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Objective: Previous studies indicate a role for Oncostatin M (OSM) in atherosclerosis and other chronic inflammatory diseases for which inhibitory antibodies are in development. However, to date no intervention studies with OSM have been performed, and its relation to coronary heart disease (CHD) has not been studied., Approach and Results: Gene expression analysis on human normal arteries (n = 10) and late stage/advanced carotid atherosclerotic arteries (n = 127) and in situ hybridization on early human plaques (n = 9) showed that OSM, and its receptors, OSM receptor (OSMR) and Leukemia Inhibitory Factor Receptor (LIFR) are expressed in normal arteries and atherosclerotic plaques. Chronic OSM administration in APOE*3Leiden.CETP mice (n = 15/group) increased plasma E-selectin levels and monocyte adhesion to the activated endothelium independently of cholesterol but reduced the amount of inflammatory Ly-6CHigh monocytes and atherosclerotic lesion size and severity. Using aptamer-based proteomics profiling assays high circulating OSM levels were shown to correlate with post incident CHD survival probability in the AGES-Reykjavik study (n = 5457)., Conclusions: Chronic OSM administration in APOE*3Leiden.CETP mice reduced atherosclerosis development. In line, higher serum OSM levels were correlated with improved post incident CHD survival probability in patients, suggesting a protective cardiovascular effect., Competing Interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: Danielle van Keulen and Dennie Tempel are employed by Quorics B.V., Maarten D Sollewijn Gelpke by Molecular Profiling Consulting, Lori L Jennings by Novartis and Kim Holmstrøm and Boye Schnack Nielsen PhD by Bioneer A/S. There are no patents, products in development or marketed products to declare. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials,as detailed online in the guide for authors.

Aims: Endothelial activation is involved in many chronic inflammatory diseases, such as atherosclerosis, and is often initiated by cytokines. Oncostatin M (OSM) is a relatively unknown cytokine that has been suggested to play a role in both endothelial activation and atherosclerosis. We comprehensively investigated the effect of OSM on endothelial cell activation from different vascular beds and in APOE*3Leiden.CETP mice. Methods and results: Human umbilical vein endothelial cells, human aortic endothelial cells and human microvascular endothelial cells cultured in the presence of OSM express elevated MCP-1, IL-6 and ICAM-1 mRNA levels. Human umbilical vein endothelial cells and human aortic endothelial cells additionally expressed increased VCAM-1 and E-selectin mRNA levels. Moreover, ICAM-1 membrane expression is increased as well as MCP-1, IL-6 and E-selectin protein release. A marked increase was observed in STAT1 and STAT3 phosphorylation indicating that the JAK/STAT pathway is involved in OSM signaling. OSM signals through the LIF receptor alfa (LIFR) and the OSM receptor (OSMR). siRNA knockdown of the LIFR and the OSMR revealed that simultaneous knockdown is necessary to significantly reduce MCP-1 and IL-6 secretion, VCAM-1 and E-selectin shedding and STAT1 and STAT3 phosphorylation after OSM stimulation. Moreover, OSM administration to APOE*3Leiden.CETP mice enhances plasma E-selectin levels and increases ICAM-1 expression and monocyte adhesion in the aortic root area. Furthermore, Il-6 mRNA expression was elevated in the aorta of OSM treated mice. Conclusion: OSM induces endothelial activation in vitro in endothelial cells from different vascular beds through activation of the JAK/STAT cascade and in vivo in APOE*3Leiden.CETP mice. Since endothelial activation is an initial step in atherosclerosis development, OSM may play a role in the initiation of atherosclerotic lesion formation. [ABSTRACT FROM AUTHOR]

Abstract: Oxidized phospholipids (oxPL) have been found in atherosclerotic plaques and have been associated with the development of atherosclerosis. To investigate the LDL modifying effects of oxPL and subsequent consequences for macrophages, murine bone marrow macrophages were treated with LDL modified with the oxidation products of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine, oxPAPC. Effects of oxPAPC-modified LDL (oxPAPC-LDL) on macrophages were compared to native LDL, copper oxidized LDL (Cu-oxLDL) and acetylated LDL (acLDL). LDL treatment with oxPAPC or CuSO4 induced active oxidation of the LDL particles, resulting in significant increase in F2-isoprostanes, typical for LDL oxidation, compared with native LDL, acLDL or PAPC-LDL. Uptake of oxPAPC-LDL in macrophages was mediated by CD36 pathways as shown by SR-A and CD36 inhibitors. Surprisingly, both Cu-oxLDL and acLDL induced cholesterol ester accumulation in macrophages while oxPAPC-LDL did not. Microarray analysis showed a pronounced similarity between Cu-oxLDL and oxPAPC-LDL gene expression induction, whereas acLDL and oxPAPC-LDL did not overlap. The main feature shared by oxPAPC-LDL and Cu-oxLDL was the induction of the glutathione dependent antioxidant response, indicating an important role in protecting against both types of modified LDL induced stress. Our experiments show that oxPL modifies LDL, resulting in a minimally oxidized particle that shares many features of classically copper oxidized LDL and that may have relevant in vivo properties. [Copyright &y& Elsevier]

Objectives: We sought to examine the presence of hypoxia in human carotid atherosclerosis and its association with hypoxia-inducible transcription factor (HIF) and intraplaque angiogenesis. Background: Atherosclerotic plaques develop intraplaque angiogenesis, which is a typical feature of hypoxic tissue and expression of HIF. Methods: To examine the presence of hypoxia in atherosclerotic plaques, the hypoxia marker pimonidazole was infused before carotid endarterectomy in 7 symptomatic patients. Also, the messenger ribonucleic acid (mRNA) and protein expression of HIF1α, HIF2α, HIF-responsive genes (vascular endothelial growth factor [VEGF], glucose transporter [GLUT]1, GLUT3, hexokinase [HK]1, and HK2), and microvessel density were determined in a larger series of nondiseased and atherosclerotic carotid arteries with microarray, quantitative reverse transcription polymerase chain reaction, in situ hybridization, and immunohistochemistry. Results: Pimonidazole immunohistochemistry demonstrated the presence of hypoxia, especially within the macrophage-rich center of the lesions. Hypoxia correlated with the presence of a thrombus, angiogenesis, and expression of CD68, HIF, and VEGF. The mRNA and protein expression of HIF, its target genes, and microvessel density increased from early to stable lesions, but no changes were observed between stable and ruptured lesions. Conclusion: This is the first study directly demonstrating hypoxia in advanced human atherosclerosis and its correlation with the presence of macrophages and the expression of HIF and VEGF. Also, the HIF pathway was associated with lesion progression and angiogenesis, suggesting its involvement in the response to hypoxia and the regulation of human intraplaque angiogenesis. [Copyright &y& Elsevier]