title: Investigation of salicylate hepatic responses in comparison with chemical analogues of the drug.
abstract: Anti-hyperglycaemic effects of the hydroxybenzoic acid salicylate might stem from effects of the drug on mitochondrial uncoupling, activation of AMP-activated protein kinase, and inhibition of NF-κB signalling. Here, we have gauged the contribution of these effects to control of hepatocyte glucose production, comparing salicylate with inactive hydroxybenzoic acid analogues of the drug. In rat H4IIE hepatoma cells, salicylate was the only drug tested that activated AMPK. Salicylate also reduced mTOR signalling, but this property was observed widely among the analogues. In a sub-panel of analogues, salicylate alone reduced promoter activity of the key gluconeogenic enzyme glucose 6-phosphatase and suppressed basal glucose production in mouse primary hepatocytes. Both salicylate and 2,6 dihydroxybenzoic acid suppressed TNFα-induced IκB degradation, and in genetic knockout experiments, we found that the effect of salicylate on IκB degradation was AMPK-independent. Previous data also identified AMPK-independent regulation of glucose but we found that direct inhibition of neither NF-κB nor mTOR signalling suppressed glucose production, suggesting that other factors besides these cell signalling pathways may need to be considered to account for this response to salicylate. We found, for example, that H4IIE cells were exquisitely sensitive to uncoupling with modest doses of salicylate, which occurred on a similar time course to another anti-hyperglycaemic uncoupling agent 2,4-dinitrophenol, while there was no discernible effect at all of two salicylate analogues which are not anti-hyperglycaemic. This finding supports much earlier literature suggesting that salicylates exert anti-hyperglycaemic effects at least in part through uncoupling.
authors.affiliation: Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland DD1 9SY, United Kingdom.
authors.forename: Amy R
authors.initials: AR
authors.lastname: Cameron
authors.affiliation: Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland DD1 9SY, United Kingdom.
authors.forename: Lisa
authors.initials: L
authors.lastname: Logie
authors.affiliation: Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland DD1 9SY, United Kingdom; MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, Scotland DD1 5EH, United Kingdom.
authors.forename: Kashyap
authors.initials: K
authors.lastname: Patel
authors.affiliation: Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland DD1 9SY, United Kingdom; James Hutton Institute, Invergowrie, Dundee, Scotland DD2 5DA, United Kingdom.
authors.forename: Sandra
authors.initials: S
authors.lastname: Bacon
authors.affiliation: Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland DD1 9SY, United Kingdom.
authors.forename: Calum
authors.initials: C
authors.lastname: Forteath
authors.affiliation: Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland DD1 9SY, United Kingdom.
authors.forename: Jean
authors.initials: J
authors.lastname: Harthill
authors.affiliation: Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland DD1 9SY, United Kingdom.
authors.forename: Adam
authors.initials: A
authors.lastname: Roberts
authors.affiliation: Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland DD1 9SY, United Kingdom.
authors.forename: Calum
authors.initials: C
authors.lastname: Sutherland
authors.affiliation: James Hutton Institute, Invergowrie, Dundee, Scotland DD2 5DA, United Kingdom; School of Life Sciences, Heriot-Watt University, Edinburgh, Scotland EH14 4AS, United Kingdom.
authors.forename: Derek
authors.initials: D
authors.lastname: Stewart
authors.affiliation: INSERM U1016, Institut Cochin, Paris 75014, France; CNRS UMR8104, Paris 75014, France; Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Viollet
authors.affiliation: MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, Scotland DD1 5EH, United Kingdom; Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Bâtiment G, 1015 Lausanne, Switzerland.
authors.forename: Kei
authors.initials: K
authors.lastname: Sakamoto
authors.affiliation: James Hutton Institute, Invergowrie, Dundee, Scotland DD2 5DA, United Kingdom.
authors.forename: Gordon
authors.initials: G
authors.lastname: McDougall
authors.affiliation: INSERM U1016, Institut Cochin, Paris 75014, France; CNRS UMR8104, Paris 75014, France; Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Foretz
authors.affiliation: Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland DD1 9SY, United Kingdom. Electronic address: g.rena@dundee.ac.uk.
authors.forename: Graham
authors.initials: G
authors.lastname: Rena
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D019298:Glucose-6-Phosphate / Q000378:metabolism; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D051381:Rats; D012459:Salicylates / Q000737:chemistry / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D016328:NF-kappa B; D012459:Salicylates; D019298:Glucose-6-Phosphate; C546842:MTOR protein, human; C546845:mTOR protein, rat; D058570:TOR Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases
keywords: AMPK; Gluconeogenesis; NF-κB signalling; Salicylate; mTOR signalling