AIMS/HYPOTHESIS: Following on from the emerging importance of the pancreas circadian clock on islet function and the development of type 2 diabetes in rodent models, we aimed to examine circadian gene expression in human islets. The oscillator properties were assessed in intact islets as well as in beta cells. METHODS: We established a system for long-term bioluminescence recording in cultured human islets, employing lentivector gene delivery of the core clock gene Bmal1 (also known as Arntl)-luciferase reporter. Beta cells were stably labelled using a rat insulin2 promoter fluorescent construct. Single-islet/cell oscillation profiles were measured by combined bioluminescence-fluorescence time-lapse microscopy. RESULTS: Human islets synchronised in vitro exhibited self-sustained circadian oscillations of Bmal1-luciferase expression at both the population and single-islet levels, with period lengths of 23.6 and 23.9 h, respectively. Endogenous BMAL1 and CRY1 transcript expression was circadian in synchronised islets over 48 h, and antiphasic to REV-ERBα (also known as NR1D1), PER1, PER2, PER3 and DBP transcript circadian profiles. HNF1A and PDX1 exhibited weak circadian oscillations, in phase with the REV-ERBα transcript. Dispersed islet cells were strongly oscillating as well, at population and single-cell levels. Importantly, beta and non-beta cells revealed oscillatory profiles that were well synchronised with each other. CONCLUSIONS/ INTERPRETATION: We provide for the first time compelling evidence for high-amplitude cell-autonomous circadian oscillators displayed in human pancreatic islets and in dispersed human islet cells. Moreover, these clocks are synchronised between beta and non-beta cells in primary human islet cell cultures.
AIMS/HYPOTHESIS: Following on from the emerging importance of the pancreas circadian clock on islet function and the development of type 2 diabetes in rodent models, we aimed to examine circadian gene expression in human islets. The oscillator properties were assessed in intact islets as well as in beta cells. METHODS: We established a system for long-term bioluminescence recording in cultured human islets, employing lentivector gene delivery of the core clock gene Bmal1 (also known as Arntl)-luciferase reporter. Beta cells were stably labelled using a ratinsulin2 promoter fluorescent construct. Single-islet/cell oscillation profiles were measured by combined bioluminescence-fluorescence time-lapse microscopy. RESULTS:Human islets synchronised in vitro exhibited self-sustained circadian oscillations of Bmal1-luciferase expression at both the population and single-islet levels, with period lengths of 23.6 and 23.9 h, respectively. Endogenous BMAL1 and CRY1 transcript expression was circadian in synchronised islets over 48 h, and antiphasic to REV-ERBα (also known as NR1D1), PER1, PER2, PER3 and DBP transcript circadian profiles. HNF1A and PDX1 exhibited weak circadian oscillations, in phase with the REV-ERBα transcript. Dispersed islet cells were strongly oscillating as well, at population and single-cell levels. Importantly, beta and non-beta cells revealed oscillatory profiles that were well synchronised with each other. CONCLUSIONS/ INTERPRETATION: We provide for the first time compelling evidence for high-amplitude cell-autonomous circadian oscillators displayed in humanpancreatic islets and in dispersed human islet cells. Moreover, these clocks are synchronised between beta and non-beta cells in primary human islet cell cultures.
Authors: G Parnaud; D Bosco; T Berney; F Pattou; J Kerr-Conte; M Y Donath; C Bruun; T Mandrup-Poulsen; N Billestrup; P A Halban Journal: Diabetologia Date: 2007-11-10 Impact factor: 10.122
Authors: Andrew C Liu; David K Welsh; Caroline H Ko; Hien G Tran; Eric E Zhang; Aaron A Priest; Ethan D Buhr; Oded Singer; Kirsten Meeker; Inder M Verma; Francis J Doyle; Joseph S Takahashi; Steve A Kay Journal: Cell Date: 2007-05-04 Impact factor: 41.582
Authors: Ursula Loizides-Mangold; Laurent Perrin; Bart Vandereycken; James A Betts; Jean-Philippe Walhin; Iain Templeman; Stéphanie Chanon; Benjamin D Weger; Christine Durand; Maud Robert; Jonathan Paz Montoya; Marc Moniatte; Leonidas G Karagounis; Jonathan D Johnston; Frédéric Gachon; Etienne Lefai; Howard Riezman; Charna Dibner Journal: Proc Natl Acad Sci U S A Date: 2017-09-25 Impact factor: 11.205