bims-noxint Biomed News
on NADPH oxidases in tumorigenesis
Issue of 2019‒11‒10
seven papers selected by
Laia Caja Puigsubira
Uppsala University

  1. Life Sci. 2019 Nov 02. pii: S0024-3205(19)30811-2. [Epub ahead of print] 116884
    Chu FF, Esworthy RS, Shen B, Gao Q, Doroshow JH.
      C57BL6/J (B6) mice lacking Se-dependent GSH peroxidase 1 and 2 (GPx1/2-DKO) develop mild to moderate ileocolitis around weaning. These DKO mice have a disease resembling human very-early-onset inflammatory bowel disease (VEOIBD), which is associated with mutations in NADPH oxidase genes. Drugs including dexamethasone (Dex), Tofacitinib (Tofa; a Janus kinase/JAK inhibitor) and anti-TNF antibody are effective to treat adult, but not pediatric IBD.AIMS: To test the efficacy of hydrophobic Dex and hydrophilic Dex phosphate (Dex phos), Tofa, anti-Tnf Ab, Noxa1ds-TAT and gp91ds-TAT peptides (inhibiting NOX1 and NOX2 assembly respectively), antioxidant MJ33 and ML090, and pifithrin-α (p53 inhibitor) on alleviation of gut inflammation in DKO weanlings.
    MAIN METHODS: All treatments began on 22-day-old GPx1/2-DKO mice. The mouse intestine pathology was compared between the drug- and vehicle-treated groups after six or thirteen days of treatment.
    KEY FINDINGS: Among all drugs tested, Dex, Dex phos and Tofa were the strongest to suppress ileocolitis in the DKO weanlings. Dex, Dex phos and Tofa inhibited crypt apoptosis and increased crypt density. Dex or Dex phos alone also inhibited cell proliferation, exfoliation and crypt abscess in the ileum. Dex, but not Tofa, retarded mouse growth. Both Dex and Tofa inhibited ileum Nox1, Nox4 and Duox2, but not Nox2 gene expression. Noxa1ds-TAT and gp91ds-TAT peptides as well as MJ33 had subtle effect on suppressing pathology, while others had negligible effect.
    SIGNIFICANCE: These findings suggest that NADPH oxidases can be novel drug targets for pediatric IBD therapy, and Tofa may be considered for treating VEOIBD.
    Keywords:  Dexamethasone; Glutathione peroxidase; NADPH oxidase; Tofacitinib; Very-early-onset inflammatory bowel disease
  2. Urolithiasis. 2019 Nov 05.
    Sáenz-Medina J, Muñoz M, Sanchez A, Rodriguez C, Jorge E, Corbacho C, Izquierdo D, Santos M, Donoso E, Virumbrales E, Sanchez A, Ramil E, Coronado MJ, Prieto D, Carballido J.
      Specific relationships among reactive oxygen species, activation pathways, and inflammatory mechanisms involved in kidney injury were assessed in a combined model of obesity and hyperoxaluria. Male Wistar rats were divided into four groups: Control, HFD (high fat diet), OX (0.75% ethylene glycol), and HFD + OX (combined model) Changes in basal O2- levels were evaluated by chemiluminescence in renal interlobar arteries and renal cortex. Furthermore, the effect of different inhibitors on NADPH-stimulated O2- generation was assessed in renal cortex. Oxidative stress sources, and local inflammatory mediators, were also determined, in parallel, by RT-PCR, and correlated with measures of renal function, urinary biochemistry, and renal structure. Rats from the HFD group developed overweight without lipid profile alteration. Tubular deposits of crystals were seen in OX and severely enhanced in HFD + OX groups along with a significantly higher impairment of renal function. Basal oxidative stress was increased in renal cortex of OX rats and in renal arteries of HFD rats, while animals from the combined HFD + OX group exhibited the highest levels of oxidative stress in renal cortex, derived from xanthine oxidase and COX-2. NADPH oxidase-dependent O2- generation was elevated in renal cortex of the OX group and markedly enhanced in the HFD + OX rats, and associated to an up-regulation of Nox1 and a down-regulation of Nox4 expression. High levels of oxidative stress in the kidney, of OX and HFD + OX groups were also associated to an inflammatory response mediated by an elevation of TNFα, COX-2, NFκB1 MCP-1, and OPN. Oxidative stress is a key pathogenic factor in renal disease associated to hyperoxaluria and a common link underlying the exacerbated inflammatory response and kidney injury found under conditions of both obesity and hyperoxaluria. Nox1 pathway must be considered as a potential therapeutic target.
    Keywords:  NADPH oxidase; Obesity; Oxidative stress; Renal injury; Urolithiasis
  3. Redox Biol. 2019 Oct 20. pii: S2213-2317(19)30904-8. [Epub ahead of print]28 101346
    Gattas MV, Jaffe A, Barahona J, Conner GE.
      The NADPH oxidase reaction produces protons. In the case of the NADPH oxidase, NOX2, activity depends on secretion of these protons and is inhibited by blockade of the voltage-gated proton channel (Hv1). Duox1 and Duox2 activities similarly produce intracellular protons but synthesize hydrogen peroxide directly instead of superoxide. Hv1 contributes to acid secretion in some epithelia that express Duox. To test the hypothesis that Duox activity is also sensitive to Hv1 channel blockers, Duox was assayed in the presence of either Zn2+ or 5-chloro-2-guanidinobenzimidazole (ClGBI). Both compounds inhibited Duox activity in normal human bronchial epithelial cells but with an IC50 over 10-fold higher than that reported for Hv1 (IC50 Zn2+ = 0.68 mM; IC50 ClGBI = 0.07-0.14 mM). Homogenized HEK293T cells expressing either Duox1 or Duox2 showed similar IC50 values for ClGBI suggesting these compounds inhibit the enzymes through alternate mechanisms independent of Hv1 proton secretion. Inclusion of superoxide dismutase did not restore Duox hydrogen peroxide synthesis. Addition of nigericin to eliminate any possible transmembrane pH gradients in intracellular membrane-localized Duox did not alter activity in HEK293T homogenates. Extracellular Zn2+ blocked intracellular Ca2+ increases needed for Duox activity. Together the data suggest that Duox enzyme activities in epithelia are inhibited by compounds that block Hv1 but inhibition occurs through Hv1-independent mechanisms and support the idea that Hv1 is not required for Duox activity.
    Keywords:  Bronchial epithelium; Duox; Hv1; Zinc
  4. Molecules. 2019 Nov 05. pii: E3993. [Epub ahead of print]24(21):
    Schiavone S, Tucci P, Trabace L, Morgese MG.
      Administration of subanesthetic doses of ketamine during brain maturation represents a tool to mimic an early insult to the central nervous system (CNS). The cerebellum is a key player in psychosis pathogenesis, to which oxidative stress also contributes. Here, we investigated the impact of early celastrol administration on behavioral dysfunctions in adult mice that had received ketamine (30 mg/kg i.p.) at postnatal days (PNDs) 7, 9, and 11. Cerebellar levels of 8-hydroxydeoxyguanosine (8-OHdG), NADPH oxidase (NOX) 1 and NOX2, as well as of the calcium-binding protein parvalbumin (PV), were also assessed. Furthermore, celastrol effects on ketamine-induced alterations of proinflammatory (TNF-α, IL-6 and IL-1β) and anti-inflammatory (IL-10) cytokines in this brain region were evaluated. Early celastrol administration prevented ketamine-induced discrimination index decrease at adulthood. The same was found for locomotor activity elevations and increased close following and allogrooming, whereas no beneficial effects on sniffing impairment were detected. Ketamine increased 8-OHdG in the cerebellum of adult mice, which was also prevented by early celastrol injection. Cerebellar NOX1 levels were enhanced at adulthood following postnatal ketamine exposure. Celastrol per se induced NOX1 decrease in the cerebellum. This effect was more significant in animals that were early administered with ketamine. NOX2 levels did not change. Ketamine administration did not affect PV amount in the cerebellum. TNF-α levels were enhanced in ketamine-treated animals; however, this was not prevented by early celastrol administration. While no changes were observed for IL-6 and IL-1β levels, ketamine determined a reduction of cerebellar IL-10 expression, which was prevented by early celastrol treatment. Our results suggest that NOX inhibition during brain maturation prevents the development of psychotic-like behavioral dysfunctions, as well as the increased cerebellar oxidative stress and the reduction of IL-10 in the same brain region following ketamine exposure in postnatal life. This opens novel neuroprotective opportunities against early detrimental insults occurring during brain development.
    Keywords:  NADPH oxidases; celastrol; cerebellum; ketamine; oxidative stress; psychosis
  5. Mol Cell Endocrinol. 2019 Oct 30. pii: S0303-7207(19)30337-5. [Epub ahead of print] 110635
    Giusti N, Gillotay P, Trubiroha A, Opitz R, Dumont JE, Costagliola S, De Deken X.
      Thyroid hormone (TH) synthesis requires extracellular hydrogen peroxide generated by the NADPH oxidases, DUOX1 and DUOX2, with maturation factors, DUOXA1 and DUOXA2. In zebrafish, only one duox and one duoxa gene are present. Using a thyroid-specific reporter line, we investigated the role of Duox and Duoxa for TH biosynthesis in zebrafish larvae. Analysis of several zebrafish duox and duoxa mutant models consistently recovered hypothyroid phenotypes with hyperplastic goiter caused by impaired TH synthesis. Mutant larvae developed enlarged thyroids and showed increased expression of the EGFP reporter and thyroid functional markers including wild-type and mutated duox and duoxa transcripts. Treatment of zebrafish larvae with the NADPH oxidase inhibitor VAS2870 phenocopied the thyroid effects observed in duox or duoxa mutants. Additional functional in vitro assays corroborated the pharmacological inhibition of Duox activity by VAS2870. These data support the utility of this new experimental model to characterize endocrine disruptors of the thyroid function.
    Keywords:  Congenital hypothyroidism; DUOX; DUOXA; Thyroid hormones; VAS2870; Zebrafish
  6. Sci Rep. 2019 Nov 07. 9(1): 16242
    Li D, Deconda D, Li A, Habr F, Cao W.
      Acid reflux may contribute to the progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EA). However, it is not clear whether the molecular changes present in BE patients are reversible after proton pump inhibitor (PPI) treatment. In this study we examined whether PPI treatment affects NOX5, microsomal prostaglandin E synthase (mPGES)-1 and inducible nitric oxide synthase (iNOS) expression. We found that NADPH oxidase 5 (NOX5), mPGES-1 and iNOS were significantly increased in BE mucosa. One-month PPI treatment significantly decreased NOX5, mPGES1 and iNOS. In BAR-T cells, NOX5 mRNA and p16 promoter methylation increased after pulsed acid treatment in a time-dependent manner. Four or eight-week-acid induced increase in NOX5 mRNA, NOX5 protein and p16 methylation may be reversible. Twelve-week acid treatment also significantly increased NOX5, mPGES1 and iNOS mRNA expression. However, twelve-week-acid-induced changes only partially restored or did not recover at all after the cells were cultured at pH 7.2 for 8 weeks. We conclude that NOX5, mPGES1 and iNOS may be reversible after PPI treatment. Short-term acid-induced increase in NOX5 expression and p16 methylation might be reversible, whereas long-term acid-induced changes only partially recovered 8 weeks after removal of acid treatment.
  7. Biochemistry. 2019 Nov 08.
    Luo M, Willis WT, Coletta DK, Langlais PR, Mengos A, Ma W, Finlayson J, Wagner GR, Shi CX, Mandarino LJ.
      Von Willebrand A Domain-Containing Protein 8 (VWA8) is a poorly-characterized, mitochondrial matrix-targeted protein with a AAA ATPase domain and ATPase activity that rises in abundance in livers of high fat fed mice. This study was undertaken to use CRISPR/Cas9 to delete VWA8 in cultured mouse hepatocytes and gain insight into its function. Unbiased omics techniques and bioinformatics were used to guide subsequent assays, including assessment of oxidative stress and determination of bioenergetic capacity. Metabolomics analysis showed VWA8 null cells had higher oxidative stress and protein degradation; assays of hydrogen peroxide production revealed higher production of reactive oxygen species (ROS). Proteomics and transcriptomics analyses showed VWA8 null cells had higher expression of mitochondrial proteins (electron transport chain Complex I, ATP synthase), peroxisomal proteins, and lipid transport proteins. The pattern of higher protein abundance in the VWA8 null cells could be explained by higher hepatocyte nuclear factor 4 alpha (HNF4a) expression. Bioenergetic assays showed higher rates of carbohydrate oxidation and mitochondrial and non-mitochondrial lipid oxidation in intact and permeabilized cells. Inhibitor assays localized sites of ROS production to peroxisomes and NOX1/4. Rescue of VWA8 protein restored the wildtype phenotype and treatment with antioxidants lowered HNF4a expression. Thus, loss of VWA8 produces a mitochondrial defect that may be sensed by NOX4, leading to a rise in ROS that results in higher HNF4a. The compensatory HNF4a response results in higher oxidative capacity and even higher ROS production. We hypothesize that VWA8 is a AAA ATPase protein that plays a role in mitochondrial protein quality.