bims-noxint Biomed News
on NADPH oxidases in tumorigenesis
Issue of 2020‒08‒30
four papers selected by
Laia Caja Puigsubira
Uppsala University

  1. Mediators Inflamm. 2020 ;2020 1078365
    Zeng SY, Yan QJ, Yang L, Mei QH, Lu HQ.
      Oxidative stress, inflammation, and hypertension constitute a self-perpetuating vicious circle to exacerbate hypertension and subsequent hypertensive cardiac hypertrophy. NADPH oxidase (Nox) 1/4 inhibitor GKT137831 alleviates hypertensive cardiac hypertrophy in models of secondary hypertension; however, it remains unclear about its effect on hypertensive cardiac hypertrophy in models of essential hypertension. This study is aimed at determining the beneficial role of GKT137831 in hypertensive cardiac hypertrophy in spontaneously hypertensive rats (SHRs) and its mechanisms of action. Treating with GKT137831 prevented cardiac hypertrophy in SHRs. Likewise, decreasing production of reactive oxygen species (ROS) with GKT137831 reduced epidermal growth factor receptor (EGFR) activity in the left ventricle of SHRs. Additionally, EGFR inhibition also reduced ROS production in the left ventricle and blunted hypertensive cardiac hypertrophy in SHRs. Moreover, inhibition of the ROS-EGFR pathway with Nox1/4 inhibitor GKT137831 or selective EGFR inhibitor AG1478 reduced protein and mRNA levels of proinflammatory cytokines tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and interleukin 1β (IL-1β), as well as the activities of Akt and extracellular signal-regulated kinase (ERK) 1/2 in the left ventricle of SHRs. In summary, GKT137831 prevents hypertensive cardiac hypertrophy in SHRs, Nox-deprived ROS regulated EGFR activation through positive feedback in the hypertrophic myocardium, and inhibition of the ROS-EGFR pathway mediates the protective role of GKT137831 in hypertensive cardiac hypertrophy via repressing cardiac inflammation and activation of Akt and ERK1/2. This research will provide additional details for GKT137831 to prevent hypertensive cardiac hypertrophy.
  2. FASEB J. 2020 Aug 26.
    Vara D, Tarafdar A, Celikag M, Patinha D, Gulacsy CE, Hounslea E, Warren Z, Ferreira B, Koeners MP, Caggiano L, Pula G.
      Growing evidence supports a central role of NADPH oxidases (NOXs) in the regulation of platelets, which are circulating cells involved in both hemostasis and thrombosis. Here, the use of Nox1-/- and Nox1+/+ mice as experimental models of human responses demonstrated a critical role of NOX1 in collagen-dependent platelet activation and pathological arterial thrombosis, as tested in vivo by carotid occlusion assays. In contrast, NOX1 does not affect platelet responses to thrombin and normal hemostasis, as assayed in tail bleeding experiments. Therefore, as NOX1 inhibitors are likely to have antiplatelet effects without associated bleeding risks, the NOX1-selective inhibitor 2-acetylphenothiazine (2APT) and a series of its derivatives generated to increase inhibitory potency and drug bioavailability were tested. Among the 2APT derivatives, 1-(10H-phenothiazin-2-yl)vinyl tert-butyl carbonate (2APT-D6) was selected for its high potency. Both 2APT and 2APT-D6 inhibited collagen-dependent platelet aggregation, adhesion, thrombus formation, superoxide anion generation, and surface activation marker expression, while responses to thrombin or adhesion to fibrinogen were not affected. In vivo administration of 2APT or 2APT-D6 led to the inhibition of mouse platelet aggregation, oxygen radical output, and thrombus formation, and carotid occlusion, while tail hemostasis was unaffected. Differently to in vitro experiments, 2APT-D6 and 2APT displayed similar potency in vivo. In summary, NOX1 inhibition with 2APT or its derivative 2APT-D6 is a viable strategy to control collagen-induced platelet activation and reduce thrombosis without deleterious effects on hemostasis. These compounds should, therefore, be considered for the development of novel antiplatelet drugs to fight cardiovascular diseases in humans.
    Keywords:  NADPH oxidase; free radical; hemostasis; oxidative stress; platelet; redox; thrombosis
  3. Exp Ther Med. 2020 Oct;20(4): 3709-3719
    Wei YJ, Xu HJ, Chen JJ, Yang X, Xiong J, Wang J, Cheng F.
      Oxidative stress and apoptosis serve an important role in the development of pressure overload-induced cardiac remodelling. Carnosic acid (CA) has been found to exert antioxidant and anti-apoptotic effects. The present study investigated the underlying mechanism of CA protection and whether this effect was exerted against pressure overload-induced cardiac remodelling. Aortic banding (AB) surgery was performed to induce cardiac remodelling. Mice were randomly divided into four groups (n=15/group): i) Sham + vehicle; ii) sham + CA; iii) AB + vehicle; and iv) AB + CA. After 2 days of AB, 50 mg kg CA was administered orally for 12 days. Echocardiography, histological analysis and molecular biochemistry techniques were performed to evaluate the roles of CA. CA treatment decreased cardiac hypertrophy, fibrosis, oxidative stress and apoptosis in mice challenged with pressure overload. CA also decreased the cross-sectional area of cardiomyocytes and the mRNA and protein expression levels of hypertrophic markers. Furthermore, CA treatment decreased collagen deposition, α-smooth muscle actin expression and the mRNA and protein expression of various fibrotic markers. Additionally, CA reversed the AB-mediated increase in NAPDH oxidase (NOX) 2, NOX4 and 4-hydroxynonenal levels. The number of apoptotic cells was decreased following CA treatment following under conditions of pressure overload. CA also suppressed the activation of AKT and glycogen synthase kinase 3 β (GSK3β) in mice challenged with AB. The present results suggested that CA could inhibit pressure overload-induced cardiac hypertrophy and fibrosis by suppressing the AKT/GSK3β/NOX4 signalling pathway. Therefore, CA may be a promising therapy for cardiac remodelling.
    Keywords:  AKT; cardiac fibrosis; cardiac hypertrophy; carnosic acid; oxidative stress
  4. Eur J Pharmacol. 2020 Aug 20. pii: S0014-2999(20)30506-9. [Epub ahead of print] 173414
    Cai X, Yang C, Shao L, Zhu H, Wang Y, Huang X, Wang S, Hong L.
      Oxidative stress is the key factor of myocardial ischemia-reperfusion injury (MIRI). Anthocyanins are considered to be effective anti-oxidants. In this study, we observed the anti-MIRI effect of petunidin, one member of anthocyanins, and further explored its mechanism. In present study, anoxia/reoxygenation (A/R) models were replicated on Langendorff-perfused heart and neonatal rat primary cardiomyocytes by A/R treatment. The hemodynamic parameters of isolated hearts were monitored. The levels of oxidative stress and apoptosis in isolated heart and neonatal rat primary cardiomyocytes were evaluated. The expression levels of NADPH oxidase 2 (NOX 2), NOX 4, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X (Bax) and cytochrome c were detected by Western Blot. The results showed that petunidin could significantly improve isolated heart function, reduce oxidative stress, inhibit cardiomyocyte apoptosis, up-regulate Bcl-2 protein expression, down-regulate NOX4 and Bax expression, and reduce the level of cytoplasmic cytochrome c after A/R. However, it has no significant effect on NOX 2 protein expression, suggesting that NOX 4 may be the molecular target of petunidin. In vitro, petunidin had shown a consistent effect with that in isolated hearts. It also showed a significant inhibitory effect on reactive oxygen species (ROS) generation. However, the protective effects of petunidin on A/R injury were attenuated by over-expression of NOX 4 in neonatal rat primary cardiomyocytes. These data suggested that the protective effects of petunidin on MIRI may be achieved through targeting NOX 4, thus inhibiting the production of ROS, reducing oxidative stress, and regulating the Bcl-2 pathway to prevent cardiomyocytes apoptosis.
    Keywords:  Apoptosis; Cardioprotection; NOX 4; Oxidative stress; Petunidin