Project description:The circadian system plays an essential role in regulating timing of body metabolism in humans. Indeed, circadian misalignments are strongly associated with high rates of metabolic disorders. Molecular makeup of the circadian oscillator can be deciphered in cells cultured in vitro, and these cellular rhythms are highly informative of the physiological circadian rhythm in vivo.
We aimed at assessing molecular clock properties in dermal fibroblasts established from the skin biopsies of seventeen Type 2 diabetic obese and non-obese patients and eleven healthy controls. Following in vitro synchronization, primary fibroblast cultures were subjected to continuous assessment of circadian bioluminescence profiles based on lentiviral luciferase reporters.
We observed a strong inverse correlation between HbA1c values and circadian period length within cells from the Type 2 diabetic group. RNA sequencing analysis conducted in this group samples revealed that ICAM1 encoding for the endothelial adhesion protein was differentially expressed between Type 2 diabetic compensated and non-compensated fibroblasts, and correlated with the period length. Furthermore, ICAM1 expression is driven by rhythmic CLOCK binding.
We provide for the first time a potential molecular link between severity of Type 2 diabetes and circadian clock machinery, which paves a way for further mechanistic understanding of circadian oscillator changes upon Type 2 diabetes in humans.
Project description:In the immune system various parameters and immune functions are controlled by the circadian system. To investigate molecular mechanisms that link the circadian clock and the immune system we analyzed the transcriptom of peritoneal macrophages from mice collected in a time course for two consecutive days. We found that more than 8% of expressed genes are under circadian control including many important regulators in pathogen recognition, signal transduction and cytokine secretion.
Project description:In the immune system various parameters and immune functions are controlled by the circadian system. To investigate molecular mechanisms that link the circadian clock and the immune system we analyzed the transcriptom of peritoneal macrophages from mice collected in a time course for two consecutive days. We found that more than 8% of expressed genes are under circadian control including many important regulators in pathogen recognition, signal transduction and cytokine secretion. Peritoneal macrophages from mice kept in constant conditions were isolated in 4 h intervalls over a period of 48 h. RNA of CD11b sorted cells was extracted, pooled from 3 mice per time point and used for microarray analysis.