Tight coupling between glucose and mitochondrial metabolism in clonal beta-cells is required for robust insulin secretion.
Research output: Contribution to journal › Article
The biochemical mechanisms underlying glucose-stimulated insulin secretion from pancreatic beta-cells are not completely understood. To identify metabolic disturbances in beta-cells that impair glucose-stimulated insulin secretion, we compared two INS-1-derived clonal beta-cell lines, which are glucose-responsive (832/13) or glucose-unresponsive (832/2). We found that despite a marked impairment of glucose-stimulated insulin secretion, 832/2 cells exhibited a higher rate of glycolysis. Still, no glucose-induced increases in respiratory rate, ATP production or respiratory chain complex I, III and IV activities were seen in the 832/2 cells. Instead, 832/2 cells, which expressed lactate dehydrogenase, released lactate regardless of ambient glucose concentrations. In contrast, the glucose-responsive 832/13 line lacked lactate dehydrogenase and did not produce lactate. Accordingly, in 832/2 cells mRNA expression of genes for glycolytic enzymes were up-regulated, whereas mitochondria-related genes were down-regulated. In human islets, mRNA expression of genes such as lactate dehydrogenase A and hexokinase I correlated positively with long-term glucose homeostasis reflected by HbA1c levels, while that of Slc2a2 (GLUT2) correlated negatively with Hb1Ac. We conclude that tight metabolic regulation enhancing mitochondrial metabolism and restricting glycolysis in 832/13 cells is required for clonal beta-cells to secrete insulin robustly in response to glucose. Moreover, a similar expression pattern of genes controlling glycolytic and mitochondrial metabolism in clonal beta-cells and human islets was observed, suggesting that a similar prioritization of mitochondrial metabolism is required in healthy human beta-cells. The 832 beta-cell lines may be helpful tools to resolve metabolic perturbations occurring in Type 2 Diabetes.
|Research areas and keywords||
Subject classification (UKÄ) – MANDATORY
|Journal||Journal of Biological Chemistry|
|Publication status||Published - 2009|
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Neuronal Survival (013212041), Brain Repair and Imaging in Neural Systems (BRAINS) (013212027), Molecular Metabolism (013212001), Diabetes and Endocrinology (013241530), Molecular Metabolism (013244000)
Related research output
2012, Units of Epigenetics and Diabetes and Molecular Metabolism, Department of Clinical Sciences, Malmö. 162 p.
Research output: Thesis › Doctoral Thesis (compilation)