bims-noxint Biomed News
on NADPH oxidases in tumorigenesis
Issue of 2019‒05‒12
eight papers selected by
Laia Caja Puigsubira
Uppsala University

  1. Redox Biol. 2019 Apr 16. pii: S2213-2317(19)30006-0. [Epub ahead of print] 101191
    Patel B, Zheleznova NN, Ray SC, Sun J, Cowley AW, O'Connor PM.
      Hv1 is a voltage-gated proton channel highly expressed in immune cells where, it acts to maintain NAD(P)H oxidase activity during the respiratory burst. We have recently reported that Hv1 is expressed in cells of the medullary thick ascending limb (mTAL) of the kidney and is critical to augment reactive oxygen species (ROS) production by this segment. While Hv1 is associated with NOX2 mediated ROS production in immune cells, the source of the Hv1 dependent ROS in mTAL remains unknown. In the current study, the rate of ROS formation was quantified in freshly isolated mTAL using dihydroethidium and ethidium fluorescence. Hv1 dependent ROS production was stimulated by increasing bath osmolality and ammonium chloride (NH4Cl) loading. Loss of either p67phox or NOX4 did not abolish the formation of ROS in mTAL. Hv1 was localized to mitochondria within mTAL, and the mitochondrial superoxide scavenger mitoTEMPOL reduced ROS formation. Rotenone significantly increased ROS formation and decreased mitochondrial membrane potential in mTAL from wild-type rats, while treatment with this inhibitor decreased ROS formation and increased mitochondrial membrane potential in mTAL from Hv1-/- mutant rats. These data indicate that NADPH oxidase is not the primary source of Hv1 dependent ROS production in mTAL. Rather Hv1 localizes to the mitochondria in mTAL and modulates the formation of ROS by complex I. These data provide a potential explanation for the effects of Hv1 on ROS production in cells independent of its contribution to maintenance of cell membrane potential and intracellular pH.
  2. J Med Invest. 2019 ;66(1.2): 93-98
    Kondo S, Matsuura S, Ariunbold J, Kinoshita Y, Urushihara M, Suga K, Ozaki N, Nagai T, Fujioka K, Kagami S.
      Ureteric bud branching and nephrogenesis are performed through large-scale proliferation and apoptosis events during renal development. Reactive oxygen species (ROS), produced by NADPH oxidase, may contribute to cell behaviors, including proliferation and apoptosis. We investigated the role of NADPH oxidase expression and ROS production in developing kidneys. Immunohistochemistry revealed that NADPH oxidase componentswere expressed on epithelial cells in ureteric bud branches, as well as on immature glomerular cells and epithelial cells in nephrogenic zones. ROS production, detected by dihydroethidium assay, was strongly observed in ureteric bud branches and nephrogenic zones, corresponding with NADPH oxidase localization. Organ culture of E14 kidneys revealed that the inhibition of NADPH oxidase significantly reduced the number of ureteric bud branches and tips, consistent with reduced ROS production. This was associated with reduced expression of phosphorylated ERK1/2 and increased expression of cleaved caspase-3. Organ culture of E18 kidneys showed that the inhibition of NADPH oxidase reduced nephrogenic zone size, accompanied by reduced ROS production, fewer proliferating cell nuclear antigen-positive cells, lower p-ERK1/2 expression, and increased expression of cleaved caspase-3. These results demonstrate that ROS produced by NADPH oxidase might play an important role in ureteric bud branching and nephrogenesis by regulating proliferation and apoptosis. J.Med. Invest. 66 :93-98, February, 2019.
    Keywords:  NADPH oxidase; developing kidney; oxidative stress
  3. Platelets. 2019 May 10. 1-6
    Naime ACA, Bonfitto PHL, Solon C, Lopes-Pires ME, Anhê GF, Antunes E, Marcondes S.
      Increased reactive oxygen species (ROS) production leads to tissue damage observed in sepsis and lipopolysaccharide (LPS)-exposed animals. LPS stimulates cytokines releasing, including tumor necrosis factor alpha (TNF-α), that is important to ROS production. Platelets, considered inflammatory cells, generate ROS when exposed to LPS in vivo, but not when they are incubated in vitro with this compound. Therefore, we investigated the role of TNF-α on the increased intraplatelet ROS levels after LPS treatment. Mice were injected with LPS (1 mg/kg) or TNF-α (10 ng/kg), and blood was collected to prepare the washed platelets. Animals were treated with infliximab (anti-TNF-α antibody), R-7050 (non-selective TNF-α receptor antagonist) or apocynin (NADPH oxidase inhibitor). At 48 h after LPS or TNF-α injection, the ROS levels in ADP (25 µM)-activated platelets were evaluated by flow cytometry. Our data showed that injection of mice with LPS increased by 4-fold the ROS production (p < 0.05), which was significantly reduced by the treatments with infliximab, R-7050 or apocynin. Injection of mice with TNF-α markedly elevated the ROS formation in platelets (p < 0.05) that was reduced by infliximab, R-7050 or apocynin treatments. In separate experiments, platelets from saline-injected mice were incubated with TNF-α (30 to 3000 pg/mL) in absence or presence of infliximab, R-7050, apocynin or GKT137831 (NOX1/NOX4 inhibitor) before ROS measurements. TNF-α in vitro markedly increased the ROS levels, an effect significantly reduced by all treatments. Therefore, platelets are involved in the oxidative stress induced by LPS through TNF-α action, and NADPH oxidase takes part in this effect.
    Keywords:  Apocynin; NADPH oxidase; R-7050; infliximab; sepsis
  4. Mol Med Rep. 2019 Apr 22.
    He J, Huang T, Zhao L.
      3,3'‑Diindolylmethane (DIM) is a naturally derived indole compound found in the Brassica family of vegetables. DIM has several beneficial effects, including anti‑cancer, anti‑inflammatory and anti‑angiogenic functions. However, the effects of DIM on acute kidney injury (AKI) stimulated by lipopolysaccharide (LPS) are poorly studied. In this present study, male BALB/c mouse models of AKI were established using intraperitoneal injections of 10 mg/kg LPS. DIM (40 mg/kg) was administered intraperitoneally 24 and 2 h before LPS exposure. The results indicated that DIM significantly mitigated histopathological changes in the kidneys and improved the levels of blood urea nitrogen and serum creatinine. DIM also suppressed the LPS‑induced production of reactive oxygen species and cell apoptosis. Furthermore, DIM treatment significantly decreased the expression of NADPH oxidase 2 (NOX2) and NOX4 in LPS‑treated mice. Therefore, DIM may exert its renoprotective actions by inhibiting NOX‑mediated oxidative stress and the apoptosis of renal tubular epithelial cells.
  5. Curr Clin Pharmacol. 2019 May 02.
    Najafi M, Shirazi A, Motevaseli E, Geraily G, Amini P, Tooli LF, Shabeeb D.
      BACKGROUND: Exposure to ionizing radiation may lead to chronic upregulation of inflammatory mediators and pro-oxidant enzymes, which give rise to continuous production of reactive oxygen species (ROS). NADPH oxidases are among the most important ROS producing enzymes. Their upregulation is associated with DNA damage and genomic instability. In present study, we wanted to determine the expressions of NADPH oxidases; NOX2 and NOX4, in rat's lung following whole body or pelvis irradiation. In addition, we evaluated the protective effect of melatonin on the expressions of NOX2 and NOX4, as well as oxidative DNA injury.MATERIALS AND METHODS: 35 male rats were divided into 7 groups, G1: control; G2: melatonin (100 mg/kg) treatment; G3: whole body irradiation (2 Gy); G4: melatonin plus whole body irradiation; G5: local irradiation to pelvis area; G6: melatonin treatment plus 2 Gy gamma rays to pelvis area; G7: scatter group. All rats were sacrificed after 24 h. Afterwards, the expressions of TGFβR1, Smad2, NF-κB, NOX2 and NOX4 were detected using real-time PCR. Also, the level of 8-OHdG was detected by ELISA, and NOX2 and NOX4 protein levels detected by western blot.
    RESULTS: Whole body irradiation led to upregulation of all genes, while local pelvis irradiation caused upregulation of TGFβR1, NF-κB, NOX2 and NOX4, as well as protein levels of NOX2 and NOX4. Treatment with melatonin reduced the expressions of these genes and also alleviated oxidative injury in both targeted and non-targeted lung tissues. results also showed no significant reduction for NOX2 and NOX4 in bystander tissues following melatonin treatment.
    CONCLUSION: It is possible that upregulation of NOX2 and NOX4 are involved in radiation-induced targeted and non-targeted lung injury. Melatonin may reduce oxidative stress following upregulation of these enzymes in direct irradiated lung tissues but not for bystander.
    Keywords:  Lung; Melatonin; NOX2; NOX4; Radiation
  6. Nitric Oxide. 2019 May 04. pii: S1089-8603(18)30381-1. [Epub ahead of print]
    Sui Y, Tian R, Lu N.
      Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and oxidative stress is usually considered as an important factor to the pathogenesis of various diseases. Inorganic nitrite, previously viewed as a harmful substance in our diet or inert metabolites of endogenous NO, is recently identified as an important biological NO reservoir in vasculature and tissues. Stimulation of a nitrite-NO pathway shows organ-protective effects on oxidative stress and inflammation, but the mechanisms or target are not clear. In this study, the hypothesis that inorganic nitrite attenuated lipopolysaccharide (LPS)-induced oxidative stress in mice and in macrophage cells by modulating NADPH oxidase activity and NO bioavailability were investigated. We showed that nitrite treatment, in sharp contrast with the worsening effect of NO synthases inhibition, significantly attenuated aortic oxidative stress, endothelial dysfunction and mortality in LPS-induced shock in mice. Mechanistically, protective effects of nitrite were abolished by NO scavenger and xanthine oxidase inhibitor, and inhibition of NADPH oxidase with apocynin attenuated LPS-induced oxidative stress similar to that of nitrite. In the presence of nitrite, no further effect of apocynin was observed, suggesting NADPH oxidase as a possible target. In LPS-activated macrophage cells, nitrite reduced NADPH oxidase activity and oxidative stress and these effects of nitrite were also abolished by NO scavenger and xanthine oxidase inhibitor, where xanthine oxidase-mediated reduction of nitrite attenuated NADPH oxidase activity in activated macrophages via a NO-dependent mechanism. In conclusion, these novel findings position NADPH oxidase in the inflammatory vasculature as a prime target for the antioxidant effects of inorganic nitrite, and open a new direction to modulate the inflammatory response.
    Keywords:  Inflammatory vasculature; NADPH oxidase; Nitrate; Nitric oxide; Nitrite; Oxidative stress
  7. Biomed Pharmacother. 2019 May 07. pii: S0753-3322(19)30549-9. [Epub ahead of print]115 108955
    Yang Q, Zhang P, Liu T, Zhang X, Pan X, Cen Y, Liu Y, Zhang H, Chen X.
      Radiation-induced pulmonary fibrosis (RIPF) is a severe complication in patients treated with thoracic irradiation. Until now, there are no effective therapeutic drugs for RIPF. In the present study, we attempted to evaluate the effect of Magnesium isoglycyrrhizinate (MgIG) on RIPF, and to further explore the underlying mechanisms. We found that MgIG treatment markedly improved radiation-induced lung pathological changes, reduced collagen deposition, and decreased the transforming growth factor beta1 (TGF-β1) elevation induced by irradiation. In addition, MgIG treatment significantly relieved oxidative damage of pulmonary fibrosis in mice characterized by increased antioxidant factors expression and reduced oxidative factors expression. And, MgIG treatment also significantly reduced the production of intracellular reactive oxygen species (ROS) in vitro. Interestingly, administration of MgIG achieved lower expression levels of Nox4, and phosphorylation of p38MAPK and Akt in vivo and in vitro. Furthermore, treatment with MgIG notably reduced the expression levels of myofibroblast markers, Nox4, and phosphorylation of p38MAPK and Akt both in vivo and in vitro. More importantly, the inhibitory effects of MgIG on fibroblast differentiation were enhanced when the p38MAPK/Akt/Nox4 pathway was inhibited using their respective antagonists or Nox4 siRNA in vitro. Taken together, these findings suggested that MgIG could attenuate RIPF partly by inhibiting fibroblast differentiation, which was closely related to modulation of the p38MAPK/Akt/Nox4 pathway.
    Keywords:  Fibroblast differentiation; Magnesium isoglycyrrhizinate; Pulmonary fibrosis; Radiation
  8. J Hepatol. 2019 May 06. pii: S0168-8278(19)30273-9. [Epub ahead of print]
    Nishio T, Hu R, Koyama Y, Liang S, Rosenthal SB, Yamamoto G, Karin D, Baglieri J, Ma HY, Xu J, Liu X, Dhar D, Iwaisako K, Taura K, Brenner DA, Kisseleva T.
      BACKGROUND AND AIMS: Chronic liver injury often results in activation of hepatic myofibroblasts and development of liver fibrosis. Hepatic myofibroblasts may originate from three major sources; Hepatic Stellate Cells (HSCs), Portal Fibroblasts (PFs), or fibrocytes. Their contribution to liver fibrosis varies dependent on the etiology of liver injury. Here we assessed the composition of hepatic myofibroblasts in multidrug resistance gene 2 knockout (Mdr2-/-) mice, a genetic model that resembles primary sclerosing cholangitis in patients.METHODS: Mdr2-/- mice expressing a collagen-GFP reporter were analyzed at different ages. Hepatic nonparenchymal cells isolated from collagen-GFP Mdr2-/- mice were sorted based on collagen-GFP and vitamin A. A nicotinamide adenine dinucleotide phosphate oxidase (NOX) 1/4 inhibitor was administrated to Mdr2-/- mice during ages 12- to 16-weeks-old to assess the therapeutic approach targeting oxidative stress in cholestatic injury.
    RESULTS: Thy1+ activated PFs (aPFs) accounted for 26%, 51%, and 54% of collagen-GFP+ myofibroblasts in Mdr2-/- mice at 4 weeks, 8 weeks, and 16 weeks of age, respectively. The remaining collagen-GFP+ myofibroblasts were composed of activated HSCs (aHSCs), suggesting that PFs and HSCs are both activated in Mdr2-/- mice. BM-derived fibrocytes minimally contributed to liver fibrosis in Mdr2-/- mice. Development of cholestatic liver fibrosis in Mdr2-/- mice was associated with early recruitment of Gr1+ myeloid cells and upregulation of pro-inflammatory cytokines (4 weeks). Administration of a NOX inhibitor to 12-week-old Mdr2-/- mice suppressed activation of myofibroblasts and attenuated development of cholestatic fibrosis.
    CONCLUSIONS: aPFs and aHSCs contribute to cholestatic fibrosis in Mdr2-/- mice, and serve as targets for anti-fibrotic therapy.
    LAY SUMMARY: Activated Portal Fibroblasts and Hepatic Stellate Cells, but not fibrocytes, contributed to the production of the fibrous scar in livers of Mdr2-/- mice, and these cells can serve as targets for anti-fibrotic therapy in cholestatic injury. Therapeutic inhibition of the enzyme nicotinamide adenine dinucleotide phosphate oxidase (NOX) in Mdr2-/- mice reversed cholestatic fibrosis, suggesting that targeting of NOXs can provide a novel strategy for treatment of cholestatic fibrosis.
    Keywords:  activated Hepatic Stellate Cells; activated Portal Fibroblasts; cholestatic fibrosis