scholarly journals Endothelin-1–Mediated Increase in Reactive Oxygen Species and NADPH Oxidase Activity in Hearts of Aryl Hydrocarbon Receptor (AhR) Null Mice

2005 ◽  
Vol 88 (1) ◽  
pp. 265-273 ◽  
Author(s):  
Amie K. Lund ◽  
Steven L. Peterson ◽  
Graham S. Timmins ◽  
Mary K. Walker
2010 ◽  
Vol 40 (13) ◽  
pp. 1531-1538 ◽  
Author(s):  
Natalia Guiñazú ◽  
Eugenio Antonio Carrera-Silva ◽  
María Cecilia Becerra ◽  
Andrea Pellegrini ◽  
Inés Albesa ◽  
...  

2006 ◽  
Vol 290 (1) ◽  
pp. R96-R104 ◽  
Author(s):  
Zhiwei Yang ◽  
Laureano D. Asico ◽  
Peiying Yu ◽  
Zheng Wang ◽  
John E. Jones ◽  
...  

Activation of D1-like receptors (D1 and/or D5) induces antioxidant responses; however, the mechanism(s) involved in their antioxidant actions are not known. We hypothesized that stimulation of the D5 receptor inhibits NADPH oxidase activity, and thus the production of reactive oxygen species (ROS). We investigated this issue in D5 receptor-deficient (D5−/−) and wild-type (D5+/+) mice. NADPH oxidase protein expression (gp91phox, p47phox, and Nox 4) and activity in kidney and brain, as well as plasma thiobarbituric acid-reactive substances (TBARS) were higher in D5−/− than in D5+/+ mice. Furthermore, apocynin, an NADPH oxidase inhibitor, normalized blood pressure, renal NADPH oxidase activity, and plasma TBARS in D5−/− mice. In HEK-293 cells that heterologously expressed human D5 receptor, its agonist fenoldopam decreased NADPH oxidase activity, expression of one of its subunits (gp91phox), and ROS production. The inhibitory effect of the D5 receptor activation on NADPH oxidase activity was independent of cAMP/PKA but was partially dependent on phospholipase D2. The ability of D5 receptor stimulation to decrease ROS production may explain, in part, the antihypertensive action of D5 receptor activation.


2013 ◽  
Vol 206 (2) ◽  
pp. 186-193 ◽  
Author(s):  
Sandrine Derochette ◽  
Thierry Franck ◽  
Ange Mouithys-Mickalad ◽  
Justine Ceusters ◽  
Ginette Deby-Dupont ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Wentao Hu ◽  
Lin Zhu ◽  
Weiwei Pei ◽  
Shuxian Pan ◽  
Ziyang Guo ◽  
...  

Radioresistance is the major obstacle in the radiotherapy of the malignant melanoma. Thus, it is of importance to increase the radiosensitivity of melanoma cells. In the present study, the radioresistant melanoma cell line OCM-1 with inducible overexpression of Ras-related C3 botulinum toxin substrate 2 was established based on a radiation-inducible early growth response gene (Egr-1) promoter. The effects of Ras-related C3 botulinum toxin substrate 2 overexpression on the radiosensitivity of melanoma cells exposed to either X-rays or carbon ion beams were evaluated in cultured cells as well as xenograft tumor models. In addition, both reactive oxygen species yield and the NADPH oxidase activity were measured in the irradiated melanoma cells. It was found that the radiation-inducible overexpression of Ras-related C3 botulinum toxin substrate 2 sensitized the melanoma cells to both X-rays and carbon ion irradiation by enhancing the NADPH oxidase activity and the subsequent reactive oxygen species production. Besides, the overexpression of Ras-related C3 botulinum toxin substrate 2 enhanced the tumor-killing effect of radiotherapy in xenograft tumors significantly. The results of this study indicate that Ras-related C3 botulinum toxin substrate 2 is promising in increasing the radiosensitivity of melanoma cells, which provides experimental evidence and theoretical basis for clinical radiosensitization of the malignant melanoma.


2012 ◽  
Vol 302 (3) ◽  
pp. C597-C604 ◽  
Author(s):  
Rita M. Maalouf ◽  
Assaad A. Eid ◽  
Yves C. Gorin ◽  
Karen Block ◽  
Gladys Patricia Escobar ◽  
...  

Oxidative stress contributes to diabetic cardiomyopathy. This study explored the role of the NADPH oxidase Nox4 as a source of reactive oxygen species (ROS) involved in the development of diabetic cardiomyopathy. Phosphorothioated antisense (AS) or sense (S) oligonucleotides for Nox4 were administered for 2 wk to rats made diabetic by streptozotocin. NADPH oxidase activity, ROS generation, and the expression of Nox4, but Nox1 or Nox2, were increased in left ventricular tissue of the diabetic rats. Expression of molecular markers of hypertrophy and myofibrosis including fibronectin, collagen, α-smooth muscle actin, and β-myosin heavy chain were also increased. These parameters were attenuated by the administration of AS but not S Nox4. Moreover, the impairment of contractility observed in diabetic rats was prevented in AS- but not S-treated animals. Exposure of cultured cardiac myocytes to 25 mM glucose [high glucose (HG)] increased NADPH oxidase activity, the expression of Nox4, and molecular markers of cardiac injury. These effects of HG were prevented in cells infected with adenoviral vector containing a dominant negative form of Nox4. This study provides strong evidence that Nox4 is an important source of ROS in the left ventricle and that Nox4-derived ROS contribute to cardiomyopathy at early stages of type 1 diabetes.


Endocrinology ◽  
2008 ◽  
Vol 149 (11) ◽  
pp. 5643-5653 ◽  
Author(s):  
Javad Habibi ◽  
Adam Whaley-Connell ◽  
Melvin R. Hayden ◽  
Vincent G. DeMarco ◽  
Rebecca Schneider ◽  
...  

Emerging evidence indicates that pancreatic tissue expresses all components of the renin-angiotensin system. However, the functional role is not well understood. This investigation examined renin inhibition on pancreas structure/function in the transgenic Ren2 rat harboring the mouse renin gene, a model of tissue renin overexpression. Renin is the rate-limiting step in the generation of angiotensin II (Ang II), which stimulates the generation of reactive oxygen species in a variety of tissues. Overexpression of renin in Ren2 rats results in hypertension, insulin resistance, and cardiovascular and renal damage. Young (6–7 wk old) insulin-resistant male Ren2 and age-matched insulin sensitive Sprague Dawley rats were treated with the renin inhibitor, aliskiren (50 mg/kg·d by ip injection), or placebo for 21 d. At 21 d, the Ren2 demonstrated insulin resistance with increased islet insulin, Ang II, and reduced total insulin receptor substrate (IRS)-1, IRS-2, and Akt immunostaining. There was increased islet nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and subunits (p47phox and Rac1) as well as increased nitrotyrosine immunostaining (each P < 0.05). These functional abnormalities were associated with a disordered islet architecture; increased islet-exocrine interface, pericapillary fibrosis, and structurally abnormal mitochondria and content in endocrine and exocrine pancreas. In vivo treatment with aliskiren normalized systemic insulin resistance and islet insulin, Ang II, NADPH oxidase activity/subunits, and nitrotyrosine and improved total IRS-1 and Akt phosphorylation (each P < 0.05) as well as islet/exocrine structural abnormalities. Collectively, these data suggest that pancreatic functional/structural changes are driven, in part, by tissue renin-angiotensin system-mediated increases in NADPH oxidase and reactive oxygen species generation, abnormalities attenuated with direct renin inhibition.


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