BioProject

With the population of older and overweight individuals on the rise in the Western world, there is an ever greater need to slow the aging processes and reduce the burden of age-associated chronic disease that would significantly improve the quality of human life and reduce economic costs. More...

With the population of older and overweight individuals on the rise in the Western world, there is an ever greater need to slow the aging processes and reduce the burden of age-associated chronic disease that would significantly improve the quality of human life and reduce economic costs. Caloric restriction (CR), is the most robust and reproducible intervention known to delay aging and to improve healthspan and lifespan across species (1); however, whether this intervention can extend lifespan in humans is still unknown. Here we report that rats and humans exhibit similar responses to long-term CR at both the physiological and molecular levels. CR induced broad phenotypic similarities in both species such as reduced body weight, reduced fat mass and increased the ratio of muscle to fat. Likewise, CR evoked similar species-independent responses in the transcriptional profiles of skeletal muscle. This common signature consisted of three key pathways typically associated with improved health and survival: IGF-1/insulin signaling, mitochondrial biogenesis and inflammation. To our knowledge, these are the first results to demonstrate that long-term CR induces a similar transcriptional profile in two very divergent species, suggesting that such similarities may also translate to lifespan-extending effects in humans as is known to occur in rodents. These findings provide insight into the shared molecular mechanisms elicited by CR and highlight promising pathways for therapeutic targets to combat age-related diseases and promote longevity in humans. Overall design: Percutaneous biopsy specimens of vastus lateralis muscle were taken from 15 Human subjects from a group of middle-aged (58.7±7.4 yrs.), weight-stable members of the Calorie Restriction Society who have been practicing ~30% CR with adequate nutrition (at least 100% of RDI for each nutrient) for an average of 9.6 years and 10 age matched controls that were eating a typical Western diet. Total RNA was extracted from the skeletal muscle using Trizol Reagent (Invitrogen, Carlsbad, CA) following the manufacturer’s instructions, RNA quality and quantity was checked using an Agilent 2100 Bio-analyzer and the RNA 6000 nano-chips (Agilent Technologies, Palo Alto, CA). Total RNA samples were biotin labeled and hybridized to Sentrix Human HT-12, v3 Expression BeadChips (Illumina, San Diego, CA), following Illumina protocols. Arrays were washed, stained and scanned using an Illumina BeadArray 500GX reader. Microarray florescent signals were extracted using the Illumina GenomeStudio Gene Expression software(v1.6.0) and any spots at or below the background were filtered using an Illumina detection p-value of 0.02 and above. The natural log of all remaining scores were used to find the avg and std of each array and the z-score normalization was calculated . Correlation analysis, sample clustering analysis and principal component analysis include all of probes are performed to identify/exclude any possible outliners. The resulting dataset was next analyzed with DIANE 6.0, a spreadsheet based microarray analysis program. Gene set enrichment analysis use gene expression values or gene expression change values for all of the genes in the microarray. Parametric analysis of gene set enrichment (PAGE) was used [pubmed 20682848] for gene set analysis. Less...