Project description:Ketone bodies, intermediates in energy metabolism and signaling, have attracted significant attention due to their role in health and disease. We performed around the clock study on ketone bodies and ketogenesis with mice on different diets. We found that caloric restriction, a dietary intervention that improves metabolism and longevity, induced high amplitude circadian rhythms in blood βOHB. The blood βOHB rhythms resulted from rhythmic ketogenesis in the liver controlled by the interaction between the circadian clock and PPAR transcriptional networks. This interaction results in transcriptional reprogramming of in beta-oxidation and ketogenesis enzymes. The reprogramming is impaired in circadian clock mutant mice. The circadian clock gated ketogenesis contributes to the diet impact on health and longevity.
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.
Project description:Methionine, a sulfur-containing essential amino acid, is a key component of dietary proteins important for protein synthesis, sulfur metabolism, antioxidant defense, and signaling. However, the role of methionine in cancer progression remains inconclusive. On one hand, dietary methionine restriction is known to repress cancer growth and improve cancer therapy in xenografted tumors. On the other hand, methionine is also critical for T cell activation and differentiation, making it a potential tumor suppression nutrient by enhancing T cell-mediated anti-tumor immunity. Here we investigated the interaction between dietary methionine, immune cells, and cancer cells by allografting CT26.WT mouse colon carcinoma cells into immunocompetent Balb/c mice or immunodeficient NSG mice, then analyzed how dietary methionine contents affect their growth. Our results show that dietary methionine restriction suppresses tumor growth in immunodeficient NSG mice but promotes tumor progression in immunocompetentt Balb/c mice.
Project description:Epigenetic modifications on DNA and histones regulate gene expression by modulating chromatin accessibility to transcription machinery. Chromatin-modifying enzymes are dependent on metabolic intermediates for chromatin remodeling, linking nutrient availability and cellular metabolism to the cellular epigenetic landscape. Here we identify methionine as a key nutrient affecting T cell epigenetic reprogramming in CD4+ T helper (Th) cells. Using metabolomic approaches, we showed that methionine is rapidly taken up by activated T cells and then serves as the major substrate for the biosynthesis of S-adenosyl-L-methionine (SAM), the universal methyl donor for cellular methyltransferases. Conversely, methionine restriction (MR) depletes intracellular SAM pools, reduces global histone H3K4 methylation (H3K4me3) in T cells, and reduces H3K4me3 levels at the promoter regions of key genes involved in CD4+ Th17 cell proliferation and cytokine production. Applied to the mouse model of multiple sclerosis (experimental autoimmune encephalomyelitis), dietary methionine restriction reduced the expansion of pathogenic Th17 cells in vivo, leading to reduced T cell-mediated neuroinflammation and disease onset. Overall our data identify methionine as a key nutritional factor that shapes T cell proliferation, differentiation, and function in part through regulation of histone methylation in T cells.
Project description:Epigenetic modifications on DNA and histones regulate gene expression by modulating chromatin accessibility to transcription machinery. Chromatin-modifying enzymes are dependent on metabolic intermediates for chromatin remodeling, linking nutrient availability and cellular metabolism to the cellular epigenetic landscape. Here we identify methionine as a key nutrient affecting T cell epigenetic reprogramming in CD4+ T helper (Th) cells. Using metabolomic approaches, we showed that methionine is rapidly taken up by activated T cells and then serves as the major substrate for the biosynthesis of S-adenosyl-L-methionine (SAM), the universal methyl donor for cellular methyltransferases. Conversely, methionine restriction (MR) depletes intracellular SAM pools, reduces global histone H3K4 methylation (H3K4me3) in T cells, and reduces H3K4me3 levels at the promoter regions of key genes involved in CD4+ Th17 cell proliferation and cytokine production. Applied to the mouse model of multiple sclerosis (experimental autoimmune encephalomyelitis), dietary methionine restriction reduced the expansion of pathogenic Th17 cells in vivo, leading to reduced T cell-mediated neuroinflammation and disease onset. Overall our data identify methionine as a key nutritional factor that shapes T cell proliferation, differentiation, and function in part through regulation of histone methylation in T cells.
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:Dietary methionine restriction (MR) has been shown to increase lifespan and decrease adiposity in rodents. This study was designed to examine the transcriptional effects of MR in metabolically relevant tissues. This experiment contains data from the liver. We analyzed MR-induced changes in gene expression using pooled RNA from liver of rats fed either a control purified amino acid diet (DL-methionine content of 0.86%) (CON) or a methionine-restricted diet (DL-methionine content of 0.172%)(MR). Rats were fed Purina rodent diet 5001 until 32 days of age and were then randomly assigned to be fed CON diet or MR diet for 20 months.
Project description:Dietary methionine restriction (MR) has been shown to increase lifespan and decrease adiposity in rodents. This study was designed to examine the transcriptional effects of MR in metabolically relevant tissues. This experiment contains data from the inguinal white adipose tissue (IWAT). We analyzed MR-induced changes in gene expression using pooled RNA from IWAT of rats fed either a control purified amino acid diet (DL-methionine content of 0.86%) (CON) or a methionine-restricted diet (DL-methionine content of 0.172%)(MR). Rats were fed Purina rodent diet 5001 until 32 days of age and were then randomly assigned to be fed CON diet or MR diet for 20 months.
Project description:Dietary methionine restriction (MR) has been shown to increase lifespan and decrease adiposity in rodents. This study was designed to examine the transcriptional effects of MR in metabolically relevant tissues. This experiment contains data from the liver.