A fundamental challenge in the post-genome era is to understand and annotate the consequences of genetic variation, particularly within the context of human tissues. We describe a set of integrated experiments designed to investigate the effects of common genetic variability on DNA methylation, mRNA expression and microRNA (miRNA) expression in four distinct human brain regions. We show that brain tissues may be readily distinguished based on methylation status or expression profile. We find an abundance of genetic cis regulation mRNA expression and show for the first time abundant quantitative trait loci for DNA CpG methylation. We observe that the largest magnitude effects occur across distinct brain regions. We believe these data, which we have made publicly available, will be useful in understanding the biological effects of genetic variation.
Abundant quantitative trait loci exist for DNA methylation and gene expression in human brain.
Sex, Age, Specimen part
View SamplesParkinson disease (PD) is a major neurodegenerative condition with several rare Mendelian forms. Oxidative stress and mitochondrial function have been implicated in the pathogenesis of PD but the molecular mechanism(s) involved in the degeneration of specific neuronal groups remains unclear. DJ-1 mutations are one cause of recessive parkinsonism, but this gene is also involved in cancer by promoting Ras signaling and suppressing PTEN-induced apoptosis. The specific function of DJ-1 is unclear, although it is responsive to oxidative stress and may play a role in the maintenance of mitochondria. Here we show that DJ-1 associates with specific RNA targets in cells and in the brain including mitochondrial genes, genes involved in glutathione metabolism and members of the PTEN/PI3K cascade. Pathogenic recessive mutants are deficient in this activity. We show that DJ-1 is sufficient for RNA binding at nanomolar concentrations in vitro and that there is some RNA sequence specificity to the association. Oxidative stress causes DJ-1 to dissociate from RNA. Using in vitro and in vivo models of mild oxidative stress, we show that DJ-1 normally suppresses translation in normal circumstances but allows translation after oxidative stress. We tested the hypothesis that these specific RNA targets are responsible for sensitivity to stress by exposing knockout flies to glutathione synthesis inhibitors and saw the predicted increased sensitivity in vivo. These data implicate a single mechanism for the pleiotropic effects of DJ-1 in different model systems, namely that the protein binds and regulates specific groups of RNA targets in an oxidationdependent manner. Furthermore, these results suggest how a small protein might both be an upstream regulator of processes important in parkinsonism and be a modifier of cancer-related processes.
RNA binding activity of the recessive parkinsonism protein DJ-1 supports involvement in multiple cellular pathways.
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View SamplesResveratrol delays age-related deterioration and mimics transcriptional aspects of dietary restriction without extending lifespan
Resveratrol delays age-related deterioration and mimics transcriptional aspects of dietary restriction without extending life span.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Age-associated changes in basal NF-κB function in human CD4+ T lymphocytes via dysregulation of PI3 kinase.
Sex, Age, Specimen part, Treatment
View SamplesCalorie restriction (CR) is the most robust non-genetic intervention to universally delay the onset of age-related diseases and extend mean and maximum lifespan. However, species, strain, sex, diet, age of onset, and level of CR are emerging as important variables to consider for a successful CR response. Here, we investigated the role of strain, sex and level of CR on outcomes of health and survival in mice. Response to CR varied from lifespan extension to no effect on survival, while consistently delaying the onset and impact of diseases independently of strain, sex and level of dietary restriction. CR led to transcriptional and metabolomics changes in the liver indicating anaplerotic filling of the Krebs cycle together with fatty acid fueling of mitochondria. Additionally, CR prevented the age-associated decline in the proteostasis network. Further, CR increased mitochondrial number and preserved their ultrastructure and function with age. Abrogation of mitochondrial function by deletion of fumarate hydratase or malate dehydrogenase 2 negated the life-prolonging effects of CR in yeast and worms. In F1 hybrid strains of mice, the lifespan response to CR tracked with the dam, indicating that the mitochondrial haplotype is an important regulator of CR. Our data illustrate the complexity of the CR responses within a single animal species in the context of aging, with a clear separation of outcomes related to health and survival, highlighting the complexities of translation of CR into human interventions.
Effects of Sex, Strain, and Energy Intake on Hallmarks of Aging in Mice.
Sex, Specimen part
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 SamplesDeregulation of the translational machinery is emerging as a critical contributor to lymphomagenesis. Various miRNA alterations have been identified in lymphoma, but their role in disrupting the cap-dependent translation regulation complex remains poorly understood. Here, we demonstrate the translation initiation factor, eIF4GII, as a direct target and major mediator of miR-520c-3p function through 3UTR of eIF4GII mRNA. We established that elevated miR-520c-3p represses translation, initiates premature senescence and blocks cell proliferation in diffuse large B-cell lymphoma (DLBCL). Moreover, miR-520c-3p overexpression diminishes DLBCL cells colony formation and reduces tumor growth in a lymphoma xenograft mouse model. miR-520c-3p overexpressing cells display lowered eIF4GII levels. Consequently, downregulation of eIF4GII by siRNA induces cellular senescence, decreases cell proliferation and ability to form colonies. Our in vitro and in vivo findings we further validated in patient samples; DLBCL primary cells demonstrated low miR-520c-3p levels with reciprocally highly up-regulated eIF4GII protein expression. In contrast, normal donor B-cell lymphocytes had low levels of eIF4GII protein and elevated miR-520c-3p levels. Our results provide evidence that the tumor suppressor effect of miR-520c-3p is mediated through repression of cap-dependent translation while inducing senescence and that eIF4GII is a key effector of this anti-tumor activity. These findings may have implications for therapeutic interventions in patients with DLBCL.
Down-regulation of eIF4GII by miR-520c-3p represses diffuse large B cell lymphoma development.
Cell line
View SamplesImmune impairment and high circulating level of pro-inflammatory cytokines are landmarks of human aging. However, the molecular basis of immune dysregulation and the source of inflammatory markers remain unclear. Here we demonstrate that in the absence of overt cell stimulation, gene expression mediated by the transcription factor NF-B is higher in purified and rested human CD4+ T lymphocytes from older compared to younger individuals. This increase of NF-B -associated transcription includes transcripts for pro-inflammatory cytokines such as IL-1 and chemokines such as CCL2 and CXCL10. We demonstrate that NF-B up-regulation is cell-intrinsic and mediated in part by phosphatidylinositol 3-kinase (PI3K) activity induced in response to metabolic activity, which can be moderated by rapamycin treatment. Our observations provide direct evidence that dysregulated basal NF-B activity may contribute to the mild pro-inflammatory state of aging.
Age-associated changes in basal NF-κB function in human CD4+ T lymphocytes via dysregulation of PI3 kinase.
Sex, Age, Specimen part, Treatment
View SamplesThe 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
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Blast traumatic brain injury-induced cognitive deficits are attenuated by preinjury or postinjury treatment with the glucagon-like peptide-1 receptor agonist, exendin-4.
Sex, Specimen part, Treatment, Time
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