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Signaling in Insulin-Secreting MIN6 Pseudoislets and Monolayer Cells
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Uppsala University, Science for Life Laboratory, SciLifeLab.
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2013 (English)In: Journal of Proteome Research, ISSN 1535-3893, E-ISSN 1535-3907, Vol. 12, no 12, 5954-5962 p.Article in journal (Refereed) Published
Abstract [en]

Cell cell interactions are of fundamental importance for cellular function. In islets of Langerhans, which control blood glucose levels by secreting insulin in response to the blood . glucose concentration, the secretory response of intact islets is c higher than that of insulin-producing beta-cells not arranged in the islet architecture. The objective was to define mechanisms by which cellular performance is enhanced when cells are arranged in a) three-dimensional space. The task was addressed by making a c comprehensive analysis based on protein expression patterns " generated from insulin-secreting MIN6 cells grown as islet-like c clusters, so-called pseudoislets, and in monolayers. After culture, glucose-stimulated insulin secretion (GSIS) was measured from monolayers and pseudoislets. GSIS rose 6-fold in pseudoislets but only 3-fold in monolayers when the glucose concentration was increased from 2 to 20 mmol/L. Proteins from pseudoislets and monolayers were extracted and analyzed by liquid-chromatography mass spectrometry, and differentially expressed proteins were mapped onto KEGG pathways. Protein profiling identified 1576 proteins, which were common to pseudoislets and monolayers. When mapped onto KEGG pathways, 11 highly enriched pathways were identified. On the basis of differences in expression of proteins belonging to the pathways in pseudoislets and monolayers, predictions of differential pathway activation were performed. Mechanisms enhancing insulin secretory capacity of the beta-cell, when situated in the islet, include pathways regulating glucose metabolism, cell interaction, and translational regulation.

Place, publisher, year, edition, pages
2013. Vol. 12, no 12, 5954-5962 p.
Keyword [en]
glucose-stimulated insulin secretion (GSIS), beta-cells, MIN6 cells, pseudoislets
National Category
Medical and Health Sciences
URN: urn:nbn:se:uu:diva-215288DOI: 10.1021/pr400864wISI: 000328231300053OAI: oai:DiVA.org:uu-215288DiVA: diva2:687037
Available from: 2014-01-13 Created: 2014-01-13 Last updated: 2015-01-23Bibliographically approved
In thesis
1. Role of Cell-cell Interactions and Palmitate on β-cells Function
Open this publication in new window or tab >>Role of Cell-cell Interactions and Palmitate on β-cells Function
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The islets of Langerhans secrets insulin in response to fluctuations of blood glucose level and efficient secretion requires extensive intra-islet communication. Secretory failure from islets is one of the hallmark in progression of type 2 diabetes.  Changes in islet structure and high levels of saturated free fatty acids may contribute to this failure. The aim of this thesis is to study the role of cell-cell interactions and palmitate on β-cells functions.

To address the role of cell-cell interactions on β-cells functions MIN6 cells were cultured as monolayers and as pseudoislets. Glucose stimulated insulin secretion was higher in pseudoislets compared to monolayers. Transcript levels of mitochondrial metabolism as well glucose oxidation rate was higher in pseudoislets. Insulin receptor substrate-1 (IRS-1) phosphorylation was altered when cells were grown as pseudoislets. Proteins expression levels related to glycolysis, cellular connections and translational regulations were up-regulated in pseudoislets. We propose the superior capacity of pseudoislets compared to monolayers depend on metabolism, cell coupling, gene translation, protein turnover and differential IRS-1 phosphorylation.

To address the role of palmitate on β-cells human islets were cultured in palmitate. Long term palmitate treatment decreased insulin secretion which is associated with up-regulation of suppressor of cytokine signaling-2 (SOCS2) and protein inhibitor of activated STAT-1 (PIAS1). Up-regulation of SOCS2 decreased phosphorylation of Akt at site T308, whereas PIAS1 decreased protein level of ATP- citrate lyase (ACLY) and ATP synthase subunit B (ATP5B). We propose long term palmitate treatment reduces phosphatidylinositol 3-kinase (PI3K) activity, attenuates formation of acetyl-CoA and decreases ATP synthesis which may aggravate β-cells dysfunction.  

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. 42 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 1025
Metabolism, PI3K, Pseudoislets, Human islets, SOCS, PIAS
National Category
Cell and Molecular Biology
Research subject
Biology with specialization in Molecular Biology
urn:nbn:se:uu:diva-230841 (URN)978-91-554-9021-8 (ISBN)
Public defence
2014-10-17, B41, BMC, Husargatan 3, Uppsala, 09:15 (English)
Available from: 2014-09-25 Created: 2014-08-30 Last updated: 2015-01-23

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Chowdhury, AzazulManukyan, LevonArtemenko, Konstantin A.Bergquist, JonasBergsten, Peter
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