title: Metabolomics Analysis Reveals that AICAR Affects Glycerolipid, Ceramide and Nucleotide Synthesis Pathways in INS-1 Cells.
abstract: AMPK regulates many metabolic pathways including fatty acid and glucose metabolism, both of which are closely associated with insulin secretion in pancreatic β-cells. Insulin secretion is regulated by metabolic coupling factors such as ATP/ADP ratio and other metabolites generated by the metabolism of nutrients such as glucose, fatty acid and amino acids. However, the connection between AMPK activation and insulin secretion in β-cells has not yet been fully elucidated at a metabolic level. To study the effect of AMPK activation on glucose stimulated insulin secretion, we applied the pharmacological activator 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) to an INS-1 (832/13) β-cell line. We measured the change in 66 metabolites in the presence or absence of AICAR using different stable isotopic labeled nutrients to probe selected pathways. AMPK activation by AICAR increased basal insulin secretion and reduced the glucose stimulation index. Although ATP/ADP ratios were not strongly affected by AICAR, several other metabolites and pathways important for insulin secretion were affected by AICAR treatment including long-chain CoAs, malonyl-CoA, 3-hydroxy-3 methylglutaryl CoA, diacylglycerol, and farnesyl pyrophosphate. Tracer studies using 13C-glucose revealed lower glucose flux in the purine and pyrimidine pathway and in the glycerolipid synthesis pathway. Untargeted metabolomics revealed reduction in ceramides caused by AICAR that may explain the beneficial role of AMPK in protecting β-cells from lipotoxicity. Taken together, the results provide an overall picture of the metabolic changes associated with AICAR treatment and how it modulates insulin secretion and β-cell survival.
authors.affiliation: The Department of Chemistry, University of Michigan, Ann Arbor, United States of America; The Department of Internal Medicine, University of Michigan, Ann Arbor, United States of America.
authors.forename: Mahmoud A
authors.initials: MA
authors.lastname: ElAzzouny
authors.affiliation: The Department of Internal Medicine, University of Michigan, Ann Arbor, United States of America.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Evans
authors.affiliation: The Department of Internal Medicine, University of Michigan, Ann Arbor, United States of America.
authors.forename: Charles F
authors.initials: CF
authors.lastname: Burant
authors.affiliation: The Department of Chemistry, University of Michigan, Ann Arbor, United States of America; The Department of Pharmacology, University of Michigan, Ann Arbor, United States of America.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Kennedy
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D000214:Acyl Coenzyme A / Q000378:metabolism; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002247:Carbon Isotopes; D002460:Cell Line; D002518:Ceramides / Q000378:metabolism*; D004075:Diglycerides / Q000378:metabolism; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008316:Malonyl Coenzyme A / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000187:drug effects*; D055432:Metabolomics; D011106:Polyisoprenyl Phosphates / Q000378:metabolism; D051381:Rats; D012265:Ribonucleotides / Q000494:pharmacology*; D012717:Sesquiterpenes / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D000214:Acyl Coenzyme A; D002247:Carbon Isotopes; D002518:Ceramides; D004075:Diglycerides; D007004:Hypoglycemic Agents; D007328:Insulin; D011106:Polyisoprenyl Phosphates; D012265:Ribonucleotides; D012717:Sesquiterpenes; C008047:3-hydroxy-3-methylglutaryl-coenzyme A; D000620:Aminoimidazole Carboxamide; D008316:Malonyl Coenzyme A; C004808:farnesyl pyrophosphate; D055372:AMP-Activated Protein Kinases; C031143:AICA ribonucleotide; D005947:Glucose