Leptin is produced and secreted from islets of Langerhans, but the secretory dynamics and functions of leptin in this setting are unknown. The long-term goal is to quantitatively and simultaneously monitor secretion of peptides and proteins involved in the communication pathway between adipocytes and islets of Langerhans. The overall objective of this application is the development of technology to measure acute changes in leptin secretion from islets of Langerhans and determine how this secretion affects the release of traditional peptides. The central hypothesis is that islet-secreted leptin affects systemic glucose homeostasis by altering islet physiology. To test this hypothesis, the following aims will be accomplished: 1.) acute secretory dynamics of islet-secreted leptin will be determined using an immuno-PCR assay on a microfluidic device, 2.) the effect of leptin on islet physiology will be ascertained by simultaneously monitoring insulin, glucagon, and amylin secretion from islets of Langerhans on a microfluidic device using a multi-color electrophoretic immunoassay, and 3.) the effects that culture conditions have on islet-secreted leptin will be determined using a combination of the technology developed in aims 1 and 2. This work is significant as the role of islet-secreted leptin has not been defined and may identify a new mechanism that influences blood glucose levels. The methodology developed will also be applicable to other biological systems for measurement of simultaneous peptide or protein secretion. The function of islet-secreted leptin has not been investigated, but has the potential to impact broad areas of human health. The proposed research has relevance to public health because this knowledge will increase our understanding of islet biology and potentially provide new routes for alleviating complications associated with diabetes and obesity.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Project (R01)
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Enabling Bioanalytical and Biophysical Technologies Study Section (EBT)
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Appel, Michael C
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Florida State University
Schools of Arts and Sciences
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Yi, Lian; Wang, Xue; Dhumpa, Raghuram et al. (2015) Integrated perfusion and separation systems for entrainment of insulin secretion from islets of Langerhans. Lab Chip 15:823-32
Wang, Xue; Yi, Lian; Mukhitov, Nikita et al. (2015) Microfluidics-to-mass spectrometry: a review of coupling methods and applications. J Chromatogr A 1382:98-116
Wang, Xue; Roper, Michael G (2014) Measurement of DCF fluorescence as a measure of reactive oxygen species in murine islets of Langerhans. Anal Methods 6:3019-3024
Schrell, Adrian M; Roper, Michael G (2014) Frequency-encoded laser-induced fluorescence for multiplexed detection in infrared-mediated quantitative PCR. Analyst 139:2695-701
Dhumpa, Raghuram; Truong, Tuan M; Wang, Xue et al. (2014) Negative feedback synchronizes islets of Langerhans. Biophys J 106:2275-82
Mukhitov, Nikita; Yi, Lian; Schrell, Adrian M et al. (2014) Optimization of a microfluidic electrophoretic immunoassay using a Peltier cooler. J Chromatogr A 1367:154-60
Ren, Jianhua; Sherman, Arthur; Bertram, Richard et al. (2013) Slow oscillations of KATP conductance in mouse pancreatic islets provide support for electrical bursting driven by metabolic oscillations. Am J Physiol Endocrinol Metab 305:E805-17
Zhang, Xinyu; Dhumpa, Raghuram; Roper, Michael G (2013) Maintaining Stimulant Waveforms in Large Volume Microfluidic Cell Chambers. Microfluid Nanofluidics 15:
Lomasney, Anna R; Yi, Lian; Roper, Michael G (2013) Simultaneous monitoring of insulin and islet amyloid polypeptide secretion from islets of Langerhans on a microfluidic device. Anal Chem 85:7919-25
Yu, Yingjie; Li, Bowei; Baker, Christopher A et al. (2012) Quantitative polymerase chain reaction using infrared heating on a microfluidic chip. Anal Chem 84:2825-9

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