Increased Expression of Endothelial and Neuronal Nitric Oxide Synthase In Dura and Pia Mater After Air Stress

Cephalalgia ◽  
2006 ◽  
Vol 26 (1) ◽  
pp. 14-25 ◽  
Author(s):  
T Zinck ◽  
R Illum ◽  
I Jansen-Olesen
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Protein Expression ◽  
Dura Mater ◽  
Underlying Mechanism ◽  
Pia Mater ◽  
Mrna And Protein Expression ◽  
Migraine Pathogenesis ◽  
Oxide Synthase

Stress is the leading precipitating factor for migraine attacks but the underlying mechanism is currently unknown. Nitric oxide (NO) has been implicated in migraine pathogenesis based on the ability of NO donors to induce migraine attacks. In the present study, we investigated in Wistar rats the effect of air stress on nitric oxide synthase (NOS) mRNA and protein expression in dura and pia mater using real-time polymerase chain reaction and Western blotting, respectively. Endothelial (e)NOS protein expression was significantly increased in dura and pia mater after air stress. Significantly augmented neuronal (n)NOS protein expression was detected in pia mater after air stress but not in dura mater. Inducible NOS mRNA and protein expression levels in dura and pia mater were unaffected by stress. The increased expression of eNOS in dura mater and eNOS and nNOS in pia mater seen after stress could not be antagonized by treatment with the migraine drug sumatriptan. These findings point towards the involvement of increased NO concentrations in dura and pia mater in response to air stress. However, the role of these findings in relation to migraine pathophysiology remains unclear.

Abstract 15396: Maintenance of Endothelial NO Release after Inhibition of NADPH Oxidase 4

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Claudia Eickholt ◽  
Coy Brunssen ◽  
Heike Langbein ◽  
Melanie Brux ◽  
Anja Hofmann ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Nitric Oxide Synthase ◽  
Nadph Oxidase ◽  
Protein Expression ◽  
Nadph Oxidase 4 ◽  
No Release ◽  
Mrna And Protein Expression ◽  
Oxide Synthase

The NADPH oxidase isoform NOX4 mainly produces H 2 O 2 . Previously we could show, that NOX4 is the major endothelial NOX isoform and constitutively active. Regulation of NOX4 and formation of reactive oxygen species are involved in NO release. The transcription factor NRF2 is a key mediator of cellular adaptation to redox stress. Therefore, regulation of NOX4 on the transcriptional level by NRF2 might be directly linked to NO release and endothelial function. Besides endothelial nitric oxide synthase (eNOS), a role of neuronal nitric oxide synthase (nNOS) in endothelial NO and H 2 O 2 release has been proposed. In this study, endothelial cells (HUVEC) were constantly exposed to high laminar shear stress (24 h, 30 dyn/cm 2 ). Application of shear stress stimulated NO formation and induced elongation of endothelial cells in the direction of flow. Lentiviral overexpression of NOX4 strongly increased endothelial H 2 O 2 release, while downregulation using shNOX4 decreased H 2 O 2 release. Furthermore, application of shear stress caused downregulation of NOX4 as well as upregulation of eNOS and antioxidative response via NRF2 and its target genes NQO-1 and HMOX-1. H 2 O 2 can affect NO release by eNOS. We could show that downregulation of NOX4 leads to upregulation of eNOS mRNA and protein expression accompanied by attenuation of NRF2 pathway under flow conditions. Determination of NO release confirmed these results. This supports a compensatory mechanism maintaining a stable NO release after NOX4 inhibition in response to flow. Attenuation of NRF2 by shNRF2 inhibited shear stress-dependent induction of NRF2 mRNA and protein expression and its target genes. In addition, shNRF2 enhanced the shear stress-dependent downregulation of NOX4. Finally, we detected a stable mRNA and protein expression of nNOS in endothelial cells, which was unaffected by flow. Interestingly, downregulation of NOX4 resulted in induction of nNOS expression. In conclusion, our data suggest an important role of H 2 O 2 production by NADPH oxidase 4 in maintaining NO release and endothelial function in response to flow. Inactivation of NADPH oxidase 4 attenuates NRF2 pathway and increases neuronal nitric oxide synthase as compensatory mechanisms.

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