title: Unspliced X-box-binding protein 1 (XBP1) protects endothelial cells from oxidative stress through interaction with histone deacetylase 3.
abstract: It is well known that atherosclerosis occurs geographically at branch points where disturbed flow predisposes to the development of plaque via triggering of oxidative stress and inflammatory reactions. In this study, we found that disturbed flow activated anti-oxidative reactions via up-regulating heme oxygenase 1 (HO-1) in an X-box-binding protein 1 (XBP1) and histone deacetylase 3 (HDAC3)-dependent manner. Disturbed flow concomitantly up-regulated the unspliced XBP1 (XBP1u) and HDAC3 in a VEGF receptor and PI3K/Akt-dependent manner. The presence of XBP1 was essential for the up-regulation of HDAC3 protein. Overexpression of XBP1u and/or HDAC3 activated Akt1 phosphorylation, Nrf2 protein stabilization and nuclear translocation, and HO-1 expression. Knockdown of XBP1u decreased the basal level and disturbed flow-induced Akt1 phosphorylation, Nrf2 stabilization, and HO-1 expression. Knockdown of HDAC3 ablated XBP1u-mediated effects. The mammalian target of rapamycin complex 2 (mTORC2) inhibitor, AZD2014, ablated XBP1u or HDAC3 or disturbed flow-mediated Akt1 phosphorylation, Nrf2 nuclear translocation, and HO-1 expression. Neither actinomycin D nor cycloheximide affected disturbed flow-induced up-regulation of Nrf2 protein. Knockdown of Nrf2 abolished XBP1u or HDAC3 or disturbed flow-induced HO-1 up-regulation. Co-immunoprecipitation assays demonstrated that XBP1u physically bound to HDAC3 and Akt1. The region of amino acids 201 to 323 of the HDAC3 protein was responsible for the binding to XBP1u. Double immunofluorescence staining revealed that the interactions between Akt1 and mTORC2, Akt1 and HDAC3, Akt1 and XBP1u, HDAC3, and XBP1u occurred in the cytosol. Thus, we demonstrate that XBP1u and HDAC3 exert a protective effect on disturbed flow-induced oxidative stress via up-regulation of mTORC2-dependent Akt1 phosphorylation and Nrf2-mediated HO-1 expression.
authors.affiliation: Cardiovascular Division, King's College London, London SE5 9NU, United Kingdom.
authors.forename: Daniel
authors.initials: D
authors.lastname: Martin
authors.affiliation: Cardiovascular Division, King's College London, London SE5 9NU, United Kingdom.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Cardiovascular Division, King's College London, London SE5 9NU, United Kingdom.
authors.forename: Junyao
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Emergency Medicine, the Second Affiliated Hospital, Xi'an Jiaotong University School of Medicine, Xi'an 710004, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.affiliation: Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Institute of Clinical Sciences, Belfast BT12 6BL, United Kingdom.
authors.forename: Andriana
authors.initials: A
authors.lastname: Margariti
authors.affiliation: Centre Laboratory, 305th Hospital of the People's Liberation Army, Beijing 100017, China, and.
authors.forename: Zhixin
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: Sino-German Laboratory for Molecular Medicine, Key Laboratory for Clinical Cardiovascular Genetics, Ministry of Education, FuWai Hospital, Chinese Academy of Medical Sciences, Beijing 100037, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Yu
authors.affiliation: Cardiovascular Division, King's College London, London SE5 9NU, United Kingdom.
authors.forename: Anna
authors.initials: A
authors.lastname: Zampetaki
authors.affiliation: Cardiovascular Division, King's College London, London SE5 9NU, United Kingdom.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Cardiovascular Division, King's College London, London SE5 9NU, United Kingdom,. Electronic address: qingbo.xu@kcl.ac.uk.
authors.forename: Qingbo
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Cardiovascular Division, King's College London, London SE5 9NU, United Kingdom,. Electronic address: lingfang.zeng@kcl.ac.uk.
authors.forename: Lingfang
authors.initials: L
authors.lastname: Zeng
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001158:Arteries / Q000473:pathology; D050197:Atherosclerosis / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000502:physiology*; D004730:Endothelium, Vascular / Q000473:pathology; D004789:Enzyme Activation; D051547:Heme Oxygenase-1 / Q000378:metabolism; D006655:Histone Deacetylases / Q000378:metabolism*; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism*; D006801:Humans; D000076225:Mechanistic Target of Rapamycin Complex 2; D018345:Mice, Knockout; D046912:Multiprotein Complexes / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D018384:Oxidative Stress; D010766:Phosphorylation; D011485:Protein Binding; D020033:Protein Isoforms / Q000502:physiology; D011499:Protein Processing, Post-Translational; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012039:Regional Blood Flow / Q000502:physiology; D000071701:Regulatory Factor X Transcription Factors; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D014157:Transcription Factors / Q000502:physiology*; D015854:Up-Regulation; D000071717:X-Box Binding Protein 1; D000099186:Histone Deacetylase 3
chemical_list: D004268:DNA-Binding Proteins; D051547:Heme Oxygenase-1; D006655:Histone Deacetylases; D000076225:Mechanistic Target of Rapamycin Complex 2; D046912:Multiprotein Complexes; D051267:NF-E2-Related Factor 2; D020033:Protein Isoforms; D051057:Proto-Oncogene Proteins c-akt; D000071701:Regulatory Factor X Transcription Factors; D058570:TOR Serine-Threonine Kinases; D014157:Transcription Factors; D000071717:X-Box Binding Protein 1; D000099186:Histone Deacetylase 3; C495635:NFE2L2 protein, human; C000605543:XBP1 protein, human; C000605544:Xbp1 protein, mouse; C496541:HMOX1 protein, human; C494918:AKT1 protein, human
keywords: Cell Signaling; Endothelial Cell; Histone Deacetylase (HDAC); Oxidative Stress; Shear Stress