Project description:This study aims to elucidate nutrient dependent changes to the circadian transcriptome of whole flies. In particular, we aim to identify how dietary restriction influence circadian transcriptional output. Circadian analyses were performed to invesitigate diet-dependent changes in the number of circadian transcripts as well as their phases and circadian amplitude.
Project description:Circadian and metabolic processes are codependent. This experiment was designed to understand how a high fat diet affects circadian gene expression in the liver. Circadian gene expression in the liver is necessary for energy balance. Animals consuming normal chow or high fat diet (60% kcal from fat) for ten weeks were analyzed for circadian gene expression. Livers were harvested from animals every four hours throughout the circadian cycle.
Project description:Circadian and metabolic processes are codependent. This experiment was designed to understand how a high fat diet affects circadian gene expression in the liver. Circadian gene expression in the liver is necessary for energy balance.
Project description:Our objective was to identify candidate genes that contribute to the long 31-hour circadian period previously observed in DGRP_892. We performed transcriptional profiling of whole fly heads from two genotypes: DGRP_892, and Canton-S B, a line with a normal 24-hour circadian period. We collected fly heads every two hours over a 24-hour period. We quantified differential expression among genotype, time, and sex.
Project description:High fat diet (HFD), if prolonged, leads to obesity thereby accelerating the development of many ageing-related pathologies including chronic inflammation, cardiovascular disease, diabetes, and a higher predisposition to develop cancer. We asked whether HFD could reprogram the circadian output of young stem cells in a manner similar to what we observed during physiological ageing. HFD has been recently shown to induce a rewiring of the liver circadian transcriptome and metabolome, although in an obesity-independent manner. We therefore fed young (8 week old) C57Bl6 mice with HFD or its control diet for 7-weeks, a time when mice had not yet become obese, and performed circadian transcriptome analysis.
Project description:Even after decades of living in the same laboratory environment two Drosophila melanogaster strains originating from North America (Canton-S) and Central Russia (D18) demonstrate a few differentially expressed genes some of which may be important for local adaptation (e.g. genes responsible for insecticide resistance). Genes with different level of expression between Canton-S and D18 strains belong to important metabolic pathways, for instance energy metabolism, carbohydrate metabolic process, locomotion, body temperature rhythm regulation and tracheal network architecture. We used microarrays to make transcriptome profiling of two laboratory strains of different geographical origin after long-term laboratory maintenance
Project description:Maternal obesity has long-term effects on offspring metabolic health. Among the potential mechanisms, prior research has indicated potential disruptions in circadian rhythms and gut microbiota in the offspring. To challenge this hypothesis, we implemented a maternal high fat diet regimen before and during pregnancy, followed by a standard diet after birth. Our findings confirm that maternal obesity impacts offspring birth weight and glucose and lipid metabolisms. However, we found minimal impact on circadian rhythms and microbiota that are predominantly driven by the feeding/fasting cycle. Notably, maternal obesity altered rhythmic liver gene expression, affecting mitochondrial function and inflammatory response without disrupting the hepatic circadian clock. These changes could be explained by a masculinisation of liver gene expression similar to the changes observed in polycystic ovarian syndrome. Intriguingly, such alterations seem to provide the first-generation offspring with a degree of protection against obesity when exposed to a high fat diet.
Project description:Overnutrition disrupts circadian rhythms leading to dysregulated metabolism by mechanisms that are not well understood. Here we show that diet-induced obesity (DIO) causes massive remodeling of circadian enhancer activity and gene transcription in mouse liver. Remarkably, DIO triggers synchronous, high amplitude circadian rhythms of both fatty acid (FA) synthesis and oxidation. This gain of circadian rhythmicity in lipid metabolic pathways that oppose each other emphasizes the importance of balance and flux in normal hepatic lipid metabolism. DIO-promoted rhythmicity of Sterol Regulatory Element-Binding Protein (SREBP) activation, which was required not only for the induction of FA synthesis but also, surprisingly, for FA oxidation (FAO). DIO also brought about a high amplitude circadian rhythm of peroxisome proliferated receptor a (PPARa), which was required for FAO. Provision of a pharmacological ligand for PPARa abrogated the requirement of SREBP for FA oxidation (but not FA synthesis), suggesting that SREBP indirectly controls FA oxidation via production of an endogenous PPARa ligand. Moreover, the high amplitude circadian rhythm of PPARa imparts time-of-day-dependent responsiveness to lipid-lowering drugs. Thus, acquisition of rhythmicity for the non-core clock components PPARa and SREBP1 remodels metabolic gene transcription in response to a challenging nutritive environment and enables a chronopharmacological approach to metabolic disorders.
Project description:Influence of diet and neuronal clk (clock) activity on hemolymph proteomics. We have shown that as photoreceptors die (in the fly) they necrose, which results in their intercellular contents leaking into the hemolymph. We hypothesize that this process is regulated by diet and circadian clock control.
Analysis of differential protein expression in the hemolymph from flies reared on a high protein diet. Comparison of flies with and without a functional circadian clock within their photoreceptors.
Species/Strain: Drosophila, Elav-GeneSwitch-GAL4>UAS-Clk-DN1 (+/- RU486), female
Project description:The feeding/fasting cycles controlled by our circadian clock impose great daily metabolic and physiological changes, and yet investigations into the consequences of metabolic deficiencies, either dietary or genetic, have often ignored the time of day or the circadian time of the animals or subjects. In addition, these deficiencies may themselves disrupt our circadian clock, causing secondary metabolic, physiological and behavioural disorders. Dietary methionine/choline deficiency in rodents is a common model for human non-alcoholic steatohepatitis, but methionine and choline are nutrients essential for many other processes beyond fatty acid synthesis in the liver, including biological methylations and 1-carbon metabolism, regulation of translation notably via the mTOR pathway, phospholipid synthesis, polyamine pathway and glutathione synthesis. We have previously shown that circadian rhythms in many organisms are highly sensitive to deficiency or excesses of 1-carbon metabolites. Using a methionine/choline deficient diet in mice, we illustrate the nutrigenomic crosstalk between circadian rhythms and 1-carbon metabolism. We show not only that circadian locomotor activity behaviour is profoundly, rapidly and reversibly affected by methionine/choline deficiency, but also that the effects of methionine/choline deficiency on gene expression and 1-carbon metabolites are dependent on circadian time, illustrating the importance of considering circadian rhythms in metabolic studies. This study also highlights the impact of what we eat, or don't, on our behaviour and biological rhythms.