TY - JOUR
T1 - In vivo monitoring of intracellular Ca2+ dynamics in the pancreatic β-cells of zebrafish embryos
AU - Lorincz, Reka
AU - Emfinger, Christopher H.
AU - Walcher, Andrea
AU - Giolai, Michael
AU - Krautgasser, Claudia
AU - Remedi, Maria S.
AU - Nichols, Colin G.
AU - Meyer, Dirk
N1 - Funding Information:
This project was supported by the Universität Innsbruck/ University of Innsbruck and a travel fellowship to R.L. by the Marshallplan-Jubiläumsstiftung/Austrian Marshall Plan Foundation.
Funding Information:
This project was supported by the Universit?t Innsbruck/University of Innsbruck and a travel fellowship to R.L. by the Marshallplan-Jubil?umsstiftung/Austrian Marshall Plan Foundation. We thank Robin Kimmel, Alexandra Koschak, Pidder Jansen-D?rr, Petronel Tuluc, Thorsten Schwerte for helpful discussions, Sonja T?chterle and Dzenana Tufegdzic for expert zebrafish care, and all members of the Molecular Biology Institute for technical assistance and advice.
Publisher Copyright:
© 2018, © 2018 The Authors. Published with license by Tayloy & Francis.
PY - 2018/11/2
Y1 - 2018/11/2
N2 - 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.
AB - 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.
KW - Cav1.2 channel
KW - GCaMP6s
KW - cacna1c
KW - early zebrafish development
KW - glucose-sensing of beta cells
KW - in vivo imaging
UR - http://www.scopus.com/inward/record.url?scp=85058147351&partnerID=8YFLogxK
U2 - 10.1080/19382014.2018.1540234
DO - 10.1080/19382014.2018.1540234
M3 - Article
C2 - 30521410
AN - SCOPUS:85058147351
SN - 1938-2014
VL - 10
SP - 221
EP - 238
JO - Islets
JF - Islets
IS - 6
ER -