ZFIN ID: ZDB-PUB-181207-28
In vivo monitoring of intracellular Ca2+ dynamics in the pancreatic β-cells of zebrafish embryos
Lorincz, R., Emfinger, C.H., Walcher, A., Giolai, M., Krautgasser, C., Remedi, M.S., Nichols, C.G., Meyer, D.
Date: 2018
Source: Islets   10(6): 221-238 (Journal)
Registered Authors: Krautgasser, Claudia, Lorincz, RĂ©ka, Meyer, Dirk
Keywords: Cav1.2 channel, GCaMP6s, cacna1c, early zebrafish development, glucose-sensing of beta cells, in vivo imaging
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • Calcium/metabolism*
  • Calcium Channels, L-Type/metabolism*
  • Embryo, Nonmammalian/metabolism*
  • Insulin-Secreting Cells/metabolism*
  • Zebrafish
PubMed: 30521410 Full text @ Islets
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ABSTRACT
Assessing the response of pancreatic islet cells to glucose stimulation is important for understanding β-cell function. Zebrafish are a promising model for studies of metabolism in general, including stimulus-secretion coupling in the pancreas. We used transgenic zebrafish embryos expressing a genetically-encoded Ca2+ sensor in pancreatic β-cells to monitor a key step in glucose induced insulin secretion; the elevations of intracellular [Ca2+]i. In vivo and ex vivo analyses of [Ca2+]i demonstrate that β-cell responsiveness to glucose is well established in late embryogenesis and that embryonic β-cells also respond to free fatty acid and amino acid challenges. In vivo imaging of whole embryos further shows that indirect glucose administration, for example by yolk injection, results in a slow and asynchronous induction of β-cell [Ca2+]i responses, while intravenous glucose injections cause immediate and islet-wide synchronized [Ca2+]i fluctuations. Finally, we demonstrate that embryos with disrupted mutation of the CaV1.2 channel gene cacna1c are hyperglycemic and that this phenotype is associated with glucose-independent [Ca2+]i fluctuation in β-cells. The data reveal a novel central role of cacna1c in β-cell specific stimulus-secretion coupling in zebrafish and demonstrate that the novel approach we propose - to monitor the [Ca2+]i dynamics in embryonic β-cells in vivo - will help to expand the understanding of β-cell physiological functions in healthy and diseased states.
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