scholarly journals Role of Carnitine Acetyl Transferase in Regulation of Nitric Oxide Signaling in Pulmonary Arterial Endothelial Cells

2012 ◽  
Vol 14 (1) ◽  
pp. 255-272 ◽  
Author(s):  
Shruti Sharma ◽  
Xutong Sun ◽  
Saurabh Agarwal ◽  
Ruslan Rafikov ◽  
Sridevi Dasarathy ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Nitric Oxide Signaling ◽  
Carnitine Acetyl Transferase ◽  
Pulmonary Arterial ◽  
Arterial Endothelial Cells

scholarly journals Shear stress stimulates nitric oxide signaling in pulmonary arterial endothelial cells via a reduction in catalase activity: role of protein kinase Cδ

2010 ◽  
Vol 298 (1) ◽  
pp. L105-L116 ◽  
Author(s):  
Sanjiv Kumar ◽  
Neetu Sud ◽  
Fabio V. Fonseca ◽  
Yali Hou ◽  
Stephen M. Black
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Catalase Activity ◽  
Serine Phosphorylation ◽  
Nitric Oxide Signaling ◽  
Enos Uncoupling ◽  
Pulmonary Arterial ◽  
Arterial Endothelial Cells

Previous studies have indicated that acute increases in shear stress can stimulate endothelial nitric oxide synthase (eNOS) activity through increased PI3 kinase/Akt signaling and phosphorylation of Ser1177. However, the mechanism by which shear stress activates this pathway has not been adequately resolved nor has the potential role of reactive oxygen species (ROS) been evaluated. Thus, the purpose of this study was to determine if shear-mediated increases in ROS play a role in stimulating Ser1177 phosphorylation and NO signaling in pulmonary arterial endothelial cells (PAEC) exposed to acute increases in shear stress. Our initial studies demonstrated that although shear stress did not increase superoxide levels in PAEC, there was an increase in H2O2 levels. The increases in H2O2 were associated with a decrease in catalase activity but not protein levels. In addition, we found that acute shear stress caused an increase in eNOS phosphorylation at Ser1177 phosphorylation and a decrease in phosphorylation at Thr495. We also found that the overexpression of catalase significantly attenuated the shear-mediated increases in H2O2, phospho-Ser1177 eNOS, and NO generation. Further investigation identified a decrease in PKCδ activity in response to shear stress, and the overexpression of PKCδ attenuated the shear-mediated decrease in Thr495 phosphorylation and the increase in NO generation, and this led to increased eNOS uncoupling. PKCδ overexpression also attenuated Ser1177 phosphorylation through a posttranslational increase in catalase activity, mediated via a serine phosphorylation event, reducing shear-mediated increases in H2O2. Together, our data indicate that shear stress decreases PKCδ activity, altering the phosphorylation pattern catalase, leading to decreased catalase activity and increased H2O2 signaling, and this in turn leads to increases in phosphorylation of eNOS at Ser1177 and NO generation.

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.

Matrix Stiffening Induces a Pathogenic QKI-miR-7-SRSF1 Signaling Axis in Pulmonary Arterial Endothelial Cells

2021 ◽  
Author(s):  
Chen-Shan Chen Woodcock ◽  
Neha Hafeez ◽  
Adam Handen ◽  
Ying Tang ◽  
Lloyd D Harvey ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Rna Binding ◽  
Vascular Diseases ◽  
Vascular Stiffness ◽  
Artery Stiffness ◽  
Signaling Axis ◽  
Pulmonary Arterial ◽  
Arterial Endothelial Cells ◽  
Splicing Factor 1

Pulmonary arterial hypertension (PAH) refers to a set of heterogeneous vascular diseases defined by elevation of pulmonary arterial pressure (PAP) and pulmonary vascular resistance (PVR), leading to right ventricular (RV) remodeling and often death. Early increases in pulmonary artery stiffness in PAH drive pathogenic alterations of pulmonary arterial endothelial cells (PAECs), leading to vascular remodeling. Dysregulation of microRNAs can drive PAEC dysfunction. However, the role of vascular stiffness in regulating pathogenic microRNAs in PAH is incompletely understood. Here, we demonstrated that extracellular matrix (ECM) stiffening downregulated miR-7 levels in PAECs. The RNA binding protein Quaking (QKI) has been implicated in the biogenesis of miR-7. Correspondingly, we found that ECM stiffness up-regulated QKI, and QKI knockdown led to increased miR-7. Downstream of the QKI-miR-7 axis, the serine and arginine rich splicing factor 1 (SRSF1) was identified as a direct target of miR-7. Correspondingly, SRSF1 was reciprocally up-regulated in PAECs exposed to stiff ECM and was negatively correlated with miR-7. Decreased miR-7 and increased QKI and SRSF1 were observed in lungs from PAH patients and PAH rats exposed to SU5416/hypoxia. Lastly, miR-7 upregulation inhibited human PAEC migration, while forced SRSF1 expression reversed this phenotype, proving that miR-7 depended upon SRSF1 to control migration. In aggregate, these results define the QKI-miR-7-SRSF1 axis as a mechanosensitive mechanism linking pulmonary arterial vascular stiffness to pathogenic endothelial function. These findings emphasize implications relevant to PAH and suggest the potential benefit of developing therapies that target this miRNA-dependent axis in PAH.

scholarly journals Golgi, trafficking, and mitosis dysfunctions in pulmonary arterial endothelial cells exposed to monocrotaline pyrrole and NO scavenging

2009 ◽  
Vol 297 (4) ◽  
pp. L715-L728 ◽  
Author(s):  
Jason Lee ◽  
Reuben Reich ◽  
Fang Xu ◽  
Pravin B. Sehgal
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Cell Surface ◽  
Live Cell ◽  
Cell Uptake ◽  
Important Distinction ◽  
No Donor ◽  
Pulmonary Arterial ◽  
Monocrotaline Pyrrole ◽  
Arterial Endothelial Cells

Although the administration of monocrotaline (MCT) into experimental animals is in widespread use today in investigations of pulmonary arterial hypertension (PAH), the underlying cellular and subcellular mechanisms that culminate in vascular remodeling are incompletely understood. Bovine pulmonary arterial endothelial cells (PAECs) in culture exposed to monocrotaline pyrrole (MCTP) develop “megalocytosis” 18–24 h later characterized by enlarged hyperploid cells with enlarged Golgi, mislocalization of endothelial nitric oxide synthase away from the plasma membrane, decreased cell-surface/caveolar nitric oxide (NO), and hypo- S-nitrosylation of caveolin-1, clathrin heavy chain, and N-ethylmaleimide-sensitive factor. We investigated whether MCTP did in fact affect functional intracellular trafficking. The NO scavenger (4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) and the NO donor diethylamine NONOate were used for comparison. Both MCTP and c-PTIO produced distinctive four- to fivefold enlarged PAECs within 24–48 h with markedly enlarged/dispersed Golgi, as visualized by immunostaining for the Golgi tethers/matrix proteins giantin, GM130, and p115. Live-cell uptake of the Golgi marker C5 ceramide revealed a compact juxtanuclear Golgi in untreated PAECs, brightly labeled enlarged circumnuclear Golgi after MCTP, but minimally labeled Golgi elements after c-PTIO. These Golgi changes were reduced by NONOate. After an initial inhibition during the first day, both MCTP and c-PTIO markedly enhanced anterograde secretion of soluble cargo (exogenous vector-expressed recombinant horseradish peroxidase) over the next 4 days. Live-cell internalization assays using fluorescently tagged ligands showed that both MCTP and c-PTIO inhibited the retrograde uptake of acetylated low-density lipoprotein, transferrin, and cholera toxin B. Moreover, MCTP, and to a variable extent c-PTIO, reduced the cell-surface density of all receptors assayed (LDLR, TfnR, BMPR, Tie-2, and PECAM-1/CD31). In an important distinction, c-PTIO enhanced mitosis in PAECs but MCTP inhibited mitosis, even that due to c-PTIO, despite markedly exaggerated Golgi dispersal. Taken together, these data define a broad-spectrum Golgi and subcellular trafficking dysfunction syndrome in endothelial cells exposed to MCTP or NO scavenging.

Alkalosis stimulates endothelial nitric oxide synthase in cultured human pulmonary arterial endothelial cells

2002 ◽  
Vol 283 (1) ◽  
pp. L113-L119 ◽  
Author(s):  
Shiro Mizuno ◽  
Yoshiki Demura ◽  
Shingo Ameshima ◽  
Seitaro Okamura ◽  
Isamu Miyamori ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Extracellular Ph ◽  
Enos Activity ◽  
Pulmonary Arterial ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Arterial Endothelial Cells

To investigate the effect of extracellular pH on endothelial nitric oxide synthase (eNOS) in human pulmonary arteries, we measured eNOS activity and expression as well as some ion channels in human pulmonary arterial endothelial cells (HPAEC) exposed to various pH levels (6.6–8.0). eNOS activity was found to increase with alkalization and decrease with acidification, while Ca2+ uptake into HPAEC increased with alkalization. The addition of 3′,4′-dichlorobenzamil hydrochloride, an inhibitor of the Na+/Ca2+ exchanger (NCX), prevented the increase of eNOS activity with alkalosis. Exposure to alkalosis and acidosis increased eNOS and NCX mRNA levels. These results suggest that an elevation of extracellular pH activates eNOS via the influx of extracellular Ca2+ and that NCX also regulates eNOS activity during alkalosis. Furthermore, NCX may have a tight interaction with eNOS at the level of transcription and might affect pulmonary circulation during alkalosis and acidosis.

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.

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