scholarly journals Traumatic Brain Injury Causes Endothelial Dysfunction in the Systemic Microcirculation through Arginase-1–Dependent Uncoupling of Endothelial Nitric Oxide Synthase

2017 ◽  
Vol 34 (1) ◽  
pp. 192-203 ◽  
Author(s):  
Nuria Villalba ◽  
Adrian M. Sackheim ◽  
Ivette A. Nunez ◽  
David C. Hill-Eubanks ◽  
Mark T. Nelson ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Endothelial Dysfunction ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Arginase 1 ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Injury Causes

Endothelial Nitric Oxide Synthase Mediates Arteriolar Vasodilatation after Traumatic Brain Injury in Mice

2015 ◽  
Vol 32 (10) ◽  
pp. 731-738 ◽  
Author(s):  
Susanne M. Schwarzmaier ◽  
Nicole A. Terpolilli ◽  
Ari Dienel ◽  
Micaela Gallozzi ◽  
Reinhard Schinzel ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

scholarly journals Endothelial PPAR-γ provides vascular protection from IL-1β-induced oxidative stress

2016 ◽  
Vol 310 (1) ◽  
pp. H39-H48 ◽  
Author(s):  
Masashi Mukohda ◽  
Madeliene Stump ◽  
Pimonrat Ketsawatsomkron ◽  
Chunyan Hu ◽  
Frederick W. Quelle ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Nitric Oxide Synthase ◽  
Transgenic Mice ◽  
Stress Responses ◽  
Endothelial Nitric Oxide Synthase ◽  
Ppar Γ ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Loss of peroxisome proliferator-activated receptor (PPAR)-γ function in the vascular endothelium enhances atherosclerosis and NF-κB target gene expression in high-fat diet-fed apolipoprotein E-deficient mice. The mechanisms by which endothelial PPAR-γ regulates inflammatory responses and protects against atherosclerosis remain unclear. To assess functional interactions between PPAR-γ and inflammation, we used a model of IL-1β-induced aortic dysfunction in transgenic mice with endothelium-specific overexpression of either wild-type (E-WT) or dominant negative PPAR-γ (E-V290M). IL-1β dose dependently decreased IκB-α, increased phospho-p65, and increased luciferase activity in the aorta of NF-κB-LUC transgenic mice. IL-1β also dose dependently reduced endothelial-dependent relaxation by ACh. The loss of ACh responsiveness was partially improved by pretreatment of the vessels with the PPAR-γ agonist rosiglitazone or in E-WT. Conversely, IL-1β-induced endothelial dysfunction was worsened in the aorta from E-V290M mice. Although IL-1β increased the expression of NF-κB target genes, NF-κB p65 inhibitor did not alleviate endothelial dysfunction induced by IL-1β. Tempol, a SOD mimetic, partially restored ACh responsiveness in the IL-1β-treated aorta. Notably, tempol only modestly improved protection in the E-WT aorta but had an increased protective effect in the E-V290M aorta compared with the aorta from nontransgenic mice, suggesting that PPAR-γ-mediated protection involves antioxidant effects. IL-1β increased ROS and decreased the phospho-endothelial nitric oxide synthase (Ser1177)-to-endothelial nitric oxide synthase ratio in the nontransgenic aorta. These effects were completely abolished in the aorta with endothelial overexpression of WT PPAR-γ but were worsened in the aorta with E-V290M even in the absence of IL-1β. We conclude that PPAR-γ protects against IL-1β-mediated endothelial dysfunction through a reduction of oxidative stress responses but not by blunting IL-1β-mediated NF-κB activity.

scholarly journals Potential pitfalls in analyzing structural uncoupling of eNOS: aging is not associated with increased enzyme monomerization

2019 ◽  
Vol 316 (1) ◽  
pp. H80-H88 ◽  
Author(s):  
Fumin Chang ◽  
Sheila Flavahan ◽  
Nicholas A. Flavahan
Keyword(s):  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Normal Activity ◽  
Aortic Endothelial Cells ◽  
Relative Expression ◽  
Fischer 344 ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Homodimer formation is essential for the normal activity of endothelial nitric oxide synthase (eNOS). Structural uncoupling of eNOS, with generation of enzyme monomers, is thought to contribute to endothelial dysfunction in several vascular disorders, including aging. However, low-temperature SDS-PAGE of healthy arteries has revealed considerable variation between studies in the relative expression of eNOS dimers and monomers. While assessing structural uncoupling of eNOS in aging arteries, we identified methodological pitfalls that might contribute to such variation. Therefore, using human cultured aortic endothelial cells and aortas from young and aged Fischer-344 rats, we investigated optimal approaches for analyzing the expression of eNOS monomers and dimers. The results demonstrated that published differences in treatment of cell lysates can significantly impact the relative expression of several eNOS species, including denatured monomers, partially folded monomers, dimers, and higher-order oligomers. In aortas, experiments initially confirmed a large increase in eNOS monomers in aging arteries, consistent with structural uncoupling. However, these monomers were actually endogenous IgG, which, under these conditions, has mobility similar to eNOS monomers. Increased IgG levels in aged aortas likely reflect the aging-induced disruption of endothelial junctions and increased arterial penetration of IgG. After removal of the IgG signal, there were low levels of eNOS monomers in young arteries, which were not significantly different in aged arteries. Therefore, structural uncoupling of eNOS is not a prominent feature in young healthy arteries, and the process is not increased by aging. The study also identifies optimal approaches to analyze eNOS dimers and monomers. NEW & NOTEWORTHY Structural uncoupling of endothelial nitric oxide synthase (eNOS) is considered central to endothelial dysfunction. However, reported levels of eNOS dimers and monomers vary widely, even in healthy arteries. We demonstrate that sample processing can alter relative levels of eNOS species. Moreover, endothelial dysfunction in aging aortas results in IgG accumulation, which, because of similar mobility to eNOS monomers, could be misinterpreted as structural uncoupling. Indeed, enzyme monomerization is not prominent in young or aging arteries.

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