bims-noxint Biomed News
on NADPH oxidases in tumorigenesis
Issue of 2019‒12‒29
seven papers selected by
Laia Caja Puigsubira
Uppsala University

  1. Biomol Ther (Seoul). 2020 Jan 01. 28(1): 25-33
    Lee SR, An EJ, Kim J, Bae YS.
      Several recent studies have reported that reactive oxygen species (ROS), superoxide anion and hydrogen peroxide (H2O2), play important roles in various cellular signaling networks. NADPH oxidase (Nox) isozymes have been shown to mediate receptormediated ROS generation for physiological signaling processes involved in cell growth, differentiation, apoptosis, and fibrosis. Detectable intracellular levels of ROS can be induced by the electron leakage from mitochondrial respiratory chain as well as by activation of cytochrome p450, glucose oxidase and xanthine oxidase, leading to oxidative stress. The up-regulation and the hyper-activation of NADPH oxidases (Nox) also likely contribute to oxidative stress in pathophysiologic stages. Elevation of the renal ROS level through hyperglycemia-mediated Nox activation results in the oxidative stress which induces a damage to kidney tissues, causing to diabetic nephropathy (DN). Nox inhibitors are currently being developed as the therapeutics of DN. In this review, we summarize Nox-mediated ROS generation and development of Nox inhibitors for therapeutics of DN treatment.
    Keywords:  Diabetic nephropathy; Kidney; NADPH oxidase; Nox inhibitor; Oxidative stress; Signal transduction
  2. Oxid Med Cell Longev. 2019 ;2019 2051235
    Castaldo M, Zollo C, Esposito G, Ammendola R, Cattaneo F.
      Several enzymes are capable of producing reactive oxygen species (ROS), but only NADPH oxidases (NOX) generate ROS as their primary and sole function. In the central nervous system, NOX2 is the major source of ROS, which play important roles in signalling and functions. NOX2 activation requires p47phox phosphorylation and membrane translocation of cytosolic subunits. We demonstrate that SH-SY5Y cells express p47phox and that the stimulation of Formyl-Peptide Receptor 1 (FPR1) by N-fMLP induces p47phox phosphorylation and NOX-dependent superoxide generation. FPR1 is a member of the G protein-coupled receptor (GPCR) family and is able to transphosphorylate several tyrosine kinase receptors (RTKs). This mechanism requires ROS as signalling intermediates and is necessary to share information within the cell. We show that N-fMLP stimulation induces the phosphorylation of cytosolic Y490, Y751, and Y785 residues of the neurotrophin receptor TrkA. These phosphotyrosines provide docking sites for signalling molecules which, in turn, activate Ras/MAPK, PI3K/Akt, and PLC-γ1/PKC intracellular cascades. N-fMLP-induced ROS generation plays a critical role in FPR1-mediated TrkA transactivation. In fact, the blockade of NOX2 functions prevents Y490, Y751, and Y785 phosphorylation, as well as the triggering of downstream signalling cascades. Moreover, we observed that FPR1 stimulation by N-fMLP also improves proliferation, cellular migration, and neurite outgrowth of SH-SY5Y cells.
  3. Free Radic Biol Med. 2019 Dec 19. pii: S0891-5849(19)31620-X. [Epub ahead of print]147 48-60
    Griess B, Mir S, Datta K, Teoh-Fitzgerald M.
      Tumor associated macrophages (TAM) enhance the aggressiveness of breast cancer via promoting cancer cell growth, metastasis, and suppression of the patient's immune system. These TAMs are polarized in breast cancer with features more closely resembling the pro-tumorigenic and immunosuppressive M2 type rather than the anti-tumor and pro-inflammatory M1 type. The goal of our study was to examine primary human monocyte-derived M1 and M2 macrophages for key redox differences and determine sensitivities of these macrophages to the redox-active drug, MnTE-2-PyP5+. This compound reduced levels of M2 markers and inhibited their ability to promote cancer cell growth and suppress T cell activation. The surface levels of the T cell suppressing molecule, PD-L2, were reduced by MnTE-2-PyP5+ in a dose-dependent manner. This study also examined key differences in ROS generation and scavenging between M1 and M2 macrophages. Our results indicate that M2 macrophages have lower levels of reactive oxygen species (ROS) and lower production of extracellular hydrogen peroxide compared to the M1 macrophages. These differences are due in part to reduced expression levels of pro-oxidants, Nox2, Nox5, and the non-enzymatic members of the Nox complex, p22phox and p47phox, as well as higher levels of antioxidant enzymes, Cu/ZnSOD, Gpx1, and catalase. More importantly, we found that despite having lower ROS levels, M2 macrophages require ROS for proper polarization, as addition of hydrogen peroxide increased M2 markers. These TAM-like macrophages are also more sensitive to the ROS modulator and a pan-Nox inhibitor. Both MnTE-2-PyP5+ and DPI inhibited expression levels of M2 marker genes. We have further shown that this inhibition was partly mediated through a decrease in Stat3 activation during IL4-induced M2 polarization. Overall, this study reveals key redox differences between M1 and M2 primary human macrophages and that redox-active drugs can be used to inhibit the pro-tumor and immunosuppressive phenotype of TAM-like M2 macrophages. This study also provides rationale for combining MnTE-2-PyP5+ with immunotherapies.
    Keywords:  Breast cancer; Immunosuppression; ROS; SOD mimetics; Stat3; Tumor associated macrophages
  4. Diabetes. 2019 Dec 27. pii: db190517. [Epub ahead of print]
    Eid SA, El Massry M, Hichor M, Haddad M, Grenier J, Dia B, Barakat R, Boutary S, Chanal J, Aractingi S, Wiesel P, Szyndralewiez C, Azar ST, Boitard C, Zaatari G, Eid AA, Massaad C.
      Diabetes triggers peripheral nerve alterations at a structural and functional level, collectively referred to as Diabetic Peripheral Neuropathy (DPN).This work highlights the role of the oxysterol/LXR signaling pathway and the crosstalk with the reactive oxygen species (ROS) producing enzyme, NADPH oxidase-4 (Nox4) in the pathogenesis of DPN.Herein, we assess behavioral, molecular and physio-pathological changes in cultured Schwann cells as well as in the sciatic nerve of a type 1 diabetic (T1DM) murine model, and skin biopsies from type 2 diabetic (T2DM) patients.T1DM animals exhibit neurophysiological defects and sensorimotor abnormalities paralleled by a defective peripheral myelin genes expression in MPZ and PMP22. These alterations were concomitant with a significant reduction in LXR expression and increase in Nox4 expression and activity in SCs and peripheral nerves, which were further verified in T2DM patients. Moreover, targeted activation of LXR or specific inhibition of Nox4 in vivo and in vitro was shown to attenuate diabetes-induced ROS production, SC and peripheral nerve dysfunction and preserve the homeostatic profiles of MPZ and PMP22.Taken together, our findings are the first to identify novel, key mediators in the pathogenesis of DPN and suggest the targeting of the LXR/Nox4 axis as a promising therapeutic approach.
  5. Cell Mol Neurobiol. 2019 Dec 21.
    Parekh RU, Robidoux J, Sriramula S.
      Neuroinflammation has become an important underlying factor in many cardiovascular disorders, including hypertension. Previously we showed that elevated angiotensin II (Ang II) and angiotensin II type I receptor (AT1R) expression levels can increase neuroinflammation leading to hypertension. We also found that kinin B1 receptor (B1R) expression increased in the hypothalamic paraventricular neurons resulting in neuroinflammation and oxidative stress in neurogenic hypertension. However, whether there are any potential interactions between AT1R and B1R in neuroinflammation is not clear. In the present study, we aimed to determine whether Ang II-mediated effects on inflammation and oxidative stress are mediated by the activation of B1R in mouse neonatal primary hypothalamic neuronal cultures. Gene expression and immunostaining revealed that both B1R and AT1R are expressed on primary hypothalamic neurons. Ang II stimulation significantly increased the expression of B1R, decreased mitochondrial respiration, increased the expression of two NADPH oxidase subunits (Nox2 and Nox4), increased the oxidative potential, upregulated several proinflammatory genes (IL-1β, IL-6, and TNFα), and increased NF-kB p65 DNA binding activity. These changes were prevented by pretreatment with the B1R-specific peptide antagonist, R715. In summary, our study demonstrates a causal relationship between B1R expression after Ang II stimulation, suggesting a possible cross talk between AT1R and B1R in neuroinflammation and oxidative stress.
    Keywords:  AT1R; Angiotensin II; Kinin B1R; Mitochondrial respiration; Neuroinflammation; Oxidative stress
  6. Antioxid Redox Signal. 2019 Dec 27.
    Plaza W, Estay Vizcarra SF, de la Fuente-Ortega E, Gutierrez C, Sanchez G, Hidalgo C, Chávez AE, Haeger P.
      Pre and/or early postnatal ethanol exposure (PAE) impairs synaptic plasticity as well as memory formation, but the mechanisms underlying these effects remain unclear. Both long-term potentiation (LTP) and spatial memory formation in the hippocampus involve the NADPH oxidase type-2 (NOX2) enzyme. Previous studies have reported that NMDA receptor (NMDAR) activation increases NOX2-mediated superoxide generation, resulting in inhibition of NMDAR function, but whether NOX2 impacts NMDAR function in PAE animals leading to impaired LTP and memory formation remains unknown. Aim: To evaluate whether the NOX2-NMDAR complex is involved in the long-lasting deleterious effects of PAE on hippocampal LTP and memory formation. Results: Here we provide novel evidence that PAE animals display impaired NMDAR-dependent LTP in the CA1 and NMDAR-mediated LTP in the dentate gyrus (DG).Moreover, PAE rats displayed increased NMDAR-mediated transmission in both hippocampal areas. Interestingly, NOX2 pharmacological inhibition restored NMDAR-mediated transmission and LTP in the CA1 but not in the DG. PAE also induced over-expression of NOX2 and CaMKII isoforms but did not modify the content or the redox state of the NR1 subunit of NMDAR in both areas of the hippocampus. In addition, adolescent PAE rats orally fed the antioxidant and free radical scavenger apocynin exhibited significantly improved spatial memory acquisition. Innovation and conclusion: By showing in PAE animals NOX2 overexpression and increased NMDAR-mediated transmission, which might lead to impaired synaptic plasticity and memory formation in a region-specific manner, we provide an important advance to our current understanding of the cellular mechanisms underlying PAE-dependent defective hippocampal function.
  7. Cell Rep. 2019 Dec 24. pii: S2211-1247(19)31577-3. [Epub ahead of print]29(13): 4435-4446.e9
    Bode K, Bujupi F, Link C, Hein T, Zimmermann S, Peiris D, Jaquet V, Lepenies B, Weyd H, Krammer PH.
      Uptake of apoptotic cells (ACs) by dendritic cells (DCs) and induction of a tolerogenic DC phenotype is an important mechanism for establishing peripheral tolerance to self-antigens. The receptors involved and underlying signaling pathways are not fully understood. Here, we identify Dectin-1 as a crucial tolerogenic receptor binding with nanomolar affinity to the core domain of several annexins (annexin A1, A5, and A13) exposed on ACs. Annexins bind to Dectin-1 on a site distinct from the interaction site of pathogen-derived β-glucans. Subsequent tolerogenic signaling induces selective phosphorylation of spleen tyrosine kinase (SYK), causing activation of NADPH oxidase-2 and moderate production of reactive oxygen species. Thus, mice deficient for Dectin-1 develop autoimmune pathologies (autoantibodies and splenomegaly) and generate stronger immune responses (cytotoxic T cells) against ACs. Our data describe an important immunological checkpoint system and provide a link between immunosuppressive signals of ACs and maintenance of peripheral immune tolerance.
    Keywords:  Dectin-1; NOX-2; SYK; annexin (A1, A5, and A13); apoptotic cells; autoimmunity; biased agonism; dendritic cells; peripheral immune tolerance; reactive oxygen species