Proinflammatory Cytokines Perturb Mouse and Human Pancreatic Islet Circadian Rhythmicity and Induce Uncoordinated β-cell Clock Gene Expression via Nitric Oxide, Lysine Deacetylases and Immunoproteasomal Activity

Abstract

Pancreatic β-cell-specific clock knock-out 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.

Human primary cells can tell body time: Dedicated to Steven A. Brown

“…The data revealed a rhythmic regulation of the mitochondrial fission protein DRP1, which serves as the molecular mediator of the circadian control of mitochondrial morphology and oxidative metabolism, helping to understand metabolic homeostasis in human health and disease (Schmitt et al, 2018). In the same direction, employing pancreatic islet cells from transgenic mice and from human donors, both expressing the circadian reporter Per2:luc, Andersen et al report that inflammatory stress perturb the intrinsic oscillators of islet cells with a potential link to diabetic phenotype (Andersen et al, 2021). Furthermore, in vitro circadian recordings of primary human cells provide important insights into disease prevention identified the perturbed clock components or downstream metabolic pathways as targets for potential therapeutic avenues for metabolic diseases (Petrenko et al, 2020;Petrenko et al, 2022;Petrenko et al, 2023;Sinturel et al, 2020).…”