title: Methotrexate promotes glucose uptake and lipid oxidation in skeletal muscle via AMPK activation.
abstract: Methotrexate (MTX) is a widely used anticancer and antirheumatic drug that has been postulated to protect against metabolic risk factors associated with type 2 diabetes, although the mechanism remains unknown. MTX inhibits 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/inosine monophosphate cyclohydrolase (ATIC) and thereby slows the metabolism of 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranosyl-5'-monophosphate (ZMP) and its precursor AICAR, which is a pharmacological AMPK activator. We explored whether MTX promotes AMPK activation in cultured myotubes and isolated skeletal muscle. We found MTX markedly reduced the threshold for AICAR-induced AMPK activation and potentiated glucose uptake and lipid oxidation. Gene silencing of the MTX target ATIC activated AMPK and stimulated lipid oxidation in cultured myotubes. Furthermore, MTX activated AMPK in wild-type HEK-293 cells. These effects were abolished in skeletal muscle lacking the muscle-specific, ZMP-sensitive AMPK-γ3 subunit and in HEK-293 cells expressing a ZMP-insensitive mutant AMPK-γ2 subunit. Collectively, our findings underscore a role for AMPK as a direct molecular link between MTX and energy metabolism in skeletal muscle. Cotherapy with AICAR and MTX could represent a novel strategy to treat metabolic disorders and overcome current limitations of AICAR monotherapy.
authors.affiliation: Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Sergej
authors.initials: S
authors.lastname: Pirkmajer
authors.affiliation: Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Sameer S
authors.initials: SS
authors.lastname: Kulkarni
authors.affiliation: Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Robby Z
authors.initials: RZ
authors.lastname: Tom
authors.affiliation: Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dundee, Scotland, U.K.
authors.forename: Fiona A
authors.initials: FA
authors.lastname: Ross
authors.affiliation: Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dundee, Scotland, U.K.
authors.forename: Simon A
authors.initials: SA
authors.lastname: Hawley
authors.affiliation: Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dundee, Scotland, U.K.
authors.forename: D Grahame
authors.initials: DG
authors.lastname: Hardie
authors.affiliation: Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden Department of Physiology and Pharmacology, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Juleen R
authors.initials: JR
authors.lastname: Zierath
authors.affiliation: Department of Molecular Medicine and Surgery, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden alexander.chibalin@ki.se.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Chibalin
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004789:Enzyme Activation / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D015227:Lipid Peroxidation; D008727:Methotrexate / Q000494:pharmacology*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism*; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D021122:Protein Subunits
chemical_list: D019384:Nucleic Acid Synthesis Inhibitors; D021122:Protein Subunits; D055372:AMP-Activated Protein Kinases; D005947:Glucose; D008727:Methotrexate