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Article: Deletion of Rap1 disrupts redox balance and impairs endothelium-dependent relaxations

TitleDeletion of Rap1 disrupts redox balance and impairs endothelium-dependent relaxations
Authors
KeywordsNitric oxide
Oxidative stress
Telomere
Vascular function
Issue Date2018
PublisherAcademic Press. The Journal's web site is located at http://www.elsevier.com/locate/yjmcc
Citation
Journal of Molecular and Cellular Cardiology, 2018, v. 115, p. 1-9 How to Cite?
AbstractAIMS: Repressor activator protein 1 (Rap1) is conventionally known as a static structural component of the telomere, but recent evidence indicates that it exerts functions within and outside the nucleus taking part in metabolic regulation and promoting inflammatory responses. The present study investigated whether or not Rap1 deletion affects oxidative stress and nitric oxide (NO) bioavailability in the vascular wall, thus modulating endothelial function. METHODS AND RESULTS: Vascular responsiveness was studied in wire myographs in aortae from Rap1 wildtype and knockout mice. Deletion of Rap1 impaired endothelium-dependent relaxations elicited by acetylcholine. Rap1 deficiency did not affect the activation of endothelial NO synthase or the sensitivity of vascular smooth muscle to NO donors. The blunted acetylcholine-mediated relaxations in Rap1 deficient aortae were restored with nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors, apocynin or VAS2870. Rap1 deletion lowered cellular thiol-redox status and diminished activities of thiol-redox enzymes, thioredoxin 1 and glutaredoxin 1. CONCLUSIONS: The capacity of thioredoxin 1 and glutaredoxin 1 to reduce intra-protein disulfide bridges is weakened in Rap1 deficient mice, resulting in hyper-activation of NADPH oxidase and greater reactive oxygen species generation. The high oxidative stress in Rap1 deficient mice is implicated with greater oxidative breakdown of NO, explaining the blunted acetylcholine-mediated relaxations in this animal. These findings imply that Rap1 plays an unanticipated role in regulating the fate of NO (a pivotal determinant of vascular homeostasis) and thus identify a new physiological importance of the telomere-associated protein.
Persistent Identifierhttp://hdl.handle.net/10722/258029
ISSN
2017 Impact Factor: 5.296
2015 SCImago Journal Rankings: 2.522
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorWong, HK-
dc.contributor.authorCai, Y-
dc.contributor.authorYing, F-
dc.contributor.authorChen, X-
dc.contributor.authorVanhoutte, PMGR-
dc.contributor.authorTang, EHC-
dc.date.accessioned2018-08-22T01:31:50Z-
dc.date.available2018-08-22T01:31:50Z-
dc.date.issued2018-
dc.identifier.citationJournal of Molecular and Cellular Cardiology, 2018, v. 115, p. 1-9-
dc.identifier.issn0022-2828-
dc.identifier.urihttp://hdl.handle.net/10722/258029-
dc.description.abstractAIMS: Repressor activator protein 1 (Rap1) is conventionally known as a static structural component of the telomere, but recent evidence indicates that it exerts functions within and outside the nucleus taking part in metabolic regulation and promoting inflammatory responses. The present study investigated whether or not Rap1 deletion affects oxidative stress and nitric oxide (NO) bioavailability in the vascular wall, thus modulating endothelial function. METHODS AND RESULTS: Vascular responsiveness was studied in wire myographs in aortae from Rap1 wildtype and knockout mice. Deletion of Rap1 impaired endothelium-dependent relaxations elicited by acetylcholine. Rap1 deficiency did not affect the activation of endothelial NO synthase or the sensitivity of vascular smooth muscle to NO donors. The blunted acetylcholine-mediated relaxations in Rap1 deficient aortae were restored with nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors, apocynin or VAS2870. Rap1 deletion lowered cellular thiol-redox status and diminished activities of thiol-redox enzymes, thioredoxin 1 and glutaredoxin 1. CONCLUSIONS: The capacity of thioredoxin 1 and glutaredoxin 1 to reduce intra-protein disulfide bridges is weakened in Rap1 deficient mice, resulting in hyper-activation of NADPH oxidase and greater reactive oxygen species generation. The high oxidative stress in Rap1 deficient mice is implicated with greater oxidative breakdown of NO, explaining the blunted acetylcholine-mediated relaxations in this animal. These findings imply that Rap1 plays an unanticipated role in regulating the fate of NO (a pivotal determinant of vascular homeostasis) and thus identify a new physiological importance of the telomere-associated protein.-
dc.languageeng-
dc.publisherAcademic Press. The Journal's web site is located at http://www.elsevier.com/locate/yjmcc-
dc.relation.ispartofJournal of Molecular and Cellular Cardiology-
dc.subjectNitric oxide-
dc.subjectOxidative stress-
dc.subjectTelomere-
dc.subjectVascular function-
dc.titleDeletion of Rap1 disrupts redox balance and impairs endothelium-dependent relaxations-
dc.typeArticle-
dc.identifier.emailCai, Y: caidavid@hku.hk-
dc.identifier.emailYing, F: sara130@hku.hk-
dc.identifier.emailVanhoutte, PMGR: vanhoutt@hku.hk-
dc.identifier.emailTang, EHC: evatang1@hku.hk-
dc.identifier.authorityVanhoutte, PMGR=rp00238-
dc.identifier.authorityTang, EHC=rp01382-
dc.identifier.doi10.1016/j.yjmcc.2017.12.009-
dc.identifier.pmid29277598-
dc.identifier.hkuros287565-
dc.identifier.volume115-
dc.identifier.spage1-
dc.identifier.epage9-
dc.identifier.isiWOS:000426620800001-
dc.publisher.placeUnited Kingdom-

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