Internal pudendal artery dysfunction in diabetes is mediated by Nox1-derived Ros, NRF2- and RHO kinase-depedent mechanisms

Alves-Lopes, R., Neves, K. B., Montezano, A., Harvey, A., Carneiro, F. S., Touyz, R. and Tostes, R. C. (2016) Internal pudendal artery dysfunction in diabetes is mediated by Nox1-derived Ros, NRF2- and RHO kinase-depedent mechanisms. Hypertension, 68(4), pp. 1056-1064. (doi:10.1161/HYPERTENSIONAHA.116.07518) (PMID:27528061)

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Abstract

Oxidative stress plays an important role in diabetes mellitus (DM)–associated vascular injury. DM is an important risk factor for erectile dysfunction. Functional and structural changes in internal pudendal arteries (IPA) can lead to erectile dysfunction. We hypothesized that downregulation of nuclear factor E2–related factor 2 (Nrf2), consequent to increased nicotinamide adenine dinucleotide phosphate oxidase 1 (NOX1)-derived reactive oxygen species (ROS), impairs IPA function in DM. IPA and vascular smooth muscle cells from C57BL/6 (control) and NOX1 knockout mice were used. DM was induced by streptozotocin in C57BL/6 mice. Functional properties of IPA were assessed using a myograph, protein expression and peroxiredoxin oxidation by Western blot, RNA expression by polymerase chain reaction, carbonylation by oxyblot assay, ROS generation by lucigenin, nitrotyrosine, and amplex red, and Rho kinase activity and nuclear accumulation of Nrf2 by ELISA. IPA from diabetic mice displayed increased contractions to phenylephrine (control 138.5±9.5 versus DM 191.8±15.5). ROS scavenger, Nrf2 activator, NOX1 and Rho kinase inhibitors normalized vascular function. High glucose increased ROS generation in IPA vascular smooth muscle cell. This effect was abrogated by Nrf2 activation and not observed in NOX1 knockout vascular smooth muscle cell. High glucose also increased levels of nitrotyrosine, protein oxidation/carbonylation, and Rho kinase activity, but reduced Nrf2 activity and expression of Nrf2-regulated genes (catalase [25.6±0.05%], heme oxygenase-1 [21±0.1%], and NAD(P)H:quinone oxidoreductase 1 [22±0.1%]) and hydrogen peroxide levels. These effects were not observed in vascular smooth muscle cell from NOX1 knockout mice. In these cells, high glucose increased hydrogen peroxide levels. In conclusion, Rho kinase activation, via NOX1-derived ROS and downregulation of Nrf2 system, impairs IPA function in DM. These data suggest that Nrf2 is vasoprotective in DM-associated erectile dysfunction.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Harvey, Dr Adam and Montezano, Dr Augusto and Touyz, Professor Rhian
Authors: Alves-Lopes, R., Neves, K. B., Montezano, A., Harvey, A., Carneiro, F. S., Touyz, R., and Tostes, R. C.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
Journal Name:Hypertension
Publisher:American Heart Association
ISSN:0194-911X
ISSN (Online):1524-4563
Published Online:15 August 2016
Copyright Holders:Copyright © 2016 American Heart Association
First Published:First published in Hypertension 68(4):1056-1064
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
607382Vascular Noxs as therapeutic targets and biomarkers in hypertensionRhian TouyzBritish Heart Foundation (BHF)RG/13/7/30099RI CARDIOVASCULAR & MEDICAL SCIENCES