BACKGROUND: Macrophages are prominent in hypoxic areas of atherosclerotic lesions and their secreted cytokines, growth factors and activity of enzymes are involved in atherogenesis. Previously, we showed that 15-lipoxygenase (LOX)-2 is expressed in human monocyte-derived macrophages and that hypoxia increases 15-LOX-2 expression and secretion of pro-inflammatory molecules. Here we investigated whether human carotid plaque macrophages express 15-LOX-2 and whether its expression in macrophages is regulated by hypoxia through hypoxia-inducible factor 1alpha (HIF-1alpha). MATERIALS AND METHODS: Carotid plaques from 47 patients with high-grade symptomatic carotid artery stenosis were analysed using immunohistochemistry, and stained areas were quantified by digital image analysis. Carotid plaque macrophages were isolated with anti-CD14 immunobeads using an immunomagnetic bead technique. Primary macrophages were transfected with HIF-1alpha siRNA or control siRNA before extraction of RNA and medium analysis. RESULTS: In paired tissue sections, the extent of staining for CD68 correlated with staining for 15-LOX-2 but not for 15-LOX-1. In carotid plaque macrophages isolated with anti-CD14 immunobeads, 15-LOX-2 mRNA was expressed at high levels. In primary macrophages, 15-LOX-2 expression was significantly increased by incubation with the HIF-1alpha stabilizer dimethyloxalylglycine. Knockdown of HIF-1alpha significantly decreased production of the 15-LOX-2 enzyme products 12- and 15-hydroxyeicosatetraenoic acid. In carotid plaques, HIF-1alpha staining correlated with staining for 15-LOX-2. CONCLUSIONS: These results demonstrate that 15-LOX-2 is highly expressed in human plaques and is correlated with the presence of macrophages and HIF-1alpha. 15-LOX-2 enzyme activity can be modulated by HIF-1alpha. Thus, increased expression of 15-LOX-2 in macrophages in hypoxic atherosclerotic plaque may enhance inflammation and the recruitment of inflammatory cells.
BACKGROUND: Macrophages are prominent in hypoxic areas of atherosclerotic lesions and their secreted cytokines, growth factors and activity of enzymes are involved in atherogenesis. Previously, we showed that 15-lipoxygenase (LOX)-2 is expressed in human monocyte-derived macrophages and that hypoxia increases15-LOX-2 expression and secretion of pro-inflammatory molecules. Here we investigated whether human carotid plaque macrophages express 15-LOX-2 and whether its expression in macrophages is regulated by hypoxia through hypoxia-inducible factor 1alpha (HIF-1alpha). MATERIALS AND METHODS: Carotid plaques from 47 patients with high-grade symptomatic carotid artery stenosis were analysed using immunohistochemistry, and stained areas were quantified by digital image analysis. Carotid plaque macrophages were isolated with anti-CD14 immunobeads using an immunomagnetic bead technique. Primary macrophages were transfected with HIF-1alpha siRNA or control siRNA before extraction of RNA and medium analysis. RESULTS: In paired tissue sections, the extent of staining for CD68 correlated with staining for 15-LOX-2 but not for 15-LOX-1. In carotid plaque macrophages isolated with anti-CD14 immunobeads, 15-LOX-2 mRNA was expressed at high levels. In primary macrophages, 15-LOX-2 expression was significantly increased by incubation with the HIF-1alpha stabilizer dimethyloxalylglycine. Knockdown of HIF-1alpha significantly decreased production of the 15-LOX-2 enzyme products 12- and 15-hydroxyeicosatetraenoic acid. In carotid plaques, HIF-1alpha staining correlated with staining for 15-LOX-2. CONCLUSIONS: These results demonstrate that 15-LOX-2 is highly expressed in human plaques and is correlated with the presence of macrophages and HIF-1alpha. 15-LOX-2 enzyme activity can be modulated by HIF-1alpha. Thus, increased expression of 15-LOX-2 in macrophages in hypoxic atherosclerotic plaque may enhance inflammation and the recruitment of inflammatory cells.
Authors: Anca D Dobrian; David C Lieb; Banumathi K Cole; David A Taylor-Fishwick; Swarup K Chakrabarti; Jerry L Nadler Journal: Prog Lipid Res Date: 2010-10-21 Impact factor: 16.195
Authors: Pontus Boström; Nina Mann; Jun Wu; Pablo A Quintero; Eva R Plovie; Daniela Panáková; Rana K Gupta; Chunyang Xiao; Calum A MacRae; Anthony Rosenzweig; Bruce M Spiegelman Journal: Cell Date: 2010-12-23 Impact factor: 41.582
Authors: Anca D Dobrian; David C Lieb; Qian Ma; John W Lindsay; Banumathi K Cole; Kaiwen Ma; Swarup K Chakrabarti; Norine S Kuhn; Stephen D Wohlgemuth; Mark Fontana; Jerry L Nadler Journal: Biochem Biophys Res Commun Date: 2010-11-19 Impact factor: 3.575
Authors: Steven C Perry; Chakrapani Kalyanaraman; Benjamin E Tourdot; William S Conrad; Oluwayomi Akinkugbe; John Cody Freedman; Michael Holinstat; Matthew P Jacobson; Theodore R Holman Journal: J Lipid Res Date: 2020-05-13 Impact factor: 5.922
Authors: Karan Agrawal; Eleni Melliou; Xueqi Li; Theresa L Pedersen; Selina C Wang; Prokopios Magiatis; John W Newman; Roberta R Holt Journal: J Funct Foods Date: 2017-07-03 Impact factor: 4.451
Authors: Abigail R Green; Shannon Barbour; Thomas Horn; Jose Carlos; Jevgenij A Raskatov; Theodore R Holman Journal: Biochemistry Date: 2016-05-13 Impact factor: 3.162
Authors: Matthew J Kobe; David B Neau; Caitlin E Mitchell; Sue G Bartlett; Marcia E Newcomer Journal: J Biol Chem Date: 2014-02-04 Impact factor: 5.157