Nox-derived Reactive Oxygen Species Research Articles

Methods for Detection of NOX-Derived Superoxide Radical Anion and Hydrogen Peroxide in Cells.

NADPH oxidases (NOX) are transmembrane enzymes, which catalyze the formation of reactive oxygen species (ROS). In humans and most mammals, the NOX family comprises seven members, namely, NOX1-5 and the dual oxidases DUOX1 and 2. The primary product of most NOX isoforms is the superoxide radical anion O2ċ-, which is rapidly dismutated in hydrogen peroxide (H2O2), while NOX4 and DUOX mostly generate H2O2. ROS are multifunctional molecules in tissues, and NOX-derived ROS cellular functions are as diverse as microbial killing (NOX2), thyroid hormone synthesis (DUOX2), or otoconia formation in the inner ear (NOX3). NOX are potential pharmacological targets in numerous diseases such as diabetes, fibrosis, and brain ischemia, and NOX inhibitors are currently under development. Here we describe two cellular assays to detect extracellular O2ċ- and H2O2 in cells overexpressing specific NOX isoforms and their subunits.

Novel crosstalk between Vps26a and Nox4 signaling during neurogenesis

Despite numerous studies on the molecular switches governing the conversion of stemness to differentiation in embryonic stem cells (ESCs), little is known about the involvement of the retromer complex. Under neural differentiation conditions, Vps26a deficiency (Vps26a-/-) or knockdown suppressed the loss of stemness and subsequent neurogenesis from ESCs or embryonic carcinoma cells, respectively, as evidenced by the long-lasting expression of stemness markers and the slow appearance of neuronal differentiation markers. Interestingly, relatively low reactive oxygen species (ROS) levels were generated during differentiation of Vps26a-/- ESCs, and treatment with an antioxidant or inhibitor of NADPH oxidase (Nox), a family of ROS-generating enzymes, led to restoration of stemness in wild-type cells to the level of Vps26a-/- cells during neurogenesis. Importantly, a novel interaction between Vps26a and Nox4 linked to the activation of ERK1/2 depended highly on ROS levels during neurogenesis, which were strongly suppressed in differentiating Vps26a-/- ESCs. Moreover, inhibition of phosphorylated ERK1/2 (pERK1/2) resulted in decreased ROS and Nox4 levels, indicating the mutual dependency between pERK1/2 and Nox4-derived ROS during neurogenesis. These results suggest that Vps26a regulates stemness by actively cooperating with the Nox4/ROS/ERK1/2 cascade during neurogenesis. Our findings have important implications for understanding the regulation of stemness via crosstalk between the retromer molecule and redox signaling, and may contribute to the development of ESC-based therapeutic strategies for the mass production of target cells.

NOX2 inhibition reduces oxidative stress and prolongs survival in murine KRAS-induced myeloproliferative disease

Mutations leading to constitutive RAS activation contribute in myeloid leukemogenesis. RAS mutations in myeloid cells are accompanied by excessive formation of reactive oxygen species (ROS), but the source of ROS and their role for the initiation and progression of leukemia have not been clearly defined. To determine the role of NOX2-derived ROS in RAS-driven leukemia, double transgenic LSL-KrasG12D × Mx1-Cre mice expressing oncogenic KRAS in hematopoietic cells (M-KrasG12D) were treated with Nα-methyl-histamine (NMH) that targeted the production of NOX2-derived ROS in leukemic cells by agonist activity at histamine H2 receptors. M-KrasG12D mice developed myeloid leukemia comprising mature CD11b+Gr1+ myeloid cells that produced NOX2-derived ROS. Treatment of M-KrasG12D mice with NMH delayed the development of myeloproliferative disease and prolonged survival. In addition, NMH-treated M-KrasG12D mice showed reduction of intracellular ROS along with reduced DNA oxidation and reduced occurence of double-stranded DNA breaks in myeloid cells. The in vivo expansion of leukemia was markedly reduced in triple transgenic mice where KRAS was expressed in hematopoietic cells of animals with genetic NOX2 deficiency (Nox2−/− × LSL-KrasG12D × Mx1-Cre). Treatment with NMH did not alter in vivo expansion of leukemia in these NOX2-deficient transgenic mice. We propose that NOX2-derived ROS may contribute to the progression of KRAS-induced leukemia and that strategies to target NOX2 merit further evaluation in RAS-mutated hematopoietic cancer.

NOX1-derived ROS drive the expression of Lipocalin-2 in colonic epithelial cells in inflammatory conditions.

Inflammatory bowel disease (IBD) is characterized by severe and recurrent inflammation of the gastrointestinal tract, associated with altered patterns of cytokine synthesis, excessive reactive oxygen species (ROS) production, and high levels of the innate immune protein, lipocalin-2 (LCN-2), in the mucosa. The major source of ROS in intestinal epithelial cells is the NADPH oxidase NOX1, which consists of the transmembrane proteins, NOX1 and p22PHOX, and the cytosolic proteins, NOXO1, NOXA1, and Rac1. Here, we investigated whether NOX1 activation and ROS production induced by key inflammatory cytokines in IBD causally affects LCN-2 production in colonic epithelial cells. We found that the combination of TNFα and IL-17 induced a dramatic upregulation of NOXO1 expression that was dependent on the activation of p38MAPK and JNK1/2, and resulted into an increase of NOX1 activity and ROS production. NOX1-derived ROS drive the expression of LCN-2 by controlling the expression of IκBζ, a master inducer of LCN-2. Furthermore, LCN-2 production and colon damage were decreased in NOX1-deficient mice during TNBS-induced colitis. Finally, analyses of biopsies from patients with Crohn's disease showed increased JNK1/2 activation, and NOXO1 and LCN-2 expression. Therefore, NOX1 might play a key role in mucosal immunity and inflammation by controlling LCN-2 expression.

The role of NOX2-derived reactive oxygen species in collagenase-induced osteoarthritis

Synovitis in collagenase-induced osteoarthritis (CiOA) is driven by locally released S100A8/A9 proteins and enhances joint destruction. S100A8/A9 can induce reactive oxygen species (ROS) release by phagocytes in OA synovium via neutrophil cytosolic factor-1 (Ncf1)-regulated NOX2 activation. In the present study we investigated whether NOX2-derived ROS affect joint pathology during CiOA. CiOA was induced in knee joints of wild type (WT) and Ncf1-deficient (Ncf1**) mice. Synovial gene expression of NOX2-subunits was measured with quantitative real-time polymerase chain reaction (qRT-PCR). Joint pathology was assessed using histology and immunohistochemistry for aggrecan neo-epitope VDIPEN. Levels of inflammatory proteins were measured with Luminex or ELISA. Phagocytes in synovium, blood, bone marrow (BM) and spleen were analyzed with flow cytometry. ROS release by phagocytes was measured with a ROS detection kit. CiOA induction in knee joints of WT mice caused significantly increased synovial gene expression of NOX2 subunits. On day 7 of CiOA, cartilage damage and MMP activity, as measured by VDIPEN, were comparable between WT and Ncf1** mice. Synovial thickening, synovial S100A8/A9 levels and percentages of synovial macrophages, polymorphonuclear cells (PMNs), and monocytes were not different, as were levels of inflammatory mediators in serum and phagocyte percentages in blood, BM and spleen. On day 42 of CiOA, synovitis, cartilage damage, and osteophyte formation in Ncf1** mice were unaltered when compared to WT mice. ROS detection confirmed that Ncf1** PMNs lack functional NOX2, but invitro macrophages showed ROS production, suggesting activation of compensatory mechanisms. Absence of Ncf1-mediated ROS production does not alter joint pathology in CiOA.

Abstract 123: Effect of Immune Cell-Derived Reactive Oxygen Species on Dahl SS Hypertension

Previous studies utilizing the SS p67 phox–/– rat have demonstrated the importance of systemic NADPH oxidase NOX2-derived reactive oxygen species (ROS) production in the pathogenesis of Dahl Salt-Sensitive (SS) hypertension and renal damage. Our laboratory has established a key role for renal immune cell infiltration in the development of SS hypertension and observed an enrichment of NOX2 subunits in infiltrating T cells. The contribution of ROS specifically derived from immune cells in SS hypertension remains unknown. To assess the role of ROS in immune cells, SS p67 phox–/– rats underwent total body irradiation and received bone marrow transfer from either SS p67 phox–/– (p67/p67) or SS (p67/SS) donor rats. p67/SS rats would be capable of producing NOX2-derived ROS only in the transferred SS cells of hematopoietic origin while the p67/p67 control group would be unable to produce NOX2-derived ROS globally. Mean arterial pressure (MAP) was not different between the p67/SS and p67/p67 rats when fed a 0.4% NaCl diet (112.6±1.4 vs 110.7±2.4 mmHg, n=4-5). After 3 weeks of high salt, however, there was a significantly greater increase in MAP in the p67/SS rats (176.1±4.7 mmHg) compared to the p67/p67 control rats (147.9±8.4 mmHg), which was accompanied by a significant increase in albuminuria (230.3±13.9 vs 153.1±14.9 mg/day, p67/SS vs p67/p67, n=5-6). Interestingly, upon analysis of the immune cells in the kidney, no differences were detected in the number of CD45+ total leukocytes, CD11b/c+ monocytes/macrophages, CD3+ T cells, and CD45R+ B cells between the p67/SS and p67/p67 (n=4-5), indicating that the recruitment of immune cells into the kidney during hypertension and renal damage is independent of NOX2-derived ROS production from the renal parenchyma. The respiratory burst response to phorbol 12-myristate 13-acetate stimulus (135 μM) in peritoneal macrophages isolated from p67/SS was 4.0-fold greater compared to nonresponsive p67/p67 cells, and was completely inhibited by superoxide dismutase, demonstrating that the reconstituted bone marrow cells in the p67/SS are capable of producing superoxide. In summary, the production of NOX2-derived ROS from immune cells alone is sufficient for the development of Dahl SS hypertension and renal damage.

Abstract 040: Vascular Dysfunction and Androgen Deficiency - Insights From Children With Hypospadias

Background: Hypospadias in boys may be associated with a lack of androgen exposure during the masculinisation programming window. As testosterone has effects on the vasculature, we assessed whether boys with hypospadias show any evidence of vascular dysfunction. Methods: Excess foreskin tissue was obtained from boys undergoing hypospadias repair (cases) or circumcision (controls) and small arteries dissected from this tissue. Vascular contractility was assessed by wire myography in response to U46619 (thromboxane A2 analogue). Vascular smooth muscle cells (VSMCs) were cultured and generation of reactive oxygen species (ROS) was measured by amplex red and chemiluminescence. NADPH oxidase (Nox) mRNA expression was measured by qPCR. Results: 19 cases and 22 age-matched controls were enrolled in this study (median age 1.9 (range 1.3,12.2) years). There were no differences in clinical cardiometabolic or biochemical parameters between the cases and controls. Arteries from cases demonstrated increased constriction to U46619 compared to controls (Emax 175.6 vs 66.3 p<0.001), an effect inhibited by the ROS scavenger N-acetylcysteine (NAC). VSMC superoxide anion (5.3 fold) production and H 2 0 2 (3.3 fold) levels were increased in cases compared to controls (p<0.05). Expression of Nox5, a major ROS-generating oxidase in vascular cells, was increased in cases (2.6 fold,p<0.05). Exposure of vessels to testosterone increased vasoconstriction to U46619 (Emax 66.3 to 124.6 p<0.001) in controls, but not in cases. Incubation with NAC abolished the testosterone-induced vascular effects. Vascular hypercontractility in boys with hypospadias was associated with reduced endothelium-dependent and -independent vasorelaxation, compared with controls. Conclusions: These novel data, from a unique cohort of patients, demonstrate that small arteries from boys with hypospadias exhibit increased vascular contractility and decreased vasorelaxation with associated increased Nox-derived ROS generation. The functional significance of vascular dysfunction in these boys is unclear but may play a role in immediate surgical outcome as well as altered long-term cardiovascular risk.

Abstract P143: Nox1 Elicits Endothelial Cell Proliferation in a CREB- and Ref-1- Dependent Manner

Pulmonary arterial hypertension (PAH) is a complex and progressive disorder, characterized by an increase in vascular remodeling, a rise in pulmonary arterial pressure and right heart failure. Recently, we and others showed that BMP antagonist Gremlin1 elicits pulmonary endothelial cell (EC) proliferation in response to hypoxia and that Gremlin1 haplodeficiency attenuates PAH. NADPH oxidase (Nox)-derived reactive oxygen species (ROS) seem to play a pivotal role in PAH. However, the mechanisms by which ROS propagates the disease are unclear. Transcription factor CREB, which is activated by hypoxia, ROS, and interaction with Ref-1 (redox factor 1), mediates gene transcription related to proliferation and vascular remodeling. We postulated that Nox1/Ref-1-mediated CREB activation leads to Gremlin1-induced EC proliferation. Human pulmonary arterial EC (HPAECs, Lonza) were subjected to 24 hr hypoxia (1% O 2 vs. normoxia - 21% O 2 ) to mimic the EC phenotype in PAH. Hypoxia upregulated Nox1 protein level (1.40±0.09-fold, p<0.05) and H 2 O 2 production level/mg protein (2.20±0.21-fold, p<0.0001) vs. normoxia. siNox1 (Nox1 gene silencing) abolished hypoxia-induced Nox1, and Nox1 inhibitor, NoxA1ds, decreased hypoxia-promoted H 2 O 2 . Moreover, siNox1 decreased hypoxia-induced pCREB (1.74±0.22-fold v. normoxia, vs. 1.07±0.08 siNox1+hypoxia, p<0.05), and siCREB decreased hypoxia-induced Gremlin1 (1.83±0.16 hypoxia vs. 0.35±0.01 siCREB+hypoxia, p<0.05). Further, hypoxia augmented nuclear pCREB/Ref-1 interaction (1.812±0.207-fold vs. normoxia, p<0.05) and pCREB association with its DNA binding motif. siRNA for Ref-1 impaired hypoxia-induced pCREB DNA binding (1.96±0.06 hypoxia vs. 0.815±0.219 siRef-1+hypoxia, p<0.01). Moreover, siCREB decreased hypoxia-induced EC proliferation (1.40±0.050 hypoxia vs. 0.96±0.04 siCREB+hypoxia). Finally, preliminary data show pCREB binding to the Gremlin1 promoter. Taken together, our data support a previously unidentified redox signaling pathway by which Nox1-derived ROS promote Gremlin1 expression and EC proliferation in PAH.

Antitumor activity of BJ-1207, a 6-amino-2,4,5-trimethylpyridin-3-ol derivative, in human lung cancer

Enhanced expression of NADPH oxidase (NOX) and the subsequent production of reactive oxygen species (ROS) are associated with lung cancer. In the present study, fifty 6-amino-2,4,5-trimethylpyridin-3-ol derivatives were screened for anticancer activity by targeting NOX2-derived ROS. The compounds suppressed ROS production and decreased cancer cell viability (R2 = 0.79). Among the derivatives, the compound coded BJ-1207, which contained a 4-(hydroxydiphenylmethyl)piperidine moiety, exhibited the most effective anticancer activity against A549 lung cancer cell line and eight other cancer cell lines, including H1299, MCF-7, MDA-MB-231, HT-29, SW620, Mia PaCa-2, PANC-1, and U937. BJ-1207 also showed significantly lower inhibitory effects on kinase insert domain receptor (KDR) and c-KIT tyrosine kinase but higher inhibitory activity on NOX than those of sunitinib, a multi-receptor tyrosine kinase (RTK) inhibitor. In addition, BJ-1207-induced inhibition of RTK-downstream signaling pathways, such as ROS production, and expression of target genes, such as stem cell factor and transforming growth factor-α, were similar to those induced by sunitinib. In the xenograft chick tumor model, BJ-1207 inhibited lung tumor growth to a similar or much greater extent than that of sunitinib or cisplatin, respectively. Overall, the present study showed that BJ-1207, a vitamin B6-derived 2,4,5-trimethylpyridin-3-ol compound with azacyclonol moiety at C (6)-position of the pyridine ring, inhibited NOX activity and that it is a promising lead compound for developing anticancer drugs against lung cancer.

NOX4 expression and distal arteriolar remodeling correlate with pulmonary hypertension in COPD

BackgroundPulmonary hypertension (PH) in chronic obstructive pulmonary disease (COPD) is suggested as the consequence of emphysematous destruction of vascular bed and hypoxia of pulmonary microenvironment, mechanisms underpinning its pathogenesis however remain elusive. The dysregulated expression of nicotinamide adenine dinucleotide phosphate (NADPH)-oxidases and superoxide generation by pulmonary vasculatures have significant implications in the hypoxia-induced PH.MethodsIn this study, the involvement of NADPH oxidase subunit 4 (NOX4) in pulmonary arteriolar remodeling of PH in COPD was investigated by ascertaining the morphological alteration of pulmonary arteries and pulmonary blood flow using cardiac magnetic resonance imaging (cMRI), and the expression and correlation of NOX4 with pulmonary vascular remodeling and pulmonary functions in COPD lungs.ResultsResults demonstrated that an augmented expression of NOX4 was correlated with the increased volume of pulmonary vascular wall in COPD lung. While the volume of distal pulmonary arteries was inversely correlated with pulmonary functions, despite it was positively associated with the main pulmonary artery distensibility, right ventricular myocardial mass end-systolic and right ventricular myocardial mass end-diastolic in COPD. In addition, an increased malondialdehyde and a decreased superoxide dismutase were observed in sera of COPD patients. Mechanistically, the abundance of NOX4 and production of reactive oxygen species (ROS) in pulmonary artery smooth muscle cells could be dynamically induced by transforming growth factor-beta (TGF-β), which in turn led pulmonary arteriolar remodeling in COPD lungs.ConclusionThese results suggest that the NOX4-derived ROS production may play a key role in the development of PH in COPD by promoting distal pulmonary vascular remodeling.

Abstract 441: NOX2 inhibition reduces oxidative stress and prolongs survival of mice with Kras induced myeloproliferative disease

Abstract 0 0 1 300 1716 University of Gothenburg 14 4 2012 14.0 Normal 0 false false false SV JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; line-height:107%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:SV;} Mutations leading to Ras gene activation are important contributors to myeloid leukemogenesis. Kras is one of three homologues of the Ras family, and oncogenic Kras is frequently found in monocytic forms of acute myeloid leukemia (AML), chronic myeloid leukemia (CML) and myeloproliferative diseases (MPD). Earlier studies show that excessive amounts of reactive oxygen species (ROS) are produced in Kras-mutated myeloid malignancies. Myeloid cells, including Kras-mutated leukemic cells, express the ROS-generating enzyme NOX2. Relatively little is known about the impact of ROS formation, in particular NOX2-derived ROS formation, on leukemogenesis. Mice where oncogenic Kras was induced in hematopoietic cells of LSL-KrasG12D and Mx1-Cre double transgenic mice with ensuing myeloproliferation were treated with a histamine H2-receptor selective NOX2 inhibitor, Nα -methyl histamine (NMH) to assess whether NOX2 is a feasible therapeutic target in Kras-driven leukemia. Spleens of diseased Kras mice were infiltrated with mature CD11b+Gr1+ myeloid cells that expressed NOX2 and produced ROS. The NOX2-dependent formation of ROS in CD11b+Gr1+ cells was inhibited by NMH. In vivo administration of NMH delayed the development of myeloproliferative disease and significantly prolonged survival of Kras mice (p=0.003). In contrast, treatment with NMH did not alter the survival of mice when Kras expression was induced in hematopoietic cells of NOX2-deficient mice that did not produce ROS (Nox2-/-, LSL-KrasG12D and Mx1-Cre triple transgenic mice). In Kras-mutated Nox+/+ mice, but not in Kras-mutated Nox-/- mice, the in vivo administration of NMH entailed diminished ROS levels and reduced oxidative stress as reflected by reduced DCFDA and anti-8 Hydroxyguanosine staining. We propose that NOX2-derived ROS in Kras-mutated hematopoetic cells mediate genomic instability that may contribute to the progression of leukemia. Strategies to target NOX2 should be further evaluated in Ras-mutated hematopoietic cancer. <!–EndFragment–> Citation Format: Ebru Aydin, Alexander Hallner, Hanna Grauers Wiktorin, Anna Staffas, Kristoffer Hellstrand, Anna Martner. NOX2 inhibition reduces oxidative stress and prolongs survival of mice with Kras induced myeloproliferative disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 441.

Entamoeba histolytica Trophozoites Induce a Rapid Non-classical NETosis Mechanism Independent of NOX2-Derived Reactive Oxygen Species and PAD4 Activity.

Neutrophil extracellular traps (NETs) are DNA fibers decorated with histones and antimicrobial proteins from cytoplasmic granules released into the extracellular space in a process denominated NETosis. The molecular pathways involved in NETosis have not been completely understood. Classical NETosis mechanisms involve the neutrophil elastase (NE) translocation to nucleus due to the generation of reactive oxygen species (ROS) by NADPH oxidase (NOX2) or the peptidyl arginine deiminase 4 (PAD4) activation in response to an increase in extracellular calcium influx; both mechanisms result in DNA decondensation. Previously, we reported that trophozoites and lipopeptidophosphoglycan from Entamoeba histolytica trigger NET release in human neutrophils. Here, we demonstrated in a quantitative manner that NETs were rapidly form upon treatment with amoebic trophozoites and involved both nuclear and mitochondrial DNA (mtDNA). NETs formation depended on amoeba viability as heat-inactivated or paraformaldehyde-fixed amoebas were not able to induce NETs. Interestingly, ROS were not detected in neutrophils during their interaction with amoebas, which could explain why NOX2 inhibition using apocynin did not affect this NETosis. Surprisingly, whereas calcium chelation reduced NET release induced by amoebas, PAD4 inhibition by GSK484 failed to block DNA extrusion but, as expected, abolished NETosis induced by the calcium ionophore A23187. Additionally, NE translocation to the nucleus and serine-protease activity were necessary for NET release caused by amoeba. These data support the idea that E. histolytica trophozoites trigger NETosis by a rapid non-classical mechanism and that different mechanisms of NETs release exist depending on the stimuli used.

NADPH oxidase 2 deletion enhances neurogenesis following traumatic brain injury

The NADPH oxidase (NOX) enzyme family is a major source of reactive oxygen species (ROS) and contributor to the secondary pathology underlying traumatic brain injury (TBI). However, little is known about how NOX-derived ROS influences the proliferation and cell-fate determination of neural stem/progenitor cells (NSCs/NPCs) following TBI. In the current study, we found that deletion of NOX2 (NOX2-KO) significantly decreases the population of radial glia-like NSCs and neuroblasts but maintains the population of non-radial Sox2 expressing stem cells under physiological (non-injury) conditions. Surprisingly, the brains of NOX2-KO mice demonstrated a robust increase in the number of neuroblasts during the first week after TBI, as compared to the wild-type group. This increase may result from an enhanced proliferation of NPCs in a lower ROS environment after brain injury, as further examination revealed a significant increase of dividing neuroblasts in both NOX2-KO and NOX inhibitor-treated mouse brain during the first week following TBI. Finally, 5-Bromo-2′-deoxyuridine (BrdU) lineage tracing demonstrated a significantly increased number of newborn neurons were present in the perilesional cortex of NOX2-KO mice at 5 weeks post TBI, indicating that deletion of NOX2 promotes long-term neurogenesis in the injured brain following TBI. Altogether, these findings suggest that targeting NOX through genetic deletion or inhibition enhances post-injury neurogenesis, which may be beneficial for recovery following TBI.

NOX2-derived ROS in myeloid cell differentiation: Implications in cancer

The NOX2 enzyme is highly expressed in normal myeloid cells, as well as in subpopulations of malignant myeloid cells, where it contributes to the generation of reactive oxygen species (ROS). We have utilized mice and leukemic cells genetically depleted of NOX2 and the NOX2-specific inhibitor histamine dihydrochloride (HDC) to further elucidate the role of NOX2-derived ROS in hematopoietic cancer. HDC was found to promote the maturation of human DCs from monocytes and to enhance T cell priming. In addition, treatment of mice with HDC reduced the growth of murine EL-4 lymphomas in parallel with an increment of tumor-infiltrating DCs in NOX2-sufficient mice but not in Nox2-/- mice. HDC was also found to facilitated the maturation and inhibit the proliferation of NOX2-expressing human acute myeloid leukemia (AML) cells. These effects were absent in NOX2-/- AML cells. In microarray analysis, HDC was found to regulate the expression of genes involved in cell differentiation and cell cycle progression in NOX2+ but not in NOX2-/- AML cells. In a xenograft mouse model, systemic treatment with HDC reduced the expansion of engrafted monocytic AML cells in bone marrow but did not exert anti-leukemic activity against engrafted NOX2-/- AML cells.

Gene expression and prognosis of NOX family members in gastric cancer.

IntroductionNicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOX) are frequently deregulated in several human malignancies, including gastric cancer (GC). NOX-derived reactive oxygen species have been reported to contribute to gastric carcinogenesis and cancer progression. However, the expression and prognostic role of individual NOX in GC patients remain elusive.Methods and materialsWe investigated genetic alteration and mRNA expression of NOX family in GC patients via the cBioPortal, Human Protein Atlas, and Oncomine databases. Furthermore, we evaluated prognostic value of distinct NOX in GC patients through “The Kaplan–Meier plotter” database.ResultsOur analysis demonstrated that mRNA deregulation of NOX genes was common alteration in GC patients. Compared with normal tissues, NOX1/2/4 mRNA expression levels in GC tissues were higher, while NOX5 and DUOX1/2 expression levels were lower. Importantly, our results indicated that high mRNA expression of NOX2 was associated with better overall survival whereas NOX4 and DUOX1 were correlated with worse overall survival in all GC patients, particularly in intestinal-type GC patients. In addition, our data also shed light on the diverse roles of individual NOX members in GC patients with different clinicopathological features, including human epidermal growth factor receptor 2 status, clinical stages, pathological grades, and different choices of treatments of GC patients.ConclusionThese findings suggest that individual NOX family genes, especially NOX2/4, and DUOX1, are potential prognostic markers in GC and implicate that the use of NOX inhibitor targeting NOX4 and DUOX1 may be an effective strategy for GC therapy.

Fibronectin type III domain containing 5 attenuates NLRP3 inflammasome activation and phenotypic transformation of adventitial fibroblasts in spontaneously hypertensive rats.

Phenotypic transformation of adventitial fibroblasts is important in the pathogenesis of hypertension. This study was designed to determine whether fibronectin type III domain containing 5 (FNDC5) alleviates the phenotypic transformation of adventitial fibroblasts in hypertension and the underlying mechanisms. Experiments were carried out in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) and primary aortic adventitial fibroblasts. FNDC5 was downregulated and NLRP3 inflammasome was activated in aortic adventitia of SHR. FNDC5 overexpression attenuated adventitial fibroblasts phenotypic transformation, excessive synthesis and secretion of matrix components, NLRP3 inflammasome activation and inflammation in adventitial fibroblasts from SHR. Moreover, FNDC5 overexpression reduced NADPH oxidase 2 (NOX2) expression and reactive oxygen species (ROS) production in adventitial fibroblasts from SHR. Similarly, exogenous FNDC5 inhibited adventitial fibroblasts phenotypic transformation, expression of matrix components, NLRP3 inflammasome activation and NOX2 expression in adventitial fibroblasts from SHR. FNDC5 overexpression in rats attenuated phenotypic transformation, inflammation and reactive oxygen species (ROS) production in the aortic adventitia of SHR. Furthermore, FNDC5 overexpression reduced blood pressure and alleviated vascular remodeling in SHR. FNDC5 reduces NOX2-derived ROS production, NLRP3 inflammasome activation and phenotypic transformation in adventitial fibroblasts of SHR. FNDC5 plays a beneficial role in attenuating vascular inflammation, vascular remodeling and hypertension in SHR.

Andrographolide Antagonizes TNF-α-Induced IL-8 via Inhibition of NADPH Oxidase/ROS/NF-κB and Src/MAPKs/AP-1 Axis in Human Colorectal Cancer HCT116 Cells.

Andrographis paniculata Nees is used as a functional food in Japan, Korea, India, and China. Andrographolide, a naturally occurring phytochemical identified in Andrographis paniculata, has been discovered to present anti-inflammatory and anticancer activities. Highly expressed interleukin (IL-8) has been detected in colorectal cancer and is implicated in angiogenesis. However, the effect and molecular mechanisms of IL-8 expression by andrographolide remain obscure in human colorectal cancer cells. The present study was aimed to investigate the effects of andrographolide on TNF-α-induced IL-8 expression and its underlying mechanisms. We found that andrographolide concentration-dependently inhibited TNF-α-induced IL-8 mRNA (2.23 ± 0.15 fold at 20 μM) and protein expression (4.78 ± 0.31 fold at 20 μM) and reduced the IL-8 transcriptional activity (2.59 ± 0.25 fold at 20 μM). TNF-α stimulated the membrane translocation of p47phox to activate reactive oxygen species (ROS)-producing NADPH oxidase (NOX). Furthermore, TNF-α induced Src and MAPKs (Erk1/2, p38 MAPK) phosphorylation, as well as NF-κB and AP-1 binding activities. We found that NF-κB and AP-1 were the critical transcription factors for TNF-α-induced IL-8 expression. Specific inhibitors and mutagenesis studies indicated that Src, Erk1/2, and p38 MAPK are related to TNF-α-induced IL-8. NOX-derived ROS and Src/MAPKs (Erk1/2 and p38 MAPK) functioned as upstream activators of NF-κB and AP-1, respectively. Taken together, andrographolide antagonizes TNF-α-induced IL-8 via inhibition of NADPH oxidase/ROS/NF-κB and Src/MAPKs/AP-1 signaling pathways in HCT116 colorectal cancer cells and then suppresses angiogenesis in the tumor microenvironment.

The β2 Integrin Mac-1 Induces Protective LC3-Associated Phagocytosis of Listeria monocytogenes

The intracellular pathogen Listeria monocytogenes (L.m.) is targeted by the autophagic machinery, but the molecular mechanisms involved and consequences for anti-listerial immunity remain enigmatic. Here, we demonstrate that L.m. infection of macrophages invivo exclusively evokes LC3-associated phagocytosis (LAP), but not canonical autophagy, and that targeting of L.m. by LAP is required for anti-listerial immunity. The pathway leading to LAP induction in response to L.m. infection emanates from the β2 integrin Mac-1 (CR3, integrin αMβ2), a receptor recognizing diverse microbial ligands. Interaction of L.m. with Mac-1 induces acid sphingomyelinase-mediated changes in membrane lipid composition that facilitate assembly and activation of the phagocyte NAPDH oxidase Nox2. Nox2-derived reactive oxygen species then trigger LC3 recruitment to L.m.-containing phagosomes by LAP. By promoting fusion of L.m.-containing phagosomes with lysosomes, LAP increases exposure of L.m. to bactericidal acid hydrolases, thereby enhancing anti-listerial activity of macrophages and immunity of mice.

Glucose-6-phosphate dehydrogenase inhibition attenuates acute lung injury through reduction in NADPH oxidase-derived reactive oxygen species.

Acute lung injury (ALI) is a heterogeneous disease with the hallmarks of alveolar capillary membrane injury, increased pulmonary oedema and pulmonary inflammation. The most common direct aetiological factor for ALI is usually parenchymal lung infection or haemorrhage. Reactive oxygen species (ROS) generated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX2) are thought to play an important role in the pathophysiology of ALI. Glucose-6-phosphate dehydrogenase (G6PD) plays an important role both in production of ROS as well as their removal through the supply of NADPH. However, how G6PD modulation affects NOX2-mediated ROS in the airway epithelial cells (AECs) during acute lung injury has not been explored previously. Therefore, we investigated the effect of G6PD inhibitor, 6-aminonicotinamide on G6PD activity, NOX2 expression, ROS production and enzymatic anti-oxidants in AECs in a mouse model of ALI induced by lipopolysaccharide (LPS). ALI led to increased G6PD activity in the AECs with concomitant elevation of NOX2, ROS, SOD1 and nitrotyrosine. G6PD inhibitor led to reduction of LPS-induced airway inflammation, bronchoalveolar lavage fluid protein concentration as well as NOX2-derived ROS and subsequent oxidative stress. Conversely, ALI led to decreased glutathione reductase activity in AECs, which was normalized by G6PD inhibitor. These data show that activation of G6PD is associated with enhancement of oxidative inflammation in during ALI. Therefore, inhibition of G6PD might be a beneficial strategy during ALI to limit oxidative damage and ameliorate airway inflammation.

Crosstalk between Rac1-mediated actin regulation and ROS production.

The small RhoGTPase Rac1 is implicated in a variety of events related to actin cytoskeleton rearrangement. Remarkably, another event that is completely different from those related to actin regulation has the same relevance; the Rac1-mediated production of reactive oxygen species (ROS) through NADPH oxidases (NOX). Each outcome involves different Rac1 downstream effectors; on one hand, events related to the actin cytoskeleton require Rac1 to bind to WAVEs proteins and PAKs that ultimately promote actin branching and turnover, on the other, NOX-derived ROS production demands active Rac1 to be bound to a cytosolic activator of NOX. How Rac1-mediated signaling ends up promoting actin-related events, NOX-derived ROS, or both is poorly understood. Rac1 regulators, including scaffold proteins, are known to exert tight control over its functions. Hence, evidence of Rac1 regulatory events leading to both actin remodeling and NOX-mediated ROS generation are discussed. Moreover, cellular functions linked to physiological and pathological conditions that exhibit crosstalk between Rac1 outcomes are analyzed, while plausible roles in neuronal functions (and dysfunctions) are highlighted. Together, discussed evidence shed light on cellular mechanisms which requires Rac1 to direct either actin- and/or ROS-related events, helping to understand crucial roles of Rac1 dual functionality.