Abstract 362: Knockout of NADPH Oxidase 2 Improves Global Metabolism and Endothelial Function in Aging Mice

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Lampson M Fan ◽  
Li Geng ◽  
Jian-Mei Li
Keyword(s):  
Oxidative Stress ◽  
Endothelial Cells ◽  
Nadph Oxidase ◽  
Endothelial Function ◽  
Knockout Mice ◽  
Aging Process ◽  
Normal Aging ◽  
Wild Type ◽  
Middle Aged ◽  
Multiple Organs

Oxidative stress attributable to the activation of a Nox2-containing NADPH oxidase has been suggested to play a crucial role in the development of aging-associated vascular diseases. However, the mechanism of endothelial Nox2 activation in normal aging process remains unclear. In this study, we investigated the therapeutic potential of targeting Nox2 in improving global metabolism and endothelial function at old age by using age-matched wild-type and Nox2 knockout mice at 3-4 months (young); 11-12 months (middle aged) and 21-22 months (aging). Compared to young mice, middle-aged and ageing wild-type mice had significantly higher blood pressure, hyperglycaemia, hyperinsulinaemia. These were accompanied by oxidative stress in multiple organs including the lung, the liver, the heart and the vessels. The vessel motor function was examined in an organ bath using aortas isolated from these mice. Endothelium-dependent vessel relaxation to acetylcholine was significantly impaired in aortas of wild-type aging mice, and this was accompanied by increased expressions of Nox2 and markers of inflammation, activation of MAPK and Akt and decreased insulin receptor expression and function. However, these aging-associated disorders in aortas were significantly reduced by knocking out Nox2 in mice. In response to high glucose plus high insulin challenge, coronary microvascular endothelial cells isolated from wild-type mice displayed significantly increased Nox2 expression, oxidative stress and cell senescence, e.g. increased p53 expression and β-galactosidase activity. However, these responses were absent or significantly reduced in the endothelial cells isolated from Nox2 knockout mice. In conclusion, metabolic disorders in particular hyperglycaemia and insulin resistance play an important role in mediating Nox2 activation and oxidative stress in multiple organs in aging. Nox2 is involved in normal aging process-associated vascular inflammation and oxidative damage of endothelial dysfunction.

scholarly journals Oxidative Stress after Subarachnoid Hemorrhage in gp91phox Knockout Mice

2007 ◽  
Vol 34 (3) ◽  
pp. 356-361 ◽  
Author(s):  
Shimin Liu ◽  
Jiping Tang ◽  
Robert P Ostrowski ◽  
Elena Titova ◽  
Cara Monroe ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Subarachnoid Hemorrhage ◽  
Brain Injury ◽  
Mortality Rate ◽  
Nadph Oxidase ◽  
Water Content ◽  
Knockout Mice ◽  
Early Brain Injury ◽  
Superoxide Production ◽  
Wild Type

Background:Oxidative stress largely contributes to early brain injury after subarachnoid hemorrhage (SAH). One of the major sources of reactive oxygen species is NADPH oxidase, upregulated after SAH. We hypothesized that NADPH oxidase-induced oxidative stress plays a major causative role in early brain injury after SAH.Methods:Using gp91phox knockout (ko) and wild-type (wt) mice, we studied early brain injury in the endovascular perforation model of SAH. Mortality rate, cerebral edema, oxidative stress, and superoxide production were measured at 24 h after SAH. Neurological evaluation was done at 23 h after SAH surgery.Results:Genotyping confirmed the existence of a nonfunctional gp91phox gene in the ko mice. CBF measurements did not show differences in SAH-induced acute ischemia between ko and wt mice. SAH caused a significant increase of water content in the ipsilateral hemisphere as well as an increase of Malondialdehyde (MDA) levels and superoxide production. There were no significant differences in post-SAH mortality rate, brain water content and the intensity of the oxidative stress between knockout and wild type groups of mice.Conclusions:Our results suggest that gp91phox is not critically important to the early brain injury after SAH. An adaptive compensatory mechanism for free radical production in knockout mice is discussed.

scholarly journals Sortilin evokes endothelial dysfunction and arterial hypertension through the dysregulation of sphingolipid metabolism and oxidative stress

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
P Di Pietro ◽  
M Oliveti ◽  
E Sommella ◽  
A Damato ◽  
A Puca ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Endothelial Cells ◽  
Nadph Oxidase ◽  
Endothelial Function ◽  
Acid Sphingomyelinase ◽  
Mesenteric Arteries ◽  
Hypertensive Patients ◽  
Arterial Blood ◽  
Sphingosine 1 Phosphate

Abstract Background Sortilin, a member of vacuolar protein sorting domain family Vps10, has been positively correlated with vascular and metabolic disorders in humans. Previous study has shown that, in response to Fas receptor stimulation, sortilin together with acid sphingomyelinase (ASMase) promote the clustering of lipid rafts and subsequent activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in coronary endothelial cells. However, whether sortilin plays a role in endothelial cells function is currently unknown. Purpose To assess whether sortilin per se was able to influence vascular function, thereby contributing to the pathogenesis of cardiovascular diseases. Methods Pressure myography was used to study vascular reactivity of mesenteric arteries. To investigate the involvement of acid sphingomyelinase (ASM), we performed gene silencing approach and fluorometric activity assay. NADPH oxidase lucigenin assay was used to evaluate oxidative stress in endothelial cells and resistance vessels. The effects of circulating sortilin on cardiovascular system was evaluated by systemic delivery of recombinant sortilin protein to wild-type (WT), sphingosine-1-phosphate receptor 3 (S1P3) and NADPH oxidase 2 (gp91phox/NOX2) deficient mice. Systolic arterial blood pressure (SBP) was noninvasively registered in conscious mice by tail-cuff blood monitoring. Finally, to explore the translational relevance of sortilin, we measured sortilin and NOX2 soluble derived peptide levels using ELISA and quantified sphingosine-1-phosphate (S1P) by liquid chromatography–tandem mass spectrometry (LC-MS/MS) in plasma of hypertensive patients. Results Here we demonstrated that sortilin evoked endothelial dysfunction in mesenteric arteries due to increased NADPH oxidase-derived oxidative stress. Knockdown of ASM successfully prevented impairment of endothelial function. Using the inhibitor of sphingosine kinase type 1 (SphK1), sortilin failed to evoke endothelial impairment as well as NADPH oxidase activation. In endothelial cells, sortilin induced S1P-dependent activation of Rac1/NOX2 signaling axis, which was prevented by TY-52156, an antagonist of lysosphingolipid receptor S1P3. In vivo sortilin administration induced arterial hypertension in WT mice. In contrast, genetic deletion of S1P3 and gp91phox/NOX2 resulted in preservation of endothelial function and SBP unchanged levels after 14 days of systemic sortilin administration. Finally, to translate these research findings into a clinical setting, we found that hypertensive patients have higher plasma levels of sortilin, ASMase, S1P and soluble NOX2 derived peptide than normotensive subjects. Conclusions These results demonstrate the pathologic role of sortilin in the modulation of endothelial function and arterial blood pressure, suggesting that sortilin and its mediators might represent novel therapeutic targets in vascular diseases and hypertension. Funding Acknowledgement Type of funding source: None

scholarly journals Vascular endothelial function and oxidative stress are related to dietary niacin intake among healthy middle-aged and older adults

2014 ◽  
Vol 116 (2) ◽  
pp. 156-163 ◽  
Author(s):  
Rachelle E. Kaplon ◽  
Lindsey B. Gano ◽  
Douglas R. Seals
Keyword(s):  
Oxidative Stress ◽  
Older Adults ◽  
Nadph Oxidase ◽  
Endothelial Function ◽  
Brachial Artery ◽  
Antioxidant Vitamin ◽  
Vascular Endothelial ◽  
Vascular Endothelial Function ◽  
Middle Aged ◽  
And Oxidative Stress

We tested the hypothesis that vascular endothelial function and oxidative stress are related to dietary niacin intake among healthy middle-aged and older adults. In 127 men and women aged 48–77 yr, brachial artery flow-mediated dilation (FMD) was positively related to dietary niacin intake [%change (Δ): r = 0.20, P < 0.05; mmΔ: r = 0.25, P < 0.01]. In subjects with above-average dietary niacin intake (≥22 mg/day, NHANES III), FMD was 25% greater than in subjects with below-average intake ( P < 0.05). Stepwise linear regression revealed that dietary niacin intake (above vs. below average) was an independent predictor of FMD (%Δ: β = 1.8; mmΔ: β = 0.05, both P < 0.05). Plasma oxidized low-density lipoprotein, a marker of systemic oxidative stress, was inversely related to niacin intake ( r = −0.23, P < 0.05) and was lower in subjects with above- vs. below-average niacin intake (48 ± 2 vs. 57 ± 2 mg/dl, P < 0.01). Intravenous infusion of the antioxidant vitamin C improved brachial FMD in subjects with below-average niacin intake ( P < 0.001, n = 33), but not above-average ( P > 0.05, n = 20). In endothelial cells sampled from the brachial artery of a subgroup, dietary niacin intake was inversely related to nitrotyrosine, a marker of peroxynitrite-mediated oxidative damage ( r = −0.30, P < 0.05, n = 55), and expression of the prooxidant enzyme, NADPH oxidase ( r = −0.44, P < 0.01, n = 37), and these markers were lower in subjects with above- vs. below-average niacin intake [nitrotyrosine: 0.39 ± 0.05 vs. 0.56 ± 0.07; NADPH oxidase: 0.38 ± 0.05 vs. 0.53 ± 0.05 (ratio to human umbilical vein endothelial cell control), both P < 0.05]. Our findings support the hypothesis that higher dietary niacin intake is associated with greater vascular endothelial function related to lower systemic and vascular oxidative stress among healthy middle-aged and older adults.

Abstract 123: Age-Related Endothelial Senescence is Driven by Thrombospondin-1-Activated NADPH Oxidase Nox1

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Daniel N Meijles ◽  
Imad Al Ghouleh ◽  
Sanghamitra Sahoo ◽  
Jefferson H Amaral ◽  
Heather Knupp ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nadph Oxidase ◽  
Vascular Diseases ◽  
Dependent Manner ◽  
Wild Type ◽  
Molecular Control ◽  
Redox Biology ◽  
Age Related ◽  
P53 Activation

Organismal aging represents an independent risk factor underlying many vascular diseases, including systemic and pulmonary hypertension, and atherosclerosis. While the mechanisms driving aging are largely elusive, a steady persistent increase in tissue oxidative stress has been associated with senescence. Previously we showed TSP1 elicits NADPH oxidase (Nox)-dependent vascular smooth muscle cell oxidative stress. However mechanisms by which TSP1 affects endothelial redox biology are unknown. Here, we tested the hypothesis that TSP1 induces endothelial oxidative stress-linked senescence in aging. Using rapid autopsy disease-free human pulmonary (PA) artery, we identified a significant positive correlation between age, protein levels of TSP1, Nox1 and the cell-cycle repressor p21cip (p<0.05). Age also positively associated with increased Amplex Red-detected PA hydrogen peroxide levels (p<0.05). Moreover, treatment of human PA endothelial cells (HPAEC) with TSP1 (2.2nM; 24h) increased expression (~1.9 fold; p<0.05) and activation of Nox1 (~1.7 fold; p<0.05) compared to control, as assessed by Western blot and SOD-inhibitable cytochrome c reduction. Western blotting and immunofluorescence showed a TSP1-mediated increase in p53 activation, indicative of the DNA damage response. Moreover, TSP1 significantly increased HPAEC senescence in a p53/p21cip/Rb-dependent manner, as assessed by immunofluorescent detection of subcellular localization and senescence-associated β-galactosidase staining. To explore this pathway in vivo, middle-aged (8-10 month) wild-type and TSP1-null mice were utilized. In the TSP1-null, reduced lung senescence, oxidative stress, Nox1 levels and p21cip expression were observed compared to wild-type supporting findings in human samples and cell experiments. Finally, prophylactic treatment with specific Nox1 inhibitor NoxA1ds (10μM) attenuated TSP1-induced HPAEC ROS, p53 activation, p21cip expression and senescence. Taken together, our results provide molecular insight into the functional interplay between TSP1 and Nox1 in the regulation of endothelial senescence, with implications for molecular control of the aging process.

scholarly journals Protective Role of Endogenous Kallistatin in Vascular Injury and Senescence by Inhibiting Oxidative Stress and Inflammation

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Julie Chao ◽  
Youming Guo ◽  
Lee Chao
Keyword(s):  
Oxidative Stress ◽  
Endothelial Cells ◽  
Nadph Oxidase ◽  
Vascular Injury ◽  
Oxidase Activity ◽  
Sirtuin 1 ◽  
Mouse Lung ◽  
Heparin Binding ◽  
Diabetic Mice ◽  
Nadph Oxidase Activity

Kallistatin was identified in human plasma as a tissue kallikrein-binding protein and a serine proteinase inhibitor. Kallistatin exerts pleiotropic effects on angiogenesis, oxidative stress, inflammation, apoptosis, fibrosis, and tumor growth. Kallistatin levels are markedly reduced in patients with coronary artery disease, sepsis, diabetic retinopathy, inflammatory bowel disease, pneumonia, and cancer. Moreover, plasma kallistatin levels are positively associated with leukocyte telomere length in young African Americans, indicating the involvement of kallistatin in aging. In addition, kallistatin treatment promotes vascular repair by increasing the migration and function of endothelial progenitor cells (EPCs). Kallistatin via its heparin-binding site antagonizes TNF-α-induced senescence and superoxide formation, while kallistatin’s active site is essential for inhibiting miR-34a synthesis, thus elevating sirtuin 1 (SIRT1)/eNOS synthesis in EPCs. Kallistatin inhibits oxidative stress-induced cellular senescence by upregulating Let-7g synthesis, leading to modulate Let-7g-mediated miR-34a-SIRT1-eNOS signaling pathway in human endothelial cells. Exogenous kallistatin administration attenuates vascular injury and senescence in association with increased SIRT1 and eNOS levels and reduced miR-34a synthesis and NADPH oxidase activity, as well as TNF-α and ICAM-1 expression in the aortas of streptozotocin- (STZ-) induced diabetic mice. Conversely, endothelial-specific depletion of kallistatin aggravates vascular senescence, oxidative stress, and inflammation, with further reduction of Let-7g, SIRT1, and eNOS and elevation of miR-34a in mouse lung endothelial cells. Furthermore, systemic depletion of kallistatin exacerbates aortic injury, senescence, NADPH oxidase activity, and inflammatory gene expression in STZ-induced diabetic mice. These findings indicate that endogenous kallistatin displays a novel role in protection against vascular injury and senescence by inhibiting oxidative stress and inflammation.

scholarly journals Activation of endothelial NADPH oxidase during normoxic lung ischemia is KATP channel dependent

2005 ◽  
Vol 289 (6) ◽  
pp. L954-L961 ◽  
Author(s):  
Qunwei Zhang ◽  
Ikuo Matsuzaki ◽  
Shampa Chatterjee ◽  
Aron B. Fisher
Keyword(s):  
Endothelial Cells ◽  
Membrane Potential ◽  
Endothelial Cell ◽  
Cell Membrane ◽  
Nadph Oxidase ◽  
Membrane Depolarization ◽  
Fluorescence Probes ◽  
Ros Generation ◽  
Wild Type ◽  
Channel Dependent

Previous studies have shown endothelial cell membrane depolarization and generation of reactive oxygen species (ROS) in endothelial cells with abrupt reduction in shear stress (ischemia). This study evaluated the role of ATP-sensitive potassium (KATP) channels and NADPH oxidase in the ischemic response by using Kir6.2−/− and gp91phox−/− mice. To evaluate ROS generation, we subjected isolated perfused mouse lungs labeled with 2′,7′-dichlorodihydrofluorescein (DCF), hydroethidine (HE), or diphenyl-1-pyrenylphosphine (DPPP) to control perfusion followed by global ischemia. In wild-type C57BL/6J mice, imaging of subpleural endothelial cells showed a time-dependent increase in intensity for all three fluorescence probes with ischemia, which was blocked by preperfusion with cromakalim (a KATP channel agonist) or diphenyleneiodonium (DPI, a flavoprotein inhibitor). Endothelial cell fluorescence with bis-oxonol, a membrane potential probe, increased during lung ischemia indicating cell membrane depolarization. The change in membrane potential with ischemia in lungs of gp91phox−/− mice was similar to wild type, but ROS generation did not occur. Lungs from Kir6.2−/− showed marked attenuation of the change in both membrane potential and ROS production. Thus membrane depolarization during lung ischemia requires the presence of a KATP channel and is required for activation of NADPH oxidase and endothelial ROS generation.

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