bims-noxint Biomed News
on NADPH oxidases in tumorigenesis
Issue of 2020‒05‒17
fifteen papers selected by
Laia Caja Puigsubira
Uppsala University

  1. Arthritis Res Ther. 2020 May 15. 22(1): 116
    Lee HR, Yoo SJ, Kim J, Yoo IS, Park CK, Kang SW.
      BACKGROUND: Reactive oxygen species (ROS) regulate the migration and invasion of fibroblast-like synoviocytes (FLS), which are key effector cells in rheumatoid arthritis (RA) pathogenesis. Nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) induces ROS generation and, consequently, enhances cell migration. Despite the important interrelationship between RA, FLS, and ROS, the effect of NOX4 on RA pathogenesis remains unclear.METHODS: FLS isolated from RA (n = 5) and osteoarthritis (OA, n = 5) patients were stimulated with recombinant interleukin 17 (IL-17; 10 ng/ml) and tumor necrosis factor alpha (TNF-α; 10 ng/ml) for 1 h. Cell migration, invasion, adhesion molecule expression, vascular endothelial growth factor (VEGF) secretion, and ROS expression were examined. The mRNA and protein levels of NOX4 were analyzed by RT-qPCR and western blotting, respectively. The NOX4 inhibitor GLX351322 and NOX4 siRNA were used to inhibit NOX4 to probe the effect of NOX4 on these cellular processes.
    RESULTS: Migration of RA FLS was increased 2.48-fold after stimulation with IL-17 and TNF-α, while no difference was observed for OA FLS. ROS expression increased in parallel with invasiveness of FLS following cytokine stimulation. When the expression of NOX was examined, NOX4 was significantly increased by 9.73-fold in RA FLS compared to unstimulated FLS. Following NOX4 inhibition, cytokine-induced vascular cell adhesion molecule 1 (VCAM1), VEGF, and migration and invasion capacity of RA FLS were markedly decreased to unstimulated levels.
    CONCLUSION: NOX4 is a key contributor to cytokine-enhanced migration and invasion via modulation of ROS, VCAM1, and VEGF in RA FLS.
    Keywords:  Fibroblast-like synoviocytes; NADPH; NOX4; Osteoarthritis; Reactive oxygen species; Rheumatoid arthritis; VCAM1; VEGF
  2. Redox Biol. 2020 Apr 11. pii: S2213-2317(19)31519-8. [Epub ahead of print]34 101536
    Kračun D, Klop M, Knirsch A, Petry A, Kanchev I, Chalupsky K, Wolf CM, Görlach A.
      Cardiovascular side effects are frequent problems accompanying systemic glucocorticoid therapy, although the underlying mechanisms are not fully resolved. Reactive oxygen species (ROS) have been shown to promote various cardiovascular diseases although the link between glucocorticoid and ROS signaling has been controversial. As the family of NADPH oxidases has been identified as important source of ROS in the cardiovascular system we investigated the role of NADPH oxidases in response to the synthetic glucocorticoid dexamethasone in the cardiovascular system in vitro and in vivo in mice lacking functional NADPH oxidases due to a mutation in the gene coding for the essential NADPH oxidase subunit p22phox. We show that dexamethasone induced NADPH oxidase-dependent ROS generation, leading to vascular proliferation and angiogenesis due to activation of the transcription factor hypoxia-inducible factor-1 (HIF1). Chronic treatment of mice with low doses of dexamethasone resulted in the development of systemic hypertension, cardiac hypertrophy and left ventricular dysfunction, as well as in pulmonary hypertension and pulmonary vascular remodeling. In contrast, mice deficient in p22phox-dependent NADPH oxidases were protected against these cardiovascular side effects. Mechanistically, dexamethasone failed to upregulate HIF1α levels in these mice, while vascular HIF1α deficiency prevented pulmonary vascular remodeling. Thus, p22phox-dependent NADPH oxidases and activation of the HIF pathway are critical elements in dexamethasone-induced cardiovascular pathologies and might provide interesting targets to limit cardiovascular side effects in patients on chronic glucocorticoid therapy.
    Keywords:  Glucocorticoid; HIF1; Hypertension; NADPH oxidase; Pulmonary vascular remodeling; ROS; p22phox
  3. Can J Cardiol. 2020 May;pii: S0828-282X(20)30186-0. [Epub ahead of print]36(5): 659-670
    Touyz RM, Rios FJ, Alves-Lopes R, Neves KB, Camargo LL, Montezano AC.
      The etiology of hypertension involves complex interactions among genetic, environmental, and pathophysiologic factors that influence many regulatory systems. Hypertension is characteristically associated with vascular dysfunction, cardiovascular remodelling, renal dysfunction, and stimulation of the sympathetic nervous system. Emerging evidence indicates that the immune system is also important and that activated immune cells migrate and accumulate in tissues promoting inflammation, fibrosis, and target-organ damage. Common to these processes is oxidative stress, defined as an imbalance between oxidants and antioxidants in favour of the oxidants that leads to a disruption of oxidation-reduction (redox) signalling and control and molecular damage. Physiologically, reactive oxygen species (ROS) act as signalling molecules and influence cell function through highly regulated redox-sensitive signal transduction. In hypertension, oxidative stress promotes posttranslational modification (oxidation and phosphorylation) of proteins and aberrant signalling with consequent cell and tissue damage. Many enzymatic systems generate ROS, but NADPH oxidases (Nox) are the major sources in cells of the heart, vessels, kidneys, and immune system. Expression and activity of Nox are increased in hypertension and are the major systems responsible for oxidative stress in cardiovascular disease. Here we provide a unifying concept where oxidative stress is a common mediator underlying pathophysiologic processes in hypertension. We focus on some novel concepts whereby ROS influence vascular function, aldosterone/mineralocorticoid actions, and immunoinflammation, all important processes contributing to the development of hypertension.
  4. Int Immunopharmacol. 2020 May 08. pii: S1567-5769(20)30532-4. [Epub ahead of print]84 106527
    Gao Q, Qin H, Zhu L, Li D, Hao X.
      The present work aimed to investigate the anti-rheumatism effect and the mechanism of celastrol in collagen-induced arthritis (CIA) rats. The CIA model was established in male Wistar rats by intradermal injection of bovine collagen-II in complete Freund's adjuvant (CFA) at the base of tail. The rats received oral administration of celastrol for 28 days. A variety of indicators, including paw swelling and arthritis scores, were measured for anti-rheumatism effect. Celastrol treatment attenuated paw swelling and arthritis scores in CIA rats. Celastrol improved the spleen and thymus indexes in CIA rats. The increased levels of inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and interferon (IFN)-γ, were abolished by celastrol treatment. In addition, the weakened superoxide dismutase (SOD) activity, the increased levels of malondialdehyde (MDA), and superoxide anions, and enhanced NADPH oxidase (Nox) activity were all reversed by celastrol treatment. Nox4 overexpression reversed the attenuating effects of celastrol on paw swelling and arthritis scores in CIA rats. The celastrol-induced improvement in spleen and thymus indexes in CIA rats was inhibited by Nox4 overexpression. Nox4 overexpression reversed the abolishing effects of celastrol on the increases of TNF-α, IL-1β, IL-6, and IFN-γ levels in the serum of CIA rats. These results demonstrated that celastrol improved rheumatism in arthritis via inhibiting oxidative stress.
    Keywords:  Collagen-induced arthritis; Inflammatory cytokines; Oxidative stress; Rat; Rheumatism
  5. Sleep Breath. 2020 May 12.
    Ekin S, Yildiz H, Alp HH.
      PURPOSE: Obstructive sleep apnoea (OSA) involves recurrent obstructive apnoeas and hypopnoeas which cause cyclic hypoxia, reoxygenation and formation of reactive oxygen species (ROS). We aimed to investigate a member of the nicotinamide adenine dinucleotide phosphate oxidase (NOX) family of enzymes, specifically (NOX4), not previously studied in humans, as well as 8-OHdG/106dG, MDA and IMA, which are known to be associated with oxidative stress. We also evaluated these parameters in predicting the presence and severity of OSA.METHODS: All 120 subjects (90 with OSA, 30 healthy controls) underwent polysomnography and had blood serum samples taken at the same time of day. Subjects were grouped by presence and severity of OSA, and serum markers were compared among groups.
    RESULTS: Age and body mass index were not significantly different among groups. In the OSA group, the levels of NOX4, IMA, MDA and 8-OHdG/106dG were significantly higher than in the healthy control group. NOX4 and other parameters were positively correlated with the severity of OSA. For all parameters, the highest levels were detected in patients with severe OSA.
    CONCLUSIONS: The repeated hypoxia of OSA is associated with increases in the serum levels of inflammatory mediators such as MDA, IMA and 8-OHdG/106dG and the ROS NOX4. In this study, NOX4 and other markers were associated with the presence and severity of OSA.
    Keywords:  NOX4; OSA; Oxidative DNA damage; Oxidative stress
  6. Autophagy. 2020 May 13. 1-15
    Keller CW, Kotur MB, Mundt S, Dokalis N, Ligeon LA, Shah AM, Prinz M, Becher B, Münz C, Lünemann JD.
      Whereas central nervous system (CNS) homeostasis is highly dependent on tissue surveillance by immune cells, dysregulated entry of leukocytes during autoimmune neuroinflammation causes severe immunopathology and neurological deficits. To invade the CNS parenchyma, encephalitogenic T helper (TH) cells must encounter their cognate antigen(s) presented by local major histocompatibility complex (MHC) class II-expressing antigen-presenting cells (APCs). The precise mechanisms by which CNS-associated APCs facilitate autoimmune T cell reactivation remain largely unknown. We previously showed that mice with conditional deletion of the gene encoding the essential autophagy protein ATG5 in dendritic cells (DCs) are resistant to EAE development. Here, we report that the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2, also known as CYBB/NOX2, in conventional DCs (cDCs) regulates endocytosed MOG (myelin oligodendrocyte protein) antigen processing and supports MOG-antigen presentation to CD4+ T cells through LC3-associated phagocytosis (LAP). Genetic ablation of Cybb in cDCs is sufficient to restrain encephalitogenic TH cell recruitment into the CNS and to ameliorate clinical disease development upon the adoptive transfer of MOG-specific CD4+ T cells. These data indicate that CYBB-regulated MOG-antigen processing and LAP in cDCs licenses encephalitogenic TH cells to initiate and sustain autoimmune neuroinflammation.ABBREVIATIONS: Ag: antigen; APC: antigen-presenting cell; AT: adoptive transfer; ATG/Atg: autophagy-related; BAMs: border-associated macrophages; BMDC: bone marrow-derived DC; CD: cluster of differentiation; CNS: central nervous system; CSF2/GM-CSF: colony stimulating factor 2 (granulocyte-macrophage); CYBB/NOX2/gp91phox: cytochrome b-245, beta polypeptide; DC: dendritic cell; EAE: experimental autoimmune encephalomyelitis; fl: floxed; FOXP3: forkhead box P3; GFP: green fluorescent protein; H2-Ab: histocompatibility 2, class II antigen A, beta 1; IFN: interferon; IL: interleukin; ITGAX/CD11c: integrin subunit alpha X; LAP: LC3-associated phagocytosis; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MFI: median fluorescence intensity; MG: microglia; MHCII: major histocompatibility complex class II; MOG: myelin oligodendrocyte glycoprotein; MS: multiple sclerosis; NADPH: nicotinamide adenine dinucleotide phosphate; ODC: oligodendroglial cell; OVA: ovalbumin; pDC: plasmacytoid DC; Ptd-L-Ser: phosphatidylserine; PTPRC: protein tyrosine phosphatase, receptor type, C; ROS: reactive oxygen species; SLE: systemic lupus erythematosus; TH cells: T helper cells; TLR: toll-like receptor; ZBTB46: zinc finger and BTB domain containing 46.
    Keywords:  Antigen presentation; CYBB/NOX2; LC3-associated phagocytosis; autophagy; dendritic cells; experimental autoimmune encephalomyelitis; multiple sclerosis
  7. Int J Mol Sci. 2020 May 12. pii: E3420. [Epub ahead of print]21(10):
    Li S, Ung TT, Nguyen TT, Sah DK, Park SY, Jung YD.
      Matrix metalloproteinase-9 (MMP-9) plays a crucial role in cell invasion and cancer metastasis. In this study, we showed that cholic acid (CA), a major primary bile acid, can induce MMP-9 expression in colon cancer HT29 and SW620 cells. CA increased reactive oxygen species (ROS) production and also activated phosphorylation of ERK1/2, JNK, and p38 MAPK. Specific inhibitors and mutagenesis studies showed that ERK1/2 and JNK functioned as upstream signals in the activation of AP-1, and p38 MAPK functioned as an upstream signal in the activation of NF-κB. N-acetyl-L-cysteine (NAC, an ROS scavenger) and diphenyleneiodonium chloride (DPI, an NADPH oxidase inhibitor) inhibited CA-induced activation of ERK1/2, JNK, and p38 MAPK, indicating that ROS production by NADPH oxidase could be the furthest upstream signal in MMP-9 expression. Colon cancer cells pretreated with CA showed remarkably enhanced invasiveness. Such enhancement was partially abrogated by MMP-9-neutralizing antibodies. These results demonstrate that CA could induce MMP-9 expression via ROS-dependent ERK1/2, JNK-activated AP-1, and p38-MAPK-activated NF-κB signaling pathways, which in turn stimulate cell invasion in human colon cancer cells.
    Keywords:  AP-1; MAPK; NF-κB; cell invasion; cholic acid; colon cancer cells; matrix metalloproteinase-9; reactive oxygen species
  8. Int J Mol Sci. 2020 May 12. pii: E3405. [Epub ahead of print]21(10):
    Daiber A, Steven S, Vujacic-Mirski K, Kalinovic S, Oelze M, Di Lisa F, Münzel T.
      Oxidative stress plays a key role for the development of cardiovascular, metabolic, and neurodegenerative disease. This concept has been proven by using the approach of genetic deletion of reactive oxygen and nitrogen species (RONS) producing, pro-oxidant enzymes as well as by the overexpression of RONS detoxifying, antioxidant enzymes leading to an amelioration of the severity of diseases. Vice versa, the development and progression of cardiovascular diseases is aggravated by overexpression of RONS producing enzymes as well as deletion of RONS detoxifying enzymes. We have previously identified cross talk mechanisms between different sources of RONS, which can amplify the oxidative stress-mediated damage. Here, the pathways and potential mechanisms leading to this cross talk are analyzed in detail and highlighted by selected examples from the current literature and own data including hypoxia, angiotensin II (AT-II)-induced hypertension, nitrate tolerance, aging, and others. The general concept of redox-based activation of RONS sources via "kindling radicals" and enzyme-specific "redox switches" as well as the interaction with redox-sensitive inflammatory pathways are discussed. Here, we present evidence for the existence of such cross talk mechanisms in the setting of diabetes and critically assess their contribution to the severity of diabetic complications.
    Keywords:  NADPH oxidase; eNOS uncoupling; endothelial dysfunction; kindling radicals; low-grade inflammation; mitochondria; oxidative stress; redox cross talk
  9. Int Immunopharmacol. 2020 May 05. pii: S1567-5769(20)30495-1. [Epub ahead of print]84 106555
    Al-Harbi NO, Nadeem A, Ahmad SF, Al-Ayadhi LY, Al-Harbi MM, As Sobeai HM, Ibrahim KE, Bakheet SA.
      Autism spectrum disorder (ASD) is a childhood disorder with neurodevelopmental dysfunction which manifests as impairment in social behavior and communication skills. B cells play an important role in immune dysfunction where toll-like receptor 4 (TLR4) may contribute through oxidative inflammatory process. TLR4 related signaling and oxidative stress have been reported in the periphery of ASD subjects, however it has not been evaluated in peripheral B cells of ASD subjects and compared with typically developing control (TDC) children. This study evaluated TLR4 expression and related signaling [Bruton's tyrosine kinase (BTK), spleen tyrosine kinase (SYK), NF-kB, NADPH oxidase (NOX2), nitrotyrosine, superoxide dismutase (SOD)] in ASD and TDC subjects. Current investigation in B cells shows that ASD subjects have increased TLR4 expression and oxidative stress as exhibited by upregulated NOX2 and nitrotyrosine expression as compared to TDC subjects. B cell relevant pathways, BTK/SYK/NF-kB were also upregulated in B cells of ASD group. Treatment with TLR4 agonist, LPS led to upregulation of NOX2 and nitrotyrosine in B cells of ASD whereas it had no significant effect on TDC subjects. Treatment with NF-kB inhibitor caused inhibition of LPS-induced upregulation of NOX2 and nitrotyrosine in B cells of ASD. Therefore, current investigation proposes the notion that TLR4 expression is elevated in B cells which is associated with increased NF-kB signaling and oxidant stress in ASD subjects. In short, peripheral B cells could contribute to systemic oxidative inflammation and contribute to the immune dysfunction in ASD.
    Keywords:  Autism; B cells; NADPH oxidase; Nuclear factor kappa B; Oxidants; Toll-like receptor 4
  10. Am J Physiol Cell Physiol. 2020 May 13.
    Maqbool A, Watt N, Haywood N, Viswambharan H, Skromna A, Makava N, Visnagri A, Shawer HM, Bridge K, Muminov SK, Griffin K, Beech DJ, Wheatcroft SB, Porter KE, Simmons KJ, Sukumar P, Shah AM, Cubbon RM, Kearney MT, Yuldasheva NY.
      Insulin resistance leads to excessive endothelial cell (EC) superoxide generation and accelerated atherosclerosis. The principal source of superoxide from the insulin-resistant endothelium is the Nox2 isoform of NADPH oxidase. Here we examine the therapeutic potential of Nox2 inhibition on: superoxide generation in saphenous vein EC (SVEC) from patients with advanced atherosclerosis and type 2 diabetes; and on vascular function, vascular damage and lipid deposition in Apolipoprotein E deficient (ApoE-/-) mice with EC specific insulin resistance (ESMIRO). To examine the effect of genetic inhibition of Nox2, ESMIRO mice deficient in ApoE-/- and Nox2 (ESMIRO/ApoE-/-/Nox2-/y) were generated and compared to ESMIRO/ApoE-/-/Nox2+/y littermates. To examine the effect of pharmacological inhibition of Nox2 we administered gp91dstat or scrambled peptide to ESMIRO/ApoE-/- mice. SVEC from diabetic patients had increased expression of Nox2 protein with concomitant increase in superoxide generation which could be reduced by the Nox2 inhibitor gp91dstat. After 12 weeks western diet, ESMIRO/ApoE-/-/Nox2-/y mice had reduced EC superoxide generation and greater aortic relaxation to acetylcholine. ESMIRO/ApoE-/-/Nox2-/y mice developed more lipid deposition in the thoraco-abdominal aorta with multiple foci of elastin fragmentation at the level of the aortic sinus and greater expression of intercellular adhesion molecule-1 (ICAM-1). Gp91dstat reduced EC superoxide and lipid deposition in the thoraco-abdominal aorta of ESMIRO/ApoE-/- mice without causing elastin fragmentation or increased ICAM-1 expression. These results demonstrate that insulin resistance is characterized by increased Nox2-derived vascular superoxide. Complete deletion of Nox2 in mice with EC insulin resistance exacerbates, whereas partial pharmacological Nox2 inhibition protects against, insulin resistance-induced vascular damage.
    Keywords:  Nox2; atherosclerosis; insulin resistance
  11. J Orthop Sci. 2020 May 10. pii: S0949-2658(20)30120-2. [Epub ahead of print]
    Lin RJ, Huang Z, Wang SL, Chen H, Wei HX, Shen RK, Yang LY, Lin JH.
      BACKGROUND: Osteosarcoma is the most common primary malignant bone tumor, particularly among children and adolescents, and the prognosis of osteosarcoma patients remains poor. The NADPH oxidase 2 (NOX2) has been found over-expressed in several human cancers, and closely associated with poor prognosis. Meanwhile the role of NOX2 in osteosarcoma patients has not been reported. This study aimed to investigate the clinicopathological and prognostic significance of NOX2 in osteosarcoma patients.METHODS: Immunohistochemistry (IHC), western blot (WB) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to detect the expression of NOX2 in 55 primary osteosarcoma specimens and in 20 non-neoplastic bone tissue specimens. The correlations between NOX2 expression and clinicopathological parameters were analysed by using the χ2 test or Fisher's exact test. Disease free survival and overall survival of osteosarcoma patients were assessed by using the Kaplan-Meier method and Cox proportional hazards model.
    RESULTS: NOX2 was over-expressed significantly in osteosarcoma compared with that in non-neoplastic bone tissue, and correlated with progression free survival (P < 0.001) and overall survival (P < 0.001). The over-expression of NOX2 was associated with tumor size (P < 0.001), tumor location (P < 0.001). The Cox analysed shown that the over-expression of NOX2 was predicted to be worse PFS (hazard ratio (HR) = 4.10, P = 0.004) and OS (hazard ratio (HR) = 3.50, P = 0.010) time in osteosarcoma patients.
    CONCLUSIONS: The results of our study suggest that the over-expression of NOX2 is related to adverse clinical outcome, and can be viewed as an independent prognostic marker in osteosarcoma. Further research is required to verify the predictive value of NOX2 in osteosarcoma patients.
  12. Diabetes. 2020 May 14. pii: db200217. [Epub ahead of print]
    Liu L, Fan L, Chan M, Kraakman MJ, Yang J, Fan Y, Aaron N, Wan Q, Carrillo-Sepulveda MA, Tall AR, Tabas I, Accili D, Qiang L.
      Cardiovascular disease (CVD) is the leading cause of death in diabetic patients; however, tight glycemic control fails to lower the risk. The thiazolidinediones (TZDs), a class of PPARγ agonists, are potent insulin sensitizers with anti-atherogenic properties, but their clinical utilization is limited by the side effects. PPARγ deacetylation on two lysine residues (K268 and K293) induces brown remodeling of white adipose tissue and uncouples TZD's adverse effects from insulin sensitization. Here we show that PPARγ deacetylation confers anti-atherogenic properties and retains the insulin-sensitizing effects of TZD while circumventing its detriments. We generated mice homozygous for deacetylation-mimetic PPARγ mutations K268R/K293R (2KR) mice on an LDL-receptor knockout (Ldlr -/- ) background. 2KR:Ldlr -/- mice showed reduced atherosclerotic lesions compared to Ldlr -/- mice, particularly in aortic arches. With rosiglitazone treatment, 2KR:Ldlr -/- mice demonstrated a residual anti-atherogenic response and significant protection against bone loss and fluid retention. The anti-atherosclerotic effect of 2KR was attributed to the protection of endothelium, indicated by the improved endothelium-dependent vasorelaxation and repressed expression of pro-atherogenic factors including inducible NO synthase (iNOS), IL-6, and NADPH oxidase 2 (Nox2). Therefore, manipulating PPARγ acetylation is a promising therapeutic strategy to control CVD risk in diabetes treatment.
  13. Am J Physiol Heart Circ Physiol. 2020 May 15.
    El-Mahdy MA, Abdelghany TM, Hemann C, Ewees MG, Mahgoup EM, Eid MS, Shalaan MT, Alzarie YA, Zweier JL.
      While there is a strong association between cigarette smoking exposure (CSE) and vascular endothelial dysfunction (VED), the underlying mechanisms by which CSE triggers VED remain unclear. Therefore, studies were performed to define these mechanisms using a chronic mouse model of cigarette smoking (CS)-induced cardiovascular disease mirroring that in humans. C57BL/6 male mice were subjected to CSE for up to 48 weeks. CSE impaired acetylcholine (Ach)-induced relaxation of aortic and mesenteric segments and triggered hypertension with mean arterial blood pressure at 32 and 48 weeks of exposure of 122±6 and 135±5 mmHg compared to 99±4 and 102±6 mmHg respectively, in air-exposed mice. CSE led to monocyte activation with superoxide generation in blood exiting the pulmonary circulation. Macrophage infiltration with concomitant increase in NADPH oxidase subunits p22phox and gp91phox was seen in aortas of CS-exposed mice at 16 weeks, with further increase out to 48 weeks. Associated with this, increased superoxide production was detected that decreased with Nox inhibition. Tetrahydrobiopterin was progressively depleted in CS-exposed mice, but not in air-exposed controls, resulting in endothelial nitric oxide synthase (eNOS) uncoupling and secondary superoxide generation. CSE led to a time-dependent decrease in eNOS and Akt expression and phosphorylation. Overall, CSE induces vascular monocyte infiltration with increased NADPH oxidase-mediated ROS generation and depletes the eNOS co-factor tetrahydrobiopterin, uncoupling eNOS, triggering a vicious cycle of oxidative stress with VED and hypertension. Our study provides important insights toward understanding the process by which smoking contributes to the genesis of cardiovascular disease and identifies biomarkers predictive of disease.
    Keywords:  cigarette smoking; endothelial dysfunction; nitric oxide synthase uncoupling; reactive oxygen species; superoxide
  14. Int J Mol Sci. 2020 May 08. pii: E3328. [Epub ahead of print]21(9):
    Liechty C, Hu J, Zhang L, Liechty KW, Xu J.
      A central feature of diabetic wounds is the persistence of chronic inflammation, which is partly due to the prolonged presence of pro-inflammatory (M1) macrophages in diabetic wounds. Persistence of the M1 macrophage phenotype and failure to transition to the regenerative or pro-remodeling (M2) macrophage phenotype plays an indispensable role in diabetic wound impairment; however, the mechanism underlying this relationship remains unclear. Recently, microRNAs have been shown to provide an additional layer of regulation of gene expression. In particular, microRNA-21 (miR-21) is essential for an inflammatory immune response. We hypothesize that miR-21 plays a role in regulating inflammation by promoting M1 macrophage polarization and the production of reactive oxygen species (ROS). To test our hypothesis, we employed an in vivo mouse skin wound model in conjunction with an in vitro mouse model to assess miR-21 expression and macrophage polarization. First, we found that miR-21 exhibits a distinct expression pattern in each phase of healing in diabetic wounds. MiR-21 abundance was higher during early and late phases of wound repair in diabetic wounds, while it was significantly lower in the middle phase of wounding (at days 3 and 7 following wounding). In macrophage cells, M1 polarized macrophages exhibited an upregulation of miR-21, as well as the M1 and pro-inflammatory markers IL-1b, TNFa, iNos, IL-6, and IL-8. Overexpression of miR-21 in macrophage cells resulted in an upregulation of miR-21 and also increased expression of the M1 markers IL-1b, TNFa, iNos, and IL-6. Furthermore, hyperglycemia induced NOX2 expression and ROS production through the HG/miR-21/PI3K/NOX2/ROS signaling cascade. These findings provide evidence that miR-21 is involved in the regulation of inflammation. Dysregulation of miR-21 may explain the abnormal inflammation and persistent M1 macrophage polarization seen in diabetic wounds.
    Keywords:  ROS; diabetic wounds; macrophage polarization; miR-21; microRNA
  15. Brain Res Bull. 2020 May 07. pii: S0361-9230(20)30097-6. [Epub ahead of print]
    Wang W, Yang L, Liu T, Ma Y, Huang S, He M, Wang J, Wen A, Ding Y.
      Sleep deprivation (SD) can induce cognitive and memory impairments. This impairment is in part due to oxidative stress damage in the hippocampus region of the brain. Corilagin (CL), a polyphenol belonging to the tannin family and extracted from Terminalia chebula and Phyllanthus emblica, shows strong antioxidant and neuroprotective effects. NF-E2-related factor (Nrf2)/heme oxygenase-1 (HO-1) and NADPH oxidase (NOX) are critical targets involved in cellular defense mechanisms against oxidative injury. Thus, we hypothesized that CL could be a preventive treatment for SD-induced memory impairments by inhibiting NOX2 and activating Nrf2. The results from behavioral tests showed that administration of CL resulted in significantly better performance compared to the SD mice. CL significantly normalized the elevated MDA level and the reduced activity of GPx and SOD (P <0.05, p<0.01) caused by SD. In hippocampal tissues, CL effectively activated Nrf2/HO-1 signaling and downregulated NOX2 protein expression compared with SD (P <0.05, P <0.01). Meanwhile, in vitro findings showed that knockdown of Nrf2 blocked the protective effect of CL versus Glu-induced toxicity, while the effect of CL was enhanced in NOX2 siRNA-transfected neurons. Overall, these findings provided evidence that CL ameliorates SD-induced memory impairments in mice by inhibiting NOX2 and activating Nrf2.
    Keywords:  Memory impairments; Oxidative stress; Sleep deprivation