The pulsatility of glucose-dependent insulin secretion is disrupted in Type 2 diabetics (T2DM) and their first-degree relatives, and in animal models of the disease. Although dysfunctional electrical and calcium oscillations in beta cells likely contribute to insulin secretory deficits, the nature of this oscillatory dysfunction is not known;nor have the mechanisms underlying normal beta cell oscillations been fully elucidated. Research conducted during the previous period supports the hypothesis that oscillations in secretion result from complex interactions between electrical (EO) and metabolic oscillators (MO) intrinsic to islet beta cells (the 'Dual Oscillator Model';DOM). Pilot data obtained using a new experimental paradigm show that metabolic oscillations can dominate the electrical oscillator, have a distinctive time course unlike the predictions of other models, and can be decoupled from calcium. Building on this progress, we propose to: examine the properties of the EO and MO, elucidate how EO and MO interact to produce oscillations, and test the validity of the dual oscillator framework (Aim 1);investigate additional ionic mechanisms contributing to the DOM, including novel ion currents (Aim 2);determine whether islet metabolic oscillations are glycolytic or mitochondrial in origin, and design novel FRET probes and mass spectrometry approaches to measure intracellular fuel metabolites in living islets (Aim 3);and determine whether the dual oscillator accounts for the oscillatory properties of normal human islets or a mouse lacking KCNQ1, a putative beta cell potassium channel linked to T2DM;
Aim 4). Completion of these aims will represent the most comprehensive effort to date to understand the underlying oscillatory mechanisms of pancreatic islets, and will increase our insight into islet function in both health and disease.

Public Health Relevance

Patients with Type 2 diabetes secrete less insulin from their pancreatic islets and the pattern of this secretion is abnormal. Normal secretory patterns are required for proper insulin responses, but is poorly understood, we will systematically study the underlying mechanisms of these patterns at the cellular and subcellular levels using mouse and human islets. A better understanding of these processes may provide new ways to restore normal insulin secretion and reverse diabetes in these patients.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK046409-19
Application #
8265778
Study Section
Cellular Aspects of Diabetes and Obesity Study Section (CADO)
Program Officer
Appel, Michael C
Project Start
1993-12-01
Project End
2015-02-28
Budget Start
2012-03-01
Budget End
2013-02-28
Support Year
19
Fiscal Year
2012
Total Cost
$468,409
Indirect Cost
$163,385
Name
University of Michigan Ann Arbor
Department
Pharmacology
Type
Schools of Medicine
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Wedgwood, Kyle C A; Satin, Leslie S (2018) Six degrees of depolarization: Comment on ""Network science of biological systems at different scales: A review"" by Marko Gosak et al. Phys Life Rev 24:136-139
Bertram, Richard; Satin, Leslie S; Sherman, Arthur S (2018) Closing in on the Mechanisms of Pulsatile Insulin Secretion. Diabetes 67:351-359
Gregg, Brigid E; Botezatu, Nathalie; Brill, Joshua D et al. (2018) Gestational exposure to metformin programs improved glucose tolerance and insulin secretion in adult male mouse offspring. Sci Rep 8:5745
Yildirim, Vehpi; Vadrevu, Suryakiran; Thompson, Benjamin et al. (2017) Upregulation of an inward rectifying K+ channel can rescue slow Ca2+ oscillations in K(ATP) channel deficient pancreatic islets. PLoS Comput Biol 13:e1005686
Kim, So Yoon; Lee, Ji-Hyeon; Merrins, Matthew J et al. (2017) Loss of Cyclin-dependent Kinase 2 in the Pancreas Links Primary ?-Cell Dysfunction to Progressive Depletion of ?-Cell Mass and Diabetes. J Biol Chem 292:3841-3853
Satin, Leslie S; Parekh, Vishal S (2017) CFTR: Ferreting Out Its Role in Cystic Fibrosis-Related Diabetes. Endocrinology 158:3319-3321
Alejandro, Emilyn U; Bozadjieva, Nadejda; Blandino-Rosano, Manuel et al. (2017) Overexpression of Kinase-Dead mTOR Impairs Glucose Homeostasis by Regulating Insulin Secretion and Not ?-Cell Mass. Diabetes 66:2150-2162
Montemurro, Chiara; Vadrevu, Suryakiran; Gurlo, Tatyana et al. (2017) Cell cycle-related metabolism and mitochondrial dynamics in a replication-competent pancreatic beta-cell line. Cell Cycle 16:2086-2099
Satin, Leslie S; Ha, Joon; Sherman, Arthur S (2016) Islets Transplanted Into the Eye: Do They Improve Our Insight Into Islet Adaptation to Insulin Resistance? Diabetes 65:2470-2
Wynn, Michelle L; Yates, Joel A; Evans, Charles R et al. (2016) RhoC GTPase Is a Potent Regulator of Glutamine Metabolism and N-Acetylaspartate Production in Inflammatory Breast Cancer Cells. J Biol Chem 291:13715-29

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