bims-noxint Biomed News
on NADPH oxidases in tumorigenesis
Issue of 2019‒09‒08
seven papers selected by
Laia Caja Puigsubira
Uppsala University

  1. Cell Rep. 2019 Sep 03. pii: S2211-1247(19)31023-X. [Epub ahead of print]28(10): 2501-2508.e4
    Yang WH, Ding CC, Sun T, Rupprecht G, Lin CC, Hsu D, Chi JT.
      Despite recent advances, the poor outcomes in renal cell carcinoma (RCC) suggest novel therapeutics are needed. Ferroptosis is a form of regulated cell death, which may have therapeutic potential toward RCC; however, much remains unknown about the determinants of ferroptosis susceptibility. We found that ferroptosis susceptibility is highly influenced by cell density and confluency. Because cell density regulates the Hippo-YAP/TAZ pathway, we investigated the roles of the Hippo pathway effectors in ferroptosis. TAZ is abundantly expressed in RCC and undergoes density-dependent nuclear or cytosolic translocation. TAZ removal confers ferroptosis resistance, whereas overexpression of TAZS89A sensitizes cells to ferroptosis. Furthermore, TAZ regulates the expression of Epithelial Membrane Protein 1 (EMP1), which, in turn, induces the expression of nicotinamide adenine dinucleotide phosphate (NADPH) Oxidase 4 (NOX4), a renal-enriched reactive oxygen species (ROS)-generating enzyme essential for ferroptosis. These findings reveal that cell density-regulated ferroptosis is mediated by TAZ through the regulation of EMP1-NOX4, suggesting its therapeutic potential for RCC and other TAZ-activated tumors.
    Keywords:  EMP1; Epithelial Membrane Protein 1; Hippo pathway; NADPH Oxidase 4; NOX4; TAZ; WW Domain Containing Transcription Regulator 1; cell density; erastin; ferroptosis; renal cell carcinoma
  2. Biosci Biotechnol Biochem. 2019 Sep 06. 1-9
    Zhang Q, Zhao S, Zheng W, Fu H, Wu T, Hu F.
      Plumbagin (PLB), an alkaloid obtained from the roots of the plants of Plumbago genus, is an inhibitor of NADPH oxidase 4 (NOX4). This study aimed to investigate the beneficial effect of PLB against oxygen-glucose deprivation/reoxygenation (OGDR)-induced neuroinjury in human SH-SY5Y neuronal cultures. Our results showed that OGD/R stimulated NOX4 protein expression and reactive oxygen species (ROS) production in SH-SY5Y cells, whereas increased 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA) production, resulting in the activation of the NLRP3 inflammasome. And PLB pretreatment reduced the ROS production by regulating the expression of NOX4 and downregulated NF-κB signaling which was induced by OGDR. Furthermore, PLB inhibited OGDR induced NLRP3 inflammasome activation but not PARP1. Overall, PLB improved OGDR induced neuroinjury by inhibiting NOX4-derived ROS-activated NLRP3 inflammasome.
    Keywords:  NADPH oxidase 4(NOX4); NLRP3; Plumbagin; SH-SY5Y; reactive oxygen species (ROS)
  3. Int J Mol Sci. 2019 Sep 05. pii: E4357. [Epub ahead of print]20(18):
    Chen YY, Wu TT, Ho CY, Yeh TC, Sun GC, Kung YH, Wong TY, Tseng CJ, Cheng PW.
      PURPOSE: Cataracts in patients with diabetes mellitus (DM) are a major cause of blindness in developed and developing countries. This study aims to examine whether the generation of reactive oxygen species (ROS) via the increased expression of glucose transporters (GLUTs) and the receptor for advanced glycation end products (RAGE) influences the cataract development in DM.METHODS: Lens epithelial cells (LECs) were isolated during cataract surgery from patients without DM or with DM, but without diabetic retinopathy. In a rat model, fructose (10% fructose, 8 or 12 weeks) with or without dapagliflozin (1.2 mg/day, 2 weeks) treatment did induce DM, as verified by blood pressure and serum parameter measurements. Immunofluorescence stainings and immunoblottings were used to quantify the protein levels. Endogenous O2˙¯ production in the LECs was determined in vivo with dihydroethidium stainings.
    RESULTS: We investigated that GLUT levels in LECs differed significantly, thus leading to the direct enhancement of RAGE-associated superoxide generation in DM patients with cataracts. Superoxide production was significantly higher in LECs from rats with fructose-induced type 2 DM, whereas treatment with the sodium-glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin prevented this effect in fructose-fed rats. Protein expression levels of the sodium/glucose cotransporter 2 (SGLT2), GLUT1, GLUT5, the nicotinamide adenine dinucleotide phosphate reduced form (NADPH) oxidase subunit p67-phox, NOX2/4 and RAGE were upregulated in fructose-fed animals, whereas dapagliflozin treatment reversed these effects.
    CONCLUSIONS: In rats with fructose-induced DM, dapagliflozin downregulates RAGE-induced NADPH oxidase expression in LECs via the inactivation of GLUTs and a reduction in ROS generation. These novel findings suggest that the SGLT2 inhibitor dapagliflozin may be a candidate for the pharmacological prevention of cataracts in patients with DM.
    Keywords:  NADPH oxidase; cataract; dapagliflozin; glucose transporter; type 2 diabetes mellitus
  4. J Exp Med. 2019 Sep 06. pii: jem.20180371. [Epub ahead of print]
    Ohayon D, De Chiara A, Dang PM, Thieblemont N, Chatfield S, Marzaioli V, Burgener SS, Mocek J, Candalh C, Pintard C, Tacnet-Delorme P, Renault G, Lagoutte I, Favier M, Walker F, Hurtado-Nedelec M, Desplancq D, Weiss E, Benarafa C, Housset D, Marie JC, Frachet P, El-Benna J, Witko-Sarsat V.
      Neutrophils produce high levels of reactive oxygen species (ROS) by NADPH oxidase that are crucial for host defense but can lead to tissue injury when produced in excess. We previously described that proliferating cell nuclear antigen (PCNA), a nuclear scaffolding protein pivotal in DNA synthesis, controls neutrophil survival through its cytosolic association with procaspases. We herein showed that PCNA associated with p47phox, a key subunit of NADPH oxidase, and that this association regulated ROS production. Surface plasmon resonance and crystallography techniques demonstrated that the interdomain-connecting loop of PCNA interacted directly with the phox homology (PX) domain of the p47phox. PCNA inhibition by competing peptides or by T2AA, a small-molecule PCNA inhibitor, decreased NADPH oxidase activation in vitro. Furthermore, T2AA provided a therapeutic benefit in mice during trinitro-benzene-sulfonic acid (TNBS)-induced colitis by decreasing oxidative stress, accelerating mucosal repair, and promoting the resolution of inflammation. Our data suggest that targeting PCNA in inflammatory neutrophils holds promise as a multifaceted antiinflammatory strategy.
  5. Oxid Med Cell Longev. 2019 ;2019 5174957
    Terluk MR, Ebeling MC, Fisher CR, Kapphahn RJ, Yuan C, Kartha RV, Montezuma SR, Ferrington DA.
      Age-related macular degeneration (AMD) involves the loss of retinal pigment epithelium (RPE) and photoreceptors and is one of the leading causes of blindness in the elderly. Oxidative damage to proteins, lipids, and DNA has been associated with RPE dysfunction and AMD. In this study, we evaluated oxidative stress in AMD and the efficacy of antioxidant, N-acetyl-L-cysteine (NAC), in protecting RPE from oxidative damage. To test this idea, primary cultures of RPE from human donors with AMD (n = 32) or without AMD (No AMD, n = 21) were examined for expression of NADPH oxidase (NOX) genes, a source of reactive oxygen species (ROS). Additionally, the cells were pretreated with NAC for 2 hours and then treated with either hydrogen peroxide (H2O2) or tert-butyl hydroperoxide (t-BHP) to induce cellular oxidation. Twenty-four hours after treatment, ROS production, cell survival, the content of glutathione (GSH) and adenosine triphosphate (ATP), and cellular bioenergetics were measured. We found increased expression of p22phox, a NOX regulator, in AMD cells compared to No AMD cells (p = 0.02). In both AMD and No AMD cells, NAC pretreatment reduced t-BHP-induced ROS production and protected from H2O2-induced cell death and ATP depletion. In the absence of oxidation, NAC treatment improved mitochondrial function in both groups (p < 0.01). Conversely, the protective response exhibited by NAC was disease-dependent for some parameters. In the absence of oxidation, NAC significantly reduced ROS production (p < 0.001) and increased GSH content (p = 0.02) only in RPE from AMD donors. Additionally, NAC-mediated protection from H2O2-induced GSH depletion (p = 0.04) and mitochondrial dysfunction (p < 0.05) was more pronounced in AMD cells compared with No AMD cells. These results demonstrate the therapeutic benefit of NAC by mitigating oxidative damage in RPE. Additionally, the favorable outcomes observed for AMD RPE support NAC's relevance and the potential therapeutic value in treating AMD.
  6. Exp Physiol. 2019 Sep 02.
    Wang K, Zhu ZF, Chi RF, Li Q, Yang ZJ, Jie X, Hu XL, Han XB, Wang JP, Li B, Qin FZ, Fan B.
      NEW FINDINGS: What is the central question of this study? We investigate whether NADPH oxidase activation mediates cardiac sympathetic nerve denervation and dysfunction in heart failure. What is the main findings and its importance? Cardiac sympathetic nerve terminal density and function were reduced in heart failure after myocardial infarction in rabbits. NADPH oxidase inhibitor apocynin prevents the reduction in cardiac sympathetic nerve terminal density and function in heart failure. These findings suggest that NADPH oxidase activation mediates cardiac sympathetic nerve terminal abnormalities in heart failure. NADPH oxidase may be a potential therapeutic target for cardiac sympathetic denervation and dysfunction in heart failure.ABSTRACT: Congestive heart failure (CHF) is characterized by cardiac sympathetic nerve terminal abnormalities, as evidenced by the decreases of norepinephrine transporter (NET) density and cardiac catecholaminergic and tyrosine hydroxylase (TH) profiles. These alterations are associated with increased reactive oxygen species (ROS). NADPH oxidase is a major source of ROS in CHF. In this study, we tested the hypothesis that NADPH oxidase activation mediates cardiac sympathetic nerve terminal abnormalities in CHF. CHF was produced by myocardial infarction (MI) in rabbits. Rabbits with MI or sham operation were randomized to orally receive an NADPH oxidase inhibitor apocynin (6 mg k-1 g/day) or placebo for 30 days. MI rabbits exhibited left ventricular (LV) dilation and systolic dysfunction, and the increases in NADPH oxidase activity and 4-hydroxynonenal expression in the remote non-infarcted myocardium, all of which were prevented by the treatment of apocynin. Cardiac catecholaminergic histofluorescence profiles and immunostained TH and PGP9.5 expression were decreased, and the decreases were ameliorated by the apocynin treatment. NET, TH and PGP9.5 protein and mRNA expression were reduced and the reduction was mitigated by the apocynin treatment. The effects of apocynin were confirmed by utilizing the NADPH oxidase inhibitor diphenyleneiodonium in a separate experiment. In conclusion, the NADPH oxidase inhibitor apocynin attenuated increased myocardial oxidative stress and decreased cardiac sympathetic nerve terminals in CHF after MI in rabbits. These findings suggest that the activation of NADPH oxidase mediates cardiac sympathetic nerve terminal abnormalities in CHF, and the inhibition of NADPH oxidase may be beneficial for the treatment of heart failure.
    Keywords:  Cardiac sympathetic nerve terminals; Heart failure; NADPH oxidase inhibitor
  7. Redox Biol. 2019 Aug 22. pii: S2213-2317(19)30383-0. [Epub ahead of print]28 101304
    Kopacz A, Klóska D, Proniewski B, Cysewski D, Personnic N, Piechota-Polańczyk A, Kaczara P, Zakrzewska A, Forman HJ, Dulak J, Józkowicz A, Grochot-Przęczek A.
      Premature senescence, a death escaping pathway for cells experiencing stress, is conducive to aging and cardiovascular diseases. The molecular switch between senescent and apoptotic fate remains, however, poorly recognized. Nrf2 is an important transcription factor orchestrating adaptive response to cellular stress. Here, we show that both human primary endothelial cells (ECs) and murine aortas lacking Nrf2 signaling are senescent but unexpectedly do not encounter damaging oxidative stress. Instead, they exhibit markedly increased S-nitrosation of proteins. A functional role of S-nitrosation is protection of ECs from death by inhibition of NOX4-mediated oxidative damage and redirection of ECs to premature senescence. S-nitrosation and senescence are mediated by Keap1, a direct binding partner of Nrf2, which colocalizes and precipitates with nitric oxide synthase (NOS) and transnitrosating protein GAPDH in ECs devoid of Nrf2. We conclude that the overabundance of this "unrestrained" Keap1 determines the fate of ECs by regulation of S-nitrosation and propose that Keap1/GAPDH/NOS complex may serve as an enzymatic machinery for S-nitrosation in mammalian cells.
    Keywords:  Keap1; NOX4; Nrf2; Oxidative stress; S-nitrosation; S-nitrosylation