scholarly journals Intracellular redox status and NAD(P)H:Quinone Oxidoreductase 1 (NQO1) activity in pulmonary arterial endothelial cells (PAEC)

2008 ◽  
Vol 22 (S1) ◽  
Author(s):  
Robert Bongard ◽  
Brian Lindemer ◽  
Marilyn Merker
Keyword(s):  
Endothelial Cells ◽  
Redox Status ◽  
Pulmonary Arterial ◽  
Arterial Endothelial Cells ◽  
Intracellular Redox Status ◽  
Intracellular Redox

Intracellular redox status affects transplasma membrane electron transport in pulmonary arterial endothelial cells

2002 ◽  
Vol 282 (1) ◽  
pp. L36-L43 ◽  
Author(s):  
Marilyn P. Merker ◽  
Robert D. Bongard ◽  
Nicholas J. Kettenhofen ◽  
Yoshiyuki Okamoto ◽  
Christopher A. Dawson
Keyword(s):  
Endothelial Cells ◽  
Electron Transport ◽  
Control Level ◽  
Redox Status ◽  
Cellular Mechanisms ◽  
Control Activity ◽  
Transplasma Membrane Electron Transport ◽  
Cell Extracts ◽  
Pulmonary Arterial ◽  
Arterial Endothelial Cells

Pulmonary arterial endothelial cells possess transplasma membrane electron transport (TPMET) systems that transfer intracellular reducing equivalents to extracellular electron acceptors. As one aspect of determining cellular mechanisms involved in one such TPMET system in pulmonary arterial endothelial cells in culture, glycolysis was inhibited by treatment with iodoacetate (IOA) or by replacing the glucose in the cell medium with 2-deoxy-d-glucose (2-DG). TPMET activity was measured as the rate of reduction of the extracellular electron acceptor polymer toluidine blue O polyacrylamide. Intracellular concentrations of NADH, NAD+, NADPH, and NADP+ were determined by high-performance liquid chromatography of KOH cell extracts. IOA decreased TPMET activity to 47% of control activity concomitant with a decrease in the NADH/NAD+ ratio to 34% of the control level, without a significant change in the NADPH/NADP+ ratio. 2-DG decreased TPMET activity to 53% of control and decreased both NADH/NAD+ and NADPH/NADP+ ratios to 51% and 55%, respectively, of control levels. When lactate was included in the medium along with the inhibitors, the effects of IOA and 2-DG on both TPMET activity and the NADPH/NADP+ ratios were prevented. The results suggest that cellular redox status is a determinant of pulmonary arterial endothelial cell TPMET activity, with TPMET activity more highly correlated with the poise of the NADH/NAD+redox pair.

scholarly journals Role of mitochondrial electron transport complex I in coenzyme Q1 reduction by intact pulmonary arterial endothelial cells and the effect of hyperoxia

2007 ◽  
Vol 293 (3) ◽  
pp. L809-L819 ◽  
Author(s):  
Marilyn P. Merker ◽  
Said H. Audi ◽  
Brian J. Lindemer ◽  
Gary S. Krenz ◽  
Robert D. Bongard
Keyword(s):  
Endothelial Cells ◽  
Electron Transport ◽  
Complex I ◽  
Coenzyme Q ◽  
Reduction Rate ◽  
Redox Status ◽  
Cell Protein ◽  
Pulmonary Arterial ◽  
Transport Complex ◽  
Arterial Endothelial Cells

The objective was to determine the impact of intact normoxic and hyperoxia-exposed (95% O2 for 48 h) bovine pulmonary arterial endothelial cells in culture on the redox status of the coenzyme Q10 homolog coenzyme Q1 (CoQ1). When CoQ1 (50 μM) was incubated with the cells for 30 min, its concentration in the medium decreased over time, reaching a lower level for normoxic than hyperoxia-exposed cells. The decreases in CoQ1 concentration were associated with generation of CoQ1 hydroquinone (CoQ1H2), wherein 3.4 times more CoQ1H2 was produced in the normoxic than hyperoxia-exposed cell medium (8.2 ± 0.3 and 2.4 ± 0.4 μM, means ± SE, respectively) after 30 min. The maximum CoQ1 reduction rate for the hyperoxia-exposed cells, measured using the cell membrane-impermeant redox indicator potassium ferricyanide, was about one-half that of normoxic cells (11.4 and 24.1 nmol·min−1·mg−1 cell protein, respectively). The mitochondrial electron transport complex I inhibitor rotenone decreased the CoQ1 reduction rate by 85% in the normoxic cells and 44% in the hyperoxia-exposed cells. There was little or no inhibitory effect of NAD(P)H:quinone oxidoreductase 1 (NQO1) inhibitors on CoQ1 reduction. Intact cell oxygen consumption rates and complex I activities in mitochondria-enriched fractions were also lower for hyperoxia-exposed than normoxic cells. The implication is that intact pulmonary endothelial cells influence the redox status of CoQ1 via complex I-mediated reduction to CoQ1H2, which appears in the extracellular medium, and that the hyperoxic exposure decreases the overall CoQ1 reduction capacity via a depression in complex I activity.

Influence of pulmonary arterial endothelial cells on quinone redox status: effect of hyperoxia-induced NAD(P)H:quinone oxidoreductase 1

2006 ◽  
Vol 290 (3) ◽  
pp. L607-L619 ◽  
Author(s):  
Marilyn P. Merker ◽  
Said H. Audi ◽  
Robert D. Bongard ◽  
Brian J. Lindemer ◽  
Gary S. Krenz
Keyword(s):  
Endothelial Cells ◽  
Reduction Rate ◽  
Total Activity ◽  
Redox Status ◽  
Complex Iii ◽  
Arterial Endothelial Cell ◽  
Pulmonary Arterial ◽  
The Difference ◽  
The Impact ◽  
Arterial Endothelial Cells

The objective of this study was to examine the impact of chronic hyperoxic exposure (95% O2for 48 h) on intact bovine pulmonary arterial endothelial cell redox metabolism of 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ). DQ or durohydroquinone (DQH2) was added to normoxic or hyperoxia-exposed cells in air-saturated medium, and the medium DQ concentrations were measured over 30 min. DQ disappeared from the medium when DQ was added and appeared in the medium when DQH2was added, such that after ∼15 min, a steady-state DQ concentration was approached that was ∼4.5 times lower for the hyperoxia-exposed than the normoxic cells. The rate of DQ-mediated reduction of the cell membrane-impermeant redox indicator, potassium ferricyanide [Fe(CN)[Formula: see text]], was also approximately twofold faster for the hyperoxia-exposed cells. Inhibitor studies and mathematical modeling suggested that in both normoxic and hyperoxia-exposed cells, NAD(P)H:quinone oxidoreductase 1 (NQO1) was the dominant DQ reductase and mitochondrial electron transport complex III the dominant DQH2oxidase involved and that the difference between the net effects of the cells on DQ redox status could be attributed primarily to a twofold increase in the maximum NQO1-mediated DQ reduction rate in the hyperoxia-exposed cells. Accordingly, NQO1 protein and total activity were higher in hyperoxia-exposed than normoxic cell cytosolic fractions. One outcome for hyperoxia-exposed cells was enhanced protection from cell-mediated DQ redox cycling. This study demonstrates that exposure to chronic hyperoxia increases the capacity of pulmonary arterial endothelial cells to reduce DQ to DQH2via a hyperoxia-induced increase in NQO1 protein and total activity.

Pulmonary arterial endothelial cells affect the redox status of coenzyme Q0

2003 ◽  
Vol 34 (7) ◽  
pp. 892-907 ◽  
Author(s):  
Said H. Audi ◽  
Hongtao Zhao ◽  
Robert D. Bongard ◽  
Neil Hogg ◽  
Nicholas J. Kettenhofen ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Redox Status ◽  
Pulmonary Arterial ◽  
Arterial Endothelial Cells ◽  
Coenzyme Q0

Impact of pulmonary arterial endothelial cells on duroquinone redox status

2004 ◽  
Vol 37 (1) ◽  
pp. 86-103 ◽  
Author(s):  
Marilyn P. Merker ◽  
Robert D. Bongard ◽  
Gary S. Krenz ◽  
Hongtao Zhao ◽  
Viola S. Fernandes ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Redox Status ◽  
Pulmonary Arterial ◽  
Arterial Endothelial Cells

Arginase inhibition increases nitric oxide production in bovine pulmonary arterial endothelial cells

2004 ◽  
Vol 287 (1) ◽  
pp. L60-L68 ◽  
Author(s):  
Louis G. Chicoine ◽  
Michael L. Paffett ◽  
Tamara L. Young ◽  
Leif D. Nelin
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
No Synthase ◽  
No Production ◽  
Urea Production ◽  
Pulmonary Arterial ◽  
Factor Α ◽  
Arterial Endothelial Cells ◽  
Regular Medium ◽  
Necrosis Factor

Nitric oxide (NO) is produced by NO synthase (NOS) from l-arginine (l-Arg). Alternatively, l-Arg can be metabolized by arginase to produce l-ornithine and urea. Arginase (AR) exists in two isoforms, ARI and ARII. We hypothesized that inhibiting AR with l-valine (l-Val) would increase NO production in bovine pulmonary arterial endothelial cells (bPAEC). bPAEC were grown to confluence in either regular medium (EGM; control) or EGM with lipopolysaccharide and tumor necrosis factor-α (L/T) added. Treatment of bPAEC with L/T resulted in greater ARI protein expression and ARII mRNA expression than in control bPAEC. Addition of l-Val to the medium led to a concentration-dependent decrease in urea production and a concentration-dependent increase in NO production in both control and L/T-treated bPAEC. In a second set of experiments, control and L/T bPAEC were grown in EGM, EGM with 30 mM l-Val, EGM with 10 mM l-Arg, or EGM with both 10 mM l-Arg and 30 mM l-Val. In both control and L/T bPAEC, treatment with l-Val decreased urea production and increased NO production. Treatment with l-Arg increased both urea and NO production. The addition of the combination l-Arg and l-Val decreased urea production compared with the addition of l-Arg alone and increased NO production compared with l-Val alone. These data suggest that competition for intracellular l-Arg by AR may be involved in the regulation of NOS activity in control bPAEC and in response to L/T treatment.

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