase, iron, pro-inflammatory cytokines, C-reactive protein and myeloperoxidase. This study shows that apocynin protects rats from acetic acid–induced colonic inflammation and suggests that apocynin may have a promising beneficial effect in the prevention of ulcerative colitis. [ABSTRACT FROM AUTHOR]

Despite the plant health-promoting effects of plant microbiota, these assemblages also comprise potentially detrimental microbes. How plant immunity controls its microbiota to promote plant health under these conditions remains largely unknown. We find that commensal bacteria isolated from healthy Arabidopsis plants trigger diverse patterns of reactive oxygen species (ROS) production dependent on the immune receptors and completely on the NADPH oxidase RBOHD that selectively inhibited specific commensals, notably Xanthomonas L148. Through random mutagenesis, we find that L148 gspE, encoding a type II secretion system (T2SS) component, is required for the damaging effects of Xanthomonas L148 on rbohD mutant plants. In planta bacterial transcriptomics reveals that RBOHD suppresses most T2SS gene expression including gspE. L148 colonization protected plants against a bacterial pathogen, when gspE was inhibited by ROS or mutation. Thus, a negative feedback loop between Arabidopsis ROS and the bacterial T2SS tames a potentially detrimental leaf commensal and turns it into a microbe beneficial to the host. The plant immune output reactive oxygen species tames a detrimental bacterial commensal from native microbiota by suppressing a bacterial secretion system, allowing the co-existence and turning it into a beneficial bacterium to the host. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) act as a group of signaling molecules in rice functioning in regulation of development and stress responses. Respiratory burst oxidase homologues (Rbohs) are key enzymes in generation of ROS. However, the role of the nine Rboh family members was not fully understood in rice multiple disease resistance and yield traits. In this study, we constructed mutants of each Rboh genes and detected their requirement in rice multiple disease resistance and yield traits. Our results revealed that mutations of five Rboh genes (RbohA, RbohB, RbohE, RbohH, and RbohI) lead to compromised rice blast disease resistance in a disease nursery and lab conditions; mutations of five Rbohs (RbohA, RbohB, RbohC, RbohE, and RbohH) result in suppressed rice sheath blight resistance in a disease nursery and lab conditions; mutations of six Rbohs (RbohA, RbohB, RbohC, RbohE, RbohH and RbohI) lead to decreased rice leaf blight resistance in a paddy yard and ROS production induced by PAMPs and pathogen. Moreover, all Rboh genes participate in the regulation of rice yield traits, for all rboh mutants display one or more compromised yield traits, such as panicle number, grain number per panicle, seed setting rate, and grain weight, resulting in reduced yield per plant except rbohb and rbohf. Our results identified the Rboh family members involved in the regulation of rice resistance against multiple pathogens that caused the most serious diseases worldwide and provide theoretical supporting for breeding application of these Rbohs to coordinate rice disease resistance and yield traits. [ABSTRACT FROM AUTHOR]

Oxidative stress can be a series burden on human health and may lead to many chronic diseases such as diabetes and neurological disorders. The use of natural products to scavenge the reactive oxygen species has attracted the attention of many researchers, to safely manage these conditions with fewer side effects, in available and cost-effective ways. The current study aimed at the isolation and structure elucidation of sweroside from Schenkia spicata (Gentianaceae) and the evaluation of its antioxidant, antidiabetic, neuroprotective, and enzyme inhibitory potential via in vitro and in silico studies. The antioxidant potential was evaluated by a variety of assays as ABTS, CUPRAC and FRAP, showing values of 0.34 ± 0.08, 21.14 ± 0.43, and 12.32 ± 0.20 mg TE/g, respectively, while demonstrating 0.75 ± 0.03 mmol TE/g for phosphomolybdenum (PBD) assay. Acetylcholinestrase (AChE), butyrylcholinesterase (BChE) and tyrosinase inhibitory activities were used to evaluate the neuroprotective effect, while the antidiabetic potential was evaluated by measuring α-amylase and glucosidase inhibitory activities. Results revealed that sweroside showed antioxidant and inhibitory effects on the enzymes tested with the exception of AChE. It demonstrated good tyrosinase inhibitory ability with 55.06 ± 1.85 mg Kojic acid equivalent /g. Regarding the antidiabetic ability, the compound displayed both amylase and glucosidase (0.10 ± 0.01 and 1.54 ± 0.01 mmol Acarbose equivalent/g, respectively) inhibitory activities. Molecular docking studies of sweroside on the active sites of the aforementioned enzymes in addition to NADPH oxidase were performed using Discovery Studio 4.1 software. Results revealed good binding affinities of sweroside to these enzymes mainly through hydrogen bonds and van der Waals interactions. Sweroside can be an important antioxidant and enzyme inhibitory supplement, yet further in vivo and clinical studies are required. [ABSTRACT FROM AUTHOR]

A growing concern of cardiotoxicity induced by PI3K inhibitors has raised the requirements to evaluate the structure-cardiotoxicity relationship (SCR) in the development process of novel inhibitors. Based on three bioisosteric 7-azaindazole-based candidate inhibitors namely FD269, FD268 and FD274 that give same order of inhibitory concentration 50% (IC50) magnitude against PI3Ks, in this work, we proposed to systematically evaluate the SCR of 7-azaindazole-based PI3K inhibitors designed by bioisosteric approach. The 24-h lethal concentrations 50% (LC50) of FD269, FD268 and FD274 against zebrafish embryos were 0.35, 4.82 and above 50 μM (not detected), respectively. Determination of the heart rate, pericardial and yolk-sac areas and vascular malformation confirmed the remarkable reduction in the cardiotoxicity of from FD269 to FD268 and to FD274. The IC50s of all three compounds against the hERG channel were tested on the CHO cell line that constitutively expressing hERG channel, which were all higher than 20 μM. The transcriptomic analysis revealed that FD269 and FD268 induced the up-regulation of noxo1b, which encodes a subunit of an NADPH oxidase evoking the oxidative stress. Furthermore, immunohistochemistry tests confirmed the structure-dependent attenuation of the overproduction of ROS and cardiac apoptosis. Our results verified the feasibility of bioisosteric replacement to attenuate the cardiotoxicity of 7-azaindazole-based PI3K inhibitors, suggesting that the screening for PI3K inhibitors with both high potency and low cardiotoxicity from bioisosteres would be a beneficial trial. [ABSTRACT FROM AUTHOR]

Objectives: Microsclerotia (MS), anti-stress structures produced by many filamentous fungi, have been proven to be a great substitute for conidia in the production of insecticides within entomogenous fungi. NADPH oxidase (Nox) is a highly conserved ROS-response protein family that is widespread in eukaryotes and plays distinct roles in environmental fitness among various filamentous fungi. However, it is not clear whether the formation of MS and pathogenicity in entomogenous fungi is regulated by the Nox inside. In this study, we reported the presence of NADPH oxidase homologs in a great potential biocontrol fungus, Metarhizium rileyi, and further showed multiple biological functions. Results: Three Nox homologous genes in M. rileyi showed high expression throughout the entire process of MS formation. Targeted deletion of MrNoxA, MrNoxB and MrNoxR all led to a decrease in MS yield and impaired morphology. Moreover, the anti-adversity assay showed that they are indispensable for growth, osmotic pressure and oxidative stress regulation in Metarhizium rileyi. Most importantly, △MrNoxR and △MrNoxA but not △MrNoxB showed a dramatic reduction in virulence via inoculation. The normality of appressoria might be unaffected in mutants since there are no striking differences in virulence compared with WT by topical injections. Conclusion: Our results revealed that NADPH oxidase plays important roles in growth regulation, MS formation and pathogenicity in M. rileyi, perhaps in the ROS response and hyphal polarity. [ABSTRACT FROM AUTHOR]

Neutrophils release decondensed nuclear chromatin or neutrophil extracellular trap (NETs) in response to a large number of different physiological stimuli in order to protect the host from the pathogens. However, as it has been recently established, NETs play an important role in the pathogenesis of autoimmune, inflammatory, and oncological diseases. In this regard, understanding molecular mechanisms underlying the formation of NETs and leading, as a rule, to the death of neutrophils (NETosis) is extremely important to provide a control of aberrant chromatin release. Mitogen-activated protein kinases (MAP kinases) are involved in diverse cellular functions, such as oxidative burst, chemotaxis, degranulation, adhesion, and apoptosis; however, their role in NETosis was not sufficiently studied. Three families of MAP kinases were described in human neutrophils, including p38, ERK1/2, and JNK. In our work, the involvement of p38, ERK1/2, as well as protein kinase B Akt1/2, in the oxidative burst and NETosis was studied using an inhibitory analysis. We demonstrated that p38 MAP kinase and protein kinase B Akt1/2 are activated upon stimulation of the oxidative burst and NETosis by calcium ionophore ionomycin. At the same time, these kinases are not involved in the oxidative burst induced by diacylglycerol mimetic phorbol 12-myristate 13-acetate (PMA), but are involved in PMA-induced NETosis. [ABSTRACT FROM AUTHOR]

Members of the NOX/DUOX family of NADPH oxidases are responsible for regulated ROS production in diverse cells and tissues. Detection of NOX/DUOX proteins at the protein level remains an important challenge in the field. Here we report the development and characterization of a novel anti-NOX5 monoclonal antibody, which recognizes the human NOX5 protein in both Western blot, immunocytochemistry, and histochemistry applications. With the help of the antibody we could successfully detect both heterologously and endogenously expressed NOX5 in mammalian cells. Furthermore, we could also detect NOX5 protein in the human spleen, testis, and ovary. Immunohistochemical studies on human testis revealed that NOX5 localized to spermatogenic cells. This expression pattern was also supported by the result of in silico analysis of single-cell RNA sequencing data that indicated that NOX5 protein is present in developing spermatids and spermatocytes. Mature spermatozoa, however, did not contain detectable NOX5. In the human ovary, both immunostaining and single-cell RNA sequencing suggest that NOX5 is expressed in interstitial fibroblasts and theca cells. We also analyzed vascular cells for the presence of NOX5 and we found that NOX5 expression is a fairly specific feature of splenic endothelial cells. [ABSTRACT FROM AUTHOR]

We showed for the first time that polymorphisms rs2075938 and rs2075938 of the NCF4 gene are associated with the risk of chronic heart failure in patients with type 2 diabetes mellitus (n=1310). In particular, haplotypes ATGTCTAT (OR=1.74, 95%CI=1.23-2.47; p=0.0017) and ATATTCAC (OR=2.83, 95%CI=1.33-6.03; p=0.0072) of NCF4 increase the risk of chronic heart failure in type 2 diabetes mellitus patients. The results show that NADPH oxidase subunit NCF4 is involved in the molecular mechanisms of myocardial damage in type 2 diabetes mellitus. [ABSTRACT FROM AUTHOR]

The current work attempts to explore the influence of three extraction solvents on phytochemical composition, content of polyphenols, antioxidant potential, and antibacterial capacity of hydroethanolic, acetonic, and aqueous extracts from Moroccan Mentha longifolia leaves. To achieve this goal, the chemical composition was identified using an HPLC–DAD examination. The contents of polyphenols were assessed, while the total antioxidant capacity (TAC), the DPPH test, and the reducing power test (RP) were utilized to determine antioxidant capacity. To assess the antibacterial activity, the microdilution technique was carried out to calculate the minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) of extracts against four nosocomial bacteria (Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus). Additionally, the antibacterial and antioxidant activities of all tested extracts were examined in silico against the proteins NADPH oxidase and Bacillus cereus phospholipase C. Study reveals that M. longifolia extracts contain high phenolic and flavonoids. Additionally, the hydroethanolic extract contained the highest amounts of phenolic and flavonoid content, with values of 23.52 ± 0.14 mg Gallic acid equivalent/g dry weight and 17.62 ± 0.36 mg Quercetin Equivalent/g dry weight, respectively compared to the other two extracts. The same extract showed the best antioxidant capacity (IC50 = 39 µg/mL ± 0.00), and the higher RP (EC50 of 0.261 ± 0.00 mg/mL), compared to the acetonic and aqueous extract regarding these tests. Furthermore, the hydroethanolic and acetonic extracts expressed the highest TAC (74.40 ± 1.34, and 52.40 ± 0.20 mg EAA/g DW respectively), compared with the aqueous extract. Regarding antibacterial activity, the MIC value ranges between 1.17 and 12.50 mg/mL. The in-silico results showed that the antibacterial activity of all extracts is principally attributed to kaempferol and ferulic acid, while antioxidant capacity is attributed to ferulic acid. [ABSTRACT FROM AUTHOR]

Type 1 conventional dendritic cells (cDC1) are the most efficient cross-presenting cells that induce protective cytotoxic T cell response. However, the regulation of their homeostasis and function is incompletely understood. Here we observe a selective reduction of splenic cDC1 accompanied by excessive cell death in mice with Zeb1 deficiency in dendritic cells, rendering the mice more resistant to Listeria infection. Additionally, cDC1 from other sources of Zeb1-deficient mice display impaired cross-presentation of exogenous antigens, compromising antitumor CD8+ T cell responses. Mechanistically, Zeb1 represses the expression of microRNA-96/182 that target Cybb mRNA of NADPH oxidase Nox2, and consequently facilitates reactive-oxygen-species-dependent rupture of phagosomal membrane to allow antigen export to the cytosol. Cybb re-expression in Zeb1-deficient cDC1 fully restores the defective cross-presentation while microRNA-96/182 overexpression in Zeb1-sufficient cDC1 inhibits cross-presentation. Therefore, our results identify a Zeb1-microRNA-96/182-Cybb pathway that controls cross-presentation in cDC1 and uncover an essential role of Zeb1 in cDC1 homeostasis. Type 1 conventional dendritic cells (cDC1) play a pivotal role in the cross-presentation of antigens, enabling efficient CD8 + T cell response. Here authors show that the transcription factor Zeb1 essentially regulates this process via facilitating the reactive-oxygen-species-dependent rupture of phagosomal membrane to allow antigen export to the cytoplasm. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) can regulate the occurrence of autophagy, and effective control of the balance between ROS and autophagy may be an important strategy for Helicobacter pylori induced gastric-related diseases. In this study, infection with H. pylori led to a lower level of ILK phosphorylation and increased ROS generation. Knockdown of ILK enhanced total ROS generation, and upregulated NADPH oxidase (NOX) subunit p22-phox levels. Inhibition of NOXs affected total ROS generation. The inhibition of NOX and ROS generation reduced Nrf2 and HO-1 levels, and knockdown of ILK significantly enhanced Nrf2 levels in H. pylori-infected GES-1 cells. Activation of Nrf2 by DMF decreased ROS levels. Therefore, NOX-dependent ROS production regulated by ILK was essential for activation of Nrf2/HO-1 signaling pathways in H. pylori-infected GES-1 cells. Beclin1, ATG5 and LC3B-II levels were higher both in H. pylori-infected and ILK-knockdown GES-1 cells. In NAC-pretreated GES-1 cells infected with H. pylori, the LC3B-II level was decreased compared to that in cells after H. pylori infection alone. Stable low expression of ILK with further knockdown of Beclin1 or ATG5 significantly reduced LC3B-II levels in GES-1 cells, while with the addition of the autophagy inhibitor chloroquine (CQ), LC3B-II and p62 protein levels were both remarkably upregulated. H. pylori accelerated the accumulation of ROS and further led to the induction of ROS-mediated autophagy by inhibiting ILK levels. Together, these results indicate that H. pylori infection manipulates the NOX-ROS-Nrf2/HO-1-ROS loop to control intracellular oxygen stress and further induced ROS-mediated autophagy by inhibiting ILK levels. [ABSTRACT FROM AUTHOR]

Alcohol-mediated reactive oxygen species (ROS) play a vital role in intestinal barrier injury. However, the mechanism of ROS accumulation in enterocytes needs to be explored further. In our study, we found that chronic–binge ethanol-fed mice had increased levels of gut oxidative stress and high intestinal permeability. The transcription profiles of the colonic epithelial cells showed that the level of NADPH oxidase 1 (NOX1) was significantly elevated in alcohol-exposed mice compared with isocaloric-exposed mice. In vitro, NOX1 silencing alleviated ROS accumulation and the apoptosis of human colonic epithelial cells (NCM460), while NOX1 overexpression accelerated oxidative stress injury of NCM460 cells. Propionic acid was reduced in the gut of chronic–binge ethanol-fed mice, compared with isocaloric-fed mice, as observed through untargeted metabolomic analysis. Supplementation with propionate relieved ethanol-induced liver and intestinal barrier injuries and reduced the level of ROS accumulation and apoptosis of ethanol-induced colonic epithelial cells. Propionate alleviating NOX1 induced ROS injury of colonic epithelial cells, independent of G protein-coupled receptors. Propionate significantly inhibited histone deacetylase 2 (HDAC2) expressions both in ethanol-exposed colonic epithelial cells and TNF-α-treated NCM460. Chromatin immunoprecipitation (ChIP) assays showed that propionate suppressed the NOX1 expression by regulating histone acetylation in the gene promoter region. In conclusion, NOX1 induces oxidative stress injury of colonic epithelial cells in alcohol-related liver disease. Propionate, which can act as an endogenous HDAC2 inhibitor, can decrease levels of apoptosis of intestinal epithelial cells caused by oxidative stress. [ABSTRACT FROM AUTHOR]

The modulation of plant growth and development through reactive oxygen species (ROS) is a hallmark during the interactions with microorganisms, but how fungi and their molecules influence endogenous ROS production in the root remains unknown. In this report, we correlated the biostimulant effect of Trichoderma atroviride with Arabidopsis root development via ROS signaling. T. atroviride enhanced ROS accumulation in primary root tips, lateral root primordia, and emerged lateral roots as revealed by total ROS imaging through the fluorescent probe H2DCF-DA and NBT detection. Acidification of the substrate and emission of the volatile organic compound 6-pentyl-2H-pyran-2-one appear to be major factors by which the fungus triggers ROS accumulation. Besides, the disruption of plant NADPH oxidases, also known as respiratory burst oxidase homologs (RBOHs) including ROBHA, RBOHD, but mainly RBOHE, impaired root and shoot fresh weight and the root branching enhanced by the fungus in vitro. RbohE mutant plants displayed poor lateral root proliferation and lower superoxide levels than wild-type seedlings in both primary and lateral roots, indicating a role for this enzyme for T. atroviride–induced root branching. These data shed light on the roles of ROS as messengers for plant growth and root architectural changes during the plant-Trichoderma interaction. [ABSTRACT FROM AUTHOR]

The activation of receptor-interacting protein kinase 1 (RIPK1) by death-inducing signaling complex (DISC) formation is essential for triggering the necroptotic mode of cell death under apoptosis-deficient conditions. Thus, targeting the induction of necroptosis by modulating RIPK1 activity could be an effective strategy to bypass apoptosis resistance in certain types of cancer. In this study, we screened a series of arborinane triterpenoids purified from Rubia philippinesis and identified rubiarbonol B (Ru–B) as a potent caspase-8 activator that induces DISC-mediated apoptosis in multiple types of cancer cells. However, in RIPK3-expressing human colorectal cancer (CRC) cells, the pharmacological or genetic inhibition of caspase-8 shifted the mode of cell death by Ru–B from apoptosis to necroptosis though upregulation of RIPK1 phosphorylation. Conversely, Ru–B-induced cell death was almost completely abrogated by RIPK1 deficiency. The enhanced RIPK1 phosphorylation and necroptosis triggered by Ru–B treatment occurred independently of tumor necrosis factor receptor signaling and was mediated by the production of reactive oxygen species via NADPH oxidase 1 in CRC cells. Thus, we propose Ru–B as a novel anticancer agent that activates RIPK1-dependent cell death via ROS production, and suggest its potential as a novel necroptosis-targeting compound in apoptosis-resistant CRC. [ABSTRACT FROM AUTHOR]

Plasma membrane located NADPH oxidase (NOX) and H+-ATPase function cooperatively during early root growth to maintain the membrane electrical balance while mediating cell growth through wall relaxation. A potent transcriptional co-regulation of the two enzymes has also been identified which further highlights the essentiality of NOX-PM H+-ATPase feed-forward loop, mediated by H2O2 and Ca+ 2, during root growth. The pathway from superoxide (O2˙ˉ) generation to cell elongation involves intermediary conversion of O2˙ˉ to H2O2 by superoxide dismutase (SOD) and subsequently by class III peroxidase (Prx) to produce ˙OH radical, necessary for wall polysaccharide cleavage. Present work demonstrates further the involvement of polyamine metabolism in the ROS-mediated process of root growth regulation. Thus, in addition to retardation of root growth, inhibition of PAO (polyamine oxidase) results in significant diminution of NOX and PM H+-ATPase activities. On the other hand, exogenous application of PAs (viz. putrescine, spermidine and spermine) stimulates the NOX-PM H+-ATPase cascade resulting in augmented production of O2˙ˉ and H2O2. Interestingly, blocking of NOX and PM H+-ATPase activities (through specific inhibitors) as well as quenching of their products (through dedicated antagonistic agents) drastically reduced PAO activity as observed in both spectrophotometric and native PAGE assays. Inhibition of PAO has also been recorded when treated with Ca+ 2-chelator and Ca+ 2-channel blocker. Correlating the present observations with earlier findings it has been hypothesized that H2O2 and Ca+ 2 are serving as mediators of interplay between NOX-PM H+-ATPase cascade and PA metabolism during early root growth in Vigna radiata (L.) Wilczek seedlings. [ABSTRACT FROM AUTHOR]

Blood phagocytes, such as neutrophils and monocytes, generate reactive oxygen species (ROS) as a part of host defense response against infections. We investigated the mechanism of Fcγ-Receptor (FcγR) mediated ROS production in these cells to understand how they contribute to anti-malarial immunity. Plasmodium falciparum merozoites opsonized with naturally occurring IgG triggered both intracellular and extracellular ROS generation in blood phagocytes, with neutrophils being the main contributors. Using specific inhibitors, we show that both FcγRIIIB and FcγRIIA acted synergistically to induce ROS production in neutrophils, and that NADPH oxidase 2 and the PI3K intracellular signal transduction pathway were involved in this process. High levels of neutrophil ROS were also associated with protection against febrile malaria in two geographically diverse malaria endemic regions from Ghana and India, stressing the importance of the cooperation between anti-malarial IgG and neutrophils in triggering ROS-mediated parasite killing as a mechanism for naturally acquired immunity against malaria. FcγR-mediated signaling by cytophilic IgG against Plasmodium falciparum merozoites triggers ROS generation predominantly in neutrophils as a mechanism contributing to naturally acquired immunity against malaria in endemic regions in Ghana and India. [ABSTRACT FROM AUTHOR]

An investigation was carried out to evaluate the effect of graphene quantum dots (GQD) and its nanocomposites on germination, growth, biochemical, histological, and major ROS detoxifying antioxidant enzyme activities involved in salinity stress tolerance of wheat. Seedlings were grown on nutrient-free sand and treatment solutions were applied through solid matrix priming and by foliar spray. Control seedlings under salinity stress exhibited a reduction in photosynthetic pigment, sugar content, growth, increased electrolyte leakage, and lipid peroxidation, whereas iron-manganese nanocomposites doped GQD (FM_GQD) treated seedlings were well adapted and performed better compared to control. Enzymatic antioxidants like catalase, peroxidase, glutathione reductase and NADPH oxidase were noted to increase by 40.5, 103.2, 130.19, and 141.23% respectively by application of FM_GQD. Histological evidence confirmed a lower extent of lipid peroxidation and safeguarding the plasma membrane integrity through osmolyte accumulation and redox homeostasis. All of these interactive phenomena lead to an increment in wheat seedling growth by 28.06% through FM_GQD application. These findings highlight that micronutrient like iron, manganese doped GQD can be a promising nano-fertilizer for plant growth and this article will serve as a reference as it is the very first report regarding the ameliorative role of GQD in salt stress mitigation. [ABSTRACT FROM AUTHOR]

In tauopathies, abnormal deposition of intracellular tau protein followed by gradual elevation of tau in cerebrospinal fluids and neuronal loss has been documented, however, the mechanism how actually neurons die under tau pathology is largely unknown. We have previously shown that extracellular tau protein (2N4R isoform) can stimulate microglia to phagocytose live neurons, i.e. cause neuronal death by primary phagocytosis, also known as phagoptosis. Here we show that tau protein induced caspase-1 activation in microglial cells via 'Toll-like' 4 (TLR4) receptors and neutral sphingomyelinase. Tau-induced neuronal loss was blocked by caspase-1 inhibitors (Ac-YVAD-CHO and VX-765) as well as by TLR4 antibodies. Inhibition of caspase-1 by Ac-YVAD-CHO prevented tau-induced exposure of phosphatidylserine on the outer leaflet of neuronal membranes and reduced microglial phagocytic activity. We also show that suppression of NLRP3 inflammasome, which is down-stream of TLR4 receptors and mediates caspase-1 activation, by a specific inhibitor (MCC550) also prevented tau-induced neuronal loss. Moreover, NADPH oxidase is also involved in tau-induced neurotoxicity since neuronal loss was abolished by its pharmacological inhibitor. Overall, our data indicate that extracellular tau protein stimulates microglia to phagocytose live neurons via Toll-like 4 receptor–NLRP3 inflammasome–caspase-1 axis and NADPH oxidase, each of which may serve as a potential molecular target for pharmacological treatment of tauopathies. [ABSTRACT FROM AUTHOR]

People with sedentary lifestyles engage in minimal or no physical activity. A sedentary lifestyle promotes dysregulation of cellular redox balance, diminishes mitochondrial function, and increases NADPH oxidase activity. These changes collectively increase cellular oxidative stress, which alters endothelial function by oxidizing LDL-C, reducing NO production, and causing eNOS uncoupling. Reduced levels of nitric oxide (NO) leads to vasoconstriction, vascular remodeling, and vascular inflammation. Exercise modulates reactive oxygen species (ROS) to modify NRF2-KEAP signaling, leading to the activation of NRF2 to alleviate oxidative stress. While regular moderate exercise activates NRF2 through ROS production, high-intensity intermittent exercise stimulates NRF2 activation to a greater degree by reducing KEAP levels, which can be more beneficial for sedentary individuals. We review the damaging effects of a sedentary lifestyle on the vascular system and the health benefits of regular and intermittent exercise. [ABSTRACT FROM AUTHOR]

Electronic cigarettes (E-cigarettes) have recently become a popular alternative to traditional tobacco cigarettes. Despite being marketed as a healthier alternative, increasing evidence shows that E-cigarette vapour could cause adverse health effects. It has been postulated that degradation products of E-cigarette liquid, mainly reactive aldehydes, are responsible for those effects. Previously, we have demonstrated that E-cigarette vapour exposure causes oxidative stress, inflammation, apoptosis, endothelial dysfunction and hypertension by activating NADPH oxidase in a mouse model. To better understand oxidative stress mechanisms, we have exposed cultured endothelial cells and macrophages to condensed E-cigarette vapour (E-cigarette condensate) and acrolein. In both endothelial cells (EA.hy 926) and macrophages (RAW 264.7), we have observed that E-cigarette condensate incubation causes cell death. Since recent studies have shown that among toxic aldehydes found in E-cigarette vapour, acrolein plays a prominent role, we have incubated the same cell lines with increasing concentrations of acrolein. Upon incubation with acrolein, a translocation of Rac1 to the plasma membrane has been observed, accompanied by an increase in oxidative stress. Whereas reactive oxygen species (ROS) formation by acrolein in cultured endothelial cells was mainly intracellular, the release of ROS in cultured macrophages was both intra- and extracellular. Our data also demonstrate that acrolein activates the nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant pathway and, in general, could mediate E-cigarette vapour-induced oxidative stress and cell death. More mechanistic insight is needed to clarify the toxicity associated with E-cigarette consumption and the possible adverse effects on human health. [ABSTRACT FROM AUTHOR]

Esophageal adenocarcinoma carries a poor prognosis associated with a 5-year survival rate of 12.5–20%. Therefore, a new therapeutic modality is needed for this lethal tumor. Carnosol is a phenolic diterpene purified from the herbs such as rosemary and Mountain desert sage and has been shown to have anticancer activities in multiple cancers. In this study we examined the effect of carnosol on cell proliferation in esophageal adenocarcinoma cells. We found that carnosol dose-dependently decreased cell proliferation in FLO-1 esophageal adenocarcinoma cells and significantly increased caspase-3 protein, indicating that carnosol decreases cell proliferation and increases cell apoptosis in FLO-1 cells. Carnosol significantly increased H2O2 production and N-acetyl cysteine, a reactive oxygen species (ROS) scavenger, significantly inhibited carnosol-induced decrease in cell proliferation, indicating that ROS may mediate carnosol-induced decrease in cell proliferation. Carnosol-induced decrease in cell proliferation was partially reversed by NADPH oxidase inhibitor apocynin, suggesting that NADPH oxidases may be partially involved in carnosol's effect. In addition, carnosol significantly downregulated SODD protein and mRNA expression and knockdown of SODD significantly inhibited the carnosol-induced reduction in cell proliferation, suggesting that downregulation of SODD may contribute to carnosol-induced reduction in cell proliferation. We conclude that carnosol dose-dependently decreased cell proliferation and significantly increased caspase-3 protein. Carnosol's effect may be through the overproduction of ROS and the downregulation of SODD. Carnosol might be useful for the treatment of esophageal adenocarcinoma. [ABSTRACT FROM AUTHOR]

Cold stress is an adverse environmental condition that limits the growth and yield of grapes. Brassinosteroids (BRs) are a class of polyhydroxylated steroidal phytohormones that induce plant resistance to biotic and abiotic stresses. Hydrogen peroxide (H2O2) is a crucial signaling molecule that participates in various physiological processes and abiotic stresses. However, the role of endogenous H2O2 in BR-induced cold stress tolerance of grape seedlings was unclear. Here, we showed that BR application significantly induced cold tolerance of grape seedlings via maintaining higher antioxidases activities, osmoprotectant levels, maximum photosystem II quantum yield, chlorophyll content, and less cell membrane damage, and regulating phytohormone levels. Even more importantly, exogenous BR treatment triggered the upregulation of VvRBOHa, VvRBOHb and VvRBOHe genes expression, the activity of NADPH oxidase, as well as the levels of endogenous H2O2 in the seedlings exposed to cold stress. Pretreatment with dimethylthiourea (DMTU, an H2O2 scavenger) significantly blocked BR-induced H2O2 production under cold stress by reducing NADPH oxidase encoding genes expression and NADPH oxidase activity. Moreover, inhibiting endogenous H2O2 eliminated BR-induced increase in Fv/Fm value and superoxide dismutase, catalase, ascorbate peroxidase, peroxidase activities, and the changes of phytohormone levels. Taken together, we provide evidence supporting the essential roles of RBOH-dependent H2O2 in BR-induced cold tolerance in grape seedlings. [ABSTRACT FROM AUTHOR]

NOX5 is the last member of the NADPH oxidase (NOXs) family to be identified and presents some specific characteristics differing from the rest of the NOXs. It contains four Ca2+ binding domains at the N-terminus and its activity is regulated by the intracellular concentration of Ca2+. NOX5 generates superoxide (O2•−) using NADPH as a substrate, and it modulates functions related to processes in which reactive oxygen species (ROS) are involved. Those functions appear to be detrimental or beneficial depending on the level of ROS produced. For example, the increase in NOX5 activity is related to the development of various oxidative stress-related pathologies such as cancer, cardiovascular, and renal diseases. In this context, pancreatic expression of NOX5 can negatively alter insulin action in high-fat diet-fed transgenic mice. This is consistent with the idea that the expression of NOX5 tends to increase in response to a stimulus or a stressful situation, generally causing a worsening of the pathology. On the other hand, it has also been suggested that it might have a positive role in preparing the body for metabolic stress, for example, by inducing a protective adipose tissue adaptation to the excess of nutrients supplied by a high-fat diet. In this line, its endothelial overexpression can delay lipid accumulation and insulin resistance development in obese transgenic mice by inducing the secretion of IL-6 followed by the expression of thermogenic and lipolytic genes. However, as NOX5 gene is not present in rodents and human NOX5 protein has not been crystallized, its function is still poorly characterized and further extensive research is required. [ABSTRACT FROM AUTHOR]

Background: Chronic granulomatous disease (CGD) is a primary immunodeficiency with increased susceptibility to several bacteria, fungi, and mycobacteria, caused by defective or null superoxide production by the NADPH oxidase enzymatic complex. Accepted treatment consists mainly of antimicrobial prophylaxis. The role of human recombinant subcutaneous interferon-gamma (IFNγ) is less clear since the available evidence on its efficacy derives mainly from a single clinical trial that has been challenged. Objective: We aimed to assess the efficacy and safety of IFNγ as an added treatment for CGD when compared to antimicrobial prophylaxis alone. Methods: A literature search was conducted using MeSH terms "Chronic granulomatous disease" AND ("interferon gamma" OR "interferon-gamma"), as well as antibiotics, placebo, no therapy, clinical trial, and trial, on MEDLINE, EMBASE, LILACS, WHOs, CENTRAL, KOREAMED, The Cochrane Library, clinicaltrials.gov, and abstracts from meetings, from 1976 to July 2022. We included clinical trials (CT) and prospective follow-up studies and registered the number of serious infections (requiring hospitalization and IV antibiotics) and deaths, adverse events, and autoimmune complications, in patients treated for CGD with antimicrobial prophylaxis plus IFN-γ, versus antimicrobial prophylaxis alone. We assessed the quality of the studies using risk of bias and STROBE. We performed a meta-analysis by calculating both Peto's odds ratio (OR) and risk reduction (RR) through the Mantel–Haenszel method with a fixed-effect model, using Review Manager 5.4, and we reported the number needed to treat (NNT). Results: We identified 54 matches from databases and 4 from other sources. We excluded 12 duplicates, 7 titles, and 9 abstracts for relevance, after which we had 30 eligible studies. Twenty-four were then excluded after reading the full text. Six papers were included: one randomized CT and 5 follow-up studies. In total, 324 patients with Chronic granulomatous disease were followed for 319 months under treatment with antibiotic prophylaxis plus interferon-gamma or placebo (or antibiotic prophylaxis alone), reported between the years 1991 and 2016. Three of the studies included a control group, allowing for the aggregate analysis of efficacy (prevention of serious infections). The aggregate OR was 0.49, with a 95% confidence interval of 0.19 to 1.23. The risk ratio for serious infection was 0.56 (95%CI 0.35–0.90) under IFN-γ. The meta-analysis thus favors interferon-gamma for a risk reduction of serious infection. Discussion: The results from this meta-analysis support the use of IFN-γ in the treatment of patients with CGD. However, we found insufficient clinical evidence and believe more clinical trials are needed to better assess the efficacy and long-term safety of IFN-γ. [ABSTRACT FROM AUTHOR]

New N-substituted oxime derivatives (5b, 5d-g, 5i-k, and 5m) and known compounds (5a, 5c, 5h, 5g, 5l, and 5n-q) were obtained by reacting phenyl and butyl oxime chloride analogs with aniline, piperazine derivatives, piperidine, and diethylamine. Structures of all new compounds were determined by 1H NMR, 13C NMR, HRMS, and FTIR methods. All compounds were evaluated in vitro for their antiradical activity and hydrogen peroxide scavenging activity. Compounds 5g, 5h, 5i, 5j, 5k, 5l, 5m, and 5p have shown good antiradical activities with EC50 values < 1 (conc. antiradical (µM)/conc. DPPH (µM)). Similar results were obtained in the peroxide scavenging activity tests. These results have shown that piperidine and butyl substitution greatly increases the antiradical activity of the oximes. Compounds 5l and 5m were found to be the best radical scavengers. In addition, molecular docking studies were performed for compounds (5a-q) against CP450 (CYP1A2), NADPH oxidase, and Xanthine oxidase to predict their antioxidant capabilities through ROS-producing enzyme inhibitions. [ABSTRACT FROM AUTHOR]

Fibroblast growth factor-18 (FGF18) has diverse organ development and damage repair roles. However, its role in cardiac homeostasis following hypertrophic stimulation remains unknown. Here we investigate the regulation and function of the FGF18 in pressure overload (PO)-induced pathological cardiac hypertrophy. FGF18 heterozygous (Fgf18+/−) and inducible cardiomyocyte-specific FGF18 knockout (Fgf18-CKO) male mice exposed to transverse aortic constriction (TAC) demonstrate exacerbated pathological cardiac hypertrophy with increased oxidative stress, cardiomyocyte death, fibrosis, and dysfunction. In contrast, cardiac-specific overexpression of FGF18 alleviates hypertrophy, decreased oxidative stress, attenuates cardiomyocyte apoptosis, and ameliorates fibrosis and cardiac function. Tyrosine-protein kinase FYN (FYN), the downstream factor of FGF18, was identified by bioinformatics analysis, LC-MS/MS and experiment validation. Mechanistic studies indicate that FGF18/FGFR3 promote FYN activity and expression and negatively regulate NADPH oxidase 4 (NOX4), thereby inhibiting reactive oxygen species (ROS) generation and alleviating pathological cardiac hypertrophy. This study uncovered the previously unknown cardioprotective effect of FGF18 mediated by the maintenance of redox homeostasis through the FYN/NOX4 signaling axis in male mice, suggesting a promising therapeutic target for the treatment of cardiac hypertrophy. Although the role of FGFs in cardiovascular disease has attracted extensive attention, the potential role of FGF18 in pathological cardiac hypertrophy remains unknown. Here, the authors show the cardioprotective effect of FGF18 is mediated by maintaining redox homeostasis through FYN/Nox4 signaling. [ABSTRACT FROM AUTHOR]

Oxidative stress, caused by the over production of oxidants or inactivity of antioxidants, can modulate the redox state of several target proteins such as tyrosine kinases, mitogen-activated protein kinases and tyrosine phosphatases. c-Src is one such non-receptor tyrosine kinase which activates NADPH oxidases (Noxs) in response to various growth factors and shear stress. Interaction between c-Src and Noxs is influenced by cell type and primary messengers such as angiotensin II, which binds to G-protein coupled receptor and activates the intracellular signaling cascade. c-Src stimulated activation of Noxs results in elevated release of intracellular and extracellular reactive oxygen species (ROS). These ROS species disturb vascular homeostasis and cause cardiac hypertrophy, coronary artery disease, atherosclerosis and hypertension. Interaction between c-Src and ROS in the pathobiology of cardiac fibrosis is hypothesized to be influenced by cell type and stimuli. c-Src and ROS have a bidirectional relationship, thus increased ROS levels due to c-Src mediated activation of Noxs can further activate c-Src by promoting the oxidation and sulfenylation of critical cysteine residues. This review highlights the role of c-Src and ROS in mediating downstream signaling pathways underlying cardiovascular diseases. Furthermore, due to the central role of c-Src in activation of various signaling proteins involved in differentiation, migration, proliferation, and cytoskeletal reorganization of vascular cells, it is presented as therapeutic target for treating cardiovascular diseases except cardiac fibrosis. [ABSTRACT FROM AUTHOR]

Background: Exposure to ionizing is known to cause persistent cellular oxidative stress and NADPH oxidase (Nox) is a major source of cellular oxidant production. Chronic oxidative stress is associated with a myriad of human diseases including gastrointestinal cancer. However, the roles of NADPH oxidase in relation of long-term oxidative stress in colonic epithelial cells after radiation exposure are yet to be clearly established. Methods and results: Mice were exposed either to sham or to 0.5 Gy γ radiation, and NADPH oxidase, oxidative stress, and related signaling pathways were assessed in colon samples 60 days after exposure. Radiation exposure led to increased expression of colon-specific NADPH oxidase isoform, Nox1, as well as upregulation of its modifiers such as Noxa1 and Noxo1 at the mRNA and protein level. Co-immunoprecipitation experiments showed enhanced binding of Rac1, an activator of NADPH oxidase, to Nox1. Increased 4-hydroxynonenal, 8-oxo-dG, and γH2AX along with higher protein carbonylation levels suggest increased oxidative stress after radiation exposure. Immunoblot analysis demonstrates upregulation of Ras/p38 pathway, and Gata6 and Hif1α after irradiation. Increased staining of β-catenin, cyclinD1, and Ki67 after radiation was also observed. Conclusions: In summary, data show that exposure to a low dose of radiation was associated with upregulation of NADPH oxidase and its modifiers along with increased Ras/p38/Gata6 signaling in colon. When considered along with oxidative damage and proliferative markers, our observations suggest that the NADPH oxidase pathway could be playing a critical role in propagating long-term oxidative stress after radiation with implications for colon carcinogenesis. [ABSTRACT FROM AUTHOR]

Reactive Oxygen Species (ROS) play an important role in oxidative stress and are related to the lipid accumulation in microalgae. Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase can oxidize O2 to O2− ultimately. However, the function of NADPH oxidase and its contribution to the production of the intracellular total ROS are still unclear. In this study, the function of NADPH oxidase in Chlorella pyrenoidosa (C. pyrenoidosa) was investigated by adding activators Ca2+ and NADPH and inhibitors EGTA, LaCl3, DPI and BAPTA of NADPH oxidase. The results show that the addition of activators of Ca2+ or NADPH significantly increased the intracellular concentrations of ROS molecules (H2O2, O2−, and OH·) in C. pyrenoidosa. Moreover, the intracellular ROS level was higher under the nitrogen-deficient and phosphorus-deficient conditions than in control condition, but the addition of the inhibitors (EGTA, LaCl3, DPI, and BAPTA) of NADPH oxidase significantly reduced the intracellular concentrations of H2O2, O2−, and OH·. The study shows that NADPH oxidase actively participated in the production of intracellular ROS in C. pyrenoidosa, demonstrating that NADPH oxidase was another important element in the production of intracellular ROS in addition to mitochondria, chloroplasts and lysozymes in microalgae. [ABSTRACT FROM AUTHOR]

Salinity stress is the major abiotic stress that affects crop production and productivity as it has a multifarious negative effect on the growth and development of the plant. Salinity stress stimulates the accumulation of reactive oxygen species (ROS) which is toxic to cells at higher concentrations. At lower concentrations, these molecules help in the mitigation of salinity stress through a series of signal transduction mechanisms. The respiratory burst by NADPH oxidase leads to an increase in ROS generation. It is a key signalling node in the plant gene network and helps to integrate the signal transduction with ROS signalling. Reactive nitrogen species (RNS) are free radical and non-radical reactive molecules that are also produced under salinity stress and lead to nitrosative stress by regulating SOS, MAPK dependent, Ca2+ dependent and G-protein dependent pathways. The reactive sulphur species (RSS) is a strong oxidizing agent that preferably attacks the thiol functional group. Activation of the different signalling components like ROS, RNS, RSS, SOS, Calcium, MAPK signalling and cross-talk between different signalling pathways and phytohormones have been considered as the main mechanism for ion homeostasis and Na+ exclusion at the cellular level. These reactive species and their interaction upregulate the gene expression and phosphorylation level of different membrane transporters viz., PM H+-ATPase and Na+/ H+ antiporter which might endure salinity tolerance in plants. This review aims to describe the interplay/crosstalk amongst reactive species and phytohormones under salinity stress. Moreover, mechanistic insight of reactive species-mediated stress regulation and the response has also been discussed which will be helpful for the development of stress-tolerant cultivars. [ABSTRACT FROM AUTHOR]