NADPH Oxidase Inhibitor Research Articles

Inhibition of oxidative stress delays senescence and augments functional capacity of endothelial progenitor cells

Ageing is characterised by a progressive loss of vascular endothelial function and integrity. Endothelial progenitor cells (EPCs) play an integral role in endothelial regeneration but are prone to age-dependent changes which may accelerate their senescence and diminish their availability and functionality. Considering these, we firstly investigated the quantity of circulating EPCs in older (73.3 ± 7.2 years) and younger (40.2 ± 14.3 years) healthy volunteers and showed sharp declines in the number of EPCs expressing stemness markers (CD34 + and/or CD133 + ) in older people. These coincided with the decreases in total anti-oxidant capacity (TAC) and concomitant increases in plasma levels of pro-inflammatory cytokine, TNF-α and anti-angiogenic factor, endostatin and thrombospondin-1. The subsequent experimental studies to scrutinise the effect of ageing on molecular and functional properties of outgrowth endothelial cells (OECs), the functional subtype of EPCs, showed that chronological ageing, mimicked by replicative senescence, profoundly impaired proliferation, migration, tubulogenesis, and blood–brain barrier (BBB)-forming capacity of these cells. Similar to those seen in the clinical observational studies, senescent OECs also manifested decreased TAC and increased pro-oxidant NADPH oxidase activity and endostatin level. Suppressing oxidative stress level using structurally and functionally distinct anti-oxidants, namely vitamin C or VAS2870, an NADPH oxidase inhibitor, delayed OEC senescence and restored their tubulogenic and BBB-forming capacities. In conclusion, the enhanced oxidative stress level that develops during physiological ageing may promote EPC senescence and evoke endothelial dysfunction. Effective control of oxidative stress using either compound somewhat delays both phenomena and augments EPC functionality.

Disruption of mitochondrial redox homeostasis as a mechanism of antimony-induced reactive oxygen species and cytotoxicity

Occupational and environmental Sb exposure has been associated with increased risk of respiratory diseases and lung cancer, but the toxicities and molecular mechanisms of Sb have been less investigated. In the present study, we first analyzed the Sb toxicity profile of lung adenocarcinoma A549 cells, and found that Sb dose-dependently decreased the cell viability and arrested cell cycle at G2/M but did not induce apoptosis. We next investigated the role of reactive oxygen species (ROS) involved in Sb-induced cytotoxicity. The results showed that Sb did not significantly induce cytosolic ROS production by NADPH oxidase (NOX) and the NOX inhibitors did not ameliorate the Sb-induced cell viability loss in A549 cells. However, the level of mitochondrial ROS (mtROS) was significantly increased in Sb-exposed cells and the mitochondria-targeted antioxidant significantly improved cell viability. These results suggested that mitochondria but not NOX is the major source of ROS production and mtROS plays a critical role in Sb-induced cytotoxicity. Furthermore, we found that Sb induced mitochondria dysfunction including the significant decrease of ATP level and mitochondrial membrane potential. Finally, Sb exposure decreased the activity of complex I and complex III, the level of -SH and GSH in mitochondria, and the activity of mitochondrial GR, GPx and TrxR, but increased the mitochondrial SOD activity, suggesting the disruption of mitochondrial redox homeostasis. Taken together, these findings suggested that Sb impaired mitochondrial redox homeostasis, resulting in formation of mtROS, thereby inhibited mitochondrial function and led to cytotoxicity.

HO-1 Upregulation by Kaempferol via ROS-Dependent Nrf2-ARE Cascade Attenuates Lipopolysaccharide-Mediated Intercellular Cell Adhesion Molecule-1 Expression in Human Pulmonary Alveolar Epithelial Cells.

Lung inflammation is a pivotal event in the pathogenesis of acute lung injury. Heme oxygenase-1 (HO-1) is a key antioxidant enzyme that could be induced by kaempferol (KPR) and exerts anti-inflammatory effects. However, the molecular mechanisms of KPR-mediated HO-1 expression and its effects on inflammatory responses remain unknown in human pulmonary alveolar epithelial cells (HPAEpiCs). This study aimed to verify the relationship between HO-1 expression and KPR treatment in both in vitro and in vivo models. HO-1 expression was determined by real time-PCR, Western blotting, and promoter reporter analyses. The signaling components were investigated by using pharmacological inhibitors or specific siRNAs. Chromatin immunoprecipitation (ChIP) assay was performed to investigate the interaction between nuclear factor erythroid-2-related factor (Nrf2) and antioxidant response elements (ARE) binding site of HO-1 promoter. The effect of KPR on monocytes (THP-1) binding to HPAEpiCs challenged with lipopolysaccharides (LPS) was determined by adhesion assay. We found that KPR-induced HO-1 level attenuated the LPS-induced intercellular cell adhesion protein 1 (ICAM-1) expression in HPAEpiCs. KPR-induced HO-1 mRNA and protein expression also attenuated ICAM-1 expression in mice. Tin protoporphyrin (SnPP)IX reversed the inhibitory effects of KPR in HPAEpiCs. In addition, in HPAEpiCs, KPR-induced HO-1 expression was abolished by both pretreating with the inhibitor of NADPH oxidase (NOX, apocynin (APO)), reactive oxygen species (ROS) (N-acetyl-L-cysteine (NAC)), Src (Src kinase inhibitor II (Srci II)), Pyk2 (PF431396), protein kinase C (PKC)α (Gö6976), p38 mitogen-activated protein kinase (MAPK) inhibitor (p38i) VIII, or c-Jun N-terminal kinases (JNK)1/2 (SP600125) and transfection with their respective siRNAs. The transcription of the homx1 gene was enhanced by Nrf2 activated by JNK1/2 and p38α MAPK. The binding activity between Nrf2 and HO-1 promoter was attenuated by APO, NAC, Srci II, PF431396, or Gö6983. KPR-mediated NOX/ROS/c-Src/Pyk2/PKCα/p38α MAPK and JNK1/2 activate Nrf2 to bind with ARE on the HO-1 promoter and induce HO-1 expression, which further suppresses the LPS-mediated inflammation in HPAEpiCs. Thus, KPR exerts a potential strategy to protect against pulmonary inflammation via upregulation of the HO-1.

2,3,5,4'-Tetrahydroxystilbene-2-O-β-glucoside Attenuates Reactive Oxygen Species-Dependent Inflammation and Apoptosis in Porphyromonas gingivalis-Infected Brain Endothelial Cells.

We recently reported that the periodontopathic bacteria Porphyromonas gingivalis (P. gingivalis) initiates an inflammatory cascade that disrupts the balance of reactive oxygen species (ROS), resulting in apoptotic cell death in brain endothelial cells. An extract from Polygonum multiflorum Thunb., 2,3,5,4′-Tetrahydroxystilbene-2-O-β-glucoside (THSG) has been well-reported to diminish the inflammation in many disease models. However, the effects of THSG in the area of the brain–oral axis is unknown. In this study, we examined the effects of THSG in P. gingivalis-stimulated inflammatory response and apoptotic cell death in brain endothelial cells. THSG treatment remarkably lessened the upregulation of IL-1β and TNF-α proteins in bEnd.3 cells infected with P. gingivalis. Treatment of THSG further ameliorated brain endothelial cell death, including apoptosis caused by P. gingivalis. Moreover, the present study showed that the inhibitory effects on NF-κB p65 and antiapoptotic properties of THSG is through inhibiting the ROS pathway. Importantly, the ROS inhibitory potency of THSG is similar to a ROS scavenger N-Acetyl-L-Cysteine (NAC) and NADPH oxidase inhibitor apocynin. Furthermore, the protective effect of THSG from P. gingivalis infection was further confirmed in primary mouse brain endothelial cells. Taken together, this study indicates that THSG attenuates an ROS-dependent inflammatory response and cell apoptosis in P. gingivalis-infected brain endothelial cells. Our results also suggest that THSG could be a potential herbal medicine to prevent the risk of developing cerebrovascular diseases from infection of periodontal bacteria.

Reactive Oxygen Species Partly Mediate DNA Methylation in Responses to Different Heavy Metals in Pokeweed.

DNA methylation is a rapid response strategy promoting plant survival under heavy metal (HM) stress. However, the roles of DNA methylation underlying plant adaptation to HM stress remain largely unknown. Here, we used pokeweed, a hyperaccumulator of manganese (Mn) and cadmium (Cd), to explore responses of plant to HM stress at phenotypic, transcriptional and DNA methylation levels. Mn- and Cd-specific response patterns were detected in pokeweed. The growth of pokeweed was both inhibited with exposure to excess Mn/Cd, but pokeweed distinguished Mn and Cd with different subcellular distributions, ROS scavenging systems, transcriptional patterns including genes involved in DNA methylation, and differentially methylated loci (DML). The number of DML between Mn/Cd treated and untreated samples increased with increased Mn/Cd concentrations. Meanwhile, pretreatment with NADPH oxidase inhibitors prior to HM exposure markedly reduced HM-induced reactive oxygen species (ROS), which caused reductions in expressions of DNA methylase and demethylase in pretreated samples. The increased levels of HM-induced demethylation were suppressed with alleviated ROS stress, and a series of HM-related methylated loci were also ROS-related. Taken together, our study demonstrates that different HMs affect different DNA methylation sites in a dose-dependent manner and changes in DNA methylation under Mn/Cd stress are partly mediated by HM-induced ROS.

The Balance between Different ROS on Tobacco Stigma during Flowering and Its Role in Pollen Germination.

The concept of ROS as an important factor controlling pollen germination and tube growth has become generally accepted in the last decade. However, the relationship between various ROS and their significance for the success of in vivo germination and fertilization remained unexplored. For the present study, we collected Nicotiana tabacum stigma exudate on different stages of stigma maturity before and after pollination. Electron paramagnetic resonance (EPR) and colorimetric analysis were used to assess levels of O•2− and H2O2 on stigma. Superoxide dismutase activity in the stigma tissues at each stage was evaluated zymographically. As the pistil matured, the level of both ROS decreased markedly, while the activity of SOD increased, and, starting from the second stage, the enzyme was represented by two isozymes: Fe SOD and Cu/Zn SOD, which was demonstrated by the in-gel inhibitory analysis. Selective suppression of Cu/Zn SOD activity shifted the ROS balance, which was confirmed by EPR. This shift markedly reduced the rate of pollen germination in vivo and the fertilization efficiency, which was estimated by the seed set. This result showed that hydrogen peroxide is a necessary component of stigma exudate, accelerates germination and ensures successful reproduction. A decrease in O•2− production due to NADPH oxidase inhibition, although it slowed down germination, did not lead to a noticeable decrease in the seed set. Thus, the role of the superoxide radical can be characterized as less important.

NOX2-derived hydrogen peroxide impedes the AMPK/Akt-mTOR signaling pathway contributing to cell death in neuronal cells

Oxidative stress is closely related to the pathogenesis of Parkinson's disease (PD), a typical neurodegenerative disease. NADPH oxidase 2 (NOX2) is involved in hydrogen peroxide (H2O2) generation. Recently, we have reported that treatment with H2O2 and PD toxins, including 6-hydroxydopamine (6-OHDA), 1-Methyl-4-phenylpyridin-1-ium (MPP+) and rotenone, induces neuronal apoptosis by inhibiting the mTOR pathway. Here, we show that treatment with 6-OHDA, MPP+ or rotenone induced H2O2 generation by upregulating the levels of NOX2 and its regulatory proteins (p22phox, p40phox, p47phox, p67phox, and Rac1), leading to apoptotic cell death in PC12 cells and primary neurons. Inhibition of NOX2 with apocynin or diphenyleneiodonium, or knockdown of NOX2 powerfully attenuated PD toxins-evoked NOX2 and H2O2, thereby hindering activation of AMPK, inhibition of Akt/mTOR, and induction of apoptosis in neuronal cells. Pretreatment with catalase, a H2O2-scavenging enzyme, blocked the effects of PD toxins on NOX2-dependent H2O2 production, AMPK/Akt/mTOR signaling and apoptosis in the cells. Similar effects were also seen in the cells pretreated with Mito-TEMPO, a mitochondria-selective superoxide scavenger, implying a mitochondrial H2O2-dependent mechanism involved. Further research revealed that ectopic expression of constitutively active Akt or dominant negative AMPKα, or inhibition of AMPK with compound C suppressed PD toxins-induced expression of NOX2 and its regulatory proteins, as well as consequential H2O2 production and apoptosis in the cells. Taken together, these results indicate that certain PD toxins can impede the AMPK/Akt-mTOR signaling pathway leading to neuronal apoptosis by eliciting NOX2-derived H2O2 production. Our findings suggest that neuronal loss in PD may be prevented by regulating the NOX2, AMPK/Akt-mTOR signaling and/or applying antioxidants to ameliorate oxidative stress.

Novel Insights into the Molecular Mechanisms Involved in the Neuroprotective Effects of C-Phycocyanin against Brain Ischemia in Rats.

Ischemic stroke produces a large health impact worldwide, with scarce therapeutic options. This study aimed to reveal the role of NADPH oxidase and neuroinflammatory genes in the cerebral anti-ischemic effects of C-Phycocyanin (C-PC), the chief biliprotein of Spirulina platensis. Rats with either focal cerebral ischemia/reperfusion (I/R) or acute brain hypoperfusion, received C-PC at different doses, or a vehicle, for up to 6 h post-stroke. Neurological, behavioral and histochemical parameters were assessed in I/R rats at 24 h. Cerebral gene expression and hippocampal neuron viability were evaluated in hypoperfused rats at acute (24 h) or chronic phases (30 days), respectively. A molecular docking analysis of NOX2 and C-PC-derived Phycocyanobilin (PCB) was also performed. C-PC, obtained with a purity of 4.342, significantly reduced the infarct volume and neurological deficit in a dose-dependent manner, and improved the exploratory activity of I/R rats. This biliprotein inhibited NOX2 expression, a crucial NADPH oxidase isoform in the brain, and the superoxide increase produced by the ischemic event. Moreover, C-PC-derived PCB showed a high binding affinity in silico with NOX2. C-PC downregulated the expression of pro-inflammatory genes (IFN-γ, IL-6, IL-17A, CD74, CCL12) and upregulated immune suppressive genes (Foxp3, IL-4, TGF-β) in hypoperfused brain areas. This compound also decreased chronic neuronal death in the hippocampus of hypoperfused rats. These results suggest that the inhibition of cerebral NADPH oxidase and the improvement of neuroinflammation are key mechanisms mediating the neuroprotective actions of C-PC against brain ischemia.

Euphorbia supina Extracts Block NADPH Oxidase-Mediated, Ceramide-Induced Apoptosis Initiated by Diesel Particulate Matter.

Air pollutants contribute to the development of diseases such as asthma, chronic obstructive pulmonary disease (COPD), pulmonary cancer, cardiovascular problems, and some skin diseases. We recently found that a major air pollutant, diesel particulate matter (DPM), induces apoptosis in human keratinocytes by increasing a proapoptotic lipid mediator, ceramide. DPM activates nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX), which stimulates sphingomyelinase, leading to an increased conversion of sphingomyelin to ceramide. Interestingly, we characterized that although NOX is a reactive oxygen species (ROS) generator, the activation of sphingomyelinases by NOX is an ROS-independent mechanism. A Korean weed, prostrate spurge Euphorbia supina Rafin (ESR), has been used for centuries as a folk medicine to treat bronchitis, hepatitis, hemorrhage, and skin inflammation. Flavonoids, terpenes and tannins are enriched in ESR, and although ESR has proven antioxidative activity, its biological activities are largely unknown. Here, we investigate whether and how ESR protects keratinocytes against DPM-mediated apoptosis. We found that ESR-extracts (ESR-Ex) protect keratinocytes from DPM-induced apoptosis by inhibiting NOX activation in keratinocytes in response to DPM. We also demonstrated that ESR-Ex suppresses NOX activation via a blockage of the aryl hydrocarbon receptor (AhR) activation-mediated transcription of neutrophil cytosolic factor 1 (NCF1)/p47phox, a subunit of NOX. Our study reveals previously uncharacterized biological activity of ESR-Ex; i.e., its inhibition of Ahr and NOX activation. Thus, because the inhibition of NOX has already been developed to treat NOX-mediated diseases, including various types of cardiovascular diseases and cancers, initiated by air pollutants and because AhR activation contributes to the development of chronic inflammatory diseases, our study provides further advantages for the medical use of ESR.

Context-specific effects of NOX4 inactivation in acute myeloid leukemia (AML)

PurposeOxidative stress has been linked to initiation and progression of cancer and recent studies have indicated a potential translational role regarding modulation of ROS in various cancers, including acute myeloid leukemia (AML). Detailed understanding of the complex machinery regulating ROS including its producer elements in cancer is required to define potential translational therapeutic use. Based on previous studies in acute myeloid leukemia (AML) models, we considered NADPH oxidase (NOX) family members, specifically NOX4 as a potential target in AML.MethodsPharmacologic inhibition and genetic inactivation of NOX4 in murine and human models of AML were used to understand its functional role. For genetic inactivation, CRISPR-Cas9 technology was used in human AML cell lines in vitro and genetically engineered knockout mice for Nox4 were used for deletion of Nox4 in hematopoietic cells via Mx1-Cre recombinase activation.ResultsPharmacologic NOX inhibitors and CRISPR-Cas9-mediated inactivation of NOX4 and p22-phox (an essential NOX component) decreased proliferative capacity and cell competition in FLT3-ITD-positive human AML cells. In contrast, conditional deletion of Nox4 enhanced the myeloproliferative phenotype of an FLT3-ITD induced knock-in mouse model. Finally, Nox4 inactivation in normal hematopoietic stem and progenitor cells (HSPCs) caused a minor reduction in HSC numbers and reconstitution capacity.ConclusionThe role of NOX4 in myeloid malignancies appears highly context-dependent and its inactivation results in either enhancing or inhibitory effects. Therefore, targeting NOX4 in FLT3-ITD positive myeloid malignancies requires additional pre-clinical assessment.

Aqueous Thunbergia laurifolia leaf extract alleviates paraquat-induced lung injury in rats by inhibiting oxidative stress and inflammation

BackgroundParaquat (PQ) has been reported to have a high mortality rate. The major target organ of PQ poisoning is the lungs. The pathogenesis of PQ-induced lung injury involves oxidative stress and inflammation. Unfortunately, there is still no effective antidote for PQ poisoning. We hypothesized that aqueous Thunbergia laurifolia (TL) leaf extract is a possible antidote for PQ-induced lung injury.MethodsThe total phenolic content and caffeic acid content of an aqueous extract of TL leaves were analyzed. Male Wistar rats were randomly divided into four groups (n = 4 per group): the control group (administered normal saline), the PQ group (administered 18 mg/kg body weight (BW) PQ dichloride subcutaneously), the PQ + TL-low-dose (LD) group (administered PQ dichloride subcutaneously and 100 mg/kg BW aqueous TL leaf extract by oral gavage) and the PQ + TL-high-dose (HD) group (administered PQ dichloride subcutaneously and 200 mg/kg BW aqueous TL leaf extract by oral gavage). Malondialdehyde (MDA) levels and lung histopathology were analyzed. In addition, the mRNA expression of NADPH oxidase (NOX), interleukin 1 beta (IL-1β), and tumor necrosis factor alpha (TNF-α) was assessed using reverse transcription-polymerase chain reaction (RT-PCR), and the protein expression of IL-1β and TNF-α was analyzed using immunohistochemistry.ResultsThe total phenolic content of the extract was 20.1 ± 0.39 μg gallic acid equivalents (Eq)/mg extract, and the caffeic acid content was 0.31 ± 0.01 μg/mg. The PQ group showed significantly higher MDA levels and NOX, IL-1β and TNF-α mRNA expression than the control group. Significant pathological changes, including alveolar edema, diffuse alveolar collapse, hemorrhage, leukocyte infiltration, alveolar septal thickening and vascular congestion, were observed in the PQ group compared with the control group. However, the aqueous TL leaf extract significantly attenuated the PQ-induced increases in MDA levels and NOX, IL-1β and TNF-α expressions. Moreover, the aqueous TL leaf extract ameliorated PQ-induced lung pathology.ConclusionThis study indicates that aqueous TL leaf extract can ameliorate PQ-induced lung pathology by modulating oxidative stress through inhibition of NOX and by regulating inflammation through inhibition of IL-1β and TNF-α expressions. We suggest that aqueous TL leaf extract can be used as an antidote for PQ-induced lung injury.

Diphenyleneiodonium efficiently inhibits the characteristics of a cancer stem cell model derived from induced pluripotent stem cells.

Diphenyleneiodonium (DPI) has long been evaluated as an anticancer drug inhibiting NADPH oxidase, the IC50 in several cancer cell lines was reported 10 µM, which is too high for efficacy. In this study, we employed miPS-Huh7cmP cells, which we previously established as a cancer stem cell (CSC) model from induced pluripotent stem cells, to reevaluate the efficacy of DPI because CSCs are currently one of the main foci of therapeutic strategy to treat cancer, but generally considered resistant to chemotherapy. As a result, the conventional assay for the cell growth inhibition by DPI accounted for an IC50 at 712 nM that was not enough to define the effectiveness as an anticancer drug. Simultaneously, the wound-healing assay revealed an IC50 of approximately 500 nM. Comparatively, the IC50 values shown on sphere formation, colony formation, and tube formation assays were 5.52, 12, and 8.7 nM, respectively. However, these inhibitory effects were not observed by VAS2780, also a reputed NADPH oxidase inhibitor. It is noteworthy that these three assays are evaluating the characteristic of CSCs and are designed in the three-dimensional (3D) culture methods. We concluded that DPI could be a suitable candidate to target mitochondrial respiration in CSCs. We propose that the 3D culture assays are more efficient to screen anti-CSC drug candidates and better mimic tumor microenvironment when compared to the adherent monolayer of 2D culture system used for a conventional assay, such as cell growth inhibition and wound-healing assays.

RIP3-Dependent Accumulation of Mitochondrial Superoxide Anions in TNF-α-Induced Necroptosis.

Excessive production of reactive oxygen species (ROS) is a key phenomenon in tumor necrosis factor (TNF)-α-induced cell death. However, the role of ROS in necroptosis remains mostly elusive. In this study, we show that TNF-α induces the mitochondrial accumulation of superoxide anions, not H2O2, in cancer cells undergoing necroptosis. TNF-α-induced mitochondrial superoxide anions production is strictly RIP3 expression-dependent. Unexpectedly, TNF-α stimulates NADPH oxidase (NOX), not mitochondrial energy metabolism, to activate superoxide production in the RIP3-positive cancer cells. In parallel, mitochondrial superoxide-metabolizing enzymes, such as manganese-superoxide dismutase (SOD2) and peroxiredoxin III, are not involved in the superoxide accumulation. Mitochondrial-targeted superoxide scavengers and a NOX inhibitor eliminate the accumulated superoxide without affecting TNF-α-induced necroptosis. Therefore, our study provides the first evidence that mitochondrial superoxide accumulation is a consequence of necroptosis.

Lycopene Inhibits IL-6 Expression by Upregulating NQO1 and HO-1 via Activation of Nrf2 in Ethanol/Lipopolysaccharide-Stimulated Pancreatic Acinar Cells.

In alcoholic pancreatitis, alcohol increases gut permeability, which increases the penetration of endotoxins, such as lipopolysaccharides (LPS). LPS act as clinically significant triggers to increase pancreatic damage in alcoholic pancreatitis. Ethanol or LPS treatment increases reactive oxygen species (ROS) production in pancreatic acinar cells. ROS induce inflammatory cytokine production in pancreatic acinar cells, leading to pancreatic inflammation. The nuclear erythroid-2-related factor 2 (Nrf2) pathway is activated as a cytoprotective response to oxidative stress, and induces the expression of NAD(P)H quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1). Lycopene exerts anti-inflammatory and antioxidant effects in various cells. We previously showed that lycopene inhibits NADPH oxidase to reduce ROS and IL-6 levels, and zymogene activation in ethanol or palmitoleic acid-treated pancreatic acinar cells. In this study, we examined whether lycopene inhibits IL-6 expression by activating the Nrf2/NQO1-HO-1 pathway, and reducing intracellular and mitochondrial ROS levels, in ethanol and LPS-treated pancreatic AR42J cells. Lycopene increased the phosphorylated and nuclear-translocated Nrf2 levels by decreasing the amount of Nrf2 sequestered in the cytoplasm via a complex formation with Kelch-like ECH1-associated protein 1 (Keap1). Using exogenous inhibitors targeting Nrf2 and HO-1, we showed that the upregulation of activated Nrf2 and HO-1 results in lycopene-induced suppression of IL-6 expression and ROS production. The consumption of lycopene-rich foods may prevent the development of ethanol and LPS-associated pancreatic inflammation by activating Nrf2-mediated expression of NQO1 and HO-1, thereby decreasing ROS-mediated IL-6 expression in pancreatic acinar cells.

Papel de Passiflora edulis (maracuyá) en el control de la presión arterial: posibles mecanismos moleculares

Passiflora edulis (passion fruit) is a plant whose fruit has a high biological value as it contains a large amount of polyphenols, the most important of which are flavonoids that act as powerful antioxidants against cancer and cardiovascular diseases. Recent studies have highlighted its antihypertensive role, even comparing it to hypotensive drugs. Arterial hypertension is one of the diseases that causes the greatest mortality and the most widespread worldwide. It is caused by endothelial dysfunction between vascular constrictor and relaxant factors, as a result of oxidative stress caused by the overproduction of reactive oxygen species. Flavonoids reduce the formation of free radicals by inhibiting NADPH oxidase; they also increase the activity of nitric oxide synthase (eNOS), increasing the vasodilation promoted by nitric oxide and providing a response capacity to endothelial damage by increasing intracellular calcium, which further stimulates vasodilation. They also exert a diuretic action and significantly increase urine flow, glomerular filtration and Na+ and K+ excretion. This diuretic effect, added to the antioxidant effect, would explain the plant's antihypertensive activity.

Outgrowth endothelial progenitor cells restore cerebral barrier function following ischaemic damage: The impact of NOX2 inhibition.

Disruption of blood-brain barrier (BBB), formed mainly by human brain microvascular endothelial cells (HBMECs), constitutes the major cause of mortality following ischaemic stroke. This study investigates whether OECs (outgrowth endothelial cells) can restore BBB integrity and function following ischaemic damage and how inhibition of NOX2, a main source of vascular oxidative stress, affects the characteristics of BBB established with OECs and HBMECs in ischaemic settings. In vitro models of human BBB were constructed by co-culture of pericytes and astrocytes with either OECs or HBMECs before exposure to oxygen-glucose deprivation (OGD) alone or followed by reperfusion (OGD + R) in the absence or presence of NOX2 inhibitor, gp91ds-tat. The function and integrity of BBB were assessed by measurements of paracellular flux of sodium fluorescein (NaF) and transendothelial electrical resistance (TEER), respectively. Treatment with OECs during OGD + R effectively restored BBB integrity and function. Compared to HBMECs, OECs possessed lower NADPH oxidase activity, superoxide anion levels and had greater total antioxidant capacity during OGD and OGD + R. Inhibition of NADPH oxidase during OGD and OGD + R restored the integrity and function of BBB established by HBMECs. This was evidenced by reductions in NADPH oxidase activity and superoxide anion levels. In contrast, treatment with gp91ds-tat aggravated ischaemic injury-induced BBB damage constructed by OECs. In conclusion, OECs are more resistant to ischaemic conditions and can effectively repair cerebral barrier following ischaemic damage. Suppression of oxidative stress through specific targeting of NOX2 requires close attention while using OECs as therapeutics.

Inhibition of the NADPH Oxidase Pathway Reduces Ferroptosis during Septic Renal Injury in Diabetic Mice.

Background Obesity and type 2 diabetes mellitus (DM) contribute to a higher mortality rate in patients with septic acute kidney injury (AKI) during sepsis. Reactive oxygen species (ROS) is the major injury factor for sepsis. This study was aimed at exploring the potential therapeutic drug for septic AKI targeting on ROS. Methods A murine septic AKI model was established in both wild-type and high-fat diet-fed (HFD) mice. NADPH oxidase inhibitor Vas2870 was used in vivo to explore the role of NADPH oxidase in ROS release in septic AKI in diabetic mice. Ferrostatin-1 was administered to investigate the role of ferroptosis in ROS accumulation during NADPH oxidase activating in septic AKI in diabetic mice. Results Compared to chow diet-fed mice, HFD diabetic mice which were subjected to LPS exhibited aggravated renal function (blood urea nitrogen, creatinine clearance, and serum cystatin C) and oxidative stress (malondialdehyde, 4-HNE, ROS, 8-OHdG, and NADPH oxidase), thus resulting in a higher mortality rate. Septic renal injury was significantly attenuated by the ferroptosis inhibitor Fer-1 in HFD-challenged mice. Furthermore, ferroptosis accumulation and related protein expression (ASCL4, FTH1, and GPX4) were altered by LPS stimulation in HFD-challenged mice and suppressed by NADPH oxidase inhibition via Vas2870 in vivo. In summary, NADPH inhibition restored septic renal function from injury by suppressing ferroptosis accumulation in HFD-challenged mice. Conclusion These results suggest that targeting NADPH-mediated ROS release and ferroptosis accumulation is a novel therapeutic strategy to protect the kidney from septic injury in patients with obesity and type 2 DM.

Identification of Resolvin D1 and Protectin D1 as Potential Therapeutic Agents for Treating Kidney Stones.

Intrarenal calcium oxalate (CaOx) crystals induce renal tubular epithelial cell (TEC) inflammatory and oxidative injury. This study is aimed at exploring potential therapeutic lipid components in kidney stones because lipids are involved in the development of several diseases and indicate the risk of kidney stones. Serum specimens were collected from 35 kidney stone patients and 35 normal controls. The lipid components in serum were measured, and differences were analyzed. The documented biological importance was comprehensively reviewed to identify lipids that differed significantly between the two groups to find potential agents associated with kidney stones. CaOx nephrocalcinosis mouse model was established to examine the therapeutic effects of specific lipids on CaOx deposition and CaOx-induced oxidative renal injury. Several lipids with significantly different levels were present in the serum of patients with stones and normal controls. Resolvin D1 (RvD1) (4.93-fold change, P < 0.001) and protectin D1 (PD1) (5.06-fold change, P < 0.001) were significantly decreased in the serum of patients with kidney stones, and an integrative review suggested that these factors might be associated with inflammatory responses, which is a crucial mechanism associated with stone damage. The administration of RvD1 and PD1 significantly inhibited kidney CaOx deposition and suppressed CaOx-induced renal tubular cell inflammatory injury and necrosis in a CaOx nephrocalcinosis mouse model. Furthermore, RvD1 and PD1 facilitated the expression of the oxidative indicator superoxide dismutase 2 (SOD2), inhibited NADPH oxidase 2 (NOX2) expression, and diminished intracellular reactive oxygen species (ROS) levels. This study preliminarily elucidated the role of lipids in kidney stones. The inhibitory effects of RvD1 and PD1 on oxidative damage induced by CaOx deposition provide a promising perspective for kidney stone treatment strategies.

Silica nanoparticles induce pyroptosis and cardiac hypertrophy via ROS/NLRP3/Caspase-1 pathway

Growing literatures suggest that silica nanoparticles (SiNPs) exposure is correlated with adverse cardiovascular effects. Cardiac hypertrophy is one of the most common risk factors for heart failure. However, whether SiNPs involved in cardiac hypertrophy and the underlying mechanisms was remained unexploited. Our study aimed to investigate the molecular mechanisms of SiNPs on pyroptosis and cardiac hypertrophy. The in vivo results found that SiNPs induced ultrastructural change and histopathological damage, accompanied by oxidative damage occurred and increased levels of inflammatory factors (IL-18 and IL-1β) in heart tissue. In addition, SiNPs could upregulate the expressions of cardiac hypertrophy-related special marker including ANP, BNP, β-MHC, it also elevated the pyroptosis-related protein, such as NLRP3, Cleaved-Caspase-1, GSDMD, IL-18 and Cleaved-IL-1β in vivo. For in vitro study, SiNPs increased the intracellular ROS generation and activated the NLRP3/Caspase-1/GSDMD signaling pathway in cardiomyocytes. Whereas, the NADPH oxidase (NOX) inhibitor VAS2870 had effectively inhibited the ROS level and suppressed the expression of NLRP3, ASC, Pro-Caspase-1, Cleaved-Caspase-1, N-GSDMD, IL-18, Cleaved-IL-1β, ANP, BNP and β-MHC. Moreover, transfected with si-NLRP3 or adopted with Caspase-1 inhibitor VX-765 in cardiomyocytes showed an inhibitory effect on SiNPs-induced pyroptosis and cardiac hypertrophy. In summary, our results demonstrated that SiNPs could trigger pyroptosis and cardiac hypertrophy via ROS/NLRP3/Caspase-1 signaling pathway.

Osteocrin alleviates cardiac hypertrophy via attenuating oxidative stress

Osteocrin (OSTN) is a secretory peptide mainly derived from the skeletal muscles and bones. The present study aims to explore the role of OSTN in cardiac hypertrophy and its underlying mechanism. Experiments were carried out in mice receiving angiotensin (Ang) II to induce cardiac hypertrophy, and in neonatal rat cardiomyocytes (NRCMs) or human cardiac AC16 cells with Ang II-induced cardiomyocytes hypertrophy. The expression of OSTN was lower in Ang II-treated mouse heart of mice, NRCMs and AC16 cells. OSTN overexpression attenuated the hypertrophy and fibrosis of heart in mice induced by Ang II. Overexpression of OSTN inhibited hypertrophy of NRCMs and AC16 cells induced by Ang II. Increased oxidative stress was observed in the heart of mice, NRCMs and AC16 cells treated with Ang II. Overexpression of NADPH oxidase 1 (Nox1) reversed the attenuating effects of OSTN on the Ang II-induced hypertrophic cardiomyocytes. Treatment with NADPH oxidase inhibitor apocynin (APO) suppressed the hypertrophy of NRCMs and AC16 cells induced by Ang II. The above findings suggested OSTN upregulation could attenuate cardiac hypertrophy and fibrosis. The upregulation of OSTN could alleviate hypertrophy of cardiomyocytes via suppressing oxidative stress.