title: Transcriptional Regulation of Cystathionine-γ-Lyase in Endothelial Cells by NADPH Oxidase 4-Dependent Signaling.
abstract: The gasotransmitter, hydrogen sulfide (H2S) is recognized as an important mediator of endothelial cell homeostasis and function that impacts upon vascular tone and blood pressure. Cystathionine-γ-lyase (CSE) is the predominant endothelial generator of H2S, and recent evidence suggests that its transcriptional expression is regulated by the reactive oxygen species, H2O2. However, the cellular source of H2O2 and the redox-dependent molecular signaling pathway that modulates this is not known. We aimed to investigate the role of Nox4, an endothelial generator of H2O2, in the regulation of CSE in endothelial cells. Both gain- and loss-of-function experiments in human endothelial cells in vitro demonstrated Nox4 to be a positive regulator of CSE transcription and protein expression. We demonstrate that this is dependent upon a heme-regulated inhibitor kinase/eIF2α/activating transcription factor 4 (ATF4) signaling module. ATF4 was further demonstrated to bind directly to cis-regulatory sequences within the first intron of CSE to activate transcription. Furthermore, CSE expression was also increased in cardiac microvascular endothelial cells, isolated from endothelial-specific Nox4 transgenic mice, compared with wild-type littermate controls. Using wire myography we demonstrate that endothelial-specific Nox4 transgenic mice exhibit a hypo-contractile phenotype in response to phenylephrine that was abolished when vessels were incubated with a CSE inhibitor, propargylglycine. We, therefore, conclude that Nox4 is a positive transcriptional regulator of CSE in endothelial cells and propose that it may in turn contribute to the regulation of vascular tone via the modulation of H2S production.
authors.affiliation: From the Cardiovascular Division, King's College London British Heart Foundation Centre, 125 Coldharbour Lane, London SE5 9NU and.
authors.forename: Rajesh K
authors.initials: RK
authors.lastname: Mistry
authors.affiliation: From the Cardiovascular Division, King's College London British Heart Foundation Centre, 125 Coldharbour Lane, London SE5 9NU and.
authors.forename: Thomas V A
authors.initials: TVA
authors.lastname: Murray
authors.affiliation: Cardiovascular Division, King's College London British Heart Foundation Centre, The Rayne Institute, St. Thomas' Hospital, London SE1 7EH, United Kingdom.
authors.forename: Oleksandra
authors.initials: O
authors.lastname: Prysyazhna
authors.affiliation: From the Cardiovascular Division, King's College London British Heart Foundation Centre, 125 Coldharbour Lane, London SE5 9NU and.
authors.forename: Daniel
authors.initials: D
authors.lastname: Martin
authors.affiliation: Cardiovascular Division, King's College London British Heart Foundation Centre, The Rayne Institute, St. Thomas' Hospital, London SE1 7EH, United Kingdom.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Burgoyne
authors.affiliation: From the Cardiovascular Division, King's College London British Heart Foundation Centre, 125 Coldharbour Lane, London SE5 9NU and.
authors.forename: Celio
authors.initials: C
authors.lastname: Santos
authors.affiliation: Cardiovascular Division, King's College London British Heart Foundation Centre, The Rayne Institute, St. Thomas' Hospital, London SE1 7EH, United Kingdom.
authors.forename: Philip
authors.initials: P
authors.lastname: Eaton
authors.affiliation: From the Cardiovascular Division, King's College London British Heart Foundation Centre, 125 Coldharbour Lane, London SE5 9NU and.
authors.forename: Ajay M
authors.initials: AM
authors.lastname: Shah
authors.affiliation: From the Cardiovascular Division, King's College London British Heart Foundation Centre, 125 Coldharbour Lane, London SE5 9NU and. Electronic address: alison.brewer@kcl.ac.uk.
authors.forename: Alison C
authors.initials: AC
authors.lastname: Brewer
mesh_terms: D051701:Activating Transcription Factor 4 / Q000235:genetics / Q000378:metabolism; D000818:Animals; D003542:Cystathionine gamma-Lyase / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D015971:Gene Expression Regulation, Enzymologic; D061307:Human Umbilical Vein Endothelial Cells / Q000201:enzymology*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014158:Transcription, Genetic
chemical_list: D051701:Activating Transcription Factor 4; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human; D003542:Cystathionine gamma-Lyase
keywords: ATF4; CSE; NADPH oxidase 4; endothelial cell; hydrogen sulfide; reactive oxygen species (ROS); redox signaling; transcription regulation; transgenic mice; vascular tone