Cytokine treatment increases arginine metabolism and uptake in bovine pulmonary arterial endothelial cells

2001 ◽  
Vol 281 (5) ◽  
pp. L1232-L1239 ◽  
Author(s):  
Leif D. Nelin ◽  
Heather E. Nash ◽  
Louis G. Chicoine
Keyword(s):  
Endothelial Cells ◽  
Mrna Expression ◽  
Cationic Amino Acid ◽  
Cytokine Treatment ◽  
Nitrite Production ◽  
Urea Production ◽  
Pulmonary Arterial ◽  
Factor Α ◽  
Arterial Endothelial Cells ◽  
Necrosis Factor

l-Arginine (l-Arg) is metabolized to nitric oxide (NO) by NO synthase (NOS) or to urea by arginase (AR). l-Arg is transported into bovine pulmonary arterial endothelial cells (BPAECs) by cationic amino acid transporter-2 (CAT-2). We hypothesized that cytokine treatment would increase l-Arg metabolism and increase CAT-2 mRNA expression. BPAECs were incubated for 24 h in medium (control) or medium with lipopolysaccharide and tumor necrosis factor-α (L-T). L-T increased nitrite production (3.1 ± 0.4 nmol/24 h vs. 1.8 ± 0.1 nmol/24 h for control; P< 0.01) and urea production (83.5 ± 29.5 nmol/24 h vs. 17.8 ± 8.6 nmol/24 h for control; P < 0.05). L-T-treated BPAECs had greater endothelial and inducible NOS mRNA expression compared with control cells. Increasing the medium l-Arg concentration resulted in increased nitrite and urea production in both the control and the L-T-treated BPAECs. L-T treatment resulted in measurable CAT-2 mRNA. L-T increasedl-[3H]Arg uptake (5.78 ± 0.41 pmol vs. 4.45 ± 0.10 pmol for control; P < 0.05). In summary, L-T treatment increased l-Arg metabolism to both NO and urea in BPAECs and resulted in increased levels of CAT-2 mRNA. This suggests that induction of NOS and/or AR is linked to induction of CAT-2 in BPAECs and may represent a mechanism for maintainingl-Arg availability to NOS and/or AR.

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.

Gene transfer with inducible nitric oxide synthase decreases production of urea by arginase in pulmonary arterial endothelial cells

2006 ◽  
Vol 290 (2) ◽  
pp. L298-L306 ◽  
Author(s):  
Kate P. Stanley ◽  
Louis G. Chicoine ◽  
Tamara L. Young ◽  
Kristina M. Reber ◽  
C. Richard Lyons ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Gene Therapy ◽  
Endothelial Cells ◽  
Gene Transfer ◽  
No Production ◽  
Hypertensive Disorders ◽  
Inos Gene ◽  
Urea Production ◽  
Pulmonary Arterial ◽  
Arterial Endothelial Cells

Nitric oxide (NO) is a vasodilator produced from l-arginine (l-Arg) by NO synthase (NOS). Gene therapy for hypertensive disorders has been proposed using the inducible isoform of NOS (iNOS). l-Arg also can be metabolized to urea and l-ornithine (l-Orn) by arginase, and l-Orn can be metabolized to proline and/or polyamines, which are vital for cellular proliferation. To determine the effect of iNOS gene transfer on arginase, we transfected bovine pulmonary arterial endothelial cells (bPAEC) with an adenoviral vector containing the gene for iNOS (AdiNOS). As expected, NO production in AdiNOS bPAEC was substantially greater than in control bPAEC. Although urea production was significantly less in the AdiNOS bPAEC than in the control bPAEC, despite similar levels of arginase I protein, AdiNOS transfection of bPAEC had no effect on the uptake of l-Arg. Inhibiting NO production with Nω-nitro-l-arginine methyl ester increased urea production, and inhibiting urea production with l-valine increased nitrite production, in AdiNOS bPAEC. The addition of l-Arg to the medium increased urea production by AdiNOS bPAEC in a concentration-dependent manner. Thus, in these iNOS-transfected bPAEC, the transfected iNOS and native arginase compete for a common intracellular pool of l-Arg. This competition for substrate resulted in impaired proliferation in the AdiNOS-transfected bPAEC. These findings suggest that the use of iNOS gene therapy for pulmonary hypertensive disorders may not only be beneficial through NO-mediated pulmonary vasodilation but also may decrease vascular remodeling by limiting l-Orn production by native arginase.

Tumour necrosis factor-α gene expression and production in human umbilical arterial endothelial cells

2000 ◽  
Vol 98 (4) ◽  
pp. 461 ◽  
Author(s):  
Thomas NEUHAUS ◽  
Gudrun TOTZKE ◽  
Elisabeth GRUENEWALD ◽  
Hans-Peter JUESTEN ◽  
Agapios SACHINIDIS ◽  
...  
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Tumour Necrosis Factor Α ◽  
Factor Α ◽  
Arterial Endothelial Cells ◽  
Necrosis Factor

Tumour necrosis factor-α gene expression and production in human umbilical arterial endothelial cells

2000 ◽  
Vol 98 (4) ◽  
pp. 461-470 ◽  
Author(s):  
Thomas NEUHAUS ◽  
Gudrun TOTZKE ◽  
Elisabeth GRUENEWALD ◽  
Hans-Peter JUESTEN ◽  
Agapios SACHINIDIS ◽  
...  
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Dependent Manner ◽  
Tumour Necrosis Factor Α ◽  
Tnf Α ◽  
Factor Α ◽  
Arterial Endothelial Cells ◽  
Necrosis Factor

Endothelial cells act as an interface between the blood and tissues, and are known to be involved in inflammatory processes. These cells are responsive to and produce different cytokines. Tumour necrosis factor-α (TNF-α) not only is one of the most important inflammatory peptides, but also can be induced by lipopolysaccharide (LPS). The focus of the present study was on TNF-α gene expression and production in human umbilical arterial endothelial cells (HUAEC), including the kinetics of this process. Interleukin-1α (IL-1α), LPS and TNF-α, which are all known to be elevated in septic shock, were used as stimulators at concentrations commonly found in patients with sepsis. Through the use of reverse transcriptase/PCR, immunohistochemical reactions and ELISA techniques, we showed that, in HUAEC, all three stimuli were able to induce gene expression and production of TNF-α. Furthermore, this induction by IL-1α, LPS and TNF-α occurred in a time- and concentration-dependent manner in these cells. TNF-α expression and production was induced by all three agents at concentrations commonly found in patients with sepsis. TNF-α mRNA was observed within 30 min regardless of the stimulus used, but the levels peaked at different times. Since it is well established that TNF-α is able to induce the synthesis of IL-1α in endothelial cells and, as shown in the present study, TNF-α and IL-1α are themselves able to induce the synthesis of TNF-α in endothelial cells, an autocrine potentiation of cytokine release in sepsis can be proposed. This situation could lead to a locally acting ‘vicious cycle’ which, when considered in addition to the known ability of TNF-α to induce apoptosis, could mean that various organs will be damaged, a condition associated with sepsis. Thus these results provide further evidence for the important role played by the endothelium in inflammation.

Enalapril protects mice from pulmonary hypertension by inhibiting TNF-mediated activation of NF-κB and AP-1

2002 ◽  
Vol 282 (6) ◽  
pp. L1209-L1221 ◽  
Author(s):  
Luis A. Ortiz ◽  
Hunter C. Champion ◽  
Joseph A. Lasky ◽  
Federica Gambelli ◽  
Evelyn Gozal ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Lung Injury ◽  
Mrna Expression ◽  
Ace Inhibitor ◽  
Pulmonary Arterial ◽  
Factor Α ◽  
Deficient Mice ◽  
Enalapril Treatment ◽  
Necrosis Factor ◽  
Inhibitor Treatment

The present study was undertaken to investigate the effects of treatment with the angiotensin-converting enzyme (ACE) inhibitor enalapril in a mouse model of pulmonary hypertension induced by bleomycin. Bleomycin-induced lung injury in mice is mediated by enhanced tumor necrosis factor-α (TNF) expression in the lung, which determines the murine strain sensitivity to bleomycin, and murine strains are sensitive (C57BL/6) or resistant (BALB/c). Bleomycin induced significant pulmonary hypertension in C57BL/6, but not in BALB/c, mice; average pulmonary arterial pressure (PAP) was 26.4 ± 2.5 mmHg ( P < 0.05) vs. 15.2 ± 3 mmHg, respectively. Bleomycin treatment induced activation of nuclear factor (NF)-κB and activator protein (AP)-1 and enhanced collagen and TNF mRNA expression in the lung of C57BL/6 but not in BALB/c mice. Double TNF receptor-deficient mice (in a C57BL/6 background) that do not activate NF-κB or AP-1 in response to bleomycin did not develop bleomycin-induced pulmonary hypertension (PAP 14 ± 3 mmHg). Treatment of C57BL/6 mice with enalapril significantly ( P < 0.05) inhibited the development of pulmonary hypertension after bleomycin exposure. Enalapril treatment inhibited NF-κB and AP-1 activation, the enhanced TNF and collagen mRNA expression, and the deposition of collagen in bleomycin-exposed C57BL/6 mice. These results suggest that ACE inhibitor treatment decreases lung injury and the development of pulmonary hypertension in bleomycin-treated mice.

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