Imaging Cyclic AMP Changes in Pancreatic Islets of Transgenic Reporter Mice
Open Access
- 7 May 2008
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 3 (5), e2127
- https://doi.org/10.1371/journal.pone.0002127
Abstract
Cyclic AMP (cAMP) and Ca2+ are two ubiquitous second messengers in transduction pathways downstream of receptors for hormones, neurotransmitters and local signals. The availability of fluorescent Ca2+ reporter dyes that are easily introduced into cells and tissues has facilitated analysis of the dynamics and spatial patterns for Ca2+ signaling pathways. A similar dissection of the role of cAMP has lagged because indicator dyes do not exist. Genetically encoded reporters for cAMP are available but they must be introduced by transient transfection in cell culture, which limits their utility. We report here that we have produced a strain of transgenic mice in which an enhanced cAMP reporter is integrated in the genome and can be expressed in any targeted tissue and with tetracycline induction. We have expressed the cAMP reporter in β-cells of pancreatic islets and conducted an analysis of intracellular cAMP levels in relation to glucose stimulation, Ca2+ levels, and membrane depolarization. Pancreatic function in transgenic mice was normal. In induced transgenic islets, glucose evoked an increase in cAMP in β-cells in a dose-dependent manner. The cAMP response is independent of (in fact, precedes) the Ca2+ influx that results from glucose stimulation of islets. Glucose-evoked cAMP responses are synchronous in cells throughout the islet and occur in 2 phases suggestive of the time course of insulin secretion. Insofar as cAMP in islets is known to potentiate insulin secretion, the novel transgenic mouse model will for the first time permit detailed analyses of cAMP signals in β-cells within islets, i.e. in their native physiological context. Reporter expression in other tissues (such as the heart) where cAMP plays a critical regulatory role, will permit novel biomedical approaches.Keywords
This publication has 39 references indexed in Scilit:
- Requirement of Inositol Pyrophosphates for Full Exocytotic Capacity in Pancreatic β CellsScience, 2007
- Two cAMP‐dependent pathways differentially regulate exocytosis of large dense‐core and small vesicles in mouse β‐cellsThe Journal of Physiology, 2007
- Compartmentalization of protein kinase A signaling by the heterotrimeric G protein G oProceedings of the National Academy of Sciences of the United States of America, 2006
- Cell physiology of cAMP sensor EpacThe Journal of Physiology, 2006
- cAMP sensor Epac as a determinant of ATP‐sensitive potassium channel activity in human pancreatic β cells and rat INS‐1 cellsThe Journal of Physiology, 2006
- Insulin secretion in the conscious mouse is biphasic and pulsatileAmerican Journal of Physiology-Endocrinology and Metabolism, 2006
- Faithful Expression of GFP from the PLCβ2 Promoter in a Functional Class of Taste Receptor CellsChemical Senses, 2006
- Functional Fluorescent Ca2+ Indicator Proteins in Transgenic Mice under TET ControlPLoS Biology, 2004
- A variant of yellow fluorescent protein with fast and efficient maturation for cell-biological applicationsNature Biotechnology, 2002
- Nuclear translocation of the catalytic subunit of protein kinase A induced by an antisense oligonucleotide directed against the RIα regulatory subunitOncogene, 2001