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Murine bone marrow-derived macrophages differentiated with GM-CSF become foam cells by PI3K?-dependent fluid-phase pinocytosis of native LDL

Anzinger, Joshua J. and Chang, Janet and Xu, Qing and Barthwal, Manoj K. and Bohnacker, Thomas and Wymann, Matthias P. and Kruth, Howard S.. (2012) Murine bone marrow-derived macrophages differentiated with GM-CSF become foam cells by PI3K?-dependent fluid-phase pinocytosis of native LDL. Journal of Lipid Research, 53 (1). pp. 34-42.

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Official URL: http://edoc.unibas.ch/dok/A6004143

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Abstract

Accumulation of cholesterol by macrophage uptake of LDL is a key event in the formation of atherosclerotic plaques. Previous research has shown that granulocyte-macrophage colony-stimulating factor (GM-CSF) is present in atherosclerotic plaques and promotes aortic lipid accumulation. However, it has not been determined whether murine GM-CSF-differentiated macrophages take up LDL to become foam cells. GM-CSF-differentiated macrophages from LDL receptor-null mice were incubated with LDL, resulting in massive macrophage cholesterol accumulation. Incubation of LDL receptor-null or wild-type macrophages with increasing concentrations of ¹²?I-LDL showed nonsaturable macrophage LDL uptake that was linearly related to the amount of LDL added, indicating that LDL uptake was mediated by fluid-phase pinocytosis. Previous studies suggest that phosphoinositide 3-kinases (PI3K) mediate macrophage fluid-phase pinocytosis, although the isoform mediating this process has not been determined. Because PI3K? is known to promote aortic lipid accumulation, we investigated its role in mediating macrophage fluid-phase pinocytosis of LDL. Wild-type macrophages incubated with LDL and the PI3K? inhibitor AS605240 or PI3K?-null macrophages incubated with LDL showed an ?50% reduction in LDL uptake and cholesterol accumulation compared with wild-type macrophages incubated with LDL only. These results show that GM-CSF-differentiated murine macrophages become foam cells by fluid-phase pinocytosis of LDL and identify PI3K? as contributing to this process.
Faculties and Departments:03 Faculty of Medicine > Departement Biomedizin > Division of Biochemistry and Genetics > Cancer- and Immunobiology (Wymann)
UniBasel Contributors:Wymann, Matthias P.
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:American Society for Biochemistry and Molecular Biology
ISSN:0022-2275
e-ISSN:1539-7262
Note:Publication type according to Uni Basel Research Database: Journal article
Language:English
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Last Modified:21 Nov 2017 13:21
Deposited On:26 Apr 2013 07:01

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