Difference between revisions of "Rodriguez-Juarez 2007 Biochem J"

Latest revision as of 15:49, 9 November 2016

Rodriguez-Juarez F, Aguirre E, Cadenas S (2007) Relative sensitivity of soluble guanylate cyclase and mitochondrial respiration to endogenous nitric oxide at physiological oxygen concentration. Biochem J 405:223-31.

» PMID: 17441787 Open Access

Rodriguez-Juarez F, Aguirre E, Cadenas S (2007) Biochem J

Abstract: Disposition of the second messenger nitric oxide (NO) in mammalian tissues occurs through multiple pathways including dioxygenation by erythrocyte hemoglobin and red muscle myoglobin. Metabolism by a putative NO dioxygenase activity in non-striated tissues has also been postulated, but the exact nature of this activity is unknown. In the present study, we tested the hypothesis that cytoglobin, a newly discovered hexacoordinated globin, participates in cell-mediated NO consumption. Stable expression of small hairpin RNA targeting cytoglobin in fibroblasts resulted in decreased NO consumption and intracellular nitrate production. These cells were more sensitive to NO-induced inhibition of cell respiration and proliferation, which could be restored by re-expression of human cytoglobin. We also demonstrated cytoglobin expression in adventitial fibroblasts as well as vascular smooth muscle cells from various species including human and found that cytoglobin was expressed in the adventitia and media of intact rat aorta. These results indicate that cytoglobin contributes to cell-mediated NO dioxygenation and represents an important NO sink in the vascular wall.

• O2k-Network Lab: ES Madrid Cadenas S

Labels: MiParea: Respiration

Stress:Oxidative stress;RONS Organism: Rat Tissue;cell: Fibroblast Preparation: Intact cells

Regulation: Inhibitor, Oxygen kinetics Coupling state: ROUTINE

HRR: Oxygraph-2k

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 {{Publication
-|title=Rodriguez-Juarez F, Aguirre E, Cadenas S (2007) Relative sensitivity of soluble guanylate cyclase and mitochondrial respiration to endogenous nitric oxide at physiological oxygen concentration. Biochem. J. 405: 223-231.
+|title=Rodriguez-Juarez F, Aguirre E, Cadenas S (2007) Relative sensitivity of soluble guanylate cyclase and mitochondrial respiration to endogenous nitric oxide at physiological oxygen concentration. Biochem J 405:223-31.
+|info=[http://www.ncbi.nlm.nih.gov/pubmed/17441787 PMID: 17441787 Open Access]
 |authors=Rodriguez-Juarez F, Aguirre E, Cadenas S
 |year=2007
-|journal=Biochem. J.
+|journal=Biochem J
-|abstract=Nitric oxide (NO) is a widespread biological messenger that has many physiological and pathophysiological roles. Most of the physiological actions of NO are mediated through the activation of sGC (soluble guanylate cyclase) and the subsequent production of cGMP. NO also binds to the binuclear centre of COX (cytochrome c oxidase) and inhibits mitochondrial respiration in competition with oxygen and in a reversible manner. Although sGC is more sensitive to endogenous NO than COX at atmospheric oxygen tension, the more relevant question is which enzyme is more sensitive at physiological oxygen concentration. Using a system in which NO is generated inside the cells in a finely controlled manner, we determined cGMP accumulation by immunoassay and mitochondrial oxygen consumption by high-resolution respirometry at 30 µM oxygen. In the present paper, we report that the NO EC50 of sGC was approx. 2.9 nM, whereas that required to achieve IC50 of respiration was 141 nM (the basal oxygen consumption in the absence of NO was 14±0.8 pmol of O2/s per 106  cells). In accordance with this, the NO–cGMP signalling transduction pathway was activated at lower NO concentrations than the AMPKs (AMP-activated protein kinase) pathway. We conclude that sGC is approx. 50-fold more sensitive than cellular respiration to endogenous NO under our experimental conditions. The implications of these results for cell physiology are discussed.
+|abstract=Disposition of the second messenger nitric oxide (NO) in mammalian tissues occurs through multiple pathways including dioxygenation by erythrocyte hemoglobin and red muscle myoglobin. Metabolism by a putative NO dioxygenase activity in non-striated tissues has also been postulated, but the exact nature of this activity is unknown. In the present study, we tested the hypothesis that cytoglobin, a newly discovered hexacoordinated globin, participates in cell-mediated NO consumption. Stable expression of small hairpin RNA targeting cytoglobin in fibroblasts resulted in decreased NO consumption and intracellular nitrate production. These cells were more sensitive to NO-induced inhibition of cell respiration and proliferation, which could be restored by re-expression of human cytoglobin. We also demonstrated cytoglobin expression in adventitial fibroblasts as well as vascular smooth muscle cells from various species including human and found that cytoglobin was expressed in the adventitia and media of intact rat aorta. These results indicate that cytoglobin contributes to cell-mediated NO dioxygenation and represents an important NO sink in the vascular wall.
-|keywords=cytochrome c oxidase, high-resolution respirometry, mitochondrial respiration, nitric oxide (NO), oxygen consumption, soluble guanylate cyclase.
+|mipnetlab=ES Madrid Cadenas S
-|info=[http://www.ncbi.nlm.nih.gov/pubmed/17441787 PMID: 17441787]
+|discipline=Mitochondrial Physiology
 }}
 {{Labeling
+|area=Respiration
+|injuries=Oxidative stress;RONS
+|organism=Rat
+|tissues=Fibroblast
+|preparations=Intact cells
+|topics=Inhibitor, Oxygen kinetics
+|couplingstates=ROUTINE
 |instruments=Oxygraph-2k
-|topics=Respiration; OXPHOS; ETS Capacity
+|discipline=Mitochondrial Physiology
 }}