The mammalian RNA-binding protein AUF1 (AU-binding factor 1, also known as heterogeneous nuclear ribonucleoprotein D, hnRNP D) binds to numerous mRNAs and influences their post-transcriptional fate. Given that many AUF1 target mRNAs encode muscle-specific factors, we investigated the function of AUF1 in skeletal muscle differentiation. In mouse C2C12 myocytes, where AUF1 levels rise at the onset of myogenesis and remain elevated throughout myocyte differentiation into myotubes, RIP (RNP immunoprecipitation) analysis indicated that AUF1 binds prominently to Mef2c (myocyte enhancer factor 2c) mRNA, which encodes the key myogenic transcription factor Mef2c. By performing mRNA half-life measurements and polysome distribution analysis, we found that AUF1 associated with the 3UTR of Mef2c mRNA and promoted Mef2c translation without affecting Mef2c mRNA stability. In addition, AUF1 promoted Mef2c gene transcription via a lesser-known role of AUF1 in transcriptional regulation. Importantly, lowering AUF1 delayed myogenesis, while ectopically restoring Mef2c expression levels partially rescued the impairment of myogenesis seen after reducing AUF1 levels. We propose that Mef2c is a key effector of the myogenesis program promoted by AUF1.
RNA-binding protein AUF1 promotes myogenesis by regulating MEF2C expression levels.
Sex, Specimen part, Cell line, Time
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Calorie restriction in humans inhibits the PI3K/AKT pathway and induces a younger transcription profile.
Specimen part
View SamplesWith 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.
Calorie restriction in humans inhibits the PI3K/AKT pathway and induces a younger transcription profile.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Conserved and species-specific molecular denominators in mammalian skeletal muscle aging.
Sex, Specimen part
View SamplesAging is a complex phenomenon involving functional decline in multiple physiological systems. We focused on skeletal muscle to identify pathways that modulate function and healthspan by global expression profiles and specific mechanisms fundamental to aging processes. Our experimental design integrated comparative analysis of mice, rats, rhesus monkeys and humans and targeted three key time points during their lifespans. Pathways related to oxidative stress, inflammation and nutrient signaling, which function collectively to affect the quality and status of mitochondria, emerged across all species with age. Notably, mitochondrial transcript levels were better preserved in aging human muscle, suggesting an evolution-driven fitness more robust than in other species. The identification of these conserved pathways uncovers common molecular mechanisms intrinsic to health and lifespan, while unveiling of species-specific pathways emphasizes the importance of human studies for devising optimal therapeutic modalities to slow the aging process.
Conserved and species-specific molecular denominators in mammalian skeletal muscle aging.
Sex, Specimen part
View SamplesAging is a complex phenomenon involving functional decline in multiple physiological systems. We focused on skeletal muscle to identify pathways that modulate function and healthspan by global expression profiles and specific mechanisms fundamental to aging processes. Our experimental design integrated comparative analysis of mice, rats, rhesus monkeys and humans and targeted three key time points during their lifespans. Pathways related to oxidative stress, inflammation and nutrient signaling, which function collectively to affect the quality and status of mitochondria, emerged across all species with age. Notably, mitochondrial transcript levels were better preserved in aging human muscle, suggesting an evolution-driven fitness more robust than in other species. The identification of these conserved pathways uncovers common molecular mechanisms intrinsic to health and lifespan, while unveiling of species-specific pathways emphasizes the importance of human studies for devising optimal therapeutic modalities to slow the aging process.
Conserved and species-specific molecular denominators in mammalian skeletal muscle aging.
Sex, Specimen part
View SamplesAging is a complex phenomenon involving functional decline in multiple physiological systems. We focused on skeletal muscle to identify pathways that modulate function and healthspan by global expression profiles and specific mechanisms fundamental to aging processes. Our experimental design integrated comparative analysis of mice, rats, rhesus monkeys and humans and targeted three key time points during their lifespans. Pathways related to oxidative stress, inflammation and nutrient signaling, which function collectively to affect the quality and status of mitochondria, emerged across all species with age. Notably, mitochondrial transcript levels were better preserved in aging human muscle, suggesting an evolution-driven fitness more robust than in other species. The identification of these conserved pathways uncovers common molecular mechanisms intrinsic to health and lifespan, while unveiling of species-specific pathways emphasizes the importance of human studies for devising optimal therapeutic modalities to slow the aging process.
Conserved and species-specific molecular denominators in mammalian skeletal muscle aging.
Sex, Specimen part
View SamplesMetformin, a commonly used drug prescribed to treat type-2 diabetes, has been found to extend health span and delay cancer incidence and progression. Here, we report that starting chronic treatment with low dose of metformin (0.1% w/w in diet) at one year of age extends health and lifespan in male mice, while a higher dose (1% w/w) was toxic. Treatment with low dose metformin mimicked some of the benefits of calorie restriction, such as improved physical performance, increased insulin sensitivity, and reduced LDL and cholesterol levels. At a molecular level, metformin increased AMP-activated protein kinase activity without attenuation of the mitochondrial electron transport chain activities. Metformin treatment resulted in lower chronic inflammation and increased antioxidant protection, suggesting that the ability of metformin to improve health of laboratory animals may stem from these factors. Our results support that metformin supplementation could be beneficial in extending health and lifespan in humans.
Metformin improves healthspan and lifespan in mice.
Sex, Specimen part
View SamplesThe Gata4 transcription factor is essential for normal heart development, but the molecular basis for its function remain poorly understood. We profiled at the whole genome level transcript changes in cardiomyocytes when Gata4 is depleted from zebrafish embryos. Our objective was to elucidate the cardiomyocyte-specific molecular program functioning downstream of Gata4 in order to better understand the role of Gata4 in cardiac morphogenesis. Overall design: Six samples in total are deposited. Three replicate control samples and three replicate Gata4 morphant samples were analyzed.
Small heat shock proteins Hspb7 and Hspb12 regulate early steps of cardiac morphogenesis.
No sample metadata fields
View SamplesThe E-protein transcription factors E2A and HEB play important roles at several stages of hematopoiesis. However, the exact mechanism for theire action and the main targets in the LY6D negative common lymphoid progentior (CLP) compartment remains unknown. By adressing this question, we will gain important infromation regarding the early events leading to B-cell specification.
The transcription factors E2A and HEB act in concert to induce the expression of FOXO1 in the common lymphoid progenitor.
Specimen part
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