bims-noxint Biomed News
on NADPH oxidases in tumorigenesis
Issue of 2019‒11‒03
fifteen papers selected by
Laia Caja Puigsubira
Uppsala University

  1. Antioxid Redox Signal. 2019 Oct 26.
    Kushwaha P, Gupta S, Singh AK, Prajapati KS, Shuaib M, Kumar S.
      Reactive oxygen species (ROS) production occurs primarily in the mitochondria as a byproduct of cellular metabolism. ROS are also produced by NADPH (nicotinamide adenine dinucleotide phosphate) oxidases in response to growth factors and cytokines by normal physiological signaling pathways. NADPH oxidase, a member of NOX family, utilizes molecular oxygen (O2) to generate ROS such as hydrogen peroxide (H2O2) and superoxide (O2•-). Imbalance between ROS production and its elimination is known to be the major cause of various human diseases. NOX family proteins are exclusively involved in ROS production which makes them attractive target(s) for the treatment of ROS-mediated diseases including cancer. Molecules such as Keap1/Nrf2, N-methyl-D-aspartate receptors (NMDRs), NF-κB, KRAS, kallistatin, gene associated with retinoic-interferon-induced mortality-19 and deregulated metabolic pathways are involved in ROS production in association with NADPH oxidase. Therapeutic strategies targeting NADPH oxidases in ROS driven cancers are not very effective due to its complex regulatory circuit. Tumor suppressor miRNAs viz. miR-34a, miR-137, miR-99a, and miR-21a-3p targeting NADPH oxidases are predominantly downregulated in ROS driven cancers. miRNAs also regulate other cellular machineries such as Keap1/Nrf2 pathway and NMDRs involved in ROS production and consequently drug resistance. Here we discuss the structure, function and metabolic role of NADPH oxidase, NOX family protein-protein interaction, their association with other pathways and NADPH oxidase alteration by miRNAs. Moreover, we also discuss and summarize studies on NADPH oxidase-associated with various malignancies and their therapeutic implications. Targeting NADPH oxidases through miRNAs appears to be a promising strategy for the treatment of ROS driven cancer.
  2. Clin Exp Pharmacol Physiol. 2019 Nov 01.
    Rodriguez R, Escobedo B, Lee AY, Thorwald M, Godoy-Lugo JA, Nakano D, Nishiyama A, Parkes DG, Ortiz RM.
      Insulin resistance increases renal oxidant production by up-regulating NADPH oxidase 4 (Nox4) expression contributing to oxidative damage and ultimately albuminuria. Inhibition of the renin-angiotensin system (RAS) and activation of glucagon-like peptide-1 (GLP-1) receptor signaling may reverse this effect. However, whether angiotensin receptor type 1 (AT1) blockade and GLP-1 receptor activation improve oxidative damage and albuminuria through different mechanisms is not known. Using insulin resistant Otsuka Long Evan Tokushima Fatty (OLETF) rats, we tested the hypothesis that simultaneous blockade of AT1 and activation of GLP-1r additively decrease oxidative damage and urinary albumin excretion (Ualb V) in the following groups: (1) untreated, lean LETO (n=7), (2) untreated, obese OLETF (n=9), (3) OLETF + angiotensin receptor blocker (ARB; 10 mg olmesartan /kg/d; n=9), (4) OLETF + GLP-1 mimetic (EXE; 10 ug exenatide/kg/d; n=7), and (5) OLETF + ARB + exenatide (Combo; n=6). Mean kidney Nox4 protein expression and nitrotyrosine (NT) levels were 30% and 46% greater, respectively, in OLETF compared to LETO. Conversely, Nox4 protein expression and NT were reduced to LETO levels in ARB and EXE, and Combo reduced Nox4, NT, and 4-hydroxy-2-nonenal levels by 21%, 27%, and 27%, respectively. At baseline, Ualb V was nearly double in OLETF compared to LETO, and increased to nearly 10-fold greater levels by the end of the study. While ARB (45%) and EXE (55%) individually reduced Ualb V, the combination completely ameliorated the albuminuria. Collectively, these data suggest that AT1 blockade and GLP-1 receptor activation reduce renal oxidative damage similarly during insulin resistance, while targeting both signaling pathways provides added benefit in restoring and/or further ameliorating albuminuria in a model of diet-induced obesity.
    Keywords:  Chronic kidney disease; diabetes; obesity; oxidative stress; renin-angiotensin-system
  3. FASEB J. 2019 Oct 29. fj201900396RR
    Mroueh FM, Noureldein M, Zeidan YH, Boutary S, Irani SAM, Eid S, Haddad M, Barakat R, Harb F, Costantine J, Kanj R, Sauleau EA, Ouhtit A, Azar ST, Eid AH, Eid AA.
      Cancer was recently annexed to diabetic complications. Furthermore, recent studies suggest that cancer can increase the risk of diabetes. Consequently, diabetes and cancer share many risk factors, but the cellular and molecular pathways correlating diabetes and colon and rectal cancer (CRC) remain far from understood. In this study, we assess the effect of hyperglycemia on cancer cell aggressiveness in human colon epithelial adenocarcinoma cells in vitro and in an experimental animal model of CRC. Our results show that Nox (NADPH oxidase enzyme) 4-induced reactive oxygen species (ROS) production is deregulated in both diabetes and CRC. This is paralleled by inactivation of the AMPK and activation of the mammalian target of rapamycin (mTOR) C1 signaling pathways, resulting in 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) accumulation, induction of DNA damage, and exacerbation of cancer cell aggressiveness, thus contributing to the genomic instability and predisposition to increased tumorigenesis in the diabetic milieu. Pharmacologic activation of AMPK, inhibition of mTORC1, or blockade of Nox4 reduce ROS production, restore the homeostatic signaling of 8-oxoguanine DNA glycosylase/8-oxodG, and lessen the progression of CRC malignancy in a diabetic milieu. Taken together, our results identify the AMPK/mTORC1/Nox4 signaling axis as a molecular switch correlating diabetes and CRC. Modulating this pathway may be a strategic target of therapeutic potential aimed at reversing or slowing the progression of CRC in patients with or without diabetes.-Mroueh, F. M., Noureldein, M., Zeidan, Y. H., Boutary, S., Irani, S. A. M., Eid, S., Haddad, M., Barakat, R., Harb, F., Costantine, J., Kanj, R., Sauleau, E.-A., Ouhtit, A., Azar, S. T., Eid, A. H., Eid, A. A. Unmasking the interplay between mTOR and Nox4: novel insights into the mechanism connecting diabetes and cancer.
    Keywords:  DNA damage; NADPH oxidases; colorectal cancer; mTORC1
  4. Inflammopharmacology. 2019 Oct 30.
    Tannich F, Tlili A, Pintard C, Chniguir A, Eto B, Dang PM, Souilem O, El-Benna J.
      Excessive reactive oxygen species (ROS) production can induce tissue injury involved in a variety of neurodegenerative disorders such as neurodegeneration observed in pilocarpine-induced temporal lobe epilepsy. Ketamine, a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist has beneficial effects in pilocarpine-induced temporal lobe epilepsy, when administered within minutes of seizure to avoid the harmful neurological lesions induced by pilocarpine. However, the enzymes involved in ROS productions and the effect of ketamine on this process remain less documented. Here we show that during pilocarpine-induced epilepsy in mice, the expression of the phagocyte NADPH oxidase NOX2 subunits (NOX2/gp91phox, p22phox, and p47phox) and the expression of myeloperoxidase (MPO) were dramatically increased in mice brain treated with pilocarpine. Interestingly, treatment of mice with ketamine before or after pilocarpine administration decreased this process, mainly when injected before pilocarpine. Finally, our results showed that pilocarpine induced p47phox phosphorylation and H2O2 production in mice brain and ketamine was able to inhibit these processes. Our results show that pilocarpine induced NOX2 activation to produce ROS in mice brain and that administration of ketamine before or after the induction of temporal lobe epilepsy by pilocarpine inhibited this activation in mice brain. These results suggest a key role of the phagocyte NADPH oxidase NOX2 and MPO in epilepsy and identify a novel effect of ketamine.
    Keywords:  Epilepsy; Ketamine; Myeloperoxidase; NOX2; Neuro-Inflammation; Neutrophils; ROS; p47phox
  5. Free Radic Biol Med. 2019 Oct 26. pii: S0891-5849(19)31574-6. [Epub ahead of print]
    Negre-Salvayre A, Guerby P, Gayral S, Laffargue M, Salvayre R.
      Atherosclerosis is a multifactorial chronic and inflammatory disease of medium and large arteries, and the major cause of cardiovascular morbidity and mortality worldwide. The pathogenesis of atherosclerosis involves a number of risk factors and complex events including hypercholesterolemia, endothelial dysfunction, increased permeability to low density lipoproteins (LDL) and their sequestration on extracellular matrix in the intima of lesion-prone areas. These events promote LDL modifications, particularly by oxidation, which generates acute and chronic inflammatory responses implicated in atherogenesis and lesion progression. Reactive oxygen species (ROS) (which include both free radical and non-free radical oxygen intermediates), play a key-role at each step of atherogenesis, in endothelial dysfunction, LDL oxidation, and inflammatory events involved in the initiation and development of atherosclerosis lesions. Most advanced knowledge supporting the "oxidative theory of atherosclerosis" i.e. the nature and the cellular sources of ROS and antioxidant defences, as well as the mechanisms involved in the redox balance, is based on the use of genetically engineered animals, i.e. transgenic, genetically modified, or altered for systems producing or neutralizing ROS in the vessels. This review summarizes the results obtained from animals genetically manipulated for various sources of ROS or antioxidant defences in the vascular wall, and their relevance (advance or limitation), for understanding the place and role of ROS in atherosclerosis.
    Keywords:  Atherosclerosis; Genetic animal models; Lipoxygenases; Mitochondria; Mn-dependent superoxide dismutase; Myeloperoxidase; NADPH oxidase; Nitric oxide synthase; Reactive oxygen species
  6. Biochim Biophys Acta Gen Subj. 2019 Oct 29. pii: S0304-4165(19)30249-1. [Epub ahead of print] 129463
    Mohamed R, Cao Y, Afroz R, Xu S, Ta H, Barras M, Zheng W, Little PJ, Kamato D.
      BACKGROUND: Widely used NAPDH oxidase (Nox) inhibitor, apocynin is a prodrug that needs to be converted to its pharmacologically active form by myeloperoxidase. In myeloperoxidase deficient non phagocytic cells such as vascular smooth muscle cells (VSMCs) apocynin stimulates the production of ROS. ROS is generated by the activation of many signalling pathways, thus we have used apocynin as a pharmacological tool to characterise the role of endogenous ROS in activating the transforming growth factor beta receptor (TGFBR1) without the activation of other pathways.METHODS: The in vitro study utilized human VSMCs. Western blotting and quantitative real time PCR were performed to assess signalling pathways and gene expression, respectively. Intracellular ROS levels was measured using fluorescence detection assay.
    RESULTS: Treatment with apocynin of human VSMCs stimulated ROS production and the phosphorylation of TGFBR1 and subsequent activation of TGFBR1 signalling leading to the formation of phosphorylated Smad2 which consequently upregulates the mRNA expression of glycosaminoglycan synthesizing enzyme.
    CONCLUSIONS: These findings outline a specific involvement of ROS production in TGFBR1 activation. Furthermore, because apocynin stimulates Nox and ROS production, apocynin must be used with considerable care in vitro as its actions clearly extend beyond the stimulation of Nox enzymes and it has consequences for cellular signalling.
    GENERAL SIGNIFICANCE: Apocynin can stimulate Nox leading to the production of ROS and the outcome is completely dependent upon the redox properties of the cell.
    Keywords:  Apocynin; NADPH oxidase; Reactive oxygen species; Smad2 carboxy terminal; Smooth muscle cells; Transforming growth factor β type 1 receptor
  7. Biochem Biophys Res Commun. 2019 Oct 25. pii: S0006-291X(19)32000-5. [Epub ahead of print]
    Rousset F, Zhang L, Lardy B, Morel F, Nguyen MVC.
      The NADPH oxidase Nox4 is a multi-pass membrane protein responsible for the generation of reactive oxygen species that are implicated in cellular signaling but may also cause pathological situations when dysregulated. Although topological organization of integral membrane protein dictates its function, only limited experimental data describing Nox4's topology are available. To provide deeper insight on Nox4 structural organization, we developed a novel method to determinate membrane protein topology in their cellular environment, named Topological Determination by Ubiquitin Fusion Assay (ToDUFA). It is based on the proteolytic capacity of the deubiquitinase enzymes to process ubiquitin fusion proteins. This straightforward method, validated on two well-known protein's topologies (IL1RI and Nox2), allowed us to discriminate rapidly the topological orientation of protein's domains facing either the nucleocytosolic or the exterior/luminal compartments. Using this method, we were able for the first time to determine experimentally the topology of Nox4 which consists of 6 transmembrane domains with its N- and C-terminus moieties facing the cytosol. While the first, third and fifth loops of Nox4 protein are extracellular; the second and fourth loops are located in the cytosolic side. This approach can be easily extended to characterize the topology of all others members of the NADPH oxidase family or any multi-pass membrane proteins. Considering the importance of protein topology knowledge in cell biology research and pharmacological development, we believe that this novel method will represent a widely useful technique to easily uncover complex membrane protein's topology.
    Keywords:  Membrane topology; NADH oxidase 4; Ubiquitin
  8. Mol Med Rep. 2019 Oct 29.
    Han H, Dai D, Hu J, Zhu J, Lu L, Tao G, Zhang R.
      Dexmedetomidine (DEX), a highly specific and selective α2 adrenergic receptor agonist, has been demonstrated to possess potential cardioprotective effects. However, the mechanisms underlying this process remain to be fully illuminated. In the present study, a myocardial infarction (MI) animal model was generated by permanently ligating the left anterior descending coronary artery in mice. Cardiac function and collagen content were evaluated by transthoracic echocardiography and picrosirius red staining, respectively. Apoptosis was determined by the relative expression levels of Bax and Bcl‑2 and the myocardial caspase‑3 activity. Additionally, nicotinamide adenine dinucleotide phosphate oxidase (NOX)‑derived oxidative stress was evaluated by the relative expression of Nox2 and Nox4, along with the myocardial contents of malondialdehyde (MDA) and superoxide dismutase (SOD) activity. It was demonstrated that intraperitoneal DEX treatment (20 µg/kg/day) improved the systolic function of the left ventricle, and decreased the fibrotic changes in post‑myocardial infarction mice, which was paralleled by a decrease in the levels of apoptosis. Subsequent experiments indicated that the restoration of redox signaling was achieved by DEX administration, and the over‑activation of NOXs, including Nox2 and Nox4, was markedly inhibited. In conclusion, this present study suggested that DEX was cardioprotective and limited the excess production of NOX‑derived ROS in ischemic heart disease, implying that DEX is a promising novel drug, especially for patients who have suffered MI.
  9. Antioxidants (Basel). 2019 Oct 10. pii: E471. [Epub ahead of print]8(10):
    Kim EK, Jang M, Song MJ, Kim D, Kim Y, Jang HH.
      Cellular reactive oxygen species (ROS) status is stabilized by a balance of ROS generation and elimination called redox homeostasis. ROS is increased by activation of endoplasmic reticulum stress, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family members and adenosine triphosphate (ATP) synthesis of mitochondria. Increased ROS is detoxified by superoxide dismutase, catalase, and peroxiredoxins. ROS has a role as a secondary messenger in signal transduction. Cancer cells induce fluctuations of redox homeostasis by variation of ROS regulated machinery, leading to increased tumorigenesis and chemoresistance. Redox-mediated mechanisms of chemoresistance include endoplasmic reticulum stress-mediated autophagy, increased cell cycle progression, and increased conversion to metastasis or cancer stem-like cells. This review discusses changes of the redox state in tumorigenesis and redox-mediated mechanisms involved in tolerance to chemotherapeutic drugs in cancer.
    Keywords:  5-Fluorouracil; antioxidant proteins; chemoresistance; oxaliplatin; reactive oxygen species
  10. Hypertension. 2019 Oct 28. HYPERTENSIONAHA11913398
    Bruder-Nascimento T, Faulkner JL, Haigh S, Kennard S, Antonova G, Patel VS, Fulton DJR, Chen W, Belin de Chantemèle EJ.
      Leptin is the current treatment for metabolic disorders associated with acquired and congenital generalized lipodystrophy (CGL). Although excess leptin levels have been associated with vascular inflammation and cardiovascular disease in the context of obesity, the effects of chronic leptin treatment on vascular function remain unknown in CGL. Here, we hypothesized that leptin treatment will improve endothelial function via direct vascular mechanisms. We investigated the cardiovascular consequences of leptin deficiency and supplementation in male gBscl2-/- (Berardinelli-Seip 2 gene-deficient) mice-a mouse model of CGL. CGL mice exhibited reduced adipose mass and leptin levels, as well as impaired endothelium-dependent relaxation. Blood vessels from CGL mice had increased NADPH Oxidase 1 (Nox1) expression and reactive oxygen species production, and selective Nox1 inhibition restored endothelial function. Remarkably, chronic and acute leptin supplementation restored endothelial function via a PPARγ-dependent mechanism that decreased Nox1 expression and reactive oxygen species production. Selective ablation of leptin receptors in endothelial cells promoted endothelial dysfunction, which was restored by Nox1 inhibition. Lastly, we confirmed in aortic tissue from older patients undergoing cardiac bypass surgery that acute leptin can promote signaling in human blood vessels. In conclusion, in gBscl2-/- mice, leptin restores endothelial function via peroxisome proliferator activated receptor gamma-dependent decreases in Nox1. Furthermore, we provide the first evidence that vessels from aged patients remain leptin sensitive. These data reveal a new direct role of leptin receptors in the control of vascular homeostasis and present leptin as a potential therapy for the treatment of vascular disease associated with low leptin levels.
    Keywords:  endothelium; humans; leptin; mice; oxidative stress
  11. Nat Commun. 2019 Oct 28. 10(1): 4904
    Kusano T, Ehirchiou D, Matsumura T, Chobaz V, Nasi S, Castelblanco M, So A, Lavanchy C, Acha-Orbea H, Nishino T, Okamoto K, Busso N.
      Xanthine oxidoreductase has been implicated in cancer. Nonetheless, the role played by its two convertible forms, xanthine dehydrogenase (XDH) and oxidase (XO) during tumorigenesis is not understood. Here we produce XDH-stable and XO-locked knock-in (ki) mice to address this question. After tumor transfer, XO ki mice show strongly increased tumor growth compared to wild type (WT) and XDH ki mice. Hematopoietic XO expression is responsible for this effect. After macrophage depletion, tumor growth is reduced. Adoptive transfer of XO-ki macrophages in WT mice increases tumor growth. In vitro, XO ki macrophages produce higher levels of reactive oxygen species (ROS) responsible for the increased Tregs observed in the tumors. Blocking ROS in vivo slows down tumor growth. Collectively, these results indicate that the balance of XO/XDH plays an important role in immune surveillance of tumor development. Strategies that inhibit the XO form specifically may be valuable in controlling cancer growth.
  12. Biosci Rep. 2019 Oct 30. pii: BSR20192554. [Epub ahead of print]
    Li M, Zhang T, Wu X, Chen Y, Sun L.
      Microvesicles (MVs) were involved in the pathogenesis of many diseases, such as cardiovascular diseases and diabetes. Oxidative stress played a key role in the development and progression of diabetic nephropathy. Our aim of this study was to investigate whether high glucose could provoke microvesicles generation from podocytes and its potential mechanism. Mouse podocyte clone 5 (MPC-5) were stimulated by high glucose. The intracellular reactive oxygen species (ROS) of podocytes were measured by fluorescence microscopy with the probe of CM-H2DCFDA and MitoSOXTM. Antioxidants N-Acetyl-L-cysteine (NAC) and alpha lipoic acid (α-LA) were used to treat podocytes after high glucose stimulation. The rate of podocyte apoptosis was evaluated with Annexin V-FITC by flow cytometry. NOX4 expression was examined and siRNA were performed to explore the mechanism of MVs generation. The quantities of MVs from MPC-5 cells was significantly increased (P<0.05) by 4.6 times after 30 mM glucose stimulation, accompanied with double increased apoptosis. Cellular ROS generation was increased by high glucose at the peak of 48h stimulation. High glucose induced MVs was significantly decreased by 52.9% after pretreatment by antioxidant NAC. Nevertheless, Mitochondrial ROS in podocytes reached a peak at 4h stimulation, but specific antioxidant α-LA had no effect on the production of MVs (P>0.05). Levels of NOX4 mRNA and protein expression were significantly upregulated by high glucose (P<0.05). Podocyte-derived MVs by high glucose were eliminated by NOX4 siRNA. High glucose can provoke MVs generation from glomerular podocytes through ROS/NOX4 pathway, not from mitochondrial pathway.
    Keywords:  NOX4; high glucose; microvesicles; podocyte
  13. Antioxidants (Basel). 2019 Oct 29. pii: E518. [Epub ahead of print]8(11):
    Hack CT, Buck T, Bagnjuk K, Eubler K, Kunz L, Mayr D, Mayerhofer A.
      Recent studies showed that KGN cells, derived from a human granulosa cell tumor (GCT), express NADPH oxidase 4 (NOX4), an important source of H2O2. Transient receptor potential melastatin 2 (TRPM2) channel is a Ca2+ permeable cation channel that can be activated by H2O2 and plays an important role in cellular functions. It is also able to promote susceptibility to cell death. We studied expression and functionality of TRPM2 in KGN cells and examined GCT tissue microarrays (TMAs) to explore in vivo relevance. We employed live cell, calcium and mitochondrial imaging, viability assays, fluorescence activated cell sorting (FACS) analysis, Western blotting and immunohistochemistry. We confirmed that KGN cells produce H2O2 and found that they express functional TRPM2. H2O2 increased intracellular Ca2+ levels and N-(p-Amylcinnamoyl)anthranilic acid (ACA), a TRPM2 inhibitor, blocked this action. H2O2 caused mitochondrial fragmentation and apoptotic cell death, which could be attenuated by a scavenger (Trolox). Immunohistochemistry showed parallel expression of NOX4 and TRPM2 in all 73 tumor samples examined. The results suggest that GCTs can be endowed with a system that may convey susceptibility to cell death. If so, induction of oxidative stress may be beneficial in GCT therapy. Our results also imply a therapeutic potential for TRPM2 as a drug target in GCTs.
    Keywords:  Trolox; calcium channel; cell death; granulosa cell tumor; mitochondria; ovary
  14. Cancer Med. 2019 Oct 30.
    Zhao L, Chen X, Feng Y, Wang G, Nawaz I, Hu L, Liu P.
      COX7A1 is a subunit of cytochrome c oxidase, and plays an important role in the super-assembly that integrates peripherally into multi-unit heteromeric complexes in the mitochondrial respiratory chain. In recent years, some researchers have identified that COX7A1 is implicated in human cancer cell metabolism and therapy. In this study, we mainly explored the effect of COX7A1 on the cell viability of lung cancer cells. COX7A1 overexpression was induced by vector transfection in NCI-H838 cells. Cell proliferation, colony formation and cell apoptosis were evaluated in different groups. In addition, autophagy was analyzed by detecting the expression level of p62 and LC3, as well as the tandem mRFP-GFP-LC3 reporter assay respectively. Our results indicated that the overexpression of COX7A1 suppressed cell proliferation and colony formation ability, and promoted cell apoptosis in human non-small cell lung cancer cells. Besides, the overexpression of COX7A1 blocked autophagic flux and resulted in the accumulation of autophagosome via downregulation of PGC-1α and upregulation of NOX2. Further analysis showed that the effect of COX7A1 overexpression on cell viability was partly dependent of the inhibition of autophagy. Herein, we identified that COX7A1 holds a key position in regulating the development and progression of lung cancer by affecting autophagy. Although the crosstalk among COX7A1, PGC-1α and NOX2 needs further investigation, our study provides a novel insight into the therapeutic action of COX7A1 against human non-small cell lung cancer.
    Keywords:  COX7A1; NOX2; PGC-1α; autophagy; cell viability; non-small cell lung cancer
  15. Curr Neurovasc Res. 2019 Oct 23.
    Ji M, Wang Q, Zhao Y, Shi L, Zhou Z, Li Y.
      AIMS: To determine whether apelin in paraventricular nucleus (PVN) can be a therapeutic target for hypertension.BACKGROUND: Apelin is a specific endogenous ligand of orphan G protein-coupled receptor APJ.
    OBJECTIVE: This study was designed to determine how apelin chronically regulates sympathetic nerve activity and blood pressure in PVN of rats.
    METHODS: Apelin and APJ antagonist F13A were infused into PVN with osmotic minipumps. The NAD(P)H oxidase activity and superoxide anions levels in PVN of rats were determined by chemiluminescence.
    RESULTS: Infusion of apelin into PVN of Wistar-Kyoto (WKY) rats induced chronic increases in systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), plasma norepinephrine (NE) level, maximal depressor response to hexamethonium (Hex), NAD(P)H oxidase activity, superoxide anions levels, and Nox4 expression. Infusion of F13A into PVN of spontaneously hypertensive rats (SHRs) caused chronic decreases in SBP, DBP, MAP, plasma NE level, maximal depressor response to Hex, NAD(P)H oxidase activity, and superoxide anions levels. Hex, a sympathetic ganglion blocker, inhibited apelin-induced increases in SBP, DBP and MAP. SOD overexpression in PVN of SHRs inhibited the apelin-induced increase in SBP, DBP, MAP, plasma NE level, and maximal depressor response to Hex. PVN Nox4 knockdown also attenuated the apelin-induced increase in SBP, DBP, MAP, plasma NE level, and maximal depressor response to Hex. Chronic injection of F13A into PVN reduced fibrosis of renal artery, thoracic aorta, and heart in SHRs.
    CONCLUSION: These results demonstrated that in PVN apelin induced long-term high blood pressure and sympathetic activity via increasing oxidative stress.
    Keywords:  Apelin; F13A; blood pressure; oxidative stress; paraventricular nucleus; sympathetic activity