1. Presence and regulation of insulin-regulated aminopeptidase in mouse macrophages
- Author
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Jo A. Van Ginderachter, Elio Schouppe, Huyen Thanh Thi Tran, Patrick Vanderheyden, Alexandros Nikolaou, Benoit Stijlemans, Siew Yeen Chai, Damya Laoui, Dirk Tourwé, Experimental Pharmacology, Molecular and Biochemical Pharmacology, Department of Bio-engineering Sciences, Cellular and Molecular Immunology, Faculty of Sciences and Bioengineering Sciences, Chemistry, Vriendenkring VUB, High Resolution NMR Centre, and Organic Chemistry
- Subjects
Lipopolysaccharides ,Medicine (General) ,mice ,Cell ,Intracellular Space ,Receptors, Cell Surface ,Biology ,Ligands ,Real-Time Polymerase Chain Reaction ,Proinflammatory cytokine ,PHAGOCYTOSIS ,Cell membrane ,Interferon-gamma ,Endocrinology ,R5-920 ,Western blot ,3T3-L1 Cells ,Internal Medicine ,medicine ,Animals ,Cystinyl Aminopeptidase ,Lectins, C-Type ,Macrophage activation ,RNA, Messenger ,glucose ,Mice, Knockout ,medicine.diagnostic_test ,Research Support, Non-U.S. Gov't ,Cell Membrane ,NF-kappa B ,Interleukin ,NFKB1 ,Molecular biology ,Mice, Inbred C57BL ,medicine.anatomical_structure ,Mannose-Binding Lectins ,Gene Expression Regulation ,inflammation ,Macrophages, Peritoneal ,Mannose Receptor ,Intracellular ,Transforming growth factor - Abstract
INTRODUCTION: The insulin-regulated aminopeptidase (IRAP) is expressed in several cell types, where it is mainly located in specialized secretory endosomes that are quickly recruited to the cell surface upon cell type-specific activation. Here we describe for the first time the expression and subcellular distribution of IRAP in macrophages. METHODS: IRAP mRNA expression, protein expression and presence at the cell surface was investigated by real-time polymerase chain reaction (PCR), Western blot and [(3)H]IVDE77 binding, respectively. RESULTS: IRAP mRNA expression was increased by interferon-γ (IFN-γ) and lipopolysaccharide (LPS), but not by anti-inflammatory cytokines (interleukin (IL)-4, IL-10, transforming growth factor β (TGF-β)). IFN-γ increased [(3)H]IVDE77 binding steadily over time, while LPS quickly and transiently recruited IRAP to the cell surface. Combined stimulations with IFN-γ and LPS showed the same pattern as LPS alone. Latex particles also induced a transient recruitment of IRAP to the cell surface, but no difference was observed in phagocytic uptake between wild-type and IRAP(-/-) macrophages, suggesting that the enzymatic activity of IRAP is not required for the ingestion of particles. CONCLUSION: IRAP is more highly expressed in pro-inflammatory M1-activated macrophages and its presence at the cell surface is modulated upon exposure to IFN-γ, LPS or exogenous particles.
- Published
- 2014