title: Methotrexate-mediated activation of an AMPK-CREB-dependent pathway: a novel mechanism for vascular protection in chronic systemic inflammation.
abstract: OBJECTIVE
  Premature cardiovascular events complicate chronic inflammatory conditions. Low-dose weekly methotrexate (MTX), the most widely used disease-modifying drug for rheumatoid arthritis (RA), reduces disease-associated cardiovascular mortality. MTX increases intracellular accumulation of adenosine monophosphate (AMP) and 5-aminoimidazole-4-carboxamide ribonucleotide which activates AMP-activated protein kinase (AMPK). We hypothesised that MTX specifically protects the vascular endothelium against inflammatory injury via induction of AMPK-regulated protective genes.
  
  
  RESULTS
  In the (NZW×BXSB)F1 murine model of inflammatory vasculopathy, MTX 1 mg/kg/week significantly reduced intramyocardial vasculopathy and attenuated end-organ damage. Studies of human umbilical vein endothelial cells (HUVEC) and arterial endothelial cells (HAEC) showed that therapeutically relevant concentrations of MTX phosphorylate AMPKα(Thr172), and induce cytoprotective genes including manganese superoxide dismutase (MnSOD) and haem oxygenase-1 (HO-1). These responses were preserved when HUVECs were pretreated with tumour necrosis factor-α to mimic dysfunctional endothelium. Furthermore, MTX protected against glucose deprivation-induced endothelial apoptosis. Mechanistically, MTX treatment led to cyclic AMP response element-binding protein (CREB)(Ser133) phosphorylation, while AMPK depletion attenuated this response and the induction of MnSOD and HO-1. CREB siRNA inhibited upregulation of both cytoprotective genes by MTX, while chromatin immunoprecipitation demonstrated CREB binding to the MnSOD promoter in MTX-treated EC. Likewise, treatment of (NZW×BXSB)F1 mice with MTX enhanced AMPKα(Thr172) phosphorylation and MnSOD, and reduced aortic intercellular adhesion molecule-1 expression.
  
  
  CONCLUSIONS
  These data suggest that MTX therapeutically conditions vascular endothelium via activation of AMPK-CREB. We propose that this mechanism contributes to the protection against cardiovascular events seen in patients with RA treated with MTX.
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, London, UK.
authors.forename: C C
authors.initials: CC
authors.lastname: Thornton
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, London, UK King Fahad Cardiac Centre, King Saud University, Riyadh, Saudi Arabia.
authors.forename: F
authors.initials: F
authors.lastname: Al-Rashed
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, London, UK.
authors.forename: D
authors.initials: D
authors.lastname: Calay
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, London, UK.
authors.forename: G M
authors.initials: GM
authors.lastname: Birdsey
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Bauer
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, London, UK.
authors.forename: H
authors.initials: H
authors.lastname: Mylroie
authors.affiliation: University of Bath, Bath, UK.
authors.forename: B J
authors.initials: BJ
authors.lastname: Morley
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, London, UK.
authors.forename: A M
authors.initials: AM
authors.lastname: Randi
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, London, UK.
authors.forename: D O
authors.initials: DO
authors.lastname: Haskard
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, London, UK.
authors.forename: J J
authors.initials: JJ
authors.lastname: Boyle
authors.affiliation: Vascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, London, UK.
authors.forename: J C
authors.initials: JC
authors.lastname: Mason
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000818:Animals; D018501:Antirheumatic Agents / Q000494:pharmacology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D019877:Hydroxymethyl and Formyl Transferases / Q000378:metabolism; D007249:Inflammation; D008727:Methotrexate / Q000494:pharmacology*; D051379:Mice; D009097:Multienzyme Complexes / Q000378:metabolism; D009709:Nucleotide Deaminases / Q000378:metabolism; D010766:Phosphorylation; D056653:Rheumatoid Vasculitis / Q000188:drug therapy*; D015398:Signal Transduction / Q000187:drug effects*; D013482:Superoxide Dismutase / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha
chemical_list: D018501:Antirheumatic Agents; D017362:Cyclic AMP Response Element-Binding Protein; D009097:Multienzyme Complexes; D014409:Tumor Necrosis Factor-alpha; C113120:inosine monophosphate synthase; D051547:Heme Oxygenase-1; D013482:Superoxide Dismutase; D019877:Hydroxymethyl and Formyl Transferases; D055372:AMP-Activated Protein Kinases; D009709:Nucleotide Deaminases; D008727:Methotrexate
keywords: Atherosclerosis; Cardiovascular Disease; Inflammation; Methotrexate; Rheumatoid Arthritis