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.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
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Cellular Aspects of Diabetes and Obesity Study Section (CADO)
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Appel, Michael C
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University of Michigan Ann Arbor
Schools of Medicine
Ann Arbor
United States
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Merrins, Matthew J; Poudel, Chetan; McKenna, Joseph P et al. (2016) Phase Analysis of Metabolic Oscillations and Membrane Potential in Pancreatic Islet β-Cells. Biophys J 110:691-9
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
Ha, Joon; Satin, Leslie S; Sherman, Arthur S (2016) A Mathematical Model of the Pathogenesis, Prevention, and Reversal of Type 2 Diabetes. Endocrinology 157:624-35
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
Glynn, Eric; Thompson, Benjamin; Vadrevu, Suryakiran et al. (2016) Chronic Glucose Exposure Systematically Shifts the Oscillatory Threshold of Mouse Islets: Experimental Evidence for an Early Intrinsic Mechanism of Compensation for Hyperglycemia. Endocrinology 157:611-23
McKenna, Joseph P; Ha, Joon; Merrins, Matthew J et al. (2016) Ca2+ Effects on ATP Production and Consumption Have Regulatory Roles on Oscillatory Islet Activity. Biophys J 110:733-42
Xu, Huanyu; Abuhatzira, Liron; Carmona, Gilberto N et al. (2015) The Ia-2β intronic miRNA, miR-153, is a negative regulator of insulin and dopamine secretion through its effect on the Cacna1c gene in mice. Diabetologia 58:2298-306
Alejandro, Emilyn U; Bozadjieva, Nadejda; Kumusoglu, Doga et al. (2015) Disruption of O-linked N-Acetylglucosamine Signaling Induces ER Stress and β Cell Failure. Cell Rep 13:2527-38
Satin, Leslie S; Schnell, Santiago (2015) Evidence for Residual and Partly Reparable Insulin Secretory Function and Maintained β-Cell Gene Expression in Islets From Patients With Type 1 Diabetes. Diabetes 64:2335-7
Satin, Leslie S; Butler, Peter C; Ha, Joon et al. (2015) Pulsatile insulin secretion, impaired glucose tolerance and type 2 diabetes. Mol Aspects Med 42:61-77

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