Hemoglobin α/eNOS coupling at myoendothelial junctions is required for nitric oxide scavenging during vasoconstriction.
Arterioscler Thromb Vasc Biol
; 34(12): 2594-600, 2014 Dec.
Article
em En
| MEDLINE
| ID: mdl-25278292
ABSTRACT
OBJECTIVE:
Hemoglobin α (Hb α) and endothelial nitric oxide synthase (eNOS) form a macromolecular complex at myoendothelial junctions; the functional role of this interaction remains undefined. To test if coupling of eNOS and Hb α regulates nitric oxide signaling, vascular reactivity, and blood pressure using a mimetic peptide of Hb α to disrupt this interaction. APPROACH ANDRESULTS:
In silico modeling of Hb α and eNOS identified a conserved sequence of interaction. By mutating portions of Hb α, we identified a specific sequence that binds eNOS. A mimetic peptide of the Hb α sequence (Hb α X) was generated to disrupt this complex. Using in vitro binding assays with purified Hb α and eNOS and ex vivo proximity ligation assays on resistance arteries, we have demonstrated that Hb α X significantly decreased interaction between eNOS and Hb α. Fluorescein isothiocyanate labeling of Hb α X revealed localization to holes in the internal elastic lamina (ie, myoendothelial junctions). To test the functional effects of Hb α X, we measured cyclic guanosine monophosphate and vascular reactivity. Our results reveal augmented cyclic guanosine monophosphate production and altered vasoconstriction with Hb α X. To test the in vivo effects of these peptides on blood pressure, normotensive and hypertensive mice were injected with Hb α X, which caused a significant decrease in blood pressure; injection of Hb α X into eNOS(-/-) mice had no effect.CONCLUSIONS:
These results identify a novel sequence on Hb α that is important for Hb α/eNOS complex formation and is critical for nitric oxide signaling at myoendothelial junctions.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vasoconstrição
/
Óxido Nítrico Sintase Tipo III
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Alfa-Globinas
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Óxido Nítrico
Limite:
Animals
/
Humans
/
Male
Idioma:
En
Revista:
Arterioscler Thromb Vasc Biol
Assunto da revista:
ANGIOLOGIA
Ano de publicação:
2014
Tipo de documento:
Article