title: A functional circadian clock is required for proper insulin secretion by human pancreatic islet cells.
abstract: OBJECTIVE
  To determine the impact of a functional human islet clock on insulin secretion and gene transcription.
  
  
  METHODS
  Efficient circadian clock disruption was achieved in human pancreatic islet cells by small interfering RNA-mediated knockdown of CLOCK. Human islet secretory function was assessed in the presence or absence of a functional circadian clock by stimulated insulin secretion assays, and by continuous around-the-clock monitoring of basal insulin secretion. Large-scale transcription analysis was accomplished by RNA sequencing, followed by quantitative RT-PCR analysis of selected targets.
  
  
  RESULTS
  Circadian clock disruption resulted in a significant decrease in both acute and chronic glucose-stimulated insulin secretion. Moreover, basal insulin secretion by human islet cells synchronized in vitro exhibited a circadian pattern, which was perturbed upon clock disruption. RNA sequencing analysis suggested alterations in 352 transcript levels upon circadian clock disruption. Among them, key regulators of the insulin secretion pathway (GNAQ, ATP1A1, ATP5G2, KCNJ11) and transcripts required for granule maturation and release (VAMP3, STX6, SLC30A8) were affected.
  
  
  CONCLUSIONS
  Using our newly developed experimental approach for efficient clock disruption in human pancreatic islet cells, we show for the first time that a functional β-cell clock is required for proper basal and stimulated insulin secretion. Moreover, clock disruption has a profound impact on the human islet transcriptome, in particular, on the genes involved in insulin secretion.
authors.affiliation: Endocrinology, Diabetes, Hypertension and Nutrition, Diabetes Centre, Faculty of Medicine, University of Geneva, Geneva, Switzerland.|Institute of Genetics and Genomics in Geneva (iGE3), Geneva, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Saini
authors.affiliation: Endocrinology, Diabetes, Hypertension and Nutrition, Diabetes Centre, Faculty of Medicine, University of Geneva, Geneva, Switzerland.|Institute of Genetics and Genomics in Geneva (iGE3), Geneva, Switzerland.
authors.forename: V
authors.initials: V
authors.lastname: Petrenko
authors.affiliation: Endocrinology, Diabetes, Hypertension and Nutrition, Diabetes Centre, Faculty of Medicine, University of Geneva, Geneva, Switzerland.|Diabetes Center, UCSF, San Francisco, CA, USA.
authors.forename: P
authors.initials: P
authors.lastname: Pulimeno
authors.affiliation: Endocrinology, Diabetes, Hypertension and Nutrition, Diabetes Centre, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Giovannoni
authors.affiliation: Department of Surgery, Cell Isolation and Transplantation Centre, University Hospital of Geneva, Geneva, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Berney
authors.affiliation: Diabetes Center, UCSF, San Francisco, CA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Hebrok
authors.affiliation: Institute of Genetics and Genomics in Geneva (iGE3), Geneva, Switzerland.|Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland.|Swiss Institute of Bioinformatics, Geneva, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Howald
authors.affiliation: Institute of Genetics and Genomics in Geneva (iGE3), Geneva, Switzerland.|Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland.|Swiss Institute of Bioinformatics, Geneva, Switzerland.
authors.forename: E T
authors.initials: ET
authors.lastname: Dermitzakis
authors.affiliation: Endocrinology, Diabetes, Hypertension and Nutrition, Diabetes Centre, Faculty of Medicine, University of Geneva, Geneva, Switzerland.|Institute of Genetics and Genomics in Geneva (iGE3), Geneva, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Dibner
mesh_terms: D056926:CLOCK Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D057906:Circadian Clocks / Q000187:drug effects; D005576:Colforsin / Q000494:pharmacology; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter / Q000187:drug effects; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D024661:Potassium Channels, Inwardly Rectifying / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D050765:Qa-SNARE Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051040:Vesicle-Associated Membrane Protein 3 / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000075703:Zinc Transporter 8; D000099161:Kcnj11 Channel
chemical_list: D056926:CLOCK Proteins; D027682:Cation Transport Proteins; D005576:Colforsin; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D007328:Insulin; D024661:Potassium Channels, Inwardly Rectifying; D050765:Qa-SNARE Proteins; D034741:RNA, Small Interfering; D000254:Sodium-Potassium-Exchanging ATPase; D051040:Vesicle-Associated Membrane Protein 3; D000075703:Zinc Transporter 8; D000099161:Kcnj11 Channel; C554061:GNAQ protein, human; C492522:SLC30A8 protein, human; C000612950:STX6 protein, human; C494946:VAMP3 protein, human; C538943:CLOCK protein, human; C499076:ATP1A1 protein, human
keywords: RNA sequencing; circadian bioluminescence; circadian clock; human pancreatic islet; insulin secretion