Project description:Dietary restriction (DR), a reduction in food intake without malnutrition, increases most aspects of health during ageing and extends lifespan in diverse species including rodents and rhesus monkeys. However the mechanisms by which DR interacts with the ageing process to improve health at old age are poorly understood. DNA methylation could play an important role in mediating the effects of DR, because it is sensitive to the effects of nutrition and can affect gene expression memory over time. Here we have profiled genome-wide changes in DNA methylation, gene expression and lipidomics in response to DR and ageing in mouse liver. DR strongly retarded age-related changes in DNA methylation. With ageing, DNA methylation became confined to genic elements and was associated with reduced gene expression, particularly of genes involved in lipid metabolism.
Project description:Consumption of beans protects from the development of obesity. We established that dietary bean exerts dose- and sex-dependent effects on the liver transcriptome in the context of lipid metabolism, which prevents the onset of metabolic-associated fatty liver disease.
Project description:DNA methylation (DNAm) is one of the most reliable biomarkers of aging across many mammalian tissues. While the age-dependent global loss of DNAm has been well characterized, age-dependent DNAm gain is less specified. Multiple studies have demonstrated that polycomb repressive complex 2 (PRC2) targets are enriched among the CpG sites which gain methylation with age. However, systematic whole-genome examination of all PRC2 targets in the context of aging methylome as well as determination of the pan-tissue or tissue-specific nature of these associations is lacking. Here, by analyzing DNAm data from different assays and from multiple young and old human and mouse tissues, we found that low-methylated regions (LMRs) which are highly bound by PRC2 in embryonic stem cells (PRC2 LMRs) gain methylation with age in all examined somatic mitotic cells. We also estimated that this epigenetic change represents around 90% of the age-dependent DNAm gain genome-wide. Therefore, we propose the “PRC2-AgeIndex,” defined as the average DNAm in PRC2 LMRs, as a universal biomarker of cellular aging in somatic cells. In addition, we demonstrate the application of this biomarker in the evaluation of different anti-aging interventions, including dietary restriction and partial epigenetic reprogramming.
Project description:DNA methylation (DNAm) is one of the most reliable biomarkers of aging across many mammalian tissues. While the age-dependent global loss of DNAm has been well characterized, age-dependent DNAm gain is less specified. Multiple studies have demonstrated that polycomb repressive complex 2 (PRC2) targets are enriched among the CpG sites which gain methylation with age. However, systematic whole-genome examination of all PRC2 targets in the context of aging methylome as well as determination of the pan-tissue or tissue-specific nature of these associations is lacking. Here, by analyzing DNAm data from different assays and from multiple young and old human and mouse tissues, we found that low-methylated regions (LMRs) which are highly bound by PRC2 in embryonic stem cells (PRC2 LMRs) gain methylation with age in all examined somatic mitotic cells. We also estimated that this epigenetic change represents around 90% of the age-dependent DNAm gain genome-wide. Therefore, we propose the “PRC2-AgeIndex,” defined as the average DNAm in PRC2 LMRs, as a universal biomarker of cellular aging in somatic cells. In addition, we demonstrate the application of this biomarker in the evaluation of different anti-aging interventions, including dietary restriction and partial epigenetic reprogramming.
Project description:Aims/hypothesis: Dietary restriction (DR) reduces adiposity and improves metabolism in patients with one or more symptoms of the metabolic syndrome. Nonetheless, it remains elusive whether the benefits of DR in humans are mediated by calorie or nutrient restriction. This study was conducted to identify whether isocaloric dietary protein restriction is sufficient to confer the beneficial effects of dietary restriction in patients with metabolic syndrome. Methods: We performed a prospective, randomized controlled dietary intervention under constant nutritional and medical supervision. A total of 21 individuals diagnosed with the metabolic syndrome was randomly assigned for caloric restriction (CR; n = 11, mean age 49 ± 8.5 years, female 63%; diet of 5,941 ± 686 KJ per day) or isocaloric dietary protein restriction (PR; n = 10, mean age 51.6 ± 8.9 years, female 50%; diet of 8,409 ± 2,360 KJ per day) and followed for 27 days. Results: Like CR, PR promoted weight loss (-6.6%, P= 0.0041) due to reduction in adiposity (-9.9%, P= 0.0007), associated with reductions in blood glucose (-52.7%, P= 0.0002), lipid levels (cholesterol, -35.4%, P= 0.0010; triglycerides, -39.5% P= 0.0022) and blood pressure (systolic, -37.7 P< 0.0001; diastolic, -73.2% P< 0.0001). PR resulted in enrichment of metabolic pathways related to the immune system such as B cell proliferation, lymphocyte proliferation and leukocyte proliferation in subcutaneous adipose tissue. Hence, a reduction in calorie intake or changes in the gut microbiome are not necessary to confer the metabolic benefits of DR. Instead, a reduction in protein intake with a mild increase in carbohydrate intake to maintain the isocaloric balance of the diet is sufficient to improve metabolic control. Conclusions/interpretation: Protein restriction is sufficient to confer almost the same clinical outcomes as calorie restriction without the need for a reduction in calorie intake. The isocaloric characteristic of the PR intervention makes this approach a more attractive and less drastic dietary strategy in clinical settings and has greater potential to be used as adjuvant therapy for people with the metabolic syndrome.
Project description:Caloric restriction (CR) improves survival in nonhuman primates and delays the onset of age-related morbidities including sarcopenia, the age-related loss of muscle mass and function. A shift in metabolism anticipates the onset of muscle aging phenotypes in nonhuman primates suggesting a potential role for metabolism in CR’s protective effects. Here we show that CR induced profound changes in muscle composition and the cellular metabolic environment. Bioinformatic analysis linked these adaptations to proteostasis, RNA processing, and lipid synthetic pathways. At the tissue level, CR maintained contractile content and attenuated age-related metabolic shifts among individual fiber types with higher mitochondrial activity, altered redox metabolism, and smaller lipid droplet size. Biometric and metabolic rate data confirm preserved metabolic efficiency in CR animals that correlated with attenuation of age-related muscle mass and physical activity. These data suggest that CR-induced reprogramming of metabolism plays a role in delayed aging of skeletal muscle in rhesus monkeys.
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:The ground state of pluripotency is defined as a basal proliferative state free of epigenetic restriction, represented by mouse embryonic stem cells (ESCs) cultured with two kinase inhibitors (so-called “2i”). Through comparison with serum-grown ESCs, we identify epigenetic features characterizing 2i ESCs by proteome profiling of chromatin including post-translational histone modifications. The most prominent difference is H3K27me3 and its enzymatic writer complex PRC2 that are highly abundant on eu- and heterochromatin in 2i ESCs, with H3K27me3 redistributing outside canonical PRC2 targets in a CpG-dependent fashion. Using PRC2-deficient 2i ESCs, we identify epigenetic crosstalk with H3K27me3, including significant increases in H4 acetylation and DNA methylation. This suggests that the unique H3K27me3 configuration protects 2i ESCs from preparation to lineage priming. Interestingly, removal of DNA methylation in PRC2-deficient 2i ESCs lacking H3K27me3 using 5-azacytidine hardly affected ESC viability and transcriptome, showing that ESCs are independent of both major repressive epigenetic marks.