Project description:Aging signatures developed from a longitudinal study design are dominated by reduced transcription of genes involved in protein synthesis. Aging is a multifactorial process where the impact of singular components still remains unclear. Furthermore, previous studies were focused on measuring specific traits such as DNA -methylation and used categorical group-wise designs, unable to capture intra-individual signature changes. Here we have developed a new method for a longitudinal, age-related analysis combining the merits of a pair-wise design with the statistical power of gene set enrichment analysis. We present an integrated analysis, including transcriptional changes and genome-wide epigenetic changes in DNA- methylation, H3K4- and H3K27- histone methylation in promoter regions. We tested our method on a rare collection of paired skin fibroblast samples from male middle age to old age transitions and obtained functional, age-related clusters. By using a set of only ten individuals, we could demonstrate a high overlap of functional terms to previously established tissue-independent age signatures including extracellular matrix, apoptosis and oxidative stress. Importantly, we identify protein translation-related processes as the main cluster of age-driven, specific down regulation. H3K4me3, H3K27me3 and DNA- methylation longitudinal aging profiles from primary skin fibroblasts from matched pairs of early (E) and late (L) stages in life.
Project description:Aging signatures developed from a longitudinal study design are dominated by reduced transcription of genes involved in protein synthesis Aging is a multifactorial process where the impact of singular components still remains unclear. Furthermore, previous studies were focused on measuring specific traits such as DNA -methylation and used categorical group-wise designs, unable to capture intra-individual signature changes. Here we have developed a new method for a longitudinal, age-related analysis combining the merits of a pair-wise design with the statistical power of gene set enrichment analysis. We present an integrated analysis, including transcriptional changes and genome-wide epigenetic changes in DNA- methylation, H3K4- and H3K27- histone methylation in promoter regions. We tested our method on a rare collection of paired skin fibroblast samples from male middle age to old age transitions and obtained functional, age-related clusters. By using a set of only ten individuals, we could demonstrate a high overlap of functional terms to previously established tissue-independent age signatures including extracellular matrix, apoptosis and oxidative stress. Importantly, we identify protein translation-related processes as the main cluster of age-driven, specific down regulation. Evaluation of transcriptional changes in matched sample pairs of primary skin fibroblasts from middle and old age.
Project description:Aging signatures developed from a longitudinal study design are dominated by reduced transcription of genes involved in protein synthesis Aging is a multifactorial process where the impact of singular components still remains unclear. Furthermore, previous studies were focused on measuring specific traits such as DNA -methylation and used categorical group-wise designs, unable to capture intra-individual signature changes. Here we have developed a new method for a longitudinal, age-related analysis combining the merits of a pair-wise design with the statistical power of gene set enrichment analysis. We present an integrated analysis, including transcriptional changes and genome-wide epigenetic changes in DNA- methylation, H3K4- and H3K27- histone methylation in promoter regions. We tested our method on a rare collection of paired skin fibroblast samples from male middle age to old age transitions and obtained functional, age-related clusters. By using a set of only ten individuals, we could demonstrate a high overlap of functional terms to previously established tissue-independent age signatures including extracellular matrix, apoptosis and oxidative stress. Importantly, we identify protein translation-related processes as the main cluster of age-driven, specific down regulation.
Project description:Aging signatures developed from a longitudinal study design are dominated by reduced transcription of genes involved in protein synthesis. Aging is a multifactorial process where the impact of singular components still remains unclear. Furthermore, previous studies were focused on measuring specific traits such as DNA -methylation and used categorical group-wise designs, unable to capture intra-individual signature changes. Here we have developed a new method for a longitudinal, age-related analysis combining the merits of a pair-wise design with the statistical power of gene set enrichment analysis. We present an integrated analysis, including transcriptional changes and genome-wide epigenetic changes in DNA- methylation, H3K4- and H3K27- histone methylation in promoter regions. We tested our method on a rare collection of paired skin fibroblast samples from male middle age to old age transitions and obtained functional, age-related clusters. By using a set of only ten individuals, we could demonstrate a high overlap of functional terms to previously established tissue-independent age signatures including extracellular matrix, apoptosis and oxidative stress. Importantly, we identify protein translation-related processes as the main cluster of age-driven, specific down regulation.
Project description:We characterized the longitudinal gene expression profiles of whole blood from a novel lupus model nephritis: SNF1 (SWR X NZB F1) mice treated with pristane. Genes from interferon, plasma cell, neutrophil, T-cell and protein synthesis signatures were differentially expressed in the pristane-SNF1 model compared to the untreated matched control animals.
Project description:We hypothesized that the estrogen-related receptor a (ERRa), which recruits PGC-1a to metabolic target genes in heart, exerts protective effects in the context of stressors known to cause heart failure. ERRa-/- mice subjected to left ventricular (LV) pressure overload developed signatures of heart failure including chamber dilatation and reduced LV fractional shortening. 31P-NMR studies revealed abnormal phosphocreatine depletion in ERRa-/- hearts subjected to hemodynamic stress, indicative of a defect in ATP reserve. Mitochondrial respiration studies demonstrated reduced maximal ATP synthesis rates in ERRa-/- hearts. Cardiac ERRa target genes involved in energy substrate oxidation, ATP synthesis, and phosphate transfer were downregulated in ERRa-/- mice at baseline or with pressure overload. These results demonstrate that ERRa, a potential therapeutic target, is indispensable for the adaptive bioenergetic response to hemodynamic stressors known to cause heart failure. Experiment Overall Design: Microarray analyses were performed with two samples each of ERRawt and ERRako to compare baseline changes in gene expression. Validation real-time PCR (n=7) was subsequently performed to characterize expression changes of gene targets identified in microarray and ChIP-chip studies in hearts of ERRa wt and KO mice at baseline and subjected to pressure overload stress.
Project description:Age-related defects in stem cells can limit proper tissue maintenance and hence contribute to a shortened life-span. Using highly purified hematopoietic stem cells from mice aged 2 to 21 months, we demonstrate a deficit in function yet an increase in stem cell number with advancing age. Expression analysis of more than 14,000 genes identified 1500 that were age-induced and 1600 that were age-repressed. Genes associated with the stress response, inflammation, and protein aggregation dominated the upregulated expression profile, while the downregulated profile was marked by genes involved in the preservation of genomic integrity and chromatin remodeling. Many chromosomal regions showed coordinate loss of transcriptional regulation, and an overall increase in transcriptional activity with aged, and inappropriate expression genes normally regulated by epigenetic mechanisms was observed. Hematopoietic stem cells from early-aging mice expressing a mutant p53 allele reveal that aging of stem cells can be uncoupled from aging at an organismal level. These studies show that HSC are not protected from aging. Instead, loss of epigenetic regulation at the chromatin level may drive both functional attenuation of cells, as well as other manifestations of aging, including the increased propensity for neoplastic transformation. Experiment Overall Design: Time course contains four time points in duplicate. Whole bone marrow and p53 mutant arrays were used in a pairwise comparison and age estimate calculation, respectively.
Project description:Protein synthesis is strictly regulated during replicative aging in yeast, but global translational regulation during replicative aging is poorly characterized. To conduct ribosomal profiling during replicative aging, we collected a large number of dividing aged cells using a miniature chemostat aging device. Translational efficiency, defined as the number of ribosome footprints normalized to transcript abundance, was compared between young and aged cells for each gene. We identified more than 700 genes with changes greater than twofold during replicative aging. Increased translational efficiency was observed in genes involved in DNA repair and chromosome organization. Decreased translational efficiency was observed in genes encoding ribosome components, transposon Ty1 and Ty2 genes, transcription factor HAC1 genes associated with the unfolded protein response, genes involved in cell wall synthesis and assembly, and ammonium permease genes. Our results provide a global view of translational regulation during replicative aging, in which the pathways involved in various cell functions are translationally regulated and cause diverse phenotypic changes.
Project description:A prospective, randomized and controlled study is proposed to establish whether an enteral nutrition support regimen based on pressurized whey protein and glucose improves the postoperative utilization of amino acid substrates compared to a drink based on glucose alone. The kinetics of protein metabolism (protein breakdown, protein synthesis and amino acid oxidation) will be investigated using stable isotope methodology before and after surgery in patients undergoing colon resection. Stable isotope infusions will be conducted one week before surgery and on the second postoperative day for two hours in the fasted state and for four hours while sipping the enteral nutrition support regimen. Patients will consume one of two enteral nutrition support regimens consisting of a drink containing either pressurized whey protein and glucose or glucose alone. It is hypothesized that an enteral nutrition support regimen based on pressurized whey protein and glucose promotes positive protein balance through increased protein synthesis or reduced protein breakdown compared to glucose alone.