title: PKCε-CREB-Nrf2 signalling induces HO-1 in the vascular endothelium and enhances resistance to inflammation and apoptosis.
abstract: OBJECTIVE
  Vascular injury leading to endothelial dysfunction is a characteristic feature of chronic renal disease, diabetes mellitus, and systemic inflammatory conditions, and predisposes to apoptosis and atherogenesis. Thus, endothelial dysfunction represents a potential therapeutic target for atherosclerosis prevention. The observation that activity of either protein kinase C epsilon (PKCε) or haem oxygenase-1 (HO-1) enhances endothelial cell (EC) resistance to inflammation and apoptosis led us to test the hypothesis that HO-1 is a downstream target of PKCε.
  
  
  RESULTS
  Expression of constitutively active PKCε in human EC significantly increased HO-1 mRNA and protein, whereas conversely aortas or cardiac EC from PKCε-deficient mice exhibited reduced HO-1 when compared with wild-type littermates. Angiotensin II activated PKCε and induced HO-1 via a PKCε-dependent pathway. PKCε activation significantly attenuated TNFα-induced intercellular adhesion molecule-1, and increased resistance to serum starvation-induced apoptosis. These responses were reversed by the HO antagonist zinc protoporphyrin IX. Phosphokinase antibody array analysis identified CREB1((Ser133)) phosphorylation as a PKCε signalling intermediary, and cAMP response element-binding protein 1 (CREB1) siRNA abrogated PKCε-induced HO-1 up-regulation. Likewise, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) was identified as a PKCε target using nuclear translocation and DNA-binding assays, and Nrf2 siRNA prevented PKCε-mediated HO-1 induction. Moreover, depletion of CREB1 inhibited PKCε-induced Nrf2 DNA binding, suggestive of transcriptional co-operation between CREB1 and Nrf2.
  
  
  CONCLUSIONS
  PKCε activity in the vascular endothelium regulates HO-1 via a pathway requiring CREB1 and Nrf2. Given the potent protective actions of HO-1, we propose that this mechanism is an important contributor to the emerging role of PKCε in the maintenance of endothelial homeostasis and resistance to injury.
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
authors.forename: Hayley
authors.initials: H
authors.lastname: Mylroie
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
authors.forename: Odile
authors.initials: O
authors.lastname: Dumont
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bauer
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
authors.forename: Clare C
authors.initials: CC
authors.lastname: Thornton
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
authors.forename: John
authors.initials: J
authors.lastname: Mackey
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
authors.forename: Damien
authors.initials: D
authors.lastname: Calay
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
authors.forename: Shahir S
authors.initials: SS
authors.lastname: Hamdulay
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
authors.forename: Joan R
authors.initials: JR
authors.lastname: Choo
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Boyle
authors.affiliation: The Cardiovascular Institute, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA.
authors.forename: Allen M
authors.initials: AM
authors.lastname: Samarel
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Randi
authors.affiliation: Department of Cardiovascular Sciences, University of Sheffield, Sheffield, UK.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Evans
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK justin.mason@imperial.ac.uk.
authors.forename: Justin C
authors.initials: JC
authors.lastname: Mason
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism*; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D004789:Enzyme Activation; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D051547:Heme Oxygenase-1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D006801:Humans; D007249:Inflammation / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D051744:Protein Kinase C-epsilon / Q000235:genetics / Q000378:metabolism*; D011524:Protoporphyrins / Q000494:pharmacology; D034622:RNA Interference; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: C115163:CREB1 protein, human; C492004:Creb1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; C495636:Nfe2l2 protein, mouse; D011524:Protoporphyrins; D000804:Angiotensin II; C017803:zinc protoporphyrin; C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1; C496542:Hmox1 protein, mouse; C497256:Prkce protein, mouse; C497255:PRKCE protein, human; D051744:Protein Kinase C-epsilon
keywords: Apoptosis; Endothelium; Haem oxygenase-1; Inflammation; Protein kinase C epsilon