title: Tetrahydrobiopterin and alkylglycerol monooxygenase substantially alter the murine macrophage lipidome.
abstract: Tetrahydrobiopterin is a cofactor synthesized from GTP with well-known roles in enzymatic nitric oxide synthesis and aromatic amino acid hydroxylation. It is used to treat mild forms of phenylketonuria. Less is known about the role of tetrahydrobiopterin in lipid metabolism, although it is essential for irreversible ether lipid cleavage by alkylglycerol monooxygenase. Here we found intracellular alkylglycerol monooxygenase activity to be an important regulator of alkylglycerol metabolism in intact murine RAW264.7 macrophage-like cells. Alkylglycerol monooxygenase was expressed and active also in primary mouse bone marrow-derived monocytes and "alternatively activated" M2 macrophages obtained by interleukin 4 treatment, but almost missing in M1 macrophages obtained by IFN-γ and lipopolysaccharide treatment. The cellular lipidome of RAW264.7 was markedly changed in a parallel way by modulation of alkylglycerol monooxygenase expression and of tetrahydrobiopterin biosynthesis affecting not only various ether lipid species upstream of alkylglycerol monooxygenase but also other more complex lipids including glycosylated ceramides and cardiolipins, which have no direct connection to ether lipid pathways. Alkylglycerol monooxygenase activity manipulation modulated the IFN-γ/lipopolysaccharide-induced expression of inducible nitric oxide synthase, interleukin-1β, and interleukin 1 receptor antagonist but not transforming growth factor β1, suggesting that alkylglycerol monooxygenase activity affects IFN-γ/lipopolysaccharide signaling. Our results demonstrate a central role of tetrahydrobiopterin and alkylglycerol monooxygenase in ether lipid metabolism of murine macrophages and reveal that alteration of alkylglycerol monooxygenase activity has a profound impact on the lipidome also beyond the class of ether lipids.
authors: Division of Biological Chemistry, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; katrin.watschinger@i-med.ac.at ernst.r.werner@i-med.ac.at.
authors: Katrin
authors: http://orcid.org/0000-0002-1122-8444
authors: K
authors: Watschinger
authors: Division of Biological Chemistry, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge CB2 1GA, United Kingdom;
authors: Markus A
authors: MA
authors: Keller
authors: Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom;
authors: Eileen
authors: E
authors: McNeill
authors: Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge CB2 1GA, United Kingdom;
authors: Mohammad T
authors: MT
authors: Alam
authors: Waters Corporation, Milford, MA 01757;
authors: Steven
authors: S
authors: Lai
authors: Division of Biological Chemistry, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
authors: Sabrina
authors: S
authors: Sailer
authors: Division of Molecular Pathophysiology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
authors: Veronika
authors: V
authors: Rauch
authors: Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom;
authors: Jyoti
authors: J
authors: Patel
authors: Institute of Biochemistry, Graz University of Technology, 8010 Graz, Austria;
authors: Albin
authors: A
authors: Hermetter
authors: Division of Biological Chemistry, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
authors: Georg
authors: G
authors: Golderer
authors: Division of Molecular Pathophysiology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
authors: Stephan
authors: S
authors: Geley
authors: Division of Biological Chemistry, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
authors: Gabriele
authors: G
authors: Werner-Felmayer
authors: Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom;
authors: Robert S
authors: RS
authors: Plumb
authors: Waters Corporation, Milford, MA 01757; Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC 20057-1468; and.
authors: Giuseppe
authors: G
authors: Astarita
authors: Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge CB2 1GA, United Kingdom; Medical Research Council National Institute for Medical Research, London NW7 1AA, United Kingdom.
authors: Markus
authors: M
authors: Ralser
authors: Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, United Kingdom;
authors: Keith M
authors: KM
authors: Channon
authors: Division of Biological Chemistry, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; katrin.watschinger@i-med.ac.at ernst.r.werner@i-med.ac.at.
authors: Ernst R
authors: ER
authors: Werner
mesh_terms: D000818:Animals; D001708:Biopterins / Q000031:analogs & derivatives* / Q000494:pharmacology; D001854:Bone Marrow Cells / Q000166:cytology; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D016000:Cluster Analysis; D006136:GTP Cyclohydrolase / Q000378:metabolism; D055785:Gene Knockdown Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D016086:Lentivirus / Q000378:metabolism; D050356:Lipid Metabolism / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D001708:Biopterins; D007371:Interferon-gamma; D006899:Mixed Function Oxygenases; D052247:Nitric Oxide Synthase Type II; C020678:glyceryl-ether monooxygenase; D006136:GTP Cyclohydrolase; C003402:sapropterin
keywords: RAW264.7; alkylglycerols; lipidomics; macrophages; tetrahydrobiopterin