| First Author | Straub AC | Year | 2014 |
| Journal | Arterioscler Thromb Vasc Biol | Volume | 34 |
| Issue | 12 | Pages | 2594-600 |
| PubMed ID | 25278292 | Mgi Jnum | J:230469 |
| Mgi Id | MGI:5760115 | Doi | 10.1161/ATVBAHA.114.303974 |
| Citation | Straub AC, et al. (2014) Hemoglobin alpha/eNOS coupling at myoendothelial junctions is required for nitric oxide scavenging during vasoconstriction. Arterioscler Thromb Vasc Biol 34(12):2594-600 |
| abstractText | OBJECTIVE: Hemoglobin alpha (Hb alpha) 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 alpha regulates nitric oxide signaling, vascular reactivity, and blood pressure using a mimetic peptide of Hb alpha to disrupt this interaction. APPROACH AND RESULTS: In silico modeling of Hb alpha and eNOS identified a conserved sequence of interaction. By mutating portions of Hb alpha, we identified a specific sequence that binds eNOS. A mimetic peptide of the Hb alpha sequence (Hb alpha X) was generated to disrupt this complex. Using in vitro binding assays with purified Hb alpha and eNOS and ex vivo proximity ligation assays on resistance arteries, we have demonstrated that Hb alpha X significantly decreased interaction between eNOS and Hb alpha. Fluorescein isothiocyanate labeling of Hb alpha X revealed localization to holes in the internal elastic lamina (ie, myoendothelial junctions). To test the functional effects of Hb alpha X, we measured cyclic guanosine monophosphate and vascular reactivity. Our results reveal augmented cyclic guanosine monophosphate production and altered vasoconstriction with Hb alpha X. To test the in vivo effects of these peptides on blood pressure, normotensive and hypertensive mice were injected with Hb alpha X, which caused a significant decrease in blood pressure; injection of Hb alpha X into eNOS(-/-) mice had no effect. CONCLUSIONS: These results identify a novel sequence on Hb alpha that is important for Hb alpha/eNOS complex formation and is critical for nitric oxide signaling at myoendothelial junctions. |
