| Autor: |
Andersen PAK; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark., Petrenko V; Division of Endocrinology, Diabetes, Nutrition and Patient Education, Department of Cell Physiology and Metabolism, Diabetes Center, Faculty of Medicine, University of Geneva, D05.2147c Rue Michel-Servet, 1 CH-1211 Geneva 4, Switzerland., Rose PH; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark., Koomen M; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark., Fischer N; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark., Ghiasi SM; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark., Dahlby T; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark., Dibner C; Division of Endocrinology, Diabetes, Nutrition and Patient Education, Department of Cell Physiology and Metabolism, Diabetes Center, Faculty of Medicine, University of Geneva, D05.2147c Rue Michel-Servet, 1 CH-1211 Geneva 4, Switzerland., Mandrup-Poulsen T; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, DK-2200 Copenhagen N, Denmark. |
| Abstrakt: |
Pancreatic β-cell-specific clock knockout mice develop β-cell oxidative-stress and failure, as well as glucose-intolerance. How inflammatory stress affects the cellular clock is under-investigated. Real-time recording of Per2:luciferase reporter activity in murine and human pancreatic islets demonstrated that the proinflammatory cytokine interleukin-1β (IL-1β) lengthened the circadian period. qPCR-profiling of core clock gene expression in insulin-producing cells suggested that the combination of the proinflammatory cytokines IL-1β and interferon-γ (IFN-γ) caused pronounced but uncoordinated increases in mRNA levels of multiple core clock genes, in particular of reverse-erythroblastosis virus α (Rev-erbα) , in a dose- and time-dependent manner. The REV-ERBα/β agonist SR9009, used to mimic cytokine-mediated Rev-erbα induction, reduced constitutive and cytokine-induced brain and muscle arnt-like 1 ( Bmal1 ) mRNA levels in INS-1 cells as expected. SR9009 induced reactive oxygen species (ROS), reduced insulin-1/2 ( Ins-1/2 ) mRNA and accumulated- and glucose-stimulated insulin secretion, reduced cell viability, and increased apoptosis levels, reminiscent of cytokine toxicity. In contrast, low (<5,0 μM) concentrations of SR9009 increased Ins-1 mRNA and accumulated insulin-secretion without affecting INS-1 cell viability, mirroring low-concentration IL-1β mediated β-cell stimulation. Inhibiting nitric oxide (NO) synthesis, the lysine deacetylase HDAC3 and the immunoproteasome reduced cytokine-mediated increases in clock gene expression. In conclusion, the cytokine-combination perturbed the intrinsic clocks operative in mouse and human pancreatic islets and induced uncoordinated clock gene expression in INS-1 cells, the latter effect associated with NO, HDAC3, and immunoproteasome activity. |
