Glucotoxicity in Insulin-Producing β-Cells
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Background and aims: Type 2 diabetes mellitus is connected with elevated glucose levels, which cause impaired glucose-stimulated insulin secretion (GSIS) and degeneration of β-cells. Mechanisms for such glucotoxic effects were explored in the present study.
Materials and methods: INS-1E cells were cultured for 5 days in 5.5, 11, 20 or 27 mM glucose in the presence or absence of AMPK-agonist AICAR. GSIS was determined from INS-1E cells and islets obtained from type 2 diabetes and control donors. Human islets and INS-1E cells were functionally characterized (GSIS) and protein profiled (SELDI-TOF MS). Glucose-induced de novo synthesis of fatty acyls (HR-MAS NMR spectroscopy), fatty acid composition (GC-MS), triglyceride content and specific proteins (Western blotting) were determined in INS-1E cells.
Results: Impaired GSIS was observed from INS-1E cells exposed to chronic hyperglycaemia and islets isolated from type 2 diabetics compared to INS-1E cells cultured at normal glucose levels and control islets, respectively. Several glucose-regulated proteins were found when type 2 diabetes and control islets or mitochondria from INS-1E cells cultured at different glucose concentrations were protein profiled. Glucose induced lipid de novo synthesis of both saturated and unsaturated fatty acids in specific proportions. Glucose-induced impairment of function and mass was reverted by inclusion of AICAR, which lowered levels of pro-apoptotic protein CHOP but left triglyceride content unaffected.
Conclusions: Impaired GSIS and increased apoptosis observed in β-cells after prolonged exposure to elevated glucose concentrations involved accumulation of lipid species in specific proportions, AMPK-inactivation, ER-stress activation and complex, coordinated changes in expression patterns of mitochondrial and human islet proteins.
Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis , 2007. , 45 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 291
Cell biology, type 2 diabetes, SELDI-TOF MS, glucotoxicity, proteomics, insulin secretion, mitochondria, lipids, INS-1E cells, GC-MS, HR-MAS NMR, metabolomics, human islet, AMPK, AICAR, ER stress, apoptosis
IdentifiersURN: urn:nbn:se:uu:diva-8309ISBN: 978-91-554-7022-7OAI: oai:DiVA.org:uu-8309DiVA: diva2:171016
2007-12-08, B21, BMC, Husargatan 3, Uppsala, 09:15
Cnop, Miriam, Dr
Bergsten, Peter, DocentWelsh, Michael, Professor
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