Investigation of the regulatory role of heme oxygenase-1 and its products during VEGF-induced angiogenesis, using in vitro and in vivo models
Angiogenesis is fundamental to many physiological processes, and associated with various pathologies, including atherosclerosis and malignant disease. Increasing evidence suggests a role for the cytoprotective enzyme heme oxygenase-1 (HO-1) and its products in angiogenesis. However, the mechanisms t...
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ndltd-bl.uk-oai-ethos.bl.uk-5723042017-06-27T03:23:31ZInvestigation of the regulatory role of heme oxygenase-1 and its products during VEGF-induced angiogenesis, using in vitro and in vivo modelsBauer, AndreaRandi, Anna ; Wait, Robin ; Mason, Justin2013Angiogenesis is fundamental to many physiological processes, and associated with various pathologies, including atherosclerosis and malignant disease. Increasing evidence suggests a role for the cytoprotective enzyme heme oxygenase-1 (HO-1) and its products in angiogenesis. However, the mechanisms through which HO-1 exerts its effects remain elusive. This study aims to identify signalling pathways and novel HO-1 downstream targets regulating angiogenesis. I show that inhibition of HO-1 with synthetic antagonist (ZnPP) or specific siRNA alters the angiogenic process at various levels. HO-1 inhibition significantly reduced vascular endothelial growth factor A (VEGF)-mediated human endothelial cell (EC) proliferation and inhibited capillary-like formation on 2D-Matrigel. Further, I demonstrate that VEGF-induced EC cell cycle progression is inhibited by HO-1 siRNA; an observation associated with decreased expression of cell cycle regulators cyclin A1 and cyclin E1. In contrast, HO-1-deficient cells were still protected from apoptosis by VEGF, most likely through induction of anti-apoptotic genes Bcl-2 and A1. Interestingly, HO-1 depletion negatively affected directional migration of EC towards a VEGF gradient; a phenotype reversed by HO-1 over-expression using an adenoviral vector. Moreover, migrating HO-1-deficient cells showed decreased cyclin A1 protein accompanied by decreased cyclin-dependent kinase 2 activity. Importantly, a combined proteomics and microarray approach has identified downstream targets of HO-1 and their potential roles in HO-1-driven angiogenesis have been investigated. For instance, HO-1 depletion results in impaired assembly of the intermediate filament vimentin. HO-1-deficient cells show reduced activity of the calcium-dependent protease calpain in response to VEGF; this observation was accompanied by a decrease in vimentin cleavage. The differences in vimentin cleavage and filament assembly may in turn account for the impaired angiogenic phenotype of HO-1-deficient cells. Identification of HO-1 downstream target genes may reveal potential therapeutic approaches for enhancing angiogenesis at sites of ischaemia or wound healing, or alternatively inhibiting angiogenesis associated with atherosclerosis or tumourogenesis.610Imperial College Londonhttp://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572304http://hdl.handle.net/10044/1/11159Electronic Thesis or Dissertation |
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610 Bauer, Andrea Investigation of the regulatory role of heme oxygenase-1 and its products during VEGF-induced angiogenesis, using in vitro and in vivo models |
description |
Angiogenesis is fundamental to many physiological processes, and associated with various pathologies, including atherosclerosis and malignant disease. Increasing evidence suggests a role for the cytoprotective enzyme heme oxygenase-1 (HO-1) and its products in angiogenesis. However, the mechanisms through which HO-1 exerts its effects remain elusive. This study aims to identify signalling pathways and novel HO-1 downstream targets regulating angiogenesis. I show that inhibition of HO-1 with synthetic antagonist (ZnPP) or specific siRNA alters the angiogenic process at various levels. HO-1 inhibition significantly reduced vascular endothelial growth factor A (VEGF)-mediated human endothelial cell (EC) proliferation and inhibited capillary-like formation on 2D-Matrigel. Further, I demonstrate that VEGF-induced EC cell cycle progression is inhibited by HO-1 siRNA; an observation associated with decreased expression of cell cycle regulators cyclin A1 and cyclin E1. In contrast, HO-1-deficient cells were still protected from apoptosis by VEGF, most likely through induction of anti-apoptotic genes Bcl-2 and A1. Interestingly, HO-1 depletion negatively affected directional migration of EC towards a VEGF gradient; a phenotype reversed by HO-1 over-expression using an adenoviral vector. Moreover, migrating HO-1-deficient cells showed decreased cyclin A1 protein accompanied by decreased cyclin-dependent kinase 2 activity. Importantly, a combined proteomics and microarray approach has identified downstream targets of HO-1 and their potential roles in HO-1-driven angiogenesis have been investigated. For instance, HO-1 depletion results in impaired assembly of the intermediate filament vimentin. HO-1-deficient cells show reduced activity of the calcium-dependent protease calpain in response to VEGF; this observation was accompanied by a decrease in vimentin cleavage. The differences in vimentin cleavage and filament assembly may in turn account for the impaired angiogenic phenotype of HO-1-deficient cells. Identification of HO-1 downstream target genes may reveal potential therapeutic approaches for enhancing angiogenesis at sites of ischaemia or wound healing, or alternatively inhibiting angiogenesis associated with atherosclerosis or tumourogenesis. |
author2 |
Randi, Anna ; Wait, Robin ; Mason, Justin |
author_facet |
Randi, Anna ; Wait, Robin ; Mason, Justin Bauer, Andrea |
author |
Bauer, Andrea |
author_sort |
Bauer, Andrea |
title |
Investigation of the regulatory role of heme oxygenase-1 and its products during VEGF-induced angiogenesis, using in vitro and in vivo models |
title_short |
Investigation of the regulatory role of heme oxygenase-1 and its products during VEGF-induced angiogenesis, using in vitro and in vivo models |
title_full |
Investigation of the regulatory role of heme oxygenase-1 and its products during VEGF-induced angiogenesis, using in vitro and in vivo models |
title_fullStr |
Investigation of the regulatory role of heme oxygenase-1 and its products during VEGF-induced angiogenesis, using in vitro and in vivo models |
title_full_unstemmed |
Investigation of the regulatory role of heme oxygenase-1 and its products during VEGF-induced angiogenesis, using in vitro and in vivo models |
title_sort |
investigation of the regulatory role of heme oxygenase-1 and its products during vegf-induced angiogenesis, using in vitro and in vivo models |
publisher |
Imperial College London |
publishDate |
2013 |
url |
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572304 |
work_keys_str_mv |
AT bauerandrea investigationoftheregulatoryroleofhemeoxygenase1anditsproductsduringvegfinducedangiogenesisusinginvitroandinvivomodels |
_version_ |
1718465458640781312 |