http://hdl.handle.net/2144/2478 2013-05-19T11:59:54Z 2013-05-19T11:59:54Z Jourd'heuil, Frances L. Lowery, Anthony M. Melton, Elaina M. Mnaimneh, Sanie Bryan, Nathan S. Fernandez, Bernadette O. Park, Joo-Ho Ha, Chung-Eun Bhagavan, Nadhipuram V. Feelisch, Martin Jourd'heuil, David http://hdl.handle.net/2144/3432 2012-01-13T07:00:55Z 2010-12-21T00:00:00Z

Redox-Sensitivity and Site-Specificity of S- and N- Denitrosation in Proteins Jourd'heuil, Frances L.; Lowery, Anthony M.; Melton, Elaina M.; Mnaimneh, Sanie; Bryan, Nathan S.; Fernandez, Bernadette O.; Park, Joo-Ho; Ha, Chung-Eun; Bhagavan, Nadhipuram V.; Feelisch, Martin; Jourd'heuil, David BACKGROUND. S-nitrosation - the formation of S-nitrosothiols (RSNOs) at cysteine residues in proteins - is a posttranslational modification involved in signal transduction and nitric oxide (NO) transport. Recent studies would also suggest the formation of N-nitrosamines (RNNOs) in proteins in vivo, although their biological significance remains obscure. In this study, we characterized a redox-based mechanism by which N-nitroso-tryptophan residues in proteins may be denitrosated. METHODOLOGY/PRINCIPAL FINDINGS. The denitrosation of N-acetyl-nitroso Trp (NANT) by glutathione (GSH) required molecular oxygen and was inhibited by superoxide dismutase (SOD). Transnitrosation to form S-nitrosoglutathione (GSNO) was observed only in the absence of oxygen or presence of SOD. Protein denitrosation by GSH was studied using a set of mutant recombinant human serum albumin (HSA). Trp-214 and Cys-37 were the only two residues nitrosated by NO under aerobic conditions. Nitroso-Trp-214 in HSA was insensitive to denitrosation by GSH or ascorbate while denitrosation at Cys-37 was evident in the presence of GSH but not ascorbate. GSH-dependent denitrosation of Trp-214 was restored in a peptide fragment of helix II containing Trp-214. Finally, incubation of cell lysates with NANT revealed a pattern of protein nitrosation distinct from that observed with GSNO. CONCLUSIONS. We propose that the denitrosation of nitrosated Trp by GSH occurs through homolytic cleavage of nitroso Trp to NO and a Trp aminyl radical, driven by the formation of superoxide derived from the oxidation of GSH to GSSG. Overall, the accessibility of Trp residues to redox-active biomolecules determines the stability of protein-associated nitroso species such that in the case of HSA, N-nitroso-Trp-214 is insensitive to denitrosation by low-molecular-weight antioxidants. Moreover, RNNOs can generate free NO and transfer their NO moiety in an oxygen-dependent fashion, albeit site-specificities appear to differ markedly from that of RSNOs.

2010-12-21T00:00:00Z O'Shea, Karen M Chess, David J Khairallah, Ramzi J Hecker, Peter A Lei, Biao Walsh, Kenneth Des Rosiers, Christine Stanley, William C http://hdl.handle.net/2144/3430 2012-01-13T07:00:54Z 2010-09-06T00:00:00Z

ω-3 Polyunsaturated Fatty Acids Prevent Pressure Overload-Induced Ventricular Dilation and Decrease in Mitochondrial Enzymes Despite no Change in Adiponectin O'Shea, Karen M; Chess, David J; Khairallah, Ramzi J; Hecker, Peter A; Lei, Biao; Walsh, Kenneth; Des Rosiers, Christine; Stanley, William C BACKGROUND Pathological left ventricular (LV) hypertrophy frequently progresses to dilated heart failure with suppressed mitochondrial oxidative capacity. Dietary marine ω-3 polyunsaturated fatty acids (ω-3 PUFA) up-regulate adiponectin and prevent LV dilation in rats subjected to pressure overload. This study 1) assessed the effects of ω-3 PUFA on LV dilation and down-regulation of mitochondrial enzymes in response to pressure overload; and 2) evaluated the role of adiponectin in mediating the effects of ω-3 PUFA in heart. METHODS Wild type (WT) and adiponectin-/- mice underwent transverse aortic constriction (TAC) and were fed standard chow ± ω-3 PUFA for 6 weeks. At 6 weeks, echocardiography was performed to assess LV function, mice were terminated, and mitochondrial enzyme activities were evaluated. RESULTS TAC induced similar pathological LV hypertrophy compared to sham mice in both strains on both diets. In WT mice TAC increased LV systolic and diastolic volumes and reduced mitochondrial enzyme activities, which were attenuated by ω-3 PUFA without increasing adiponectin. In contrast, adiponectin-/- mice displayed no increase in LV end diastolic and systolic volumes or decrease in mitochondrial enzymes with TAC, and did not respond to ω-3 PUFA. CONCLUSION These findings suggest ω-3 PUFA attenuates cardiac pathology in response to pressure overload independent of an elevation in adiponectin.

2010-09-06T00:00:00Z Grenz, Almut Osswald, Hartmut Eckle, Tobias Yang, Dan Zhang, Hua Tran, Zung Vu Klingel, Karin Ravid, Katya Eltzschig, Holger K http://hdl.handle.net/2144/3431 2012-01-13T07:00:55Z 2008-06-24T00:00:00Z

The Reno-Vascular A2B Adenosine Receptor Protects the Kidney from Ischemia Grenz, Almut; Osswald, Hartmut; Eckle, Tobias; Yang, Dan; Zhang, Hua; Tran, Zung Vu; Klingel, Karin; Ravid, Katya; Eltzschig, Holger K BACKGROUND. Acute renal failure from ischemia significantly contributes to morbidity and mortality in clinical settings, and strategies to improve renal resistance to ischemia are urgently needed. Here, we identified a novel pathway of renal protection from ischemia using ischemic preconditioning (IP). METHODS AND FINDINGS. For this purpose, we utilized a recently developed model of renal ischemia and IP via a hanging weight system that allows repeated and atraumatic occlusion of the renal artery in mice, followed by measurements of specific parameters or renal functions. Studies in gene-targeted mice for each individual adenosine receptor (AR) confirmed renal protection by IP in A1−/−, A2A−/−, or A3AR−/− mice. In contrast, protection from ischemia was abolished in A2BAR−/− mice. This protection was associated with corresponding changes in tissue inflammation and nitric oxide production. In accordance, the A2BAR-antagonist PSB1115 blocked renal protection by IP, while treatment with the selective A2BAR-agonist BAY 60–6583 dramatically improved renal function and histology following ischemia alone. Using an A2BAR-reporter model, we found exclusive expression of A2BARs within the reno-vasculature. Studies using A2BAR bone-marrow chimera conferred kidney protection selectively to renal A2BARs. CONCLUSIONS. These results identify the A2BAR as a novel therapeutic target for providing potent protection from renal ischemia. Using gene-targeted mice, Holger Eltzschig and colleagues identify the A2B adenosine receptor as a novel therapeutic target for providing protection from renal ischemia.

2008-06-24T00:00:00Z Sanoudou, D Duka, A Drosatos, K Hayes, K C Zannis, V I http://hdl.handle.net/2144/3331 2012-01-12T07:00:47Z 2009-12-01T00:00:00Z

Role of Esrrg in the Fibrate-Mediated Regulation of Lipid Metabolism Genes in Human ApoA-I Transgenic Mice Sanoudou, D; Duka, A; Drosatos, K; Hayes, K C; Zannis, V I We have used a new ApoA-I transgenic mouse model to identify by global gene expression profiling, candidate genes that affect lipid and lipoprotein metabolism in response to fenofibrate treatment. Multilevel bioinformatical analysis and stringent selection criteria (2-fold change, 0% false discovery rate) identified 267 significantly changed genes involved in several molecular pathways. The fenofibrate-treated group did not have significantly altered levels of hepatic human APOA-I mRNA and plasma ApoA-I compared with the control group. However, the treatment increased cholesterol levels to 1.95-fold mainly due to the increase in high-density lipoprotein (HDL) cholesterol. The observed changes in HDL are associated with the upregulation of genes involved in phospholipid biosynthesis and lipid hydrolysis, as well as phospholipid transfer protein. Significant upregulation was observed in genes involved in fatty acid transport and β-oxidation, but not in those of fatty acid and cholesterol biosynthesis, Krebs cycle and gluconeogenesis. Fenofibrate changed significantly the expression of seven transcription factors. The estrogen receptor-related gamma gene was upregulated 2.36-fold and had a significant positive correlation with genes of lipid and lipoprotein metabolism and mitochondrial functions, indicating an important role of this orphan receptor in mediating the fenofibrate-induced activation of a specific subset of its target genes.

2009-12-01T00:00:00Z