Vascular Nox (NADPH oxidase) compartmentalization, protein hyperoxidation, and endoplasmic reticulum stress response in hypertension

De Lucca Camargo, L. et al. (2018) Vascular Nox (NADPH oxidase) compartmentalization, protein hyperoxidation, and endoplasmic reticulum stress response in hypertension. Hypertension, 72(1), pp. 235-246. (doi: 10.1161/HYPERTENSIONAHA.118.10824) (PMID:29844144) (PMCID:PMC6004120)

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Vascular Nox (NADPH oxidase)-derived reactive oxygen species and endoplasmic reticulum (ER) stress have been implicated in hypertension. However, relationships between these processes are unclear. We hypothesized that Nox isoforms localize in a subcellular compartment-specific manner, contributing to oxidative and ER stress, which influence the oxidative proteome and vascular function in hypertension. Nox compartmentalization (cell fractionation), O2− (lucigenin), H2O2 (amplex red), reversible protein oxidation (sulfenylation), irreversible protein oxidation (protein tyrosine phosphatase, peroxiredoxin oxidation), and ER stress (PERK [protein kinase RNA-like endoplasmic reticulum kinase], IRE1α [inositol-requiring enzyme 1], and phosphorylation/oxidation) were studied in spontaneously hypertensive rat (SHR) vascular smooth muscle cells (VSMCs). VSMC proliferation was measured by fluorescence-activated cell sorting, and vascular reactivity assessed in stroke-prone SHR arteries by myography. Noxs were downregulated by short interfering RNA and pharmacologically. In SHR, Noxs were localized in specific subcellular regions: Nox1 in plasma membrane and Nox4 in ER. In SHR, oxidative stress was associated with increased protein sulfenylation and hyperoxidation of protein tyrosine phosphatases and peroxiredoxins. Inhibition of Nox1 (NoxA1ds), Nox1/4 (GKT137831), and ER stress (4-phenylbutyric acid/tauroursodeoxycholic acid) normalized SHR vascular reactive oxygen species generation. GKT137831 reduced IRE1α sulfenylation and XBP1 (X-box binding protein 1) splicing in SHR. Increased VSMC proliferation in SHR was normalized by GKT137831, 4-phenylbutyric acid, and STF083010 (IRE1–XBP1 disruptor). Hypercontractility in the stroke-prone SHR was attenuated by 4-phenylbutyric acid. We demonstrate that protein hyperoxidation in hypertension is associated with oxidative and ER stress through upregulation of plasmalemmal-Nox1 and ER-Nox4. The IRE1–XBP1 pathway of the ER stress response is regulated by Nox4/reactive oxygen species and plays a role in the hyperproliferative VSMC phenotype in SHR. Our study highlights the importance of Nox subcellular compartmentalization and interplay between cytoplasmic reactive oxygen species and ER stress response, which contribute to the VSMC oxidative proteome and vascular dysfunction in hypertension

Item Type:Articles
Additional Information:This work was funded by grants from the British Heart Foundation (BHF; RG/13/7/30 099, RE/13/5/30 177) and the Medical Research Council (MC-PC-15 076). R.M. Touyz is supported through a BHF Chair award (CH/4/29 762). L.L. Camargo was supported by the Science Without Borders program (Proc 1815-14-8) and R.D.N.d.O. Silva was recipient of a Programa Nacional de Pós Doutorado fellowship (Proc 88 881.1321188/2016-01), both from Coordenação de Aperfeiçoamento de Pessoal de Nivel Superior, Brazil.
Glasgow Author(s) Enlighten ID:Harvey, Dr Adam and Graham, Dr Delyth and Cao, Dr Zhenbo and Tsiropoulou, Miss Sofia and Montezano, Dr Augusto and Bulleid, Professor Neil and McMaster, Dr Claire and Burchmore, Dr Richard and Hartley, Professor Richard and Touyz, Professor Rhian and Rios, Dr Francisco and De Lucca Camargo, Ms Livia
Authors: De Lucca Camargo, L., Harvey, A. P., Rios, F. J., Tsiropoulou, S., Silva, R. D. N. d. O., Cao, Z., Graham, D., McMaster, C., Burchmore, R. J., Hartley, R. C., Bulleid, N., Montezano, A. C., and Touyz, R. M.
College/School:College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
College of Medical Veterinary and Life Sciences > School of Infection & Immunity
College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
College of Science and Engineering > School of Chemistry
Journal Name:Hypertension
Publisher:American Heart Association
ISSN (Online):1524-4563
Published Online:29 May 2018
Copyright Holders:Copyright © 2018 The American Heart Association
First Published:First published in Hypertension 72(1):235-346
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
617771BHF centre of excellenceRhian TouyzBritish Heart Foundation (BHF)RE/13/5/30177RI CARDIOVASCULAR & MEDICAL SCIENCES